Lepidotrigla firmisquamis, Prokofiev & Yato, 2020

Prokofiev, Artem M. & Yato, Takuji, 2020, A new species of Lepidotrigla from the South China Sea off Vietnam (Teleostei: Scorpaeniformes: Triglidae), Zootaxa 4877 (2), pp. 373-385 : 374-380

publication ID	https://doi.org/ 10.11646/zootaxa.4877.2.9
publication LSID	lsid:zoobank.org:pub:A78EAA70-5E84-489A-B0DA-64618B7F7DEA
DOI	https://doi.org/10.5281/zenodo.4425118
persistent identifier	https://treatment.plazi.org/id/038687E2-FF9A-5F7B-FF41-FD55FC26FBCE
treatment provided by	Plazi
scientific name	Lepidotrigla firmisquamis
status	sp. nov.

Treatment

Lepidotrigla firmisquamis , sp. nov.

Figs. 2–5 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 , 6A View FIGURE 6

Holotype. MNHN 2019-0259 About MNHN , 114 mm SL, South China Sea, Vietnam, Nha Trang Bay , Cang Ca Vinh Luong, local by-catch by twin trawls, April–June 2009, collector A.M. Prokofiev.

Paratypes. Five specimens 95–125 mm SL, all from the South China Sea off Vietnam: BPBM 41378 About BPBM , 1 About BPBM (105), AMS I.49479-001, 1 (112), IORAS 03626 , 1 (125), all collected with holotype ; IORAS 03627 , 1 (95), Nha Trang, Cho Cua Be, local by-catch by bottom shrimp trawls above 100 m depth, 24 May – 19 June 2005, collector A.M. Prokofiev ; IORAS 03628 , 1 (114), Nha Trang, market, March–July 2007, collector A.M. Prokofiev.

Non-type specimen. IORAS 03629 , 1 (72), South China Sea , Vietnam, Co To Island, Bai Long Vi Archipelago, 4 June 2006, collectors D.A. Astakhov & A.M. Prokofiev. Although this specimen shows no obvious differences from the specimens of the type series, we do not include it in the paratype series because of its juvenile condition. Diagnosis. A species of Lepidotrigla with prominent blade-like projection of the rostral process, longer than wide, with series of denticles on inner side; nasal spine absent; postorbital groove deep, interrupted; parietal crests low lacking a spine; preopercular spine present, small; opercular spine short, not reaching to upper margin of the cleithral spine base; pectoral fin of moderate length, reaching to base of 4 th– 6 th anal-fin ray; first free pectoral-fin ray 68.3–80.0 % of length of pectoral fin, not reaching to tip of adpressed pelvic fin; scales strongly adherent; nape scaly, belly fully scaly; breast and interpelvic area naked; 54–58 lateral-line scales, 4 scale rows between dorsal-fin base and lateral line; 18–21 scale rows below lateral line ; VIII–IX (mainly IX) dorsal-fin spines; 14–15 (mainly 15) soft dorsal-fin rays; 14–15 (mainly 15) anal-fin rays; 22–24 (mainly 23) bucklers below dorsal-fin base, of which last 16–19 ending in strong sickle-like spine; inner side of joined pectoral fin with a blackish area lacking pale spots in preserved specimens; spinous dorsal fin lacking spot; vertebrae 11 + 19–21 = 30–32.

Description. Measurements and counts shown in Table 1 View TABLE 1 . Body robust anteriorly, slender posteriorly ( Fig. 2 View FIGURE 2 ). Head of moderate size, 37 [34–38]% of SL, with cranial roofing bones exposed, finely grained ( Fig. 3 View FIGURE 3 ). Snout 48 [38–48]% of head length, 1.9 [1.3–1.9 (mainly 1.7–1.9)] times in orbital diameter, with dorsal contour weakly concave; upper orbital margin raised; interorbital space deeply concave, 77 [77–83]% of orbital diameter. Mouth wide, extending to vertical through anterior border of orbit. Jaw teeth minute, in bands; vomer and palatines edentulous; premaxillary dentition completely exposed when mouth closed. Rostral projection ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 ) moderately long, flattened, 90 [67–93, usually 77 or more]% of orbital diameter, with stout and pungent outer spine bearing a series of small spinules along basal two-thirds of its inner margin; anteriormost 3 or 4 of these spinules more conspicuous, gradually decreasing in size posteriad, posteriormost spinules minute, commensurable in size with tubercles on head roofing bones. Rostral projections diverging at angle of 50–60º, snout margin between them notched; symphysis of lower jaw not visible from above. Head spines and ridges are shown on Fig. 3 View FIGURE 3 . Two preocular spines, well developed and separated, pointed (in holotype three equidimensional spines present on left side: Fig. 6A View FIGURE 6 ). Postocular spines forming a triangular process at postero-dorsal margin of orbit, often with some minute spinules on its posterior margin; postorbital groove deep behind postocular process, but not extending mesially past raised supraorbital margin ( Figs. 3A View FIGURE 3 , 6A View FIGURE 6 ). Sphenotic crest short but conspicuous, shelf-like, its outer margin often minutely serrated, ending as a small spine or rounded. Parietal crest poorly developed, very shallow anteriorly, only slightly raised posteriad, lacking a spine. Cheek with a weak longitudinal ridge originating below mid- or posterior third of orbit, extending to preopercular margin, and ending in a small spine. Opercular and posttemporal spines of similar length (including their ridges), sharp. Opercular spine straight or very slightly upturned, ending behind tip of posttemporal spine, well before upper base of cleithral spine. Cleithral spine the longest, pungent, reaching to below base of fifth dorsal-fin spine.

