Variation in cheliped form in two species of squat lobsters (Decapoda: Anomura) from Chile

LEZCANO AH; PENNA MA ; MARQUEZ FEDERICO; THIEL M

BRAZILIAN JOURNAL OF OCEANOGRAPHY

INST OCEANOGRAFICO

Lugar: São Paulo; Año: 2015 vol. 63 p. 303 - 310

1679-8759

The current study describes the variation in cheliped form of two species of squat lobsters that inhabit the continental margin off Chile: Cervimunida johni and Pleuroncodes monodon. We compared their cheliped form in the context of the reproductive strategy. The general tendency of form variation of both species is almost similar: chelipeds change, in average from longer and narrower pollex with short manus to a relatively shorter and wider pollex with longer manus from small to large individuals, respectively. The degree of cheliped arching was, however, greater in males than in females of similar carapace length. Among males, only C. johni showed fully arched morphology. The allometric trajectories (cheliped shape vs carapace length) were largely aligned with vectors of mean shape difference in both species. Cheliped form variation of C. johni (extended mate-guarding) resembles the cheliped morphology reported for the related species Munida rugosa more than P. monodon (short mate-guarding). Our results are consistent with previous finding and suggest that the cheliped form variation (from straight and slender to a fully arched morphology) is, or has been, subject to sexual selection through male-male competition for mates.