Review of Polydora species from Brazil, with identification key and description of two new species (Annelida: Spionidae)

Abstract

This study aimed to review previous records of Polydora species from Brazil, as well as provide new records, mainly from the Southeast and South regions of the country. In total, 11 species were distinguished and a key to their identification is given. Polydora cornuta , P. nuchalis , and a new species from the state of Rio de Janeiro, P. nonatoi sp. nov. were found to occur in silty sand tubes in soft sediments; six species were found to be opportunistic commensals boring in shells of various molluscs; P. colonia was found to only bore in sponges; and a new species, P. paulolanai sp. nov., was found to bore in both sponges and oyster shells in Paraná state. Adults of P. nonatoi sp. nov. have black stripes on the palps, black spots on the peristomium and 3−4 anterior chaetigers, short occipital antenna, falcate spines of chaetiger 5 with a large lateral tooth connected to main stem by thin sheath, and only capillary chaetae in the posterior notopodia. Adults of P. paulolanai sp. nov. have black bands on the palps, short occipital antenna, falcate spines of chaetiger 5 with transverse subdistal collar on concave side, and numerous needle-like spines loosely held in tufts in addition to capillary chaetae in the posterior notopodia. Polydora caeca Webster, 1879 is resurrected and treated here as a senior subjective synonym of P. neocaeca Williams & Radashevsky, 1999. Shell-boring worms from Brazil earlier identified as P. neocaeca or P. cf. haswelli Blake & Kudenov, 1978 are referred to P. caeca . The urgent need of molecular data for the correct identification of Polydora species from Brazilian waters is highlighted.

Keywords:  Polychaete; Morphology; Taxonomy; Shell-boring; Biodiversity

INTRODUCTION

Polydora Bosc, 1802 is one of the largest genera of the family Spionidae Grube, 1850 (Annelida). Initially, it comprised all spionids with heavy spines in the notopodia of segment 5, but later it was divided into several closely related genera, such as Dipolydora Verrill, 1881 , Pseudopolydora Czerniavsky, 1881, Polydorella Augener, 1914, and others (Blake and Kudenov, 1978 ; Blake, 1996 ). At present, these genera are combined in the tribe Polydorini Benham, 1896 (Radashevsky, 2012 ). Currently Polydora comprises at least 53 species, including several that are poorly known and require verification and redescription (Blake et al., 2020 ). Adult Polydora occur in diverse habitats from the intertidal to deep water. They construct silty tubes in soft sediments and bore into various substrata, including mollusc shells, barnacle tests, corals, coralline algae, and sponges. Specific identification of polydorins is often problematic due to 1) brief original descriptions of some species that were never redescribed based on material from the type locality, 2) high ontogenetic and individual variability of their morphology, 3) large number of species in which adults appear very similar to each other, 4) lack of molecular data for many species, and 5) numerous introductions of worms throughout the world.

In a comprehensive revision of Spionidae from South America, Antarctica, and adjacent seas and islands, Blake ( 1983 ) reported 14 species of Polydora , six of which were subsequently transferred to the genus Dipolydora . Blake ( 1983: 270) noted that “The spionid fauna of most of Brazil remains largely unknown” and did not report any Polydora species from Brazilian waters. The first records of Polydora from Brazil were provided by Lana ( 1986 ), who reported two species from Paranaguá Bay (Paraná): P. socialis (Schmarda, 1861) and P. websteri Hartman in Loosanoff & Engle, 1943 . The former species was subsequently transferred to the genus Dipolydora . These two species alone were repeatedly reported from Brazil by various authors until Radashevsky ( 2004 ) reported P. colonia Moore, 1907 and P. cornuta Bosc, 1802 , and Pardo et al. ( 2005 ) reported P. neocaeca Williams & Radashevsky, 1999 and P. nuchalis Woodwick, 1953 from the Southeast-South region of Brazil. Radashevsky et al. ( 2006 ) reviewed Polydora species boring into oyster shells in South America and, for the first time in Brazil, reported P. ecuadoriana Blake, 1983 , P. cf. haswelli Blake & Kudenov, 1978 , P. rickettsi Woodwick, 1961 , and also described a new species, P. carinhosa Radashevsky, Lana & Nalesso, 2006 . Radashevsky and Migotto ( 2017 ) reported P. hoplura Claparède, 1868 from São Paulo state for the first time in Brazil and South America. After these reports, the taxonomic status of some species was modified. The only identification key for Brazilian Polydora included four species boring into oyster shells (Radashevsky et al., 2006 ).

The purpose of this study was to review previous and provide new records of Polydora species from Brazil, compose an identification key for these species, and highlight problems with their taxonomy and identification.

METHODS

Collections were conducted by the author in shallow waters along the coast of Brazil, mainly from the state of Espírito Santo south to the state of Paraná in 1998−2015. Sediments, molluscs, barnacles, coralline algae, and sponges were collected using SCUBA equipment and grabs. Sediments collected for this study were washed in the field on a 500-µm mesh sieve, and Polydora worms retained in the residue were removed, relaxed in isotonic magnesium chloride, and then examined alive under light microscopes in the laboratory. Boring Polydora worms were removed from the infested shells or other hard substrata with a hammer and pliers and examined in the laboratory. Additional Polydora specimens were provided by Paulo Lana, Álvaro Migotto, Rosebel Nalesso, Karla Costa, João Nogueira, Elianne Omena, Yasmine Neptune, and also examined in various collections and museums in Brazil. Drawings were made using a camera lucida. Worm fragments were preserved in 95% ethanol for future molecular analysis. After morphological examination in life, some worms were fixed in 10% formalin solution, rinsed in fresh water, and transferred to 70% ethanol. Formalin-fixed specimens stored in ethanol were stained with an ethanol solution of methyl green (MG), following the procedure described by Radashevsky et al. ( 2023b ), and then photographed using light microscopes equipped with digital cameras. Images of multiple focal layers were stacked using the Zerene Stacker software version 1.04. Images of parts of worms were stitched into panoramas using PTGui software version 12.22. After complete examination, specimens were deposited in the polychaete collections of Museu Nacional, Rio de Janeiro (MNRJP), Rio de Janeiro, Brazil; Museu de Zoologia da Universidade de São Paulo (MZUSP), São Paulo, Brazil; Museu de Diversidade Biológica da Universidade Estadual de Campinas (MDBio-IB/UNICAMP), Campinas, São Paulo, Brazil; Museum of the A.V. Zhirmunsky National Scientific Center of Marine Biology (MIMB), Vladivostok, Russia; Senckenberg Museum (SMF), Frankfurt am Main, Germany; and the National Museum of Natural History (USNM), Smithsonian Institution, Washington, D.C., USA. Brief information on the deposition of Polydora specimens from Brazil in museum collections precedes remarks on the species; the number of specimens in a sample is given in parentheses after the museum abbreviation and registration number. Complete information on the type specimens of the new species described in the present study precedes species description. Supplementary Tables S1 , S2, S3, S4, S5, S6, S7, S8, S9, S10 and S11 show complete information on the whole material examined during this study and records by other authors. Table ESM12 shows a list of the museums and other collections (and their acronyms) holding the samples that are reported in this study.

When no coordinates were provided for sampling sites from other studies, they were estimated using Google Earth Pro according to the original descriptions of the locations. Sampling locations noted in Tables S1−11 are plotted on maps using the QGIS software version 3.28.0 and the geodata provided by the OpenStreetMap Project ( https://osmdata.openstreetmap.de ). Final maps and plates were prepared using the CorelDRAW®2022 software.

RESULTS

This work has been registered with ZooBank under https://zoobank.org/56D61369-D118-4601-9091-B092B1AF2B4E

This work has Supplementary material under https://zenodo.org/records/8337187

Polydora Bosc, 1802

List of Polydora species from Brazil

(including their modes of life and type localities)

1. Polydora caeca Webster, 1879a . Shell borer. Virginia, Atlantic USA.

2. Polydora carinhosa Radashevsky, Lana & Nalesso, 2006 . Shell borer. Paranaguá Bay, Paraná, Brazil.

3. Polydoracolonia Moore, 1907 . Sponge borer. Martha’s Vineyard Island, Massachusetts, Atlantic USA.

4. Polydora cornuta Bosc, 1802 . Tube dweller. Charleston, South Carolina, Atlantic USA.

5. Polydora ecuadoriana Blake, 1983 . Shell borer. Bahía de Santa Elena, Ecuador.

6. Polydora hoplura Claparède, 1868 . Shell borer. Gulf of Naples, Tyrrhenian Sea, Mediterranean, Italy.

7. Polydora nuchalis Woodwick, 1953 . Tube dweller. Los Angeles, California, Pacific USA.

8. Polydora cf. rickettsi Woodwick, 1961 . Shell borer. Lower California, Pacific Mexico.

9. Polydora nonatoi sp. nov. Tube dweller. Rio de Janeiro, Brazil.

10. Polydorapaulolanai sp. nov. Sponge and shell borer. Paranaguá Bay, Paraná, Brazil.

11. Polydora cf. websteri Hartman in Loosanoff & Engle, 1943 . Shell borer. Milford, Connecticut, Atlantic USA.

Key to Polydora adults from Brazil ¹

1. Inhabiting silty tubes in soft sediments. Occipital antenna present. Posterior notopodia with only capillary chaetae.........................................................................….2

– Boring into calcareous substrata or sponges. Occipital antenna present or absent. Posterior notopodia with or without modified spines in addition to capillary chaetae.........................................................................….4

2(1) Black paired stripes present on palps and anterior lateral sides of prostomium. Black paired spots present on dorsal side of 1−4 anterior chaetigers. Falcate spines of chaetiger 5 usually with a large lateral tooth connected to main stem by thin sheath, occasionally with a small lateral tooth and a small vertical flange above it................… P. nonatoi sp. nov.

– Black pigment absent on palps, head, and 1−3 anterior chaetigers........................................................................3

3(2) Chaetiger 5 without dorsal superior and ventral capillary chaetae. Falcate spines of chaetiger 5 with a small lateral tooth and a small vertical flange above it. Companion chaetae of chaetiger 5 with feathery, disheveled tip, closely adhering to convex side of falcate spines........................................................................................… P. cornuta

– Chaetiger 5 with dorsal superior and ventral capillary chaetae. Falcate spines of chaetiger 5 simple, without accessory structures. Companion chaetae of chaetiger 5 compact, pennoned, not adhering to convex side of falcate spines.............................................................… P. nuchalis

4(1) Falcate spines of chaetiger 5 with a transverse subdistal collar on concave side. Boring into sponges or calcareous substrata...........................................................................5

– Falcate spines of chaetiger 5 with a lateral tooth and/or flange. Boring mainly into calcareous substrata...............6

5(4) Boring into sponges only. Caruncle to end of chaetiger 2. Occipital antenna absent. Posterior notopodia with heavy recurved spines in addition to capillary chaetae ........................................................................................… P. colonia

– Boring into sponges and mollusc shells. Caruncle to end of chaetiger 3. Low occipital antenna present. Posterior notopodia with numerous needle-like spines loosely held in tufts and greatly protruding out of body wall in addition to capillary chaetae................................. P. paulolanai sp. nov.

