NEW DATA ON THE FLORA AND FAUNA FROM THE ?UPPERMOST CARBONIFEROUS-LOWER PERMIAN OF BUXIERES-LES-MINES, BOURBON L'ARCHAMBAULT BASIN (ALLIER, FRANCE). A PRELIMINARY REPORT more

Bull. Soc. geol. France, 2000, t. 171, n° 2, pp. 239-249 j New data on the flora and fauna from the ?uppermost Carboniferous-Lower Permian of Buxieres-les-Mines, Bourbon l'Archambault Basin (Allier, France). A preliminary report J. Sebastien STEYER1, Francois ESCUILLIE2, Jean-Marc POUILLON2, Jean BROUTIN3, Pierre DEBRIETTE4, Pierre FREYTET3, Georges GAND5, Cecile POPLIN1, Jean-Claude RAGE1, Jacques RIVAL2, Joerg W. SCHNEIDER6, Stanislav STAMBERG7, Ralf WERNEBURG8 and Gilles CUNY9 Key words. - Fauna, Flora, Autunian, French Massif central, Palaeoenvironment, Biostratigraphy. Abstract. - New fossils from the ?uppermost Carboniferous - Lower Permian have been found at Buxieres-les-Mines (Massif central, France). In this preliminary article we report on algae, stromatolites, palynomorphs, macroflora, ostracods, insects, elasmobranchs, acanthodians, actinopterygians and amphibians. Elasmobranchs and amphibians are diversified compared with those of other European localities. Most taxa indicate lacustrine deposits and an Asselian age, and permit us to adress the question of the palaeoecosystem evolution of the Bourbon-l'Archambault Basin, during the Lower Permian. Nouvelles donnees sur la faune et la flore du ?Carbonifere superieur-Permien inferieur de Buxieres-les-Mines, bassin de Bourbon l'Archambault (Allier, France). Inventaire preliminaire Mots cies. - Faune, flore, Autunien, Massif central francais, Paleoenvironnement, Biostratigraphie. Resume. - De nouveaux fossiles ont ete decouverts dans le ?Carbonifere superieur - Permien inferieur de Buxieres-les-Mines (Massif central, France). Cet article preliminaire en dresse l'inventaire. II comprend des algues, des stromatolithes, des palynomorphes, une macroflore, des ostracodes, des insectes, des elasmobranches, acanthodiens, actinopterygiens, et des amphibiens. Les elasmobranches et les amphibiens sont tres diversifies par com- paraison avec ceux d'autres gisements europeens. La plupart des taxons indiquent des milieux de depot lacustres datant de TAsselien, et permettent aussi de completer les connaissances sur 1'evolution des paleoecosystemes du bassin de Bourbon-l'Archambault au Permien inferieur. version franc;aise abregee Introduction Cet article correspond a une synthese de donnees nouvelles provenant pour l'essentiel de fouilles realisees dans et autour d'une exploitation de charbon a ciel ouvert a Buxieres-les-Mines, dans la partie sud-ouest du bassin carbonifere et permien de Bourbon-l'Archambault (Allier). Ce dernier est subdivise en deux ensembles, le sous-bassin de Souvigny et celui de l'Aumance (fig. 1) ou est situe Buxieres-les-Mines. Ce site minier est Fun des derniers du Massif central ou les Char- bonnages de France exploitent encore la houille dans des niveaux traditionnellement nommes "autuniens" [terme utilise ici sensu Gand et al., 1997a, b], et plus precisement dans les formations de Buxieres et de Renieres (fig. 2). Les mines de charbon a ciel ouvert de Buxieres ont deja livre, il y a quelques annees, des vegetaux (palynomorphes, stromatolithes, macroflores), des ostracodes, des ecailles et des coprolithes de poissons et quelques os isoles de tetrapodes. Les travaux actuels ont complete les connaissances paleontologiques et surtout sedimentologiques du bassin. Recemment, en coope- ration avec les Houilleres des Bassins Centre et Midi (HBCM), l'Association Rhinopolis et une Convention europeenne de Recherche ont organise des fouilles systematiques de sauvetage avant la fermeture de la mine. La collecte des specimens est faite directement sur le front de taille ou dans des deblais selectionnes sur place. Les decouvertes sont nombreuses et, a plus grande echelle, elles completent les etudes sur la biostratigraphie et la paleoecologie du bassin de Bourbon- l'Archambault. Une liste floristique et faunique est proposee : Algues - Plaziatella colleniaeformis, Ellenbergerella attenuata, BaltzereUa aumanciana. Stromatolites - planchers et colonnes. Palynomorphes - Thymospora sp., Laevigatosporites sp., Punctatosporites sp., Lycospora sp., Punctatisporites sp., Calamospora sp. (spores de pteridophytes), Florinites sp., Potonieisporites sp., Vesicaspora sp., Alisporites sp., lllinites sp., Protohaploxypinus sp., Vittatina sp., Costapollenites sp., Bissacates sp. (grains de pollen). Laboratoire de Paleontologie, UMR 8569 du CNRS, Museum national d'Histoire naturelle, 8 rue Buffon, 75005 Paris, France. 2 Association Rhinopolis, 6 rue Claude Hettier de Boislambert, 03800 Gannat, France. 3 Laboratoire de Paleobotanique et Paleoecologie, Institut d'Ecologie Fondamentale et Appliquee, FR3-CNRS, Universite Pierre et Marie Curie, 12 rue Cuvier, 75005 Paris, France. 4 HBCM, B.P.175, U.E. Blanzy, 71307 Montceau-les-Mines, France. 5 UMR 5561 Biogeosciences du CNRS, Centre des Sciences de la Terre, Universite de Bourgogne, 6 Bd Gabriel, 21000 Dijon, France. 6 Freiberger Universitat, Institut fur Geologie / Bereich Palaontologie, Bernhard von Cotta Strasse 2, D-09596 Freiberg, Germany. 7 Muzeum vychodnich Cech, Eliscino nabrezi 465, CZ500 01 Hradec Kralove, Czech Republic. 8 Naturhistorisches Museum Schloss Bertholdsburg Schleusingen, Burgstrasse 6, D-98553 Schleusingen, Germany. 9 Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK. Manuscrit depose le 2 mars 1999; accepte apres revision le 20 septembre 1999. Bull. Soc. geol. Fr., 2000, n° 2 240 J.S. STEYpR et al. Macroflore - Psaronius sp., Sigillaria sp., Stigmaria sp., Sphenophyllum pblongifolium, Annularia stellata, Catamites cruciatus, Calamites sp., Calamostachys tuberculata, Zygopteris- sp., Pecopteris bucklandii, Pecopteris densifolia, Pecopteris foeminaeformis, Pecopteris hemitelioides, Pecopteris pseudoreopteridia, Pecopteris unita, Pecopteris sp., Sphenopteris sp., Alethopteris zeilleri, Odontopteris reichiana, Odontopteris sp., Linopteris sp., Autunia conferta, Dichophyllum flabelliferum, "Callipteris" sp., Hermitia (al. Walchia) sp., ICordaites, ICardiocarpus. Ostracodes - indetermines. Insectes blattoi'des - Compsoblatta sp., Sysciophlebia sp., ISpiloblatta. Elasmobranches - Orthacanthus (Orthacanthus) buxieri, Bohemiacanthus sp., cf. Lissodus. Acanthodiens - Acanthodes sp. Actinopterygiens - Paramblypterus sp., lAeduella blainvillei, IWatsonichthys pectinatus, Progyrolepis heyleri, palaeoniscoides indetermines. Amphibiens - Onchiodon sp., Cheliderpeton sp., Melanerpeton sp., Melanerpeton cf. gracile. Bilan La faune (en particulier celle des elasmobranches et des amphibiens) de Buxieres est relativement diversified par com- paraison avec celle d'autres bassins permiens et/ou carboniferes d'Europe. La plupart des taxons indiquent des milieux de depot lacustres. Les ailes de blattoides, les dents d'elasmobranches (notamment de Bohemiacanthus) et les branchio- saures {Melanerpeton) suggerent un age asselien (Permien basal). Certains vegetaux sont cependant caracteristiques du Stephanien superieur (Carbonifere superieur) et d'un depot plutot palustre. L'autochtonie des ailes de blattoides n'est egalement pas prouvee. Le gisement paleontologique de Buxieres-les-Mines est actuellement le seul site permien qui soit fouille systema- tiquement en France. Avant la