IDENTIFICATION OF THE LARVA OF PINNA ATRINA JAPONICA (REEVE)

Abstract

In the present paper, shoe-horn shaped and strange bivalve larvae, collected in Ago Bay ?? were studied. They were followed with growing stages and compared with the prodissoconchal shell of young Pinna atrina japonica. Based on the facts obtained in this study, they were identified with the veliger larvae of Pinna atrina japonica.
The veliger larva of this species is very similar in shape to that of allied species, Atrina pectinata japonica, but it can be distinguished from the latter by the following morphological features;
a) Larval shell of Pinna atrina japonica is golden yellow in color.
b) When the veliger gets grown stage, brown spots appear only on the velum in Pinna Atrina japonica, but in Atrina pectinata japonica, black spots appear on the anterior adductor muscle and the proximal part of the foot.
c) Full-grown veliger of Pinna atrina japonica measures about 400μ in shell length, but the same stage of Atrina pectinata japonica attains about 600μ.