Abstract:
Veneridae, commonly known as Venus clams, is the largest family within phylum Bivalvia,
encompassing over 800 species. Recent studies suggest that Veneridae subfamilies exhibit a
high similarity in morphological characters, contributing to the taxonomic confusion within
this diverse group – remaining poorly understood. However, a few studies have begun using
geomorphometric analysis to describe variations in shape and morphology among similar genera
of venerids. As such, this study conducted a preliminary geomorphometric analysis of six
venerid species: Hyphantosoma nancyae, Liconcha philippinarum, Callista erycina, Paphia declivis,
Periglypta puerpera, and Meretrix meretrix. Shell samples were collected from Mindoro
Island, a major shellfish producer in the Philippines. The right valves of thirty to thirty-three
individuals were subjected to landmark digitization to discriminate among and within species.
Thirty-two landmarks were used, fifteen (15) inside and seventeen (17) outlining the shell. The
principal component analysis reveals that the antero-ventral and postero-ventral tips of the anterior
and posterior cardinal teeth and the postero-ventral tip of the pallial sinus account for
the variation inside, while the landmark perpendicular to the junction of the ventral tip of the
anterior adductor muscle scar and the pallial line accounts for the variation outlining the shell.
Moreover, the canonical variance analysis reveals apparent clustering of individuals of the same
species, except for an overlap between C. erycina and P. declivis. The MANOVA also reveals
significant shape variation across all species pairs (p = 6.993E-255 < 0.05). This study represents
the species differences considering the inside and outline of venerid clams. It highlights
the importance of incorporating internal and external shell features for accurate species discrimination
within Veneridae.
