Ancistrolepis, DALL, 1895

Squires, Richard L., 2022, The earliest Ancistrolepis (Gastropoda: Buccinidae) and its geologic implications, PaleoBios 39 (2), pp. 1-11 : 5

ANCISTROLEPIS DALL, 1895 SENSU STRICTO

Type species— By original designation. Chrysodomus eucosmius Dall, 1891 . Dall (1891) did not figure the type species of this genus, but Dall (1895: pl. 29, fig. 7) provided an apertural view. Egorov and Barsukov (1994) provided a synonymy of Ancistrolepis eucosmius (Dall) . The type species is extant and lives in deep, cold waters in the following areas: Bering Sea area ( Dall 1891), north of Unalaska in the Bering Sea ( Dall 1891), off the coast of Oregon ( Dall 1895), and off San Digeo, southern California ( Dall 1895, 1919, 1925).

Geologic range of genus— Late early Eocene (late Ypresian Stage = early “Domengine Stage”), Ventura County, southern California (new information) to Recent: from the South China Sea to the East China Sea, the Sea of Japan, Kurile Islands, Sea of Okhotsk, Bering Sea, Aleutian Islands, southern Alaska ( Egorov and Barsukov 1994), as well as Washington, Oregon, and off the coast of San Diego, southernmost California ( Dall, 1895, 1919, 1925).

Differential diagnosis— Protoconch low (one to two whorls), smooth. Teleoconch small to medium size (height range 25 to 135 mm). Fusiform to elongate fusiform and with approximately six to eight convex whorls. Whorls can be rounded or shouldered. Spire approximately 50 percent or less of shell height. Sculpture mostly spiral ribs (rarely nodular locally) or cords, can be relatively few (on upper spire) or moderately numerous, triangular to square, thin to moderately thick (keel-like), interspaces somewhat narrow to moderately wide, commonly flat-bottomed. Sutural area impressed. Axial sculpture mostly only growth lines. Last whorl approximately 50 percent or more of shell height. Aperture moderately wide, interior smooth or showing spiral impressions. Columella smooth. Outer lip entire or marginated, rarely thickened. Siphonal canal short and twisted backward, slightly or somewhat strongly. Radula hamiglossate. Periostracum well developed, can be hairy, and with well developed and numerous growth lines. Operculum horny (can be substantially smaller than aperture width).

Remarks— The name Ancistrolepis is feminine and derived from Greek: ankriston, for fishhook and lepis for scale.