ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011073

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A second species of the genus †Hypsidorisis described from the primitive catfish family †Hypsidoridae. The new species is from Eocene freshwater deposits of the Clamo Formation of central Oregon and is known by numerous well-preserved skeletons. Like the type species from the Green River Formation of Wyoming, the Oregon species has a well-developed toothed maxilla, a feature thought to be primitive among catfishes. Among the more than 35 nominal families containing over 2,200 species of catfishes, only Diplomystidae and †Hypsidoridae have well-developed toothed maxillae. The relationships of †Hypsidoridae to other catfishes are briefly reviewed. The associated ichthyofauna is also briefly discussed in context with other Eocene faunas of western North America.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011074

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new species of fossil catfish, †Nematogenys cuivi(Siluriformes: Nematogenyidae) is described from the Miocene, continental fluviolacustrine deposits of the upper Cura–Mallín Formation (37–39°S), Chile.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011075

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The Ellisdale site (Late Cretaceous, Campanian), Monmouth County, New Jersey, has produced the first representative fossil amphibian specimens from the Cretaceous of eastern North America. The known fauna includes indeterminate pelobatid and discoglossid frogs, an amphiumid (cf.Proamphiumasp.), and a sirenian (cf.Habrosaurussp.), however, the most abundant caudate remains are from a previously undescribed genus of batrachosauroidid salamander, herein described asParrisia neocesariensisgen. et sp. nov.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011076

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Cranial features ofProsalirus bitis, an Early Jurassic anuran from the Kayenta Formation, include a dentigerous premaxilla and maxilla; a parasphenoid with a lanceolate cultriform process and posterolateral alae; a well ossified, unpaired sphenethmoid; and a stapes of modern form. The atlas bears a notochordal fossa between the cotyles. The number of vertebrae is unknown but anterior, middle, and posterior presacrai vertebrae are represented. The sacrum, which lacks postzygapophyses, possesses elongate, narrow alae and a cartilaginous intercentral articulation with a short urostyle. The appendicular skeleton exhibits a relatively primitive glenoid, prolongation of the iliac shaft, elongation of the hind limbs, radio-ulnar and tibiofibular fusion, and unfused, elongate proximal tarsals.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011077

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Numerous isolated and fragmentary remains of a pipid frog from Paleocene-Eocene lacustrine beds of the Vaca Mahuida Formation are described and referred to a new species of the genusShelaniaCasamiquela. A cladistic analysis of fossil and extant pipoid frogs based on 47 osteological characters places the new species in a trichotomy with the South American Paleogene pipidsS. pascualiand“Xenopus” romeri. These three species share a seemingly derived arrangement of perilymphatic and jugular foramina in the occipital region. The species described herein, “X”romeriand, presumably,S. pascualilack discrete superior perilymphatic foramina as in extant African xenopodines; however, they possess several plesiomorphic conditions with respect to the latter. The presence of a pipid lineage distinct to that represented by extant taxa in South America is confirmed by this study.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011078

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Late Triassic strata of the Wolfville Formation in Nova Scotia, Canada, have yielded numerous cranio-dental remains referable to three new taxa of Procolophonidae:Acadiella psalidodon, Haligonia bolodon, andScoloparia glyphanodon. Each taxon is diagnosed by distinctive features of its dentition. Contrary to recent claims, the Procolophonidae are polymorphic with regard to the presence or absence of dermal armor. An adult specimen ofScolopariahas a large nuchal “shield” composed of interdigitating osteoderms. A previous report ofLeptopleuronfrom the Wolfville Formation is based on a juvenile individual ofScoloparia. Scolopariais closely related to, but less derived than,Hypsognathusfrom the Norian of eastern North America andLeptopleuronfrom the Carnian of Scotland. The new procolophonid taxa from the Wolfville Formation greatly increase the recorded diversity of this group during the Late Triassic.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011079

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Three of the six earliest ichthyosaurs, namely,Chaohusaurus geishanensis, Chensaurus chaoxianensis, andChensaurus faciles, occur in the Lower Triassic (Spathian) of the Chaohu area, Anhui Province, China. A reexamination of the three holotypes and two referred specimens indicates that the three species share derived features; however, the characters originally used to distinguish among the three are either growth-related or absent. Measurements of the specimens suggest that they represent a growth series of a single species,Chaohusaurus geishanensisYoung and Dong 1972. The forefin of this species shows a strongly positive allometry, leading to the unusually large forefin in the largest specimen (the holotype). The use of the standard allometric equation may be problematic when two structures compared start their developments asynchronically. However, the alternative equation of Schmalhausen is also problematic, and therefore more scrutiny is required. The lunate fin elements, which commonly occur in the first and fifth digits of Early Triassic ichthyosaurs, first become ossified as biconcave elements, as in other metacarpals and phalanges.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011080

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The holotype and only known specimen ofShingyisaurus unexpectusYoung, 1965, from the Middle Triassic (Anisian) of China is redescribed. Originally identified as a simosaur, the incomplete and poorly preserved skull is instead referable to the genusNothosaurus. Consequently, simosaurs remain unknown from the western Pacific faunal province. The occurrence ofNothosaurusin the Anisian of China provides circumstantial evidence for Asiatic affinities of the Nothosauridae.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011081

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Hanosaurus hupehensiswas believed to represent a Middle Triassic thalattosaur from the People's Republic of China. Redescription of the holotype and only known specimen, and cladistic analysis of its interrelationships, showsHanosaurusto represent a distinct pachypleurosaur. The two Chinese pachypleurosaurs,KeichousaurusandHanosaurus, form two consecutive sister-groups to European pachypleurosaurs, strengthening the Asiatic affinities of the clade. Addition ofHanosaurusfurthermore results in a modification of pachypleurosaur interrelationships as previously reconstructed: the pachypleurosaurs from the Germanic Triassic(Anarosaurus, Dactylosaurus)form a monophyletic clade, which is sister-group to the monophyletic clade of Alpine pachypleurosaurs(Serpianosaurus, Neusticosaurus). Thalattosauria are the sister-group of Sauropterygia, the two clades possibly representing a single invasion of the Mesozoic sea. However, more detailed knowledge of thalattosaur anatomy is required to further test the phylogenetic relationships of thalattosaurs.

ISSN:0272-4634    

DOI:10.1080/02724634.1998.10011082

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor