Gomphinella habei
Similar to Gomphina undulosa. Gomphinella habei is distinguishable by its more trigonal shape, slightly more inflated valves and overall smaller size. G. habei is also typically found in China and Japan; whereas, G. undulosa has only reliably been found in Australia (Huber 2010).
The overall shape is trigonal ovate. The anterior margin is slightly more pointed than the posterior margin. The anterior dorsal margin is nearly straight, and the posterior dorsal margin is subconvex. The valves are equal in size and shape (equivalve), and there is no gape when they are closed. Sculpture consists of growth lines. There may also be weak comarginal ribs present ventrally. The lunule is very light impressed, defined by a fine shallow groove and covers the anterior dorsal margin. The umbo is very slightly anterior, and the beaks also point slightly to the anterior. The escutcheon is not well defined.
The exterior color is white and there is typically light brown, very fine tent marks. The interior is white.
The ligament is external and supported by nymphal ridges. On the left valve, there are three cardinal teeth (2a, 2b, 4b), none of which are bifid. The posterior tooth (4b) is fused with the nymph, and the shallow groove between the nymph and appressed tooth has a rugose texture. There are three cardinal teeth on the right valve (3a, 1, 3b), none of which are bifid. The nymph has a rugose texture on the right valve. There are no lateral teeth on either valve. The anterior and posterior adductor muscle scars are similar in size and shape. The pallial sinus is rounded and extends to the posterior end of the nymph in length.