ZOOLOGIA 27 (6): 965–972, December, 2010 doi: 10.1590/S1984-46702010000600019 Offspring production in three freshwater crab species (Brachyura: Pseudothelphusidae) from the Amazon region and Central America Ingo S. Wehrtmann1,5; Célio Magalhães2; Patricio Hernáez1,3,4 & Fernando L. Mantelatto4 1 Unidad de Investigación Pesquera y Acuicultura of the Centro de Investigación en Ciencias del Mar y Limnología, Universidad de Costa Rica. 2060 San José, Costa Rica. E-mail: [email protected] 2 Coordenação de Pesquisas em Biologia Aquática, Instituto Nacional de Pesquisa da Amazônia. Caixa Postal 487, 69011-970 Manaus, AM, Brazil. E-mail: [email protected] 3 Museo del Mar, Universidad Arturo Prat. Casilla 121, Iquique, Chile. E-mail: [email protected] 4 Laboratório de Bioecologia e Sistemática de Crustáceos, Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Programa de Pós-Graduação em Biologia Comparada. Avenida Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil. E-mail: [email protected] 5 Corresponding author. E-mail: [email protected] ABSTRACT. Freshwater crabs are an important component of the fauna of limnic environments, and out of the two true freshwater crab families present in the Neotropics, Pseudothelphusidae is the most diverse. Considering the lack of information regarding reproductive features of neotropical freshwater crabs, we studied, for the first time, the fecundity and the presence of juveniles carried by females of two pseudothelphusids from the Amazon region – Kingsleya latifrons (Randall, 1840) and Kingsleya ytupora Magalhães, 1986 – and one from Central America – Potamocarcinus magnus (Rathbun, 1896). The two Kingsleya species produced relatively few (56-114) and large eggs (1.9-3.7 mm), typical for species with an abbreviated or direct development. Recently produced eggs were substantially larger in K. latifrons (mean 2.83 mm) when compared to those of K. ytupora (mean 1.87 mm); however, at the end of the embryogenesis, mean egg diameter was similar in both species. Therefore, it is assumed that hatchlings in both species should have a similar size. A brief description of attached juveniles of K. ytupora is provided. The number of juveniles varied between 30 (K. ytupora) and 179 (P. magnus); two size groups of juveniles were found, which indicates that the offspring cling to their mother for a prolonged period of time. There was no significant loss of eggs and juveniles; it is assumed that parental care diminishes the loss of their offspring. We compiled the available information of reproductive aspects from freshwater crabs: egg diameter was in the range of 2-3 mm, independent of female size and fecundity, and reported egg number varied between 9 and 417 eggs. KEY WORDS. Brazil; Costa Rica; freshwater crabs; direct development; fecundity; parental care. The Pseudothelphusidae, with over 250 valid species (NG and nine species for Brazil. In spite its high diversity (YEO et al. et al. 2008, YEO et al. 2008), is by far the most diverse of the two 2008), the biological and ecological aspects of these true freshwater crab families from the Neotropics. Their repre- pseudothelphusid freshwater crabs are poorly studied. Except sentatives are distributed from northern Mexico to Central and for a few brief ecological notes (RODRÍGUEZ & MAGALHÃES 2005), South America as far as the southern limits of the Amazon Ba- the majority of the publications on the neotropical families sin, and have been reported also from some of the Caribbean deal with systematics, taxonomy or zoogeography. However, islands (RODRÍGUEZ 1982). Most of the South American species to the best of our knowledge, reproductive features of inhabit mountainous areas along the Andes, but a branch of the neotropical pseudothelphusids are completely unknown. Kingsleyini, represented mainly by the genera Fredius Pretzmann, All seven species currently assigned to Kingsleya have their 1967, Microthelphusa Pretzmann, 1968, and Kingsleya Ortmann, distribution associated to the uplands of the Guyana and the 1897 extend to the Guyana Shield and Amazon Basin (RODRÍGUEZ Central Brazilian Shields (MAGALHÃES & TÜRKAY 2008). The spe- 1982). cies are usually known only from their type material and even- RODRÍGUEZ & MAGALHÃES (2005) summarized the available tually from a few additional specimens. Exceptions are Kingsleya information on the Pseudothelphusidae and, for Central latifrons (Randall, 1840) and Kingsleya ytupora Magalhães, 1986 America, indicated the presence of 13 genera including 43 spe- for which some scattered observations of females with eggs cies. Similarly, MAGALHÃES (2003a) provided a list of five genera and newly-hatched juveniles have been mentioned by MAGA- © 2010 Sociedade Brasileira de Zoologia | www.sbzoologia.org.br | All rights reserved. 