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1.
In the Majastre area (Alpes-de-Haute-Provence, South-Eastern France), the hemipelagic domain of the Lower Cretaceous is exposed to the favour of the “Décrochement du Poil”. This palaeogeographical and paleotectonic position allowed the harvest of a diversified ammonite-fauna in the level with “small Barremites”. It is precisely dated here for the first time, and takes place between the base of the Barremense subzone and the base the Breistrofferi biohorizon of the Vandenheckei biozone (base of the Upper Barremian). Within this fauna, Artareites landii nov. sp. is considered here as a possible descendant of the genus Dissimilites Sarkar due to its characteristics and stratigraphic position. The genus Artareites nov. gen. is certainly an important milestone of the Helicancylidae towards the Toxoceratoides genus morphology. In this case, in agreement with the morphological, ontogenical, stratigraphical and paleobiogeographical parameters, some North American species could be considered as potential intermediate. Due to their characteristics and their joint origin, genus of small size included in the Helicancylidae represent a coherent set with the rank of a family, and is independent of the Ancyloceratidae. Its content is revised and limited to the genus phyletically associated around the main axis of Acrioceras-Dissimilites-Artareites nov. gen. and Toxoceratoides-Helicancylus, whose elements are connected by a number of forms. In this case, Monodites nov. gen. is created for the Hauterivian and Lower Barremian very specific forms Monodites crevolai (Vermeulen et al.) and Monodites trumpyi (Kakabadze et Thieuloy) which does not seem to be integrated in the taxa already recognized in the literature. The family Monoditidae nov. fam. is proposed to mark this uniqueness.  相似文献   

2.
Bouleiceras is a very rare genus among the rich assemblages of ammonoids from the lower Toarcian of the Iberian Range. So far, only two dozen specimens have been recorded in numerous field campaigns carried out since 1965 by different authors. The interest of this taxon lies in its peculiar paleogeographical distribution in comparison with most other ammonoids of the same age. A review of these specimens is carried out, including those obtained in previous works and others recently collected in selected localities. Based mainly on the differences in the shape of the ventral section and the suture line, seven species have been identified; two of which are new: Bouleiceras ibericum nov. sp. and Bouleiceras? betetensis nov. sp. All the reviewed specimens are recorded in the Semicelatum Subzone of the Tenuicostatum Zone and the Elegantulum Subzone of the Serpentinum Zone from the Central Sector and the Levantine Sector of the Iberian Range. The global distribution of the genus is summarized from the known data, and its possible dispersal routes are analyzed, as well as the factors that could have conditioned them.  相似文献   

3.
A new genus Pseudoancyloceras gen. nov. with the type species P. calinovense sp. nov. and five new species of Ancyloceratidae (Australiceras (Proaustraliceras) elegans sp. nov., Audouliceras vyrystaykense sp. nov., A. brusyankense sp. nov., A. mordovense sp. nov., Tropaeum (Tropaeum) elaurkense sp. nov.) are described from the Aptian of the Ulyanovsk region, Middle Volga.  相似文献   

4.
A new genus and two new species of ducks (Aves: Anatidae) from the Middle Miocene Sharga locality are described. Mioquerquedula minutissima gen. et sp. nov. is a very small duck. Anas velox Milne-Edwards, 1868 from the Middle Miocene of France is transferred to the genus Mioquerquedula. Aix praeclara sp. nov. described here is the oldest record of the modern genus Aix. A revision of the previously described small duck Anas soporata Kurochkin, 1976 shows that only the specimens from the Sharga locality should be referred to this species. The status of other small ducks from the Neogene of Europe and North America is discussed. The diversity of herbivorous and diving ducks in the Sharga locality indicates that Miocene Shargyn Govi Lake was rich in food resources.  相似文献   

