Parascombrops yamanouei Schwarzhans, Prokofiev & Ho

Schwarzhans, Werner W. & Prokofiev, Artem M., 2017, Reappraisal of Synagrops Günther, 1887 with rehabilitation and revision of Parascombrops Alcock, 1889 including description of seven new species and two new genera (Perciformes: Acropomatidae), Zootaxa 4260 (1), pp. 1-74 : 54-56

Parascombrops yamanouei Schwarzhans, Prokofiev & Ho , new species

Figs. 7M , 10F , 13M , 15 S – U, 30, 35, Tables 2–7

Material examined (28 specimens). Holotype NMMB-P13850, 99 mm SL, Dong-gang , Pingtung, southwestern Taiwan, ca. 100 m, midwater trawl, 10. Aug. 2011, coll. H.- C. Ho . Paratypes: AMS I.21625-010, 70.5 mm SL, 10°98’S, 130°28’E; NMMB-P11343, 9 specimens, 65–82 mm SL, Dong-gang , Pingtung, southwestern Taiwan, 0 4. Sep. 2010 ; NMMB-P13672, 93 mm SL, Dong-gang , Pingtung, southwestern Taiwan, 0 2 Jul. 2011 ; NMMB- P14237, 8 specimens, 80–109 mm SL, Dong-gang , Pingtung, southwestern Taiwan, 0 6 Sep. 2013 ; NMMB- P 15571, 102 mm SL, Dong-gang, Pingtung, southwestern Taiwan ; NMMB-P23097, 7 specimens, 64–71 mm SL, Dong-gang, Pingtung, southwestern Taiwan.

Diagnosis. Deep-bodied species with strongly convex dorsal head profile and pointed snout. Anal fin II + 7. Pectoral fin with 14–15 rays, pectoral length 23.5–26.5% SL. Gill rakers 14–16. Pseudobranchial filaments 18–23. First anal-fin pterygiophore moderately long, straight, with broad, hollow tip. Vomer triangular with V-shaped tooth patch, anteriorly with reduced dentition, one large tooth on either side posteriorly. Palatines narrow, with 1–2 rows of granular teeth. Ectopterygoid short, wide, with 3–6 rows of granular teeth. Orbital diameter 11.0–12.8% SL. Small spike on preopercular lobe or smooth. Otolith compact (OL:OH = 1.55–1.65), with intensely crenulated rims, particularly posteriorly.

Description. Counts and measurements (see also summary Tables 2–7). Counts: D1: IX; D2: I + 9; A: II + 7; V: I + 5; P: 15 (14–15); developed gill rakers 15 (14–16); pseudobranchial filaments 20 (18–23). Morphometrics (% of SL): orbit 12.5 (11.0–12.8); snout 9.2 (8.7–10.1); head length 37.6 (34.4–39.3); pectoral length 25.6 (23.5–26.6); maximal body depth 32.6 (29.6–33.6); predorsal length 40.4 (37.9–42.2); preventral length 37.2 (36.0–39.1); preanal length 68.9 (64.9–73.4). Snout pointed; interorbital space strongly convex. Posterior edge of maxilla straight with postero-dorsal and postero-ventral angles rounded and postero-ventral angle not extended; posterior rim of the maxilla vertical. Hind margin of lower part of subopercle and of interopercle weakly serrated or smooth. Preopercular lobe without longitudinal ridges, but two-thirds of specimens examined with small spike; denticles of hind margin serration extending somewhat into crests onto preopercular lobe; inner edge of preopercle with 3–5 small denticles not extending along ventral branch. Proximal-middle radial of first anal-fin pterygiophore moderately long, straight, with a broad, hollow tip, reaching ribs of tenth abdominal vertebra. First haemal spine with narrow posterior expansion. Pelvic-fin spine serrated along its outer edge; all other fin spines smooth.

Dentition. Premaxilla with a pair of canines near symphysis, followed posteriorly by a wide band of minute granular teeth. Dentary with a pair of canines, followed by a band of minute conical to granular teeth, and a row of 3 conical to caniniform teeth on sides. Vomer with V-shaped tooth patch with reduced dentition expressed in very few granular teeth anteriorly and one long conical teeth at rear on either side. Palatines narrow, anteriorly with 1 or 2 longer teeth and thereafter with 1 or 2 rows of granular teeth; ectopterygoids wide, with 3 to 6 rows of granular teeth. Tongue without teeth.

