Lithophaga Röding, 1798

Kleemann, Karl, 2007, Catalogue and bibliography of Recent and fossil Botula (Bivalvia: Mytilidae), Zootaxa 1508, pp. 1-48 : 4

Lithophaga Röding, 1798

( Fig. 1 )

Type species. L. mytuloides Röding, 1798 , by monotypy, referring to Gmelin’s (1791: 3351) species 6, Mytilus lithophagus Linnaeus, 1758 .

Diagnosis. Shell cylindrical, posteriorly more compressed, with vertical striae antero-ventrally and lacking any self-deposited calcareous incrustation (subgenus Lithophaga ) or shell smooth and (partly) covered with own incrustations, particularly on the posterior half (subgenus Leiosolenus Carpenter, 1857 ). Umbones subterminal, ligament deep-set, along a toothless hinge.

Remarks. Anal and branchial siphons fused as in Adula , but the branchial part lacks papillae on its edge in Lithophaga . In L. lithophaga , there is a tonguelike structure, the valvular membrane, with minute papillae at the base of the branchial sipho ( List 1902: pl. 7, fig. 6). Some examples of valvular siphonal membranes with central lappet and lateral digits in three L. ( Leiosolenus ) species are figured in Wilson (1985: figs. 5 and 7a, c), those of B. fusca by Wilson & Tait (1984: figs. 4, 5A, B). All seem to be quite variable and, therefore, of no help for species determination.

Figures

FIGURE 1. Shell characters of boring mytilid genera Botula, Lithophaga, Adula, Gregariella, and of non-boring “ Notobotula ”. (a) left lateral view, (b) anterior view, (c) posterior view.