Two non-indigenous species of Hippopodina (Bryozoa: Cheilostomatida) in the southwestern Atlantic: taxonomy and biogeographyABSTRACT
The taxonomic reassessment of Brazilian material previously assigned to Hippopodina feegeensis (Busk, 1884) revealed the occurrence of two distinct species in the southwestern Atlantic: H. feegeensis and Hippopodina similis Souto & Reverter-Gil, 2024. Specimens from artificial and natural substrates along the Brazilian coast were examined using stereomicroscopy and scanning electron microscopy (SEM), and compared with historical specimens from Ernst Marcus’ collection. The species are distinguishable by characters of the frontal pseudopores, primary orifice, avicularia, ooecium, and ancestrular complex. Hippopodina feegeensis appears restricted to artificial structures in northeastern Brazil, whereas H. similis occurs mainly in southeastern and southern Brazil on both artificial and natural substrates. The recurrent association of both species with harbors and other man-made structures, combined with their disjunct Atlantic distribution, supports their likely involvement in maritime-mediated bioinvasion processes. The clarification of species boundaries within the H. feegeensis complex refines the biogeographical understanding of the genus in the southwestern Atlantic and underscores the importance of accurate taxonomy for detecting and monitoring non-indigenous bryozoans along the Brazilian coast.
KEYWORDS
Bioinvasion; Brazil; Hippopodina feegeensis; Hippopodina similis
INTRODUCTION
The introduction and dispersal of non-indigenous (exotic) marine species are among the leading drivers of biodiversity loss and ecosystem disruption in coastal environments (Bax et al. 2003). This global phenomenon is strongly linked to human activities, particularly the expansion of international maritime trade (Carlton 1985, Ruiz et al. 1997). In addition to shipping, the proliferation of artificial substrates - such as wood, metals, concrete, and fiberglass - in urbanized coastal areas provides new habitats that enhance the colonization and establishment of fouling exotic species, further increasing the risk from biological invasions (Tyrrell and Byers 2007, Xavier et al. 2023, Bettim et al. 2025). Given Brazil’s extensive coastline and high volume of shipping traffic, exotic marine species are of great concern (Lopes 2009).
Bryozoans, along with other sessile marine taxa such as barnacles, mussels, hydroids, and algae, are frequently reported to be involved in biological invasions (Costello et al. 2026). These colonial sessile animals grow on a variety of substrates and have a high potential to adapt quickly, facilitating their establishment in artificial environments (Gordon and Mawatari 1992, Miranda et al. 2018).
On the Brazilian coast, studies on exotic and invasive species have increased over the past decade, alongside new taxonomic research. In the first comprehensive review of marine exotic bryozoans in Brazil, twelve species were reported (Miranda et al. 2018). Subsequent ecological studies on marine fouling enabled the reassessment of Schizoporella errata (Waters, 1878), previously considered a cryptogenic species, as invasive. Three additional exotic species - Buskia socialis Hincks, 1886, Conopeum reticulum (Linnaeus, 1767), and Scruparia ambigua (d’Orbigny, 1841) - have been detected on various artificial piers along the Brazilian coast (Miranda et al. 2018, Xavier et al. 2021). Over the past five years, new exotic and invasive bryozoans have been recorded, including Amathia alternata Lamouroux, 1816, which has affected human livelihoods and promoted the accumulation of drift organisms on the southern and southeastern coasts of Brazil (Nascimento et al. 2022, Tocci et al. 2022), and Parasmittina longirostrata Liu in Liu, Yin & Ma, 2001 (Farias et al. 2024). To date, at least 18 exotic marine bryozoans have been reported along the Brazilian coast, with a single Hippopodina species recorded as exotic: Hippopodina tahitiensis (Leca & d’Hondt, 1993) (Lopes 2009, Miranda et al. 2018, Teixeira and Creed 2020).
HippopodinaLevinsen, 1909 comprises 21 species (Bock 2024), four of which have been reported in Brazil: Hippopodina feegeensis (Busk, 1884), Hippopodina inarmata (Almeida, Larré & Vieira, 2021), Hippopodina pulcherrima (Canu & Bassler, 1928), and Hippopodina tahitiensis (Leca & d’Hondt, 1993). Among these, Hippopodina feegeensis has been widely reported as having a circumtropical distribution (Tilbrook 1999, 2006). Recent studies, however, indicate that this name may encompass multiple species, such as Hippopodina similis Souto & Reverter-Gil, 2024, described from the Iberian Peninsula (Souto and Reverter-Gil 2024) and subsequently reported from the Canary Islands (Ruiz-Velasco et al. 2025). In Brazil, H. feegeensis has been recorded from São Paulo (Marcus 1937, Migotto et al. 2011, Marques et al. 2013), Pernambuco, and Bahia (Miranda et al. 2018). Nevertheless, Rocha et al. (2013) suggested that the Brazilian material may represent a distinct species, and thus H. feegeensis is considered part of a species complex requiring further taxonomic investigation (Miranda et al. 2018).
