Description of a second genus of Chespiritoinae (Coleoptera, Lampyridae), with updates on the subfamily diagnosis and key to species and genera

ABSTRACT

Xacoxoxotlani chiapensis Ferreira new genus and new species, the second genus of the lampyrid subfamily Chespiritoinae is described from Chiapas, Mexico. The new taxon is diagnosed, illustrated and compared with Chespirito Ferreira, Keller and Branham, 2020. An updated diagnosis of the subfamily Chespiritoinae is provided along with a new identification key and distribution map for the genera and species within this subfamily.

Keywords:  Dark-firefly; Bioluminescence; Neoteny; Paedomorphosis; Elateroidea

Introduction

The Chespiritoinae is a subfamily of non-bioluminescent fireflies which were recently described from the Nearctic and Neotropical regions (sensuFerreira et al., 2020; Morrone et al., 2022). The subfamily is currently comprised by the genus Chespirito Ferreira, Keller & Branham, 2020, and six species (Fig. 1), five of which are distributed in Mexico, and one in the United States (Ferreira et al., 2020, 2022). Very little about Chespiritoinae is known. Members of this subfamily display a diversified and wide habitat preference, ranging from desert environments and relatively low elevations to cloud forests with high altitudes (Ferreira et al., 2020, 2022). The morphology of Chespirito and the lack of females in collections conforms with observations of other beetle groups known or suspected to be affected by the paedomorphosis syndrome (Ferreira and Ivie, 2022; Ferreira et al., 2022).

Figure 1
Diversity of Chespirito species. A. Chespirito ballantynae. B. Chespirito costae. C. Chespirito hintoni. D. Chespirito lloydi. E. Chespirito milleri. F. Chespirito zaragozai.

During a survey of the soft-bodied beetles of the Florida State Collection of Arthropods, Gainesville, Florida, United States (FSCA), a specimen initially identified as a Chespirito species, from Chiapas, Mexico, was found among the unidentified Lycidae material of that collection. A closer examination revealed that the specimen represented a new genus and species near Chespirito. I take this opportunity to describe this individual, to update the diagnosis of the subfamily Chespiritoinae, the identification key, and distribution map for the species in this group.

Material and methods

The single studied specimen is deposited at the FSCA (curator: Paul Skelley). The identification and placement of the specimen in Chespiritoinae was based on previous literature on the group (Ferreira et al., 2020, 2022). The specimen was studied under a Leica® S9E, with magnification up to 50×. The genitalia was dissected after the whole specimen was relaxed in hot H₂O; the dissected genitalia is permanently preserved in glycerin in a microtube mounted on the pin under the specimen. Morphological terminology follows Lawrence et al. (2011) and the description style of Ferreira et al. (2020, 2022). Photos of specimens were taken with a Canon 6D DSLR with a MP-E 65 mm lens and a Leica M205C attached to a Leica camera DFC450. Images were stacked using Zerene Stacker® version 1.04. Enhancements to digital images were made in Adobe Photoshop® CC 2024 and Adobe Photoshop® CC for iPad, and plate preparations were made in Adobe Illustrator® CC 2024. The distribution map was generated using the software Google Earth and Quantum GIS 3.16, using the maps available on the website http://www.naturalearthdata.com, a free public database of maps.

Results

Taxonomy

Lampyridae Rafinesque, 1815

Chespiritoinae Ferreira, Keller & Branham, 2020

Subfamily composition. Chespirito Ferreira, Keller & Branham, 2020 and Xacoxoxotlani Ferreira new genus.

Distribution. Mexico and Southwestern United States (Fig. 5).

Figure 5
Distribution map of Chespiritoinae genera and species.

Updated diagnosis. Chespiritoinae and its two genera can be readily identified from all other Lampyridae by the combination of the following characters: the presence of a setose, filiform or subserrate antennae, with antennomeres 2 and 3 subequal in size and length, both much smaller than all other antennomeres; the pronotum medially constricted, ranging from distinctly to weakly constricted (Figs. 1, 2B); the area adjacent to disc strongly punctate, with an alveolate appearance, medially bearing a distinctly developed carina; the prosternum transverse or longer than wide (Fig. 3A), divided medially by a distinct suture, with the posterior margin forming a narrow, but visible, process; the mesocoxae distinctly separated (Fig. 3A); the elytra smooth, weakly punctuated, dehiscent, bearing two costae on each elytron (Figs. 1, 2A); the male genitalia trilobate, bulb-shaped (Fig. 4A–B).

