Rapid divergent coevolution of Sinopotamon freshwater crab genitalia facilitates a burst of species diversification

One of the most striking radiations in brachyuran evolution is the considerable morphological diversification of the external reproductive structures of primary freshwater crabs:the male first gonopod(G1)and the female vulva(FV).However,the lack of quantitative studies,especially the lack of data on female genitalia,has seriously limited our understanding of genital evolution in these lineages.Here we examined 69 species of the large Chinese potamid freshwater crab genus Sinopotamon Bott,1967(more than 80%of the described species).We used a landmark-based geometric morphometric approach to analyze variation in the shape of the G1 and FV,and to compare the relative degree of variability of the genitalia with non-reproductive structures(the third maxillipeds).We found rapid divergent evolution of the genitalia among species of Sinopotamon when compared to non-reproductive traits.In addition,the reconstruction of ancestral groundplans,together with plotting analyses,indicated that the FV show the most rapid divergence,and that changes in FV traits correlate with changes in G1 traits.Here we provide new evidence for coevolution between the male and female external genitalia of Sinopotamon that has likely contributed to rapid divergent evolution and an associated burst of speciation in this lineage.

Pesticidal Impact on the Protein Metabolism of Freshwater Field Crab, Oziotelphusa Senex Senex(Fabricius)

The total protein increased in the gills and decreased in the muscle of the freshwater field crab Oziotelphusa senex senex at days 1 and 2 on exposure to lethal concentrations and at days 1 and 10 to sublethal concentrations of furadan, endosulfan, chlorpyrifos, and a mixture of these three in a 100:10: 1 ratio. The increase in the gill protein was greater on exposure to the sublethal concentrations than to the lethal concentrations while the decrease in the muscle protein was greater on exposure to the lethal concentrations than to the sublethal concentrations. In the hepatopancreas, the protein content decreased on exposure to the lethal concentrations, but, in contrast, increased on exposure to the sublethal concentrations. These results clearly indicate that changes in the protein content are not only organ-dependent but also concentration-dependent, i.e., lethal versus sublethal. Irrespective of the changes in the total protein, the levels of free amino acids and the activities of protease, alanine and aspartate aminotransferases, and glutamate dehydrogenase increased in all the three organs of the crabs exposed to the lethal and sublethal concentrations, (more in lethal than in sublethal) and increased at a greater rate over time of exposure. Ammonia toxicity, measured by an increase in the hemolymph ammonia and a decrease in the urea, was also observed at the lethal concentrations of all the three pesticides. The ammonia and urea levels increased in the crabs exposed to the sublethal concentrations. Although the effect of each pesticide on the protein metabolism was similar, the degree of toxicity was the lowest on exposure to furadan, intermediate on exposure to endosulfan and chlorpyrifos, and cumulative on exposure to a mixture of the three pesticides