摘要:

The head ofAnomochilus webericombines features seen in living uropeltines and scolecophidians, two clades of fossorial snakes that appear to have the most specialized and, at the same time, the most divergent modifications of the head. However, the weakly supported premaxilla ofAnomochilusdeparts from both scolecophidian and uropeltine modes of reinforcing the anterior tip of the snout, suggesting thatAnomochilusis a less specialized burrower. Its skull also has a number of features unusual among snakes, including a unique buttress on the anterior ends of the septomaxillae, an ectopterygoid reduced to a splint that touches neither maxilla nor pterygoid, a short maxillary tooth row oriented at 45° to the long axis of the skull, and a braincase and snout complex that are uniformly wide. The features of the upper jaw are predicted to confer behavioural and mechanical attributes intermediate between those of typhlopid scolecophidians and uropeltines

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb02535.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Phylogenetic analysis of 38 skeletal characters, 12 muscular characters and 15 visceral characters in 17 major snake clades plusAnomochilussuggests thatAnomochilusis the sister taxon of all other living alethinophidian snakes. However, skeletal, muscular and visceral character sets analysed separately or in pairs give four groups of nonconcordant tree topologies. Based on the cladogram derived from the total evidence, two families are erected to prevent the existing family Uropeltidae from becoming paraphyletic: Anomochilidae, for the Malaysian and Indonesian genusAnomochilus, and Cylindrophiidae, for the Sri Lankan, Southeast Asian and Indonesian genusCylindrophisand the Upper Eocene fossilEoanilius.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb02536.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Patterns of ossification are described in the endo‐and exoskeleton ofAlligator mississippiensis.The occurrence of a dermo‐supraoccipital is discussed in light of the independence of dermal and endochondral bone. The development of the bony secondary palate is discussed in light of Haeckelian recapitulation. The sequence of ossification in the limb skeleton is shown to differ from the sequence of chondrification of the cartilaginous precursors. Patterns of ossification inAlligatorare compared to lepidosaurs in terms of sequence and timing. Important differences relate to ossification patterns in the limb skeleton: lepidosaurs show a dominance of digit III>IV>II>I>V, whereas Alligator shows a dominance of digits III>II>IV>I>V in the ossification process. Ontogenetic repatterning in the ossification of the axial skeleton is discussed as it bears on the serial homology of dorsal ribs, sacral ribs and caudal ribs (transverse process

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb02537.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Five species of tardigrades were extracted from a sample of sediment from a rain gutter. Four of these, the heterotardigradeEchiniscus testudoand the eutardigradesMilnesium tardigradum, Ramazzottius oberhaeuseri, and probablyMacrobiotuscf.sandraeare typical of xerophilous habitats. The fifth species,Ramazzottius varieornatus sp.nov., is new to science, and it can be readily distinguished from the others of the same genus by egg shell morphology, placoids and the type of cuticle.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb02538.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY