Revision of the permian ammonoid family thalassoceratidae Hyatt

Ontophylogenetic studies of Paleozoic ammonoides

“…However, we were able to reveal stable pat terns, to confirm the phylogenetic relationship between some groups, and, conversely, to reject some previously accepted relationships. Our studies of the internal structure of the embryonic talassoceratid shell (Leonova, Boiko, 2011) confirmed the practical value of the method used, so the possibility to reveal differ ences at the earliest stages allows us to make conclu sions about the close relationship between individual groups of order and family ranks.…”

“…Another subfamily of this family, Aris toceratinae, presents the opposite situation: the con servative suture line is combined with the deviant shell morphology (Fig. 5b) (Leonova, Boiko, 2011). All representatives of the series of Aristoceras Allothalassoceras…”

“…Reconstruction of phylogenetic relationships in families: (a) Popanoceratidae(Leonova et al, 2005), the main stage of development is change in the first and second internal lateral lobes (thick line), (b) Thalassoceratidae(Leonova, Boiko, 2011), on the right branch is progressive complication of the suture line with conservative external morphology, on the left branch is the change in the sculpture at the conservative suture line.…”