Trend und Phylum im Säugetiersystem [Vývojové trendy a taxony v systému savců]

Stránky 193–199
Citace KRETZOI, Miklós. Trend und Phylum im Säugetiersystem [Vývojové trendy a taxony v systému savců]. Lynx, nová série. Praha: Národní muzeum, 2001, 32(1), 193–199. ISSN 0024-7774 (print), 1804-6460 (online). Dostupné také z:
Lynx, nová série | 2001/32/1

This paper intends to demonstrate cases where the trend in the evolution of mammal dentition overshadows the original phyletic succession by producing parallel or even convergent structures, disturbing the morphological bases of phyletic taxonomy. For example: (1) Myospalacid evolution produced dental structures in Allosiphneus (Allosiphneinae subfam. nov.) – at least in the lower molars – which does not differ from the structure in the arvicolid (lemmine) Mictomys only on a taxonomic level higher than species. (2) Hemicyonidae (= Agriotheriidae) and Ursidae significantly differ in the early stages of the evolution of the lower carnassial, but produce at higher levels of evolution, structures in the M1 composed of different cusp elements (lingual border of the talonid in Indarctos composed of metaconid-entoconid-hypoconulid in descending cusp height with the opening, i.e. the deepest point at the end of the tooth). In contrast to the ursids, where the talonid is bordered on the lingual side by entoconid and new cusplets decreasing frontally, with the deepest point (opening) of the talonid basin lying between metaconid and the anterior secondary cusplet of the entoconid complex. (3) Premolars in carnivore evolution testify to a diphyletic origin. In caniform evolution the metaconid remained a low posterior cingulum and a “pseudo-metaconid” developed on the posterior crest of the protoconid. In feliform evolution the metaconid increased in size to a strong posterior cusp on which a new cingulum developed in the Miocene, presenting the aspect of a corresponding caniform tooth. (4) Finally, attention should be paied to the serious confusion of trend with phylum, for example the suggestion of phyletic succession from Ichthyosauria to Cete. In other words, an attempt was made to describe what was really three evolutionary levels as phyletic units (subclasses).

Sdílení na sociálních sítích