966 I. S. Wehrtmann et al. LHÃES (1986, 2003b). These species are typically found in fast- 1898). However, no females carrying eggs or juveniles were en- flowing habitats such as rapids and waterfalls, occurring among countered. The taxonomic identification of the material used fissures, or under submerged rocks in shallow waters or occa- for the present study was verified by one of us (CM). sionally out of the water, but always in the close vicinity of the The carapace width (CW: distance across the carapace at water source (MAGALHÃES 1986, 2003b). No information on the its widest point) and carapace length (CL: distance along the reproductive cycle for these species is available, except for the midline, from the frontal to the posterior margin) were mea- observations from MAGALHÃES (1986) who indicated that females sured for all females using a Vernier caliper (to nearest 0.05 of K. latifrons carrying eggs or young were captured in July and mm). The same measurements (using a stereomicroscope, to September (Rio Uatumã) and in October (Rio Trombetas) in nearest 0.01 mm) were obtained from the juveniles (N = 10 per the northern tributaries of the Amazon River. For K. ytupora, female) attached to the females. Regarding ovigerous females, egg-bearing females were also reported in October among ma- the entire egg mass was detached and counted. Subsequently, terial collected in the Rio Xingu (MAGALHÃES 2003b). The em- 20 eggs were arbitrarily separated from each female and mea- bryonic or postembryonic development has not been described sured the width and length of each egg under a microscope for any of the Kingsleya species, and the same is true for the equipped with a calibrated ocular micrometer. These data were species of Potamocarcinus H. Milne Edwards, 1853 from Cen- used to calculate egg volume (EV) according to the formula tral America. proposed by TURNER & LAWRENCE (1979) for oblate spheroids: EV Considering the almost complete lack of information re- = 1/6 (a * b2 * ␲), where ‘a’ represents length, and ‘b’ width. garding the reproductive features of neotropical freshwater The developing embryos were classified in early (Stage I: em- crabs, the present study aimed to offer data about fecundity bryos with uniform yolk) and advanced stages (Stage III: eyes and the presence of juveniles carried by females of two clearly visible), following the criteria proposed by WEHRTMANN pseudothelphusid crab species from the Amazon region (K. (1990). In accordance with similar studies of other brachyuran latifrons, K. ytupora) and one from Central America – crabs (e.g. HINES 1991, REID & COREY 1991, MANTELATTO & FRANSOZO Potamocarcinus magnus (Rathbun, 1896). The results obtained 1997, PINHEIRO & HATTORI 2006), the relation between fecundity are part of a long-term collaborative project on freshwater crabs and female size was described by an allometric model (HUXLEY of Central and South America to provide insights in the repro- 1950; Y = aXb). In order to evaluate the possible mortality dur- ductive strategies of freshwater decapods and will hopefully ing embryogenesis and subsequent early juvenile development, stimulate more studies on the ecology of these poorly known an analysis of covariance (ANCOVA; ZAR 1999) was applied to representatives of the neotropical freshwater fauna. examine the relation between offspring number (embryos and juveniles) and CW. In the case of a significant difference (p < MATERIAL AND METHODS 0.05), the Tukey a posteriori test was used to establish the simi- larity between early developmental stages (ZAR 1999). Differ- Ovigerous females and females carrying juveniles were ences between the average of both egg diameter and egg vol- obtained from the collections of the Instituto Nacional de ume of early (Stage I) and advanced eggs (Stage III) were tested Pesquisas da Amazônia (INPA), Manaus, Brazil and of the Museo using a Student t-test (p < 0.05). de Zoología (UCR-MZ), Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica. These two collections contain the RESULTS largest holdings of Pseudothelphusidae in their respective geo- graphic areas. In the INPA-collection, a total of 38 lots of K. Offspring production latifrons and K. ytupora were checked for the presence of females The only female of P. magnus examined herein measured bearing eggs or juveniles. In some of the lots females with egg/ 85.7 mm CW, and carried 179 juveniles with an average CW of juveniles were not kept separately, but these vials were inspected 5.2 ± 0.16 mm (Tab. I). carefully for eggs/juveniles, which may have detached from the We examined a total of 20 females of K. latifrons: eight females. Therefore, detached eggs/juveniles were taken into con- with eggs, two with attached juveniles, and 10 without eggs or sideration for their count. In the entire collection of the UCR- hatchlings. In the case of K. ytupora, a total of 31 females were MZ, comprised by 218 lots of Pseudothelphusidae, only one fe- examined: eight carried eggs, 13 females with juveniles, and male of P. magnus was found with attached juveniles. Addition- 10 females without eggs or juveniles. A regression analysis of ally, abundant material recently collected by Rólier Lara (Instituto the relationship between number of eggs and crab body size Costarricense de Electricidad, Costa Rica) in the Pacific lowlands showed that fecundity increased with female size of K.