... A distinct suite of apomorphic characters separates the Sphenodontida from other lepidosauromorphs and these apomorphies are readily ... displayed by Kallimodon and Sphenodon . Consequently, within the Sphenodontida the position of Clevosaurus is unclear; however, on ...
Tópico(s): Pleistocene-Era Hominins and Archaeology
1988 - Royal Society | Philosophical transactions of the Royal Society of London. Series B, Biological sciences
John Healy, B. G. M. Jamieson,
... punctatus (Gray), a representative of the ‘reptilian’ order Sphenodontida. Secondary spermatocytes contain two greatly elongate (8.0 ... of spermatogenesis and mature sperm suggest that the Sphenodontida are primitive amniotes, with only chelonians having fewer ...
Tópico(s): Sperm and Testicular Function
1994 - Royal Society | Philosophical Transactions of the Royal Society B Biological Sciences
... against a close, sister-group relationship between the Sphenodontida and Squamata.
Tópico(s): Parasite Biology and Host Interactions
1992 - Royal Society | Philosophical Transactions of the Royal Society B Biological Sciences
Tópico(s): Ichthyology and Marine Biology
1985 - | Palaeontographica Abteilung A
Nicholas C. Fraser, Michael J. Benton,
... evolutionary relationships. Cladograms showing possible interrelationships within the Sphenodontida are based on twenty-nine character states.
Tópico(s): Ichthyology and Marine Biology
1989 - Oxford University Press | Zoological Journal of the Linnean Society
B. G. M. Jamieson, John Healy,
Sphenodon has traditionally been regarded as a little changed survivor of the Permo-Triassic thecodont or eosuchian ‘stem reptiles’ but has alternatively been placed in the Lepidosauria as the plesiomorphic or even apomorphic sister-taxon of the squamates. A cladistic analysis of 16 characters from spermatozoal ultrastructure of Sphenodon and other amniotes unequivocally confirms its exceedingly primitive status. The analysis suggests that monotremes are the sister-group of birds; squamates form ...
Tópico(s): Evolution and Paleontology Studies
1992 - Royal Society | Philosophical Transactions of the Royal Society B Biological Sciences
Lorenzo Alibardi, P. F. A. Maderson,
Abstract Study of the histology, histochemistry, and fine structure of caudal epidermal regeneration in Sphenodon punctatus through restoration of a scaled form reveals that the processes involved resemble those known in lizards. Following establishment of a wound epithelium (WE), subjacent scale neogenesis involves epidermal downgrowths into the dermis. Although the process is extremely slow, and most new scales do not overlap, their epidermal coverings reestablish epidermal generation (EG) formation. ...
Tópico(s): Silk-based biomaterials and applications
2003 - Wiley | Journal of Morphology
Lorenzo Alibardi, P. F. A. Maderson,
Abstract Histochemical and TEM analysis of the epidermis of Sphenodon punctatus confirms previous histological studies showing that skin‐shedding in this relic species involves the periodic production and loss of epidermal generations, as has been well documented in the related Squamata. The generations are basically similar to those that have been described in the latter, and their formation involves a cyclic alternation between β‐ and α‐keratogenesis. The six differences from the previously described ...
Tópico(s): Biochemical and Structural Characterization
2003 - Wiley | Journal of Morphology
The formation of the stratum corneum in the epidermis of the reptile Sphenodon punctatus has been studied by histochemical, immunohistochemical, and ultrastructural methods. Sulfhydryl groups are present in the mesos and pre-alpha-layer but disappear in the keratinized beta-layer and in most of the mature alpha-layer. This suggests a complete cross-linking of keratin filaments. Tyrosine increases in keratinized layers, especially in the beta-layer. Arginine is present in living epidermal layers, ...
Tópico(s): Silk-based biomaterials and applications
2004 - Elsevier BV | Zoology
David R. Towns, Charles H. Daugherty, Alison Cree,
... New Zealand comprises the last representatives of the Sphenodontida — two species of tuatara (Sphenodon) — and about 60 ...
Tópico(s): Species Distribution and Climate Change
2001 - Elsevier BV | Biological Conservation
Louis J. Guillette, Alison Cree,
... are rare reptiles, members of the reptilian order Sphenodontida, inhabiting small offshore islands of New Zealand. Females ...
Tópico(s): Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities
1997 - Wiley | Journal of Morphology