Relative growth of Acantholobulus schmitti (Rathbun, 1930) (Crustacea, Brachyura, Panopeidae) at Guaratuba Bay, southern Brazil

Abstract

A study on the relative growth of the crab Acantholobulus schmitti (Rathbun, 1930) (Decapoda, Brachyura, Panopeidae) was performed with allometric techniques. The species is associated with lanterns used for oyster farming at Guaratuba Bay, southern Brazil. Crabs were obtained from five lanterns from March through December 2009. The following morphological characteristics were measured: the carapace width (CW), the height and length of the major cheliped propodus (LPH and LPL), the width of the female abdomen at the base of the 4th somite (AW) and the length of the male gonopod (GL). A total of 1,004 individuals of A. schmitti were measured, of which 451 were males, 323 non-ovigerous females and 230 ovigerous females. The CW of the males varied from 1.87 to 11.86 mm, that of non-ovigerous females from 1.44 to 8.77 mm and that of ovigerous females from 4.09 to 11.12 mm. The plot of LPH against CW showed a mean inflection point at 3.67 mm CW for the males. This result indicated that male crabs are juvenile below this value and adult above it. For the females, the corresponding inflection point occurred at 3.36 mm CW in the plot of AW against CW. These results, CW x LPH and CW x AW, highlight the importance of chelae enlargement at the onset of maturation in males. Similarly, the widening of the abdomen in females is required to accommodate egg clutches during the reproductive period. Heterochely was recorded in both sexes. Right-handed crabs were more frequent than left-handed ones, with percentages of 75.8% in males and 82.7% in females. The population of A. schmitti from Guaratuba Bay becomes sexually mature at an earlier age than A. schmitti from the coast of São Paulo state. The lanterns used in oyster farming furnish a safe habitat in which these crabs can spend their entire benthic life.

Relative growth, morphological sexual maturity, heterochely, and handedness in Panopeus occidentalis (Brachyura, Panopeidae)

“…As a result, injury to or structure. This was observed in the present study, and in other studies on Trichodactylus fluviatilis Latreille, 1828 (Lima et al 2013), A. schmitti (Frigotto et al 2013), and P. americanus (Carvalho-Batista et al 2015).…”

Method of capture and population structure of Aegla georginae Santos and Jara, 2013 (Decapoda: Anomura: Aeglidae) in a tributary of the Ibicuí River in southern Brazil

“…The absence of females in the late spring and summer indicates that reproduction probably does not occur in the warmer months of the year. Local climatic conditions can influence life cycle of crustaceans (Frigotto et al, 2013). Bueno and Shimizu (2008) performed an extensive revision of the factors responsible for the interspecific variation on the reproductive period of aeglids and suggest that the reproductive period tends to be concentrated in the colder months of the year at lower latitudes, as is the case in the present study.…”

Relative growth and size at onset of sexual maturity of the brown crab, Cancer pagurus in the Isle of Man, Irish Sea

“…Crustacean growth is discontinuous and different body parts of males and females often exhibit different growth rates. This phenomenon is commonly known as "relative growth" or "allometric growth" (Hartnoll 1978;Frigotto et al 2013). In particular, the changes in size of secondary sexual characters (e.g.…”