Verilus costai, Schwarzhans & Mincarone & Villarins, 2020

Schwarzhans, Werner W., Mincarone, Michael M. & Villarins, Bárbara T., 2020, A new species of the genus Verilus (Teleostei, Percomorpha, Acropomatidae) from Brazil, Zootaxa 4751 (3), pp. 589-596 : 590-595

Verilus costai sp. nov.

( Figures 1–4 , Table 1)

Holotype. NPM 6028, 76.2 mm SL, Brazil, State of Bahia, off Belmonte , REVIZEE, sta. E-511, 15°42’41”S 38°37’18”W to 15°44’14”S 38°39’12”W, 233–294 m, RV Thalassa , bottom trawl, coll. Paulo A. S. Costa et al., 12 June 2000, 18:03h.

Paratypes. MNRJ 51645 , 10 (57.1–75.9 mm SL), NPM 6027, 20 (59.9–85.4 mm SL), ZMUC P2396755-69 , 15 (50.3–79.6 mm SL), same data as for the holotype .

Additional non-type material. (n = 84) MNRJ 51646 , 42 (51.6–82.7 mm SL), NPM 3816, 42 (52.3–82.2 mm SL), same data as for the holotype .

Diagnosis. Moderately slender fishes with flat dorsal head profile leading up to ’humpback’ structure at beginning of first dorsal fin. Maximal SL not exceeding 86 mm. Snout pointed, inferior, steeply inclined. Pectoral fin rays 15–16, pectoral length 23.6–29.7% SL. Anal fin II+9. First anal-fin pterygiophore moderately long, with broad hollow base and straight to slightly backward bent tip. Vomer V-shaped with 2–3 rows of granular teeth and 0–1 longer tooth near sides of base. Palatine narrow, with 1–2 rows of granular teeth. Eye diameter 13.1–16.9% SL; snout length 8.2–11.3% SL. Gill rakers 27–31. Pseudobranchial filaments 15–23. Many longitudinal ridges on preopercular lobe. Inner edge of preopercle with 3–6 denticles. Otolith compressed (OL:OH = 1.3–1.35).

Description. Measurements and counts provided in Table 1. Counts: vertebrae 10 + 15 = 25; D1: IX; D2: I + 10; V: I + 5; P: 16; A: II + 9; developed gill rakers 27–31; pseudobranchial filaments 15–23. Measurements (in % of SL): body depth 27.3–33.3; head length 37.4–43.8; snout length 8.2–11.3; eye diameter 13.1–16.9; interorbital space 7.5–11.5; first predorsal length 31.0–46.7; second predorsal length 56.9–65.1; prepelvic length 36.4–43.7; pectoral fin length 20.9–29.7; preanal length 60.8–70.6; caudal peduncle length 15.5–21.9; caudal peduncle depth 8.6–13.9. Snout moderately long, sharply pointed, inferior, with steeply inclined mouth cleft; dorsal head profile almost flat, inclined up to beginning of first dorsal fin. Dorsal profile forming a distinct, obtuse angle resembling a ‘humpback’ feature at anterior edge of first dorsal fin ( Figure 1A ). Posterior edge of maxillary straight with posterodorsal and postero-ventral angles broadly rounded and postero-ventral angle slightly extended downward. Preopercular lobe with many radial longitudinal ridges; inner edge of preopercle with 3–6 denticles. Proximal-middle radial of first anal fin pterygiophore with broad hollow base and straight to slightly rearward bent tip, reaching to about half way of ribs of last abdominal vertebra ( Figure 2A ). First haemal spine with posterior expansion. All fin spine margins smooth. Less than 40 scales along lateral line system (visible only as scale pockets).

