Cécile Poplin’s research while affiliated with Muséum National d'Histoire Naturelle and other places

Muséum national d'Histoire naturelle—Département Histoire de la Terre, USM 0203—UMR 5143 CNRS, Paléobiodiversité et Paléoenvironnement, CP 38 8 rue Buffon-75231 Paris cedex O5—France; 1 mhhamel@yahoo.fr; 2 cpoplin@mnhn.fr ABSTRACT—A full description and diagnosis are given of Lawrenciella schaefferi Poplin 1984, from the Pennsylvanian (Late Carboniferous) of Kansas, U.S.A. This taxon is only known by braincases and associated parasphenoids, which are exceptionally well preserved as phosphatic nodules. The external and internal morphology of the endocrania were studied from serial sectionings which allowed detailed three-dimensional reconstructions. The study shows that, besides synapo-morphies inherent to basal actinopterans, L. schaefferi displays a set of very peculiar features such as prespiracular fossae, intracranial ossicles, and paired anterior myodomes for nonocular eye muscles. Another conspicuous feature, the noto-chordal canal ending blindly anteriorly, has been observed until now only in more advanced Triassic actinopterans. The anatomical characters of L. schaefferi indicate, in the light of recent cladistic analyses, that this Carboniferous taxon is a relatively advanced actinopteran compared to basal forms such as Kentuckia, Mimia, or Moythomasia.

A new actinopterygian fish Yaomoshania minutosquama gen. & sp. nov., from the Upper Permian of the Dzungaria [Junggar] Basin in China is described. The material consists of two very fragmentary specimens showing almost exclusively scale rows. The arrangement of the scale rows of the holotype resembles the reversion lines of acanthodian caudal fins and of cheirolepids. The size and shape of the scales, and the diminishing size of the scales along the rows, is similar to those of acanthodians and those actinopterygians with small scales such as Cheirolepis. However, the histology of the scales demonstrates features that are found in more advanced actinopterygians: superimposed ganoine lamellae, the arrangement of dentine tubules and pulp canals, buried odontodes stacked on each other to make the ornamental ridges, and an asymmetric pattern of growth achieved by extensive remodelling (resorption and redeposition) of all layers of the scale. Yaomoshania minutosquama is proposed as a small-scale bearing, basal actinopterygian, different from Cheirolepis, but characterized by advanced histological characters.

Les Aeduellidae (Pisces, Actinopterygii) carbonifères et permiens :systématique et étude phylogénétique préliminaire. Geodiversitas 27 (1) :17-33. RÉSUMÉ Les genres et espèces d'aeduellidés actuellement connus sont présentés. Une analyse phylogénétique, impliquant 12 autres actinoptérygiens et un porolé-piforme comme groupe extérieur, confirme que les Aeduellidae constituent un groupe naturel. Mais les relations de parenté de ses taxons, dont un genre, Bourbonnella, apparaît comme paraphylétique, ne sont pas entièrement éclair-cies, probablement en raison du nombre de données manquantes. Cette famille présente une mosaïque de caractères plésiomorphes et apomorphes pour les actinoptérygiens. Les relations phylogénétiques des Aeduellidae avec les autres Actinopteri basaux (= Palaeoniscimorpha) ne sont pas non plus éclaircies. En effet l'analyse ne révèle pas d'affinités particulières avec les groupes avec lesquels on avait tenté de les rapprocher par le passé. ABSTRACT The carboniferous and permian Aeduellidae (Pisces, Actinopterygii): systematics and preliminary phylogenic study. The aeduellid genera and species already known are presented. A phylogenet-ic analysis, involving 12 other actinopterygians and a porolepiform outgroup, confirms that the Aeduellidae are a natural group. But their interrelationships are not cleared up completely, probably because of many missing data; in par-ticular one genus, Bourbonnella, appears as paraphyletic. This family has a mosaic of plesiomorphic and apomorphic actinopterygian characters; their relationships with the other basal Actinopteri (= Palaeoniscimorpha) are not clearer. In fact the analysis does not show particular affinities with the groups with which they have been tentively compared in the past.

The aeduellid genera and species already known are presented. A phylogenetic analysis, involving 12 other actinopterygians and a porolepiform outgroup, confirms that the Aeduellidae are a natural group. But their interrelationships are not cleared up completely, probably because of many missing data; in particular one genus, Bourbonnella, appears as paraphyletic. This family has a mosaic of plesiomorphic and apomorphic actinopterygian characters; their relationships with the other basal Actinopteri (= Palaeoniscimorpha) are not clearer. In fact the analysis does not show particular affinities with the groups with which they have been tentively compared in the past. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.

