Hypsocormus Wagner, 1863

Maxwell, Erin E., Lambers, Paul H., López-Arbarello, Adriana & Schweigert, Günter, 2020, Re-evaluation of pachycormid fishes from the Late Jurassic of Southwestern Germany, Acta Palaeontologica Polonica 65 (3), pp. 429-453 : 438

Genus Hypsocormus Wagner, 1863

Type species: Hypsocormus insignis (Wagner, 1860) , Late Jurassic , Bavaria, Germany ( Figs. 4A 1 , 5B 1 ) .

Diagnosis (modified from Woodward 1895).—Fusiform fish, head small (25% SL) and length of skull less than depth of trunk, snout short and obtuse, so2 greatly enlarged at the expense of so1, opercle much larger than subopercle, robust dentition, teeth round to slightly oval in cross-section, ossifications in notochordal sheath absent, dorsal fin base oppositeto completely anterior to the anterior edge of the anal fin, leaflike fringing fulcra on leading edge of caudal fin, pectoral fin gladiform, pelvic fins small and closer to pectoral fins than to anal fin, scales in a 2:1 ratio with axial segments, scaly caudal apparatus consisting of L-shaped scales present.

Remarks.—Under this strict definition, species previously included in Hypsocormus ( H. macrodon and H. tenuirostris ) are excluded; see taxonomic nomenclature section for details.

Figures

Fig. 4. Pachycormid fish Hypsocormus Wagner, 1863 from the Late Jurassic of Germany. A. Hypsocormus insignis (Wagner, 1860) (holotype SNSB-BSPG AS VI 4a, mirrored), Bavaria, Germany. B. Hypsocormus posterodorsalis sp. nov. (holotype GPIT/OS/00836), Nusplingen, Germany. Arrows indicate anterior insertion of median fins.

Fig. 1. Nusplingen and other localities of fossiliferous Late Jurassic Plattenkalks in SW Germany (modified from Fürsich et al. 2007 based on Schweigert 2007).

Fig. 5. Pachycormid fish Hypsocormus Wagner, 1863 from the Late Jurassic of Germany. A. Hypsocormus posterodorsalis sp. nov. (GPIT/OS/00836) from the Kimmeridgian of Nusplingen. Skull preserved in right lateral view, photograph (A1), explanatory drawing (A2). Braincase in lateral view, photograph (A3), explanatory drawing (A4). Anterior skull in ventrolateral view showing the maxillary dentition and the absence of strong tubercular ornamentation on the lateral surface of the maxilla (A5). Posterior dentary teeth, white arrows indicate posterior two tooth positions showing twinning of tooth germ, black arrows indicate small teeth external to main dentary tooth row (A6). Temporal boss in lateral view (A7). B. Hypsocormus insignis Wagner, 1860) (holotype SNSB-BSPG AS VI 4a), dentition in lingual view showing apicobasal ridges (anterior to the left). Abbreviations: an, angular; bo, basi-exoccipital; cl, cleithrum; de, dentary; dpcl, dorsal postcleithrum; dpl, dermopalatine; ecp, ectopterygoid; enp, entopterygoid; fica, foramen for the internal carotid artery; ex,?extrascapular; f.VII?, foramina potentially transmitting the facial nerve; fstIX, foramen for the supratemporal branch of the glossopharyngeal nerve; fsX, foramen for a subsidiary branch of the vagus nerve; hyo, hyomandibula; ic, intercalar; jg, jugular groove; mx, maxilla; oca, occipital arch; oo, opisthotic; op, opercle; op.hyo, opercular process of the hyomandibula; ps, parasphenoid; pt, posttemporal; sc, sensory canal; scl, supracleithrum; sco, scapulocoracoid; vf, vestibular fontanelle; vpcl, ventral postcleithrum; X, formen for the vagus nerve.