摘要:

A Late Ordovician (late Caradoc) linguliformean microbrachiopod assemblage from north-central Kazakhstan contains 12 taxa of acrotretides, lingulides and paterinides including two new genera:Atansoria(type speciesAtansoria concavasp. nov.) andNaimania(type speciesIsedonia proceraPopov, 1980) plus the new speciesConotreta? chernovi. It also provides a first record of the presence ofDictyonites, Foveola, AcrotretaandEphippelasmain the Caradoc, andAcrotretellais reported for the first time outside Baltoscandia in the Ordovician. The assemblage retains some distinctive characters of microbrachiopod faunas known from the late Arenig and Llanvirn of central Kazakhstanian terranes, and is clearly distinct from the Llandeilo and early Ashgill assemblages of the Chingiz-Tarbagatay terrane (east Kazakhstan). The latter demonstrate more similarity to the Baltoscandian faunas.

ISSN:0311-5518    

DOI:10.1080/03115510008619531

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A skull of a young specimen ofDipnorhynchus sussmilchi(Etheridge Jr), from the base of the Bloomfield Limestone Member (mid-Emsian, probablyperbonusZone) at Taemas, has both sides of the skull roof preserved, but the cheeks are missing. The posterior end of the endocranium, up to its dorsal extremity, provides new data on the endolymphatic sacs, and the attachment of the epaxial muscles. The endolymphatic region is compared with that ofChirodipterus australis. The palate is not fully formed and the marginal ridges are not fully developed. The fine structures around the dermopalatines and the pterygoids are preserved, indicating the manner in which the plates grew. The position of the parasphenoid is clearly outlined against the pterygoids, and confirms the view that this primitive genus of dipnoans did not have the pterygoids divided by the parasphenoid. All these features provide new information and comparison withDipterus valenciennesi, the next oldest genus on which the same regions are preserved. In addition, a new mandible from a horizon low in the Cavan Bluff Formation is well preserved and provides information on the external bones ofDipnorhynchus.

ISSN:0311-5518    

DOI:10.1080/03115510008619532

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A newly discovered partial skull of a temnospondyl from the Early Triassic Blina Shale of the Erskine Range, Western Australia, is referred to the mastodonsaurid speciesWatsonisuchus aliciae. A partial skull described as ‘Parotosuchus’ sp. by Warren (1980) is also referred toW. aliciae. Both taxonomic assignments should be treated with caution because of the relatively poor state of preservation of the specimens.W. aliciaeis the fourth temnospondyl species to be described from the Blina Shale. The worldwide distribution of mastodonsauroids at the base of the Triassic suggests a rapid phase of radiation and dispersal following the Permo-Triassic extinction event.

ISSN:0311-5518    

DOI:10.1080/03115510008619533

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Cetricycas antarcticusgen. et sp. nov. occurs in the Late Coniacian to Campanian Lachman Crags Member of the Santa Marta Formation, Marambio Group, James Ross Island, Antarctica. The petrified trunk comprises a thick pith containing thin and thick walled parenchymous cells, vascular traces surrounded by a thin layer of loose secondary wood. Medullary bundles arise inside the wood zone and pass outwards through multiseriate medullary rays. The trunk anatomy indicates assignment to the Cycadales, and the presence of medullary bundles indicates the affinities with a clade comprisingLepidozamia, Macrozamia, andEncephalartos. This clade is presently confined to Australia and Africa, but fossil representatives extend the geographic range to India, South America and now Antarctica.

ISSN:0311-5518    

DOI:10.1080/03115510008619534

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A new genus and species of dasyurid is described on the basis of P3, M1–M3and M2–3collected from the middle Pliocene Chinchilla Local Fauna of south-eastern Queensland. Character analysis supports the placement of this new taxon within the dasyurid subfamily Dasyurinae. Derived dasyuromorphian features common toA. chinchillaensisand most dasyurines include: reduction of P3, reduction of stylar cusp B on M1; reduction of metaconids; approximation of stylar cusp B and the metacone on M1; alignment of the postmetacrista on M1with the long axis of the maxilla and an oblique orientation of the hypocristids with respect to the long axis of the teeth. However in most instances,A. chinchillaensisis less specialised than other members of the subfamily for characters considered. One derived dental feature, reduction of the entoconid, may indicate a special relationship with ‘parantechinines’,Dasyuroidesand/orDasycercus. Additionally, the presence of this feature is suggestive of an open woodland/seasonal habitat. Autapomorphic P3morphology compounds difficulties with the phylogenetic placement of this taxon.

ISSN:0311-5518    

DOI:10.1080/03115510008619535

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor