Reproductive system and size maturity of the paddle crab Ovalipes trimaculatus (Brachyura: Portunidae) along the Argentine coast

Ovalipes trimaculatus (de Haan, 1833) is a commercial species captured in the Mar del Plata coast, Argentina. However, no studies were conducted in order to study its population features neither its reproductive biology. The morphometric and physiological maturity of both sexes, the histology of the female seminal receptacle and ovary, and the ultrastructure of the male gonopods were studied in the present paper. In females, morphometric maturity (44.6 mm of carapace width, CW) was acquired prior to physiological maturity (54.6 mm CW). By contrast, in males, physiological maturity (46.6 mm CW) was acquired prior to morphometric maturity (52.3 mm CW). The ovary is connected to the dorsal part of the seminal receptacle. Neither Spermatophores, nor sperm packets were found inside the seminal receptacle; instead free spermatozoids were observed indicating that sperm from different males is probably mixed favoring sperm competition. The ultrastructure of the male gonopods was similar to the described for other Brachyura. Different types of setae and the presence of internal rosette glands were described and probable functions were suggested.