Considerations about the Late Cretaceous genus <i>Chirocentrites</i> and erection of the new genus <i>Heckelichthys</i> (Teleostei, Ichthyodectiformes) - A new visit inside the ichthyodectid phylogeny

The author describes briefly the osteology of the three valid species of the Late Cretaceous genus Chirocentrites. He shows that only the type species, C. coroninii, belongs to this genus. He creates the new genus Heckelichthys for the two other species, C. microdon and C. vexillifer, with the latter as type species. The phylogeny of the Ichthyodectidae is studied. The systematic position of Chirocentrites and Heckelichthys is specified

<i>Ridewoodichthys</i>, a new genus for <i>Brychaetus caheni</i> from the marine Paleocene of Cabinda (Africa): re-description and comments on its relationships within the Osteoglossidae (Teleostei, Osteoglossomorpha)

The marine osteoglossid “Brychaetus” caheni from the Lower Paleocene of Cabinda (Africa) is re-studied. It does not belong to the genus Brychaetus because of differences in teeth and premaxilla shape. It is assigned to the new genus Ridewoodichthys on the basis of its caudal skeleton, which differs from that of all other known fossil and Recent Osteoglossidae

Les Ichthyodectidae (Teleostei, Ichthyodectiformes) des schistes bitumineux de l’Aptien (Crétacé inférieur) de Guinée Équatoriale et du Gabon

L’ostéologie et les relations phylogénétiques de trois ichthyodectidés des schistes bitumineux de l’Aptien de Guinée Équatoriale et du Gabon sont étudiés. La première espèce était déjà connue sous le nom de Chirocentrites guinensis. Cette espèce est valable mais son squelette montre qu’elle appartient non pas à Chirocentrites mais à Chiromystus, un genre caractérisé par des rayons pectoraux élargis et branchus et un axe vertébral court. Les différences entre Chiromystus et Cladocyclus sont soulignées pour démontrer la validité de Chiromystus. La deuxième espèce n’est connue que par quelques fragments crâniens, en particulier les mâchoires. Elle est nouvelle et représente un nouveau genre, Africathrissops weileri, qui paraît primitif et proche de Thrissops. Sa fossette d’articulation pour le carré est formée par le rétroarticulaire et l’articulaire sans participation de l’angulaire. La troisième espèce est inédite et représente aussi un nouveau genre, Verraesichthys bloti, caractérisé également par un squelette axial court mais son crâne et sa ceinture scapulaire diffèrent nettement de ceux de Chiromystus. Le squelette caudal d’un ichthyodectidé indéterminé mais évolué est également décrit

Ostéologie et relations de <i>Catervariolus</i> (Teleostei, "Pholidophoriformes") du Jurassique moyen de Kisangani (Formation de Stanleyville) en République Démocratique du Congo

The osteology of Catervariolus, a small fish from the Middle Jurassic of Kisangani (Stanleyville Formation) in the Democratic Republic of Congo, is studied in detail on the basis of more than 600 specimens. It is shown that the genus is monospecific and that Catervariolus passaui is a junior synonym of Catervariolus hornemani. Catervariolus is less evolved than the "classical" teleosts. Indeed, its ural vertebra 1 is still divided into two distinct centra. It still has an opisthotic, a surangular, a prearticular, coronoids, a Meckelian bone, six epurals and nine hypurals. Its scales are lepisosteid and not cycloid. The inclusion of Catervariolus in the order "Pholidophoriformes" is justified by some specialized characters of its skeleton. It possesses an impair vomer, an ossified supraoccipital, a quadrate with a quadratic process, a toothed dermobasihyal and a foramen for the efferent pseudobranchial artery pierced in the parasphenoid. Long epineurals are fused with the neural arches. Indeed, these apomorphies separate the "Pholidophoriformes" from the Pachycormiformes, their plesiomorphic sister-order. The toothed laterodermethmoids of Catervariolus form the middle of the upper jaw and reject laterally the premaxillae. The African fossil fish does not yet have an hypoethmoid associated with the vomer, neither a subtemporal fossa nor a bony prootico-intercalar bridge. It has three supraorbitals, three large postorbitals, a unique small supramaxilla and three toothed coronoids on the lower jaw. The toothed part of its dentary is elongated and not descending ventrally. The leptolepid notch of the oral border of the dentary is feebly developed or even absent. The combination of these characters shows that Catervariolus is the most primitive of all hitherto described "Pholidophoriformes"

<i>Eoplethodus chaneti</i> gen. et sp. nov. de l’Albien (Crétacé) marin de Provence (France) et l’évolution du squelette caudal chez les Tselfatiiformes (Osteichthyes: Teleostei)

The caudal skeleton of Eoplethodus chaneti gen, and sp. nov., a fossil teleost from the marine Albian (Cretaceous) of France is described. This fish belongs to the cohort Clupeocephala and the order Tselfatiiformes (=Bananogmiiformes). The caudal skeleton of E. chaneti still offers a well developed preural 1 vertebra, three epurals, a pair of stegurals, and normal preural 1 hemal arch and parhypural. It is thus more primitive than the one of the Plethodidae, the family grouping all the other genera of this order, where the preural 1 vertebra is reduced, the epurals and parhypural lost, the preural 1 hemal arch atrophied or lost, and the pair of stegurals changed into a false preural 1 neural spine. E. chaneti allows a better understanding of the evolution of the caudal skeleton within the Tselfatiiformes

Sur la position systématique et les affinites de Greenwood- della Tockensis Taverne, L. et Ross, P.H. 1973 (Pisces Elopiformes) de l’Aptien inférieur de l’Ile d’Helgoland (Allemagne)

The relationships of Greenwoodella tockensis TAVERNE, L. and Ross, P. H., 1973 are discussed. This fish is referred to a new family, Greenwoodellidae,and placed in the sub-order Albuloidei (Pisces Elopiformes) as an ancestor of the Albulidae and Pterothrissidae

Ostéologie et relations de <i>Ligulella</i> (Halecostomi, Ligulelliformes nov. ord.), poisson du Jurassique moyen de Kisangani (Formation de Stanleyville) en République Démocratique du Congo

The osteology of Ligulella, a very small halecostome fish from the Middle Jurassic of Kisangani (Stanleyville Formation) in the Democratic Republic of Congo, is studied in detail on the basis of more than 100 specimens. It is shown that the genus is monospecific and that Ligulella fourmarieri is a junior synonym of Ligulella sluysi. The dermic bones of the skull roof are covered by a thin and smooth layer of ganoin. The lateral borders of the skull roof are ornamented with a fringe of large bony spines. A small toothed laterodermethmoid is located medially at the symphysis of the upper jaw and rejects laterally the premaxillae. The quadrate is devoid of a bony quadratic process. Both quadrate and symplectic articulate with the lower jaw. Based on its characters Ligulella has to be positioned in the neopterygian phylogenetic tree between the Pachycormiformes and the "Pholidophoriformes", allowing the creation of a new and peculiar ordinal status for it, the Ligulelliformes nov. ord

Ostéologie et relations phylogénétiques de <i>Steurbautichthys ("Pholidophophorus") aequatorialis</i> gen. nov. (Teleostei, "Pholidophoriformes") du Jurassique moyen de Kisangani, en République Démocratique du Congo

The osteology of Steurbautichthys ("Pholidophorus") aequatorialis gen. nov. from the Middle Jurassic of Kisangani (Stanleyville Formation, Songa Limestones) in the Democratic Republic of Congo is studied in detail. This fish, about 25 cm long, is marked by a large head, a rather aquiline snout and a small oval median rostral, which does not reach to the tip of the snout. The broad nasals meet on the mid-line anteriorly, but are separated by the frontals posteriorly. The anterior extremity of the frontals remains broad and is partly covered by the nasals. The parietals are large quadrangular bones meeting medially and bearing a small pit-line, prolonging the supraorbital sensory canal. The orbitosphenoid joins the lateral ethmoids anteriorly. The interorbital opening between the orbitosphenoid, the pleurosphenoids and the parasphenoid is well developed. The parasphenoid is toothless, and shows well-developed basipterygoid processes. The foramen for the efferent pseudobranchial artery is perforated in the parasphenoid at the root of the basipterygoid process. The jaws bear small conical teeth. The toothed narrow anterior parts of the laterodermethmoids compose the tip of the upper jaw and separate the two premaxillae from each other. The nasal processes of the laterodermethmoids are enlarged and cover the greatest part of the underlying mesethmoid. The premaxillary is small and devoid of an ascending process. The maxillary is long and exhibits a slightly curved oral border. There are two supramaxillaries. The lower jaw is elongated and articulates with the quadrate at the level of the orbital posterior border. The dentary increases in height posteriorly but its oral border is almost rectilinear with a small notch just behind the toothed region. The long and stout meckelian bone rests in a groove of the internal face of the lower jaw. The surangular forms a weakly pronounced coronoid process. The entopterygoid is broad and partly toothed. The ectopterygoid is longer, narrower and toothless. The quadrate exhibits a well-developed quadratic process. The preopercle possesses a long dorsal branch and a broad but very short ventral branch. The preopercular sensory canal bears only a few secondary tubules. The caudal skeleton is nearly homocercal. The two ventral hypurals are narrow. The first dorsal hypurals are fused in a plate. There are at least 3 uroneurals. There are only very few fringing fulcra on the fins. The scales are of lepisosteid shape, with a peg and socket articulation. The surface of the ganoin is feebly ornamented and the posterior border of the scale is smooth. Comparisons are made with Pholidophorus sensu strict, some species of Pholidophorus sensu lato, other pholidophorid genera and other pholidophoriform families. The generic validity of Steurbautichthys is demonstrated. A new pholidophoriform phylogeny is proposed in which Steurbautichthys is referred to the Ankylophoridae, a family of primitive Pholidophoriformes characterized by its laterodermethmoids with an enlarged nasal process and a smaller anterior toothed or tuberculated tip, rejecting laterally the premaxillae. The genera Eurycormus, Ankylophorus, Lehmanophorus, Pholidophoristion, Neopholidophoropsis, Siemensichthys, the species "Pholidophorus" germanicus and probably the genera Pholidorhyncodon and Eopholidophorus also belong to this family

Les affinites systématiques des Téléostéens fossiles de l’ordre des Ichthyodectiformes

The author studies the osteological relationships between Ichthyodectiformes and other lower Teleosts. The skeleton of the Ichthyodectiformes shows positive evidence of close affinity with the Osteoglossomorpha. The author suggests that Ichthyodectiformes be placed in the super-order Osteoglossomorpha with ordinal rank

Osteology and relationships of <i>Acrorhinichthys poyatoi</i> gen. et sp nov (Pycnodontiformes) from the marine Late Cretaceous of Lebanon

The osteology of Acrorhinichthys poyatoi gen. et sp. nov., a pycnodontid fish from the marine Cenomanian (Late Cretaceous) of Lebanon, is studied in detail. The new fossil genus belongs to the order Pycnodontiformes, but is less evolved than the Pycnodontidae. It still exhibits a few bony plates (= tesserae) in the gular region, 3 teeth on the premaxilla and 5 teeth on the dentary, and its parietal is devoid of a brush-like process. It shares a few characters with Akromystax, the most primitive taxon within Pycnodontidae, characters lost in the other members of the family