fermeture de la mine en 2001, de prochaines fouilles-sauvetages devraient permettre de deceler d'eventuels melanges (ou remaniements) floristiques, de completer les etudes biochronologiques et paleoenvi- ronnementales, notamment sur 1'evolution du paleoecosysteme en relation avec la dynamique du bassin et d'effectuer des correlations stratigraphiques avec les autres bassins de Laurasie. INTRODUCTION This article corresponds to a synthesis of new data coming from excavations in and around a coal opencast mine at Buxieres-les-Mines (hereafter, referred to as Buxieres), in the southwestern part of the Bourbon-l'Archambault Basin (northern Massif central, France) (fig. 1). The latter is sub- divided into the Aumance (in which is located Buxieres), and the Souvigny sub-basins. The fossils from Buxieres come from Autunian levels. The "Autunian" is no longer considered as a continental stage by European geologists, but as a lithostratigraphic unit (Group of formations sensu Gand et al. [1997a, b]). From the end of the nineteenth century to the 1950s, various fossils were recovered in the Renieres and Buxieres Formations (fig. 2) : silicified woods, numerous plant remains [Bougneres, 1961], fish sca- les and fish coprolites [de Launay, 1888; Berthoumieu, 1903; Letourneur, 1953], and stegocephalian amphibians [de Launay, 1888; Guillot, 1958]. Uranium prospecting by the "Compagnie Generale d'Ex- ploitation des Matieres nucleaires" (COGEMA) [Mathis and Brulhet, 1990], mining in Autunian coals by the "Houilleres des bassins Centre et Midi" (HBCM) [Debriette, 1992], geological map survey by the "Bureau de Recherches Geo- logiques et Minieres" (BRGM) [Turland et al, 1990] and university studies [Paquette, 1980; Debriette, 1985; Courel et al., 1989] increased the knowledge of this basin in stra- tigraphical, sedimentological, and palaeontological fields. These studies provided new data dealing with palynology [Paquette et al, 1980; Chateauneuf et al, 1980; Paquette, 1980], ostracods [Damotte et al, 1992], algae and stroma- tolites [Freytet, 1997, 1998; Freytet et al, 1992, 1999], and vertebrates [Heyler, 1969; Heyler and Poplin, 1990], * x xj Crystalline basement | + + + | Gipcy-Bouibon ridge Fig. 1. - Geographical and geological setting. A. Location of the Bour- bon-l'Archambault Basin. b. Simplified geological map of the Permo-Car- boniferous Bourbon-l'Archambault Basin [after Paquette and Feys, 1989, modified]. Fig. 1. - Contexte geographique et geologique. A. Localisation du bassin de Bourbon-l'Archambault. b. Carte geologique simplifiee du bassin per- mo-carbonifere de Bourbon-l'Archambault [d'apres Paquette and Feys, 1989, modifie]. Bull. Soc. geol. Fr., 2000, n° 2 AUTUNIAN FLORA AND FAUNA OF BUXIERES-LES-MINES (FRANCE) 241 uftUUri ajlu SUPERGROUPS UTHOSTRATIGRAPHY (DEBRIETTE 1992) Formations Members Trias Saxonian Clusor A(- D i Renfere B At • '■ ~ ■rr,*~' ^* • . • t -;. • -'. i.'. Reniere A Autunian At At- Supra Buxieres At- Buxi&res Infra Buxieres •* , • ' . .•*/ ^ ''"' • '"■ * '** 'L+ Conglomerat \>-i,'M* + + + Stephaman "Buxieres inferieur" lOOin r, 0 1 *V/'M:yl + + A//j/''y'l * + ■* + Wl-j/f * + + VA'/'f + + ■* + #•/*•/+ + + + + + 4 + +V/.-r/ + + + + + w + + + + +X+ + + 4 + + -t\ + + + + + V + + + F [+_+JCrystalline rocks [V^/Jsandstones |3-"jr |Argillites Ash tuff (At) ^^^Coal frT^Bituminous shales Fig. 2. - Section in the Bourbon-l'Archambault Basin (zone of the maxi- mum thickness), with the traditional position of the Stephanian-"Autu- nian" limit [after Debriette, 1992, modified]. F = the fossiliferous studied section. Ca. Carbonates: At. Ash tuff level. Fig. 2. - Coupe dans le bassin de Bourbon-l'Archambault (zone a epais- seur maximale), avec la position traditionnelle de la limite Stephanien- "Autunien" [d'apres Debriette, 1992, modifie]. F = section fossilifere etudiee. Ca. Carbonates; At. Cinerites. The rich Autunian flora and fauna from the coal opencast mines at Buxieres gave rise to uncoordinated collecting which have enriched various private collections. In order to coordinate collecting and avoid uncontrolled scattering of fossils, the Rhinopolis Association (an association estab- lished to collect and curate fossils from Buxieres), and a European Convention (a working group of European paleon- tologists and geologists) have undertaken prospections and excavations, with the help of the HBCM [Escuillie et al, 1996]. Owing to this organization, discoveries have increa- sed during the last few years. THE FOSSILIFEROUS SITE The fossils come from a large opencast mine close to Buxie- res, in which the working face is slowly moving. They have been collected in the upper part (fig. 2 : F) of the Buxieres Formation which comprises beds of coal and bituminous shales. The formation belongs to the "Autunian" sensu Cha- teauneuf et al. [1980], Paquette [1980], Paquette and Feys [1989], Turland et al. [1990], Debriette [1992]. The "Au- tunian" unconformably overlies the Stephanian; its thick- ness ranges approximately from 200 to 900 m. It is overlain by the "Saxonian" group, which shows an unconformity with the upper Triassic layers (fig. 2). The stratigraphic sec- tion of the mine which is worked for palaeontological pur- poses today is illustrated figure 3. SYSTEMATIC OVERVIEW Plants Algae and stromatolites Buxieres has yielded non-marine algae and stromatolites. They have been found in layers which form the dolomitic and silicified levels (fig. 3) [Paquette, 1980; Freytet, 1997, 1998; Freytet et al, 1992, 1999]. These latter are affected by shrinkage cracks and they include traces of roots of Pe- copteris (i.e., stem fragment of Psaronius with the charac- teristic adventitious root mantels) and ostracod shells. Algological aspects The remains belong to Plaziatella colleniaeformis (thin, erected filaments, in micritic laminations), Ellenbergerel- la attenuata (septate filaments, 4 um in diameter, with attenuated extremities), and Baltzerella aumanciana (non-septate filaments, erected, 10-12 pm in diameter). El- lenbergerella attenuata is very rare, whereas B. aumanciana forms continuous tuff-like layers, the thickness of which reaches 500 um, or fascicles 500 um wide and 1-2 um high. One may question whether B. aumanciana is a species re- duced to its sheath or its cell walls (therefore E. attenuata should be a species living in the jelly of B. aumanciana) or E. attenuata is a trichome and B. aumanciana is the sheath of the same botanical species. In both cases, the si- licification has been very precocious (a few days or weeks after the death of the trichome). Stromatolitic aspects The stromatolites make up small columns (2-3 cm high and 1-2 cm wide), continuous layers (1-2 cm thick), and mil- limetric coatings around Psaronius (i.e., adventitions root mantels of Pecopteris). Columns and continuous layers are made up by almost only B. aumanciana, with exceptionally some filaments of E. attenuata. The silicified coatings of Psaronius are generally made of laminations of Plaziatella colleniaeformis or rarely of laminations of B. aumanciana. Palynomorphs The most complete palynological study of the Buxieres For- mation was made by Doubinger [in Paquette et al, 1980]; it deals with coal seams named "Couche du bas Toit", and with an ash tuff level named "lien blanc" (fig. 3). Only the Bull. Soc. geol. Fr., 2000, n° 2 242 J.S. STEYER et al. Legend : see Rg.2, plus .