Dentition. Premaxillary with a pair of widely-placed, strong, fang-like canines near symphysis, followed posteriorly by a wide band of minute granular teeth. Dentary with a pair of narrowly-placed, strong fang-like canines, and a band of small conical teeth near symphysis, followed posteriorly by a row of small conical teeth and 2–3 enlarged fang-like canine teeth on each side. Vomer V-shaped, with 2–3 rows of granular teeth, and sometimes a single longer tooth near side of base. Palatine narrow with 1 row of granular teeth, sometimes 2 rows anteriorly; ectopterygoid without teeth.

Otolith morphology (n = 4; Figures 3 H–J). Otolith rather compressed, moderately thin, up to about 6 mm length. OL:OH = 1.3–1.35; OL:OT about 3.5–4.5. Dorsal rim high, nearly horizontal, with broadly rounded predorsal region and nearly orthogonal postdorsal angle at joint with posterior rim. Ventral rim deep, deepest distinctly in front of its middle, below rear end of ostium of sulcus. Rostrum well developed, sharply pointed, with convex lower margin and flat, nearly horizontal upper margin; excisura and antirostrum small. Rostrum c. 18% of OL. Posterior rim blunt, vertically cut, with angle at junction with ventral rim significantly below tip of cauda. Dorsal and posterior rims slightly undulating; ventral rim smooth. Inner face slightly convex with slightly supramedian positioned sulcus. Sulcus shallow, with very mildly flexed, long cauda reaching very close to posterior rim of otolith and wide, shallow, slightly upward inclined ostium. Ostium about twice as wide as cauda, with distinct colliculum. CaL:OsL = 1.15–1.25. Dorsal depression very wide. Ventral furrow distinct, running moderately distant and parallel to ventral rim of otolith. Outer face flat to slightly concave, smooth, with few short radial furrows near dorsal rim.

Coloration (in alcohol). Preserved fishes uniformly pale. Head bones semi-translucent and thus giving impression of darker color at interorbital. Rims of uppermost 1–2 rows of scale pockets along dorsal region of trunk with dark rims. Mouth pale; branchial cavity and peritoneum dark.

Size. Relatively small species reaching about 85 mm SL.

Geographic and bathymetric distribution. Known only from the type locality, off Belmonte, State of Bahia, Brazil, from 233 to 294 m depth ( Figure 4 ).

Etymology. Named after Dr. Paulo Alberto Silva da Costa (UNIRIO/ Brazil), in recognition of his contribution to the knowledge of deep-sea fishes from Brazil.

Comparison. Verilus costai appears allopatric to V. pseudomicrolepis ( Figures 1B , 2B , 3 A–G). It differs from V. pseudomicrolepis in the higher number of gill rakers (27–31 vs. 21–25), the lower number of pseudobranchial filaments (15–23 vs. 21–28), the shorter snout length (8.2–11.3 vs. 11.3–13.4% of SL), the generally shorter pectoral fin (20.9–29.7 vs. 27.3–31.6% of SL) although this characteristic has to be used carefully due to the often poorly and incompletely preserved pectoral fin and due to some overlap, the slightly bent tip of the first anal pterygiophore (vs. straight), and the more compressed otoliths (OL:OH = 1.3–1.35 vs. 1.35–1.5), indicated in x-rays by the shorter otic capsule in V. costai in comparison to V. pseudomicrolepis ( Figure 2 ). Verilus costai is a relatively small species and does not reach the size of V. pseudomicrolepis (maximum recorded 85 mm vs. 145 mm [ Mejía et al. 2001]). Specimens of similar sizes ( V. pseudomicrolepis of 66.6–99.0 mm SL [ Table 1] and large specimens of V. costai ) were compared to eliminate potential ontogenetic effects that are known to occur in the number of gill rakers and the pseudobranchial filaments ( Schwarzhans & Prokofiev 2017). In the otoliths, it was found that small specimens of V. pseudomicrolepis of 4–6 mm of OL ( Figures 3 B–D) showed a distinct marginal crenulation, a typical feature found in otoliths of subadult fishes below the threshold of morphological maturity, while this was not the case in otoliths of V. costai of comparable sizes.

