The juvenile stages of Parastacus brasiliensis (von Martens, 1869) (Crustacea, Decapoda, Parastacidae)

Abstract

The family Parastacidae consists of the freshwater crustaceans popularly known as crayfishes or crawfishes. Only the genus Parastacus occurs in Brazil, with P. brasiliensis (von Martens, 1869) endemic to the state of Rio Grande do Sul in southern Brazil. Parastacids have direct development, ecloding as juveniles. In laboratory‐reared specimens, juvenile I stage is similar in morphology to the adult, with no setae on most appendages, absence of uropods and presence of a hook on the dactyl of pereiopods 4 and 5. The juvenile II retains juvenile I characteristics but has more setae, which are more varied in morphology. The juvenile III possesses setae as the adults, fully formed uropods and the hooks on pereiopods 4 and 5 are substituted by an apical rectilinear dactylus.

Keywords:

• Juvenile
• morphology
• Parastacidae
• Parastacus brasiliensis
• setae

Acknowledgements

This paper is contribution no. 392 of the Department of Zoology, UFRGS.

Notes

^aSegments of the appendices: bsg, basal segment; bsp, basipodite; c, carpodite; cxp, coxopodite; d, dactylopodite; de, distal endite; dsg, distal segment; end, endopodite; exp, exopodite; exf, external flagellum; fl, flagellum; inf, internal flagellum; i, ischiopodite; m, meropodite; msg, median segment; p, propodite; pt, protopodite; pe, proximal endite.

^bSetae: I, simple setae; II, cuspidate setae; III, conate setae; IV, hamate setae; V, aesthetascs setae; VI, tooth setae; VII, teazel setae; VIII, plumose setae; IX, pappose setae; X, serrate setae; XI, multiserrate setae; XII, plumodenticulate setae.