نتایج جستجو برای: proboscidea mammalia
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Pedetidae, or springhares, are represented by a single extant genus (Pedetes) and five extinct ones (Parapedetes, Megapedetes, Propedetes, Rusingapedetes and Oldrichpedetes of which the latter two are new). The fossil record of pedetids tends to be scanty, but remains have been found in Southern Africa, East Africa, the Maghreb, the Arabian Peninsula, Turkey and Greece. Most of the localities h...
There are at least four conceivable factors which could be responsible for the maintenance of anisogamous sex: (1) long-term group selection, (2) short-term ecological, natural selection, (3) trade-offs between female sexual fertility and parthenogenetic fertility and (4) female dependence on a male gametic contribution. There is evidence for the action of each of the first three factors, while...
Many hypotheses have been postulated regarding the early evolution of the mammalian brain. Here, x-ray tomography of the Early Jurassic mammaliaforms Morganucodon and Hadrocodium sheds light on this history. We found that relative brain size expanded to mammalian levels, with enlarged olfactory bulbs, neocortex, olfactory (pyriform) cortex, and cerebellum, in two evolutionary pulses. The initia...
The presence of Toxoplasma gondii and Leptospira spp. antibodies was investigated in 74 manatees (Trichechus inunguis [Mammalia: Sirenia]) kept in captivity in two rescue units in the northern region of Brazil. Antibodies to T. gondii were detected in 29 (39.2%) of 74 animals by using the modified agglutination test (titer, 1:25). For antibodies against Leptospira spp., sera were diluted 1:50 a...
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