First record of the family Thamnocephalidae (Crustacea: Anostraca) from Southeast Asia and description of a new species of Branchinella

During a two-year investigation of freshwater microcrustaceans in Thailand, an undescribed species of fairy shrimp of the genus Branchinella Sayce, 1903 in the family Thamnocephalidae, was discovered. This is the first record of the genus and the family from Southeast Asia and the second anostracan reported from Thailand. The new species, Branchinella thailandensis n. sp. appears to be morphologically intermediate between B. kugenumaensis (Ishikawa, 1895) from Japan and east China, and B. madurai Raj, 1951 from India and Pakistan. B. thailandensis n. sp. was collected from several temporary ponds in 11 provinces of the northeast and the central Thailand, often co-occurring with Streptocephalus sirindhornae Sanoamuang, Murugan, Weekers & Dumont, 2000.     

Comparative reproductive study of two <Emphasis Type="Italic">Streptocephalus sirindhornae</Emphasis> (Branchiopoda: Anostraca) populations and F1 hybrids: a laboratory study

We investigated the effects of inbreeding and crossbreeding on the reproductive biology of two populations of fairy shrimp Streptocephalus sirindhornae from Maha Sarakham (M) and Suphan Buri (S) provinces of Thailand. Four groups of the mature fairy shrimp were experimentally mated; S × S, M × M, M × S and S × M. The data on life span, age at first spawning, number of eggs per brood and total number of eggs per female of the inbred and crossbred parent generations (P) were not significantly different. The spawning frequency and capacity of the crossbred P were significantly more productive than those of the inbred. In both populations, the majority of P had the greatest egg numbers in the 8th to 14th broods. The hatching percentages of eggs and the survival percentages of nauplii from the 10th brood of the F ₁ populations were significantly higher than those of the 20th and 1st broods. The inbreeding in F ₁ had no effect on hatching and survival percentages, sex ratios of males to females, average weight, body length and specific growth percentages. Our findings suggest that the inbred populations in P and F ₁ were able to yield eggs similar to the crossbred populations, with similar growth, hatching and survival percentages.     

A New Species of Streptocephalus Fairy Shrimp (Crustacea,Anostraca) with Tetrahedral Cysts from Central Thailand

A new species of fairy shrimp, Streptocephalus siamensis n. sp., is described from five temporary pools in Suphan Buri and Kanchana Buri Provinces, central Thailand. It sometimes co‐occurs with its congener, S. sirindhornae . This new species belongs to the subgenus Parastreptocephalus which is defined by bearing tetrahedral cysts. This is the third anostracan species reported from Thailand. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)