Manganese tissue accumulation and tyrosine hydroxylase immunostaining response in the Neotropical freshwater crab, Dilocarcinus pagei, exposed to manganese

The aim of the present study was to determine the size at sexual maturity in the freshwater crab Dilocarcinus pagei Stimpson, 1861, from a population located in Mendonça, state of São Paulo, Brazil. The crabs were sampled monthly (July 2005 to June 2007), at Barra Mansa reservoir. The specimens were captured manually or in sieves passed through the aquatic vegetation. The crabs were captured and separated by sex based on morphology of the pleon and on the number of pleopods. The following dimensions were measured: carapace width (CW); carapace length (CL); propodus length (PL); and abdomen width (AW). The morphological analysis of the gonads was used to identify and categorize individuals according to their stage of development. The morphological maturity was estimated based on the analysis of relative growth based on the allometric equation y = ax b. The gonadal maturity was based on the morphology of the gonads by the method CW50 which indicates the size at which 50% of the individuals in the population showed gonads morphologically mature to reproduction. The biometric relationships that best demonstrated the different patterns of growth for the juvenile and adult stages were CW vs. PL for males and CW vs. AW for females (p<0.001). Based on these relationships, the estimated value to morphological sexual maturity was 21.5 mm (CW) in males and 19.7 mm (CW) in females. The determination of the size at sexual maturity and the adjustment of the data based on the logistic curve (CW50) resulted in a size of 38.2 mm for males and 39.4 mm for females (CW). Based on the data obtained for sexual maturity for D. pagei, we can estimate a minimum size for capture of 40 mm (CW). This minimum size allows at least half of the population to reproduce and retains the juveniles and a portion of the adults in the population.

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Daily Rhythm of Feeding Activity of the Freshwater Crab Dilocarcinus Pagei Pagei in the Rio Pilcomayo National Park, Formosa, Argentina

Modern Approaches to the Study of Crustacea ◽

10.1007/978-1-4615-0761-1_27 ◽

2002 ◽

pp. 171-178 ◽

Cited By ~ 7

Author(s):

Verónica Williner ◽

Pablo A. Collins

Keyword(s):

National Park ◽

Feeding Activity ◽

Daily Rhythm ◽

Freshwater Crab ◽

Dilocarcinus Pagei

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Juvenile development of Dilocarcinus pagei Stimpson, 1861 (Brachyura, Trichodactylidae) reared in the laboratory, with emphasis on setae morphology

Crustaceana ◽

10.1163/15685403-00003247 ◽

2013 ◽

Vol 86 (13-14) ◽

pp. 1644-1663 ◽

Cited By ~ 3

Author(s):

Rony R. R. Vieira ◽

Paulo J. Rieger ◽

Viviane Cichowski ◽

Marcelo A. A. Pinheiro

Keyword(s):

Sexual Dimorphism ◽

Water Hyacinth ◽

Morphological Characters ◽

Juvenile Stage ◽

Freshwater Crab ◽

The Third ◽

Laboratory Conditions ◽

Juvenile Stages ◽

Juvenile Development ◽

Dilocarcinus Pagei

The juvenile development of the freshwater crab Dilocarcinus pagei Stimpson, 1861 was studied under laboratory conditions, focusing on setae morphology. The ovigerous females were collected manually associated with water hyacinth at the Municipal Dam of São José do Rio Preto (São Paulo, Brazil). The specimens were raised in the laboratory under constant aeration, photoperiod (12 : 12 h) and temperature (27 ± 1°C). Twelve juvenile stages were obtained with descriptions of the main morphological characters that allow their identification are presented. Fourteen types of setae were discovered: dentate, denticulate, serrulate, papposerrate, cuspidate, plumose, plumodenticulate, plumoserrulate, simple, pappose, brush, curved, nail and setules. The greatest diversity of setae was found on the mouth appendages, especially the maxillule. The gill ontogeny and sexual dimorphism becomes apparent from the second juvenile stage onwards. At the third juvenile stage, the carapace begins to exhibit a wider shape, becoming similar to that of the adults.

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