510 research outputs found
The argali (Ovis ammon antiqua) from the Magliana area (Rome)
During the Middle Pleistocene, the subspecies was widespread from Georgia to Portugal, though it is scantily recorded in local faunal assemblages of Southern Europe. Its occurrence in a few Late Pleistocene sites needs to be confirmed. In Italy, the subspecies is recorded in the late Galerian fauna of Visogliano (MIS 13 - 10) as well as in the Magliana area, where an incomplete skull was found at the beginning of the last century. Although the precise location where this specimen was found is unknown, on the basis of the results of the geochemical analysis performed on a small amount of sediment, sampled from the filling of the inner cavities of the horn-cores, and considering the stratigraphy of the area, the hypothesis that the skull comes from the deposits of the PG4 sequence (MIS14 partim - MIS13) cannot be ruled out. This hypothetical remark would confirm the occurrence in Italy of the argali in late Galerian faunas. The dimensions of Ovis ammon antiqua from the Magliana area fit well within the range of variability of the larger specimens, likely males, found at La Caune de L’Arago (France) (MIS 14-12), from which the Italian specimen differs in having less twisted and more dorso-ventrally curved horn-cores
Food habits of "Praemegaceros" cazioti (Depéret, 1897) from Dragonara Cave (NW Sardinia, Italy) inferred from cranial morphology and dental wear
S'ha estudiat l'adaptació alimentària de "Praemegaceros" cazioti (Depéret, 1897), en base a la rica mostra trobada als dipòsits del Pleistocè tardà de la cova de Dragonara (nord-oest de Sardenya, Itàlia). Amb aquest objecte, s'han pres en consideració els trets cranials, així com el gradient de desgast d'abrasió - atrició (mesodesgast), i els efectes produïts a l'esmalt dentari per les particules contingudes als vegetals, per l'acidesa i/o duresa del menjar i per la força i direcció dels moviments mandibulars (microdesgast). Els resultats de les anàlisis qualitatives i quantitatives són consistents amb una adaptació alimentària a una dieta mixta, tal com també ho són algunes característiques cranio-dentàries: en particular, el morro, més aviat quadrat, les grans àrees d'inserció del musculus masseter, el desenvolupament de la prominència massetèrica sobre el M', la profunditat i altura del corpus i ramus a l'angulus mandibulae, la superfície d'inserció reduïda del musculus temporalis a la mandibula i les dents hipsodontes. Els resultats de la nostra anàlisi suggereixen que el cèrvid de la Cova Dragonara era un animal de dieta mixta, que va incrementar el consum d'herba en comparació amb el seu possible ancestre.The dietary adaptation of "Praemegaceros" cazioti (Depéret, 1897) has been investigated on the basis of on the rich sample found in the Late Pleistocene deposits in Dragonara Cave (north-western Sardinia, Italy). To this end, we have taken into consideration cranial features as well as the abrasion-attrition wear gradient (mesowear) and the defects produced on tooth enamel by the particles contained in vegetables, by the acidity and/ or hardness of food and by the strength and direction of jaw movements (microwears). Results of qualitative and quantitative analyses of microwears are consistent with mixed-feeder dietary adaptation, as are some crania-dental features: in particular the rather square muzzle, the large insertion areas of musculus rnassetet; the developed masseteric prominence above M'; the depth and height of corpus and ramus at angulus mandibulae; the reduced insertion surface of musculus temporalis on the jaw and hypsodont teeth. Results of our analyses suggest that the cervid from Dragonara Cave was a mixed-feeder, increasing the consumption of grass as compared to its possible ancestor
Su Fossu de Cannas Cave (Sadali, central-eastern Sardinia, Italy): the earliest deposit holding Pleistocene megacerine remains in Sardinia
Recentment s'han descobert diverses restes de cèrvids als sediments arenosos, vermells i fortament cimentats que omplen la cavitat superior de la Cava Su Fossu de Cannas (Sadali, Sardenya centre-oriental), tallada a les calcàries del Mesozoic de Barbagia di Seulo. Es varen trobar les restes a la part de dalt d'una cova horitzontal, estreta. L'origen d'aquest passadís es pot deure a una fase erosiva antiga (Pleistocè Mitjà?) que va afectar els sediments que primàriament omplien la cova, com s'evidencia per l'erosió del conglomerat superior i la deposició posterior de sediments vermellosos lleugerament cimentats. Els espècimens analitzats fins ara mostren afinitats morfològiques estretes amb el megacerí endèmic de Sardenya "Praemegaceros" cazioti (Depéret, 1897). No obstant això, el cèrvid de Sadali es diferencia del darrer per la seva mida més gran, que supera l'espectre de variabilitat calculat per a l'espècie endèmica, i en alguns trets morfològics (tal com el corpu.s rnandibulae fondo i corbat), aixi com per presentar unes dents proporcionalment més petites í, sobretot, per un metacarpià més gràcil. Els trets peculiars dels espècimens de Sadali suggereixen la seva pertinença a una nova espècie. No obstant això, de moment ens estimem més no batejar-la i anomenar el cèrvid de Sad ali "Praemegaceros" n. sp., a l'espera de noves dades que permetin afinar la seva diagnosi. El cèrvid de Su Fossu de Cannas es pot considerar com el representant més primitiu del gènere "Praemegaceros" a Sardenya i l'ancestre de "Praemegaceros" cazioti.Several cervid remains have recently been discovered in the sandy, red-coloured and strongly cemented sediment filling the uppermost cavity of the Su Fossu de Cannas Cave (Sadali, central-eastern Sardinia), cut into the Mesozoic limestone in the Barbagia ofSeulo. The remains were found on the ceiling ofa