Psilotris vantasselli, Tornabene & Baldwin, 2019

Tornabene, Luke & Baldwin, Carole C., 2019, Psilotris vantasselli, a new species of goby from the tropical western Atlantic (Teleostei: Gobiidae: Gobiosomatini: Nes subgroup), Zootaxa 4624 (2), pp. 191-204 : 193-197

Psilotris vantasselli sp. n.

urn:lsid:zoobank.org:act:7DC59A24-8AAA-4511-9430-3A0FA2EA489C

Clementine split-fin goby

Figs 1 , 2, 4–6

Type locality. Bonaire, southern Caribbean .

Holotype. USNM 442088 , male, 24.3 mm SL, tissue number BON17088 , Curasub submersible aboard R/ V Chapman, sta. CURASUB17-09, southern Caribbean , Bonaire, Belnem, south of Punt Vierkant , 12°05’42” N, 68°17’48” W, 149–159 m, Quinaldine , 22 February 2017, Lee Weigt , Barrett Brooks , Barbara van Bebber , Ian Silver-Gorges .

Paratypes: ANSP 191897, 2, 14.1 mm female and 15.0 mm SL (cleared and stained), sex undetermined, tissue numbers B941 and B942, Bahamas, Great Bahama Bank, New Providence Island, Green Cay, field number GC3, 16 m, rotenone, 15 November 2010, K.L. Ilves, M.W. Westneat, R.I. Eytan, G.W. Chaplin, R. Ilves, H. Herlter.

Generic placement. In addition to the molecular characters supporting the phylogenetic placement ( Figure 3 ), the following morphological characters support the inclusion of the new species in the Gobiosoma group of the tribe Gobiosomatini: first dorsal-fin spines VII; pterygiophore insertion pattern 3- 221110 (based on C&S paratype, not visible in radiograph of holotype); 27 vertebrate, 11 precaudal and 16 caudal; hypurals 1 and 2 fused to some extent with hypurals 3 and 4 and the terminal vertebral element; one epural. In addition to these characters, the following characters, which are present in most species of the Nes subgroup of the Gobiosoma group, support the inclusion of the new species in that subgroup: pelvic fins well separated, lacking both anterior frenum and well-developed membrane connecting innermost rays; cephalic lateralis canals and pores absent. Within the Nes subgroup, the following characters best support inclusion of the new species in Psilotris , although the distinctions between some genera in this group do not apply for all species within genera (see Comparisons and Discussion section below): pelvic-fin rays 1–4 branched without fleshy or flattened tips; fifth pelvic-fin ray unbranched; second dorsal-fin rays I,8–9 and anal-fin rays I,8; body coloration with bars or saddles on trunk and head; scales on side of the body absent except for pair of basicaudal scales; transverse papillae rows 5i /5s connected as a single continuous row.

Diagnosis: trunk with eight yellow bars, most bars with small bright-orange spot centered on lateral midline; pectoral rays 15–16; sensory papillae rows 5i and 5s connected as a single continuous row; one anal-fin pterygiophore inserted anterior to haemal spine (in cleared and stained paratype); body without scales except for two modified ctenoid basicaudal scales, one each at upper and lower bases of caudal-fin rays.

Description. General shape: body elongate and slender, uniform depth over most of the body; head slightly dorsoventrally depressed, with profile of head gradually sloping from eyes to tip of snout, snout short, shorter than eye diameter, anterior trunk cylindrical, becoming gradually more laterally compressed posteriorly. See Table 1 for morphometrics.

Head: jaw terminal and upturned, angled approximately 60 degrees from horizontal axis of body, extending posteriorly to vertical between anterior margin of eye and anterior margin of pupil; anterior nares elongate, narrow, transparent tubes without process from the rim; posterior nares inconspicuous, flush openings without raised rim near anterior margin of orbit, openings equal in size to anterior nares; no head canals or pores; eyes large, dorsolateral, extending slightly above head profile; bony interorbital space very narrow; operculum opening extending ventrally to just below ventral margin of pectoral-fin base; teeth in both jaws a single row of small, tightly packed, uniformly spaced canines with slightly recurved tips, becoming two rows anteriorly; tongue emarginate with slight indentation at tip. Fins: first dorsal fin VII, first three spines of equal length, with subsequent spines being sub-equal; second dorsal fin I,8–9 (8 in one paratype), last ray branched to base; pectoral-fin rays 15 in holotype, 16 in paratypes, all rays branched, longest fin ray extending posteriorly to vertical through space between first and second dorsal fins; pelvic fin I,5, fins completely separated, lacking both anterior frenum and membrane connecting bases of innermost rays; pelvic-fin rays 1–4 branched a single time, without fleshy tips or pads; 5th pelvic-fin ray small, ¼ the length of ray 4, unbranched, and tightly bound to ray 4; 4th pelvic-fin ray longest, extending posteriorly to anus (to base of anal-fin spine in one paratype); caudal fin with 17 segmented rays, 15 branched Selected osteological characters: pterygiophore insertion pattern 3- 221110 (based on C&S paratype, not visible in radiograph of holotype); 27 vertebrate, 11 precaudal and 16 caudal; hypurals 1 and 2 fused to some extent with hypurals 3 and 4 and the terminal vertebral element; one epural.

