Alternation of the female form in Cambaridae (Decapoda: Astacidea) and the designation of a neotype for Procambarus clarkii (Girard, 1852) (Cambaridae: Decapoda)

The alternation of the female form is examined in eleven species of Cambaridae: Cambarus angularis, C. bartonii (), Faxonius virilis (), Procambarus alleni (), P. clarkii (), P. fallax (), P. pallidus (), Cambarellus lesliei, C. patzcuarensis, C. schmitti, and C. shufeldtii (). All species show form-alternation in their annulus ventralis, that of Form I showing a cornified sinus and inflated fossa, but the Form-II females show a un-cornificed sinus and deflated fossa. Morphology of the Form-II annulus ventralis is similar to that of a juvenile. A wider abdomen in Form-I females occurred in five species (C. angularis, C. virilis, C. lesliei, C. schmitti, and C. shufeldtii), and inflation of the palm of the cheliped in Form-I females was observed in four (C. angularis, C. bartonii, F. virilis, and P. clarkii). The range of morphometric female-form alternation demonstrates four patterns: 1) wider abdomen and inflated chela (C. angularis, and C. bartonii), 2) wider abdomen and no chela inflation (C. lesliei, C. schmitti, and C. shufeldtii), 3) no wide abdomen and inflated chela (F. virilis and P. clarkii), 4) no wider abdomen and no chela inflation (P. alleni, P. pallidus, and P. fallax,). A neotype of P. clarkii is also designated and described.