- Siltstone E?n3 Dolomitic levels Bioturbation ^ ^ Spore & pollen grains (J) Catamites sp. (jj Cardiocarpus sp. Cordaites sp. Ostracods ^ Blattoid wings or " Insect horizon " "^g? Acanthodians Actinopterygians Elasmobranchs = Elasm. Branchiosauridae = Branch. Eryopidae and Archegosauridae = Eryop. " lien blanc " = Lb " lien vert" = Lv " Couche du Toit" = CT " Couche du bas Toit" = CBT Acanth. Actin. PALEONTOLOGY Ichnes CBT Flora Fauna Inv. Acanth. Actin. . Elasnrj Brai Branch. Eryop. i i i ■2m Fig. 3. - Detail of the fossiliferous section (F on figure 2) of Buxieres-les-Mines (Allier, France) with the stratigraphic distribution of taxa. Fig. 3. - Coupe stratigraphique detaillee (F, sur la figure 2) de Buxieres-les-Mines (Allier. France) avec la repartition des taxons. palynological association from the "Couche du Toit" has been here re-evaluated. The palynological associations from the "lien blanc" and "Couche du bas Toit" are quoted from Paquette et al. [1980]. Therefore, these palynomorphs come from beds located below the levels which have yielded the other fossils. On the other hand, the bottom of the studied section has produced palynomorphs only. Three palynomorph associations were easily distinguished in these lower beds. The "Couche du Toit" association (named "association palynologique type A" by Paquette et al. [1980]) comprises two palynological assemblages. The first one is mainly composed of pteridophyte spores (Thymospora, Laevigato- sporites, Punctatosporites, Lycospora, Punctatisporites and Calamospora) which correspond to a coal-swamp palaeoen- vironment. Monosaccate and bisaccate pollen grains are not abundant there. The second assemblage from the "Couche du Toit" is characterized by a higher number of monosac- cate (Florinites, Potonieisporites), non-striated bisaccate (Vesicaspora, Alisporites, Illinites), striated bisaccate (Pro- tohaploxypinus), and polyplicate (Vittatina, Costapollenites) pollen grains. These forms show botanical affinities with cordaitaleans and conifers and are suggestive of a meso- xerophytic plant association dominated by gymnosperms. The composition of this assemblage, dominated by pollen grains, is reminiscent of the "Autunian", whereas the first one (dominated by spores) shows a Stephanian pattern. This suggests that the "Couche du Toit" represents a transition age between the Stephanian and the "Autunian". According to the correlation chart of Schneider et al. [1995], the Stephanian comprises the Kasimovian and a part of the Gzhelian, whereas the "Autunian" in its type area would comprise the upper Ghzelian and Asselian. Therefore, the "Couche du Toit" does not compulsorily represent the limit between Gzehlian and Asselian. But this result is partly dif- ferent from that previously stated by Paquette et al. [1980], who suggested an "Autunian" age for the "Couche du Toit". The "lien blanc" association, named "association paly- nologique type B" by Paquette et al. [1980], is charac- Bull. Soc. geol. Fr., 2000, n° 2 autunian flora and fauna of buxieres-les-mines (france) 243 terized by a high abundance of Thymospora, a low propor- tion of Laevigatosporites, Punctatosporites, Florinites, whereas Bissacates, Lycospora, Punctatisporites and Cala- mospora are (very) rare. This suggests a late Carboniferous age [Paquette et al, 1980]. The "Couche du bas Toit" association, named "associa- tion palynologique type D" by Paquette et al. [1980], is characterized mainly by Lycospora, and Calamospora, Lae- vigatosporites, Punctatosporites, Florinites, Bissacates. This suggests a late Carboniferous age [Paquette et al, 1980]. This astonishing successsion of floras is a frequent prob- lem at the Carboniferous-Permian transition (see below). Macroflora Most of the available specimens from the area of Buxieres were not collected during recent excavations. According to the re-evaluation of an unpublished review [Vetter, 1984] based on a collection kept at the Buxieres town hall, the 25 following species are known from the Aumance sub-Ba- sin (i.e., Buxieres place sensu lato, "Descenderie Saint-Hilaire", "Decouverte des Creuses", "Carriere Delabre-Meillers"): Si- gillaria sp., Stigmaria sp., Sphenophyllum oblongifolium (germov and kaulfuss) Unger, Annularia stellata schlotheim ex wood, Catamites cruciatus (sternberg) brongniart, Catamites sp., Calamostachys tuberculata (sternberg) jongmaus, Zygopteris sp. (= ? Schizostachys grand'eury), Pecopteris bucklandii brongniart, P. den- sifolia (goeppert) weiss, P. fceminceformis schlotheim ex sterzel, P. hemitelioides brongniart, P. pseudoreopteri- dia potonie emend vetter, P. unita brongniart; Pecop- teris sp., Sphenopteris sp., Alethopteris zeilleri jongmaus, Odontopteris reichiana gutbier (=0. minor-zeilleri Vet- ter), Odontopteris sp., Linopteris brongniartii (gutbier) potonie, Linopteris sp., Autunia conferta (sternberg) kerp (= Callipteris conferta sternberg, brongniart), Dichophyllum flabelliferum (weiss) haubold and kerp (= Callipteris flabellifera weiss), "Callipteris" sp., Hermitia (al. Walchia) sp. Numerous fronds and leaves, some fragments of trunks, and a few fructifications have been recently recovered from the worked section (fig. 3). The leaves, referred to Cordai- tes, are very elongate and show parallel and lengthwise ner- ves. They lie in high density, overlapping each others, and they come from thin dolomitic layers. The stem fragments are assigned to Calamites and they come from a few do- lomitic or bituminous levels. The fructifications, referred to Cardiocarpus sp., are relatively well preserved and come from the siltstones at the bottom of the section. These three taxa represent the only plant remains the precise stratigra- phical origin of which is known. The taxa Autunia conferta, Dichophyllum flabelliferum and some traces attributed to callipterids ("Callipteris sp.") first appeared in the late Stephanian and became dominant in the Autunian. Even if the sphenophyte diversity is very low (the conifers being extremely rare), this macroflora sug- gests a late Stephanian age [sensu Doubinger et al., 1995] rather than an Autunian one. The assemblage is indeed do- minated by Pecopteris and some other typical species such as Alethopteris zeilleri, Odontopteris reichiana, and Linop- teris brongniartii. Unfortunately, we do not know which le- vels, and even which site(s), yielded these taxa. Ostracods They are very numerous in some argillites and bituminous levels (fig. 3). Ostracods from the studied site have not been examined yet. Those from the Souvigny sub-basin were identified [Damotte et al, 1992]; they comprise seven spe- cies sampled at five outcrops : Cypridopsis cf. ovata, Can- dona cf. magnitata, Candona cf. planidorsata, Candona sp., Darwinula cf. hollandi, Darwinula sp., Whipplella carbo- naria. Ostracod assemblages are good palaeoenvironment indicators for both salinity and the rate of organic matter in water. Those from the Buxieres section will probably pro- vide informations on the palaeoecosystem conditions. Insects At present, the entomofauna is restricted to flying insects belonging to the Blattoidea (cockroaches). Only wings have been located in a sequence of siltstone, the so-called "insect horizon" (fig. 3). Surprisingly, specimens of only two fa- milies have been found. These blattoids indicate a lower- most Asselian