ABSTRACT
South American species of Branchinecta that inhabit high altitude biotopes are so far represented by B. brushi and B. papillata. Here we describe a new species inhabiting these extreme habitats, B. piurae sp. nov., whose closest species is B. papillata. Differential characters of B. piurae are the lack, in males, of proximal and distal anteromedial bulges with spines at the second antenna basal antennomere which are conversely present in males of B. papillata; instead, the males of B. piurae have scattered, triangular spines over the anterior and medial surfaces at the distal half of the basal antennomere. In females of B. piurae, the dorsal surface of thoracic segments are provided with well-marked rough protuberances mainly on segments 3 to 10, features that are not observed in B. papillata. As far as is known, Branchinecta piurae sp. nov. is endemic to the Peruvian and Ecuadorian Andes, appearing at altitudes around 3,7003,800 m a.s.l, and latitudes from 247 to 504 S. The results of the genetic analyses based both on mitochondrial and nuclear markers provide a clear support for the morphological description of B. piurae as a new species. We also provide genetic sequences of B. papillata, B. ferox from Spain and B. orientalis from Spain and Mongolia, and show that Palaearctic Branchinecta species are not directly related to B. piurae and B. papillata. In the phylogeny derived from COI, the last two species form a sister clade to the American Branchinecta clade, including several North American species, or in the 16S phylogeny, only B. papillata is at the base. Our results suggest a different history about the genus in America than previous hypotheses. New molecular studies are needed that include additional South American species in order to better explore the diversity and biogeographical patterns of the genus Branchinecta.
Subject(s)
Anostraca , Crustacea , Animals , Anostraca/anatomy & histology , Ecosystem , Female , Male , Peru , PhylogenyABSTRACT
A detailed morphological comparison was carried out among specimens of several samples of Archaebranchinecta Rogers Coronel, 2011 from the Altiplano of Peru, Bolivia, and Argentina. Surprisingly, striking differences were found between Peruvian samples collected near the western shore of Lake Titicaca, and those from Bolivia taken southwardly, near the east coasts of River Desaguadero and Lake Poopó. Accordingly, the new species Archaebranchinecta aimara sp. nov. is described, representing the second specific entity of a genus that so far included only A. pollicifera (Harding, 1940). The main differential features between both species include: (a) size and shape of the three processes of basal segment of the male second antenna; (b) shape and protrusion degree of the pair of medioventral bulges in the male genital segments; (c) presence or absence of strong ventrolateral spine on the second genital segment of female; and (d) presence or absence of a pair of ventrolateral outgrowths in the brood pouch. This research contributes to our understanding of the biodiversity and endemism of the unique Altiplano region of South America.
Subject(s)
Anostraca , Animals , Argentina , Bolivia , Female , Male , Peru , South AmericaABSTRACT
As part of preparation for identification keys to the branchiopod crustaceans of the Neotropical Region, we re-examined many species of Anostraca that appeared to be closely related. Our examination caused us to re-evaluate the status and relationship of two branchinectid species.
Subject(s)
Anostraca , Crustacea , AnimalsABSTRACT
Thamnocephalus chacosaltensis, a new species of fairy shrimp, was found in a temporary turbid pond in the Rivadavia Department, Salta province, Argentina (24º13'19.3''S; 62º 52'14.3''W), belonging to the Chaco salteño. The males present a well developed frontal appendage. Their First (FB) and Third (TB) branches show features diagnostic for the species. FB shows three sub-branches; the most proximal one is coiled, lacks spines all along, gradually thins in distal direction and flattens in the distal half; distally, the flattened portion is folded and ends blunt, bearing a small spine at the tip. TB is a broad-based triangular, thin, much flattened and folded outgrowth, with a small spine at the apex. Male genital and abdominal segments lack medio-ventral spines near their posterior margins. Comparisons with the other species of the genus are established.