This study aims to evaluate the Hippopodina feegeensis species complex from the Brazilian coast through morphological analyses, clarifying species boundaries and reassessing the taxonomic identity of Brazilian material.
MATERIAL AND METHODS
Part of the material examined (Fig. 1) was collected from artificial structures using spatulas at several harbor and marina sites along the Brazilian coast, including the Port of Cabedelo (Paraíba), the Port of Suape (Pernambuco), and the Espírito Santo Yacht Club (Espírito Santo). Specimens from the Recifes Artificiais Marinhos (on the Paraná Continental Shelf) were sampled using Autonomous Reef Monitoring Structures (ARMS; Jessop 2026) deployed as part of the REBIMAR (Programa de Recuperação da Biodiversidade Marinha) project, with specimens donated by Rafael Metri. Specimens from the Ponta do Poço Marina Clube, near the entrance of the Paranaguá Estuarine Complex (Pontal do Paraná, Paraná), were collected from experimental polyethylene plates. Samples from natural substrates were obtained exclusively by scuba diving in São Sebastião, São Paulo. Specimens were deposited in the bryozoan collection of the Museu de Zoologia, Universidade Federal de Pernambuco, Brazil (UFPE). Historical specimens from Ernst Marcus’ collection are deposited in the bryozoan collection of the Museu de Zoologia, Universidade de São Paulo, Brazil (MZUSP).
Sampling localities of examined Hippopodina specimens in Brazil: Paraíba (PB), Pernambuco (PE), Bahia (BA), Espírito Santo (ES), São Paulo (SP), and Paraná (PR). Symbols: black square, Hippopodina feegeensis; black triangle, Hippopodina similis.
Samples were preserved in 70% ethanol and analyzed under a stereomicroscope for identification using relevant literature (Tilbrook 1999, 2006, Souto and Reverter-Gil 2024). Selected colonies were prepared for scanning electron microscopy (SEM). Organic tissues were removed using sodium hypochlorite at different concentrations and exposure times, and the colonial surfaces were subsequently cleaned in an ultrasonic bath for 10 s. Cleaned materials were mounted on stubs and examined using backscattered electron (BSE) imaging with a Hitachi TM4000Plus II at the Laboratório Avançado de Microscopia e Imagem (LAMI), Núcleo de Prospecção e Gestão da Biodiversidade do Nordeste (NPGBio), Universidade Federal de Pernambuco (UFPE). Zooidal measurements were taken from digital SEM images using ImageJ software (https://imagej.net/ij/download.html).
TAXONOMY
Hippopodina feegeensis ( Busk, 1884 )
Lepralia feegeensisBusk 1884: 144, pl. 22, fig. 9.
? Hippopodina feegeensis: Marcus 1939: 114.
Hippopodina feegeensis: Tilbrook 1999: 451, fig. 1a-f. (cum syn.).
Hippopodina feegeensis: Miranda et al. 2018: 5, Appendix A, p. 7 (in part).
Hippopodina feegeensis: Xavier et al. 2021: 5, table 1 (in part).
Hippopodina feegeensis, Pernambuco, Brazil, UFPE 3605: (A) colony showing zooids with and without avicularia; (B) close-up of autozooids; (C) close-up of a primary orifice with operculum and a distal avicularium; (D) close-up of a primary orifice with minute lateral condyles; (E) close-up of two ovicelled zooids showing dimorphic orifices; (F) tetrad ancestrular complex; note the small avicularia distal to the orifices. Scale bars: A = 1000 µm, B, E, F = 500 µm, C, D = 100 µm.
Description. Colonies reddish in life, pale cream in alcohol, encrusting, unilaminar, growing on artificial substrates. Autozooids arranged in regular linear series (Fig. 2A), becoming irregularly organized where growth occurs over uneven surfaces. Autozooids rectangular (Fig. 2B) (0.900-1.100 mm long, 0.650-0.750 mm wide), delimited by distinct sutures formed by raised walls. Frontal shield slightly convex, perforated by numerous small circular pseudopores with raised rims, absent around the orificial area; the arrangement of pseudopores imparts a distinctly tuberculate appearance to the frontal surface. Primary orifice (Fig. 2C, D) hoof-shaped (0.240-0.270 mm long, 0.240-0.260 mm wide); anterior margin rounded, occupying most of the orificial area, and separated from the shallow poster by a small rounded indentation; proximal rim of orifice nearly straight to arcuate; condyles minute, paired, triangular, and hooked downward. Adventitious avicularia (0.265-0.360 mm long) often present, single or paired, positioned distolaterally to the orifice (Fig. 2C); rostrum acutely triangular, slightly raised distally, medially directed; crossbar complete, lacking a columella. Ovicell (Fig. 2E) hyperstomial to slightly submersed in frontal wall of the distal autozooid, globular to elongate (0.770-0.790 mm long and 0.790-0.815 mm wide), closed by the operculum of maternal zooid; ooecium with numerous small funnel-shaped circular pseudopores (>200 pseudopores). Orifice of ovicellate zooids slightly shorter and wider than non-ovicellate zooids. Tetrad ancestrular complex (Fig. 2F); each ancestrular zooid with a distolateral avicularium.
