Intraspecific variation inAegla longirostri(Crustacea: Decapoda: Anomura) revealed by geometric morphometrics: evidence for ongoing speciation?

Abstract

Genetic divergences among populations of Aegla longirostri suggest that this group may be formed by cryptic species. In this study, we analysed the carapace shape of six populations of A. longirostri from southern Brazil, using a geometric morphometric approach, to better elucidate the species' systematics. Our results were congruent with the genetic data, meaning that genetically differentiated populations were also morphogeometrically differentiated. The geometric morphometric descriptors showed significant differences in carapace shape among all populations. Geographical distance and isolation may be affecting the gene flow between populations, leading to divergence in both genetic and morphometric traits. Our data indicate the possible existence of cryptic species within A. longirostri, or an incomplete process of speciation. Geometric morphometric methods were efficient in differentiating among populations that do not show divergence in diagnostic characters.

Diversity and conservation status of Aegla spp. (Anomura, Aeglidae): an update

“…It should also be taken into account that many aeglid species present a narrow distribution, and two species with a relatively wide distribution, Aegla longirostri Bond-Buckup & Buckup, 1994 and Aegla platensis, may represent a complex of cryptic species as supported by genetic and morphogeometric evidence (BartholomeiSantos et al, 2011;Marchiori et al, 2014;2015). If this is true, so the distribution area of each cryptic species will be narrower than the "grouped" species, which can result in different conservation status for each cryptic species, the reason for which data were considered deficient for these two current recognized species.…”

Population biology of Aegla platensis (Decapoda: Anomura: Aeglidae) in a tributary of the Uruguay River, state of Rio Grande do Sul, Brazil

“…Albeit variation in population parameters is expected, and sampling methods can bias the results, the differences between UB and GB are very marked, eventually presenting differences of over 100% in certain values. If we consider the geographical isolation between the two river basins (SCHWARZBOLD 2010), alongside the evidences for ecological differences, it becomes clear that molecular studies might be the best choice to elucidate if this is a case of ecological differences between populations, or if this a case of cryptic species (MARCHIORI et al 2014).…”

Phylogeography of the Chinese endemic freshwater crab Sinopotamon acutum (Brachyura, Potamidae)

“…, ; Marchiori et al . ). However, it is not known whether river networks and mountains ranges with complex topography impact the phylogeography of inland true freshwater crabs.…”