Kaperangus Prokofiev & Schwarzhans

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 : 15

Genus Kaperangus Prokofiev & Schwarzhans , new genus

Type-species: Synagrops microlepis Norman, 1935

Diagnosis. A genus characterized by the presence of two supraneurals, a predorsal formula of /0/0+2/ and a very thin, flat otolith, with the dorsal rim more strongly bent than the ventral rim; also distinctive is the combination of the following characters: pelvic-fin spine smooth; no basioccipital fossa and no otophysic connection; myodome closed posteriorly; D2 with 10 branched rays; anal-fin rays II + 9; distal element of the last D1 pterygiophore small; no interneural gap below D1; epaxialis attachment type 0; cranial crests U-shaped; preopercle with many denticles at inner margin (6–13) and without crossing ridges; ectopterygoid toothless; first epural straight and densely packed between neural processes of the 2nd and 3rd preural vertebrae.

Discussion. Kaperangus is readily identified by the presence of only two supraneurals and the shape of the thin and flat otolith with its shallow ventral rim, both characters unique amongst acropomatids. The former is considered as a secondary loss, the latter as derived. Kaperangus shares with Caraibops the high number of branched fin rays in the second dorsal (10) and anal (9) fins, but differs in the low number of spines in the anal fin (2 vs 3). It further differs from Caraibops and Parascombrops in having a smooth pelvic-fin spine (vs. serrate), a short and small distal element of the last D1 pterygiophore (vs enlarged and elongated), the epural pattern ( Fig. 3F ), and U-shaped cranial crests (vs W-shaped). It further differs from Caraibops in the sharply denticulated inner preopercular ridge (vs. smooth or nearly so), and from Parascombrops in the absence of the vacant interneural gap under D1 and the ectopterygoid dentition.

Etymology. Derived from the Russian “kaperang”, an abbreviation for the rank of captain required for long range oceanic cruises; and dedicated to the crews of research vessels who have collected so many marine organisms for scientists.

Species and distribution. There is a single extant species, K. microlepis ( Norman, 1935) , known in the Eastern Atlantic from Mauritania to Namibia, at 50–450 m (most abundant at about 200 m) . Otoliths have been found commonly in sea bottom dredges off Guinea to Gabon at depths between 50 and 500 m, with few specimens down to 1500 m ( Schwarzhans 2013). The fossil otolith-based species Parascombrops malzi Schwarzhans, 2010 from the Early and Middle Miocene (Burdigalian and Langhian) of the North Sea Basin is also transferred to Kaperangus and likely represents the direct ancestor in the lineage leading to Recent species.

Figures

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.