age. Compsoblattidae Most blattoids from Buxieres belong to this family, possibly to one genus only (Compsoblatta). This form is charac- terized by a dense venation pattern and coloured borders along the wing veins, which appear black in the normal state of preservation (pi. IA). Spiloblattinidae They show a similar coloured wing venation, but the veins are not so densely arranged as in the Compsoblattidae. After the first investigations, two different genera have been iden- tified : Sysciophlebia and possibly Spiloblatta. Elasmobranchs The first elasmobranch reported from Buxieres, a xenacan- thid, was firstly mentioned by Heyler [1984] and described later by Heyler and Poplin [1989] and Poplin and Heyler [1989] as Orthacanthus buxieri. This taxon was based on the anterior part of a skeleton consisting of the neurocra- nium, palatoquadrate, lower jaw, scapulocoracoid, and spine. An isolated spine was also reported. In 1990, Heyler and Poplin gave a new description of the type specimen and of some isolated teeth of characteristic Orthacanthus design. Since that time, hundreds of isolated teeth (one has been figured pi. IB), some isolated spines, and some more or less disarticulated skeletons, all belonging to Orthacan- thus, have been recovered at Buxieres. This Buxieres shark fauna is at present very diversified and it also comprises the first skeleton of Bohemiacanthus from the basin (with tens of isolated teeth from the "insect horizon", fig. 3) and spine fragments of a hybodont shark. Orthacanthidae Orthacanthus (Orthacanthus) buxieri Today, only Orthacanthus (Lebachacanthus) senckenbergia- nus from the Lower "Rotliegend" (Lower Asselian) of the Saar Basin is known as completely preserved skeletons [Heidtke, 1982, 1998]. The subgenus Lebachacanthus dif- fers from the subgenus Orthacanthus especially by the form and articulation of the dorsal spine [Heidtke, 1982, 1998; Soler-Gijon, 1997a]. The dorsal spine of O. (Lebachacan- thus) senckenbergianus is straight, relatively short, 20% of its total length is distally occupied by denticle rows, and it is articulated above the shoulder girdle. The dorsal spine of O. (Orthacanthus) buxieri is slightly curved, 50% of its total length is occupied distally by denticle rows, and it is articulated on the neurocranium. Therefore, O. buxieri be- longs to the typical Orthacanthus up to now known from the Upper Carboniferous, i.e. to the subgenus Orthacanthus Bull. Soc. geol. Fr., 2000, n° 2 244 J.S. STEYER et al. Plate I. - Some fossils from the ?uppermost Carboniferous - Lower Permian of Buxieres-les-Mines, Bourbon-l'Archambault Basin (Allier, France). Scale bar = 1 cm. A. Right blattoid wing, cf. Compsoblatta, Bux 270199(22), coll. Rhinopolis Association, deposed in the Museum national d'Histoire naturelle (MNHN). b. Isolated elasmobranch teeth, Orthacanthus sp., Bux 140998(7), coll. Rhinopolis Association, deposed in the Museum national d'Histoire naturelle (MNHN). C. Progvrolepis heyieri, lateral view of the right maxilla, holotype MNHN BUX 86, coll. MNHN, figured in Poplin, [1999]. Planche I. - Quelques fossiles du ?Carbonifere superieur - Permien inferieur de Buxieres-les-Mines, bassin de Bourbon-l'Archambault (Allier, France). Echelle = 1 cm. A. Aile droite de blatlo'ide, cf. Compsoblatta, Bux 270199(22), coll. Association Rhinopolis, depot au Museum national d'Histoire naturelle (MNHN). b. Dent isolee d'elasmobranche, Orthacanthus sp., Bux 140998(7), coll. Association Rhinopolis, depot au MNHN. C. Progyrolepis heyieri, vue laterale du maxillaire, holotype MNHN BUX 86, coll. MNHN [Poplin, 1999]. Bull. Soc. geol. Fr., 2000, n° 2 AUTUNIAN FLORA AND FAUNA OF BUXIERES-LES-MINES (FRANCE) 245 (Orthacanthus) sensu Heidtke, [1998]. Unfortunately, prac- tically all the species of Carboniferous Orthacanthus are based on isolated spines, teeth and, in the best cases, on some sparse fragments of the neurocranium and shoulder girdle (as is the case for O. bohemiacus). Therefore, the skeletons of this shark from Buxieres will play a very im- portant role in the understanding of the systematics and e- volution of this group. Recently, Soler-Gijon [1997b] described a new species from the (?) Upper Carboniferous of the Puertollano Basin (Spain) as O. meridionalis. The latter species is in fact not so clearly distinct from O. buxie- ri. The differences in the shape of the neurocranium are indeed not very convincing; they depend merely on the state of preservation. Contrary to the opinion of Soler-Gijon [1997c : 161], the features of the spine are very similar. The two species are closely related if not identical. The exceptionally preserved material from Buxieres will proba- bly provide the solution of this problem, and therefore it will afford important informations on the biogeography, dis- persal patterns and evolution of the late Palaeozoic sharks in non-marine biotopes. Xenacanthidae Bohemiacanthus sp. The generally 50 to 100 cm long Bohemiacanthus is mainly characterized by the sculpture pattern of the teeth (size : 1.5-3 mm) and the morphology of the fins [Schneider and Zajic, 1994 : 122-123, figs 21, 22]. The bituminous shale unit located below the ash tuff level named "lien vert" (fig. 3) has yielded some fragmentary skeletons and some dorsal spines [Steyer and Escuillie, 1997] as well as rare isolated teeth. In contrast to this, the "insect horizon" (fig. 3) has produced a mass of isolated teeth but no ske- leton. More commonly, these teeth are in association with Acanthodes remains in another lacustrine bituminous shale horizon of about 40 cm thickness in the sandstone unit at the top of the section (fig. 3). This taxon argues for an As- selian age. Hybodontidae Cf. Lissodus The presence of the hybodont shark Lissodus in Europe has been recently reported from the Stephanian of the Saale Ba- sin [Gebhardt, 1986, 1988], the Stephanian-Asselian of the Saar Basin [Hampe, 1991, 1996], and the Asselian of the North German Basin [Gaitzsch,1995]. Schneider [1986] fi- gured some dorsal spines from the Stephanian of the Saale Basin and referred them with reservation to his new genus Limnoselache, erected for the reception of the species Hybodus vicinalis which is primarily based on teeth and scales. Owing to new discoveries in the Puertollano Basin, Soler-Gijon [1997c] has shown that the teeth and scales of Limnoselache vicinalis are associated with Sphenacanthus- type fin spines. Therefore, the above-mentioned spines fi- gured by Schneider [1986] should belong to Lissodus which is known by isolated teeth from the same level. The Lis- sodus-likc spines from Buxieres are up to 9 cm long and they possess 7 to 11 ridges on the flanks. The number of ridges depends on the size of the spine, i.e. it is related to the ontogenetic stage of the individuals. Some spines pos- sess a central row of hook-like denticles on the posterior side, although further preparation is needed to confirm their presence in all the spines. In addition to the dorsal fin spines, one cephalic spine has been recognized. It is partly embedded in the matrix and shows its lateral face although the lateral extension of the base has been broken. The spine is 5.5 mm long and 5.8 mm high. The main cusp is curved backward and shows no ornamentation. As the base is broken, the presence of accessory cusplets lateral to the main cusp is not possible to demonstrate. One peculiarity of this spine is the posterior lobe of the base which is unusually high. The only cephalic spine with such a high posterior lobe has been described from the Pennsylvanian of Kansas [Maisey, 1982]. Although the dorsal and cephalic spines clearly indicate the presence of an hybodont shark in Buxieres, these fossils do not allow a positive identification at a generic level [Duf- fin, 1985; Maisey, 1987]. Lissodus, according to its distri- bution in the German Basin, is the most likely candidate, but a positive identification would have to wait the disco- very of teeth, so far lacking at Buxieres. We hope that the currently running acid preparation of limy sediments above the black shales in the section will deliver the teeth. Acanthodians They are known in the Buxieres area [Heyler, 1984; Heyler and Poplin, 1990] from isolated spines (curved and laterally flattened), scapulae and scales (squared, smooth and little sized). A subcomplete specimen (including the skull), from the Lower Permian of Bourbon-l'Archambault, has been described by Heyler [1984]. Some acanthodian scapulae are also known in the "Autunian" of Autun [Heyler, 1969]. This whole material has been commonly referred to as Acantho- des sp. This genus is also well known in the "Rotliegend" (Upper Carboniferous-Lower Permian) of central and east- ern Europe [Haubold et al, 1982; Zajic, 1998]. At Buxieres, spines (from fins such as the pectoral ones) are numerous [Steyer and Escuillie, 1997] (fig. 3). Moreo- ver, some sub-complete specimens were recently recovered from the locality; they belong to both juvenile and adult individuals. They will enable specific assignment. Actinopterygians (Palaeoniscoids) The actinopterygian fishes collected until now at Buxieres are mostly disarticulated and represented by a great amount of isolated scales. Small scale areas or a few connected skull bones have been found. Complete fishes are excep- tional and not very well preserved. None of these specimens allows reliable identification at the specific level. The following fishes have been already pointed out [Heyler, 1984; Heyler and Poplin, 1990] : Paramblypterus sp., Aeduella blainvilleil, a small palaeoniscoid with orna- mented bones and scales, and other forms with smooth sca- les. Stamberg [1998] has also noticed some remains reminiscent of Watsonichthys pectinatus. Recently, one other, large, palaeoniscoid was disclosed on the basis of isolated elements : three maxillaries and six mandibles. Their similarities in size (6 to 9 cm long), or- namentation and teeth indicate that they probably belong to the same taxon; moreover, three of them (two mandibles and one maxillary) lie on the same shale slab, suggesting that they come from a single individual. Owing to the size of these elements, this fish could be about 60 to 70 cm long : thus it is among the largest palaeoniscoids known from the Carboniferous and Permian of the Massif central. At first sight, the general shape of the laniaries evoked those of Usclasichthys macrodens from the Permian basin of Lodeve (southern Massif central) [Heyler, 1977]; but a closer examination revealed a different morphology and that this fish is a new species of Progyrolepis, P. heyleri, re- cently erected by Poplin, [1999] (here pi. IC). More com- plete specimens are needed for a better knowledge of this carnivorous fish. Bull. Soc. geol. Fr., 2000, n° 2 246 J.S. STEYER et al. Amphibians The discoveries at Buxieres significantly contribute to the knowledge of the amphibian faunas from the Palaeozoic of France. Such faunas remained rather poorly known until the last few years [Steyer et al., 1998]. These amphibians are represented only by temnospondyls : Archegosauridae [sen- su Boy, 1993], Eryopidae, and Branchiosauridae. These fos- sils are finely preserved; they will allow to discuss the definition and evolution of these families, which are very debated [Milner and Sequeira, 1998]. Moreover, several growth stages are represented; they will afford additional informations about the development of these temnospondyls owing to comparative ontogeny [Boy, 1974, 1990, 1993; Schoch, 1995; Steyer, 2000 a]. Eryopidae Several sub-complete skeletons are assigned to the genus Onchiodon. This is the first report of this genus from the basin of Bourbon 1'Archambault; however it is known in the "Autunian" of the Autun Basin [Werneburg, 1997]. Some fragmentary remains from Buxieres, previously refer- red to as "rachitome" and "probablement Actinodon" [Heyler and Poplin, 1990 : 236], also belong to Onchiodon. The definition and validity of Actinodon were questioned by Milner [1989], Boy [1993], and Werneburg [1997]; in a recent revision of this genus, Werneburg and Steyer [1999a] referred it to the synonymy of Onchiodon. A com- plete postcranial skeleton apparently belongs to a juvenile Onchiodon. Archegosauridae (sensu Boy, 1993) Several skulls and one appendicular skeleton are attributed to Cheliderpeton [Steyer, 1996a]. This is the first report of this genus from France. Cheliderpeton is also well known in the Lower Permian of Czech Republic (C. vranyi) and Germany (C. latirostre). At Buxieres, this genus is repre- sented by a new species which is probably the largest Che- liderpeton one (skull length = 18 cm). Various other fossils belong to juvenile individuals. This exceptionally preserved material will allow to address the problem of the family assignment of Cheliderpeton (Intasuchidae for R.W., or Ar- chegosauridae for J.S.S.), raised during the redescription of the type species (C. vranyi) from Czech Republic (Bohe- mia) [Werneburg and Steyer, 1999b]. Branchiosauridae The Branchiosauridae are the most common Carboniferous- Permian amphibians from France, especially from the Mas- sif central : Autun [Heyler, 1955], Blanzy-Montceau [Heyler, 1980, 1994; Civet, 1983], Lodeve [Heyler, 1969, 1996], and Bourbon-l'Archambault Basins [de Saint-Seine, 1949; Heyler, 1969]. However, branchiosaurids are here re- ported for the first time from Buxieres. Three specimens from the locality are available; two comparatively well preserved skeletons belong to the genus Melanerpeton; one specimen, at least, appears to be refe- rable to M. gracile. According to R.Werneburg, this species is considered as a guide fossil for the biostratigraphic zo- nation of the Upper Carboniferous and Lower Permian, along with the help of some aquatic amphibians in various European regions [Werneburg, 1996]. The Melanerpeton gracile - Discosauriscus pulcherrimus zone is known from many localities in Europe; it belongs to the Upper Asselian. In France, M. cf. gracile may also occur in the Millery For- mation of the Autun Basin [Werneburg, 1996]. If the ref- erence to this species is corroborated by further material, then the biostratigraphic correlation would be ascertained. BIOSTRATIGRAPHIC AND PALAEOENVIRONMENTAL REMARKS The Buxieres section corresponds to a succession of bio- coenoses. We emphasize that it is not our present objective to render a palaeoecological picture of the Buxieres flora and fauna. This would be premature and such an analysis should be made level by level. Biostratigraphy Both blattoid insect wings and isolated shark teeth are among the most useful taxa for biostratigraphical correla- tions between the European Basins [Schneider, 1982, 1985, 1988, 1996; Schneider and