Morphological and molecular data reveal the cryptic diversity among populations of Aegla paulensis (Decapoda, Anomura, Aeglidae), with descriptions of four new species and comments on dispersal routes and conservation status

Abstract

The taxonomy of the Brazilian aeglid species Aegla paulensis Schmitt, 1942 from two disjunct hydrographic basins is revised using morphological and molecular data. Results show that six disjunctive populations of Aegla paulensis form a species complex. Aegla paulensis sensu stricto is redescribed and Aegla rosanae Campos Jr., 1998 is revalidated. The four remaining populations previously assigned to Aegla paulensis are now recognized as different species, namely Aegla vanini n. sp., Aegla japi n. sp., Aegla jaragua n. sp. and Aegla jundiai n. sp. All new species are described and illustrated and are well supported by both morphological and molecular data. Aegla lancinhas Bond-Buckup & Buckup in Santos et al., 2015, which until recently was confounded with Aegla paulensis s. str., is supported as a valid species. A key to all members of the A. paulensis species complex is provided, and their phylogenetic and biogeographic relationships to other closely related species is discussed.

A new species of stygobitic aeglid from lentic subterranean waters in southeastern Brazil, with an unusual morphological trait: short pleopods in adult males

“…Names and terminology used to describe body parts and appendages, with the exception of the first pair of pereopods, followed Schmitt (1942), Martin andAbele (1988), andBuckup (1994) and Moraes et al (2016). Terminology used to describe the morphology of the first pair of pereopods (chelipeds) followed Martin and Abele (1988) and Moraes et al (2016), in which the relative position of margins and surfaces of segments with respect to the inward rotation of the appendage was observed. Major and minor chelipeds are described separately because they are unequal in size and show morphological differences between them, especially with regard to the three distalmost segments (carpi, propodi and dactyli).…”

“…All measurements and calculation procedures for determining the shape of body parts or structures and appendage segments discriminated below are based on Moraes et al (2016), except when noted.…”

“…Left lateral margin of rostrum (b) (selected for standardization purpose): straight-line distance taken from the apex of rostrum to the left orbital sinus midpoint. Based on the value obtained from the ratio a/b, three sizes of rostrum are recognized (modified from Moraes et al, 2016): long (a/b < 0.95, resembling a narrow base isosceles triangle), regular (0.95 ≤ a/b ≤ 1.05, resembling an equilateral triangle), and short (a/b > 1.05, resembling a wide base isosceles triangle).…”

“…Preparation of the fifth pereiopods for scanning electron microscopy (SEM) followed Moraes et al (2016). Sexual tube observation followed standardized spatial orientation view as recommended by Moraes et al (2016).…”

“…The width of the uropods was based on the ratio between maximum width of the endopod (a) and half the maximum width of telson (b), the latter measurement was taken from anterolateral margin to longitudinal suture [see Moraes et al (2016) for details and figure]. The recognized shapes are: "wide", when a/b ≥ 1.00, and "narrow" when a/b < 1.00.…”