Bouleiceras (Hildoceratidae,Ammonitina) from the lower Toarcian (Jurassic) of the Iberian Range (Spain): Taxonomy,stratigraphic distribution and insights on its dispersal

Bouleiceras is a very rare genus among the rich assemblages of ammonoids from the lower Toarcian of the Iberian Range. So far, only two dozen specimens have been recorded in numerous field campaigns carried out since 1965 by different authors. The interest of this taxon lies in its peculiar paleogeographical distribution in comparison with most other ammonoids of the same age. A review of these specimens is carried out, including those obtained in previous works and others recently collected in selected localities. Based mainly on the differences in the shape of the ventral section and the suture line, seven species have been identified; two of which are new: Bouleiceras ibericum nov. sp. and Bouleiceras? betetensis nov. sp. All the reviewed specimens are recorded in the Semicelatum Subzone of the Tenuicostatum Zone and the Elegantulum Subzone of the Serpentinum Zone from the Central Sector and the Levantine Sector of the Iberian Range. The global distribution of the genus is summarized from the known data, and its possible dispersal routes are analyzed, as well as the factors that could have conditioned them.     

Les ammonites traditionnellement regroupées dans la sous-famille des Bouleiceratinae (Hildoceratidae, Toarcien) : aspects phylogénétiques, biogéographiques et systématiques

The genera usually considered into the Bouleiceratinae subfamily belong in fact to different lineages of the Hildoceratidae family. An approach using paleogeographical, stratigraphical and morphological arguments on one hand and a cladistic approach on the other hand have allowed to separate 3 clusters with different paleogeographical and stratigraphical localisations. These are:

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the Bouleiceratinae s.s. (genera Bouleiceras, Nejdia and Kohaticeras) from lower Toarcian;

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the Leukadiellinae (genera Leukadiella and Renziceras) from middle Toarcian;

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and the Paroniceratinae (genera Frechiella, Paroniceras and Oxyparoniceras) from middle and upper Toarcian. These latters are mainly present and the Tethyan domain, but are also known in the NW of Europe and especially in France where new populations have been studied in the Causses, in the centre-ouest and in the Lyon area. New taxa have been erected here: Oxyparoniceras (Neoparoniceras) nov. sub. gen., O. (N.) brocardi nov. sp. and O. (N.) sciaui nov. sp.