Material examined. Brazil, PB: Port of Cabedelo, E.A. Xavier col., 27 Sep 2019, UFPE 335; PE: Ipojuca, Porto de Suape, 8°23’52.6”S, 34°57’13.3”W, E.A. Xavier col., 22 May 2023, UFPE 3605.
Additional comparative material (indeterminate). Brazil, PE: Barra de Sirinhaém, Sirinhaém [labelled as Recife, but according to Marcus (1939), collected in Barra de Serinhaem, Recife (sic)], [Otto Schubart leg.], [Ernst Marcus collection] balsam slide n. 965, MZUSP 1784.
Remarks. Hippopodina feegeensis has been reported from tropical to subtropical waters worldwide. The type material, collected by the H.M.S. Challenger expedition from the Philippines, was figured and redescribed by Tilbrook (1999), who regarded this species as a senior synonym of Cosciniopsis fallax Canu & Bassler, 1929. Later, Tilbrook (2006) noted morphological variation within material attributed to H. feegeensis and recognized a second species, Hippopodina adunca Tilbrook, 2006. Hippopodina adunca differs from H. feegeensis in having zooidal orifices with more pronounced lateral indentations, a poster of similar width to the anter (poster approximately 80% the width of the anter in H. feegeensis), avicularia with a setiform mandible (versus elongate-triangular in H. feegeensis), and a triad ancestrular complex (versus a tetrad ancestrular complex in H. feegeensis). Despite the presence of distal avicularia on zooids of the tetrad ancestrular complex in specimens from Pernambuco and Paraíba (northeastern Brazil), no morphological differences from the type material were detected, and they are herein assigned to H. feegeensis.
Historical specimens of H. feegeensis were reported from Brazil in the 20th century by Ernst Marcus: Santos Bay (São Paulo; Marcus 1937) and Sirinhaém (Pernambuco; Marcus 1939). Tilbrook (1999) reassigned Marcus’s material to two distinct species: Hippopodina pulcherrima (Canu & Bassler, 1928) and Hippopodina viriosa Tilbrook, 1999 [= Hippopodina tahitiensis (Leca & d’Hondt, 1993)]. Based on Marcus’s (1937) description and figures, particularly the presence of distolateral avicularia with an elongate, distomedially directed mandible, the material from Brazil is unlikely to correspond to H. tahitiensis, which has short, distally directed avicularia (Leca and d’Hondt 1993, Tilbrook 1999), or to H. pulcherrima, which has long and proximally directed avicularia (Canu and Bassler 1928), and is instead more consistent with H. similis or H. feegeensis. Marcus (1937) described both uniporous and multiporous septula on the vertical lateral walls of specimens from Santos, in contrast to the exclusively uniporous condition reported by Levinsen (1909) for H. feegeensis; the same structure has also been observed in Hippopodina similis Souto & Reverter-Gil, 2024. Additionally, comparisons with more recent material from Paraná and São Paulo - including specimens reported by Oricchio et al. 2019 as H. feegeensis -, as well as from Espírito Santo, indicate that the specimens examined here from southern and southeastern Brazil are conspecific and morphologically similar to H. similis (see below). Additional support comes from specimens from São Sebastião (approximately 100 km north of Santos, São Paulo), which exhibit 26-27 tentacles and occur on natural substrates, further suggesting that Marcus’s (1937) material from Santos belongs to H. similis (see below). Notably, the number of tentacles in H. feegeensis remains unknown, preventing a direct comparison based on this character.
The material from Sirinhaém (Pernambuco) reported by Marcus (1939) comprises fragments with few zooids mounted on a poorly preserved balsam slide (MZUSP 1784). In that fragment, the presence of avicularia cannot be determined with precision. However, this specimen is morphologically similar to H. feegeensis in having zooidal orifices with small rounded indentations, a proximal rim nearly straight, and a poster slightly narrower than the anter. There are, however, two interzooidal-like structures not known in any Hippopodina species, which prevents determination of the taxonomic identity of the Sirinhaém specimens.
Xavier et al. (2021) reported H. feegeensis from Paraíba (Cabedelo Harbor) and Espírito Santo (Espírito Santo Yacht Club); however, only the former record represents a correct identification of H. feegeensis, whereas the latter is a misidentification corresponding to H. similis (see below). Specimens from Jamaica reported as H. feegeensis by Winston and Jackson (2021) have relatively smaller orifices (0.198-0.252 mm long, 0.216-0.234 mm wide) compared with the type material and Brazilian specimens, and may not belong to H. feegeensis; taxonomic revision is therefore warranted.
Hippopodina similis Souto & Reverter-Gil, 2024
Hippopodina feegeensis: Marcus 1937: 116, pl. XXIII, fig. 62A, B.
Hippopodina feegeensis: Marques et al. 2013: 271.
Hippopodina feegeensis: Miranda et al. 2018: 5, Appendix A, p. 7 (in part).
Hippopodina feegeensis: Oricchio et al. 2019: 887.
