The poorly known coleoid genus Atractites Guembel, widespread in Tethyan Triassic to Lower Jurassic deposits, is formed of a number of nominal species, most of which represented by incomplete phragmocones and a few by isolated tela. Only a few authors have so far discussed the original species diagnosis of Atractites alpinus Gumbel, 1861 (by monotypy type species of the genus) and the type material, pointing out the difficulties of relating the tela to known phragmocones. After a discussion of aulacocerid forms related to Atractites and their distinctive suprageneric- and generic-rank characters, the present authors distinguish different morphological types among the species attributed to the genus: in particular, the usually poorly-preserved rostral portions are reexamined on the basis of material coming from the Alps, the Dinarids and the Apennines. In the light of the existing evidence, further details are given on rostral morphology of well-preserved specimens and on the different rostral and phragmocone morphologies and relationships, on one side confirming the essential validity of Guembel (1861)’s diagnosis, on the other one pointing out the necessity to exclude a number of unrelated forms ascribed to the genus. A systematization of the forms currently ascribed to Atractites is proposed.
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|Titolo:||Remarks on the genus Atractites Gümbel, 1861 (Coleoidea: Aulacocerida)|
|Data di pubblicazione:||1994|
|Appartiene alla tipologia:||01a Articolo in rivista|