Otolith morphology (n = 3). Otolith compressed, moderately thick, up to about 6 mm length. OL:OH = 1.55–1.65; OL:OT about 3–3.5. Dorsal rim with broadly rounded medio-dorsal region and rounded postdorsal angle close to posterior rim. Ventral rim deepest slightly in front of its middle, below collum of sulcus. Rostrum well developed, moderately sharply pointed; distinct and sharp excisura and antirostrum. Posterior rim broadly rounded. All rims crenulated posterior half otolith more intensely than anterior part. Inner face markedly convex with slightly supramedian positioned sulcus. Sulcus shallow, with long cauda and moderately wide, shallow ostium. Ostium about twice as wide as cauda, with distinct colliculum. Cauda with rounded, slightly bent tip, terminating close to posterior tip of otolith. CaL:OsL = 1.10–1.15. Dorsal depression wide, with indistinct dorsal margin. Ventral furrow indistinct, moderately close to ventral rim of otolith anteriorly and slightly bending away from it backwards towards tip of cauda. Outer face slightly concave, but with thickened umbo in post-central position; with many fine radial furrows near rims.

Coloration (in alcohol). Preserved fishes uniform pale coloration. Dorsal surface of head from tip of snout, tip of lower jaw and scale pockets above lateral line with numerous diffuse small dotted melanophores, on body concentrated along rear half of scale pockets. Dorsal and anal fins dusty gray with numerous minute diffuse melanophores, caudal fin likewise dusty gray, with dark rim and pectoral and pelvic fins translucent, pale. Mouth pale; branchial cavity dark, black in part; peritoneum pale.

Size. Fishes up to slightly over 100 mm SL.

Discussion. Parascombrops yamanouei is a deep bodied species like P. analis , P. madagascariensis and P. serratospinosus (maximal body depths 28–33.9% SL; mean 30–31.5% SL). Of these, P. analis is readily distinguished by the presence of three anal spines (vs two) and P. serratopinosus by the presence of serrated spines in the dorsal and anal fins. Parascombrops madagascariensis is the one with the closest resemblance. Parascombrops yamanouei differs from P. madagascariensis in the triangular vomer bearing a V-shaped tooth patch with anteriorly reduced, very small granular teeth (vs vomer and tooth patch both triangular with 2–3 rows of granular teeth anteriorly and a row of long teeth along the rear edge), the wide ectopterygoid (3–6 rows of granular teeth vs 1–2 rows), the straight and rather short first anal-fin pterygiophore (vs slightly bent toward tip and long), and the usual presence of a spike on the preopercle (vs always smooth). Smaller specimens in the range of 65–75 mm of SL sometimes have 1 row of granular teeth on the vomer and 3 to 4 rows of granular teeth on the ectopterygoid. The intensely crenulated and rather thick otolith is unique within all species of the genus with otoliths studied.

Geographic and bathymetric distribution. Parascombrops yamanouei appears to be restricted to an antitropical distribution. It is common off Taiwan, and known from a single specimen from the Timor Sea, off NW Australia. It seems to differ from other species in the genus being caught at moderate depth (about 80–100 m) in open water rather than demersal.

Ecology. During the fishing season for the Sakura shrimp Lucensosergia lucens (Hansen, 1922) (December to May) in Dong-gang, southwestern Taiwan, this species was collected by midwater trawling with other midwater fishes (i.e. Squaliolus aliae Teng, 1959 , Etmopetrus splendidus Yano, 1988 , Bregmaceros spp. and nyctoepipelagic mytophids). This strongly indicates that this species is pelagic or semi-pelagic. Specimens were usually collected together indicating that it may also form midwater-schools. Off Dong-gang this species is often collected together with P. glossodon , but is more abundant than the latter.

Etymology. Named in honor of Yusuke Yamanoue, Tokyo ( Japan), for his many contributions to the knowledge of acropomatid fishes. He also recognized that these fishes might represent an undescribed species.

