First record of the ichthyodectiform fish Cladocyclus from eastern Gondwana: an articulated skeleton from the Early Cretaceous of Queensland, Australia

Cladocyclus is a genus of ichthyodectiform fish that is best known from fossils found in shallow marine Cretaceous deposits in Brazil and Morocco. Herein, a new species of Cladocyclus is described on the basis of a fossil that comprises an articulated skull and anterior part of the body, preserved as part and counter-part in what was originally a single eroded nodule of fluvially-deposited volcanolithic sandstone from the Lower Cretaceous (upper Albian) portion of the Winton Formation near Isisford, central-western Queensland, Australia. This specimen represents the first record of Cladocyclus in eastern Gondwana, and indicates that species of this fish may also have inhabited freshwater environments. The new species is assigned to the genus Cladocyclus based on the morphology of the cleithrum (the arms are oriented at approximately 90 degrees to each other) and a mandibular articular facet that incorporates portions of the angular, the articular and the retroarticular. Cladocyclus geddesi sp. nov. can be distinguished from other congeners based on the possession of a more elongate horizontal arm of the cleithrum and a supraoccipital crest that is gently convex posteriorly. This discovery greatly expands the geographic range of Cladocyclus, and supports the idea of a distinct southern fish fauna in the seas surrounding the fragmenting Gondwanan landmasses during the mid-Cretaceous

First occurrence of a mawsoniid (Sarcopterygii: Actinistia), Mawsonia soba sp. nov., in pre-Aptian Cretaceous deposits from Cameroon

International audienceCoelacanth remains from the Lower Cretaceous (pre-Aptian) freshwater deposits of the Babouri Figuil Basin, Northern Cameroon are described as a new taxon Mawsonia soba sp. nov. based on two characters: four openings in the dentary for the branch of the trigeminal nerves and an extremely rugose and disorganized ornamentation of the bones. M. soba sp. nov. known by some three-dimensionally partially preserved specimens represents the first actinistian described from Cameroon. This discovery attests the presence of Mawsonia in the African counterpart of the continental pre-rift and rift environments where only Brazilian members were known so far. The fact that the Cameroonian coelacanth belongs to a new species suggest a certain endemism at least in this African basin

<i>Axelrodichthys araripensis</i> Maisey, 1986 revisited

<p><i>Axelrodichtys</i> is a genus of fossil coelacanth of the family Mawsoniidae with a wide spatial and temporal range, spanning from the Aptian/Albian of Brazil to the Campanian of France. In light of new discoveries in recent years a renewed interest in <i>Axelrodichthys</i> has emerged. Here we offer new insights on the type species – <i>A. araripensis</i> – based on a complete new description of all its morphological characters and a comparative study of several other Mawsoniidae. A relatively large sample composed of 113 specimens of <i>A. araripensis</i> and associated Mawsoniidae species was observed. Among the newly observed features are the broad aspect of premaxillae supporting the anterior opening of the rostral organ; a unique pattern of skull roof ornamentation; the basioccipital; a passage of nerves in the prootic; the passage for the superior ophthalmic nerve; the anocleithrum; and ossified zygal plates. Observation of two juvenile specimens in different growth stages allowed for the inference of negative allometric growth in the epicaudal lobe. Morphological comparisons pointed out that <i>M. lavocati</i> is more closely associated with the <i>Axelrodichthys</i> than with <i>Mawsonia</i>, therefore we included it in the <i>Axelrodichthys</i> genus as <i>A. lavocati.</i></p