Hippopodina feegeensis: Xavier et al. 2021: 5, table 1 (in part).
Hippopodina sp.: Ulman et al. 2017: 16, fig. S2B.
Hippopodina similisSouto & Reverter-Gil 2024: 11, fig. 7.
Hippopodina similis: Ruiz-Velasco et al. 2025: 33, fig. 16.
Hippopodina similis. (A-E) Espírito Santo, Brazil, UFPE 3630.1: (A) colony showing zooids with and without ovicells; (B) close-up of autozooids; note the small frontal adventitious avicularium; (C) close-up of autozooids with one or two distal avicularia; (D) close-up of a primary orifice with minute lateral condyles and a distal avicularium; (E) close-up of a distal area of an ovicelled zooid; (F) Paraná, Brazil (uncatalogued specimen): triad ancestrular complex; note the lack of avicularia. Scale bars: A-C = 500 µm, D = 100 µm, E = 200 µm, F = 1000 µm.
Description. Colonies reddish in life, pale cream in alcohol, encrusting, unilaminar, growing on artificial substrates. Autozooids arranged regularly in linear series (Fig. 3A, B), becoming irregularly organized where growth occurs over uneven surfaces. Autozooids almost rectangular to polygonal (Fig. 3C) (0.720-1.200 mm long, 0.375-0.650 mm wide), separated by distinct sutures between raised walls. Frontal shield slightly convex, with a faintly raised rim around the orifice; zooidal surface generally smooth but may become slightly tuberculate, perforated by numerous pseudopores except around the orificial area; pseudopores are often funnel-shaped, particularly near the zooidal margin. Primary orifice (Fig. 3D) almost hoof-shaped (0.215-0.245 mm long, 0.205-0.240 mm wide); anter margin rounded, occupying most of the orificial area, and separated from the shallow poster (0.050-0.070 mm long) by a rounded indentation; proximal rim of orifice nearly straight; condyles minute, paired, subtriangular, and hooked downward. Adventitious avicularia (0.150-0.230 mm long) often absent, but may be single or paired, positioned distolaterally to the orifice (Fig. 3C, D); rostrum triangular, slightly raised distally, medially or distomedially directed (in cases where two zooids are budded from a maternal zooid); crossbar complete, lacking a columella. A frontal avicularium may be present on the frontal shield (Fig. 3B), with a triangular rostrum proximally directed. Ovicell (Fig. 3E) hyperstomial to slightly submersed in frontal wall of the distal autozooid, globular to elongate (0.540-0.620 mm long and 0.450-0.580 mm wide), closed by the operculum of the maternal zooid; ooecium with large funnel-shaped pseudopores (<100 pseudopores), ranging from rounded to slit-like, often smaller and densely packed across the central surface. Orifice of ovicellate zooids slightly shorter than that of non-ovicellate zooids. Triad ancestrular complex (Fig. 3F); ancestrular zooids lacking avicularia. Lophophore with 26-27 tentacles.
Material examined. Brazil, BA: Salvador, Marina Mercado Modelo, 12°58’19”S, 38°30’56”W, Mar 2012, I.M. Neves leg., UFPE 552.1; UFPE 553.5; UFPE 554.5; ES: Vitória, Espírito Santo Yacht Club, 20°17’56.3”S, 40°17’24.1”W, 31 Mar 2017, L.M. Vieira leg., UFPE 3630.1; SP: São Sebastião, Baleeiro, 2 Dec 2013, L.M. Vieira col., UFPE 3732.2; Santos, [Ernst Marcus collection] balsam slide n. 485, MZUSP 1821; slide 985, MZUSP 1822; Ilhabela, Ilhabela Yacht Club, 23°46’27”S, 45°21’20”W, 03 May 2010, RAS, MZUSP (uncatalogued specimen); PR: Recifes Artificiais Marinhos, REBIMAR col., 25-27 m, ARMS BC 8T 001, UFPE 280; ARMS BB 1B 005, UFPE 282; ARMS BB 3B 001, UFPE 284; ARMS BC 6T 001, UFPE 277; ARMS BB 2B 002, UFPE 304; ARMS BB 7B 001, UFPE 309; Pontal do Paraná, Ponta do Poço Marina Clube, 25°32’58”S, 48°23’21”W, 04 Jun 2018, UFPE 3926.
Remarks. Souto and Reverter-Gil (2024) described Hippopodina similis from the Bay of Cadiz (South Iberian Peninsula), occurring on floating pontoons. Hippopodina similis has also been reported from the Canary Islands (Ruiz-Velasco et al. 2025). The species is characterized by a densely pseudoporous frontal surface, while the periorificial area remains devoid of pseudopores. No morphological differences were observed between the specimens studied here and those identified as Hippopodina sp. from Setur Finike Marina, Turkey (Ulman et al. 2017).