Figure 2
Xacoxoxotlani chiapensisnew genus and species. A. Dorsal habitus. B. Pronotum detail. Scale bars: 1 mm.

Figure 3
Xacoxoxotlani chiapensisnew genus and species. A. Ventral view. B. Head and frons detail. C. Lateral view. D. Ventral view of last four abdominal ventrites (5–8). E. Dorsal view of last three abdominal tergites (VI–VIII). Scale bars: 1 mm.

Figure 4
Male genitalia and aedeagal sheath of Xacoxoxotlani chiapensis new genus and species. Male genitalia, distal tip oriented upwards. A. Dorsal view. B. Ventral view. Aedeagal sheath detail, distal tip oriented upwards. C. Lateral view. D. Ventral view. Scale bars: 200 $\mu$m.

Xacoxoxotlani Ferreira new genus

urn:lsid:zoobank.org:act:2E73260F-5144-41B8-82C3-2D2AE829EA0A

Figs. 2-5.

Type species.Xacoxoxotlani chiapensisnew species.

Etymology.Xacoxoxotlani, from the Nahuatl, one of the languages spoken by the indigenous people of Central Mexico: Xaco, meaning dark, and xoxotlani, meaning firefly (Wood, 2024), in allusion to the fact that this is a non-bioluminescent (a “dark”) firefly.

Diagnosis. With the subfamily diagnosis (see above). Pronotum triangular, isosceliform (Fig. 2B) (vs. subquadrate or square in Chespirito); the protibiae 1/3 shorter than profemora (Fig. 3A) (vs. pro- tibiae and femora subequal in length in Chespirito); antennomeres 3–11 subserrate, dorsoventrally flattened, antennomere 11 distally notched (Fig. 2A) (vs. filiform, round in cross section in Chespirito).

Species Included.Xacoxoxotlani chiapensisnew species.

Description. General body coloration dark brown (Figs. 2A, 3), pronotal disc, prosternum, and tarsi yellow (Figs. 2A–B, 3A–C). Body setose, dorsal, thoracic and abdominal pubescence short and erect, sparsely distributed (Fig. 1), remainder of body with fine light brown pubescence throughout (Figs. 2–3).

Body. Head: Longer than wide (Fig. 3B), dorsal texture alveolate (Fig. 3B), posteriorly or completely covered by pronotum, prognathous, frons convex and slightly protruding (Figs. 2A–B). Eyes hemispherical, projecting anterolaterally, coarsely granulate (Figs. 2, 3A–B). Mouthparts: Maxillary palp four-segmented, setose; palpomeres I small, short, ca. ¼ the length of palpomeres II; palpomeres II small, half the length of III; palpomeres III and IV subequal in length, the IV apically truncate and discolored (Fig. 3B). Labial palp apparently three-segmented. Mandibles developed, falciform, small (Fig. 3B). Posterior margin of epistoma emarginate, round (Fig. 3B); labrum indistinct from clypeus, membranous and setose, transverse (Fig. 3B). Antennae: 11-segmented; antennifers separated by a third of antennifer width; in resting upfront position, as long as two-thirds of elytra, densely setose; scape subconic, pedicel ⅓ shorter than precedent, flagellomere 3 subequal in length with the precedent; antennomeres 4–11 subserrate, connected by thin translucent membranes, dorsoventrally flattened; antennomere 11 distally notched (Figs. 2A–B, 3A–C)