Werneburg, 1993; Schneider and Zajic, 1994]. For example, blattoids, which are flying in- sects, have a higher dispersal potential than aquatic or ter- restrial organisms and they can be transported by air currents over long distances. Both blattoids and sharks sug- gest a lowermost Permian (Asselian) age for the studied section. Assuming that the specific identification is right, Melanerpeton gracile supports this age. On the other hand, palynomorphs suggest that the age of the lower beds of the studied section could be transitional between the Stephanian and "'Autunian" [Broutin et al., 1990; Doubinger et al., 1995] or suggest a Stephanian age [Paquette et al., 1980]. Moreover, the "Couche du bas Toit", which has yielded a Stephanian palynological association, is above the "Couche du Toit" which has yielded an "Autunian'VStephanian pa- lynological association. According to Broutin et al. [1990 : 1564], this is a problem of "rejuvenation [i.e. alternation] of floras at the Carboniferous-Permian transition [which] indicates a lateral coexistence of "Stephanian" and "Autu- nian" floras during a variable time scale". This common problem has been firstly raised by Gothan and Gimm [1930]. The coal seams and the ash tuff level named "lien blanc", which have yielded palynomorphs, lie just below the levels which produced insects and xenacanthid fishes of Asselian age. As a result the limit between the Stephanian and the "Autunian" would lie in the lowermost part of the studied section, above the "Couche du bas Toit" and below the first bituminous shale sequence (80 cm above the CBT). There- fore, according to palynomorphs, the limit is in the Supra- Buxieres Member of the Buxieres Formation. But this limit was traditionally [i.e. sensu Debriette, 1992] placed in the lowermost part of this Formation (fig. 2). If possible, during further work, attention should be turned to the lower part of the section. On the other hand, further studies, based on blattoid in- sects and elasmobranch teeth, should improve biostratigra- phical correlations with other Euramerican localities. Branchiosaurs have also been used as stratigraphical mar- kers for several decades, but with methods recently ques- tioned by Steyer [2000 b]. Palaeoenvironment In the lower part of the studied section, the "Couche du Toit" has yielded an admixture of palynomorphs which in- dicates both a coal-swamp and a meso-xerophytic environ- ment. Obviously, at least one of the three palynomorph associations is allochthonous. Since this bed did not pro- duce other fossils, the environment remains unknown. At present, most palaeobiological evidences indicate la- custrine environment for most of the studied section and for the main vertebrates levels. Ostracods [Damotte et al, 1992], elasmobranchs [Schultze, 1985], and adult amphi- bians will probably permit us to address the knowledge of this putative oligohaline and/or hypohaline environment. Bull. Soc. geol. Fr., 2000, n° 2 AUTUNIAN FLORA AND FAUNA OF BUXIERES-LES-MINES (FRANCE) 247 Concerning the large amphibians for example, the assem- blage composed by both the brevirostral Onchiodon and the semirostral Cheliderpeton represents an alligator-like asso- ciation, which does not necessarily reveal a typical lacus- trine environment, as does the gavial-like association. This gavial-like association, mainly composed of longirostral Ar- chegosaurus, Collidosuchus and Platyoposaurus, i.e. highly specialized forms for a fish-eating diet [Steyer, 1996b], rep- resents a typical lacustrine assemblage [Gubin, 1997]. It is not present at Buxieres. But the fact that such a typical lacustrine stegocephalian assemblage is not present at Buxieres does not compulsarily mean that the paleoenvi- ronment is hyperhaline. The elasmobranch fauna of Buxieres is of special interest for the understanding of the evolution of ecosystems in the late Palaeozoic. Schneider and Zajic [1994] have analyzed the diversity of the shark faunas in the Upper Carboniferous and Lower Permian of all basins from the Donetz Basin (Ukraine) to France. They show that, during the Upper Car- boniferous, a remarkable and uniform shark fauna existed in most basins. This fauna consists of Orthacanthus, Bohemiacanthus, Xenacanthus, Lissodus and Sphenacanthus. After the Fran- conian volcano-tectonic event, at the Ghzelian/Asselian transition and, linked to that, after the reorganization of the palaeogeography (i.e., basin configurations and interbasin connections by river systems), in nearly all basins a strong decrease in the diversity of the shark faunas took place. The shark fauna of the Lower Permian lakes consists of Bohemiacanthus and Xenacanthus only. But there is one ex- ception, the Saar Basin where the high diversity persisted up to the top of the lower Permian. The first results at Buxieres show a similar phenomenon in the Bourbon-l'Ar- chambault Basin, that is a remarkably high diversity! But there are interesting differences with the Saar Basin : Or- thacanthus buxieri is closely related to the classical ortha- canths from the Upper Carboniferous of Britain, as O. gibbosuslO. cylindricus, and from the Central Bohemian Basins as O. bohemicus and O. kounovensis. O. senkenber- gianus from the Saar Basin is markedly different from these forms (see above). Very close to the shark fauna of the Bourbon-1'Archambault Basin is that from the Puertollano Basin in Spain reported by Soler-Gijon [1997a,c] and So- ler-Gijon in Schneider et al. [2000]. This fauna consists of Orthacanthus, Sphenacanthus, Lissodus and one form close to Bohemiacanthus or Xenacanthus. Therefore, the Bour- bon-1'Archambault Basin could have formed a link between the Spanish and Bohemian Basins. CONCLUSION Present exhaustive collectings at Buxieres steadily increase our knowledge of the Permian biotas from the French Mas- sif central. Buxieres has yielded diverse flora and fauna : algae, stromatolites, palynomorphs, macroflora, ostracods, insects, elasmobranchs, acanthodians, actinopterygians and amphibians. Most of these taxa indicate lacustrine deposits and an Asselian age, but the lower part of the worked sec- tion might be older (?Stephanian). Today, Buxieres is the only Palaeozoic paleontological site excavated in France. Before the closing of the open coal mine in 2001, further and larger collectings might per- mit to evidence some possible mixture in the available flo- ristic assemblage [Paquette and Feys, 1989; Chateauneuf et al, 1980], to study the dynamics of the fauna and flora connected with the sedimentological context of the basin, and to perform significant biostratigraphical and palaeoe- cological comparisons with the other Laurasian Basins. Acknowledgements. — The authors thank the HBCM for its precious coope- ration, the municipal corporation of Buxieres-les-Mines and the "Conseil General" of the Allier district for their support, and all the excavation teams, both students and permanent workers, for the discoveries. We are also indebted to Michel Martin (Museum d'Histoire naturelle de Boulo- gne/mer, France) for the management of the summer 97 excavations, Da- niel Heyler (Museum national d'Histoire naturelle, Paris), Louis Courel and another anonymous reviewer for their constructive comments on an earlier draft. Thanks to Henri Lavina (MNHN, Paris) and Annie Bussiere (CNRS Dijon) for the figures and to Denis Serrette (MNHN, Paris) for the photos. References Berthoumieu J.