.

Squamation: head and body naked except for two small, partially embedded basicaudal scales, one each at the upper and lower bases of caudal fin, each with elongate cteni ( Figure 4 ).

Sensory papillae ( Figure 5 ): Pattern of neuromasts (sensory papillae) on head not well developed, with some possibly destroyed during collection. Side of head with 5 transverse rows of papillae; transverse rows 5s and 5i united as continuous row positioned anterior to row b, and stopping just above row d; longitudinal rows b and d short, consisting of only 5 and 4 neuromasts, respectively; paired interorbital neuromasts pb’ and pc’ present.

Coloration in live or fresh specimens ( Figs. 1 , 2; based on holotype): Ground color pale to translucent.

Head with three bright yellow bars radiating from eye, first bar oblique and extending over middle of upper and lower jaws, second bar vertical and extending beneath pupil, third bar vertical and extending from posterior margin of eye; two additional vertical yellow bars on head, one at posterior margin of preopercle and one behind posterior margin of opercle; a single yellow stripe on snout extending from anterior interorbital area onto tip of upper and lower jaws; yellow bars on head lightly outlined with melanophores (more apparent in recently dead versus live specimens); pupil black with blue iridescence, iris with patches of iridescent yellow and silver/white.

Trunk with eight yellow bars, each bar lightly outlined with melanophores; origins of eight bars as follows: beneath first dorsal spine, beneath sixth dorsal spine, immediately posterior to seventh dorsal spine, beneath third ray of second-dorsal fin, beneath seventh ray of second-dorsal fin, beneath last second-dorsal fin ray, over center of caudal peduncle, and at base of caudal fin; yellow bars beneath second-dorsal fin originate as V-shapes or saddles dorsally, ventral portions of bars less apparent in live versus freshly dead specimens; center of each yellow bar with bright-orange round or ovate spot centered on lateral midline (spots more apparent in live specimen); in life, a series of five bright, iridescent white, subcutaneous dashes present along upper portion of vertebral column; gas bladder bright white, visible through abdomen.

First dorsal fin lightly speckled with small white iridiophores and melanophores, with melanophores being concentrated more heavily on ventral portion of fin; ventral two-thirds of fin bright yellowish-orange, distal one-third white; Second dorsal and anal fins with pigment pattern similar to that of first dorsal fin, but anal fin with dark or dusky distal margin; pectoral fins with transparent interradial membranes, upper nine or ten rays with faint orange coloration, lower rays pale; pectoral-fin base with small, circular yellow blotches on upper and lower margins separated by wide oblique pale band with scattered melanophores; caudal fin yellow and white, yellow pigment forming two irregular, broad, bands each preceded anteriorly by narrow white band (banding pattern most prominent dorsally), distal margin of caudal fin white; pelvic fin unpigmented.

Coloration in preservation ( Figure 6 ): Ground color light tan. All yellow bars visible in life distinctly pale; spaces between pale bars heavily covered with melanophores, especially along margins of pale bars, and melanophores more pronounced on the anterior versus posterior part of body; base of pectoral fin with two pale blotches dorsally and ventrally, separated by wide oblique band of melanophores that extends onto bases of lower pectoralfin rays; dorsal and anal fins with scattered melanophores on interradial membranes; caudal fin with dark bar over bases of rays, followed by wide unpigmented bar; distal half of caudal fin uniformly covered with small scattered melanophores.

Distribution. Known from Bonaire and New Providence Island, Bahamas.

Etymology. The species epithet vantasselli is a patronym honoring James Van Tassell, whose work has contributed substantially to our understanding of the biology and systematics of the family Gobiidae , especially within the Gobiosomatini and other western Atlantic and eastern Pacific species. We propose the common name “Clementine split-fin goby,” as the small orange spots along the trunk are reminiscent of clementines (a small citrus fruit), and “split-fin goby” has been applied to several members of the Nes subgroup that have pelvic fins that are largely separated.

Figures

FIGURE 1. Live coloration of Psilotris vantasselli sp. n., USNM 442088, holotype, taken in an aquarium after capture. Photos by Barry B. Brown.

FIGURE 3. Bayesian inference molecular phylogeny based on combined mitochondrial and nuclear genes. Colors at nodes indicate posterior probability support values. Nodes with less than 0.50 support are shown as polytomies.

FIGURE 4. Modified basicaudal scales of preserved holotype temporarily stained with cyanine blue to show contrast (A, B, USNM 442088) and cleared and stained paratype (C, ANSP 191897) of Psilotris vantasselli, sp. n. Lower basicaudal scale in C is loosely attached and thus appears deflected anteriorly.

FIGURE 5. Sensory neuromast patterns of holotype of Psilotris vantasselli, sp. n., USNM 442088. AN—anterior naris, PNposterior naris.

FIGURE 6. Coloration of preserved holotype of Psilotris vantasselli, sp. n., USNM 442088. Photos by Luke Tornabene.