摘要:

The skull of the ‘Rhaeto‐Liassic’ mammalSinoconodon changchiawaensis(Young) from the lower Lufeng Series of China is described. It is characterized by a relatively larger and more robust dentary condyle and a greater reduction of the post‐dentary bones than are present in the Morganucodontidae, Kuehneotheriidae, andDinnetherium.In other aspectsSinoconodonis more primitive; precise post‐canine occlusion is lacking, the mandibular symphysis is deep, the jaw articulation lies below a line projected through the apices of the teeth, the pterygoparoccipital foramen is large and the post‐canine teeth cannot be divided into molars and premolars. The jaw articulation and braincase ofSinoconodonare compared with those of the two cynodont therapsidsProbainognathusandThrinaxodon.It is concluded that in the transition from therapsid to mammal the medial surface of the groove in the squamosal housing the quadrate was lost and, as a result, inSinoconodon, MorganucodonandDinnetheriumthe hollow medial surface of the quadrate abutted directly against the paroccipital process. A definition for the Class Mammalia is given. It is suggested that the three‐boned middle ear was present in Cretaceous triconodonts, and that it probably arose independently in the lines leading to multituberculates and Cretaceous therians. The structure of recently discovered ‘Rhaeto‐Liassic’ mammals and that ofSinoconodonindicates that there was greater diversity among the earliest known mammals than was

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1985.tb01500.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The three important species of large, scaled sea‐turtles still retain their Linnaean specific names:Chelone mydas, Caretta caretta,andEretmochelys imbricata.Linnaeus demonstrated in his writing inSystema Naturae,particularly in some references to other authors, that he grasped the essence of the three concepts. The morphological characterization of these animals were poorly developed at that time and Linnaeus documented the concepts stated by himself in an ambiguous way. The currently recognizedChelone mydasis shown to be a collective concept inSystema Naturae,because the descriptions by Linnaeus and the still extant type specimens prove that the currentCaretta carettais included in it. The consequences for nomenclature of these taxa are discussed and the extent and status of Linnaean zoological specimens kept in Sweden is reviewed.SUMMARYLinnaeus (1758) describedTestudo mydas(presentChelone mydas)mainly on four of his own earlier descriptions. Type specimens of three of these exist. A specimen belonging to the fourth description cannot be accepted as a type due to discrepancies between its appearance and details noted by Linnaeus (1745). The specimen is identifiable as the presentCaretta carettaalthough the description (Linnaeus, 1745;mydasβ) points to the currentChelone mydas.However, two of the other earlier descriptions (Linnaeus, 1745:mydasβ 1746) point indisputably toCaretta caretta.The extant types are also identifiable asC. caretta.The remaining description (Linnaeus, 1754) can be accepted as pertaining to the currentChelone mydasand the type specimens of it are kept in the Stockholm collection. They are identifiable asC. mydasand one of them should be designated neotype ofTestudo mydasLinnaeus, 1758, in a revisionary work stabilizing nomenclature with conservation of the Linnaean species name.Testudo carettaLinnaeus, 1758 (presentCaretta caretta)has no surviving type material neither hasT. imbricataLinnaeus, 1766 (presentEretmochelys imbricata).AsC. carettais shown to be included in the Linnaean conceptTestudo mydas,and as it was placed behindT. mydasin Linnaeus (1758), its Linnaean species name is not available. Its citation should beTestudo carettaWalbaum, 1

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1985.tb01501.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Species of the genusParadoxostomaFischer are an important component of marine and estuarine ostracod faunas throughout the world. This revision of the genus in British waters deals with 17 species of which six are described as new. Each species is diagnosed and illustrated in detail, and comments are made on their ecology and distribution. The specialized mouthparts which characterize the genus are illustrated by means of the scanning electron microscope for the first time. A key to the genus is given.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1985.tb01502.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY