Identification of Ruditapes philippinarum and Meretrix lusoria larvae using single cell PCR analysis and microscopic observation

Abstract

Single cell PCR analysis and light and scanning electron microscopic techniques were utilized to identify free living bivalve larvae in the coastal waters of Tae-an, on the west coast of Korea. Through DNA sequencing, venerid clam larvae were isolated and identified as Ruditapes philippinarum (99% similarity) and Meretrix lusoria (99%). Under microscopic observation, the D-veliger stage of R. philippinarum exhibited symmetrical shoulder angles and an elliptical ventral form. In contrast, M. lusoria displayed asymmetrical shoulder angles and a round ventral form in the umbonal stage. Size of the R. philippinarum larvae was 156±22 μm in length, 126±12 μm in height, 92±14 μm in width with a length: height ratio of 1.23. Meretrix lusoria was 202±44 μm in length, 161±35 μm in height, 96±38 μm in width with a length: height ratio of 1.25. Experimental results indicate that morphological and molecular characteristics provide evidence for the larval identification of these two venerid clam larvae species in nature.