Elongatolucina elassodyseides ( Saul, Squires, and Goedert, 1996 )

Gill, Fiona L. & Little, Crispin T. S., 2013, A new genus of lucinid bivalve from hydrocarbon seeps, Acta Palaeontologica Polonica 58 (3), pp. 573-578 : 574-576

Elongatolucina elassodyseides ( Saul, Squires, and Goedert, 1996)

Fig. 3.

Type locality: CSUN locality 1583, East fork of Humptulips River, Grays Harbour County, southwestern Washington, USA .

Type horizon: Humptulips Formation, Eocene.

Material.— Type (five specimens) and non−type (seven specimens) material of Cryptolucina elassodyseides stored in LACMIP , including holotype LACMIP 11422 and paratypes LACMIP 11423−6 .

http://dx.doi.org/10.4202/app.2011.0092

Amended description.—In addition to the original description we note the following features. In the left valve there is a shallow, triangular−shaped depression underneath the umbo, which extends further to the posterior than the anterior, and causes a deflection in the ventral margin of the hinge plate. The anterior margin of this depression is bounded by a sharp ridge. The exterior shell ornament consists of commarginal growth lines, with fine radial striae in the dorso−anterior area of the paratype LACMIP 11426. The anterior adductor muscle scar is elongate (2.5 to 3 times longer than wide) and detached from the pallial line for 2/3 of its length, with an angle of divergence of approximately 40°. The pedal retractor muscle scar is separated from the anterior adductor muscle scar. The posterior portion of the posterior adductor muscle scar cannot be clearly seen on any of the specimens, so its overall shape cannot be discerned, despite being described as elongate and oval by Saul et al. (1996). Radial striations are present in the umbonal region and extend in the anterior and posterior regions across the adductor muscle scars. The area between the pallial line and the shell margin has a faint suggestion of radial striations and immediately dorsal to the pallial line are a series of digitations. These represent sites of pallial muscle attachment (John Taylor, personal communication 2011).

Geographic and stratigraphic range.— Eocene , Humptulips Formation, Washington State, USA ( CSUN localities 1582, 1583) .