TY - JOUR
T1 - Morphological, functional and evolutionary aspects of tail autotomy and regeneration in the 'living fossil' Sphenodon (Reptilia: Rhynchocephalia)
AU - Seligmann, Hervé
AU - Moravec, Jiří
AU - Werner, Yehudah L.
PY - 2008/4
Y1 - 2008/4
N2 - Tail autotomy and regeneration are less known in Sphenodon ('Reptilia': Rhynchocephalia) than in Squamata. We examined museum specimens, Sphenodon guntheri (N = 8) and Sphenodon punctatus (N = 172), wild Sphenodon punctatus (N = 19) and Sphenodon sp. skeletons (N = 8). In S. punctatus, unlike in typical Squamata, sexes had similar relative (intact) tail lengths, and regeneration frequencies; tail and body growth was isometric. Tail breakage was usually intravertebral, usually followed by ablation of a variably sized terminal vertebral piece, partly deviating from lizards. Hypothetically, imperfect autotomy results from sphenodon's primitiveness. As in squamates, tail-losers were morphologically more left-side dominant than tail-retainers. Individual directional asymmetries in digit morphology and in digit injury were correlated (in lizards observed only at population level); tail-losers had more fluctuating asymmetry but their exclusion did not facilitate morphological taxonomic distinctions (no 'Seligmann effect'). In S. punctatus, extents and directions of sexual dimorphism paralleled differences between tail-retainers and tail-losers, females resembling tail-losers, also accounting for character interdependence (developmental constraints; employing a method similar to phylogenetic contrasts). The variation in the location of tail injury was correlated with the continuum of variation between injured and intact (pholidotic) morphotypes. These last two phenomena remain to be explored in Squamates.
AB - Tail autotomy and regeneration are less known in Sphenodon ('Reptilia': Rhynchocephalia) than in Squamata. We examined museum specimens, Sphenodon guntheri (N = 8) and Sphenodon punctatus (N = 172), wild Sphenodon punctatus (N = 19) and Sphenodon sp. skeletons (N = 8). In S. punctatus, unlike in typical Squamata, sexes had similar relative (intact) tail lengths, and regeneration frequencies; tail and body growth was isometric. Tail breakage was usually intravertebral, usually followed by ablation of a variably sized terminal vertebral piece, partly deviating from lizards. Hypothetically, imperfect autotomy results from sphenodon's primitiveness. As in squamates, tail-losers were morphologically more left-side dominant than tail-retainers. Individual directional asymmetries in digit morphology and in digit injury were correlated (in lizards observed only at population level); tail-losers had more fluctuating asymmetry but their exclusion did not facilitate morphological taxonomic distinctions (no 'Seligmann effect'). In S. punctatus, extents and directions of sexual dimorphism paralleled differences between tail-retainers and tail-losers, females resembling tail-losers, also accounting for character interdependence (developmental constraints; employing a method similar to phylogenetic contrasts). The variation in the location of tail injury was correlated with the continuum of variation between injured and intact (pholidotic) morphotypes. These last two phenomena remain to be explored in Squamates.
KW - Ablation
KW - Age effects
KW - Brain lateralization
KW - Developmental contrasts
KW - Directional asymmetry
KW - Fluctuating asymmetry
KW - Injury rate
KW - Intraspecific fighting
KW - Sexual differences
KW - Tail length
UR - http://www.scopus.com/inward/record.url?scp=40749159631&partnerID=8YFLogxK
U2 - 10.1111/j.1095-8312.2008.00975.x
DO - 10.1111/j.1095-8312.2008.00975.x
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AN - SCOPUS:40749159631
SN - 0024-4066
VL - 93
SP - 721
EP - 743
JO - Biological Journal of the Linnean Society
JF - Biological Journal of the Linnean Society
IS - 4
ER -