摘要:

New material of the Early Devonian placodermBuchanosteus confertitubercutatus(Chapman) is described, and a revised diagnosis is presented. The new material permits a detailed account of endocranial morphology; a canal for the orbital artery is identified for the first time, the courses of the efferent pseudobranchial and ophthalmica magna arteries are reinterpreted, and new information is presented on the structure of the palatoquadrate and parasphenoid. The presence of an eyestalk is established. Interrelationships of euarthrodiran taxa are briefly discussed;Buchanosteusis referred to the suborder Brachythoraci, which is redefined on the structure ofthecheek and elongation of the submarginal plate. Other phylogenetically significant characters for brachythoracid taxa are considered to be the reduction of the trunk‐shield and the shape of central and preorbital plates in the skull‐roof. Revised diagnoses are presented for the order Euarthrodira, suborder Brachythoraci, infraorder Phlyctaenioidei and family Buchanosteidae.Parabuchanosteus murrumbidgeensis(White) is considered synonymous withBuchanosteus con/eftitubercula

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01912.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Five species of the genusPhyllodocefrom Southern California are reviewed. A new subgenus(Aponaitides)is proposed and a new species,Phyllodoce cuspidata, is described. A key to the Southern California species is included.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01913.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Cladistic methodology is used to test the hypothesis that three major monophyletic groups exist among living mammals–the oviparous monotremes (Prototheria), and the viviparous marsupials (Metatheria) and placentals (Eutheria). Evaluation is made of the polarity (i.e. the direction of change in a primitive‐to‐derived sequence) of numerous characters which distinguish some or all of these groups, and of the usefulness of these characters in phylogenetic inference. An attempt is made to establish the state of these characters in the common Late Jurassic‐Early Cretaceous therian ancestor of marsupials and placentals.It is concluded that the most basic division of the Mammalia is the dichotomy into the subclasses Prototheria (including Monotremata, Multituberculata, Triconodonta, Docodonta) and Theria (including Metatheria, Eutheria, Pantotheria and Symmetrodonta). Two major groups exist among living viviparous mammals, the Metatheria and Eutheria; in a cladistic framework these are sister‐groups. It is demonstrated that there is no special (sister‐group) relationship between monotremes and marsupials, and there is no justification for placing them in a group

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01914.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

In lizards, a short Vidian canal pierces the base of the basipterygoid process. In snakes, the anterior opening of the primitively short Vidian canal lies on the dorsal surface of the basisphenoid, trapped in an intracranial position by downgrowths of the frontal and parietal which meet the lateral edges of the basisphenoid‐parasphenoid complex. This condition is observed in anilioid snakes which retain other primitive features in the braincase: the paroccipital process and the spheno‐occipital tubercle (Aniliidae only) and participation of the basioccipital in the apertura lateralis of the recessus scalae tympani.Subsequent evolution within booid snakes shows a shift of the anterior opening of the Vidian canal around the anterior edge of the basisphenoid, thus acquiring a secondary extracranial position. This occurs in parallel within boine and pythonine snakes.Dinilysiashows a parallel development of die condition observed in advanced booid snakes.Pseudoboa, with its short Vidian canal opening in‐tracranially, demonstrates that caenophidians originated from a basal henophidian or pre‐henophidian stock. The Acrochordidae show a basicranium that can be interpreted as either primitive henophidian or primitive caeno

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1979.tb01915.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY