José Luis Villalobos

Dead Shrimp Blues: A Global Assessment of Extinction Risk in Freshwater Shrimps (Crustacea: Decapoda: Caridea)

We present the first global assessment of extinction risk for a major group of freshwater invertebrates, caridean shrimps. The risk of extinction for all 763 species was assessed using the IUCN Red List criteria that include geographic ranges, habitats, ecology and past and present threats. The Indo-Malayan region holds over half of global species diversity, with a peak in Indo-China and southern China. Shrimps primarily inhabit flowing water; however, a significant subterranean component is present, which is more threatened than the surface fauna. Two species are extinct with a further 10 possibly extinct, and almost one third of species are either threatened or Near Threatened (NT). Threats to freshwater shrimps include agricultural and urban pollution impact over two-thirds of threatened and NT species. Invasive species and climate change have the greatest overall impact of all threats (based on combined timing, scope and severity of threats).

NEW SPECIES OF THE GENUS TYPHLATYA (DECAPODA: ATYIDAE) FROM ANCHIALINE CAVES IN MEXICO, THE BAHAMAS, AND HONDURAS

Abstract Three new species of the genus Typhlatya from anchialine caves in Mexico (T. dzilamensis), the Bahamas (T. kakuki), and Honduras (T. utilaensis) are described. Typhlatya dzilamensis is the fourth species to be described from the Yucatan Peninsula, Mexico, and is morphologically similar to T. mitchelli. Typhlatya kakuki is the first species of the genus to be described from the Bahamas archipelago. Its morphology departs from the patterns showed by the Cuban species, which are the closest geographically. Typhlatya utilaensis is the first species described from Central America, and is found in Utila, one of the Honduras Bay Islands. Morphologically, T. utilaensis is related to T. monae from Mona Island, Puerto Rico, and Barbuda. A revised diagnosis of the genus and a key for the 17 known species are provided.

Results of the global conservation assessment of the freshwater crabs (Brachyura, Pseudothelphusidae and Trichodactylidae): The Neotropical region, with an update on diversity

Abstract 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.

Macromaxillocarididae, a new family of stenopodidean shrimp from an anchialine cave in the Bahamas, with the description of Macromaxillocaris bahamaensis, n. gen., n. sp.

Abstract A new family of stenopodidean shrimp, Macromaxillocarididae, is described from an anchialine cave in Great Guana Cay, Exuma Cays, Bahamas. Macromaxillocaris bahamaensis new genus, new species, is the sole representative of the family. The new taxon clearly belongs to the infraorder Stenopodidea. However, the presence of a massive third maxilliped, pereiopods that increase in length posteriorly, an epistome with two fang-like projections, and a reduced branchial formula distinguish the new family from the rest of the taxa in the infraorder. Moreover, a bifid palp of the first maxilla and an unsegmented palp of the first maxilliped, which are characters not present in the other two known families in the infraorder, support the separate status of the new family. Diagnostic characters of both, the Stenopodidae and Spongicolidae, are found in M. bahamaensis also, being the new taxon morphologically more similar to the Stenopodidae. Diagnoses for the infraorder and the three families, and a key to the families are presented.

NAUSHONIA MANNINGI, NEW SPECIES (DECAPODA: THALASSINIDEA: LAOMEDIIDAE), FROM ACKLINS ISLAND, BAHAMAS

A new species of the rare laomediid genus Naushonia, N. manningi, is described from a cave in Acklins Island, Bahamas. Naushonia manningi represents the seventh species of the genus and the first one to come from a cave. A key to the species of Naushonia is presented.

New Species of Troglobitic Shrimps From Mexico, With the Description of Troglomexicanus, New Genus (Decapoda: Palaemonidae)

A new genus of cavernicolous fresh-water palaemonid shrimp, Troglomexicanus, and two new species, 7: tarnaulipasensis and 7: huastecae, are described from El Abra limestone caves in the states of San Luis Potosi and Tamaulipas, northeastern Mexico. Troglomexicanus includes 7: perezfarfantar, formerly in the genus Troglocubanus. distributed also in El Abra limestone caves. The following characters shared by the 3 species support the creation of the new genus: rostrum without dorsal or ventral teeth, maxilla with single-lobed endite, bilobed epipodite of first maxilliped, second maxilliped without podobranch, and absence of antennal, hepatic, or branchiostegal spines of carapace. The maxilla with single-lobed endite and a bilobed epipodite of first maxilliped are two characters not shared with any other genus in the subfamily Palaemoninae.

Two New Species of Freshwater Crabs of the Genus Tehuana (Brachyura: Pseudothelphusidae) from Southern Mexico

Abstract Two new species of freshwater crabs of the genus Tehuana from the states of Tabasco and Oaxaca, Mexico, are described, and a new diagnosis for the genus is presented. Tehuana chontalpaensis, new species, was collected in a mountain river in southwest Tabasco at 900 m above sea level; it is distinguished by a first gonopod with an elongated mesial process and a large laminar lateral process with a strong lateral spine. Tehuana jacatepecensis, new species, was collected in the Jacatepec river, in central Oaxaca; it differs from other species in the genus by the first gonopod, which has a reduced, spoon-like lateral process and an ax–shaped mesial process that projects beyond the marginal process.