-J. (1903). - Flore carbonifere et permienne du Centre de la France. - Auclair Ed., Moulins, 56 p. Bougneres L. (1961). - Le bassin de l'Aumance. - C.R. Acad. Sci., Paris D, 252, 2901-2903. Boy J.A. (1974). - Die Larven der rhachitomen Amphibien (Amphibia : Temnospondyli; Karbon-Trias). - Palaont. Z„ 48 (3/4), 236-268. Boy J.A. (1990). - Uber einige vertreter der Eryopoidea (Amphibia : Tem- nospondyli) aus dem europaischen Rotliegend (?hochtes Karbon - Perm) 3. Onchiodon. - Palaont. Z, 64 (3/4), 107-132. Boy J.A. (1993). - Uber einige vertreter der Eryopoidea (Amphibia : Tem- nospondyli) aus dem europaischen Rotliegend (?hochtes Karbon - Perm) 4. Cheliderpeton latirostre. - Paldontol. Z, 67, 123- 143. Broutin J., Doubinger J., Farjanel G., Freytet P., Kerp H., Langiaux J., Lebreton M.L., Sebban S. & Satta S. (1990). - Le renou- vellement des flores au passage Carbonifere Permien. Approches stratigraphique, biologique, sedimentologique. - C. R. Acad. Sci., Paris, 311, 2, 1563-1569. Chateauneuf J.-J., Feys R., Fuchs Y., Greber C, Hery B. & Lefort J.-J. (1980). - Synthese geologique des principaux bassins per- miens du centre de la France. - Rapport BRGM-DGRST 80 SGN 436 GEO. Civet C. (1983). - Branchiosaurides du bassin houiller de Montceau-les- Mines. - La Physiophile, Soc. et. Sc. Nat. et Hist., 99, 55-74. Courel L., Bonnion S., Gelard J.P. & Paquette Y. (1989). - Le bassin houiller Permien de l'Aumance : bassin intramontagneux en dis- tension sur failles reactivees. In : Dynamique et methodes d'etu- des des bassins sedimentaires (A.S.F. Ed). - Ed. Technip, Paris, 179-185. Damotte R., Lethiers F., Corbin J.C., Renard M. & Debriette P. (1992). - Premieres donnees sur la faune d'ostracodes du Permien in- ferieur de Souvigny (nord du Massif central, France). - Rev. Micropal, 35 (4), 253-270. Debriette P. (1985). - Etude geologique du bassin pcrmo-carbonifere de la Queune (Allier). - Memoire de DER, Dijon, 167 p. Debriette P. (1992). - Le bassin de Bourbon-l'Archambault et le sillon houiller (Allier, France). Presentation et itineraire geologique. - Bull. Soc. Hist. nat. Autun, 144, 13-34. Doubinger J., Vetter P., Langiaux J., Galtier J. & Broutin J. (1995). - La flore fossile du bassin houiller de Saint-Etienne. - Mem. Mus. Nat. Hist. Nat. Paris 164, 1-351. Duffin C.J. (1985) - Revision of the hybodont selachian genus Lissodus Brough (1935). -Palaeontographica, A, 188, 105-152 Escuillie F., Steyer J.-S., Pouillon J.M. & Rage J.C. (1996). - Buxie- res-les-Mines (Allier, France), un important site paleontologique permien (re)exploite en Auvergne : une cooperation Industrie/Pa- leontologie. - "Paleontologie 2000", Deuxieme Congres Natio- nal de Paleontologie, Paris nov. 96, Abstract p.29. Bull. Soc. geol. Fr., 2000, n° 2 248 J.S. STEYER et al. Freytet P. (1997). - Non-marine, Permian to Holocene algae from France and adjacent countries, Part.I. - Ann. Pal. 83 (4), 289-332. Freytet P. (1998). - Non-marine, Permian to Holocene algae from France and adjacent countries, Part.II. - Ann. Pal. 84 (1), 3-51. Freytet P., Lebreton M.L. & Paquette Y. (1992). - The carbonates of the Permian lakes of North Massif Central, France. - Carbonates and Evaporites, 7(2), 122-131. Freytet P., Toutin-Morin N., Broutin J., Debriette P., Durand M., El Wartiti M., Gand G., Kerp H.. Orszag F., Paquette Y., Ron- chi A. & Sarfati j. (1999). - Repartition and paleoecology of non-marine algae and stromatolites : Permian of France and ad- jacent coutries. - Ann. Pal. 85(2), 99-153. Gaitzsch B. (1995). - Griineberg-Formation. In : E. Plein Ed., Stratigra- phie von Deutschland I. Norddeutsches Rotliegendbecken. Ro- tliegend-Monographie Teil II. - Cour. Forsch.-Inst. Senckenberg, 183, 102-106, Frankfurt a.M. Gand G., Garric J. & Lapeyrie J. (1997a). - Biocenoses a Triopsides (Crustacea, Branchiopoda) du Permien du bassin de Lodeve (France). - Geobios, 30 (5), 673-700. Gand G., Lapeyrie J., Garric J., Nel A., Schneider J.W. & Walter H. (1997b). - Decouverte d'arthropodes et de bivalves inedits dans la Permien continental (Lodevois, France). - C.R. Acad. Sci., Paris. 325, 891-898. Gebhardt U. (1986). - Ichthyolithen aus dem Stefan C (Oberkarbon) der Saale-Senke (DDR). - Freiberger Forsch. H., C 410, 65-76. Gebhardt U. (1988). - Taxonomie und Palokologie von Lissodus lacustris n. sp. (Hybodontoidea) aus dem Stefan C (Oberkarbon) der Saalesenke. - Freiberger Forsch.- H., C 419, 38-44. Gothan W. & Gimm O. (1930). - Neuere Beobachtungen und Betrachtun- gen iiber die Flora des Rotliegenden von Thiiringen. - Arbeit. Inst. Palaobotanik Petrographie Brennsteine, 39-74. Gubin Y.M. (1997). - Skull morphology of Archegosaurus decheni Gold- fuss (Amphibia, Temnospondyli) from the early Permian of Ger- many. - Alcheringa, 21(1-2), 104-121. Guillot L. (1958). - Compte-Rendu de la reunion du 26 juin 1958. - Rev. Sc. du Bourbonnais et du Centre de la France, 58, 53-54. Hampe O. (1991).- Erstfunde oberkarbonischer Hybodontierzahne aus dem Saar-Nahe-Gebiet. - Maimer geowissenschaftl. Mitteilungen, 20, 119-130. Hampe O. (1996).- Dermale Skelettelemente von Lissodus (Chondrich- thyes : Hybodontoidea) aus dem Unterperm des Saar-Nahe- Beckens. - Palaont. Z., 70 (1/2), 225-243. Haubold H., Barthel M, Katzung G., Schneider J.W. & Walter H. (1982). - Die Lebenwelt des Rotliegenden. - Neue Brehmbuche- rei, 154. A. Ziemsen Ed., Wittenberg-Lutherstadt, 246 p. Heidtke U.HJ. (1982). - Der Xenacanthidae Orthacanthus senckenber- gianus aus dem pfalzischen Rotliegenden (Unter-Perm). - Mitt. Pollichia, 70, 65-86. Heidtke U.H.J. (1998). - Revision der Gattung Orthacanthus AGASSIZ 1843 (Chondrichthyes : Xenacanthidae). - Palaont. Z., 72(1/2), 135-147. Heyler D. (1955). - Remarques sur les Branchiosaurus de la region d'Au- tun. - C.R. Acad. Sci., Paris D, 240, 997-998. Heyler D. (1969). - Vertebres de l'Autunien de France. - Cahiers de Paleontologie, 166, 1-259. Heyler D. (1977). - Decouvertes ichthyologiques dans le Permien de Lo- deve : une nouvelle structure dentaire. - Geol. Mediterr., 4(3), 189-204. Heyler D. (1980). - Les Vertebres du Stephanien de Montceau-les-Mines (Saone-et-Loire). - Bull. Soc. Hist. Nat. Autun, supplement 1, 94, 53-75. Heyler D. (1984). - Faune fossile du Permien de l'Allier. - Rev. Sc. du Bourbonnais et du Centre de la France, 84, 103-122. Heyler D. (1994). — Les Branchiosaures stephaniens et permiens de Mont- ceau-les-Mines et des autres bassins du Massif Central. In : Co- mite des Travaux Historiques et Scientifiques, Ed., Quand le Massif Central etait sous l'equateur. - CTHS, Paris, 227-247. Heyler D. (1996). - Les vertebres permiens du bassin de Lodeve (He- rault) : bilan. - Bull. Soc. Hist. Nat. Autun, 157, 5-28. Heyler D. & Poplin C. (1989). - Systematics and relationships among the Xenacanthiforms (Pisces, Chondrichthyes) in the light of Carboniferous and Permian French material. - Acta Musei Re- ginaehradecensis S.A., Sc. nat. 22, 69-78. Bull. Soc. geol. Fr., 2000, n° 2 Heyler D. & Poplin C. (1990). - Les Vertebres autuniens de Buxieres- les-Mines (Allier, France). - Bull. Mus. natn. Hist. nat.. 12 (4), 225-239. Launay L. de (1888). - Etude sur le Permien de l'Allier. - Bull. Soc. geol. Fr, (3), xvi, 298-336. Letourneur J. (1953). - Le grand sillon Houiller du Plateau Central fran- cais. - Bull. Sen Carte Geol. Fr., 238(51), 236p. Maisey J.G. (1982). - The anatomy and interrelationships of Mesozoic hybodont sharks. - Am. Mus. Novit., 2724, 1-48. Maisey J.G. (1987) - Cranial anatomy of the Lower Jurassic shark Hybo- dus reticulatus (Chondrichthyes : Elasmobranchii), with com- ments on hybotontid systematics. - Am. Mus. Novit., 2878. 