Insular species of Neotropical freshwater crabs (Crustacea: Brachyura) (original) (raw)
Related papers
2008
The Island of São Sebastião is the largest and most populated island on the northern coast of São Paulo, Brazil. Despite its unquestionable importance as a State Park area, now permanently preserved, no scientific information on the freshwater decapod crustaceans living on this island is available. Here, we furnish taxonomical and distributional features of the freshwater crabs, as part of a long-term effort to identify and characterize the biology of decapod crustaceans occurring on the island. The data for the survey were obtained between July 2006 and October 2007, by sampling at 65 different points around the island, from sea level to about 200 m a.s.l., using sieves and traps. The species found were Trichodactylus dentatus, T. fluviatilis and T. petropolitanus. Although mature males and females were collected, ovigerous females were not. The presence of the Trichodactylidae, an exclusively freshwater group, on oceanic islands has great value in studies of biogeographical, ecological, and evolutionary processes in crustaceans, and should be a topic of future studies in order to better enhance knowledge of the relationship between island and continental populations and the mechanisms of colonization in both habitats.
ZooKeys, 2014
The freshwater crabs of the Neotropics comprise 311 species in two families (Pseudothelphusidae and Trichodactylidae) and one or both of these families are found in all of the countries in the Neotropical region (except for Chile and some of the Caribbean islands). Colombia (102 species, 81% endemic) and Mexico (67 species, 95% endemic) are the biodiversity hotspots of freshwater crab species richness and country-level endemism for this region. The results of the IUCN Red List conservation assessments show that 34% of pseudothelphusids and 10% of trichodactylids have an elevated risk of extinction, 29% of pseudothelphusids and 75% of trichodactylids are not at-risk (Least Concern), and although none are actually extinct, 56% of pseudothelphusids and 17% of trichodactylids are too poorly known to assess (Data Deficient). Colombia (14 species), Venezuela (7 species), Mexico (6 species), and Ecuador (5 species) are the countries with the highest number of threatened species of Neotropical freshwater crabs. The majority of threatened species are restricted-range semiterrestrial endemics living in habitats subjected to deforestation, alteration of drainage patterns, and pollution. This underlines the need to prioritize and develop conservation measures before species decline to levels from which they cannot recover. These results represent a baseline that can be used to design strategies to save threatened Neotropical species of freshwater crabs.
Phylogeography of an Island Endemic, the Puerto Rican Freshwater Crab (Epilobocera sinuatifrons)
Journal of Heredity, 2008
The endemic Puerto Rican crab, Epilobocera sinuatifrons (Pseudothelphusidae), has a freshwater-dependant life-history strategy, although the species has some capabilities for terrestrial movement as adults. In contrast to all other freshwater decapods on the island (e.g., caridean shrimp), E. sinuatifrons does not undertake amphidromous migration, and is restricted to purely freshwater habitats and adjacent riparian zones. As Puerto Rico has a dynamic geologic history, we predicted that both the life history of E. sinuatifrons and the geological history of the island would be important determinants of phylogeographic structuring in the species. Using a fragment of the cytochrome c oxidase subunit 1 mtDNA (mitochondrial DNA) gene, we tested for deviations from panmixia among and within rivers draining Puerto Rico and used statistical phylogeography to explore processes that may explain extant patterns of genetic variation in the species. While populations of E. sinuatifrons were significantly differentiated among rivers, they were likely to be recently derived because nested clade analysis (NCA) indicated evolutionarily recent restricted gene flow with isolation by distance (IBD) and contiguous range expansion at various spatial scales. Ongoing drainage rearrangements associated with faulting and land slippage were invoked as processes involved in sporadic gene flow among rivers throughout the Pleistocene. Patterns of genetic differentiation conformed to IBD and population demographic statistics were nonsignificant, indicating that although recently derived, populations from different rivers were in drift-mutation equilibrium. A shallow (0.6 million years ago), paraphyletic split was observed in the haplotype network, which NCA indicated arose via allopatric fragmentation. This split coincides with an area of high relief in central Puerto Rico that may have experienced relatively little drainage rearrangements. Shallow but significant genetic isolation of populations of E. sinuatifrons among Puerto Rican rivers suggests phylogeographic patterns that are intermediate to terrestrial habitat specialists (highly divergent populations) and other freshwater biota, such as amphidromous species and insects with aerial adult dispersal (highly connected populations).
