Synagrops Günther, 1887

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 : 56-58

Genus Synagrops Günther, 1887

Figs. 1B , 3C, H , 7P , 13P , 31 , Table 1

Type-species: Melanostoma japonicum Döderlein, 1883

Melanostoma Döderlein, 1883 (type-species: Melanostoma japonicum Döderlein, 1883 ; preoccupied by Melanostoma Schiner, 1860 in Diptera )

Hypoclidonia Goode & Bean, 1896 (type-species: Hypoclidonia bella Goode & Bean, 1896 )

Diagnosis. A genus of the family Acropomatidae characterized by the following combination of characters. Pelvic fin spine smooth. First dorsal fin with 9 spines, all visible externally; second dorsal fin I + 9, anal fin II + 7; all spines smooth. Three supraneurals; predorsal formula 0/0/0+2/. No vacant interneural gap below D1. Distal element of last D1 pterygiophore enlarged. Cranial crests strong, W-shaped. Top of head naked. Large cup-like basioccipital fossa extending to the ventral part of the exoccipital receiving anterior portion of swimbladder; myodome opened posteriorly at the parasphenoid flanges. Ectopterygoid toothed, with 2–5 rows of denticles, increasing in width with size. Preopercle without denticles at inner margin and crossed by 1–3 strong ridges. Proximal-middle radial of first anal-fin pterygiophore broad, distinctly bent forwards, with blunt tip, hollow, reaching first haemal spine. First epural bent anteriad, retaining ample space between neural processes of 2nd and 3rd preural vertebrae. Otoliths subrectangular in outline, with depressed small ostium, which is dorsally and ventrally widened towards collum but includes a reduced triangular colliculum, and cauda inclined upwards and with distinct bent at tip.

Discussion. Synagrops differs from all other genera by the presence of basiocciptal fossa, otophysic connection and posterior openings of the myodome, and in its distinctive otolith morphology ( Fig. 1B ). Synagrops shares the same cranial and otolith modifications with Apogonops , Doederleinia and Neoscombrops cynodon ; however, only N. cynodon possesses a similarly deep and extensive basioccipital fossa and posterior openings of the myodome. Synagrops differs from N. cynodon in the lower number of anal-fin spines (2 vs 3), top of the head naked (vs scaled), the enlarged distal element of the last D1 pterygiophore (vs short and small), and in the much stronger jaw dentition. The level of differences and interrelationships of these taxa require further investigation, and is beyond the scope of the present paper, but will be covered in a forthcoming paper. Synagrops further differs from Parascombrops in the pelvic-fin spine being smooth (vs serrated), in the absence of the vacant interneural gap under D1 (vs 8th interneural gap being vacant), and in the predorsal formula (0/0/+2/ vs /0+0/0+2/). Synagrops additionally differs from Caraibops n. gen. in the pelvic-fin spine is smooth (vs serrated), in the much stronger cranial crests, in the toothed ectopterygoid, in the higher number of visible spines in D1 (9 vs 8) and the anal-fin formula, II + 7 (vs III + 9). Synagrops differs from Kaperangus n. gen. in the predorsal formula 0/0/+2/ (vs /0/0+2/), in the strong W-shaped cranial crests (vs weak U-shaped), in the number of the branched anal-fin rays, 7 (vs 9), in the enlarged distal element of the last D1 pterygiophore (vs small) and in the epural pattern (see Figs. 3C, H ).

Species and distribution. Two nominal species are currently recognized ( Eschmeyer 2016): S. japonicus ( Döderlein, 1883) ( Fig. 30 ) ( S. natalensis Gilchrist, 1922 as a synonym) from the Indo-West Pacific eastward to Samoa and S. bellus ( Goode & Bean, 1896) from the Atlantic. A revision of these species will be a part of forthcoming paper.

