Offspring production in three freshwater crab species (Brachyura: Pseudothelphusidae) from the Amazon region and Central America

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

Abbreviation of larval development and extension of brood care as key features of the evolution of freshwater Decapoda

“…Freshwater crabs can be subdivided into primary freshwater crabs consisting of pure freshwater families and secondary freshwater crabs consisting of members of primarily marine brachyuran families (Yeo et al , ; De Grave et al , ; Klaus, Yeo & Ahyong, ). Egg numbers are in the tens to the lower thousands in primary freshwater crabs and directly developing secondary freshwater crabs but can amount to one million in large specimens of amphidromous secondary freshwater crabs (Veilleux & de Lafontaine, ; Wehrtmann et al , ).…”

“…However, there are reports on extended brood care in representatives of all of the five primary freshwater crab families (Table ). Examples are the potamonautid Liberonautes latidactylus (De Man) , the potamonid Candidiopotamon rathbunae (De Man), the pseudothelphusid Kingsleya ytupora Magalhaes, the gecarcinucid Parathelphusa maculata De Man and the trichodactylid Sylviocarcinus pictus (Milne Edwards) (Cumberlidge, ; Liu & Li, ; Souza da Silva, ; Wehrtmann et al , ; Rademacher & Mengedoht, ).…”

“…A). Carriage of the juveniles can encompass more than one juvenile stage as shown for Liberonautes latidactylus , Potamonautes lirrangensis (Rathbun) and Kingsleya ytupora (Cumberlidge, ; Wehrtmann et al , ; Rademacher & Mengedoht, ). The brooded juveniles cling to the pleopods and other maternal structures with their well‐developed chelae (Pace et al , ).…”

The conservation status of decapod crustaceans in the Western Ghats of India: an exceptional region of freshwater biodiversity

“…Conservation of freshwater crabs is a challenge as many species are point endemics (restricted in distribution to a single location or site) owing to their generally restricted dispersal abilities and stenotopic habits (Yeo et al, 2008). Freshwater crabs also have a relatively low fecundity, generally producing an average of around 100 to 300 eggs (Corey and Reid, 1991), which are then incubated by the females from spawning to hatching (Wehrtmann et al, 2010).…”

Description of the first juvenile stage of Dilocarcinus septemdentatus (Herbst, 1783) (Crustacea, Decapoda, Trichodactylidae)

“…Juvenile development has only been described for three freshwater crabs: the trichodactylids Trichodactylus sp. by Müller (1892) and D. pagei by Vieira et al (2013), and the pseudothelphusid Kingsleya ytupora Magalhães, 1986by Wehrtmann et al (2010. However, the latter authors described only the carapace of the first and second juvenile stages.…”