MORPHOMETRIC ANALYZES OF THE SMALL CHELIPEDS OF UCA MARACOANI (LATREILLE, 1802-1803) FROM SOUTHEASTERN BRAZILIAN COAST

MARTINEZ MARILA; COLPO KARINE; NEGREIROS-FRANSOZO MARIA LUCIA

FLORIANÓPOLIS - SC - BRASIL

Congreso; III Congresso Brasileiro sobre Crustáceos; 2004

It's known that fiddler crabs' males have a hypertrophied cheliped. Such appendage has lost its feeding function along the genus evolution. Now-a-days, it is used in the mating behavior and male-male signaling. Females of such crab'species have two small isomorphic claws for feeding on organic. matter content in the sediment The morphometric patte.rn of the small chelipeds for eac.h sex of Uca maracoani were assessed and compared to detect some differences between sexes. Two peoplesampled the crabs for 30 minutes, during low tide period in Paraty, RJ, Brazil. Specimens were sorted concerning sex, and their carapace width (CW) was measured using a caliper (0.01 mm). The propodus length (PU, height (PH), and width of distal portion (PWDP) of the small cheliped of males and the right one. of females were measured under stereomicroscope prOVided with image analysis system. The alometric technique (Y=aXb) was used to evaluate the claws morphometry. Afterthat the equations were log-transformed and compared by covariance analyses. The ON vs PH relationship showed that females (PH=0.316ONO.91, r2=0.88) have the small claw more robust than males (PH=0.167ONO.90, r2=0.85) (ANCOVA, p<0.05). This sexual difference in the cheliped dimensions was also observed in the PL vs PH relationship, females presented the equation PL=0.798PHO.85 (r2=0.85), and males PL=0.358PHO.91 (r2=0.92). The distal portion of the small cheliped scrapes the sediment and the covariance analysis of the PH vs PvVDP relationship showed that males had the tip of the claws larger (PvVDP=0.621PHO.88, r2=0.72) than females (PWDP=0.242PHO.99, r'=0.79). TIlese results evidence that males improved the size of their small chelipeds compensating the alteration of the opposite claw.