Species of the genus Dormitator, also known as sleepers, are representatives of the amphidromous freshwater fish fauna that inhabit the tropical and subtropical coastal environments of the Americas and Western Africa. Because of the distribution of this genus, it could be hypothesized that the evolutionary patterns in this genus, including a pair of geminate species across the Central American Isthmus, could be explained by vicariance following the break-up of Gondwana. However, the evolutionary history of this group has not been evaluated. We constructed a time-scaled molecular phylogeny of Dormitator using mitochondrial (Cytochrome b) and nuclear (Rhodopsin and β-actin) DNA sequence data to infer and date the cladogenetic events that drove the diversification of the genus and to relate them to the biogeographical history of Central America. Two divergent lineages of Dormitator were recovered: one that included all of the Pacific samples and another that included all of the eastern and western Atlantic samples. In contrast to the Pacific lineage, which showed no phylogeographic structure, the Atlantic lineage was geographically structured into four clades: Cameroon, Gulf of Mexico, West Cuba and Caribbean, showing evidence of potential cryptic species. The separation of the Pacific and Atlantic lineages was estimated to have occurred ~1 million years ago (Mya), whereas the four Atlantic clades showed mean times of divergence between 0.2 and 0.4 Mya. The splitting times of Dormitator between ocean basins are similar to those estimated for other geminate species pairs with shoreline estuarine preferences, which may indicate that the common evolutionary histories of the different clades are the result of isolation events associated with the closure of the Central American Isthmus and the subsequent climatic and oceanographic changes.

Intestines of dead northern fur seals (Callorhinus ursinus) on St. Paul Island (SPI), Alaska were inspected for specific internal parasites (hookworms and acanthocephalans) in July and August, 2007. Pups (n=64) were examined for adult hookworms (Uncinaria lucasi) and four (6.25%) were infected. The number of specimens per infected pup was 1, 2, 2, or 408. Low prevalence was similar to that determined in the last investigation (2001) in dead fur seal pups on SPI by two of the present authors (Lyons and Spraker). Subadult males (SAMS-3-4 years old, n=115) were examined for acanthocephalans and 25 (21.7.0%) were infected. Adult Corynosoma (C. obtuscens, C. strumosum, and C. validum) (n=56) and immature Bolbosoma spp. (n=4) were found. Apparently, this is a new host record for C. obtuscens and C. validum. Notes were made on finding tapeworms. in 114 of the 115 SAMs. Examination of some specimens revealed scolices characteristic of Diphyllobothrium spp.

Los miembros del género Clinostomum, son un grupo de parásitos que en estadio adulto residen en la cavidad bucal de aves ictiófagas, mientras que la fase de larva conocida como metacercaria, se encuentran en forma de quiste de color amarillo en músculo, cavidad oral, ojos, branquias, tejido subcutáneo, gónadas, hígado y otros órganos, en peces de vida silvestre y cultivados distribuidos en todo el mundo. En el presente proyecto de investigación recopilamos información disponible en la base de datos del GenBank de las especies del género Clinostomum de diferentes regiones biogeográficas de América, Europa, Asía y África, con un especial énfasis en la biodiversidad de México y centro América. La base de datos genética se formó con 394 secuencias de las cuales, 269 secuencias fueron obtenidas de 51 localidades de la región neártica y neotropical de México y de dos países de centro América como: Honduras y Costa Rica. Los análisis filogenéticos inferidos con los métodos de máxima verosimilitud e Inferencia bayesiana, reconocieron 8 clados o grupos independientes que corresponde a 6 especies previamente descritas en México, Honduras y Costa Rica como: C. tataxumui, C. heluans, C. cichlidorum, C. arquus, C. caffarae y C. marginatum, más dos especies candidatas Clinostomum spp. (Linaje 1 y Linaje 3). Las 6 especies de Clinostomum distribuidas en México se encuentran asociadas a cinco especies de aves acuáticas de la familia Ardeidae, mientras que las metacercarias presentan un patrón de especificidad con peces de las familias Catostomidae, Cyprinidae, Goodeidae, Cichlidae, Eleotridae, Pimelodidae, Characidae, Profundulidae, y Poeciliidae, que funcionan como el segundo huésped intermediario. Probablemente, estas asociaciones ecológicas fueron claves y fundamentales en la distribución de las especies del género Clinostomum en México y centro América.