Thorax. Prothorax: Pronotum isosceliform (Fig. 2A–B); bordering margins thick; anterior angle slightly bisinuated (Figs. 2A–B); longitudinal carina absent (Fig. 2A); disc alveolate, bearing irregularly shaped cells, relatively larger when compared to cells in adjacent area (Fig. 2B); adjacent area strongly punctate, with small irregular cells smaller than those closer to center (Fig. 2B). Hypomeron concave, closed in front, the inner margin attaining the anterior angle, when viewed laterally, alveolate (Fig. 3C). Prosternum elongate, medially constricted, divided in the middle by a distinct longitudinal suture forming two plates; anteriorly with a narrow inter-coxal process (Figs. 3A). Mesothorax: Mesospiracles tubular, somewhat stout, resting right above mesanepisternum. Mesoventrite subtrapezoidal, medially bearing a distinct keel, posteriorly reaching anterior margin of metaventrite, laterally connected to mesanepisternum; mesepimeron anteriorly touching posterior portion of metanepisternum. Scutellar shield rectangular, slightly notched apically. Metathorax: Metaventrite alveolate, convex, posterolateral angles round (Fig. 3A); metadiscrimen complete, metanepisternum and metepimeron elongate, widest in the apex (Fig. 3A). Elytra: dehiscent, 4.5× longer than pronotum, covered with small papillae, each bearing single tiny seta; with two weakly developed costae, secondary costae absent (Fig. 2A). Legs: slender, elongate (Fig. 2); protrochantin exposed; trochanters pill-shaped; protibiae 1/3 shorter than profemora (Fig. 3A); meso- and meta- femora and tibiae subequal in length femora sturdy, slightly fusiform; tibiae slightly clavate, slender; pro- and mesocoxae conical, obliquely positioned, procoxae contiguous, mesocoxae separated, metacoxae transverse; tarsal formula 5-5-5, all tarsomeres narrow; tarsomere I very long, as long as sum of tarsomeres II–IV (Fig. 3C), bearing simple claws.

Abdomen with eight ventrites, lantern absent; ventrite 7 trilobed, median lobed round, lateral lobes apically acuminate, pronounced (Fig. 3D, in green); ventrite 8 obovate, apically entire, not notched (Fig. 3D, in red); tergite VIII apically medially notched apically (Fig. 3E). Aedeagal sheath: inserted in the abdomen apex, not externally visible, composed of a dorsal (green) and a ventral plate (red); dorsal plate oval, scoop shaped, tapering toward base (Fig. 4C-4D); ventral plate subdivided in two: a basal, bisinuate (Fig. 4C–4D), and a fusiform, elongate plate, basally fused to basal plate. Male genitalia trilobate, symmetrical (Figs. 4A–B); median lobe sword shaped, apically acuminate; parameres apically round (Figs. 4A–B) shorter than median lobe; phallobase transverse.

Females. Unknown and presumably affected by the paedomorphosis syndrome (see introduction section).

Length (exposed portion of head+pronotum+elytra). 6.2 mm. Width (across humeri). 1.2 mm.

Distribution. Xacoxoxotlani is only known to occur in Chiapas, Mexico (Fig. 5).

Biology and immatures. Like in Chespirito, immature stages and information about the ecology and biology of Xacoxoxotlani is unknown.

Xacoxoxotlani chiapensis new species

urn:lsid:zoobank.org:act:8656EFA8-85A7-4474-9FCB-3C82D302AC05

Type material (1). Holotype. 1 male: Mexico: Chiapas; Jitotol de Zaragoza; 30 June 1991; JCBurne & DB Thomas (FSCA).

Etymology. In allusion to the locality of the holotype, in Chiapas.

Description and diagnosis. The diagnosis and description of Xacoxoxotlani chiapensis is coextensive with the generic description and diagnosis.

Distribution. Jitotol de Zaragoza, Chiapas, Mexico, in the Mexican transition zone at Chiapas Highlands province (sensuMorrone et al., 2022) (Fig. 5).

An updated key to the male genera and species of Chespiritoinae (modified from Ferreira et al., 2022 )

1. Antennomeres IV–XI subserrate, dorsoventrally flattened, terminal antennomere distally notched (Fig. 2A); pronotum triangular shaped (Fig. 2B) .............................................................................. Xacoxoxotlani chiapensis new genus and species

1’. Antennomeres IV–XI filiform, round when viewed in cross-section; pronotum rectangular, anterior margins round, posterior margins slightly bisinuate... Chespirito Ferreira, Keller & Branham (Fig. 1) ................................................................................ 2

2. Pronotum with disc yellow, median longitudinal carina absent... Chespirito ballantyneae Ferreira, Keller & Branham, 2020 (Fig. 1A)