6(4) Occipital antenna present. Posterior notopodia with heavy recurved spines in addition to capillary chaetae. Falcate spines of chaetiger 5 with a lateral flange .......… P. hoplura

– Occipital antenna absent. Posterior notopodia with only capillary chaetae or with tight packets of needle-like spines in addition to capillary chaetae. Falcate spines of chaetiger 5 with a lateral tooth and/or flange................….7

7(6) Posterior notopodia with tight packets of needle-like spines in addition to capillary chaetae. Falcate spines of chaetiger 5 with a lateral tooth.....................................… P. carinhosa

– Posterior notopodia with only capillary chaetae.............…8

8(7) Pygidium large, scoop-shaped..................... P. ecuadoriana

– Pygidium small, disc-like to cup-shaped...........................9

9(8) Prostomium anteriorly entire, occasionally weakly incised. Falcate spines of chaetiger 5 with a lateral tooth and a small vertical flange above it......................…. P. cf. rickettsi

– Prostomium anteriorly weakly incised to bilobed. Falcate spines of chaetiger 5 with a lateral flange of variable size ² ............................................................................….10

10(9) Pigmentation usually well developed, including black bands on palps, narrow black stripes on anterior lateral sides of prostomium (in front of the eyes), paired spots on dorsal side of peristomium and 2−4 anterior chaetigers and unpaired median spots on ventral side of chaetigers 2−4; however, some spots may be absent in some individuals. Caruncle to middle of chaetiger 4 ........................ P. caeca

– Pigmentation absent on body segments. Narrow continuous (occasionally partially discontinuous) black line present along the margins of frontal groove of palps. Caruncle usually to end of chaetiger 2, occasionally to middle of chaetiger 3.................................... P. cf. websteri

Polydora caeca Webster, 1879a

Polydora caeca Webster, 1879a a: 252–253, pl. IX: Figures 119–122. Not Leucodorum coecum Örsted, 1843 . Fide Hartman in Loosanoff and Engle, 1943 .

Polydora neocaeca Williams & Radashevsky, 1999: 117–127, Figures 1 - 5 (adult and larval morphology). Williams, 2000: 123–129, Figures 1 - 3 (sperm ultrastructure). Pardo et al., 2005: 209, text Figures A–D. Malan et al., 2020: 9–12, Figures 2 - 4 (References). Davinack and Hill, 2022: 123–128. New synonymy.

Polydora cf. haswelli: Lana et al., 2006: 50. Radashevsky et al., 2006: 17–22, Figures 8, 9 . Pagliosa et al., 2012 (Part.): 45 (References).

Polydora haswelli: Read and Handley, 2004: 30–31, text Figures. Glasby et al., 2009: 320, 324, text Figure. Read, 2010: 83–100, Figures 1A–G, 2A, C, E, 3A, B, 4A–C . Sato-Okoshi et al., 2012: 85, Figures 2F, 3D, 4C, 5A, . Sato-Okoshi and Abe, 2013: 1282, Figure 4 A–F. Not Blake and Kudenov, 1978 . Fide Malan et al., 2020 .

Polydora websteri: Lana, 1986: Table 3. Bolívar and Lana, 1987: 115–116, Figures 8–20; 1988: 247–267. Blankensteyn and Moura, 2002: 718, Table 2. Sabry and Magalhães, 2005: 194–203. Pontinha, 2009: 28–29. Not Hartman in Loosanoff and Engle, 1943 . Fide Radashevsky et al., 2006 .

Material . MZUSP 174, 176, 178, 179 (141); MDBio-IB/UNICAMP 7003 (2); MIMB 44745 (1); USNM 1022188 (2).

Complete information on the lost holotype of P. caeca (Virginia, Atlantic USA), type specimens of P. neocaeca (Rhode Island, USA), and specimens of P. caeca from South America (Brazil) is given in Table S1 (mapped in Figure S1 ).

Habitat . Adults occur in the intertidal and in shallow water, making U-shaped burrows in shells of the mangrove oyster Crassostrea brasiliana (Lamarck, 1819), mangrove cupped oyster Crassostrea rhizophorae (Guilding, 1828), Pacific oyster Magallana gigas (Thunberg, 1793), saddle oyster Anomia ephippium Linnaeus, 1758, alive gastropod Crepidula plana Say, 1822, and empty shells of the gastropods Lithopoma tectum ([Lightfoot], 1786), Gemophos auritulus (Link, 1807), Pisania pusio (Linnaeus, 1758), Pugilina morio (Linnaeus, 1758), Siratus senegalensis (Gmelin, 1791), Stramonita haemastoma (Linnaeus, 1767), Strombus pugilis (Linnaeus, 1758), and Agathistoma viridulum (Gmelin, 1791) inhabited by hermit crabs Clibanarius vittatus (Bosc, 1802 ), Paguristes tortugae Schmitt, 1933 and Pagurus brevidactylus (Stimpson, 1859), and also in live scleractinian corals. Up to 10 worms occurred per cm ² of shell surface.

Diagnostic features . Palps with up to 13 paired black bands on sides of frontal groove; narrow black stripes on anterior lateral sides of prostomium (in front of eyes); paired black spots on dorsal side of peristomium and 2−4 anterior chaetigers; unpaired median black spots on ventral side of chaetigers 2−4 (some spots absent in some individuals). Prostomium incised anteriorly. Caruncle extending to middle of chaetiger 4 (shorter in small individuals). Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a lateral flange of variable size. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap. Spermatids joined in tetrads.

Remarks onPolydora caeca/websteri/neocaeca . Leucodorum coecum Örsted, 1843 was described from Öresund, Denmark. Claparède ( 1863: 37; 1869: 53−54) showed that “the genus Leucodore Johnst. and Polydora Bosc must be united” and “The name Polydora Bosc would then have to be retained as the older one.” However, it took decades until Polydora Bosc, 1802 name was adopted by other zoologists and Leucodore Johnston, 1838 (often misspelled as Leucodora or Leucodorum ) stopped being used. In this period of uncertainty, Webster ( 1879a ) described Polydora caeca Webster, 1879a boring in the shell of the jingle shell Anomia glabra Verrill, 1872 (= Anomia simplex d’Orbigny, 1853) in Virginia, USA. Webster ( 1879a ) gave no precise locality but, as explained in his introductory comments (Webster, 1879a a: 2), “The locality was in Northampton Co., Virginia (Eastern shore of Va.), between the main-land and the line of outside islands,” in the muddy shallows, probably at approximately 37.288°N, 75.9206°W ( Figure S1 ).

According to Claparède ( 1863 , 1869 ), Leucodore coecum Örsted, 1843 was transferred to Polydora and the two names for a while were in use simultaneously: Polydora coeca (Örsted) (also spelled regularly as P. caeca ) for tube-dwelling worms in the North East Atlantic (e.g., Saint-Joseph, 1894 ) and Polydora caeca Webster for shell-boring worms in the North West Atlantic (e.g., Andrews, 1891 ). Verrill ( 1881 ) established a new genus Dipolydora Verrill, 1881 , to which Polydora coeca (Örsted) should belong. However, Dipolydora was not in general use until Blake ( 1996 ) resurrected it and transferred to it a group of Polydora species (including Dipolydora coeca [Örsted]). In the intervening years, the two spellings “ coeca ” and “ caeca ” were regarded as the same for the purposes of homonymy (ICZN, 1905: Article 36), and thus Loosanoff and Engle ( 1943: 70) stated that Polydora websteri Hartman was a “new name” for P. caeca Webster. Although Hartman herself never explicitly stated that P. websteri was a replacement name for P. caeca Webster, she noted (in personal correspondence with Loosanoff and Engle – see Loosanoff and Engle [ 1943: 70]) that “the original description of the worm, as P. caeca , was published by Webster, 1879a ” and included P. caeca Webster in the synonymy of P. websteri (e.g., Hartman in Loosanoff & Engle, 1943 , Hartman, 1945 , 1959 ). Thus, P. websteri Hartman was long considered a replacement name for P. caeca Webster.

Comparing syntypes of P. websteri with the description of P. caeca by Webster ( 1879a ), specimens collected by S. H. Hopkins ( 1960 ) from oyster shells in Northampton County, Virginia (USNM 45201) (the type locality of P. caeca ), and newly collected Polydora worms boring into gastropod shells in Rhode Island, USA, Radashevsky and Williams ( 1998 ) realized that Webster ( 1879a ) and Hartman ( 1943 ) dealt with two different species. Consequently, Radashevsky and Williams ( 1998 ) applied to the International Commission on Zoological Nomenclature (ICZN) for P. websteri to be conserved and not treated as a replacement name for P. caeca Webster. This application was granted (ICZN, 2001: Opinion 1974) and a lectotype from Milford, Connecticut, USA (the type locality of P. websteri ), was designated for P. websteri by Radashevsky ( 1999 ).

Since Webster’s single specimen of P. caeca was missing from all possible museums, and taking for granted Hartman’s ( 1943: 70) note that “the description (of P. caeca by Webster [ 1879a ]) is faulty and misleading in all essential respects, it has little value for systematics,” Williams and Radashevsky ( 1999 ) described their specimens from Rhode Island ( Figure S1 ) as a new species, Polydora neocaeca Williams & Radashevsky, 1999 . These specimens were boring in shells of living gastropods, gastropod shells occupied by hermit crabs, and bivalve shell fragments. However, Webster’s ( 1879a: 52–53) description of P. caeca , in fact, was detailed and correct in all essential respects, except for his misinterpretation of the parapodia of the first segment: “First segment with dorsal ramus only; ramus small and with shorter setae than those of the following segments.” However, this misinterpretation is quite common even at present, as the notopodia of the first segment in Polydora worms are usually small and achaetous, and neuropodia are better developed, shifted dorsally almost to the level of notopodia of the following segments and bear short capillary chaetae (see Malan et al., 2020: Figure 4 b). What is essential and has important value for systematics, is Webster’s ( 1879a: 52–53) note that in his specimen “A rounded carination [caruncle, VIR] extends from the head to the anterior margin of the 4th segment” and “This species can readily be distinguished from any previously described from our coast by the purple [black, VIR] markings on the tentacles.” The same was confirmed by Radashevsky and Williams ( 1998: 213): “Specimens from Rhode Island and Virginia represent the only shell-boring Polydora species with banded palps and caruncle extending beyond segment 2 on the Atlantic coast of North America.” In the Comment on the proposed conservation of P. websteri , Radashevsky and Williams ( 2000: 111) noted “We believe this [ P. neocaeca ] to be the same taxon as P. caeca Webster, 1879a , the name for which is a junior secondary homonym of P. coeca (Örsted, 1843 ), a tube-dwelling spionid.” In retrospect, however, this conclusion was incorrect since Blake ( 1996 ) had already resurrected Dipolydora Verrill and transferred P. coeca (Örsted, 1843 ) to it; thus, the two names were in fact not homonyms at that time.

Describing the new species, Williams and Radashevsky ( 1999: 116) noted that it was “to replace the permanently invalid name P. caeca .” However later, Radashevsky and Williams ( 2000: 111) clarified that, in fact, the name P. neocaeca Williams & Radashevsky “was established as that of a new nominal species, and not as a replacement (nomen novum) for P. caeca Webster,” and therefore “has its own holotype, description and type locality” in Bluff Hill Cove, Rhode Island. In the end of the Comment on P. websteri , Radashevsky and Williams ( 2000: 111) noted once again: “We believe that P. neocaeca represents the same taxon as Webster described.”

