Imparidentia, Bieler, P. M. Mikkelsen & Giribet, 2014

Superorder Imparidentia View in CoL Order Lucinida

Superfamily Lucinoidea Family Lucinidae Genus Lucinoma Dall, 1901

Lucinoma apocalyptica new species ( Fig. 57 View Figure 57 ) https://zoobank.org/ FCF81E9E-956D-43D3-9FE3-39799DA3A13B

Type: Holotype MZSP 162656 View Materials , shell.

Type locality: BRAZIL. Pará ; off Salinópolis, 01°04′N 46°18′W, 250 m [Femorale-Ex collection Vanin; RV Oregon col., o.t., xi.1957] GoogleMaps .

Diagnosis: N Brazilian species of large size (~ 80 mm), thick walled. Sculpture simple, uniform, lacking undulations, carina or abrupt slope. Outline rounded. Umbo broad.

Description: Shell ( Fig. 57 View Figure 57 ), of ~ 80 mm; outline rounded; walls heavy, thick. Color white, opaque. Maximum inflation ~half length ( Fig. 57C View Figure 57 ). Umbones central, slightly prosocline,anterior to it slightly concave edges,posterior to it slightly convex edges. Anterior, ventral and posterior edges performing soft rounded profile ( Fig. 57A, B, D, E View Figure 57 ); posterior slope very weakly undulated, less acuminated than anterior region. Sculpture concentric, low scales, rather irregular, discontinuous; interspaces equivalent to 3-4 times each scales′ width; sculpture uniform from umbo up to margins ( Fig. 57A, B View Figure 57 ). Pre-umbonal lunula present ( Fig. 57C View Figure 57 ), sculptures only by very narrow,crowd- ed, longitudinal lines. Ligament wide, mostly external, almost half of dorsal edge ( Fig. 57C View Figure 57 ). Hinge ( Fig. 57 View Figure 57 F-H) thick, ~8% of shell height; with pair of cardinal teeth in both valves, being anterior most tooth in right valve; posterior tooth in right valve and anterior tooth of left valve slightly bifid; weak anterior lateral tooth present, clearer in right valve ( Fig. 57G, H View Figure 57 ); no detectable posterior lateral tooth. Ligament groove wide, from umbo up to almost posterior edge. Scar of anterior adductor muscle elongated, ~7 times longer than wide, situated ~18° in relation to vertical axis, ~13° in relation to adjacent pallial line. inner surface pure white, barely radially beaded ( Fig. 57D, E View Figure 57 ). Scar of posterior adductor muscle elliptic, ~1.5 times longer than wide, with ~half of anterior muscle′s size. Scar of anterior pedal retractor muscle just superior and posterior to scar of anterior adductor muscle, rather rectangular, ~20 times smaller than adductor muscle. Pallial line complete, wide, anterior half nodulous; its anterior insertion in dorso-anterior edge of anterior adductor muscle edge; its posterior insertion in ventral end of posterior adductor muscle.

Etymology: The specific epithet is based on the Church Latin ‘apocalypsis,′ meaning "revelation, disclosure," as well as from Greek ‘apokalyptein,′ meaning "uncover, disclose, reveal," being an allusion to a large specimen being so far undiscovered in the north Brazilian deep waters.

Distribution: So far known from the type locality.