Variación fenotípica de la concha en Neritinidae (Gastropoda: Neritimorpha) en ríos de Puerto Rico

Abstract

Phenotypic variability of the shell in Neritinidae (Gastropoda: Neritimorpha) in Puerto Rican rivers. Gastropods of the Neritinidae family exhibit an amphidromous life cycle and an impressive variability in shell coloration in Puerto Rican streams and rivers. Various nominal species have been described, but Neritina virginea [Linné 1758], N. punctulata [Lamarck 1816] and N. reclivata [Say 1822] are the only broadly reported. However, recent studies have shown that these three species are sympatric at the river scale and that species determination might be difficult due to the presence of intermediate color morphs. Individuals (8 751) were collected from ten rivers across Puerto Rico, and from various segments and habitats in Mameyes River (the most pristine island-wide) during three years (2000)(2001)(2002)(2003), and they were assigned to one of seven phenotypes corresponding to nominal species and morphs (non-nominal species). The "axial lines and dots" morph corresponding to N. reclivata was the most frequent island-wide, while the patelliform N. punctulata was scant, but the only found in headwater reaches. The "yellowish large tongues" phenotype, typical of N. virginea s.s. was the most frequent in the river mouth. The frequency of secondary phenotypes varied broadly among rivers, along the rivers, and among habitats, seemly influenced by salinity and predation gradients. The occurrence of individuals with coloration shifts after predation injuries, suggests phenotypic plasticity in the three nominal species, and urges for the use of molecular markers to unravel the possible occurrence of a species complex, and to understand the genetic basis of polymorphism. The longitudinal distribution of individual sizes, population density and egg capsules suggested the adaptive value of upstream migration, possibly to avoid marine predators. Rev. Biol. Trop. 62 (Suppl. 2): 53-68. Epub 2014 April 01.

Molecular evidences confirm the taxonomic separation of two sympatric congeneric species (Mollusca, Gastropoda, Neritidae, Neritina)

“…Molluscs from the gastropod family Neritidae are the most diverse members of Neritimorpha (Kano et al 2002), with some groups within this family having variable shell colouration patterns (e.g., Russell 1941;Tan and Clements 2008;Eichhorst 2016). Due to the great variety of colour patterns, the delimitation of different species could be hampered, especially if they are closely related and live in sympatry (e.g., Huang 1997;Blanco et al 2014). This may explain the disparate estimates in the literature of the number of species of Neritina reported for the Brazilian Province.…”