Tellina (Merisca) steinbecki Coan & Valentich-Scott, 2010

Coan, Eugene V. & Valentich-Scott, Paul, 2010, Three new species of Tellina (Bivalvia, Tellinidae) from the Panamic Province, Zootaxa 2715, pp. 55-58 : 56

Tellina (Merisca) steinbecki Coan & Valentich-Scott , new species

Figures 1 M–P, 2 C

Shell ovate-subtrigonal, inequilateral, longer anteriorly (anterior end about 67% of length); posterior slope set off by moderate sulcus in right valve and shallower sulcus in left valve; posterior end not produced, moderately flexed to right, truncate; escutcheon deep, long, narrow; sculpture of dense, irregular commarginal lamellae, with conspicuous radial ribs in larger specimens that make the commarginal lamellae frilly in some places; right valve with very strong anterior and posterior lateral teeth, both distant and equidistant from the cardinal teeth; pallial sinus deep but stopping well short of anterior adductor muscle scar, merged with pallial line for about 70% of length. Length to 26 mm [CAS].

Type material. SBMNH 149550 , holotype; length, 20.5 mm; height, 14.5 mm ; SBMNH 149592 , 56 paratypes, including both paired valves and separate valves; UNSM 1146207, 1 paratypes, 1 set of paired valves and 2 separate valves ; CAS 184229 , paratypes, 1 set of paired and two 2 separate valves ; LACM 3137 , paratypes, 2 separate valves .

Type locality. Off the northeast end of Isla Danzante, Baja California, México ; 25°48’15”N, 111°14’57”W; 200–300 feet [61–91 m].

Etymology. This species is named after John Steinbeck, noted American author who explored the Gulf of California with Ed Ricketts.

Distribution. Bahía Santa Inés, Baja California Sur (27.0°N) [CAS], and Bahía San Carlos, Sonora (27.9°N) [SBMNH], México, to the Golfo de Cupica, Chocó, Colombia (6.4°N) [UMML]; Isla Baltra, Islas Galápagos, Ecuador (0.4°S) [CAS]; 35– 180 m.

Comparisons. Tellina steinbecki has a pallial line similar to that of the Caribbean T. juttingae ( Regteren Altena, 1965) , but that species has a flaring, broadly rounded anterior margin, and has fine commarginal intercalary striae, rather than radial ribs. Of eastern Pacific taxa, it is closest to T. (M.) brevirostris Deshayes, 1855 , but in that species the pallial sinus reaches very close to or fuses with anterior adductor muscle scars in both valves, with no area where sinus parallels pallial line ( Figures 1Q–T). Tellina brevirostris is also more equilateral, the anterior end representing about 60% of the shell length, and the intercalary spaces between the commarginal lamellae have commarginal striae rather than radial ribs.