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ABSTRACTAeglais a genus of freshwater anomuran Crustacea known for having epimorphic postembryonic development. The newly-hatched juveniles’ morphology have been described for only 11 of the 93 known species. These descriptions are important tools for identifying juveniles and useful characteristics for phylogenetic analyses. This study aims to describe and illustrate the external morphology of the first juvenile stage of Aegla lata. Ovigerous females were collected, fed, and monitored periodically in the laboratory until the eggs hatched. The newly-hatched juveniles were fixed in an alcohol series and preserved in a 70% alcohol and glycerine solution (2:1 ratio) for subsequent dissection and analysis under light microscopy. The appendages were illustrated using a camera lucida and then described. Scanning electron microscopy was used to analyse some specimens, allowing the detailed observation of the setal morphology, some cephalothoracic appendages, and lineae aeglicae. Pappose setae were also observed in the protopod and dactylus of cheliped. The newly-hatched juvenile of A. latahas a set of the following characteristics: basal segment of antennule with serrate setae; distal segment of antennule with pappose setae; merus of second maxilliped with simple setae; and merus of third maxilliped without simple setae.

ABSTRACTAegla castro, is an endemic anomuran crab from Brazil found in headwater streams of the Atlantic Forest on the Paranapanema River basin. This study aims to evaluate the gonadal maturity of A. castrobased on macroscopic and microscopic analyses. Crabs were collected in Mauá da Serra (23º57’ S; 51º06ʹ W), Paraná, Brazil in the winter and spring of 2015, and summer, autumn, and spring of 2016. Individuals had their gonads analysed and categorized into stages of development. Stage1, ovaries are macroscopically undetectable through abdominal transparency, while ovaries of stages 2 and 3 could be detected through abdominal transparency and have characteristic colour and length in relation to the abdominal somites. Ovaries have pre-vitellogenic and vitellogenic oocytes in all stages of development, with germ cells and structural epithelium characteristic of these gonadal maturation phases. Spermatogenesis in males begins in spring, with the production of spermatozoa in autumn and spermiation in winter. Aegla castrohas seasonal reproduction. The macroscopic stages of gonadal development correspond to the histological gonadal maturation, indicating that the macroscopic observation of the gonads of live animals is feasible in studies of the reproductive cycle of aeglids.

AbstractSpecimens of Aegla castroSchmitt, 1942 were monthly sampled from June 2012 to May 2013 from Couro stream (23°57′15″S 51°06′00″W), located in the Upper Paraná river region, southern Brazil. Population structure, morphometric and functional maturity were analyzed. Allometric growth analysis on chela dimension versus carapace length (CL) was employed to recognize juveniles and adult individuals. Two sequential groups of adult males (morphotypes I and II) were recognized according to the state of development of the pair of claws. The CL where 50% of the population of individuals are adults (CL50) was used to estimate the size at the onset of morphometric maturity. Males attain morphometric maturity at same size class of females (8.0–9.0 mm CL). Males and females are heterochelous and they often show the left chela more developed. The reproductive period was extended from June to September 2012 and April to May 2013 (six months) with record of 22 ovigerous females. The recruitment occurred in the months following the reproductive period, with higher records in October and December 2012. All the information gathered here should be useful to better understand the biology of the species studied.

The reproductive capacity of the swimming crab Callinectes danaeSmith, 1869 was assessed based on the reproductive investment (RI) of ovigerous females and the gonadosomatic index (GI) of non-ovigerous adult females. Crabs were collected in June 2009 with a shrimp fishing boat at Ubatuba (23° 26′S 45° 02′W) São Paulo, Brazil. Overall, 191 adult females were analyzed, of which 108 were ovigerous and 83 non-ovigerous. The size of ovigerous females ranged from 54.5 to 79.8 mm carapace width (CW) and non-ovigerous females ranged from 56.0 to 80.9 mm CW. RI values did not differ among the size classes (ANOVA, p > 0.05), with an overall mean of 15.8%. The same occurred with the Gonadossomatic index for non-ovigerous females, for which the mean value was 11.7%. The regression between the dry weight of the egg mass and the dry weight of the crab (Student’s t, p = 0.25; ttab = 1.66; tcal = 0.66) indicated an isometric relationship for the variables analyzed. The simultaneous occurrence of gonadal maturation and embryonic development in ovigerous females suggests that these crabs may spawn at least twice in the same breeding season and reveals the need for evaluation of the allocation of energy in subsequent spawns.

The population biology of Nematopalaemon schmitti in the Ubatuba region on the northern coast of the state of Sao Paulo was characterized through analyses of the length-frequency distribution, sex ratio, reproductive period, and juvenile recruitment. The specimens were caught monthly from January 1998 to December 1999, from a shrimp boat equipped with double-rig trawl nets. A total of 1073 specimens were analyzed, and the sex and carapace length (0.1 mm) of each individual were noted. The analyzed specimens consisted of 152 juveniles, 437 adult males, 296 adult females, and 188 ovigerous females (OFs). The monthly distribution of N. schmitti by size classes revealed a stable population structure, with both juveniles and adults continuously present. This population showed a unimodal distribution; however, bimodality was identified in June 1998 and 1999 for males, and June 1998 and July 1998 and 1999 for females, probably related to recruitment pulses of juveniles. Sexual dimorphism was indicated by the presence of females in the larger size classes, probably because of their growth rate. The proportion between males and females differed from 1 : 1 in certain size classes and seasons of the year (χ2, p < 0.05); in some situations, the females were more abundant than the males, or vice versa. No significant relationship was detected between the seasonal mean temperatures of the bottom water and the percentages of OFs and young, or for the relationship between these two groups (Spearman, p > 0.05). The continuous presence of OFs and young in the population suggests a pattern of continuous reproduction for N. schmitti in the Ubatuba region.

The reproductive biology of Persephona mediterranea was investigated in relation to the following aspects: population structure, size at the onset of sexual maturity, sexual size dimorphism, and reproductive period. A total of 1,283 specimens were obtained (565 males, 120 non-ovigerous females and 598 ovigerous females). CW50 values were 22.8 and 22.3 mm CW for males and females, respectively, and the mean size of males was significantly larger than that of females. Persephona mediterranea shows continuous reproduction. However, there is a reduction in the proportion of ovigerous females and males with gonads in advanced developmental stage during the autumn and beginning of the winter. There was no significant correlation between the reproductive activity and variation in abiotic factors. Of the total captured specimens, 98.99% were sexually mature, which may indicate a differential spatial distribution among the distinct age groups, and sampling sites are probably areas occupied by adult individuals of this population.