Phylogenomic analyses reveals gene flow between populations of the freshwater shrimp Potimirim brasiliana (Caridea, Atyidae) along its wide distribution

Abstract

Potimirim is one of the 40 genera of Atyidae restricted to America, which occurs in coastal freshwater habitats and questions about population status and variability have been emerging. Potimirim brasiliana occurs in Brazil from the northeastern to southeastern region. In order to evaluate the hypothesis of genetic structure among populations, we performed molecular analyses with specimens from all known limit of distribution of the species. The molecular markers used were COI and 28S. Phylogenetic trees were obtained by maximum likelihood and Bayesian analyses, and a haplotype network was obtained based only on COI. We found clear separation between P. brasiliana, P. potimirim, P. glabra and Potimirim sp 2. No pattern of structuration was found among P. brasiliana, but the haplotype network showed geographic pattern of structuration for the congener P. potimirim. The lack of genetic structuration among P. brasiliana can be explained by its life cycle that requires brackish water to complete their larval development. The larvae and juvenile in contact with these habitats can spread through oceanic currents, especially in higher rainfall seasons, maintaining the gene fl ow. The explanation for the geographical pattern found among P. potimirim is still missing and aspects about its lifecycle and larval development should be investigated.

Isotopic signature of the caridean shrimp Potimirim brasiliana Villalobos, 1960 in different points of a pristine area in southeastern Brazil

“…The genus Potimirim Holthuis, 1954 is an excellent group that fits with this later characteristic. This genus has currently five species of tiny freshwater shrimps, all restricted to the American continent (Torati & Mantelatto, 2012;Mantelatto et al, 2021), among which two species occur in coastal rivers and streams of Brazil, P. brasiliana Villalobos, 1959 andP. potimirim (Müller, 1881) (Mantelatto et al, 2021).…”

“…This genus has currently five species of tiny freshwater shrimps, all restricted to the American continent (Torati & Mantelatto, 2012;Mantelatto et al, 2021), among which two species occur in coastal rivers and streams of Brazil, P. brasiliana Villalobos, 1959 andP. potimirim (Müller, 1881) (Mantelatto et al, 2021). These shrimps have a fundamental role in the trophic web Resultados: Nossos resultados mostraram que há um enriquecimento isotópico diferencial ao longo do curso do rio em 13C, fornecendo resultados importantes sobre as condições ambientais e os impactos antropogênicos na região.…”