2’. Pronotum completely dark brown, strong median longitudinal carina present...................................................... 3

3. Ventrite 8 entire, apically acuminate or round........................................................... 4

3’. Ventrite 8 apically notched and bifurcated................................................................... 6

4. Apical three abdominal ventrites dark brown... Chespirito lloydi Ferreira, Keller & Branham, 2020 (Fig. 1D)

4’. Apical three abdominal ventrites yellow................................................................. 5

5. Apex of last visible tergite distinctly notched medially... Chespirito milleri Ferreira, Keller & Ivie, 2022 (Fig. 1E)

5’. Apex of last visible tergite round... Chespirito costae Ferreira, Keller & Ivie, 2022 (Fig. 1B)

6. Pronotum strongly constricted medially; elytra strongly dehiscent; antennae moderately long, surpassing elytral basal third when extended posteriorly.......................................................... Chespirito zaragozai Ferreira, Keller & Branham, 2020 (Fig. 1F)

6’. Pronotum weakly constricted medially (Fig. 1A); elytra not dehiscent (Fig. 1A); antennae short and stubby, barely surpassing humeral region when extending posteriorly............................................ Chespirito hintoni Ferreira, Keller & Ivie, 2022 (Fig. 1C)

Acknowledgments

I am grateful to Paul Skelley (FSCA) for loaning the material that resulted in the discovery of this taxon; to Stephanie Wood (University of Oregon) and Dulce Horn (Mayan Language Initiave) for their suggestions and assistance with the Mesoamerican names used for the etymology section of this manuscript; to the two anonymous reviewers who provided important feedback in an earlier version of this manuscript; and to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) of Brazil for the novation process 202559/2015-7.

• urn:lsid:zoobank.org:pub:81B2C15F-847E-499A-92BE-3B6405B3B62D

References

• Ferreira, V. S., Keller, O., Branham, M. A., 2020. Multilocus phylogeny support the non-bioluminescent firefly Chespirito as a new subfamily in the Lampyridae (Coleoptera: elateroidea). Insect Syst. Divers. 4 (6), 1-13. https://doi.org/10.1093/isd/ixaa014
  » https://doi.org/10.1093/isd/ixaa014
• Ferreira, V.S., Ivie, M.A., 2022. Lessons from a Museum’s Cabinet: DNA barcoding and collections-based life stage associations reveals a hidden diversity in the Puerto Rican bank Paedomorphic Lycidae (Coleoptera, Elateroidea). Insect Syst. Divers. 6 (3), 1–36. https://doi.org/10.1093/isd/ixac006
  » https://doi.org/10.1093/isd/ixac006
• Ferreira, V. S., Keller, O., Ivie, M. A., 2022. Descriptions of new species of Chespirito Ferreira, Keller & Branham (Coleoptera: Lampyridae: Chespiritoinae) and the first record for the subfamily in the United States. Zootaxa 5124 (2), 230-237. https://doi.org/10.11646/zootaxa.5124.2.8
  » https://doi.org/10.11646/zootaxa.5124.2.8
• Lawrence, J. F., Ślipiński, A., Seago, A. E., Thayer, M. K., Newton, A. F., Marvaldi, A. E., 2011. Phylogeny of the Coleoptera based on morphological characters of adults and larvae. Ann. Zool. 61, 1-217. https://doi.org/10.3161/000345411X576725
  » https://doi.org/10.3161/000345411X576725
• Morrone, J. J., Escalante, T., Rodríguez-Tapia, G., Carmona, A., Arana, M., Mercado-Gómez, J. D., 2022. Biogeographic regionalization of the Neotropical region: new map and shapefile. An. Acad. Bras. Cienc. 94, e20211167.
• Wood, S., 2024. Online Nahuatl Dictionary, Stephanie Wood, ed. (Eugene, Ore.: Wired Humanities Projects, College of Education, University of Oregon, ©2000–present). Available in: https://nahuatl.wired-humanities.org/ (accessed 18 June 2024).
  » https://nahuatl.wired-humanities.org/

Edited by

• Associate Editor:
  Marcela Monné

Publication Dates

• Publication in this collection
  18 Oct 2024
• Date of issue
  2024

History

• Received
  18 June 2024
• Accepted
  27 Aug 2024