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B chromosomes in Palinurus gilchristi) (Crustacea, Decapoda).
No full textB chromosomes in {Palinurus gilchristi} (Crustacea, Decapoda)
Coluccia E, Cannas R, Salvadori S, Cau A, Deiana AM
Dipartimento di Biologia Animale ed Ecologia, Università di Cagliari, Italy
We analyzed mitotic and meiotic chromosomes of {Palinurus gilchristi} Stebbing, 1900, a South African spiny lobster exploited by intensive fishery activity. So far the chromosome complement of this species is unknown. Mitotic and meiotic chromosomes from testis tissue were studied. Metaphase plates, obtained by air-drying techniques were Wright’s stained and C-banded.
Late prophases/metaphases I bivalents showed cross, ring and dumb-bell figures; some unpaired chromosomes, completely C-positive, were present. To study the chromosome number, mitotic and metaphase II chromosomes and metaphase I bivalents were counted. Numerical variability was observed (2n=120 ÷132, n=60 ÷ 72), that could be due to the presence of heterochromatic, asynaptic B chromosomes. Two types of Bs have been identified depending on their size: small and micro Bs; their total number varied from 3 to 7.
It is noteworthy that in the two other congeneric species, {P. elephas} and {P. mauritanicus} we studied, B chromosomes with similar morphology have been Among Decapoda, B chromosomes have been found in two Nephropidae species, {Nephrops norvegicus} and {Homarus americanus}
Impact of the feeding habits of the Great Cormorant Phalacrocorax carbo sinensis on the lagoon fish stocks in central western Sardinia
No full textMonitoraggio delle attività di predazione del cormorano sulle specie ittiche di interesse produttivo. Provincia di Oristano.
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Trophic interactions among three rajids, Raja asterias, Raja brachyura and Raja miraletus in the central-western Mediterranean
No full textRecent records of Schedophilus ovalis (Osteichthyes, Centrolophidae) from Sardinian waters (Central-Western Mediterranean)
No full textThe occurrence of several young and adult specimens of Schedophilus ovalis (Cuvier, 1833), found at different depths along the coasts of Sardinia, was documented. Morphological and meristic characters of some specimens were reported. The recent increase in the presence of this species indicates that it is progressively colonising the Central-western Mediterranean
Monitoraggio delle attività di predazione del cormorano sulle specie ittiche di interesse produttivo. Provincia del Sulcis.
No full textThe phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): dromaeosaurid or flightless bird?
No full textThe exceptionally well-preserved Romanian dinosaur Balaur bondoc is the most complete theropod known to date from the Upper Cretaceous of Europe. Previous studies of this remarkable taxon have included its phylogenetic interpretation as an aberrant dromaeosaurid with velociraptorine affinities. However, Balaur displays a combination of both apparently plesiomorphic and derived bird-like characters. Here, we analyse those features in a phylogenetic revision and show how they challenge its referral to Dromaeosauridae. Our reanalysis of two distinct phylogenetic datasets focusing on basal paravian taxa supports the reinterpretation of Balaur as an avialan more crownward than Archaeopteryx but outside of Pygostylia, and as a flightless taxon within a paraphyletic assemblage of long-tailed birds. Our placement of Balaur within Avialae is not biased by character weighting. The placement among dromaeosaurids resulted in a suboptimal alternative that cannot be rejected based on the data to hand. Interpreted as a dromaeosaurid, Balaur has been assumed to be hypercarnivorous and predatory, exhibiting a peculiar morphology influenced by island endemism. However, a dromaeosaurid-like ecology is contradicted by several details of Balaur’s morphology, including the loss of a third functional manual digit, the non-ginglymoid distal end of metatarsal II, and a non-falciform ungual on the second pedal digit that lacks a prominent flexor tubercle. Conversely, an omnivorous ecology is better supported by Balaur’s morphology and is consistent with its phylogenetic placement within Avialae. Our reinterpretation of Balaur implies that a superficially dromaeosaurid-like taxon represents the enlarged, terrestrialised descendant of smaller and probably volant ancestors
Sustainable fishing in the Mediterranean for Bluefin Tuna: a case study of ancestral fishing technologies and contemporary practices
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