Comparative material examined. Verilus pseudomicrolepis . CAS 61038, 1 (87 mm SL), trawled by RV Oregon II, sta. 46095, off Puerto Rico, 18°13’18”N, 67°19’30”W, 366 m , T. Iwamoto , 21 August 1987 . CAS 61164, 1 (91 mm SL), trawled by RV Oregon II, sta. 46036, off U.S. Virgin Islands, 17°38’42”N, 64°56’48”W, 475–512 m , T. Iwamoto , 10 August 1987 . CAS 61183, 1 (138 mm SL), trawled by RV Oregon II, sta. 45998, off Puerto Rico, 18°10’N, 67°25’W, 91 m , T. Iwamoto , 5 August 1987 . USNM 229541 , 13 (71–99 mm SL), trawled by RV Oregon II, cruise 22, sta. 11219, off Honduras, 16°39’N, 82°45’W, 320 m, 25 October 1970 . USNM 407012 , 1 (66.6 mm SL), trawled by RV Miguel Oliver , sta. MOC11-01, off Panama, 08°58’12’’N, 77°27’26’’W, 252–289 m, D. Robertson and C. Castillo, 6 January 2011 . USNM 407758 , 1 (115 mm SL), trawled by RV Miguel Oliver , sta. MOC11- 89, off Belize, 16°46’15.6”N 87°55’47.6”W, 393–400 m, D. Robertson and C. Castillo, 29 January 2011 . USNM 436691 , 1 (88 mm SL), trawled by RV Oregon II, cruise 4, sta. 10195, off Nicaragua, 14°16’48”N 81°55’12”W, 329 m, 19 November 1968 .

Figures

FIGURE 1. A. Verilus costai sp. nov., holotype, NPM 6028, 76.2 mm SL, Brazil, off Belmonte, State of Bahia, 15°42’41”S 38°37’18”W to 15°44’14”S 38°39’12”W, 233–294 m, RV Thalassa, bottom trawl, 12 June 2000. B. Verilus pseudomicrolepis (Schultz, 1940), USNM 436691, 88.0 mm SL, off Nicaragua, 14°16’48”N 81°55’12”W, 329 m, RV Oregon II, shrimp trawl, 19 November 1968. Scale bar = 10 mm.

FIGURE 2. A. Verilus costai sp. nov., holotype, NPM 6028, 76.2 mm SL. B. Verilus pseudomicrolepis (Schultz, 1940), USNM 436691, 88.0 mm SL. Scale bar = 10 mm.

FIGURE 3. Otolith morphology. A–G. Verilus pseudomicrolepis (Schultz, 1940): A. CAS 61183, 138 mm SL; B–C. CAS 61164, 91 mm SL (C ventral view); D. CAS 61038, 87 mm SL; E–F. USNM 407758, 115 mm SL (F ventral view); G. USNM 407012, 66.6 mm SL. H–J. Verilus costai sp. nov., paratypes: H–I. ZMUC P2396755, 78 mm SL (I ventral view); J. ZMUC P2396756, 74 mm SL. K–M. Verilus mutinensis (Bassoli, 1906), coll. W. Schwarzhans: K–L, Licata, Sicily, early Pliocene Zanclean (L ventral view); M. east of Agrigento, Sicily, early Pliocene Zanclean (reproduced from Schwarzhans 1978, as Neoscombrops praeannectens Weiler, 1971).

FIGURE 4. Distribution of Verilus costai sp. nov. (triangle) and Verilus pseudomicrolepis (circles; based on specimens deposited at CAS, MCZ, USNM and UF fish collections). The black circle represents the type locality of Verilus pseudomicrolepis. Crosses represent localities of the fossil Verilus mutinensis, Late Miocene to Early Pleistocene (after Schwarzhans, 1978, 1986; Girone et al., 2006; Agiadi et al., 2013, 2018). Each symbol may represent several specimens and/or stations.