narrow, horizontal underground cave. The origin of this passage may be due to an ancient erosional phase (Middle Pleistocene?), which affected the sediments formerly filling up the cave, as evidenced by the erosion of the uppermost conglomerate and by the further deposition of reddish, slightly cemented sediments. The specimens analysed thus far show close morphological affinities with the endemic Sardinian megacerine "Praemegaceros" cazioti (Depéret, 1897). However, the Sadali cervid differs from the latter in its larger size, exceeding the range of variability calculated for the endemic species, and in some morphological features (such as the depth and curved corpu.s mandibulaei, as well as in its proportionally smaller teeth and, notably, its elongated, slender metacarpal. The peculiar features of the Sadalí specimens suggest its attribution to a new species. Nevertheless, for the moment, we prefer to name the Sadali cervid "Praemegaceros" n. sp., awaiting new data to present the diagnosis. The Su Fossu de Cannas cervid can be regarded as the most primitive representative of the genus "Praemegaceros" in Sardinia and the ancestor of the endemic species "Praemegaceros" cazioti
Elephas falconeri from Spinagallo Cave (South-Eastern Sicily, Hyblean Plateau, Siracusa): a preliminary report on brain to body weight comparison
El crani d' Elephas (Palaeoloxodon) falconeriBusk 1867 de la cova de Spinagallo (Pleistocè Mitjà, sud-est de Sicilia, Itàlia) forneix l'evidència de que la mida relativa del cervell d'aquest elefantva augmentar significativament degut a les condicions d'aïllament. El pes del cervell de l'espècie continental Elephas (Palaeoloxodon) antiquus Falconer & Cautley, 1847, del Pleistocè mitjà tardà d'Itàlia, correspon a devers 1/600 del seu pes corporal, mentre que als exemplars nans adults procedents de la cova de Spinagallo aquesta proporció és de 1160. El canvi significatiu en les proporcions del cervell a Elephas [alconeri està relacionat amb la necessitat de mantenir un volum minim del cervell funcional, fins i tot quan el crani es redueix molt. A més, són particularment evidents característiques pedomòrfiques a la forma del crani d' Elephas[alconeti, semblant al crani d' exemplars juvenils d' elefants vivents i extingits, especialment als que pertanyen als gèneres Elephas i Loxodonta. S'ha estimat la massa corporal d'elefants nans i continentals en base a noves equacions basades en l'alçària a la creu i la circumferència de les potes, comprovades als elefants vivents. L adult d' Elephas falconeri hauria d'haver tingut una alçària màxima a la creu de devers 120 cm i un pes de devers 150 kg , amb valors devers el 70% inferiors en l'altària i devers el 98,4% en pes en comparació amb les alçàries i pesos promig estimades per als espècimens italians d'Elephas antiquus.The skull of Elephas (Palaeoloxodon) falconeri Busk, 1867 from Spinagallo Cave (Middle Pleistocene; south-eastern Sicily, Italy) provides evidence that the brain of this dwarf elephant significantly increased in relative size as a result of its geographic isolation. Indeed, the brain weight of continental Elephas (palaeoloxodon) antiquus Falconer & Cautley, 1847, from the late Middle Pleistocene of Italy, corresponded to about 1/1600 of its body weight, whereas for the adult dwarf specimens from Spinagallo Cave, this ratio was about 1/60. The significant change in brain proportions in Elephas [alconeri was linked to the need to maintain minimal functional brain volume, even when the skull was greatly reduced in dimensions. Moreover, paedomorphic features are particularly evident in Elephas falconeri skull shape, similar to the skull of juvenile specimens of extant and fossil elephants, especially those belonging to the Elephas and Loxodonta genera. We have estimated the body mass of dwarfed and continental elephants on the basis of new equations based upon shoulder height and pad circumference and tested on living elephants. On the basis of our results, the adult Elephas falconeri should have had a maximum height at withers of about 120 cm and a weight of about 150 kg, with values of about 70 % in height and about 98.4% in weight as compared with the average height and weight estimated for Italian specimens of Elephas antiquus
LARGE MAMMAL TURNOVER AND DIVERSITY FROM THE PLIOCENE TO THE PLEISTOCENE IN ITALIAN PENINSULA
Patterns of mammalian species turnover, richness, and faunal composition are assessed on the basis of relative sampling quality and correlated with climatic changes. The most important faunal renewals took place at the early to middle Villafranchian, middle to late Villafranchian, and Early to Middle Pleistocene transitions. The turnover phase at Triversa to Montopoli FU transition corresponds to the Middle Pliocene climate worsening, and can be considered a starting point for the dispersal phases that occurred during the Middle and Late Pliocene. Around 1.9-1.7 Ma (Olivola and Tasso FUs) both a clear increase in diversity as well as a turnover pulse can be detected. The so-called "wolfevent" has to be regarded not only as a dispersal phase but also as a true turnover pulse that is related to the climatic changes occurring at the end of Pliocene. Finally, the transition from Early to Middle Pleistocene faunas represents a major community reorganization (dispersal followed by turnover phase) that shows a significant and progressive rejuvenation coincident with the onset of 100 ka climate cyclicity and vegetation changes related to the climate worsening. The results obtained support the argument that climatic changes are a forcing factor in the first appearances (number of first appearances (Nf ) and rate quotient of first appearance (RQf), including migrations) of mammal taxa.
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