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Skull ontogeny; cranial arteries; mammalian phylogeny
Abstract:
Mammals of the insectivoran grade have always roused considerable interest, mainly because of their presumed similarity to the fi rst ancestors of this group. While the morphology of adult specimens is relatively easy to access and thus well investigated embryos are rare and much less studied, in spite of their multiplicity of attributes. In order to provide additional morphological characters the ontogeny of the skull of Hemicentetes semispinosus was investigated using three serial sections through the heads of embryos and neonates respectively. The chondrocranium with cartilage replacing bones and dermal bones of the youngest embryo as well as the larger arteries in the posterior region of the heads of Hemicentetes semispinosus and Potamogale velox were graphically reconstructed. The findings of 70 skull and cranial artery characters were compared mainly with data from literature on several insectivore species. Already published hypotheses on phylogenetic relationships could be partially corroborated. Investigations of more primitive tenrecs and otter shrews on one hand and on e.g. golden moles and elephant shrews on the other hand are required in order to further evaluate differences and possible synapomorphies.