Material examined (67 specimens): CAS 61035, 5 specimens, 80–119 mm SL, CAS 61040, 97.5 mm SL, CAS 61041, 4 specimens, 81–104 mm SL, 18°13’N, 67°18’W, 356–384 m, 21. Aug. 1987; USNM 159346, 2 specimens, 110–113 mm SL, 07°37’N, 54°43’W, 475 m; USNM 407745, 78 mm SL, off Honduras ; USNM 436688, 103 mm SL, 07°15’N, 53°25’W, 210 m; IOM, uncatalogued, 35 mm SL (cleared & stained), 41˚31΄N, 61˚ 28΄W, pelagic trawl, 50 m; IOM 257, 10 specimens, 133–192 mm SL, 12°32΄–12°25΄S, 48°06΄–48°08΄E, 700–710 m; IOM 258, 120 mm SL, 08°47΄–08°50΄S, 59°55΄–59°49΄E, 525–530 m; IOM 1764, 150 mm SL, 12°18΄–12°14΄N, 53°09΄–53°06΄E, 375–380 m; IOM 1773, 6 specimens, 102–162 mm SL, 22°19΄–22°23΄S, 43°06΄–43°06΄E, 330–335 m; IOM 1845, 21 specimens, 120–165 mm SL, 25°29΄–25°35΄S, 35°09΄–35°01΄E, 490–535 m; IOM, uncatalogued, 8 specimens, 72–95 mm SL, Nha Trang Bay, Vietnam ; MNHN 1998-0993, 2 specimens, 78.5– 84 mm SL, 16°33’S, 167°55’E, 602–620 m; ZMMGU 13103, 180 mm SL, 18°48’S, 149°58’E; ZMUC P44324-25, 2 specimens, 159 and 73 mm SL, Mimase fish market, Kochi, Japan.

Figures

FIGURE 1 A – E. Skull and otolith morphology: A, basicranium of Synagrops japonicus, IOM 1773, showing strongly developed basioccipital fossae (bof) and posterior openings of the myodome (pom); B, basicranium of Apogonops anomalus, IOM uncatalogued, 33 ° S, 127 ° E, showing weakly developed basioccipital fossae (bof) and lacking posterior openings of the myodome; C, basicranium of Parascombrops philippinensis, IOM uncatalogued, Nha Trang Bay, showing absence of the basioccipital fossae and posterior openings of the myodome; D – E, examples of the two principle otolith morpho-types found in Acropomatidae: D, Synagrops; E, Parascombrops.

FIGURE 3 A – J. Predorsal formulae, pterygiophore / interneural patterns and epural patterns: A, pterygiophore pattern with last D 1 spine and its pterygiophore aligned, last D 1 pterygiophore unmodified with short posterior portion of proximal-medial element, short distal element, and interneural gap absent (Kaperangus microlepis n. gen., CAS 223183, 110 mm SL); B, pterygiophore pattern with anteriorly shifted last D 1 spine, with strongly inclined last D 1 pterygiophore with extended posterior portion of proximal-medial element and elongated distal element, interneural gap present (Parascombrops nakayamai n. sp., BSKU 102255, holotype, SL 97 mm); C, predorsal formula 0 / 0 / 0 + 2 / (Synagrops japonicus, MNHN 1998 - 0993, 84 mm SL); D, predorsal formula / 0 + 0 / 0 + 2 / (Parascombrops glossodon n. sp., USNM 99335, paratype, 64.5 mm SL); E, predorsal formula / 0 / 0 + 2 / (Kaperangus microlepis n. gen., CAS 222834, 78.5 mm SL); F, epural pattern with long, straight 1 st epural (Kaperangus microlepis n. gen., CAS 222834, 78.5 mm SL); G – H, epural pattern with short, curved 1 st epural (G = Parascombrops ohei n. sp., BSKU 72614, holotype, 75 mm SL; H = Synagrops bellus, USNM 436688, SL 103 mm); I, 2 nd and 3 rd anal pterygiopjore separated by 2 nd haemal spine (Kaperangus microlepis n. gen., CAS 222834, 78.5 mm SL); J, 2 nd and 3 rd anal-fin pterygiophore corresponding to 1 st interhaemal space (Parascombrops pellucidus, USNM 44428, 62.5 mm SL). Abbreviations: DE, distal element of last D 1 pterygiophore; ppMPE, posterior portion of proximal-medial element of last D 1 pterygiophore.

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 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 30 A – B. Parascombrops yamanouei n. sp.; NMMB-P. 13850, holotype, 99 mm SL.

FIGURE 31 A – B. Synagrops japonicus (Döderlein, 1883); ZMUC P 44324, 159 mm SL.