The Brazilian material examined from Bahia (NE Brazil), Espírito Santo and São Paulo (SE Brazil), and Paraná (S Brazil) is morphologically identical to the Iberian specimens. Additionally, we report zooids with a frontal avicularium (Fig. 3B), not previously described for this species. The Brazilian specimens have a triad ancestrular complex, similar to H. iririkiensis Tilbrook, 1999 and H. adunca Tilbrook, 2006. These two species can be distinguished from H. similis by the shape of the avicularia: in H. iririkiensis, the avicularia are shorter and laterally positioned compared with those of H. similis, whereas in H. adunca the avicularia are large, with setiform and hooked mandibles.
The material of H. similis from São Sebastião (São Paulo) is characterized by autozooids with 26-27 tentacles, consistent with that reported by Marcus (1937) for the material from Santos (São Paulo), originally identified as H. feegeensis. The morphological features and illustrations provided by Marcus (1937), together with the reexamination of the original specimens deposited at MZUSP, indicate that his specimens correspond to H. similis.
Hippopodina similis can be readily distinguished from H. feegeensis by several morphological characters: (i) the frontal pseudopores are funnel-shaped in H. similis, whereas they are small, circular, and surrounded by raised rims that impart a tuberculate appearance in H. feegeensis; (ii) the poster of the primary orifice has approximately the same width as the anter in H. similis, but approximately 80% of the anter width in H. feegeensis; (iii) the avicularia are shorter in H. similis than in H. feegeensis; (iv) the ooecial surface in H. similis bears fewer but larger pseudopores compared with the more numerous and smaller pseudopores of H. feegeensis; (v) the colony originates from a triad ancestrula in H. similis, whereas it arises from a tetrad ancestrula in H. feegeensis.
DISCUSSION
The taxonomic reassessment of Brazilian records attributed to H. feegeensis reveals that two distinct species occur along the southwestern Atlantic coast: H. feegeensis and H. similis. This finding reinforces the previous suggestion by Rocha et al. (2013) that H. feegeensis represents a species complex rather than a single, circumtropically distributed taxon. At the same time, the recognition of these two species in Brazilian waters highlights the need for careful morphological reassessment of historical records and refines the biogeographical understanding of the genus in the southwestern Atlantic. Accordingly, H. feegeensis appears to have a more restricted geographic distribution, associated exclusively with artificial structures in the Northeastern Brazil ecoregion (sensu Spalding et al. 2007; Paraíba to Pernambuco), whereas H. similis extends into the Eastern Brazil ecoregion (sensu Spalding et al. 2007; Bahia to Paraná), occurring in both natural and artificial habitats.
The comparative analysis of extant species of Hippopodina (Table 1) highlights the taxonomic relevance of ancestrular morphology and characters of the orificial and adventitious avicularia; however, fine-scale morphometric analyses of the orifice, avicularia, and ovicell are strongly recommended for accurate species delimitation among morphologically related taxa (not assessed in Table 1). Hippopodina pectoralis Harmer, 1957, described from deep waters of Indonesia (Harmer 1957), stands out markedly from the remaining species of Hippopodina by having a tatiform ancestrula and lateral pseudopores. This combination of characters is atypical for Hippopodina and is absent in the genotype, Lepralia feegeensis Busk, 1884, suggesting that H. pectoralis is not congeneric with Hippopodina and may instead belong to Hippothyris Osburn, 1952 (Osburn 1952). Its current placement therefore requires a detailed re-examination of type material.
Tabular identification key to extant species of Hippopodina: absent (-), bilaminate colony (bil), encrusting colony (enc), downcurved (dc), distomedially directed (dm), medially directed (me), proximally directed (pr), proximomedially directed (pm), unknown states (?). Species morphology according to Almeida et al. (2021), Busk (1884), Canu and Bassler (1928), Gontar (1993), Harmer (1957), Hayward (1974), Lagaaij (1963), Leca and d’Hondt (1993), Osburn (1940), Souto and Reverter-Gil (2024), Tilbrook (1999, 2006), and Winston and Jackson (2021).
Hippopodina similis and H. feegeensis can be reliably distinguished by a suite of characters best resolved using SEM, including the morphology and distribution of frontal pseudopores, the relative proportions of the anter and poster of the primary orifice, the size and shape of adventitious avicularia, and the structure of the ooecium. The morphology of the ancestrular complex (triad ancestrula in H. similis and tetrad ancestrula in H. feegeensis) represents one of the main diagnostic characters that can be readily recognized under a stereomicroscope without the need for SEM. However, because the vast majority of colonies lack preserved ancestrulae - a character also missing from the original description of H. similis (Souto and Reverter-Gil 2024) - this feature is often unavailable. Consequently, reliance on stereomicroscopy alone hampers accurate species identification and likely explains why Hippopodina species have been repeatedly misidentified in the literature.
From a biogeographical perspective, the occurrence of H. feegeensis in northeastern Brazil suggests a non-indigenous status in Brazilian waters. This interpretation is supported by the frequent association of H. feegeensis with artificial substrates, particularly in port areas such as Cabedelo (Paraíba) and Suape (Pernambuco), which are commonly linked to dispersal via maritime traffic and biofouling. Despite the exotic status of H. feegeensis in Brazil, the origin of this species remains unclear owing to its problematic taxonomy (Tilbrook 1999) and widespread occurrence in tropical to subtropical waters worldwide (Tilbrook 1999, Souto and Reverter-Gil 2024).