5.
《Palaeoworld》2014,23(3-4):252-257
Platycrinites was long a “catch-all” genus that was loosely defined in North America. Ausich and Kammer (2009) rectified the inconsistencies of generic diagnoses to define the Platycrinitidae better; however, due to preservation, many species were not known from specimens with sufficient characters to be placed confidently into a genus and, thus, were designated Platycrinites sensu lato. Collicrinus excavates (n. comb.) was one such species. A specimen with a complete theca and partial arms preserved was discovered in southwestern Missouri in the Burlington–Keokuk Limestone. With the discovery of this specimen, C. excavatus has been fully described and placed in the correct genus. Further, the associated fauna of new C. excavatus specimens, reported here, helps to evaluate the stratigraphic position of this species, which is now considered to be only from Burlington Pelmatozoan Association I and II, roughly equivalent to the Dolbee Creek and Haight Creek Members of the Burlington Limestone.  相似文献   

6.
In 1909, the famous paleontologist Louis Dollo identified two putative new species of giant soft-shelled turtles from the lowest Eocene record of Belgium, ‘Trionyx erquelinnensis’ and ‘Trionyx levalensis’, from Erquelinnes and Leval, respectively. However, these proposals did not meet the requirements of the International Code of Zoological Nomenclature, so they were considered as nomina nuda. The information on these specimens or about any other specimen of this lineage of giant turtles from the Belgian record is currently extremely limited. Relatively scarce material from giant trionychids has been described for the lower Eocene record of other European regions. Considering the available information, all the European material has recently been recognized as belonging to the genus Axestemys, which has a North American origin, and possibly attributable to a single species, Axestemys vittata, which currently lacks a diagnosis. Numerous and well-preserved Belgian specimens are deposited in the Royal Belgian Institute of Natural Sciences. In addition to the cited individuals from Erquelinnes and Leval, additional specimens from both localities, as well as others from Orp-le-Grand, are part of this collection. These specimens, found between the decades of 1910 and 1930, have been recently restored, and their study is carried out here. The presence of Axestemys vittata in Belgium (in Leval and Orp-le-Grand) is confirmed. Knowledge about this species is significantly improved, and a diagnosis is proposed. However, the hypothesis proposed by Dollo is here confirmed, this species being not the only identified in the Belgian record. So, Axestemys erquelinnensis nov. sp. is defined based on the carapace from Erquelinnes known by Dollo, suggesting that the genus probably reached Europe during the Paleocene Eocene Thermal Maximum.  相似文献   

7.
This work is mainly an answer to the work of Bert (2009), on families Helicancylidae Hyatt, 1894 and Acrioceratidae Vermeulen, 2009. On the nomenclatural speaking, the non validity of the genus Helicancylus Gabb, 1869 and of the family Helicancylidae Hyatt, 1894 and, consequently, the validity of the family Acrioceratidae Vermeulen, 2004 are established. The second part of this work is devoted to the respect of former work and, contrary to the assertions from Bert (2009), it is shown that the stratigraphical positioning of the Upper Barremian level with small Barremites, realized by Cotillon (1971), is at least as precise as that proposed by Bert. The last part of this work highlights a lack of bibliographical references, fact which had already been highlighted ( Vermeulen and Lepinay, 2010) in a former work of Bert et al. (2009).  相似文献   

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9.
The stratigraphic and paleogeographic ranges of Ordovician bryozoans of the genus Diplotrypa (Trepostomida: Halloporidae) are analyzed. It is shown that they were then limited in geographic range to the Paleobaltic Basin (the most probable center of origin of the genus Diplotrypa) and to the West Arctic and North American basins. The Silurian bryozoans of this genus were represented by only a few species. In addition, the intercolonial variability of the species Diplotrypa abnormis (Modzalevskaya, 1953) and D. petropolitana (Nicholson, 1879) is studied; Upper Ordovician specimens of these species have been discovered from the Leningrad Region of Russia for the first time. The colonies of these species from the Leningrad Region are compared here with those of Podolia (Western Ukraine) and Vaygach Island (western sector of the Russian Arctic).  相似文献   

10.
Several isolated cheek teeth and mandibular specimens of Rhinocerotidae (Mammalia, Perissodactyla) from the upper Miocene Namurungule Formation in Samburu Hills, Kenya, are redescribed. Previously, these specimens had been identified as Chilotheridium pattersoni, Chilotheridium sp., Paradiceros mukirii, and Paradiceros sp. They are reidentified here as documenting the genus Brachypotherium based on their bucco-lingually broad molariform upper premolars with short crochet and flattened buccal walls on both upper and lower molars, the latter having a shallow external groove. Comparisons with other Brachypotherium species suggest that the present specimens belong to Brachypotherium sp. cf. B. minor. The presence of Brachypotherium in the Samburu Hills, at ca. 9.5 Ma, is concordant with the paleoenvironment (presence of lacustrine and river environments) known for this locality during the early late Miocene.  相似文献   

