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Background. The blackspotted smooth-hound, Mustelus punctulatus Risso, 1826, has been regularly caught in the northern Adriatic Sea, although a decreasing trend in its catches was observed off the coast of Slovenia within the last decade. The knowledge of feeding behaviour of elasmobranch fish species, through understanding of the local food web structure, contributes to better and more efficient fish stock assessment and ecosystem modelling. This study is a first step in determining the prey consumption by the blackspotted smooth-hound in the area. Materials and methods. A total of 151 blackspotted smooth-hounds caught by commercial fishermen in the Gulf of Trieste from 4 June 2002 to 4 June 2003 were examined in this study. The stomach contents were removed, sorted and identified to the lowest possible taxon using identification keys. Preys were counted and weighed. Frequency of occurrence (F%), relative abundance (N%), the percentage by weight (W%), the Index of Relative Importance (IRI), and its standardized value (%IRI) were calculated following standard procedures. For comparing the diet between four different size classes we calculate average prey weight, dietary diversity, average meal, and trophic level for each size class. Results. Atotal of 130 fish stomachs contained prey items.Crustaceanswere themost important prey items (IRI%= 56.14), whereas cephalopods were the second mostly preyed animals (IRI% = 20.2). Teleost fish and bivalves were also found in the stomachs. The most important prey species was Solecurtus strigillatus. Larger sharks consumed larger preys. Male and female sharks consumed similar food. Juvenile individuals consumed predominantly crustaceans, while cephalopods were more important in the diet of adult individuals. The calculated trophic index (TROPH) of M. punctulatus from northern Adriatic Sea was 3.7, showing that it is a highly carnivorous species. Conclusion. This study is a first step in determining prey consumption by Mustelus punctulatus which is, despite the fact that is still common in the area, a rather poorly known species. For elucidating the role of benthic sharks in the study area the further step would be to study the diet of a closely related common smooth-hound M. mustelus.
During the last two decades, an abundant selachian assemblage has been collected from the late Ypresian (NP12) fossiliferous sands of Prémontré (Aisne, northern France) but has received little attention. Sharks of the family Triakidae (Carcharhiniformes) are particularly well represented and all are described and figured herein. Among them, two new species of the genus Galeorhinus are described: G. duchaussoisi sp. nov. and G. louisi sp. nov.; these are compared to the common Paleogene G. ypresiensis which is refigured. Another triakid taxon, the genus Gomphogaleus gen. nov., is described. Most of the triakids have been recorded elsewhere in the North Atlantic region, suggesting a wider distribution than expected for these small sharks during the Paleogene. The present paper updates the list of selachians from Prémontré, bringing the number of taxa from 19 to 33 (including 22 sharks and 11 batoids) and improving our knowledge of the ancient North Atlantic Ypresian selachian fauna. Despite this vastly improved record, it is clear that fossil data are still very incomplete and insufficient for calibrating phylogenetic hypotheses of living forms. Review of the Prémontré fauna shows that the Triakidae were much more diverse and broadly distributed than at present, suggesting that the limited distribution and low diversity of living forms is probably a recent phenomenon.
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