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Species boundaries in Corbula (Corbulidae: Bivalvia) from South-Southeastern Brazil based on molecular markers

Monica Paiva Quast
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Eliane Pintor de Arruda; Juliana José; José Eduardo Amoroso Rodriguez Marian; Flavio Dias Passos
Advisor: Antonia Cecilia Zacagnini Amaral

Species are fundamental unities in many biological studies and, being so, their identification is essential for researches in many different fields. This task, however, is complicated by badly defined interspecies boundaries, especially in the sea, where cryptic species are quite common. Species delimitation has been receiving much attention, and molecular techniques have been proved of great value to the matter. Corbula (Bivalvia, Corbulidae) is frequent and ecologically important genus in benthic marine communities. Nevertheless, its taxonomy is confusing, in part due to a plastic shell, which makes it difficult to establish species boundaries. This study aimed to analyze the COI and 16S sequences of six morphologically identified Corbula species occurring off the South-Southeastern Brazilian coast. Being a mainly sublittoral genus, most of the analyzed material had been previously sampled, fixed in formalin and preserved in alcohol. Hence, initially specific protocols for DNA extraction and PCR were developed. Better results were obtained with an extraction protocol combining organic extraction and silica adsorption. The nested PCR yielded more product than the direct PCR. Delimitation analyses were conducted with four different methods: two tree based (GMYC and Brownie) and two non-tree based (4x rule and ABGD). Different methods and markers produced different delimitations, but the combined evidence supports the morphological delimitation of three species: Corbula caribaea, Corbula tryoni and Corbula lyoni. Individuals assigned to Corbula patagonica were separated into two molecular species. Only one individual of Corbula aequivalvis was analyzed and it was distinguished from other species. One individual assigned to Corbula sp1 could not be distinguish from C. caribaea. (AU)

FAPESP's process: 07/04712-4 - Species boundaries in Corbula (Corbulidae: Bivalvia) from Brazil based on molecular markers
Grantee:Mônica Paiva Quast
Support type: Scholarships in Brazil - Doctorate