The removal of P. websteri and P. neocaeca from the replacement status by the International Commission on Zoological Nomenclature (ICZN) (2001), as well as the clarification by Radashevsky and Williams ( 2000 ), lead to the situation described in the Article 59.3 of the Code (ICZN, 1999): “A junior secondary homonym replaced before 1961 is permanently invalid unless the substitute name is not in use and the relevant taxa are no longer considered congeneric….” Both of these conditions now apply, and thus P. caeca Webster can be considered as an available name again, which no longer has a replacement name and does not require one as a junior secondary homonymy no longer exists, i.e., it can be considered as a senior subjective synonym of P. neocaeca Williams & Radashevsky. Therefore, to resolve the uncertainty of the names, and in accordance with Article 59.3 of the Code, Polydora neocaeca Williams & Radashevsky, 1999 is treated here (and as explained further below) as a junior subjective synonym of Polydora caeca Webster, 1879a .

Remarks onPolydora neocaeca/haswelli . Establishing P. neocaeca , Williams and Radashevsky ( 1999 ) overlooked Polydora haswelli from sandy bottom of Sydney Harbour, Australia, described by Blake and Kudenov ( 1978 ). The original description of the latter species ambiguously referred to the “additional pigment on palps” (Blake and Kudenov, 1978: 259) and “sand” as the habitat from which the type specimens came. Later James A. Blake (in litt. to VIR, 3 November 2003) clarified that “pigment spots occurred along the palps.” This clarification made P. neocaeca similar to the Australian species and raised an identity issue. Radashevsky et al. ( 2006 ) noted that the two species have similar adult morphology but differ in the shape of additional structures on the falcate spines of chaetiger 5: large accessory tooth and smaller vertical flange above the tooth in P. haswelli (Blake and Kudenov, 1978: Figure 44C–E), and a wide flange in P. neocaeca (Williams and Radashevsky, 1999: Figure 1 D). They noted, however, that the spine lateral structures may vary (see also Read, 2010: 90) and are not always useful for species delineation. Spermatid aggregations were suggested to distinguish at least the Brazilian and North American populations, as this character was (and still is) unknown for Australian worms. The number of spermatids joined together by cytoplasmic bridges is species specific, with four or eight in examined Polydora species, and has been used for distinguishing between sibling species (see Radashevsky and Pankova, 2006 ; Radashevsky, 2022 ). Spermatids of the Brazilian worms were joined in tetrads, whereas Williams ( 2000 ) noted that spermatids of P. neocaeca from Rhode Island were joined in octads. In this context, Radashevsky et al. ( 2006 ) suggested that the two populations were different and tentatively referred the Brazilian worms to P. cf. haswelli . Strangely enough, such a simple and important character as the spermatid aggregations has never been observed by any other researcher out of many considerations of Polydora worms. Thus, I checked formalin-fixed specimens of P. neocaeca from Rhode Island (MIMB 44771) and found that the spermatids are, in fact, joined in tetrads. I observed the same aggregations of spermatids in worms with the same morphological characteristics from Brazil (as noted above), China, South Korea, Vietnam, and Kuwait. Sequences of gene fragments of worms from all these locations were also similar to sequences of P. neocaeca from Rhode Island (provided by Malan et al., 2020 ), thus they all are considered as conspecific (Radashevsky et al., unpublished).

Regarding the type specimens of P. haswelli , Blake and Kudenov ( 1978: 259) noted: “Sydney Harbour, 8-10 m, near N. Chinamens Beach, sand, 8 May 1971, coll. P. Hutchings (HOLOTYPE, AM W 7283; 12 PARATYPES, AM W130.42; 5 PARATYPES, NMV G2883).” Recently, James A. Blake (in litt. to VIR, 16 February 2024) clarified that “the specimens designated as types were all from”sand” provided by Pat Hutchings; none of these had anything to do with shell borers.” However, along with these types, Blake and Kudenov ( 1978 ) reported three non-type specimens of P. haswelli from oyster mud blisters in Camden Haven, Australia (NMV G3058 – now MV F43058). This gave the impression that P. haswelli is capable of boring in mollusc shells, and soon the species was reported as boring in oysters, mussels, and scallops in Australia and New Zealand (Skeel, 1979 ; Pregenzer, 1983 ; Handley, 2003 ; Read and Handley, 2004 ; Glasby et al., 2009 ; Read, 2010 ). Even Blake ( 1996: 172) after almost 20 years after the original description indicated that P. haswelli was “a shell borer,” although Hutchings and Murray ( 1984 ) reported this species from sand in seagrass beds in Botany Bay, New South Wales, Australia. Outside of Australia and New Zealand, shell-boring P. cf. haswelli was first reported from Brazil (from Espírito Santo south to Santa Catarina) (Radashevsky et al., 2006 ). Polydora haswelli was then suggested to be distributed “widely and commonly in mollusk shells at least in Australia, New Zealand, Korea, and possibly Japan and Canada” (Sato-Okoshi et al., 2012: 89), and then reported from Japan (Sato-Okoshi and Abe, 2013 ), China (Ye et al., 2015 , 2019 ), and South Korea (Lee et al., 2020 ). Gradually, it was suspected that the tube-building holotype and paratypes of P. haswelli collected from the sandy bottom of Sydney Harbour may not be conspecific with shell-boring worms in Australia and other countries (Walker, 2013 ). A similar case occurred with Polydora triglanda Radashevsky & Hsieh, 2000 from Taiwan, which was initially considered capable of boring mollusc shells and building tubes in soft sediments, but later it was shown that the two ecological forms are not conspecific (Radashevsky and Pankova, 2013 ).

In an attempt to solve the taxonomy of the morphologically similar P. haswelli and P. neocaeca , Malan et al. ( 2020: 50) reexamined the type specimens of the former and, “based on the shape of the modified spines of chaetiger 5 and methyl green staining patterns,” hypothesized that “sand tube-dwelling […] and shell-boring species identified as P. haswelli are different species.” They also found that fragments of the nuclear 18S rRNA and mitochondrial COI of shell-boring worms from South Africa, Japan, and China were similar to those of P. neocaeca from its type locality in Rhode Island, and recommended that “shell-boring species previously identified as P. haswelli be referred to P. neocaeca .” The spread of this species around the globe was explained by possible transportation “with infested molluscs for aquaculture or by shipping” (Malan et al., 2020: 50). Limited sampling did not permit the authors to draw any conclusion regarding the native range for P. neocaeca , which remains unclear to date.

As noted above, the shell-boring worms from Brazil with black bands on the palps, caruncle extending at east to the end of chaetiger 3, falcate spines of chaetiger 5 with lateral flange, and spermatids joined in tetrads are morphologically identical to P. caeca from Virginia (USNM 45201) and P. neocaeca from Rhode Island. Therefore, I refer them all to P. caeca described by Webster ( 1879a ) from Virginia. Blake and Kudenov ( 1978 ) did not note which specimen(s) they used for the drawings provided in the original description of P. haswelli . The arguments provided by Malan et al. ( 2020 ) regarding non-conspecificity of the tube-dwelling and shell-boring forms of P. neocaeca from Australia appear to be realistic, although neither of these forms has yet been genetically assessed. Referring all shell-boring worms with morphological characteristics described above, including the ones from Australia to P. neocaeca , as suggested by Malan et al. ( 2020 ), would continue taxonomic uncertainty. Treating the name P. neocaeca Williams & Radashevsky as a junior subjective synonym of P. caeca Webster resolves this uncertainty. This scenario will be resolved when a neotype of P. caeca Webster is established, and when the tube-dwelling and shell-boring forms of P. neocaeca from Sidney Harbour are compared by molecular analysis.

Outside of its type locality, P. neocaeca was first reported from São Paulo, Brazil, boring in shells of gastropods and bivalves, including oysters (Pardo et al., 2005 ). In Brazil, shell-boring and tube-dwelling Polydora have been widely reported as P. websteri and P. cf. haswelli in numerous dissertations, reports and articles studying the ecological conditions of shallow benthic communities. However, these worms are usually not deposited in museum collections. At this time, most of these records cannot be assigned to one species or another.

Polydora carinhosa Radashevsky, Lana & Nalesso, 2006

Polydora carinhosa Radashevsky, Lana and Nalesso, 2006: 25−30, Figures 10−13 (adult and larval morphology).

Material . MZUSP 181 (holotype), 182 (paratype).

Complete information on the type specimens of P. carinhosa from Paraná, Brazil is given in Table S2 (mapped in Figure S2 ).

Habitat . Adults make U-shaped burrows in shells of the cultured mangrove cupped oyster Crassostrea rhizophorae (Guilding, 1828) and the Pacific oyster Magallana gigas (Thunberg, 1793).

Diagnostic features . Palps with narrow continuous black lines on sides of frontal groove; black paired spots on dorsal sides of peristomium and 2−4 anterior characters. Prostomium rounded, entire anteriorly. Caruncle extending to middle of chaetiger 3. Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a small lateral tooth. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap.

Remarks . Polydora carinhosa was originally described based on two specimens from Paraná and Santa Catarina ( Figure S2 ) (Radashevsky et al., 2006 ) and has not been reported since. The worms were females boring into shells of the mangrove oyster Crassostrea rhizophorae (Guilding, 1828) and the giant oyster Magallana gigas (Thunberg, 1793). Both of them brooded larvae in capsules attached by thin stalks to the inner wall of their burrows. The species is remarkable because the development of larvae is completely lecithotrophic, occurring entirely inside the capsules. Both examined broods contained fully developed larvae; therefore, the type of lecithotrophy (adelphophagia or endolecithotrophy) could not be established. However, since the larvae had long serrated provisional bristles in the notopodia, it was suggested that the larvae feed on nurse eggs, and this species probably exhibits adelphophagia (exolecithotrophy). In June 2008, I found similar broods with fully developed larvae of the same morphology in Polydora burrows in oyster shells in Taiwan. Adults have not been found, so the presence of P. carinhosa in Taiwan and the Western Pacific in general requires further study.

Polydora colonia Moore, 1907

Polydora colonia Moore, 1907: 199−201, pl. XV, Figures 18−23. Hartman, 1945: 32−33. Blake, 1971: 15−17, Figure 10; 1983: 253−255. Dauer, 1973: 193. Radashevsky, 2004: 1/1. Lana et al., 2006: 49. Neves and da Rocha, 2008: 625. David and Williams, 2012a: 317−323, Figures 1−4; 2012b (References): 1512−1524, Figures 1−6. Langeneck et al., 2020: 257−258. Gouillieux et al., 2022: 34, Figure 3 .

Polydora ancistrata Jones, 1962: 185−187, Figures 55−65. Fide Blake, 1971: 15.

Polydora hoplura inhaca Day, 1957: 99, Figure 6 k−l; 1967: 468, Figure 18.2n. Fide Blake, 1971: 15.

Material . MIMB 44717−44721 (150+); MZUSP 162−164 (270+); MNRJP 335, 336 (40); MDBio-IB/UNICAMP 16972 (3).

