Rafael Robles

ON STABILISING THE NAMES OF THE INFRAORDERS OF THALASSINIDEAN SHRIMPS, AXIIDEA DE SAINT LAURENT, 1979 AND GEBIIDEA DE SAINT LAURENT, 1979 (DECAPODA)

The names Gebiidea and Axiidea, erected by de Saint Laurent (1979), have priority over others for the two infraorders of shrimps previously included in Thalassinidea. Importantly, Thalassinidea are not monophyletic and the name should be replaced. Gebiidea and Axiidea, besides having priority and describing two monophyletic taxa, are now in common use (130 citations) and are more stable than alternative schemes proposed by Sakai (2005 and later). The history of the names of higher taxa applied to these groups is reviewed, and all family-group taxa listed.

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.]

NEW RECORD OF CALYPTRAEID HOSTS FOR THE PEA CRAB CALYPTRAEOTHERES GARTHI (FENUCCI, 1975) (DECAPODA, PINNOTHERIDAE) IN ARGENTINA

Calyptraeotheres garthi (Fenucci, 1975) is one of nine species of Pinnotheridae occurring in Argentina and the only species of that genus located in this region. This species can be found from the San Matias Gulf, Argentina to Rio Grande do Sul, Brazil where it lives in symbiotic association with limpets of the family Calyptraeidae. Currently, two species of limpets have been reported as hosts of this species: Crepidula protea (d’Orbigny, 1841) and Crepidula argentina Simone, Pastorino & Penchaszadeh, 2000. We report here four more species of limpets serving as hosts of C. garthi, namely Bostrycapulus odites Collin, 2005, Crepidula cachimilla Cledon, Simone & Penchaszadeh, 2004, Crepidula plana Say, 1822 and Trochita pileus (Lamarck, 1822). Thus, this pinnotherid appears to be, as others members of the family, a generalist symbiotic species since it dwells on almost all the potential limpet species reported for Argentina. However, there are notable differences in prevalence of C. garthi on each host, which suggest that the symbiont might prefer species of Crepidula over the others genera (Trochita and Bostrycapulus). Additionally, there exists an apparent relationship between host size and prevalence (e.g., Crepidula cachimilla, the limpet with the highest prevalence, is clearly larger than the others hosts). Perhaps it is premature to conclude that the size of the host might be of benefit for the symbiont, but it is a hypothesis worthy of being explored.

DNA sequence database as a tool to identify decapod crustaceans on the Sao Paulo coastline

Abstract DNA barcoding has emerged as an efficient tool for taxonomy and other biodiversity fields. The vast and speciose group of decapod crustaceans is not an exception in the current scenario and comparing short DNA fragments has enabled researchers to overcome some taxonomic impediments to help broadening knowledge on the diversity of this group of crustaceans. Brazil is considered as an important area in terms of global marine biodiversity and some regions stand out in terms of decapod fauna, such as the São Paulo coastline. Thus, the aim of this study is to obtain sequences of the mitochondrial markers (COI and 16S) for decapod crustaceans distributed at the São Paulo coastline and to test the accuracy of these markers for species identification from this region by comparing our sequences to those already present in the GenBank database. We sampled along almost the 300 km of the São Paulo coastline from estuaries to offshore islands during the development of a multidisciplinary research project that took place for 5 years. All the species were processed to obtain the DNA sequences. The diversity of the decapod fauna on the São Paulo coastline comprises at least 404 species. We were able to collect 256 of those species and sequence of at least one of the target genes from 221. By testing the accuracy of these two DNA markers as a tool for identification, we were able to check our own identifications, including new records in GenBank, spot potential mistakes in GenBank, and detect potential new species.

Two new species of the genus Lepidophthalmus (Decapoda, Axiidea, Callianassidae) from coastal Pacific waters of Central America.

Two new species of intertidal ghost shrimp are described from coastal Central American habitats of the eastern Pacific Ocean, bringing the total known membership of the genus to 18 species. Lepidophthalmus natesi sp. nov. from Colombia and Nicaragua shares with Lepidophthalmus panamensis sp. nov. from Colombia and Panama the lack of extensive ventral pleomere armor, especially in lacking a median ventral sclerite on the second pleomere. The absence of this plate is also a character of the eastern Pacific species L. rafai Felder & Manning, 1998, but the two new species differ from it in telson shape. Ventral armor including this plate is present in Lepidophthalmus bocourti (A. Milne-Edwards, 1870) and L. eiseni Holmes, 1904 which occur sympatrically with L. natesi sp. nov. in eastern Pacific tropical estuaries. As also known for at least L. bocourti, L. natesi sp. nov. invades and densely colonizes penaeid shrimp aquaculture ponds in regional estuarine settings. Individuals of L. panamensis sp. nov. are of smaller body size but also may be densely concentrated, especially in clayey substrates including those adjacent to intertidal rocks. Despite their similarities in the pleon and shape of the telson, the species can be readily separated by dentition of the cheliped fingers, relative length of the minor chela fingers, the second pleopod appendix of mature males, and egg size. The large eggs of L. panamensis sp. nov. suggest extremely abbreviated development. Characteristic coloration is described for both new species.