Search results for "Fish fin"
showing 7 items of 7 documents
Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data
2017
Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in no…
On the tail ofErrivaspisand the condition of the caudal fin in heterostracans
2009
Articulated caudal fins of heterostracans are preserved in very rare cases. Their morphology and internal structure are completely unknown for the majority of species. One of the few preserved caudal fins belongs to the Early Devonian pteraspidid Errivaspis waynensis from the Welsh Borderland, UK. There are two different reconstructions of the tail: (1) strongly asymmetric, with a considerably longer ventral lobe, and a rather concave posterior margin (e.g. White 1935); and (2) almost symmetrical with an only slightly longer ventral lobe and a small notch in the posterior margin (e.g. Blieck 1984). A new reconstruction of the Errivaspis caudal fin, based on a detailed study of White's speci…
Looking for skin and gill parasites as biological tags for Atlantic bluefin tuna (Thunnus thynnus)
2008
Skin and gill parasites found in juvenile Atlantic bluefin tuna (Thunnus thynnus) caught in the Bay of Biscay, northeast Atlantic, were examined with the aim of finding biological tags. The degree of infection of different microhabitats was analyzed and the annual prevalence by species of parasite obtained. Of the specimens examined, 98% had parasites, and the gills were by far the most infected microhabitat, followed by the skin and the pectoral fin. Within the gill cavity, parasites were most commonly found in the afferent margins of the primary lamellae. Three species of Copepoda were identified, two species of Monogenea, and eleven Digenea. Thus, ten species (Digenea: Didymozoidae) and …
Meristic character counts and incidence of skeletal anomalies in the wild Diplodus puntazzo (Cetti, 1777) of an area of the south-eastern Mediterrane…
2006
The sharpsnout seabream (Diplodus puntazzo, Cetti 1777) is a species rarely found in coastal areas of Sicily, but is important in Mediterranean aquaculture. In order to detect the number of meristic characters and the main types of body deformation, 588 specimens of sharpsnout seabream were collected from a coastal zone of south-east Sicily (Licata, AG—Italy). Different sized classes were examined and the relationship between size and the number of meristic characters (number of fin rays) was found. The number of vertebrae, anal fin hard rays and dorsal fin hard rays was constant and did not vary with size. Seventeen types of skeletal and fin anomalies were observed, but no grave anomalies …
Vertical distribution of two sympatric labrid fishes in the Western Mediterranean and Eastern Atlantic rocky subtidal: local shore topography does ma…
2011
Changes in the shore topography (e.g. slope) occur at a scale of hundreds of meters in several locations in the Lusitanian and the Mediterranean Sea provinces. We tested whether differences in the bottom inclination might affect the vertical distribution patterns of two sympatric coastal labrid fishes, the rainbow wrasse Coris julis and the ornate wrasse Thalassoma pavo. Visual censuses were used to determine the distribution and abundance of these labrid species in high (‡30� ) and low (£3� ) slope rocky substrates covered by brown macroalgae and at two different depths (shallow, 4‐7 m, and deep 14‐20 m). Pectoral fin aspect ratio was used as an estimate of swimming performance to potentia…
Living on the Edge: Settlement Patterns by the Symbiotic Barnacle Xenobalanus globicipitis on Small Cetaceans
2015
The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped dolphins (Stenella coeruleoalba) that were stranded along the Mediterranean coast of Spain. Barnacles exclusively infested the fins, particularly along the trailing edge. Occurrence, abundance, and density of X. globicipitis were significantly higher, and barnacles were significantly larger, on the caudal fin than on the flippers and dorsal fin. Ba…
The musculature of the electric fish Eigenmannia virescens (South American green knife fish) characterized with cytochrome oxidase staining
1986
Using cytochrome C-oxidase staining, different types of somatic musculature were clearly distinguished in the gymnotoid fish Eigenmannia virescens. Except for a few thin fibres in the region of the horizontal septum, which stained faintly, no others in the trunk muscle stained. Strong staining appeared in the fibres of the anal fin muscles. According to the classification of fish musculature into white, intermediate and red, only the locomotory organ of this fish has red fibres, whereas the trunk muscles are white. The red muscles along the horizontal septum, found in all other fish which have been investigated in this respect, seem to be absent. This is noteworthy since the anal fin alone …