International Journal of Morphology
versión On-line ISSN 0717-9502
BARROS-FILHO, José Duarte de; HOHL, Leandro dos Santos Lima y ROCHA-BARBOSA, Oscar. Excavatory Cycle of Leposternon microcephalum Wagler, 1824 (Reptilia, Amphisbaenia). Int. J. Morphol. [online]. 2008, vol.26, n.2, pp. 411-414. ISSN 0717-9502. http://dx.doi.org/10.4067/S0717-95022008000200027.
The excavatory movements of the spade-snouted amphisbaenid Leposternon microcephalum (Reptilia, Squamata) was studied with the aid of videofluorscopy (X-ray) techniques. This allows the observation of skull and column movements along tunneling, and a more detailed motion observation, being so a novel approach for amphisbaenian excavatory rescarches. A single specimen of Leposternon microcephalum was kept in a glass terrarium filled with semoline, and filmed with a scopy (X-ray) machine. Fixed anatomical marks on the head of the specimen were put in drawings from the framed recordings. Selected sequences of the recordings were fragmented in isolated frames for motion observation. The analysis of the recordings revealed a repetitive pattern of excavatory cycles, with retreating and downward bending of the head before its upstroke to compact the substrate tunnel roof. Follows a dropping of the head, which lays over the substrate giving support for the next retreating and downward head bending. This is an essential step that was neglected in earlier cycle descriptions. The initial downward head bending was not previously properly described for spade-snouted amphisbaenians. The excavatory movements of spade-snouted amphisbaenians are usually treated as a two-stepped cycle, but the evidence that this excavatory cycle has three steps is given here.
Palabras clave : Reptilia; Amphisbaenia; Leposternon microcephalum; Scopy; Locomotion.