Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supra-specific taxa of Chondrichthyan fishes. Part B: Batomorphii. 4a: Order Rajiformes - Suborder Myliobatoidei - Superfamily Dasyatoidea - Family Dasyatidae - Subfamily Dasyatinae - Genera: <i>Amphotistius, Dasyatis, Himantura, Pastinachus, Pteroplatytrygon, Taeniura, Urogymnus</i> and <i>Urolophoides</i> (incl. supraspecific taxa of uncertain status and validity), Superfamily Myliobatoidea - Family Gymnuridae - Genera: <i>Aetoplatea</i> and <i>Gymnura</i>, Superfamily Plesiobatoidea - Family Hexatrigonidae - Genus: <i>Hexatrygon</i>

Part B of this series, comprising the Batomorphii is continued with taxa of the Myliobatoidei. The tooth morphology of representatives of eight genera (incl. supraspecific taxa of uncertain status and validity) of the family Dasyatidae, two of Gymnuridae and one of Hexatrygonidae is described and illustrated by SEM-photographs. A differential diagnosis for a final conclusions on myliobatoid odontology will be given in a forthcoming issue dealing with the last myliobatoid taxa

Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of Chondrichthyan fishes. Part A. Selachii. 1b: Order: Hexanchiformes - Family: Chlamydoselachidae. 5: Order: Heterodontiformes - Family: Heterodontidae. 6: Order: Lamniformes - Families: Cetorhinidae, Megachasmidae; Addendum 1 to 3: Order Squaliformes; Addendum 1 to 4: Order: Orectolobiformes; General Glossary; Summary part A

The morphology of the microteeth of the following taxa is described and illustrated with SEM-photographs in order to elucidate the interrelationships within the shark orders and families concerned and also from odontological point of view. Contribution 1b: The monotypic single genus of the hexanchiform Chlamydoselachidae. The tooth morphology of C. anguineus is compared with that of taxa of the only other hexanchiformes. The dental histology is commented on, and the dental vascular type is re-examined in order to understand the root form. The results are summarized in an odontological diagnosis for the genus. Investigational results on dental morphology, histology and vascularization recommend a reconsideration of the systematic position of the Chlamydoselachidae, which show a closer relation to Orectolobiformes than to Hexanchidae. Contribution 5: The three genera Tropidodus, Gyropleurodus and Heterodontus of the heterodontiform family Heterodontidae as once proposed by Gill, 1862. The differences in tooth morphology are only of interspecific signification. Contribution 6: The genera of the monotypic families Cetorhinidae and Megachasmidae. The morphology of the small teeth in both families is characteristic for filter-feeders. Cetorhinus exhibits irregular size and shape of its small teeth and a distinct ontogenetic heterodonty in its dentition. Megachasma, in contrast, shows small teeth of equal size and shape indicating a relatively recent adaptation to filter-feeding. Contribution 3, addendum 1: The squalid species Scymnodon squamulosus and Scymnodon obscurus attributable to the genus Zameus, proposed by Jordan and Fowler in 1903 and revalidated by Taniuchi and Garrick in 1986. Odontological investigations indicate a synonymy of Zameus and Scymnodalatias with Scymnodon. Contribution 4, addendum 1: The type species of the monotypic orectolobid genus Sutorectus. The results are summarized in a diagnosis for the genus and offer hardly any odontological arguments for distinguishing Sutorectus from Orectolobus

A new partial skeleton of a palaeospinacid shark (Neoselachii, Synechodontiformes) from the Albian of northern France, with a review of the taxonomic history of Early Cretaceous species of <i>Synechodus</i> Woodward, 1888

An articulated skeleton of a palaeospinacid shark from the Saint-Pô Formation (Albian, upper Lower Cretaceous) of the Boulonnais (northern France) is described and illustrated for the first time, inclusive of tooth vascularisation and histology. The specimen comprises portions of the neurocanium, splanchnocranium, pectoral girdle, vertebrae, numerous teeth and about 12 000 dermal denticles, but no dorsal fin spines. Its dental morphology is unique in combining relatively smooth crown surfaces in anterior teeth, a strongly reticulated ornamentation in latero-posterior teeth and an intermediate ornamentation in larger antero-lateral teeth. The differential diagnoses of three nominal species of Synechodus Woodward, 1888 that have often been recorded from Albian strata (i.e., S. dubrisiensis (Mackie, 1863), S. nitidus Woodward, 1911 and S. tenuis Woodward, 1889) were based mainly on tooth ornamentation. This observation would favour the conspecificity of these three forms, as has been suggested previously by several authors. However, it does not rule out the possibility of more than one species of Synechodus in the Albian of the Anglo-Paris Basin. Such divergent ornamentation might be characteristic of more than one species, meaning that differentiation would be more complex. Awaiting a thorough revision of these taxa, a review of their taxonomic history is presented here. For the time being, the specimen from the Boulonnais is left in open nomenclature and referred to as Synechodus sp