Varicus roatanensis, Fuentes & Baldwin & Robertson & Lardizábal & Tornabene, 2023

Fuentes, Katlyn M., Baldwin, Carole C., Robertson, D. Ross, Lardizabal, Claudia C. & Tornabene, Luke, 2023, Two new species of Varicus from Caribbean deep reefs, with comments on the related genus Pinnichthys (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup), ZooKeys 1180, pp. 159-180 : 159

Varicus roatanensis sp. nov.

Fig. 6 Roatan goby, Gobio de Roatan (Spanish)

Type locality.

Roatan, Honduras; western Caribbean.

Holotype.

Honduras • 1 female 18.5 mm SL; western Caribbean, island of Roatan, west End, off Half Moon Bay, sta. IDABEL18-03; 16.304°N, 86.598°W; 237 m depth; 6 June 2018; Luke Tornabene, Rachel Manning, and Karl Stanley; 5% quinaldine-sulfate dispersed from Idabel submersible; UW 158127, DNA sample ROA18043.

Generic placement.

In addition to the molecular characters supporting the phylogenetic placement of this species, the following morphological characters support its inclusion in the genus Varicus : first dorsal spines VII; vertebrae 11+16; dorsal pterygiophore formula 3-221110; anal-fin rays I,9 or fewer (I,8 in V. roatanensis ); head pores absent; pelvic fins completely separate, lacking both anterior frenum and membrane connecting bases of innermost pelvic-fin rays; fifth pelvic-fin ray unbranched.

Diagnosis.

Varicus roatanensis is distinguishable from all other Varicus species by the following combination of characters: second dorsal fin I,8; anal fin I,8; pectoral fin 17; body scaled with 28 lateral rows of ctenoid scales, modified basicaudal scales present; pelvic rays 1-4 unbranched; body white with a series of elongate yellow dashes along lateral midline with scattered yellow spots between lateral midline and dorsal midline; dorsal and caudal fins white with bright yellow spots in life, pectoral, pelvic, and anal fins white.

Description.

General shape: body widest and deepest at the head, trunk tapering in width and depth posteriorly, dorsal head profile moderately sloping from dorsum to tip of snout.

Morphometrics (%SL): head length 30.3; eye diameter 10.8; snout length 5.9; upper-jaw length 10.3; post-orbital length 13.5; predorsal length 40.0; body depth at 1st dorsal-fin origin 15.1; body depth at anal-fin origin 12.4; preanal length 54.1; body depth at caudal peduncle 9.2; caudal-peduncle length 9.2; pectoral-fin length 20.5; pelvic-fin length 25.9.

Median and paired fins: first dorsal fin VII; second dorsal fin I,8; anal fin I,8; pectoral fin 17; pelvic fins I,5, fins well separated, lacking both anterior frenum and membrane connecting bases of innermost rays; 4th pelvic-fin ray longest, extending posteriorly to anus; rays 1-4 connected by a thin membrane, all unbranched without fleshy tips; 5th ray unbranched and approximately 25% the length of the 4th ray; caudal fin damaged, unable to determine fin-shape, branched caudal-fin rays13, segmented caudal-fin rays 17.

Vertebral skeleton: 27 vertebrae, 11 precaudal, and 16 caudal; dorsal pterygiophore formula 3-221110, unknown number of anal-fin pterygiophores inserted anterior to 1st haemal spine, as radiographs were unclear.

Head: jaw terminal, angled approximately 50 degrees from the horizontal axis of body, extending posteriorly to vertical anterior end of pupil; anterior naris on elongate tube, posterior naris barely visible as an opening on a slightly raised rim immediately anterior to eye; eyes large, dorsolateral, extending slightly above head profile; narrow interorbital space, operculum opening slightly larger than pectoral fin base; condition and presence/absence of teeth undeterminable due to condition of specimen.

Sensory papillae: skin of holotype is heavily abraded and no papillae are visible on the head or body.

