Illustrated key to the Brazilian Dendrocephalus ( Crustacea : Anostraca : Thamnocephalidae )

The Anostraca is a diversified crustacean group inhabiting essentially in temporary wetlands on all continents. The genus Dendrocephalus sensu stricto is endemic to tropical or subtropical Neotropical fresh water pools. Of the 13 described species, four are reported from Brazil. Species identification is based on morphological differences on the complex frontal appendage, the anterior thoracopods, and the gonopods. After a detailed comparison of the different Brazilian populations, we developed an illustrated identification key based on the variations of the frontal appendage. This key includes a new undescribed species recently found in Northern Minas Gerais. We present a simple tool to identify Brazilian Dendrocephalus species in order to encourage more studies on this generally neglected genus.


Introduction
A part of Branchiopoda is typically restricted to temporary pools where they represent a significant part of the biodiversity.The order Anostraca (fairy shrimp) includes more than 300 species belonging to 26 genera (Belk and Brtek, 1997;Brendonck et al., 2008;Rogers, 2009).Three genera are known from Brazil: Artemia Leach, 1819 (Artemiidae), restricted to saline habitats; Branchinecta Verrill, 1869 (Branchinectidae) and Dendrocephalus Daday, 1908 (Thamnocephalidae) from temporary freshwater pools.Dendrocephalus (sometimes referred to as "branchoneta" in Brazilian literature) males have a particularly long and complex cephalic extension, called 1998).Herein, a new as yet undescribed species, recently discovered in Minas Gerais State is reported for the first time.Because the biodiversity of Brazilian anostracans remains relatively unknown, we present an updated Dendrocephalus identification key in order to encourage future studies of these animals.

Results and Discussion
Dendrocephalus frontal appendage morphology provides good characters to separate all Brazilian species already used in the first Brazilian key (Rabet and Thiéry, 1996).We present a new identification key that utilizes the following characters: number of spines (0, 1 or more) at the anterior edge of arms of the frontal appendage; the shape of the anterior part of the sub-branch 1V (extremity inflated or elongated) and also the occurrence of long or short spines on sub-branch I and II of branch 2D.
We included in the key the new undescribed Dendrocephalus species from Minas Gerais.This species sorts out at the same couplet with the other Minas Gerais endemic, D. thieryi.These two species differ by the length of spines on branch 2D.
Only two species are widely distributed species is obviously underestimated because the few number of collections.In Brazil, the genus appears to be restricted to a few localities, corresponding to a small portion of the country, suggesting that more new species should be found especially in the Cerrado biome.
Through this new illustrated identification key, we hope to help non specialists in their identifications of the species  , 1908in Brazil (following: Rabet and Thiéry, 1996, Souza and Camara, 1998;Lopes, 2002;Rabet, 2006 and  collected in Brazilian temporary waters and, by this, to lead to a better understanding of the distribution and the ecology of this genus.This point is particularly important, because these emblematic species are sometimes threatened and in need of conservation (Rogers, 2009).Some other have a great interest in aquaculture and should also be clearly identified (Lopes, 2002).Furthermore, we are convinced that more new Brazilian species will be discovered and described especially in Cerrado's ecosystems.
in Brazil: D. brasiliensis and D. orientalis present in different type of climats, from humid costal climat to semi-arid climat called caatinga.In cerrado, a Brazilian savannah, 3 species are known: D. goaisensis, D. thieryi and the new species.However each of these species seems to have a relatively more restricted distribution indicating that the endemism level of Anostraca are probably more important in Cerrado than in other Brazilian biomes.The diversity of Brazilian Dendrocephalus
Figure 2. Distribution map of the species of Dendrocephalus Daday, 1908 in Brazil (following: Rabet and Thiéry, 1996, Souza and Camara, 1998;Lopes, 2002;Rabet, 2006 and this work).Localities are indicated in the text.Localities indicated from Pesta, 1921 are not enough detailed to be indicated in the map.Symbology: Star = the new species; Triangle = D. brasiliensis; Diamond = D. goaisensis; Oval = D. orientalis and Rectangle = D. thieryi.The grey area shows the location of the "cerrados" (from BIOMAS DO BRASIL: CERRADO.www.wwf.org.brinformacoesquestoes_ambientaisbiomasbioma_cerradomapa_bioma_cerrado).