Base of dorsal fins with a paired row of 24 [22–24 (mainly 23)] bucklers (modified proximal pterygiophores), with eight bucklers below spinous dorsal-fin base, one buckler in interdorsal space, and the remaining bucklers below soft dorsal-fin base (terminal buckler below its last ray). Anteriormost 5 [4 to 7] bucklers multicuspid, remaining bucklers ending in single sharp and strong spine. First four dorsal-fin spines much thicker than the remaining ones; second to fourth spines longest, of similar length (equal or not more than 1 mm differ from each other); anterolateral margins of first three dorsal-fin spines [in paratype 114 mm SL (IORAS 03628) only basal half of third spine] finely serrate; remaining spines smooth. Tips of dorsal-fin spines pressed backward extending slightly behind origin of soft dorsal fin [but only reaching this origin in the largest paratype 125 mm SL (IORAS 03626)]. First dorsalfin pterygiophore inserting between neural spines of second and third vertebrae, next two interdigitating between third and fourth vertebrae, remaining pterygiophores interdigitating singly with the exception of 12 th and 13 th which interdigitate between 12 th and 13 th vertebrae [11 th and 12 th, 12 th and 13 th, or 13 th and 14 th]. First two anal-fin pterygiophores inserting between haemal spines of 12 th and 13 th vertebrae, third and fourth anal pterygiophores inserting between haemal spines of 13 th and 14 th vertebrae, and remaining interdigitating singly ( Fig. 2B View FIGURE 2 ) [in paratype IORAS 03628 first anal pterygiophore inserting anterior to haemal spine on 12 th vertebra, next two inserting between haemal spines of 12 th and 13 th vertebrae, and remaining interdigitating singly]. Pectoral fins extending to base of fifth [fourth to sixth] anal-fin ray, fifth and sixth joined rays longest. Free pectoral-fin rays much shorter than longest joined rays, gradually increasing in length from first to third. Uppermost (longest) free pectoral-fin ray reaching to anus [to anus or to anal-fin origin], not reaching distal tip of adpressed pelvic fin ( Fig. 5A View FIGURE 5 ). Pelvic fin reaches base of second anal-fin ray [second or third anal-fin ray in paratypes, except for one paratype (95 mm SL, IORAS 03627) reaching only to anal-fin origin]; third and fourth branched rays longest. Caudal fin emarginate, with lobes equal in length. First and second hypurals fused, third and fourth hypurals fused, fifth hypural free. Three epurals.

Flank scales ctenoid from the vertical through cleithral spine backward to the end of vertical fin, further backward above the lateral line; in other parts, cycloid. Both cycloid and ctenoid scales strongly adherent. Isthmus, chest, interpelvic area and area between the bases of pectoral and pelvic fins naked; belly scaly ( Fig. 5A View FIGURE 5 ). Predorsal area scaly except a narrow area in front of first dorsal-fin spine. Anterior flank scales deeper than long. Lateral line scales with branched pores, 4–5 branches on scales from anterior half of lateral line, decreasing backward to 3–4, then to 2 posteriad.

Overall coloration of preserved specimens pale, yellowish, exposed bones much darker, naked areas of skin pure white; orobranchial cavity unpigmented. Flanks above the level of cleithral spine with irregular dark pattern forming by agglomerations of melanophores. Spinous dorsal, anal and pelvic fins unpigmented [interradial membrane of spinous dorsal fin with very indistinct diffuse patches of dark pigment in some paratypes]; soft dorsal fin with dark melanophores forming a continuous but poorly expressed medial longitudinal band, caudal fin with more or less developed transverse grayish bar. Inner surface of pectoral fin with black membrane between second and ninth rays, skin of third to fifth, sixth (in distal half only) and ninth rays pale to pure white; no pale spots on whole surface ( Fig. 5B View FIGURE 5 ). Fresh coloration not documented.

Ontogenetic variations. The juvenile specimen, 72 mm SL (IORAS 03629), possesses denticles on the inner margin of the rostral process that are poorly developed, uniformly minute. It has the pelvic fins reaching to anal-fin origin only, like in the smallest paratype 95 mm SL (IORAS 03627) (vs. extending to second or third anal-fin ray in the larger specimens of the type series). Furthermore, this juvenile has a broader interorbital and interrostral width, longer and broader rostral projections, longer posttemporal spines, smaller cheek height, longer third free pectoralfin ray, greater first predorsal distance but shorter base of the spinous dorsal fin than the adult specimens of the type series ( Table 1 View TABLE 1 ). Other minor morphometric differences between the non-type juvenile and the specimens of the type series (in head length, orbital diameter and preanal length: Table 1 View TABLE 1 ) most probably reflect the individual rather than ontogenetic variations.

Etymology. The species epithet is created from the Latin words “firmus” (firm) and “squama” (scale) and reflects the characteristically strongly adherent squamation in this species.