Squamation: trunk covered with ctenoid scales, extending anteriorly to pectoral-fin base; 28 scales in lateral series, approximately 9 or 10 transverse scale rows; no scales on head; 2 modified basicaudal scales with enlarged ctenii present at dorsal and central margins at base of caudal-fin.

Genitalia: female with short, rounded papilla, wider at base and tapering to a slightly conical point; male unknown.

Color before preservation (Fig. 6 ): body translucent white with pale to bright yellow markings which are more visible when fish was photographed against white vs. black background. Head white with three slender bright yellow stripes below and posterior to eye, a slender yellow bar running down the center of the operculum; and with scattered melanophores, silver iridiophores, and bright yellow xanthrophores extending posterior from eye onto opercle; iris gold, heavily speckled with green-yellow dots; a thin silvery-white inner ring around pupil; three indistinct yellow bands across the nape, last one at level of origin of first dorsal fin. Body translucent white with three elongate yellow dashes along lateral midline, first dash under first dorsal fin, second dash below origin of second dorsal fin, third dash positioned below posterior half of second dorsal fin; nine small yellow spots extending ventrally from dorsal midline, first spot starting on nape, last spot above middle of caudal peduncle. First and second dorsal fins pale, each interradial membrane with one or two bright yellow spots, giving faint impression of one or two yellow stripes across fins. Caudal fin pale with a faint yellow curved bar across middle of rays, and a bright yellow vertical bar across base of caudal fin, with a triangular extension onto caudal peduncle. Anal fin pale, slightly translucent. Pectoral-fin base white with small horizontal patch of yellow on the dorsal part of fin base; pectoral rays white and semitransparent; pelvic fins pale.

Color in preservation (Fig. 6 ): body uniformly pale yellow with no visible pigmentation on head, trunk or fins.

Habitat.

Collected at 237 m. Specimen found on a silt-covered boulder with small 3-10 cm diameter caves and crevices.

Distribution.

Known only from the type locality off Roatan, Honduras.

Etymology.

The specific epithet Varicus roatanensis refers to the type locality, Roatan, Honduras.

Remarks

(Table 1 ). Varicus roatanensis can be distinguished from V. decorum , V. lacerta and V. prometheus and all species of Psilotris by the presence of multiple rows of scales on the side of the body (versus body scales absent; two modified basicaudal scales present in V. decorum , V. prometheus , and P. vantasselli ). The unbranched pelvic-fin rays in V. roatanensis distinguish it from V. adamsi , V. benthonis (Ginsburg, 1943), V. marilynae and V. vespa , all of which have rays 1-4 branched ( V. adamsi , V. marilynae and V. vespa also with fleshy pads at the tips of rays). Varicus roatanensis is most similar to V. bucca Robins & Böhlke, 1961, V. cephalocellatus Gilmore, Van Tassell & Baldwin, 2016, V. nigritus Gilmore, Van Tassell & Baldwin, 2016, and V. veliguttatus Van Tassell, Baldwin & Gilmore, 2016, in having scales on the body and unbranched pelvic-fin rays but differs from each of these species in body coloration. Varicus roatanensis is the only species in the genus to have elongate yellow dashes along the lateral midline, whereas V. veliguttatus , V. nigritus and V. decorum have distinct yellow or dark round blotches, saddles, or vertical bars on the body. While the fresh or living coloration of V. bucca is not known, and the type series may represent several species ( Tornabene et al. 2016b), the description and illustration of the preserved holotype clearly indicate a very dark anal fin that is heavily covered with melanophores ( Robins and Böhlke 1961). This pattern is shared with several other species of Varicus (e.g., V. adamsi , V. marilynae , V. nigritus , V. vespa ), but differs from that of V. roatanensis , which has a pale anal fin with a very faint yellow shading near the bases of the rays.

Figures

Figure 6. Varicus roatanensis sp. nov. holotype, UW 158127, 18.5 mm SL, female, prior to preservation (top two photos) and preserved (bottom). Photos by L. Tornabene.