Periploma skoglundae Valentich-Scott & Coan, new species

Figures 1 A–G

Periploma margaritaceum (Lamarck), auctt., non Corbula margaritacea Lamarck, 1801: 137; P. margaritaceum Lamarck: Bernard, 1989: 3 –4; P. margaritaceum Lamarck: Skoglund, 1991: 53.

Description. Shell ovate-elongate; right valve much more inflated than left; left valve fitting well inside right valve; anterior end broadly to sharply rounded; inequilateral, anterior end much longer; posterior end truncate, with broad, deep radial sulcus, more prominent in right valve; sculpture of fine commarginally arranged granules, densely pustulose posterior to sulcus; pallial sinus moderately wide and deep, extending past beaks; chondrophore moderately small, narrow, anteriorly directed; lithodesma small, narrow, just anterior of chondrophore. Length to 12 mm [SBMNH].

Type material. SBMNH 83429, holotype, paired valves; length, 11 mm; height, 7 mm; paratypes, SBMNH 14601, 1 pair valves from holotype lot; SBMNH 149603, 3 paired valves, 9 single valves from type locality. Additional paratypes from Caleta de los Angeles, Jalisco, Mexico; 19°18'11"N, 104°49'52"W; 6–20 m: SBMNH 149602, 3 paired valves, 22 single valves; UNSM 1146206, 1 paired valves, 2 single valves; CAS 184227, 1 paired valves, 2 valves; LACM 3136, 1 paired valves, 2 single valves.

Type locality. Bahía Chamela, Jalisco, Mexico; 19°33’N, 105°07’W; 12–18 m; mud.

Etymology. Named in honor of Carol Skoglund of Phoenix, Arizona, who has continually advanced our understanding of the Panamic Mollusca for the past four decades.

Distribution. Punta Raza, Nayarit (21.0°N) [SBMNH], to Bahía Cuastecomate, Jalisco (19.2°N) [SBMNH], Mexico; 2–33 m [SBMNH], mud.

Comparisons. Initially reported by Bernard (1989) from the eastern Pacific as the western Atlantic type species of the genus, P. margaritacea (Lamarck, 1801) (Figures 1 H–I), this new species differs from it in having a prominent posterior radial sulcus, a wider, deeper pallial sinus, and lacking an escutcheon. The western Atlantic species is well figured in Mikkelsen & Bieler (2007: 196).

Literature. F. R. Bernard (1989, 3–4, as P. margaritaceum), Skoglund (1991, as P. margaritaceum).