Revised diagnoses of the family Tarrasiidae and of Tarrasius (Visean of Scotland) and Paratarrasius (Namurian of North America) are presented. These are used in a phylogenetic analysis also comprising one theoretical outgroup, three sarcopterygians as part of the outgroup, and eleven Palaeozoic, Triassic, and Recent actinopterygians, and based on a matrix of 75 characters of head and body. The results are that: (1) Polypterus is the sister group of the other Actinopterygii (= Actinopteri): (2) the analysed Actinopteri are a monophyletic group (Palaeoniscimorpha): and (3) Tarrasiids are monophyletic and are the sister group of the other analysed Actinopteri. This scheme supports the most recent studies in indicating that Tarrasiidae are close to stem actinopterygians.

Revised diagnoses of the family Tarrasiidae and of Tarrasius (Visean of Scotland) and Paratarrasius (Namurian of North America) are presented. These are used in a phylogenetic analysis also comprising one theoretical outgroup, three sarcopterygians as part of the outgroup, and eleven Palaeozoic, Triassic, and Recent actinopterygians, and based on a matrix of 75 characters of head and body. The results are that: (1) Polypterus is the sister group of the other Actinopterygii (= Actinopteri); (2) the analysed Actinopteri are a monophyletic group (Palaeoniscimorpha); and (3) Tarrasiids are monophyletic and are the sister group of the other analysed Actinopteri. This scheme supports the most recent studies in indicating that Tarrasiidae are close to stem actinopterygians.

The genusBourbonnella(Actinopterygii, Aeduellidae): revision and description of a new species from the Stephanian (Upper Carboniferous) of Montceau-les-Mines (Massif Central, France). After a revision of the diagnosis of the family Aeduellidae, the previously known species of the genus Bourbonnella have been briefly recorded from a systematic point of view with, in particular, a reappraisial of their diagnoses and, consequently, that of the genus: B. guilloti, type species from the Autunian of Buxières-les-Mines, B. sottyi from the Stephanian of Montceau-les-Mines (both from Massif Central) and B. sp. indet. from the Virgilian (= Stephanian) of New Mexico (USA). An other undetermined Autunian species from Germany is finally attributed to the genus Aeduella. Bourbonnella fourrieri n. sp., from a new fossiliferous Stephanian level of Montceau-les-Mines, is described. It differs from the three other species by its deeper body, the greater area of small scales supporting the dorsal fin, the proportions of the head in regards to the body and the meristics of fin rays. Its scales are devoid of dentine. According to our present knowledge, Bourbonnella seems to be a euryhaline, equatorial and tropical genus at the Carboniferous - Permian turnover.

Several fossils from the Late Carboniferous of Montceau-les-Mines, France, are referred to a new taxon of fossil hagfish. Two specimens display impressions of two pairs of tooth rows that are strikingly similar in shape and organization to the horny teeth of modern hagfish. In addition, by its slender body shape, this new taxon is more suggestive of modern hagfish than the only previously known fossil form from the Carboniferous of the USA. Living hagfish being exclusively marine, this discovery raises the question of the reputedly freshwater environment of the Montceau-les-Mines ‘Konservat-Lagerstätte’.

Several fossils from the Late Carboniferous of Montceau-les-Mines, France, are referred to a new taxon of fossil hagfish. Two specimens display impressions of two pairs of tooth rows that are strikingly similar in shape and organization to the horny teeth of modern hagfish. In addition, by its slender body shape, this new taxon is more suggestive of modern hagfish than the only previously known fossil form from the Carboniferous of the USA. Living hagfish being exclusively marine, this discovery raises the question of the reputedly freshwater environment of the Montceau-les-Mines 'Konservat-Lagerstätte'. © 2001 Académie des sciences / Éditions scientifiques et médicales Elsevier SAS.

Two new species of deep-bodied Paleozoic actinopterygians, Aesopichthys erinaceus gen. nov., sp. nov. and Proceramala montanensis gen. nov., sp. nov., are described from the Upper Chesterian, Upper Mississippian (Namurian E2b, Lower Carboniferous) Bear Gulch Limestone of Montana, USA, and the new family Aesopichthyidae is erected for them. These two fishes share features usually associated with deep body and deep head specializations, particularly in Palaeoniscimorpha, such as a shortened gape, tall maxilla, vertical Suspensorium, deepened flank scales and an elongate dorsal fin. Aesopichthys in particular, for which more complete information is known, also possessed a suite of very specialized adaptations in feeding mechanism, ganoine sculpturing, fin form, and cranial defensive structures that have strong ethological implications. These features include small mobile premaxillae, a spinous and apparently rotatable posteroventral infraorbital, lobed pectoral base, and partially webbed pectoral, dorsal, anal and caudal fins.Within a general scheme of interrelationships of primitive actinopterygians, these two new taxa pertain to Palaeoniscimorpha, i.e., basal Actinopteri. Then, from a cladistic analysis limited, beside these two new taxa, to Wendyiehthys and Cyranorhis (two other already described actinopterygians from Bear Gulch), Platysomus, and Cheirolepis, it appears that the Aesopichthyidae display no close relationship to the Platysomidae but should be the sister group of the Rhadinichthyid-group i.e., [Cyranorhis + [Rhadinichthyidae + Wendyiehthys]].