The early life stages of cephalopods ‐ octopods, squids, sepiolids and ommastrephids ‐, are uncommon in zooplankton samples and little is known about their life strategies. Accordingly, cephalopod paralarvae were examined in the upwelling ecosystem of the Ría de Vigo (NW Spain) at night from 2008 to 2010. Multivariate analyses and generalized linear models (GLMs) were used to explore relationships between cephalopod paralarvae and the zooplankton communities that they inhabited in 2008. In addition, the foraging strategy and prey preferences of Octopus vulgaris paralarvae within these communities were determined. Multivariate and GLM results showed a strong association of cephalopod paralarvae with coastal and frontal zooplankton communities. Octopus paralarvae were shown to be specialist predators with a strong preference for decapod zoeae in each of the communities examined. Using the three years of sampling, GLM analyses of paralarval spatio‐temporal variations in relation with the upwelling strength showed a positive relationship with upwelling intensity for O. vulgaris and sepiolids, as well as contrasting temporal, horizontal and vertical distributions for the different paralarvae analysed. Under strong upwelling events, Octopus paralarvae were more abundant in surface waters, whereas the abundance of loliginids and sepiolids was higher in the water column. This vertical behaviour in conjunction with the physical conditions of the Western Iberian Upwelling ecosystem suggests the coexistence of two different life strategies: a coastal strategy displayed by loliginid and sepiolid paralarvae that are retained over the shelf, and an oceanic strategy displayed by O. vulgaris paralarvae that are dispersed far from the shelf.

The short-term, meso-scale variability of the mesozooplankton community present in the coastal upwelling system of the Ría de Vigo (NW Spain) has been analysed. Three well-defined communities were identified: coastal, frontal and oceanic, according to their holoplankton-meroplankton ratio, richness, and total abundance. These communities changed from summer to autumn due to a shift from downwelling to upwelling-favourable conditions coupled with taxa dependent changes in life strategies. Relationships between the resemblance matrix of mesozooplankton and the resemblance matrices of meteorologic, hydrographic and community-derived biotic variables were determined with distance-based linear models (DistLM, 18 variables), showing an increasing amount of explained variability of 6%, 16.1% and 54.5%, respectively. A simplified model revealed that the variability found in the resemblance matrix of mesozooplankton was mainly described by the holoplankton-meroplankton ratio, the total abundance, the influence of lunar cycles, the upwelling index and the richness; altogether accounting for 64% of the total variability. The largest variability of the mesozooplankton resemblance matrix (39.6%) is accounted by the holoplanktonmeroplankton ratio, a simple index that describes appropriately the coastal-ocean gradient. The communities described herein kept their integrity in the studied upwelling and downwelling episodes in spite of the highly advective environment off the Ría de Vigo, presumably due to behavioural changes in the vertical position of the zooplankton.

Cystacanths of the acanthocephalan Bolbosoma balaenae (Gmelin, 1790) were found encapsulated in the cephalothorax of the euphausiid Nyctiphanes couchii (Bell, 1853) from temperate waters in the NE Atlantic Ocean. Euphausiids were caught in locations outside the Ría de Vigo in Galicia, NW Spain, and prevalence of infection was up to 0.1%. The parasite was identified by morphological characters. Cystacanths were 8.09 ± 2.25 mm total length (mean ± SD) and had proboscises that consisted of 22 to 24 longitudinal rows of hooks, each of which had 8 or 9 hooks per row including 2 or 3 rootless ones in the proboscis base and 1 field of small hooks in the prebulbar part. Phylogenetic analyses of 18S rDNA and cytocrome c oxidase subunit I revealed a close relationship with other taxa of the family Polymorphidae (Meyer, 1931). The results extend northwards ot the known distribution of B. balaenae. Taxonomic affiliation of parasites and trophic ecology in the sampling area suggest that N. couchii is the intermediate host for B. balenae, and we suggest that the whales Balaenoptera physalus (Linnaeus, 1758) and B. acutorostrata (Lacepède, 1804) are its definitive hosts. This life cycle is probably completed with or without paratenic hosts.KEY WORDS: Acanthocephala · Cystacanths · Bolbosoma balaenae · Zooplankton · Nyctiphanes couchii · NE Atlantic Resale or republication not permitted without written consent of the publisherDis Aquat Org 99: [37][38][39][40][41][42][43][44][45][46][47] 2012 part of the diet of other vertebrates that serve as definitive hosts for a number of parasites. In addition, euphausiids are also a sizeable ingredient of the diet of some marine mammals (Raga et al. 2009). Despite the fact that parasites have great ecological importance, their recruitment (especially for acanthocephalans) in the lower levels of the food web and the role that they play is poorly understood.Adult polymorphid acanthocephalans are intestinal parasites of marine mammals, fish-eating birds and waterfowl. Bolbosoma (Porta, 1908) and Corynosoma (Lühe, 1904) are two of the main genera of intestinal parasites that infect marine mammals (Aznar et al. 2006). The life cycle of Bolbosoma species is thought to involve pelagic marine zooplankton, especially pelagic euphausiids and copepods, as an intermediate host (Hoberg et al. 1993) and different species of fish as paratenic (transport) hosts (Raga et al. 2009). The juvenile forms of acanthocephalans are cystacanths, which are morphologically similar to the mature worms but differ from them in the size of the trunk and the degree of development of the sexual organs (Zdzitowiecki 1991, Hoberg et al. 1993. Moreover, these juvenile forms are widely considered to be the infective stage for definitive hosts. These cystacanths appear contracted with an introverted proboscis and neck inside cysts of the intermediate and paratenic hosts. The genus Bolbosoma, established for Acanthocephala from whales, contains 15 species (Amin 1985) and has a worldwide distribution (Measure...

A new small probable Oligocene dolphin from Ecuador represents a new genus and species, Urkudelphis chawpipacha. The new taxon is known from a single juvenile skull and earbones; it differs from other archaic dolphins in features including widely exposed frontals at the vertex, a dorsally wide open vomer at the mesorostral groove, and a strongly projected and pointed lateral tuberosity of the periotic. Phylogenetic analysis places it toward the base of the largely-extinct clade Platanistoidea. The fossil is one of a few records of tropical fossil dolphins.

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