Complete information on the holotype of P. colonia (Massachusetts, Atlantic USA) and specimens of this species from South America (Argentina, Brazil) is given in Table S3 (mapped in Figure S3 ).

Habitat . Adults make burrows in sponges Tedania ignis (Duchassaing & Michelotti, 1864), Mycale ( Carmia ) microsigmatosa Arndt, 1927, and Desmacella cf. annexa Schmidt, 1870.

Diagnostic features . Prostomium rounded, entire anteriorly. Caruncle extending to end of chaetiger 2. Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a transverse subdistal collar on concave side. Posterior notopodia with heavy recurved spines in addition to capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap. Spermatids joined in octads.

Chaetiger 5 falcate spines with a collar on the subdistal concave side are also present in Polydora spongicola Berkeley & Berkeley, 1950 and Polydora paulolanai sp. nov. described below. Remarkably similar recurved spines in the posterior notopodia are also present in several other spionids, including some species of Boccardiella Blake & Kudenov, 1978 , Poecilochaetus Claparède in Ehlers, 1875, and P. hoplura among Polydora .

Remarks . Polydora colonia was originally described from Vineyard Haven, Massachusetts, Atlantic USA ( Figure S3 ) (Moore, 1907 ). David and Williams ( 2012a ) reviewed extensive records of this species along the Atlantic coast of North and South America. In Europe, P. colonia has been reported from Italy (Occhipinti-Ambrogi et al., 2010 ; Langeneck et al., 2020 ), and Atlantic France (Gouillieux et al., 2022 ). Sexual reproduction and larval development of this species have never been described, but asexual reproduction by architomy from off Long Island, New York, USA, has been described in detail by David and Williams ( 2012b ).

In the West Atlantic, P. colonia has been found only in sponges, where the worms make burrows, the walls of which are lined with silt. In the western Mediterranean, this species has been reported as associated (boring?) with coralline algae (Aguirre et al., 1986 ; San Martín and Aguirre, 1991 ; Tena et al., 2000 ). David and Williams ( 2012a ) reexamined the material and confirmed the identification of Aguirre et al. ( 1986 ). However, Langeneck et al. ( 2020 ) suggested that algae-boring worms may represent a different species. Very few spionids are obligate sponge commensals, and among Polydora species only P. spongicola Berkeley & Berkeley, 1950 from the North Pacific shares this lifestyle (Radashevsky, 1993 ).

In South America, P. colonia was first reported from the province of Buenos Aires, Argentina (Blake, 1983 ). In Brazil, this species was recorded from the states of Paraná and Rio de Janeiro (Radashevsky, 2004 ; Lana et al., 2006 ; Neves and da Rocha, 2008 ). In this study, I report this species for the state of São Paulo for the first time. The conspecificity of disjunct populations of P. colonia in California, Argentina and Brazil requires further study.

Polydora cornuta Bosc, 1802

Polydora cornuta Bosc, 1802: 151–153, pl. 12, Figures 7 - 8 . Blainville, 1828: 443. Blake and Maciolek, 1987: 12−14, Figure 1 . Blake, 1996: 171, Figure 4 .28H. Radashevsky, 2005: 3−19, Figures 1 - 4 (adult and larval morphology, references). Bertasi, 2016: 79−85, Figures 2 - 5 . Abe and Sato-Okoshi, 2021: 49−50, Figure 8 C, D . Boltachova et al., 2021: 14−15, Figure 2 . Dağlı et al., 2023: 3−5, Figure 2 .

Polydora ligni Webster, 1879a b: 119; 1886: 148–149, pl. 8, Figures 45–47. Fide Blake and Maciolek, 1987 .

Material . IBUFRJ 465 (4); MDBio-IB/UNICAMP 208−210, 517, 1000−1002, 1005, 1007, 1009, 1011, 1012, 1014−1018, 1020, 16974−16979 (879); MIMB 44726−44728 (50); MZUSP 165 (1); SMF 13975, 13978 (3); USNM 1020474, 1020475 (62+).

Complete information on the neotype of P. cornuta (South Carolina, Atlantic USA) and specimens of this species from South America (Argentina, Brazil, and Uruguay) is given in Table S4 (mapped in Figure S4 ).

Habitat . Adults build tubes in soft sediments and on the surface of hard substrata, including mollusc shells.

Diagnostic features . Individuals up to about 50-chaetiger stage with remains of small larval melanophores on anterior lateral sides from chaetigers 3–13 (usually from chaetiger 6 or 7) to chaetigers 15–22; larger individuals usually unpigmented. Prostomium bifurcated anteriorly. Caruncle extending to end of chaetiger 3. Cirriform occipital antenna present. Chaetiger 5 without dorsal superior and ventral capillaries; heavy falcate spines with a small lateral tooth and a small subdistal vertical flange; companion chaetae with feathery, disheveled tips tightly adhered to the convex side of falcate spines. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap. Spermatids joined in octads.

Remarks . Polydora cornuta , originally described from South Carolina ( Figure S4 ) (Bosc, 1802 ) and widely known by its junior synonym Polydora ligni Webster, 1879a , has been reported from temperate and subtropical waters throughout the world. Blake and Maciolek ( 1987 ) designated the neotype, redescribed the species, and showed that P. cornuta is a senior synonym of P. ligni .

Adult worms usually live in silt or mud tubes in soft sediments, but also often build their tubes on the surface of other organisms, including cultured molluscs. An excessive number of worms on shell surface can lead to the accumulation of huge quantities of silt, causing smothering and death of oysters (Mortensen and Galtsoff, 1944 ; Galtsoff, 1964 ). In 1940, P. cornuta thus destroyed acres of oyster beds in the Delaware Bay, USA (Nelson and Stauber, 1940 ). Galtsoff ( 1964 ) reported on several occasions that the reproductive rate of P. cornuta in the Delaware Bay was so rapid that nearly every living oyster in the area was killed by a few inches of mud. Although the native range of P. cornuta has never been postulated, all recent world records of this species treat it as alien, non-native. Transportation in ballast waters and ship fouling, as well as on the surface of commercial molluscs, has been proposed as the main vectors of distribution of this species.

There are quite a few genetic studies on P. cornuta , and they are mainly focused on local populations (Rice et al., 2007 ; Takata et al., 2011 ; David and Krick, 2019 ; Abe and Sato-Okoshi, 2021 ). Rice et al. ( 2007 ) suggested that P. cornuta populations in North America represent a cryptic species complex of at least three distinct lineages but did not study or permit further study of these. The conspecificity of disjunct populations of P. cornuta around the world requires further study.

In South America, P. cornuta was first reported as P. ligni from Argentina (Orensanz and Estivariz, 1971 ; Orensanz, 1982 ; Blake, 1983 ; Gutiérrez et al., 2000 ). In Brazil, the species was also first reported as P. ligni (Lopes, 1993 ; Amaral et al., 2010 ); however, after a revision by Blake and Maciolek ( 1987 ), it was listed as P. cornuta (Radashevsky, 2004 ; Pardo et al., 2005 ). Reproduction and larval development of P. cornuta in Paranaguá Bay (Paraná) was described in detail by Radashevsky ( 2005 ). Scarabino ( 2006 ) reported this species from Uruguay.

Polydora ecuadoriana Blake, 1983

Polydora ecuadoriana Blake, 1983: 257–258, Figure 26. Radashevsky et al., 2006: 7−17, Figures 2−7 (adult and larval morphology).

Material . MZUSP 166−172, 313, 315 (156); SMF 13930, 13967, 14010 (148+); USNM 1022185−1022187 (42); MIMB 44743, 44743 (37).

Complete information on the holotype of P. ecuadoriana (Bahía de Santa Elena, Ecuador) and specimens of this species from South America (Brazil) is given in Table S5 (mapped in Figure S5 ).

Habitat . Adults make U-shaped burrows in shells of the mangrove oyster Crassostrea brasiliana (Lamarck, 1819), mangrove cupped oyster Crassostrea rhizophorae (Guilding, 1828), Pacific oyster Magallana gigas (Thunberg, 1793), the barnacle Megabalanus sp., alive gastropod Stramonita haemastoma (Linnaeus, 1767), and empty shells of the gastropods Pugilina morio (Linnaeus, 1758), Stramonita haemastoma , Strombus pugilis (Linnaeus, 1758), and Agathistoma viridulum (Gmelin, 1791) inhabited by hermit crabs Clibanarius vittatus (Bosc, 1802 ), Paguristes tortugae Schmitt, 1933, and Pagurus brevidactylus (Stimpson, 1859).

Diagnostic features . Palps with up to seven black bands or narrow continuous or discontinuous black lines on sides of frontal groove; occasionally palps unpigmented. Prostomium incised anteriorly. Caruncle extending to end of chaetiger 3. Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a lateral tooth and a small subdistal longitudinal flange. Posterior notopodia with only capillary chaetae. Pygidium large, scoop-shaped, with wide middorsal gap. Spermatids joined in tetrads.

Remarks . Polydora ecuadoriana was originally described based on specimens boring into coralline algae and mollusc shells from Bahía de Santa Elena, Ecuador ( Figure S5 ) (Blake, 1983 ). Radashevsky et al. ( 2006 ) reported this species from Quintana Roo and Veracruz, Mexico, and described the morphology, reproduction, and larval development of worms from southern Brazil. The species has not been reported since. The conspecificity of disjunct populations of P. ecuadoriana in Ecuador and Brazil requires further study.

In Brazil, P. ecuadoriana occurs intertidally and in shallow water boring into shells of the mangrove oyster Crassostrea brasiliana (Lamarck, 1819), mangrove cupped oyster Crassostrea rhizophorae (Guilding, 1828), giant oyster Magallana gigas (Thunberg, 1793), barnacle Megabalanus sp., and empty shells of the gastropods Pugilina morio (Linnaeus, 1758), Stramonita haemastoma (Linnaeus, 1767), Strombus pugilis Linnaeus, 1758, and Tegula viridula (Gmelin, 1791) inhabited by hermit crabs Clibanarius vittatus (Bosc, 1802 ), Paguristes tortugae Schmitt, 1933, and Pagurus brevidactylus (Stimpson, 1859). The worms make U-shaped burrows inside shells and often cause formation of dark blisters on the inner shell surface both in native and cultured oysters. Severely infested oysters have up to 50% of the inner shell surface covered by blisters. These molluscs may have more than one hundred worms in one valve.

Polydora hoplura Claparède, 1868

Polydora hoplura Claparède, 1868: 318–319, pl. XXII, Figure 2 ; 1869: 58–59, pl. XXII, Figure 2 ; 1870: 58–59, pl. XXII, Figure 2 . Radashevsky et al., 2017: 545−551, Figures 2−4 (references); 2023b: 7−9, Figure 4 (references). Radashevsky and Migotto, 2017: 860–865, Figures 2–5 (adult and larval morphology).

Polydora ( Polydora ) hoplura: Rioja, 1931 ( Part .): 70, pl. 19, Figures 8–13. Hartmann-Schröder, 1971: 305; 1996: 318.

Polydora hoplura hoplura: Day, 1967: 468, Figure 18.2k–m.

