Radiolucina amianta (Dall, 1901)

Garfinkle, Elizabeth A. R., 2012, A review of North American Recent Radiolucina (Bivalvia, Lucinidae) with the description of a new species, ZooKeys 205, pp. 19-31 : 21

Radiolucina amianta (Dall, 1901) Figures 1, 4, 5a

Phacoides (Bellucina) amiantus Dall, 1901: 826-827.

Parvilucina (Radiolucina) amianta . - Britton, 1972: 9-10

Lucina (Bellucina) amiantus Bretsky. - 1976: 273

Shell shape.

Subovate, extended anteriorly and posteriorly, length longer than height, slightly inflated; maximum length: 6.0 mm, maximum height: 6.0 mm.

Sculpture and color.

About 11 (n=2) non-bifurcating radial ribs, overlain by thin commarginal lamellae that continue through interspaces, producing a reticulate pattern; occasional intercalary ribs present; interspaces shallow, thin towards beak and progressively widening ventrally; anterior and posterior ends smooth with fine commarginal striae, posterior sometimes with spines of varying heights protruding from shell; inner shell margin finely crenulate; interior color tan, shiny.

Hinge.

Hinge plate thick, curved on either side of cardinal teeth; beaks prosogyrate; cardinal teeth small, right valve posterior tooth thin, anterior tooth thick, left valve middle tooth wide; lateral teeth large, posterior tooth vertical, anterior tooth horizontal; ligament sunken above cardinal teeth.

Adductor scars and pallial line.

Pallial line continuous; anterior adductor scar long, narrow, diverging from pallial line for about a quarter of its length; posterior adductor scar small, wide, pallial line joins at most ventral point.

Type specimens and type locality.

Dall did not designate a single specimen as the holotype. To stabilize nomenclature, I herein designate the lectotype to be the right valve (USNM 64276), which is the same specimen as figured by Dall 1901, plate XXXIX fig. 10, with the type locality of Yucatan Strait, North Atlantic Ocean (approximately 21.3°N, 86.2°W), 1170 m (Fig. 4). An additional right valve (USNM 1183662) in the original lot is a paralectotype.

Distribution.

Western Atlantic from North Carolina to Florida, West Indies, Gulf of Mexico, Caribbean Central America, South America south to Uruguay ( Mikkelsen and Bieler 2007).

Remarks.

In describing Phacoides (Bellucina) amiantus , Dall noted that it seemed to be the same species that Tuomey and Holmes (1857) had described as Lucina costata from the Pleistocene of South Carolina (non Lucina costata d’Orbigny, 1846). Boss et al. (1968: 25) misinterpreted Dall’s proposal as a new name, but it is expressly a new species. Moreover, it is not at all clear that these represent the same species.

Literature.

Dall (1901), Bretsky (1976), Mikkelsen and Bieler (2007), Tunnell et al. (2010).