The earliest confirmed record of H. similis in Brazil, however, presents a biogeographical puzzle, particularly given that recent studies indicate a predominance of this species in fouling communities on artificial substrates (Vieira et al. 2015, Marques et al. 2013, Miranda et al. 2018, Oricchio et al. 2019, Xavier et al. 2021). Specimens from Santos Bay (Marcus 1937), originally collected at praia do Gois [sic] (= Góes Beach, Guarujá, São Paulo), represent the earliest confirmed record of Hippopodina similis. This area is located at the entrance to the Port of Santos, one of the major ports in South America (Kaluza et al. 2010), and may represent a potential point of entry or source of dispersal of this species. Within Brazil, the disjunct occurrence of H. similis in artificial habitats in Bahia (Marina Mercado Modelo, Salvador), Espírito Santo (Espírito Santo Yacht Club, Vitória), São Paulo (Ilhabela Yacht Club, São Sebastião), and Paraná (Ponta do Poço Marina Club) suggests the possibility of secondary spread along the coastline via recreational boats and local maritime traffic. Given the lack of genetic population studies on H. similis, this species is here classified as cryptogenic. The co-occurrence of H. feegeensis and H. similis in artificial habitats in Brazil and their similar morphology further complicate detection and emphasize the role of accurate taxonomy in disentangling native from non-indigenous components of local faunas.
ACKNOWLEDGMENTS
We thank Andrea Desiderato and Camilla Fellipe for deploying and retrieving the plate sets at Ponta do Poço Marina Clube during their doctoral project, and Camila M. Santos for assistance in searching for and photographing Hippopodina on the Ponta do Poço plates at UFPR. We thank the administrators and staff of the marina for permitting installation of the plate sets on the floating structures, and the authorities and staff of the Port of Cabedelo (Paraíba), the Port of Suape (Pernambuco), and the Espírito Santo Yacht Club (Espírito Santo) for granting permission for sampling. We thank Rafael Metri and REBIMAR for donating samples from Autonomous Reef Monitoring Structures, Isabela Monteiro Neves and Rosana M. da Rocha for donating samples from Bahia, and Marcelo V. Fukuda for providing data and images of the historical specimens from the Ernst Marcus collection at MZUSP. We also thank Roberto G. de S. Berlinck, Rosana M. da Rocha, Everthon A. Xavier, and Ana Carolina S. de Almeida for fieldwork assistance. Access to the SEM facilities at the Laboratório Avançado de Microscopia e Imagem, Núcleo de Prospecção e Gestão da Biodiversidade do Nordeste (NPGBio), Universidade Federal de Pernambuco (LAMI-UFPE) was provided by the Museu de Zoologia, Departamento de Zoologia, UFPE.
Data Availability Statement
All data generated and/or analyzed are included in this article.
LITERATURE CITED
-
Almeida AC, Larré IR, Vieira LM (2021) Ten new species of marine bryozoans (Gymnolaemata: Cheilostomatida) from Brazil. Zootaxa 5048(4): 511-537. https://doi.org/10.11646/zootaxa.5048.4.3
» https://doi.org/10.11646/zootaxa.5048.4.3 -
Bax N, Williamson A, Aguero M, Gonzalez E, Geeves W (2003) Marine invasive alien species: a threat to global biodiversity. Marine Policy 27(4): 313-323. https://doi.org/10.1016/S0308-597X(03)00041-1
» https://doi.org/10.1016/S0308-597X(03)00041-1 -
Bettim AL, Marochi MZ, Haddad MA (2025) Is the biofouling community of a subtropical estuary resistant to the recruitment of an exotic hydroid? Estuarine, Coastal and Shelf Science 313: 109120. https://doi.org/10.1016/j.ecss.2024.109120
» https://doi.org/10.1016/j.ecss.2024.109120 -
Bock PE (2024) Hippopodina Levinsen, 1909. In: Recent and fossil Bryozoa. Bryozoa Home age. http://www.bryozoa.net [Accessed: 11/02/2026]
» http://www.bryozoa.net - Busk G (1884) Report on the Polyzoa collected by H.M.S. Challenger during the years 1873-1876. Part 1. The Cheilostomata. Report on the Scientific Results of the Voyage of the H.M.S. “Challenger”. Zoology 10: 1-216.
- Canu F, Bassler RS (1928) Bryozoaires du Brésil. Bulletin de la Société des Sciences de Seine-et-Oise 9: 58-110.
- Carlton JT (1985) Transoceanic and interoceanic dispersal of coastal marine organisms: The biology of ballast water. Oceanography and Marine Biology: An Annual Review 23: 313-371.