Leucodora sanguinea Giard, 1881: 71–73. Fide Dollfus, 1921: 17; 1932: 275.

Polydora uncinata Sato-Okoshi, 1998: 278–280, Figure 1 ; 1999: 835. Radashevsky and Olivares, 2005: 491–494, Figures 2–4. Sato-Okoshi et al., 2008: 493–495, Figures 2–3; 2012: 87, Figures 4A–B, D. Sato-Okoshi and Abe, 2012: 43–44, Figure 3 . Fide Radashevsky et al., 2017: 545; Sato-Okoshi et al., 2017: 1678.

Material . MIMB 28149 (3); MZUSP 312 (4).

Complete information on the neotype of P. hoplura (Gulf of Naples, Italy) and specimens of this species from North and South America (California, USA; Brazil and Chile) is given in Table S6 (mapped in Figure S6 ).

Habitat . Adults make U-shaped burrows in the shells of bivalves and gastropods, including clams, scallops, oysters, and cultured abalone. Occasionally, worms bore into barnacle tests, sponges, coralline algae, and corals.

Diagnostic features . Palps with up to 25 black bands; black narrow longitudinal stripes on lateral sides of anterior part of prostomium (in front of eyes) and a pair of small black patches on dorsal side of peristomium; individuals up to 50–60-chaetiger stage with remains of small larval melanophores on dorso-lateral sides of 15–16 anterior chaetigers (pigmentation partially or completely absent in some individuals). Prostomium weakly incised anteriorly. Caruncle extending to end of chaetiger 3. Short occipital antenna present. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with large lateral flange. Posterior notopodia with two kinds of spines (heavy sickle-shaped and slender awl-like) in addition to capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap.

Remarks . Polydora hoplura , originally described from the Gulf of Naples, Tyrrhenian Sea, Italy, by Claparède ( 1868 ) ( Figure S6 ), has been recorded in temperate and subtropical waters throughout the world (Radashevsky et al., 2023b ). The same worms from Japan were described as a new species Polydora uncinata Sato-Okoshi, 1998 and recorded under this name in Australia, Chile, South Korea, and South Africa. Radashevsky et al. ( 2017 ) designated the neotype, redescribed the species, and showed that P. uncinata is a junior synonym of P. hoplura . Radashevsky et al. ( 2023b: 1) showed that “The history of the discovery of P. hoplura around the world appears to be intimately linked to global shipping commencing in the mid-19th century, followed by the advent of the global movement of commercial shellfish (especially the Pacific oyster Magallana gigas ) in the 20th century, interlaced with continued, complex dispersal by vessels and aquaculture.” Based on the analysis of available genetic data, they confirmed the conspecificity of the disjunct populations of P. hoplura around the world and tentatively proposed the Northwest Pacific, or at most the Indo-West Pacific, as the home region of this species, but called for further study of this hypothesis.

In the Americas, P. hoplura was first recorded (as P. uncinata ) boring into shells of the abalone Haliotis discus hannai Ino, 1953 cultivated in land tanks in Coquimbo, Chile ( Figure S6 ) (Radashevsky and Olivares, 2005 ). The abalones were imported from Japan to create a stalked colony and further cultivation in coastal waters. Therefore, Radashevsky and Olivares ( 2005 ) assumed that the shell-boring worms were unintentionally introduced to Chile along with abalones from Japan. Until 2019, there was no evidence that abalones grown in land tanks were ever released into the sea (Radashevsky et al., 2023b ).

The only other records of P. hoplura in the Americas were in São Paulo, Brazil, and California, USA, by Radashevsky and Migotto ( 2017 ) and Radashevsky et al. ( 2023b ) (Figure S6). In São Paulo, the worms were found in the stony coral Mussismilia hispida (Verrill, 1901) on Ilha de Alcatrazes in 1995 and in shells of the mangrove cupped oyster Crassostrea rhizophorae in the fouling of pier pilings on São Sebastião Island (Ilhabela) in 2015. Egg capsules with larvae were present in burrows in oyster on Ilhabela, indicating that environmental conditions are suitable for this harmful borer to establish itself in Brazil.

Polydora nuchalis Woodwick, 1953

Polydora nuchalis Woodwick, 1953: 381−383, Figure 1 ; 1960: 122−128, plates 1−3. Blake, 1981: 951−954, Figures 2C, D, 3; 1996: 171, Figure 4 .28I, J.

Material . MDBio-IB/UNICAMP (5); MNRJP 3310 (6); MZUSP 180 (1); SMF 13898 (1); UFBA (2); UFPE CPO 35, 42 (10).

Complete information on the holotype of P. nuchalis (California, Pacific USA) and specimens of this species from South America (Brazil) is given in Table S7 (mapped in Figure S7 ).

Habitat . Adults build silty tubes in soft sediments.

Diagnostic features . Prostomium blunt to weakly incised anteriorly. Caruncle extending to middle of chaetiger 3 (usually to the end of chaetiger 2). Cirriform occipital antenna present. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines simple, without any additional structure. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap.

Remarks . Polydora nuchalis was originally described based on two specimens from southern California ( Figure S7 ) (Woodwick, 1953 ). Woodwick ( 1960 ) described the reproduction and larval development of this species in California. Later, P. nuchalis was recorded from the Gulf of California, Mexico (Kudenov, 1975 ; Blake, 1981 , 1996 ) and tentatively identified in South Africa (Williams et al., 2017 ). It was also recorded from aquaculture ponds in Hawaii, where it could be introduced with the oysters (Bailey-Brock, 1990 ). Under natural conditions, P. nuchalis has always been found in tubes on the intertidal, occasionally forming dense settlements.

In South America, P. nuchalis was first recorded in Brazil, in the states of São Paulo (Pardo et al., 2005 ) and Paraná (Lana et al., 2006 ). Here, I report this species for the first time for the states of Rio de Janeiro, Bahia, and Pernambuco. No other record of P. nuchalis from South America has been reported to date. The conspecificity of disjunct populations of P. nuchalis in California and Brazil requires further study.

Polydora cf. rickettsi Woodwick, 1961

Polydora rickettsi Woodwick, 1961: 78–81, Figures 1–7. Blake, 1983: 257. Radashevsky and Cárdenas, 2004: 244–252, Figures 2–6. Radashevsky et al., 2006: 22−24. Delgado-Blas, 2009: 607, Figure 7 L. Diez et al., 2011: 3–5, Figures 2, 3.

Polydora cf. rickettsi: Sato-Okoshi and Takatsuka, 2001: 489–490, Figure 2 A–D.

Material . MZUSP (15).

Complete information on the holotype of P. rickettsi (Baja California Sur, Mexico) and specimens of presumably this species from South America (Argentina, Brazil, and Chile) is given in Table S8 (mapped in Figure S8 ).

Habitat . In South America, worms make U-shaped burrows in calcareous tubes of serpulid polychaetes, in mollusc shells and tests of barnacles, and occasionally in sponges. The habitat and presence of this species in Brazil remain uncertain.

Diagnostic features . Palps with narrow black lines on sides of frontal groove; black pigment diffused on lateral sides of prostomium, on peristomium, dorsal and ventral sides of 2−4 anterior characters, on up to 15 posterior chaetigers, and occasionally on pygidium; pigmentation partially or completely absent in some individuals. Prostomium anteriorly usually rounded and entire, occasionally blunt and weakly incised. Caruncle extending to end of chaetiger 4 (shorter in small individuals). Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a lateral tooth and a small subdistal longitudinal flange. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap. Spermatids joined in tetrads.

Remarks . Polydora rickettsi was originally described based on two specimens from a calcareous tube of the serpulid polychaete Spirobranchus incrassatus Krøyer in Mörch, 1863, collected from the low intertidal at Cape San Lucas, Baja California Sur, Mexico ( Figure S8 ) (Woodwick, 1961 ). Presumably, worms burrowed in these tubes.

In South America, P. rickettsi (or P. cf. rickettsi ) was widely reported from Chile ( Figure S8 ) boring into shells of the giant barnacle Austromegabalanus psittacus (Molina, 1782), keyhole limpets Fissurella maxima (Sowerby, 1834) and Fissurella nigra Lesson, 1831, slipper snails Crepipatella peruviana (Lamarck, 1822) and Crepipatella dilatata (Lamarck, 1822), turban snail Tegula atra (Lesson, 1831), Chilean abalone (loco) Concholepas concholepas (Bruguière, 1789), scallop Argopecten purpuratus (Lamarck, 1819), and commercial oysters Magallana gigas (Thunberg, 1793) and Ostrea chilensis Küster, 1844 (Blake, 1983 ; Sato-Okoshi and Takatsuka, 2001 ; Bertrán et al., 2005 ; Vargas et al., 2005 ; Moreno et al., 2006 ; Diez et al., 2020 ; Neill et al., 2020 ). Adult worms make U-shaped burrows inside shells. Sometimes there are dozens of worms in one shell. Occasionally, worms were found boring into a demosponge (Radashevsky and Cárdenas, 2004 ). The reproduction and larval development of this species was described from Corral Bay, southern Chile, by Radashevsky and Cárdenas ( 2004 ).

On the Atlantic coast of South America, Radashevsky et al. ( 2006 ) first reported P. rickettsi from Brazil (São Paulo) but noted that the origin of the examined specimens was uncertain. Thus, their identity needs to be verified in a further study. Later, the species was reported from northern Patagonia, Argentina ( Figure S8 ), boring into shells of four commercially important bivalves: scallop Aequipecten tehuelchus (d’Orbigny, 1842), clam Ameghinomya antiqua (P. P. King, 1832), ribbed mussel Aulacomya atra (Molina, 1782), Argentine flat oyster Ostrea puelchana d’Orbigny, 1842, and also in false jingle shell Pododesmus rudis (Broderip, 1834) (Diez et al., 2011 , 2013 , 2016 ). The infestation by P. rickettsi causes the formation of pearls in the ribbed mussel Aulacomya atra (Diez et al., 2016 ). The conspecificity of disjunct populations of P. rickettsi in Mexico and P. cf. rickettsi in South America requires further study.

Polydora nonatoi sp. nov.

https://zoobank.org/DB9B9CBD-4EA7-4EB5-B81D-B98387585801

Figures 1–2

Type material . Brazil, Rio de Janeiro, Sepetiba Bay, Ilha das Cabras, 22.945°S, 43.8634°W, coll. Carrerette, O. & da Silva, J.S.V., 20 Dec 2005, 0.5 m depth, MDBio-IB/UNICAMP 22907 ( holotype ), 22908 (247 paratypes), 16986 (20 paratypes); MIMB 44747 (5 paratypes), 44748 (8 paratypes), MIMB 44752 (53 paratypes); 7 m depth, MIMB 44749 (4 paratypes), MIMB 44750 (16 paratypes); 3 m depth, MIMB 44751 (30 paratypes).

Sepetiba Bay, Ilha Guaíba, 23.0075°S, 44.0297°W, coll. Carrerette, O. & da Silva, J.S.V., 20 Dec 2005, 0.5 m depth, MIMB 44747, 44748, 44752 (70 paratypes); 3 m depth, MDBio-IB/UNICAMP 16988 (11 paratypes), MIMB 44751 (30 paratypes); 7 m, MIMB 44749, 44750 (20 paratypes); Terminal Marítimo, 23.0108°S, 44.032°W, coll. Carrerette, O. & da Silva, J.S.V., 15 Sep 2006, 0.5-7 m depth, MDBio-IB/UNICAMP 16987 (14 paratypes).

