Molecular and morphological discrimination of Taliepus marginatus (Bell, 1836) and T. dentatus (H. Milne Edwards, 1834) (Decapoda: Brachyura: Epialtidae): insights from their larval development

This study provides molecular and morphological evidence supporting the existence of two distinct Taliepus species along the Southeastern Pacific coast, T. dentatus (H. Milne Edwards, 1834) and T. marginatus (Bell, 1836). DNA analysis revealed a significant genetic divergence between the two species, with a 95% similarity in a partial 16S rRNA sequence. The observed genetic distance falls within the expected intrageneric range, confirming the validity of both species. In addition, the complete larval development of T. marginatus is described and illustrated for the first time and compared with that for T. dentatus (by Fagetti & Campodonico 1971). While some morphological differences were observed between the two species, these were minor and may not be sufficient for reliable identification. Identification keys for zoeal and megalopa stages of the subfamily Epialtinae Macleay, 1838 were provided, aiding in the identification of plankton-collected specimens. The limited morphological divergence between the two Taliepus species suggests that speciation may have been driven by ecological and/or environmental factors affecting the adult stage.