MORPHOLOGICAL DIFERENTIATION OF THE SPECIES OF PIANGUA, ANADARA TUBERCULOSA AND ANADARA SIMILIS (ARCIDAE), IN MANGROVE FORESTS THROUGHOUT THE PACIFIC COAST OF COLOMBIA USING GEOMETRIC MORPHOMETRICS

Abstract

The morphological characterization of two piangua species Anadara tuberculosa (Sowerby) and Anadara similis (Adams) was performed using geometric morphometric. Shells of both species were collected in nine different areas of the Colombian Pacific coast during 2009 as part of a project on the natural populations of piangua. The left valve of the shell was used to draw seven landmarks and evaluate the geometric configuration of the shell. Pianguas were grouped based on the mangrove cover of the localities where they were collected. Intra-specific comparison showed that areas where the organisms were collected do not affect valve configuration. Contrarily, centroide size showed significant variation in organism collected in different zones. Differences due to size are not sufficient to determine the existence of different populations, mainly because these differences may happen due to differences in fishery patterns increasing the ratio of smaller sizes. Pacific Ocean current might favor the genetic flux of organisms of both species, limiting the possibility of evolution of independent populations. It is important to complement this study with other investigations in genetics and larval dispersion in order to corroborate our findings.