11.
Anaporrhutine gorgoderids (Digenea: Gorgoderidae: Anaporrhutinae) found in the body cavity of six species of elasmobranchs from the orders Carcharhiniformes, Myliobatiformes and Orectolobiformes from Australian waters were found to belong to the genus Staphylorchis. Although these specimens were morphologically variable, sequences of ITS2 and 28S ribosomal DNA from specimens from three host families and two host orders were identical. Based on morphological and molecular data these specimens were identified as the type-species of the genus, Staphylorchis cymatodes. New measurements are provided for S. cymatodes, and for the first time genetic data are presented for this species. In addition to providing new morphological and molecular data for S. cymatodes, the previously described species S. gigas, S. parisi and S. scoliodonii, are here synonymised with S. cymatodes. This implies that S. cymatodes, as conceived here, has remarkably low host-specificity, being recorded from eight elasmobranch species from four families and three orders, has a wide geographical distribution in the Indo-west Pacific from off India, in the Bay of Bengal, to Moreton Bay in the Coral Sea, and is morphologically plastic, with body size, size of specific organs and body shape differing dramatically between specimens from different host species. The genus Staphylorchis now contains only two valid species, S. cymatodes and S. pacifica.  相似文献   

12.
The deposits of the Carnian Kas?mlar Formation within the Taurus Platform Units of south‐western Turkey represent an important archive of a Late Triassic ecosystem. New palaeontological information was obtained by analysing the Kasimlarceltites mass occurrence, located within the Kas?mlar Formation and named after the Lower Carnian (Julian) ammonoid genus Kasimlarceltites. This is the dominant taxon (> 94%) within the mass occurrence: nearly 775 million ammonoids and 50 million gastropods were extrapolated for the whole extension (at least 5 km2) of the Kasimlarceltites beds. This calculation is one of the main findings within this study, as it is the first time that such a fossil mass occurrence was quantified. Additionally, orientation measurements of the planispiral ammonoids and the helical gastropods enabled reconstructing the history of the mass occurrence and interpreting the underlying transport mechanisms. Further taphonomic aspects (e.g. biofabric, preservation, bioerosion or genetic classification) as well as comparisons with samples of the same acme zone from different localities near A?a?iyaylabel (AS IV, KA I‐II) point to a two‐phased genetic history. Accordingly, local mass mortality within the Kasimlarceltites fauna due to oxygen fluctuations or methane degassing may have initially led to a primary accumulation. These deposits were then reworked and redeposited basinward by gravity flows to create the present‐day secondary allochthonous concentrations.  相似文献   

13.
A new genus Siberioklipsteinia (with the type species S. dagysi sp. nov.) and a new species Arctoarpadites nelgesensis are described from the Carnian of the Kharaulakh Range and Yana Upland (eastern Yakutia). The new data allow refinement of the taxonomy of Carnian ammonoids of northeastern Asia and emendation of some details of their geographical differentiation. The new ammonoid taxa belong to the family Arpaditidae, which was not previously recorded from the eastern Boreal Realm.  相似文献   

14.
In North Africa, the ammonoids constitute an important part of the Devonian marine macro-invertebrates. New material has been recently collected in the ‘Argiles de Marhouma’ Formation from several sections located near Béni-Abbès in the Saoura Valley (Ougarta Mountains, Algerian Sahara). Red nodular limestones (i.e., ‘griotte’ facies) characterize this formation rich in ammonoids. The assemblages from the Ouarourout section are composed of Goniatitida and Clymeniida constituting 30 species and 19 genera belonging to 11 families, with Cyrtoclymenia, Erfoudites, Kosmoclymenia, Planitornoceras, Platyclymenia, and Prionoceras, as the most abundant genera. The taxonomic comparison and the biostratigraphic correlations are made by considering the assemblages recorded in the Anti-Atlas of Morocco, which are very close to those observed in Algeria. In the Ouarourout area, the ‘Argiles de Marhouma’ Formation contains middle and late Famennian ammonoid assemblages and three biostratigraphic intervals can be identified: Planitornoceras, Platyclymenia and Medioclymenia.  相似文献   

