RESUMO
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.
Assuntos
Anostraca/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Anostraca/anatomia & histologia , Anostraca/crescimento & desenvolvimento , Argentina , Tamanho Corporal , Feminino , Masculino , Tamanho do ÓrgãoRESUMO
Branchinecta uruguayensis, a new species of fairy shrimp, is described from a single seasonally astatic aquatic habitat in coastal Uruguay. This is the first record of an anostracan from the nation of Uruguay. Male B. uruguayensis n. sp. are separated from other Branchinecta species by the form of the second antennae. Branchinecta uruguayensis n. sp. share the distal antennomere lobiform projection with B. papillata Rogers, De los Rios, & Zúñiga, 2008 and B. achalensis César, 1985. Branchinecta uruguayensis n. sp. females are readily separated from all other Branchinecta by the presence of posteriolateral thoracic spines and lateral crenulations on the first abdomen segment margins. A key is provided to the Branchinectidae of South America.
Assuntos
Anostraca/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Anostraca/anatomia & histologia , Anostraca/crescimento & desenvolvimento , Tamanho Corporal , Ecossistema , Feminino , Masculino , Tamanho do Órgão , UruguaiRESUMO
The genus Dendrocephalus Daday, 1908 consists of 17 described species. The morphology of the frontal appendage and the first pairs of thoracopods of males are the main characteristics used for species identification. The objectives of this study were to increase knowledge of the morphology of Dendrocephalus orientalis and to propose a new identification key for the species occurring in Brazil. Specimens were collected in temporary ponds within the conservation unit Monument Natural Grota do Angico (MNGA), which straddles the borders of the municipalities of Poço Redondo and Canindé de São Francisco, State of Sergipe, Brazil. During the study period, 560 male individuals of D. orientalis were sampled. The specimens showed variations in the number of spines on the eyes and the proximal surface of the male frontal appendage. On the eye, the number of spines ranged from 0 to 2; morphotypes with 1 and 2 spines predominated in the samples, with 50.5% and 46.2%, respectively. The number of spines on each eye was the same within each individual. On the proximal surface of the males frontal appendage the following numbers of spines on each arm were recorded: 1 and 1 (57.86%); 2 and 1 (30.89%); 2 and 2 (9.46%); 1 and 0 (1.25%); 3 and 2 (0.36%); 2 and 0 (0.18%). Based on these variations, we conclude that the number of spines on the eyes and the frontal appendage arms cannot be used as a diagnostic character for species identification. On the other hand, the first pairs of thoracopods and sub-branches 1V and 2A of the frontal appendage should be included in keys, since these structures did not show significant intraspecific morphological variation.