Cardita sp. indet.

Figures 284-286

1992. Carditidae sp., Kase and Hayami, Jour. Moll. Studies, vol.58, p.448, listed.

Several dead specimens (UMUT RM19525) of another carditid were obtained from the bottom sediments of "Shodokutsu" of Ie Islet of Okinawa.

In the spinose radial ribs this species resembles Cardita uruma sp. nov. but is easily distinguishable from that species by the weaker shell convexity, subovate outline, absence of ventral indentation, broader radial ribs, smaller umbo and shorter cardinal teeth 3b and 4b. It is possible that they represent juvenile individuals of some noncryptic species of Cardita, but the shell conveity is weaker and the Pd I is larger (ranging 165-176 (µm in maimum diameter) than the known Cardita species around this cave.

Subfamily Carditellinae Iredale and McMichael, 1962

Genus Carditella Smith, 1881

Carditella, as defined by Chavan in Cox et al. (1969), seems to include several small carditids mainly from lower sublittoral substrata of the Indo-Pacific low-middle latitudinal regions. Recently numerous individuals of two minute species, which probably belong to this genus, have been found alive on calcareous muddy sediments in the innermost part of sublittoral caves of Okinawa.