Page 230 - The Freshwater Mussels of Oklahoma

Partial Synonymy:
Proptera (Leptodea) amphichaena (Frierson) Branson, 1973
Leptodea amphichaena Frierson, 1898, Branson, 1984
Description:
“Shell large, long elliptical, subinflated, subsolid, with moderately full, but not
high, beaks, whose sculpture has not been seen; with a long, narrow gape on the anterior
base and a most decided one behind just above the posterior point; posterior ridge full,
rounded; surface with irregular growth marks; epidermis dark brown to jet black, smooth
and shining on the middle of the disk, somewhat roughened and lamellar on the rest of
the shell, especially on the posterior slope; left valve with one rather feeble,
subcompressed pseudocardinal and a vestigial second one in front of and below it, with
two short, very remote laterals; right valve with one pseudocardinal, sometimes with a
smaller one above it, and a remote lateral, whose inner edge is curved upward; beak
cavities shallow, with an irregular row of large muscle scars running down towards the
anterior base; anterior scars large, shallow; posterior scars small, somewhat elongated;
pallial line wide, with a distinct sinus behind; nacre bluish and purplish, somewhat
clouded. The female shell differs but slightly from that of the male, being a little fuller
just behind the middle of the base and having the blunt posterior point a trifle higher”
(Simpson, 1914).
Comments:
This species is included because of a single specimen reported by Branson (1973)
from the Mountain Fork River, McCurtain County, Oklahoma. It occurs in the Sabine,
Neches and Trinity Rivers in Texas and could conceivably be present in the southeastern
corner of the state or have been inadvertently introduced from across the Red River.

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