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Two specimens of the pycnodont Haquelpycnodus picteti from the Cenomanian (Late Cretaceous) of Lebanon possess small non-dental odontodes flanking the teeth inside the oral cavity. These odontodes are distributed labially with respect to the vomerine and prearticular dentition, corresponding to the internal face of the cheek and in front of the maxilla. They have no relation to any of the bones in the mouth region and were situated in the endo-oral mucosa. This dentition pattern resembles that of the earliest osteichthyans and stem-gnathostomes. SEM-investigation of the non-dental odontodes demonstrates a thick layer of orthodentine covered by two thin outer layers of acrodin. The microchemical composition of these odontodes corresponds to those of the dermal scales (derived from odontodes) that are distributed in the integument of the same examined specimen. Both morphology, ultrastructure, and topographic relationships demonstrate that these structures are dermal and not dental odontodes. The reappearance of dermal odontodes in the dentition of individual specimens of Haquelpycnodus thus reflects the latent capacity of the endo-oral mucosa to form non-dental odontodes. These odontodes probably exerted lateral pressure to the content within the oral cavity, which took place synchronously with the prehensile movements of the incisors. [ABSTRACT FROM AUTHOR]

By comparing the morphological variability of two groups of pycnodonts, the Coccodontoidea and the Nursalliini, the author demonstrates that in the Late Cretaceous these two groups had adopted completely different blauplans. Throughout the Cretaceous and the Eocene, the Nursalliini maintained the typical shape of the pycnodonts, rounded and flattened. The Cocodontoidea expressed 21 new species that belonged to 17 new genera, across which there was extraordinary biodiversity. The typical body plan was almost abandoned, and elongated, and somewhat very tapered, forms emerged (Stenoprotome), which lived alongside very short and very high fish. Indeed, this period produced the shortest and the highest fish that have ever lived (Maraldichthys). Indeed, while the more highly variable groups (Coccodontoidea) represented a punctiform episode in the evolutionary history of pycnodonts, remaining confined to the arm of Tethys (central Lebanon) and to the time period corresponding to the lower upper Cenomanian, the morphologically more conservative groups (Nursalliini) colonised the seas of the entire planet from the Cretaceous to the Eocene, even surviving the great mass extinction period corresponding to the Mesozoic-Cenozoic passage. Thus, the enormous biodiversity of Coccodointoidea did not represent a selective advantage over the environmental crisis at the end of the Cretaceous. [ABSTRACT FROM AUTHOR]

Here, a fossil egg case that contains a well-preserved embryo is described. The embryo is characterised by (i) a rostral cartilage, (ii) some ribs, (iii) and a well-developed stinger; (iv) absence of thoracolumbar synarcual. This represents an unique combination of characters which demonstrate that the batoid that produced the egg case was a completely new form, possibly a stem–Myliobatiformes, which remains undetermined in the absence – to date – of any comparable adult specimen. SEM morphological analysis demonstrates that the wall of the fossil egg case was multilaminate, made up of collagen fibres (with a thickness of 2–4 μm): an ultrastructure that has been positively compared to the egg case of living Rajiformes (Raja asteria) and Myliobatifirmes (Hemitrygodon akajeri). The egg case also contains a mass that is interpreted as the remains of yolk sac, internally organised in platelets with a diameter of 25–35 μm. Since in living Myliobatiformes the egg cases disappears from inside the uterus before the end of the embryogenesis, the described fossil is interpreted as an embryo that was prematurely emitted by the pregnant mother, such as an abortion of a batoid dated to the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Until now it was believed that the discovery of the Early Cretaceous fossil fish of the Santana Formation, Araripe Plateu, Cearà, Brazil, dated back to the period between 1817 and 1820, when the two Austrian naturalists Johann Baptist von Spix and Carl Friedrich Philipp von Martius made an exploratory journey in Brazil. New documents show, however, that it was the German naturalist, naturalized Dutch, Maria Sibylla Merian (1647-1717) who came into possession of at least one specimen of fossil fish from the Araripe Plateau, during her exploratory journeys made in Suriname between 1669 and 1701. Merian inserted an unequivocal drawing of this fish (probably a specimen of Rhacolepis buccalis, insided in a typical concretion nodule from the Santana Formation) in Plate LIX of the book by Jorg Eberhardt Rumph (1628-1702) entitled "D'Amboinsche Rariteitkamer, etc.", which was published posthumously (1705) and which Merian was commissioned to illustrate. The pre-dating of this important scientific event places the discovery of the fossil fish of the Early Cretaceous of Cearà among the first discoveries of fossil fish that took place on a global level, reinforcing the importance of this locality also under a historical point of view. [ABSTRACT FROM AUTHOR]

The author describes the new species of pycnodont, Nursallia fenestrata n. sp., from the Akrabou Formation, dated to the lower Turonian (Late Cretaceous), outcropping in the Moroccan High Atlas Mountains. The new species is a mediumsized pycnodont, characterized by the presence of the following unique combination of the anatomical traits: (i) vomerine teeth with crown with a circular outline and a median notch, (ii) large, well-developed temporal fenestra, (iii) extremely complex intervertebral joints, due to the presence of three pairs (anterior and posterior) of zygoapophyses on each both ventral and dorsal arcocentra, (iv) bar-scales extending exclusively in the dorsal region, never ventrally beyond the vertebral column. The new species has some highly developed characteristics typical of the Nursalliini tribe, such as the complexity of the intervertebral joints. In fact, in Nursallia fenestrata n. sp. the articulations between adjacent arcocentra are hyper-complex throughout the spine. On the other hand, the new species Nursallia fenestrata n. sp. demonstrates that it possesses skeletal characteristics hitherto never found within the Nursalliini tribe, as is the case with the parietal window. Finally, the new species represents the first report of a skeletal remains - moreover in a very peculiar state of conservation (in a three-dimensional calcareous nodule) - of a pycnodon within the Akrabou Formation, dated to the Lower Turonian, outcropping in the Moroccan High Atlas. [ABSTRACT FROM AUTHOR]