Sepetiba Bay, Terminal de Minério (Porto de IItaguí), 22.9337°S, 43.832°W, coll. Carrerette, O. & da Silva, J.S.V., 15 Sep 2006, 0.5 m depth, MDBio-IB/UNICAMP 16989 (25 paratypes), MIMB 44763 (100 paratypes); 3 m depth, MDBio-IB/UNICAMP 16985 (31 paratypes); 7 m depth, MDBio-IB/UNICAMP 16990 (212 paratypes).

Guanabara Bay, Praia de Jurujuba, 22.9266°S, 43.1192°W, coll. Omena, E.P., Sep 2005, intertidal, MIMB 44746 (paratype).

Additional material . Brazil, Rio de Janeiro, Sepetiba Bay, Ilha das Cabras, MIMB 44757–44759 (249); Ilha Guaíba, MIMB 44760–44762 (95+); Terminal de Minério (Porto de IItaguí), MIMB 44763–44765 (250); Terminal Marítimo da Ilha Guaíba, MIMB 44766, 44767 (82).

Complete information on the type and other specimens of P. nonatoi sp. nov. from Rio de Janeiro, Brazil, is given in Table S9 (mapped in Figure S9 ).

Etymology . The species is named in honor of Edmundo Ferraz Nonato (1920–2014), a naturalist, oceanographer, professor, supervisor ( orientador ) of Paulo da Cunha Lana ( https://pt.wikipedia.org/wiki/Edmundo_Ferraz_Nonato ; Lana et al., 2017).

Diagnostic features . Palps with up to seven pairs of narrow stripes on sides of frontal groove; black narrow longitudinal stripes on lateral sides of anterior part of prostomium (in front of eyes); small paired black patches on dorsal side of peristomium and three anterior chaetigers. Prostomium incised anteriorly. Caruncle extending to end of chaetiger 3. Short occipital antenna present. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with large lateral tooth connected to main stem by thin sheath. Posterior notopodia with only capillary chaetae. Pygidium small, disc-like to cup-shaped, with middorsal gap. Spermatids joined in octads.

Adult morphology . Adults up to 15 mm long, 0.9 mm wide for 115 chaetigers. Intense black pigmentation comprising up to seven pairs of narrow stripes on sides of frontal groove of palps, stripes on anterior lateral sides of prostomium in front of eyes, and paired patches on dorsal side of peristomium and first three chaetigers ( Figure 1 A–D). Length of black stripes on palps variable; in some individuals extending over 1/5–1/4 of palp length ( Figure 1 A, B), occasionally as entire lines on sides of frontal groove.

Figure 1.
Adult morphology of Polydora nonatoi sp. nov. (Rio de Janeiro, Brazil). A, B, fragments of palps, showing paired black stripes on sides of frontal groove. C, anterior end, dorsal view, showing paired black spots on three anterior chaetigers, palps missing. D, anterior end, dorsal view, showing pigmentation on head and anterior chaetigers, palps missing. E, anterior end, ventral view, showing bilobed prostomium. F, anterior end, left lateral view, showing short triangular occipital antenna in anterior part of caruncle. G, posterior end, dorsal view, showing disc-like pygidium. H, right side of chaetigers 4–14, inner view, showing glandular pouches. I–K, methyl green staining: I, J, anterior ends, dorsal view; K, chaetigers 8–16, dorsal view. Abbreviations: an – occipital antenna; ch4–ch14 – chaetigers 4–14; gp – glandular pouches; pr – prostomium. Scale bars: A–C, F, I–K – 200 µm; D, E, G, H – 100 µm. A–K – formalin-fixed type specimens. A, B ,E, H – paratypes (MIMB 44752); C – holotype (MDBio-IB/UNICAMP 22907); D, F, G – paratypes (MDBio-IB/UNICAMP 22908); I–K – paratypes (MIMB 44748).

Prostomium anteriorly curved downward and incised ( Figure 1 D, E), posteriorly extending to end of chaetiger 3 as a low caruncle, shorter in small individuals. Distinct transverse furrow posteriorly from median eyes separating caruncle from middle part of prostomium. Anterior most part of caruncle relatively high, forming a short triangular occipital antenna ( Figure 1 F); in some individuals, antenna almost papillary. From one to four black eyes present or eyes absent; when present, eyes comprising one pair of median eyes and one pair of lateral eyes situated anteriorly and set wider apart. Palps as long as 10–20 chaetigers, with frontal longitudinal groove lined with fine cilia, latero-frontal motile compound cilia, and papillae with short non-motile cilia arranged on sides of frontal groove, and also scattered on lateral and abfrontal palp surfaces all along palp length.

Chaetiger 1 with short capillaries in neuropodia and short postchaetal lamellae in both rami; notochaetae absent. Posterior notopodia with only slender capillary chaetae.

Chaetiger 5 twice as large as chaetigers 4 and 6 ( Figure 1 C), with up to five dorsal superior capillaries ( Figure 2 C), seven falcate spines arranged in a slightly curved diagonal row and alternating with pennoned companion chaetae ( Figure 2 A–E), and seven ventral winged capillaries. Dorsal superior and ventral capillaries shorter and fewer than those on adjacent chaetigers. Falcate spines with large lateral tooth connected to main stem by thin sheath ( Figure 2 A, C); worn older spines in anterior part of row with lateral tooth broken, resembling flange ( Figure 2 B). In some individuals, falcate spines having small tooth and a small vertical flange above it ( Figure 2 D, E)

Hooded hooks in neuropodia from chaetiger 7, up to 10 in a series, not accompanied by capillaries. Hooks bidentate; shaft slightly curved, with weak constriction in upper part ( Figure 2 F, G).

Branchiae from chaetiger 7 almost to end of body, on first chaetiger slightly shorter then on chaetiger 8, full-sized from chaetigers 10−11 ( Figure 1 F), gradually diminishing in size along posterior half of body. Branchiae flattened, with surfaces oriented parallel to body axis, free from notopodial postchaetal lamellae, with longitudinal row of cilia along inner surface.

Pygidium small, thin, disc-like to cup-shaped with middorsal gap ( Figure 1 G).

Glandular pouches in neuropodia from chaetiger 7, large in chaetigers 7–9 and drastically smaller in succeeding chaetigers ( Figure 1 H).

Digestive tract without ventral buccal bulb and gizzard-like structure.

Nephridia from chaetiger 7 onwards; pairs of nephridia on each chaetiger opening to exterior dorsally via two separate nephridiopores.

Figure 2.
Adult morphology of Polydora nonatoi sp. nov. (Rio de Janeiro, Brazil). A–E, modified chaetae of chaetiger 5: A, B, D, E, lateral view; C, rear view. F, G, bidentate hooded hooks from neuropodia of middle chaetigers: F, frontal view; G, lateral view. Abbreviation: su – dorsal superior capillary chaetae. Scale bars: A–E – 20 µm; F, G – 10 µm. A–C, F, G – paratypes (MIMB 44752); D, E, paratypes (MIMB 44748).

MG staining. Intensely stained are the dorsal side of the prostomium in front of the eyes, dorsal side of the peristomium (the ventral side of the head is not stained), and small paired patches (gatherings of individual glandular cells) on the dorsal side from chaetigers 8–11 onwards ( Figure 1 I–K). The staining pattern was the same in specimens with chaetiger 5 falcate spines with large lateral tooth and specimens with falcate spines having small tooth and a small vertical flange above it.

Reproduction.Polydora nonatoi sp. nov. is dioecious. Gametes were present in both sexes from chaetigers 22–35 to chaetigers 41–90. In larger individuals, gametes start from more posterior chaetigers. Oogenesis is probably mainly intraovarian. Females collected in December 2005 contained numerous vitellogenic oocytes up to 80 µm in diameter. In males, spermatogonia proliferate in the testes; spermatogenesis occurs in the coelomic cavity. Spermatids were joined in octads. Spermatozoa were introsperm with a pointed acrosome, elongated nucleus and midpiece, and a long flagellum.

Figure 3.
Adult morphology and reproduction of Polydora paulolanai sp. nov. (Paraná, Brazil). A, complete worm in a burrow in oyster shell; middle part of the burrow filled with detritus. B, the same, anterior end, showing part of the egg capsule chain inside burrow and palps with narrow black line on sides of frontal groove; part of the inner detrital wall removed. C, anterior end, left lateral view, showing palp with five back bands. D, anterior end, left lateral view, palps missing. Abbreviations: an – occipital antenna; ca – egg capsules; ch5 – chaetiger 5; in – inner wall of the burrow composed of detritus accumulated between burrow branches; pa – palp. Scale bars: A – 500 µm; B–D – 200 µm. A–D – formalin-fixed paratypes (MIMB 44714).

Habitat . Adults of P. nonatoi sp. nov. live in silty-sand tubes in soft sediments in the state of Rio de Janeiro.

Remarks . Polydora species with black bands on the palps and an occipital antenna on the prostomium were reviewed by Radashevsky and Hsieh ( 2000: tables 1, 2). With these features, P. nonatoi sp. nov. is similar to P. hoplura , P. triglanda Radashevsky & Hsieh, 2000 , and P. paulolanai sp. nov. described below. However, P. nonatoi sp. nov. is different in that adults live in tubes in soft sediments, whereas the remaining species are either shell- or sponge-borers. Moreover, P. hoplura has heavy recurved spines, and P. paulolanai sp. nov. has needle-like spines in the posterior notopodia, whereas P. nonatoi sp. nov. has only capillary chaetae in the posterior notopodia. Same as P. triglanda , adults of P. nonatoi sp. nov. have large glandular pouches in the neuropodia of chaetigers 7–9 and drastically smaller pouches in subsequent chaetigers, and the spermatids joined in octads. However, the two species differ in that the falcate spines of chaetiger 5 of P. triglanda have a lateral flange, whereas the spines of P. nonatoi sp. nov. usually have a large lateral tooth. In addition, P. triglanda has wide black bands extending on the lateral sides of palps and lacks pigmentation on chaetigers, whereas P. nonatoi sp. nov. has very narrow black stripes on sides of the frontal groove of palps, as well as paired black spots on the dorsal side of 3–4 anterior chaetigers.

Among P. nonatoi sp. nov. with typical falcate spines of chaetiger 5 with a large lateral tooth ( Figure 2 A–C), there were few individuals with falcate spines having a small narrow lateral tooth and a small vertical flange above it ( Figure 2 D, E). The other morphological features of these worms were the same, including body size, the arrangement and size of the branchiae and oocytes, and MG staining. Therefore, I consider that these worms are conspecific, and the falcate spines with a small narrow lateral tooth and a small vertical flange above it are aberrant, when the lateral tooth was not developed normally, and the sheath, which connects the large lateral tooth with the main stem in normal spines, was partly developed and appears as a small thin vertical flange. Specimens with this kind of falcate spines are included in the type series of P. nonatoi sp. nov. but extracted (when possible) and registered separately (MIMB 44746–44749).