ABBREVIATED LARVAL DEVELOPMENT OF MACROBRACHIUM TUXTLAENSE VILLALOBOS & ALVAREZ, 1999, REARED IN THE LABORATORY

[The abbreviated larval development of the freshwater prawn, Macrobrachium tuxtlaense is described. The first stage of M. tuxtlaense is similar to those of other Mexican and South American species of Macrobrachium such as M. vicconi, M. reyesi, and M. nattereri, sharing uniramous pereiopods, biramous pleopods, and a rounded telson. Newly hatched M. tuxtlaense undergo 5 moults before reaching the juvenile stage. Abbreviated development has allowed M. tuxtlaense to get established in Lake Catemaco, Veracruz, Mexico, where no other of the common coastal plain species of Macrobrachium occur. Se describe el desarrollo larval abreviado del langostino Macrobrachium tuxtlaense. La primera etapa larval de M. tuxtlaense es similar a aquellas de otras especies mexicanas y sudamericanas de Macrobrachium como: M. vicconi, M. reyesi y M. nattereri, con quien comparte pereiopodos unirrameos, pleopodos birrameos y un telson redondeado. Los M. tuxtlaense recien eclosionados pasan por 5 mudas antes de alcanzar la etapa juvenil. El desarrollo abreviado le ha permitido a M. tuxtlaense establecerse en el Lago de Catemaco, Veracruz, Mexico, en donde no se encuentra ninguna otra de las especies de Macrobrachium que son comunes en la planicie costera., The abbreviated larval development of the freshwater prawn, Macrobrachium tuxtlaense is described. The first stage of M. tuxtlaense is similar to those of other Mexican and South American species of Macrobrachium such as M. vicconi, M. reyesi, and M. nattereri, sharing uniramous pereiopods, biramous pleopods, and a rounded telson. Newly hatched M. tuxtlaense undergo 5 moults before reaching the juvenile stage. Abbreviated development has allowed M. tuxtlaense to get established in Lake Catemaco, Veracruz, Mexico, where no other of the common coastal plain species of Macrobrachium occur. Se describe el desarrollo larval abreviado del langostino Macrobrachium tuxtlaense. La primera etapa larval de M. tuxtlaense es similar a aquellas de otras especies mexicanas y sudamericanas de Macrobrachium como: M. vicconi, M. reyesi y M. nattereri, con quien comparte pereiopodos unirrameos, pleopodos birrameos y un telson redondeado. Los M. tuxtlaense recien eclosionados pasan por 5 mudas antes de alcanzar la etapa juvenil. El desarrollo abreviado le ha permitido a M. tuxtlaense establecerse en el Lago de Catemaco, Veracruz, Mexico, en donde no se encuentra ninguna otra de las especies de Macrobrachium que son comunes en la planicie costera.]

Pseudothelphusa zongolicae (Decapoda, Pseudothelphusidae), a new species of freshwater crab from Veracruz, Mexico

A new species of freshwater crab of the family Pseudothelphusidae from Zongolica, Veracruz, Mexico, is described. Only one previous report exists of a pseudothelphusid crab from the Zongolica region in central Veracruz, but that one belongs to a different tribe. The new species is placed in the genus Pseudothelphusa due to the evident torsion of the male gonopod and to the presence of the typical reniform caudo-marginal projection of Pseudothelphusa. The new species can be distinguished from its congeners by a gonopod with a caudo-marginal projection with a single large lobe, which extends proximally to reach beyond the middle of the gonopod’s principal axis, and a conical prominence with terminal pore setae on the distal crest of the caudo-lateral surface. The new species represents the 26th species of the genus with affinities with species from the Pacific versant of Mexico.

Identity of freshwater shrimp populations (Palaemon Weber, 1795) from northern Mexico: genetic variation at local and regional scales

The freshwater genus Palaemon is widely distributed in north-eastern Mexico, where six species have been recognized. Of special interest is the area of the Cuatro Cienegas Valley (CCV) and the Salado and Bravo Rivers basins in central and northern Coahuila, where interconnections, ancient and contemporary, have created a mosaic of populations of species belonging to Palaemon that cannot unequivocally be assigned to one species. We seek to encompass the species determination in a phylogenetic framework by reconstructing phylogenetic relationships of the aforementioned populations and 4 of the species occurring in Mexico. We collected information of three genetic fragments (COI, 12S, and H3) and performed maximum likelihood and Bayesian inference phylogenetic analyses. Also, through the analysis of a partial sequence of the cytochrome oxidase subunit I gene (COI) from individuals coming from 22 populations, we explored phylogeographic patterns from the three basins. Relaxed molecular clock were carried out focused on dating the cladogenesis of all species, while mismatch and Bayesian Skyline Plots analyses were used to test for possible demographic changes in populations from CCV. Gene-separated and concatenated phylogenetic analyses supported the monophyly of the species described from Mexico, but did not show their inclusion in one monophyletic clade, rather depicting a structure congruent with multiple invasions to freshwater. Dating analysis provided long-term temporal framework for cladogenesis. Three different lineages were found in the CCV, confirming the high diversity of this region. One of them is identified with P. sutkussi, and two are possible new species to science. Haplotype analyses provided insight from recent population processes and are congruent with a scenario where despite keeping signatures of past cladogenesis, more recent genetic structure reveals surprisingly higher connectivity between basins associated to the Bravo river system and CCV.