Nauplius, 2020
The study of Colombian freshwater crabs has advanced significantly, but species records are scattered across different museums and research institutions. Assuming that museum collections incorporate valuable information in estimating species diversity, a database was organized on the 94 known species of family Pseudothelphusidae, which includes 568 records from 1853 to 2019 in continental Colombia and Gorgona Island. The natural regions of Colombia (Amazonian, Andean, Caribbean, Orinoquian, Pacific) were further subdivided into 75 natural sub-regions according to habitat types used by freshwater crabs. Sub-regions were (i) ranked in terms of species richness, with respective species reported in each sub-region listed accordingly, and (ii) classified into a scale of five categories on the basis of a geometric biodiversity index combining species richness and Simpson index. Species accumulation curves are presented to estimate the current status of knowledge about the diversity of the Colombian pseudothelphusids. Although the available data are not standardized for an adequate assessment of relative abundance, since they are influenced by sampling efforts and natural sub-regions are of different sizes and characteristics, the present study may be useful in future ecological and biogeographic research, as well as for conservation purposes.
A collection of Majoidea Samouelle, 1819 crabs carried out during the KARUBENTHOS 2012 Expedition to Guadeloupe Island and sorted during an international workshop at Besse-et-Saint-Anastaise in 2013 is reported. A total of 60 species are identified, 30 being new records for Guade-loupe Island. Each species is presented with notes on habitat, geographical distribution and previous records for the Lesser Antilles. A documented list of 42 additional Majoidea species is also proposed for the Lesser Antilles Islands based on a bibliographic research. A total of 102 Majoidea crabs are currently reported from the Lesser Antilles, of which 81 around Guadeloupe Island. RÉSUMÉ Les crabes Majoidea de l'île de la Guadeloupe, avec une liste commentée des espèces des Petites Antilles (Crustacea, Decapoda, Brachyura, Majoidea). Une collection de crabes Majoidea Samouelle, 1819 réalisée durant la mission KARUBENTHOS 2012 à la Guadeloupe et triée pendant un atelier scientifique international à Besse-et-Saint-Anastaise en 2013 est présentée. Au total 60 espèces ont été reconnues dont 30 sont nouvelles pour la Guade-loupe. Chaque espèce est présentée avec des notes sur son habitat, sa distribution géographique et les signalements précédents aux Petites Antilles. En complément, une liste documentée de 42 autres espèces de crabes Majoidea est également proposée à partir d'une recherche bibliographique. Au total, 102 crabes Majoidea sont actuellement connus aux Petites Antilles, dont 81 autour de la Guadeloupe.
Johngarthia planata is an abundant and ecologically important land crab, distributed on East Pacific islands from the Gulf of California to Colombia. However, despite possible dispersal of planktotrophic larvae by sea currents, J. planata is not known from inshore islands and mainland of Central America. In this study, the presence of J. planata on Costa Rican inshore islands is reported for the first time, strongly supporting the significance of coastal currents for the distributional patterns of such species. Despite the proximity of the Costa Rican inshore islands to the mainland coast and larval dispersal by passing coastal currents, J. planata was not found in mainland locations. We suggest that a high diversity of continental land crab predators excludes J. planata from the continental mainland habitat, while the closely related Gecarcinus quadratus may have adaptations to high predation pressure.
Shallow phylogeographic structure of Puerto Rico freshwater crabs
Crustacean Issues, 2011
Freshwater crabs constitute a common faunal component of tropical and subtropical river systems. They have a worldwide occurrence in these warmer regions, being represented by different taxonomic lineages on different continents or even within continents. Due to their mostly direct development and assumed dependency on fresh water, freshwater crabs are considered reliable model organisms to genetically reconstruct the hydrographical history of a region. However, very few studies have been carried out to directly document within-river dispersal or overland dispersal of these crabs. Thus the questions remain, in how far the restriction to river systems is comparable throughout the different taxa of freshwater crabs, and if all of the taxa can be used similarly well to reconstruct the history of watersheds, orogeny, island formation, and continental drift. In the current study, we analyze the phylogeographic structure of Epilobocera sinuatifrons (Decapoda: Brachyura: Pseudothelphusidae), a freshwater crab species endemic to the Caribbean island of Puerto Rico. Results show limited morphometric and genetic (mitochondrial and nuclear DNA) differentiation among metapopulations along a west-east gradient, paralleling the direction of the main mountain chain. The north-south comparison, in turn, does not show any differentiation, suggesting that the crabs must be able to migrate between headwaters of unconnected river systems. These results are compared to recently published ones on phylogeographic structure within species of Sesarma (Decapoda: Brachyura: Sesarmidae) from Jamaican rivers. The Jamaican freshwater crabs are endemic to a much smaller geographic area and show a pronounced genetic-geographical structure with restricted gene flow among many of the studied rivers systems. These results are unexpected, because the colonization of Jamaica occurred much more recently according to geological history and because the Jamaican crabs still have an abbreviated larval development (González-Gordillo et al. 2010) which should favor distribution within a drainage system and possibly among rivers, if able to survive in coastal areas. This comparison gives evidence for different distribution potential in freshwater crabs and cautions about the assumption that these crabs do not migrate between rivers and are thus infallible biogeographic model systems.