Polydora paulolanai sp. nov.

https://zoobank.org/015F8E73-10BC-43FF-A6DE-0ED313F30B43

Figures 3−6

Type material . Brazil, Paraná, Pontinha of Ilha do Mel, 25.561°S, 48.3179°W, intertidal, coll. Radashevsky, V.I., from sponge: 12 Nov 2001, MZUSP 183 ( holotype ), 185 (paratype); 5 Dec 2001, MZUSP 184 (2 paratypes); 14 Jul 2015, MIMB 44713 (10 paratypes); 25.8322°S, 48.5797°W, from shells of the cultivated oyster Crassostrea brasiliana (Lamarck, 1819): MMBV 44714 (11 paratypes).

Complete information on the type specimens of P. paulolanai sp. nov. from Paraná, Brazil, is given in Table S10 (mapped in Figure S10 ).

Etymology . The species is named in honor of Paulo da Cunha Lana (1956–2022), a biologist, ecologist, oceanographer, professor, and a great man ( https://pt.wikipedia.org/wiki/Paulo_da_Cunha_Lana ; https://www1.folha.uol.com.br/cotidiano/2022/07/mortes-cientista-do-mar-e-grande-nome-da-oceanografia-brasileira.shtml ).

Diagnostic features . Palps with narrow continuous (occasionally partially discontinuous) black lines or up to 10 distinct black bands on sides of frontal groove; small paired black patches on dorsal side of three anterior chaetigers (pigmentation partially or completely absent in some individuals). Prostomium incised anteriorly. Caruncle extending to end of chaetiger 3. Short occipital antenna present. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with transverse subdistal collar on concave side; part of collar on one side enlarged and appearing as a lateral flange or tooth. Posterior notopodia with numerous loosely held and greatly protruding out of body wall needle-like spines in addition to capillary chaetae. Pygidium small, cup-shaped to disc-like, with middorsal incision to gap. Spermatids joined in octads.

Adult morphology . Adults up to 15 mm long, 1 mm wide for 150 chaetigers ( Figure 3 A, B). Pigmentation on body and palps absent or paired patches of black pigment present on dorsal side of first three chaetigers in live individuals with less than 100 chaetigers ( Figure 4 A); in larger worms, black pigment usually present on palps either as a complete narrow band on sides of frontal groove ( Figure 3 B) or as distinct bands, up to 10 bands on each palp ( Figure 3 C). After fixation in formalin, golden pigment appearing on dorsal side of anterior and posterior chaetigers; few grains of this pigment sparsely scattered on anterior chaetigers ( Figure 5 A, C), while on posterior chaetigers these grains gathered in wide transverse bands ( Figure 6 A, B).

Figure 4.
Adult morphology of Polydora paulolanai sp. nov. (Paraná, Brazil). A, anterior end, dorsal view. B, posterior end, dorsal view. C, the same, left lateral view. D–G, modified chaetae of chaetiger 5: D, falcate spine and bilimbate-tipped companion chaeta, left lateral view; E, falcate spine, frontal view; F, ventral capillary chaeta; G, dorsal superior capillary chaeta. H, bidentate hooded hook from neuropodium of chaetiger 7. Scale bars: A – 300 µm; B, C – 200 µm; D–H – 30 µm. A – paratype (MZUSP 184); B, C – holotype (MZUSP 183); D–H – paratype (MIMB 44714).

Prostomium anteriorly incised, with two short round lobes, posteriorly extending to end of chaetiger 3 as a low caruncle (Figures 4A, 5A, C), shorter in small individuals. Short occipital antenna present on prostomium between palp bases (Figures 3D, 4A). From one to two pairs of black eyes present or eyes absent; when present, eyes comprising one pair of median eyes and one pair of lateral eyes situated anteriorly and set wider apart. Palps as long as 10–20 chaetigers, with frontal longitudinal groove lined with fine cilia, latero-frontal motile compound cilia, and papillae with short non-motile cilia arranged in 2–3 rows on sides of frontal groove, and also scattered on lateral and abfrontal palp surfaces all along palp length.

Chaetiger 1 with short capillaries in neuropodia and short postchaetal lamellae in both rami; notochaetae absent. Small individuals, usually with less than about 100 chaetigers, with only capillary chaetae in posterior notopodia; larger worms with numerous needle-like spines in addition to slender capillaries in notopodia of about 1/3 posterior part of body; spines loosely held in tufts and greatly protruding out of body wall (Figures 4B, C, 6A−C).

Chaetiger 5 twice as large as chaetigers 4 and 6, with up to six dorsal superior capillaries (Figures 4G, 5D, E), eight falcate spines arranged in a slightly curved diagonal row and alternating with pennoned companion chaetae (Figures 4D, 5D), and eight ventral winged capillaries (Figures 4F, 5E). Dorsal superior and ventral capillaries shorter and fewer than those on adjacent chaetigers. Falcate spines with transverse subdistal collar on concave side; part of collar on one side enlarged and appearing as a lateral flange or tooth (Figures 4D, E, 5D, E).

Hooded hooks in neuropodia from chaetiger 7, up to 10 in a series, not accompanied by capillaries. Hooks bidentate; shaft slightly curved, with weak constriction in upper part ( Figure 4 H).

Branchiae from chaetiger 7 almost to end of body, on first chaetiger shorter then on chaetiger 8 (Figures 3C, D, 4A), full-sized from chaetigers 10−11, gradually diminishing in size along posterior half of body. Branchiae flattened, with surfaces oriented parallel to body axis, free from notopodial postchaetal lamellae, with longitudinal row of cilia along inner surface.

Nototrochs from chaetigers 7–8 onwards, each composed of one row of short cilia in both sexes, on branchiate chaetigers extending onto branchiae. Intersegmental ciliation absent in both sexes.

Pygidium small, cup-shaped to disc-like, with dorsal gap to incision (Figures 4B, C, 6C).

Glandular pouches in neuropodia from chaetiger 7, large in chaetigers 7−9 and considerably smaller in succeeding chaetigers.

Digestive tract without ventral buccal bulb. Narrow esophagus extending through 12–16 chaetigers; its posterior part in 2−3 chaetigers with muscular wall, resembling gizzard-like structure.

Nephridia from chaetiger 7 onwards; pairs of nephridia on each chaetiger opening to exterior dorsally via two separate nephridiopores.

Figure 5.
Adult morphology of Polydora paulolanai sp. nov. (Paraná, Brazil). A–C, anterior ends stained with methyl green: A, C, dorsal view; B, ventral view. D, E, modified chaetae of chaetiger 5. Abbreviations: ch5 – chaetiger 5; co – bilimbate-tipped companion chaeta; fa – heavy falcate spines; su – dorsal superior capillary chaetae; ve – ventral capillary chaetae. Scale bars: A–C – 200 µm; D, E – 30 µm. A–E – paratypes (MIMB 44714).

MG staining. Intensely stained are the dorsal side of the prostomium in front of the eyes, the dorsal side of the peristomium (the ventral side of the head is not stained), and individual glandular cells on the dorsal side from chaetigers 9−11 onwards ( Figure 5 A, C). Some structures are also stained on the lateral and ventral sides of the four anterior chaetigers ( Figure 5 B). The staining pattern was the same in specimens from sponges and oyster shells.

Reproduction.Polydora paulolanai sp. nov. is dioecious. Paired gonads are attached to the segmental blood vessels in the middle chaetigers. Oogenesis is mainly intraovarian. Developed oocytes accumulate in the coelomic cavity prior to spawning. In males, spermatogonia proliferate in the testes; spermatogenesis occurs in the coelomic cavity. Spermatids are joined in octads. Spermatozoa are introsperm with a pointed acrosome, an elongated nucleus and midpiece, and a long flagellum.

Females lay eggs into transparent capsules, which join to each other in a string and each attach by two stalks to the inner wall of the burrow ( Figure 3 B). Up to 50 eggs were deposited in one capsule, and one female produced up to 50 capsules with about 2,000 eggs per brood; small females had smaller broods. The laid eggs were 105−110 μm in diameter, with smooth envelope less than 1 μm thick. Females brooding larvae in capsules had the next generation of vitellogenic oocytes developing in the ovaries. Most of the eggs in the broods developed into larvae. Egg capsules with trochophores were found in July 2015. The trochophores had several very small trochoblasts bearing short cilia of the prototroch, and one pair of rounded ventral ciliary patches. They had no eyes and moved inside the capsules due to active beating of the cilia of the ventral patches. The larvae had a small mouth and a short foregut lined with numerous short cilia. The posterior end of the foregut was joined to a spherical mass of large yolky endodermal macromeres, which occupied most of the inner space of the larvae. The lumen of the midgut, posterior gut, and anus were not yet developed. The duration of larval development inside capsules remains unknown; however, compared to other Polydora species producing similar broods (see Blake and Arnofsky, 1999), P. paulolanai sp. nov. larvae probably hatch after growing three chaetigers.

Figure 6.
Adult morphology of Polydora paulolanai sp. nov. (Paraná, Brazil). A, B, posterior chaetigers, dorsal view, showing pigment appeared after fixation in formalin. C, posterior end, rear view, showing small cup-shaped pygidium and needle-like spines loosely held in notopodia. Scale bars: A–C – 200 µm. A–C – formalin-fixed paratypes (MIMB 44714).

Habitat.Polydora paulolanai sp. nov. is an opportunistic borer in Paraná. Adults make branching burrows in sponges, as well as in shells of the oyster Crassostrea brasiliana (Lamarck, 1819) in the intertidal and shallow waters. The walls of the burrows are lined with detritus; the median space of each burrow is also filled with detritus, which forms a medial wall ( Figure 3 A, B). Each burrow opens to the outside via two joined apertures, forming a characteristic 8-shaped hollow in the shell, and continues with two smooth, silty tubes up to 5 mm long each. Boring in oysters, worms do not form shell blisters.

Remarks . Adults of P. paulolanai sp. nov. show high ontogenetic and individual variability of most diagnostic morphological characters. Caruncle length, body and palp pigmentation, and the presence of needle-like spines in the posterior notopodia are size-dependent and should be used with caution to identify specimens. The morphology of the heavy falcate spines from the notopodia of chaetiger 5 is stable and specific. Similar spines with a subdistal collar on the concave side are also present in two other sponge-boring Polydora species: P. colonia and P. spongicola . Whether these spines are a synapomorphy, inherited from the nearest common ancestor and marking a monophyletic group of species, will be studied in a future phylogenetic analysis of Polydora . These three species differ from each other by the presence/absence of modified spines in the posterior notopodia: P. spongicola has only slender capillary chaetae, while P. colonia has heavy recurved spines, and P. paulolanai sp. nov. has numerous needle-like spines in addition to capillary chaetae. Remarkably that P. colonia and P. spongicola are obligate sponge-borers, whereas P. paulolanai sp. nov. has been found in sponges and oyster shells. Worms boring in sponges and shells had the same morphology and the same MG staining pattern and are, therefore, considered conspecific.

