Biological data on Triops cancriformis mauritanicus (Ghigi, 1921) and Cyzicus grubei (Simon, 1886) - Crustacea, branchiopoda - In SW Portugal temporary ponds

Abstract

The lack of information about Notostraca and Spinicaudata in general, and particularly about these taxa in Portugal, can be due to the fact that they are typical of temporary ponds. As most of the species only occur in this kind of habitats, which are highly vulnerable to human action, the study of these systems is of great importance in order to define strategies for their conservation. In April 1996, Triops cancriformis mauritanicus - Branchiopoda, Notostraca - was found in six lagoons from the Vila do Bispo area and in two of those was also found Cyzicus grubei (Simon) - Branchiopoda, Spinicaudata - a species considered endemic to the Iberian Peninsula. In spite of being previously cited as part of the Portuguese fauna (in 1944 and 1951) they were only recently reported in Southwest Portugal (Machado et al., 1999) and there are no other recent records in Portugal. The dimensions of T. c. mauritanicus (maximum standard length = 68.3 mm) are well within those referenced for the Iberian Peninsula, but the maximum valve length of C. grubei (15.1 mm) is about 25% higher than that reported for this species. The morphometric relation studied for T. c. mauritanicus (standard length / carapace length) show sexual dimorphism, while that studied for C. grubei (valve height / valve length) show no difference between sexes. For both species, modal analysis of length frequency distributions suggests the presence of only one cohort. Concerning the sex ratio and although there seems to be a 1:1 ratio for both T. c. mauritanicus and C. grubei, we have found that this ratio is variable among samples. © Asociación Española de Limnología.