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This study reports the presence of the nematode Vasorhabdochona cablei in the digestive tract of the white grunt, Haemulopsis leuciscus (syn. Pomadasys leuciscus) collected in the Chamela Lagoon, State of Jalisco, Mexico. This rhabdochonid species is characterized by the absence of longitudinal thickenings or teeth in the anterior end of vestibule, vulva in the anterior part of body and eggs without polar plugs or filaments. Its occurrence in this fish represents a new host record, since V. cablei has only been reported from an estuarine (Gobiomorus maculatus) and marine fish (Gillichthys mirabilis) from neighboring localities in the Pacific coast of Mexico.
The present paper focuses on the evolutionary dynamics of ammonites from sections along the Russian Pacific coast during the midand Late Cretaceous. Changes in ammonite diversity (i.e., disappearance [extinction or emigration], appearance [origination or immigration], and total number of species present) constitute the basis for the identification of the main bio−events. The regional diversity curve reflects all global mass extinctions, faunal turnovers, and radiations. In the case of the Pacific coastal regions, such bio−events (which are comparatively easily recognised and have been described in detail), rather than first or last appearance datums of index species, should be used for global correlation. This is because of the high degree of endemism and provinciality of Cretaceous macrofaunas from the Pacific region in general and of ammonites in particular.
We describe and re−evaluate the systematics of specimens from the Maastrichtian Moreno Formation of California (west− ern USA) as a new species of Saurolophus, the only known genus of hadrosaurid dinosaur widespread in Asia and North America. Recognition of this new species adds substantially to the record of the taxonomic diversity of these animals west of the Rocky Mountains. The new species, Saurolophus morrisi, is diagnosed by the possession of a postorbital having or− namentation in form of wide oblique groove on jugal process. Placement of this new species in Saurolophus considerably expands the distribution of this genus, although this referral is arbitrary since phylogenetic analysis places the new species outside of the clade formed by Saurolophus osborni and Saurolophus angustirostris. However, recognition of a new, en− demic Californian hadrosaurid, especially one so closely related to both Asian and North American species, may have im− plications for future studies of both the internal biogeography of Western North America, and the history of exchange with Asia.
The occurrence of the dracunculoid nematode Philometra chilensis Moravec, Chávez et Oliva, 2011 (Philometridae) infecting the ovary of the red cusk-eel, Genypterus chilensis (Guichenot), off the Pacific coast of northern Chile is reported. A sample of 266 fish specimens (total body length 34–96 cm) revealed the nematode overall prevalence (April 2007) of this parasite to be 18.5% and the mean intensity of infection 17.9 (SD = 30.8). All infected fish were mature females. The present results suggest that infection by the nematode shows seasonality and coincides with specific reproductive stages of the red cusk-eel, a partial spawner, and as a result the infection can affect the reproductive success of the host.
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