Loose tufts of needle-like spines greatly protruding out of body wall, as in P. paulolanai sp. nov., are also present in Polydora fusca Radashevsky & Hsieh, 2000 and Polydora villosa Radashevsky & Hsieh, 2000 , both described from Taiwan, and in Polydora robi Williams, 2000 from the Philippines and Indonesia. However, none of these species bores in sponges: P. fusca inhabits mud tubes on soft bottoms; P. villosa bores in corals, while P. robi bores in shells of various molluscs. Polydora villosa is notable for the absence of occipital antenna, which is present in the other three species. Polydora paulolanai sp. nov. differs from P. fusca and P. robi in the presence of dorsal superior capillaries on chaetiger 5, which are absent in the latter two species. Polydora robi differs from other needle-bearing species by having an entire prostomium instead of a prostomium with an incision on the anterior margin. Polydora robi is unique among these species in having a pygidium surrounded by anal papillae without a cup-shaped or disk-like expansion.

Polydora cf. websteri Hartman in Loosanoff & Engle, 1943

Polydora websteri Hartman in Loosanoff & Engle, 1943: 70−72, Figure 1 . Blake, 1969: 10−16, Figures 5−10 (larval morphology); 1971 (Part.): 6−8, Figure 3 ; 1983: 257. Radashevsky, 1999: 110−112, Figure 1 . Read, 2010: 91−93, Figures 1H−J, 2B, 2D, 2F, 4D−G. Sato-Okoshi and Abe, 2013: 1280−1281, Figure 2 . Ye et al., 2017: 702−705, Figures 1, 2 (adult and larval morphology). Sato-Okoshi et al., 2023: 213, Figure 5 A, B.

Polydora cf. websteri: Barros et al., 2017: 4−11, Figures 2−5.

Material . MDBio-IB/UNICAMP 7436 (1).

Complete information on the lectotype of P. websteri (Connecticut, Atlantic USA) and specimens of presumably this species from South America (Brazil, Ecuador, and Peru) is given in Table S11 (mapped in Figure S11 ).

Diagnostic features . Palps with narrow continuous (occasionally partially discontinuous) black lines on sides of frontal groove; black pigment absent on body segments. Prostomium incised anteriorly. Caruncle extending to end of chaetiger 2 (occasionally to middle of chaetiger 3). Occipital antenna absent. Chaetiger 5 with dorsal superior and ventral capillaries; heavy falcate spines with a lateral flange. Posterior notopodia with only capillary chaetae. Pygidium small, cup-shaped to disc-like, with dorsal incision to gap.

Habitat . Adults make U-shaped burrows in the shells of bivalves (such as clams, scallops, and oysters), gastropods (such as cultured abalone and intertidal snails), barnacle tests, and coralline algae worldwide. In Brazil, worms of likely this species bore in shells of the mangrove oyster Crassostrea brasiliana (Lamarck, 1819).

Remarks . The specific name of Polydora websteri Hartman in Loosanoff & Engle, 1943 was proposed as a replacement for Polydora caeca Webster, 1879a , a junior secondary homonym of P. coeca (Örsted, 1843 ) (see the above Remarks on P. caeca ). However, c omparison of Webster’s description with Hartman’s material revealed that Webster and Hartman dealt with two different species (Radashevsky and Williams, 1998 ). Accordingly, the specific name P. websteri Hartman was conserved (not to be treated as a replacement for P. caeca [ICZN, 2001 ]), and a lectotype from Milford, Connecticut, USA, was designated for P. websteri (Radashevsky, 1999 ).

Polydora websteri is an opportunistic borer of various calcareous biogenic substrata, including shells of oysters and other commercially important molluscs (Blake and Evans, 1973 ). It has been widely reported all over the world and its biology and genetics have been studied in numerous investigations (e.g., Blake, 1969 , 1971 ; Ye et al., 2017 ; Cole et al., 2020 ; Martinelli et al., 2020 , 2024 ; Waser et al., 2020 ; Rodewald et al., 2021 ; Silverbrand et al., 2021 ; Sato-Okoshi et al., 2023 ; Davinack et al., 2024 ). Rice et al. ( 2018 ) compared COI sequences of P. websteri from the Atlantic and Gulf coasts of North America, as well as from Hawaii in the Pacific with available corresponding sequences for Asian samples. They found that sequence divergence was highest among the Asian haplotypes and that overall sequence diversity within and between populations of P. websteri was extremely limited. Therefore, Rice et al. ( 2018 ) suggested that P. websteri may be of Asian origin, and that the high levels of connectivity among populations of this species has been produced by human-mediated transport of commercial shellfish products or by shipping. A similar anthropogenic spread has been suggested for P. hoplura , Dipolydora giardi (Mesnil, 1893), some other shell-boring polydorins (Radashevsky et al., 2023b , b), and probably led to the widespread distribution of P. caeca (see above).

In South America, P. websteri was first reported from Peru and Ecuador by Blake ( 1983 ). Lana ( 1986 ) and Bolívar and Lana ( 1986 , 1988) reported this species from Paraná, Brazil. However, Brazilian specimens (MDBio-IB/UNICAMP 7003) were reexamined and referred to P. cf. haswelli by Radashevsky et al. ( 2006 ). Here, I refer those Brazilian specimens to P. caeca (see Remarks for P. caeca above). Polydora websteri has also been reported in various ecological studies in Argentina and Brazil. However, the worms obtained from most of these studies have not been deposited in museum collections, and their identification cannot currently be verified. Barros et al. ( 2017 ), for the first time, described and illustrated P. cf. websteri boring in shells of the mangrove oyster Crassostrea cf. brasiliana in Brazil (in two estuaries in the state of Pernambuco). Although morphological characteristics of these worms perfectly matched those of P. websteri , the authors suggested that the actual status of this species on the Brazilian coast should be clarified by genetic analysis. While it is quite plausible that P. websteri is present both in Argentina and Brazil, it can be confused with P. caeca or P. ecuadoriana: worms of the former species occasionally have discontinuous bands of black pigment on palps typical for P. caeca or P. ecuadoriana , while small individuals of the two latter species often have continuous line on the sides of the frontal groove of palps typical for P. websteri . This underscores the need for molecular analysis of shell-boring worms from the Atlantic coast of South America.

CONCLUSION

Correct identification of living creatures in one region or country often depends on earlier descriptions of similar creatures from a very distant place. Detailed initial characteristics are of decisive importance when it comes to identifying individuals from disjunct populations or a group of similar and even sibling, morphologically indistinguishable species. The problem of identification of shallow-water marine invertebrates arises from the fact that a large number of species were originally briefly described from European and North American waters and have never been subsequently redescribed. Brief descriptions of these species fit similar organisms worldwide and thus led to the strong believe that many species of marine invertebrates, especially polychaete annelids, were “naturally” cosmopolitan. Within this belief, polychaetes were considered morphologically variable and highly adaptive, with individuals of the same species showing the capacity of occupying different habitats. Detailed morphological studies coupled with molecular tools in recent decades have uncovered species groups among some previously recognized “cosmopolitans” (e.g., Radashevsky et al., 2014 ; Hutchings and Kupriyanova, 2018 ; Nygren et al., 2018 ; Simon et al., 2019 ), but many taxonomic puzzles are yet to be resolved. At the same time, many species have become and are becoming widespread, entering remote regions as a result of human displacement (e.g., Radashevsky et al., 2020 , 2022 , 2023b , 2023a ).

The identification of Polydora worms, as well as of many other polychaetes from South America, faces all the problems described above. Incomplete morphological descriptions and lack of molecular data for Polydora species originally described from distant places do not allow the correct identification of similar worms from South America. This study, in addition to describing new species, highlights specific issues that need to be addressed in the future.

ACKNOWLEDGMENTS

I first met Paulo Lana at the Polychaete Autecology International Course organized by Maria Cristina Gambi and Adriana Giangrande at the Laboratory of benthos of the Stazione Zoologica Anton Dorn on the island of Ischia in the Gulf of Naples, Italy, in July 1994. Later, Paulo invited me to attend the 6th International Polychaete Conference organized under his leadership in Curitiba, Paraná, Brazil, in August 1998. It was winter in Brazil, and for me (who grew up in the Urals and Siberia), it was my first experience of enduring such a strong cold indoors at night. However, this was fully compensated by the very warm and friendly atmosphere at the conference. When the Soviet Union collapsed and Russia, including the Russian Academy of Sciences, suffered greatly in the 1990s, Paulo invited me for an internship as a visiting professor ( professor visitante ) at the Centro de Estudos do Mar of the Federal University of Paraná, in Pontal do Sul, where he was the head of the Laboratory of benthos. The amazing instant friendly support, living and working conditions provided by Paulo and his family made this period 2000−2002 in Pontal do Sul and Curitiba one of the best in my life and the life of my family. The same support was provided later during my occasional visits to Curitiba and Pontal do Sul. Extraordinary intelligence, knowledge, exceptional sense of humor and charisma of Paulo made him one of the most brilliant people I have ever met in my life. My sincere eternal gratitude to Paulo for this meeting and the time spent together. Eterno grande abraço, meu querido amigo .

Additional material for this study was provided by Paulo Lana, Álvaro Migotto, Rosebel Nalesso, Karla Costa, João Nogueira, Elianne Omena, Theresinha Monteiro Absher, and Yasmine Neptune. Instant help and assistance were provided by Álvaro Migotto, Rosebel Nalesso, Cecília Amaral, Paulo Paiva, and Christine Ruta. Hedda Elisabeth Kolm and Milton organized field trips when the material of Polydora paulolanai sp. nov. was collected. Tatiana Menchini Steiner (MDBio-IB/UNICAMP), Marcelo Veronesi Fukuda (MZUSP), and Camila Messias (MNRJP) helped with museum collections. Nomenclatural issues and the taxonomic status of Polydora caeca , P. neocaeca , and P. haswelli were discussed with James A. Blake, Geoffrey B. Read, James T. Carlton, and Jason D. Williams. James A. Blake shared important memories of his research in Australia in 1977 and provided important information about the type specimens of P. haswelli . James T. Carlton edited and significantly improved some parts of the text. To all these colleagues and friends, I express my sincere gratitude. I am also grateful to two anonymous reviewers who provided valuable comments and important suggestions that improved the manuscript. Financial support to this study was provided by the Ministério da Educação do Brasil via the Universidade Federal do Paraná, Curitiba (Contract 125/2000).

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• 1
  Adults of some species in the Key usually have intense and very characteristic black pigmentation, which may include distinct bands or blotches on the palps, narrow black stripes on the anterior lateral sides of the prostomium, and paired spots on the dorsal side of the peristomium, and 2−4 anterior characters. However, the presence of these bands and spots is quite variable: some individuals may be missing some or even all of them. Therefore, pigmentation pattern is not included in the Key (except for the last two species) and is mentioned here only as a commentary.
• 2
  Observation and interpretation of the morphology of additional structures on the falcate spines of chaetiger 5 can be challenging due to their individual and ontogenetic variability. In older spines situated in the anterior part of the spine row, the lateral flange may be severely worn or damaged, resembling a small tooth. Therefore, these structures are best observed in younger spines situated in the posterior part of the spine row.

Edited by

• Associate Editor:
  Maikon Di Domenico

Publication Dates

• Publication in this collection
  29 Nov 2024
• Date of issue
  2024

History

• Received
  11 Sept 2023
• Accepted
  18 May 2024
• Corrected
  17 Dec 2024