-
Costello MJ, Ahyong S, Bieler R, Boudouresque C, Desiderato A, et al. (2026) World Register of Introduced Marine Species (WRiMS). https://doi.org/10.14284/347
» https://doi.org/10.14284/347 -
Farias J, Vieira LM, Almeida ACS (2024) Revealing the diversity of Parasmittina Osburn, 1952 (Bryozoa, Cheilostomatida) from the Southwest Atlantic: Species complexes, non-native and new species. PLOS One 19(8): e0304347. https://doi.org/10.1371/journal.pone.0304347
» https://doi.org/10.1371/journal.pone.0304347 - Gontar VI (1993) New deepwater species of Cheilostomida from the Kuril Islands and the Pacific Ocean (Bryozoa). Zoosystematica Rossica 2: 41-45.
- Gordon DP, Mawatari SF (1992) Atlas of Marine-fouling Bryozoa of New Zealand Ports and Harbours. Miscellaneous Publication New Zealand Oceanographic Institute 107(1): 1-52.
- Harmer SF (1957) The Polyzoa of the Siboga Expedition. Part 4. Cheilostomata Ascophora II. Siboga Expedition Reports 28d: 641-1147.
-
Hayward PJ (1974) Studies on the cheilostome bryozoan fauna of the Aegean island of Chios. Journal of Natural History 8(4): 369-402. https://doi.org/10.1080/00222937400770321
» https://doi.org/10.1080/00222937400770321 -
Jessop A, Steyaert M, Daraghmeh N, Pagnier J, Clark MS, et al. (2026) A review of autonomous reef monitoring structures (ARMS) for monitoring hard-bottom benthic biodiversity. Methods in Ecology and Evolution 17(2): 435-455. https://doi.org/10.1111/2041-210x.70194
» https://doi.org/10.1111/2041-210x.70194 -
Kaluza P, Kotzsch A, Gastner MT, Blasius B (2010) The complex network of global cargo ship movements. Journal of the Royal Society Interface 7(48): 1093-1103. https://doi.org/10.1098/rsif.2009.0495
» https://doi.org/10.1098/rsif.2009.0495 - Lagaaij R (1963) New additions to the bryozoan fauna of the Gulf of Mexico. Institute of Marine Science, Texas, Publication 9, 181-236.
- Leca L, D’Hondt JL (1993) Hippopodina tahitiensis n. sp., nouveau Bryozoaire Cheilostome (Hippopodinidae) de Polynésie Française. Cahiers de Biologie Marine 34: 401-409.
- Levinsen GMR (1909) Morphological and systematic studies on the cheilostomatous Bryozoa. Nationale Forfatterers Forlag, Copenhagen, 431 pp.
- Lopes RM (2009) Informe sobre as espécies exóticas invasoras marinhas no Brasil. Ministério do Meio Ambiente, Brasília, 440 pp.
- Marcus E (1937) Bryozoarios marinhos brasileiros I. Boletim da Faculdade de Philosophia, Sciencias e Letras, Universidade de São Paulo, Zoologia 1: 5-224.
- Marcus E (1939) Bryozoarios marinhos brasileiros III. Boletim da Faculdade de Filosofia, Ciências e Letras, Universidade de São Paulo, Zoologia 3: 113-299.
-
Marques AC, Klôh AS, Migotto AE, Cabral AC, Rigo APR, et al. (2013) Rapid assessment survey for exotic benthic species in the São Sebastião Channel, Brazil. Latin American Journal of Aquatic Research 41(2): 265-285. https://doi.org/10.3856/vol41-issue2-fulltext-6
» https://doi.org/10.3856/vol41-issue2-fulltext-6 - Migotto AE, Vieira LM, Winston JE (2011) Bryozoa. In: Amaral ACZ, Nallin SAH (Eds) Biodiversidade e ecossistemas bentônicos marinhos do litoral norte de São Paulo Sudeste do Brasil. UNICAMP/IB, Campinas, 265-272.
-
Miranda AA, Almeida ACS, Vieira LM (2018) Non-native marine bryozoans (Bryozoa: Gymnolaemata) in Brazilian waters: assessment, dispersal and impacts. Marine Pollution Bulletin 130: 184-191. https://doi.org/10.1016/j.marpolbul.2018.03.023
» https://doi.org/10.1016/j.marpolbul.2018.03.023 -
Nascimento KB, Migotto AE, Vaga CF, Vieira LM (2022) Occurrence of the bryozoan Amathia alternata Lamouroux, 1816 in the SW Atlantic: a new invasive species with potential impact on human livelihoods. Marine Biodiversity 52: 19. https://doi.org/10.1007/s12526-022-01263-7
» https://doi.org/10.1007/s12526-022-01263-7 -
Oricchio FT, Marques AC, Hajdu E, Pitombo FB, Azevedo F, et al. (2019) Exotic species dominate marinas between the two most populated regions in the southwestern Atlantic Ocean. Marine Pollution Bulletin 146: 884-892. https://doi.org/10.1016/j.marpolbul.2019.07.013
» https://doi.org/10.1016/j.marpolbul.2019.07.013 - Osburn RC (1940) Bryozoa of Porto Rico with a resume of West Indian bryozoan fauna. Scientific Survey of Porto Rico and the Virgin Islands 16: 321-486.