Figures

FIGURE 7 A – Q. Head profiles of Parascombrops, Caraibops, Kaperangus, Synagrops and Ƒerilus pseudomicrolepis. A, Parascombrops analis, MNHN 1998 - 1056, 82 mm SL; B, Parascombrops argyreus, ZMUC P 44272, 122 mm SL; C, Parascombrops glossodon n. sp., BMNH 1986.10. 9.79. 85, paratype, 4 mm SL; D, Parascombrops madagascariensis n. sp., MNHN 2008 - 1769, holotype, 68.5 mm SL; E, Parascombrops mochizukii n. sp., NMMBA-P 782, holotype, 166 mm SL; F, Parascombrops nakayamai n. sp., BSKU 102255, holotype, SL 97 mm; G, Parascombrops ohei n. sp., BSKU 72614, holotype, 75 mm SL; H, Parascombrops parvidens n. sp., BSKU 98886, holotype, 57.5 mm SL; I, Parascombrops pellucidus, USNM 44428, 64.5 mm SL; J, Parascombrops philippinensis, ZMA 112.453 (paralectotype of P. malyanus), 52 mm SL; K, Parascombrops serratospinosus, CAS 238016, 67.5 mm SL; L, Parascombrops spinosus, USNM 395230, 95.5 mm SL; M, Parascombrops yamanouei n. sp., NMMB-P 23097, paratype, 70 mm SL; N, Caraibops trispinosus, CAS 61040, 97.5 mm SL; O, Kaperangus microlepis, CAS 222834, 78.5 mm SL; P, Synagrops japonicus, ZMUC P 44324, 159 mm SL; 7 Q, Ƒerilus pseudomicrolpis, CAS 61164, 91 mm SL.

FIGURE 10 A – H. Dentition of vomer, palatines and ectopterygoids: A, Parascombrops pellucidus, USNM 392727, 84 mm SL; B, Parascombrops philippinensis, BMNH 2016.9. 14.1, paralectotype, 74 mm SL; C, Parascombrops serratospinosus, BSKU 16827, 67 mm SL; 10 D, Parascombrops spinosus, MNHN 1989 - 0411, 82 mm SL; E, Kaperangus microlepis, CAS 222834, 96.5 mm SL; F, Parascombrops yamanouei n. sp., NMMB-P 11343, paratype, 82 mm SL; G, Caraibops trispinosus, CAS 61040, 97.5 mm SL; H, Ƒerilus pseudomicrolepis, CAS 61164, 91 mm SL.

FIGURE 13 A – Q. Anal-fin pterygiophores and shape of large first anal-fin pterygiophore of genera Parascombrops, Caraibops, Kaperangus, Synagrops and of Ƒerilus pseudomicrolepis. A, Parascombrops analis, BSKU 94343, 74.5 mm SL; B, Parascombrops argyreus, AMS I. 42758 - 006, 120 mm SL; C, Parascombrops glossodon n. sp., USNM 436684, paratype, 73 mm SL; D, Parascombrops madagascariensis n. sp., MNHN 2008 - 1769, holotype, 68.5 mm SL; E, Parascombrops mochizukii n. sp., NMMBA-P 3887, paratype, 98 mm SL; F, Parascombrops nakayamai n. sp., BSKU 102255, holotype, 97 mm SL; G, Parascombrops ohei n. sp., BSKU 72614, holotype, 75 mm SL; H, Parascombrops parvidens n. sp., BSKU 15219, paratype, 70 mm SL; I, Parascombrops pellucidus, USNM 44428, 65.5 mm SL; J, Parascombrops philippinensis, BMNH 2016.9. 14.1, paralectotype, 64 mm SL; K, Parascombrops serratospinosus, CAS 238016, 67.5 mm SL; L, Parascombrops spinosus, MNHN 1989 - 0411, 82 mm SL; M, Parascombrops yamanouei n. sp., NMMB-P 15571, paratype, 102 mm SL; N, Caraibops trispinosus, CAS 61040, 97.5 mm SL; O, Kaperangus microlepis, CAS 222834, 78.5 mm SL; P, Synagrops japonicus, MNHN 1998 - 0993, 84 mm SL; Q, Ƒerilus pseudomicrolpis, CAS 61164, 91 mm SL.

FIGURE 15 A – AC. Otoliths (inner faces and representative ventral views): A – F, Parascombrops pellucidus (A – C = BMNH 1939.5.24.892 - 894, D – F = BMNH 1939.5.24.880 - 891); G – L, Parascombrops philippinensis (G – H = NSMT-P 59313, I = BSKU 116496, J = NSMT-P 57379, K – L = ZMA 112. 454, Synagrops malayanus paralectotype); M – O, Parascombrops spinosus (M – N = MCZ 169467, O = USNM 395230); P – R, Parascombrops serratospinosus (USNM 99324); S – U, Parascombrops yamanouei n. sp. (NMMB-P 23097); V – X, Caraibops trispinosus (15 V – W = USNM 407771, 15 X = USNM 407745); Y – AA, Kaperangus microlepis (CAS 222834); AB – AC, Ƒerilus pseudomicrolepis (USNM 407758).