15.
A multi-locus phylogenetic study of the order Arthoniales is presented here using the nuclear ribosomal large subunit (nuLSU), the second largest subunit of RNA polymerase II (RPB2) and the mitochondrial ribosomal small subunit (mtSSU). These genes were sequenced from 43 specimens or culture isolates representing 33 species from this order, 16 of which were from the second largest genus, Opegrapha. With the inclusion of sequences from GenBank, ten genera and 35 species are included in this study, representing about 18 % of the genera and ca 3 % of the species of this order. Our study revealed the homoplastic nature of morphological characters traditionally used to circumscribe genera within the Arthoniales, such as exciple carbonization and ascomatal structure. The genus Opegrapha appears polyphyletic, species of that genus being nested in all the major clades identified within Arthoniales. The transfer of O. atra and O. calcarea to the genus Arthonia will allow this genus and family Arthoniaceae to be recognized as monophyletic. The genus Enterographa was also found to be polyphyletic. Therefore, the following new combinations are needed: Arthonia calcarea (basionym: O. calcarea), and O. anguinella (basionym: Stigmatidium anguinellum); and the use of the names A. atra and Enterographa zonata are proposed here. The simultaneous use of a mitochondrial gene and two nuclear genes led to the detection of what seems to be a case of introgression of a mitochondrion from one species to another (mitochondrion capture; cytoplasmic gene flow) resulting from hybridization.  相似文献   

16.
In the present work, we examine a sample of 54 specimens of the heteromorph ammonite genus Ancyloceras d’Orbigny, 1842 from the Argiles à Plicatules Formation (lower Aptian, Lower Cretaceous) of the eastern Paris Basin (NE France). The results are as follows: (1) the sample is regarded as monospecific and assigned to the well-named species Ancyloceras varians d’Orbigny, 1842; (2) its variability is continuous and concerns as well as adult size, coiling and shell ornamentation. Adult size varies by a factor of two from one individual to another. The angle between the proversum and the retroversum is variable. The ornamentation on the spiral and the proversum varies between robust morphotype with trituberculate strong ribs separated by few smooth intercalaries ribs and slender morphotype with feebly tuberculate ribs. There are no arguments in favor of sexual dimorphism in Ancyloceras varians.  相似文献   

17.
The different forms of the aptychi (opercula, homologous with lower jaws) of the Ammonoidea are used for the first time in a phylogenetic analysis of part of the classic Ammonoidea phylogeny. The results indicate that the aptychi-possessing ammonoids form a monophylum for which we propose the informal name Aptychophora nov. Among the Jurassic ammonoids, it is possible to recognize several monophyletic groups. In part, our results support existing superfamilies (e.g. Hildocerataceae, Haplocerataceae) by new synapomorphies. However, the Perisphinctaceae can now be much more clearly differentiated than in the previously established phylogenetic tree. The Upper Cretaceous ammonoid superfamilies cannot be derived from the Haplocerataceae, but are descendants of a 'primitive' perisphinctacean possessing a praestriaptychus. Nor can they be derived from the 'higher' perisphinctaceans (family Perisphinctidae) because that clade is characterized by granulaptychi. The consequence of these results is that the quadrilobate primary suture of the 'Ancyloceratina' must have evolved more than once by reduction from an ancestral quinquelobate primary suture. The Ancyloceratidae have praestraptychi or aptychi types which can be derived from praestriaptychi, whereas the Crioceratitinae have longitudinally striated anaptychi.  相似文献   

18.
Eudromoxyura aspiculuris (Boero &; Led, 1971) is a parasite of a tinamid bird in Argentina. This is the type and only one known speices so far described in the genus Eudromoxyura Anderson &; Prestwood, 1972. It is here redescribed, and Eudromoxyura elonbyrdi Anderson &; Prestwood 1972 is considered a synonym. The morphological characters and systematic position of the genus Eudromoxyura are discussed. The genera Syphaciella (Mönning, 1920) and Eudromoxyura, the only oxyurids known parasitising birds, have probably arisen independently.  相似文献   

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