SENI biometric analysis - extinct Scincidae species: Macroscincus coctei (underlined)
Leeway Corucia Research Center (LCRC)
SENI Biometric Analysis on the Extinct Scincidae species: Macroscincus coctei (underlined) It has been determined that through mitochrondrial DNA research that Macroscincus coctei has been linked to the Mabuya genus and may both belong to the same clade. Evidence suggests that due to rafting episodes, Mabuya species occupied the Cape Verde archipelago from West Africa. By the Pleistocene, Macroscincus coctei had occupied the northwestern group of islands and in a case of parallelism, Mabuya villianti occupied the southern group of Cape Verde islands (Carrenza et al.,2001). Both were large Scincids of a somewhat herbivorous nature (based on dentition). The Cape Verde Islands were denuded some five hundred years ago with importation of domestic animals. Working with an extant living relative, Mabuya striata sparsa, many common features were noted. On this work submitted both Macroscincus coctei and Mabuya striata sparsa had a SENI value of .13 ; indicating a similar low canopy arboreal niche. Abstract: Macroscincus coctei, a giant member of the Scincidae, became extinct before a proper study of it's lifestyle could be conducted. The few scientific studies of this species that were done were made after the ecosystem was vastly altered. Using a designed biometric ratio, extant members of the Scincidae were tested. A systematic numerical linkage of a given species to a known ecological niche resulted. The technique was then utilized with Macroscincus coctei to determine it's ecological niche. The SENI is a ratio based on anterior foot length at the junction of the ulna/radius-carpal bones to the longest digit divided by the snout to vent length {SVL} (B. Schnirel, 2003). It had been determined that a relationship seemed to exist between the length of certain body proportions such as the anterior foot length and type of environment common to a given Scincidae species. The more arboreal a skink species, the larger the proportion. The SENI method can be a useful in confirming the environmental niche, and possibly determining the trophic level of extinct skink species unavailable for direct study. Species (Extant) known Ecological Niche Seni Scientific Name/ Common Name Chalcides chalcides Subterranean .01 North African Worm Skink ( Deep-Burrower) Chalcides sepsoides Subterranean .02 North African Ribbon Skink (Shallow-Burrower) Eumeces scheideri Fossorial .06 Berber Skink Tiliqua gigas Fossorial .06 New Guinea Blue-Tongue Skink Hemisphaeriodon gerrardi Semi-Arboreal .11 Pink-Tongue Skink Kabuya striata sparsa Arboreal .13 Kalahari Black Tree Skink (Low-Canopy) Corucia zebrata zebrata Arboreal .17 Common Monkey Skink (High-Canopy) Macroscincus coctei .13 Cape Verde Giant skink Discussion: The SENI biometric ratio has given a good numerical perspective of the differences between Scincidae species in their lifestyle as well as appearance. Since the initial development of the SENI biometric ratio in 2003 and the intial study of the species described in this paper, the Leeway Corucia Research Center has used this method extensively and it has given insight into our research with the extant species: Corucia zebrata. In addition to C/A biometric ratio studies and comparisons of SVL and LOA measurements, the SENI formula is one more tool for comparison of Corucia zebrata with Macroscincus coctei and other members of the Scincidae. References: Adler,G.H. Austin,C.C.; 1995 Dispersal and speciation of skinks amoung archipelagos in the tropical Pacific ocean. Evolutionary Ecology: pp 529-541. Austin, C.C; 1995 Molecular and morphological evolution in south Pacific lizards. Herpetologica: pp.291-300. Carrenza S, Parallel gigantism and complex Arnold EN, colonization patterns in the Cape Mateo JA, Verde scincid lizards: Mabuya and Lopez-Jurado LF, Macroscincus (Reptilia Scincidae) 2001 reveled by mitochrondrial DNA sequences. Proc Bilo.Sci Aug 7, 268 (1476), : 1595-1603. Day, David; 1979 Vanished species. Gallery Books,London,Great Britian: pp. 254-255. Grzimek, Berhard; Grzimek's animal life encyclopedia. 1975 Volume 6 Reptiles, Van Nostrand- Reinhold Company, New York, New York U.S.A.: pp.178-179. Hartdegen, Ruston W. The green tree skink. Reptiles 2003 Magazine, Volume 11-Number 9, September, 2003, Boulder, Colorado, U.S.A.: pp. 42-50. Honda, m. et al. Evolution of Asian and African 1999 Lygosomine skinks of the Mabuya group (reptilia: Scincidae) a molecular perspective. Zoological Science, Volume 16, No. 6 pp. 857-1002, December,1999 Pether, Jim; 2003 In search of Macroscincus coctei. Reptiles Magazine, Volume 11- Number 4, April, 2003, Boulder, Colorado, U.S.A.: pp.70-81. Walls, Jerry G.; Skinks: identification, care, and 1994 breeding. T.F.H. Publications, Neptune City, New Jersey U.S.A.: pp.52-58. Sincerely, Brian LCRC |
All times are GMT -4. The time now is 05:09 PM. |
Powered by vBulletin® Version
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.