1-39. Mathis V. & Brolhet J. (1990). - Les gisements uraniferes du bassin permien de Bourbon-l'Archambault (Nord du Massif central). - Chr. rech. min. BRGM, 499, 19-30. Milner A.R. (1989). - The relationships of the eryopoid-grade temno- spondyl amphibians from the Permian of Europe. - Acta Musei Reginaehradecensis S.A., Sc. nat., 22, 131-137. Milner A.R. & Sequeira S.E.K. (1998). - A cochleosaurid temnospondyl amphibian from the Middle Pennsylvanian of Linton, Ohio, U.S.A. - Zool. Jour. Linnean Soc, 122, 261-290. Paquette Y. (1980). - Le bassin autunien de l'Aumance (Allier). - These 3e cycle, Univ. de Bourgogne. inedit, 277 p. Paquette Y, Doubinger J. & Courel L. (1980). - Etude palynologique de la couche du toit du bassin autunien de l'Aumance (assise de Buxieres) : liaison avec les milieux se'dimentaires. - Bull. Soc. Hist. Nat. d'Autun, 95, supplement 2, 85-101. Paquette Y. & Feys R. (1989). - Le Bassin de Bourbon-l'Archambault (Aumance) In : J.-J. Chateauneuf and G. Farjanel, Eds., Syn- thase geologique des bassins permiens francais. - Mem. BRGM, Paris, 128, 43-54. Poplin C. & Heyler D. (1989). - Evolution et phylogenie des xenacan- thiformes (=pleuracanthiformes) (Pisces Chondrichthyes). - Ann. de Paleontologie. 75(4), 1-34. Poplin C. (1999) - Un paleoniscoi'de (Pisces, Actinopterygii) de Buxie- res-les-Mines, temoin des affinites fauniques entre Massif Cen- tral et Boheme au passage Carbonifere-Permien. - Geo- diversitas, 21(2), 147-156. Saint-Seine P. de. (1949). - Vertebres autuniens de Bourbon-l'Archam- bault. -Ann. Pal, 35, 133-140. Schneider J.W. (1982). - Entwurf einer biostatigraphischen Zonengliede- rung mittels der Spiloblattinidae (Blattodea, Insecta) fur das kontinentale euramische Permokarbon. - Freiberger Forsch. - H., C375, 27-47. Schneider J.W. (1985). - Elasmobranchier-Zahntypen (Pisces, Chondrich- thyes) und ihre stratigraphische Verbreitung im Karbon und Perm der Saale-Senke (DDR). - Freiberger Forsch.-H., C400, 90-100. Schneider J.W. (1986). - Limnoselache n. gen. - ein Siisswasserhai der palaozoisch-mesozoischen Familie Tristychiidae (Hybodontoi- dea). - Freiberger Forsch.-H., C 410, 77-87. Schneider J.W. (1988). - Grundlagen der Morphologic Taxonomie und Biostratigraphie isolierter Xenacanthodier-Zahne (Elasmobran- chii). - Freiberger Forsch.-H., C419, 71-80. Schneider J.W. (1996). - Xenacanth teeth - a key for taxonomy and bios- tratigraphy. - Modern Geology, 20, 321-340. Schneider J.W., Hampe O. & Soler-Gijon R. (2000). - The Late Carbo- niferous and Permian : Aquatic vertebrate zonation in southern Spain and German Basins. - IGCP 328. Final Report. - Cour. Forsch.-Inst. Senckenberg (in press). Schneider J.W., Rossler R. & Gaitzsch B.G. (1995). - Times lines of the late Variscan volcanism. A holostratigraphic synthesis. - Zbl. Geol. Palaont., 1 (5-6), 477-490. Schneider J.W. & Werneburg R. (1993). - Neue Spiloblattinidae (Insecta, Blattodea) aus dem Oberkarbon und Unterperm von Mitteleuro- pa sowie die Biostratigraphie des Rotliegend. - Verbff. Naturhist. Museum Schleusingen, 7/8, 31-52. Schneider J.W. & Zajic J. (1994). - Xenacanthiden (Pisces, Chondrich- thyes) des mitteleuropaischen Oberkarbon und Perm - Revision der Originale zu Goldfuss 1847, Beyrich 1848, Kner 1867 & Fritsch 1879 - 1890. - Freiberger Forsch.-H., C 452, 101-151. Schoch R.R. (1995). - Heterochrony in the development of the amphibian head, 107-124. In : K.J. McNamara Ed, Evolutionary change and heterochrony. - Wiley, Chichester, Chapter 6. AUTUNIAN FLORA AND FAUNA OF BUXIERES-LES-MINES (FRANCE) 249 Schultze H.R (1985). - Marine to onshore vertebrates in the lower Per- mian of Kansas and their paleoenvironment implications. - The Univ. of Kansas, Paleontological Contributions, 18 p. Soler-Guon R. (1997a). - Orthacanthus meridionalis, a new xenacanth shark (Elasmobranchii) from the Upper Carboniferous of the Puertollano basin. Spain. - N. Jb. Geol. Palaont. Abh.. 204 (2), 141-169. Soler-Gijon R. (1997b). - New discoveries of xenacanth sharks from the late Carboniferous of Spain (Puertollano basin) and early Per- mian of Germany (Saar-Nahe basin) : Implications for the phy- logeny of xenacanthiform and anacanthous sharks. - N. Jb. Geol. Palaont. Abh., 205 (1), 1-31. Soler-Gijon R. (1997c). - Euselachian sharks from the late Carboniferous of the Puertollano basin, Spain : biostratigraphic and palaeoen- vironment implications. - Modern Geology, 21, 137-165. Stamberg S. (1998). - Preliminary results of the study of Permian acti- nopterygian fishes from Buxieres-les-Mines (Allier, France). - Acta Musei Reginaehradecensis S.A., 26, 173-178. Steyer J.-S. (1996a). - Une nouvelle espece de Cheliderpeton (Amphibia, Temnospondyli) du Permien inferieur de Buxieres-les-Mines (Allier, France). Position phyletique et relations ontogenie-phy- logenie des eryopoi'des. - Memoire de DEA, Montpellier, 31p. Steyer J.-S. (1996b). - Readaptation to the aquatic environment and de- velopmental heterochronies in the eryopoi'ds (Amphibia, Tem- nospondyli). - Review of the International Multidisciplinary Congress of Secondary Adaptation to Life in Water, 82-83, Poi- tiers, France. Steyer J.-S. (2000a). - Ontogeny and phylogeny of temnospondyl amphi- bians, a new method of analysis. - Zool. Jour. Linnean Soc. (in press). Bull. Soc. geol. Fr., 2000, n° 2 Steyer J.-S. (2000 b). - Are European Palaeozoic Amphibians good stra- tigraphic markers? - Bull. Soc. geol. Fr., 171, 1 127-135. Steyer J.S. & Escuille F. (1997). - Le chantier de fouilles paleontolo- giques dans le Permien de Buxieres-les-Mines (Allier, France) en aofit 96 : compte-rendu preliminaire et perspectives. - Rev. Sc. Bourbonnais et du Centre de la France, 95, 11-18. Steyer J.S., Gand G. & Pouillon J.M. (1998). - Les Amphibiens du Paleozoi'que et du Trias francais : historique et inventaire. - Bull. Soc. Hist. Nat. d'Autun, 162, 23-40. Turland M., Gentilhomme P., Duthou J.L., Arc D., Carroue J.P., De- BEGLIA N., brosse J.M., DEBRIETTE P., SOSSA-SlMAWANGO (1990). - Carte geologique de la France. Feuille de Montmarault (2528). - Ech. 1/50000, 620 Ed. BRGM. Vetter P. (1984). - Inventaire de la collection pale'ontologique en depot dans les locaux de la municipalite de Buxieres-les-Mines (03). - Unpublished revision, 5p. Werneburg R. (1996). - Temnospondyle Amphibien aus dem Karbon Mittel- Deutschlands. - Verbff. Naturhist. Mus. Schleusingen, 11, 23-64. Werneburg R. (1997). - Der Eryopide Onchiodon (Amphibia) aus dem Rotliegend des Beckens von Autun (Frankreich). - Freiberger Forsch.-H., C466 (4), 167-181. Werneburg R. & Steyer J.S. (1999). - Redescription of the holotype of Actinodon frossardi Gaudry, 1866 from the Lower Permian of the Autun basin (France). - Geobios. 32 (4), 599-607. Werneburg R. and Steyer J.S. (2000). - Redescription of the type species Cheliderpeton vranyi Fritsch 1877 (Amphibia, Temnospondyli) from the Lower Permian of Czech Republic (Bohemia). - Palaont. Z. (in press). Zajic J. (1998). - Acanthodians of the Bohemian Limnic Stephanian. - Czech Geol. Surv. Spe. Papers, 10, 46 p., Prague.