- Osburn RC (1952) Bryozoa of the Pacific coast of America, part 2, Cheilostomata-Ascophora. Report of the Allan Hancock Pacific Expeditions 14: 271-611.
-
Rocha RM, Vieira LM, Migotto AE, Amaral ACZ, Ventura CRR, et al. (2013) The need of more rigorous assessments of marine species introductions: a counter example from the Brazilian coast. Marine Pollution Bulletin 67(1-2): 241-243. https://doi.org/10.1016/j.marpolbul.2013.12.009
» https://doi.org/10.1016/j.marpolbul.2013.12.009 -
Ruiz GM, Carlton JT, Grosholz ED, Hines AH (1997) Global invasions of marine and estuarine habitats by non-indigenous species: Mechanisms, extent, and consequences. American Zoologist 37(6): 621-632. https://doi.org/10.1093/icb/37.6.621
» https://doi.org/10.1093/icb/37.6.621 -
Ruiz-Velasco S, Ros M, Guerra-García JM, López-Fé CM (2025) Fouling bryozoans in recreational marinas of the Canary Islands (North-Eastern Atlantic) with new records of non-indigenous and cryptogenic species. Zootaxa 5656(1): 1-63. https://doi.org/10.11646/zootaxa.5656.1.1
» https://doi.org/10.11646/zootaxa.5656.1.1 -
Souto J, Reverter Gil O (2024) Non-indigenous species of Bryozoa from anthropogenic habitats in the Bay of Cádiz (South Iberian Peninsula). Marine Biodiversity 54(76): 1-19. https://doi.org/10.1007/s12526-024-01466-0
» https://doi.org/10.1007/s12526-024-01466-0 -
Spalding MD, Fox HE, Allen GR, Davidson N, Ferdaña ZA, et al. (2007) Marine ecoregions of the world: A bioregionalization of coastal and shelf areas. BioScience 57(7): 573-583. https://doi.org/10.1641/B570707
» https://doi.org/10.1641/B570707 -
Teixeira LM, Creed JC (2020) A decade on: an updated assessment of the status of marine non-indigenous species in Brazil. Aquatic Invasions 15(1): 30-43. https://doi.org/10.3391/ai.2020.15.1.03
» https://doi.org/10.3391/ai.2020.15.1.03 - Tilbrook KJ (1999) Ecophenotypic variation in Hippopodina feegeensis (Busk, 1884) (Bryozoa: Cheilostomatida), with the description of a new species. Journal of Natural History 33(3): 447-463.
- Tilbrook KJ (2006) Cheilostomatous Bryozoa from the Solomon Islands. Santa Barbara Museum of Natural History Monographs 4(3): 1-385.
-
Tocci BRC, Vieira LM, Tamanaha MS, Resgalla Junior C (2022) Stranding events of drift organisms (Arribadas) in southern Brazil and the spread of invasive bryozoan in South America. Marine Pollution Bulletin 184: 114120. https://doi.org/10.1016/j.marpolbul.2022.114120
» https://doi.org/10.1016/j.marpolbul.2022.114120 -
Tyrrell MC, Byers JE (2007) Do artificial substrates favor nonindigenous fouling species over native species? Journal of Experimental Marine Biology and Ecology 342(1): 54-60. https://doi.org/10.1016/j.jembe.2006.10.014
» https://doi.org/10.1016/j.jembe.2006.10.014 -
Ulman A, Ferrario J, Occhipinti-Ambrogi A, Arvanitidis C, Bandi A, et al. (2017) A massive update of non-indigenous species records in Mediterranean marinas. PeerJ 5: e3954. https://doi.org/10.7717/peerj.3954
» https://doi.org/10.7717/peerj.3954 -
Vieira LM, Almeida ACS, Fehlauer-Ale KH, Migotto AE (2015) Filo Bryozoa: novas perspectivas no estudo da biodiversidade marinha no Brasil. Informativo Sociedade Brasileira de Zoologia (113): 4-6. https://sbzoologia.org.br/uploads/1477680802-bol113jun2015.pdf
» https://sbzoologia.org.br/uploads/1477680802-bol113jun2015.pdf -
Winston JE, Jackson JBC (2021) Coral reef-associated bryozoans of Jamaica. Zootaxa 4988(1): 1-281. https://doi.org/10.11646/zootaxa.4988.1.1
» https://doi.org/10.11646/zootaxa.4988.1.1 -
Xavier EA, Almeida ACS, Nogueira MM, Vieira LM (2023) Effects of substratum type and orientation on the recruitment of bryozoans in an artificial area of the Western Atlantic. Biofouling 39(7): 748-762. https://doi.org/10.1080/08927014.2023.2262928
» https://doi.org/10.1080/08927014.2023.2262928 -
Xavier EA, Almeida ACS, Vieira LM (2021) The role of artificial habitats on fouling bryozoan fauna in the southwestern Atlantic. Marine Pollution Bulletin 167: 112310. https://doi.org/10.1016/j.marpolbul.2021.112310
» https://doi.org/10.1016/j.marpolbul.2021.112310
