Amphisbaenians

Autino, A. G. y Montero, R. 2012. Guía de Vertebrados de Bajo La Alumbrera, Catamarca, Argentina. Minera Alumbrera Limited, 224 pp.  Edición rústica: ISBN 978-987-28792-0-4; Edición cartoné: ISBN 978-987-28792-1-1.

Contiene información sobre las 93 especies más conspicuas de los Vertebrados de la región de Bajo De La Alumbrera (Catamarca, Argentina), incluyendo fotografías, dibujos, su descripción, distribución, biología y estado de conservación.

Microvertebrates recovered from archaeological and paleontological sites often provide paleoclimatic and paleoenvironmental information as well as information on the relative chronology of associated stratigraphic sequences. In general, microvertebrate specimens serve as reliable index fossils since they are often closely linked to specific climatic and environmental conditions. The fact that many microvertebrates are frequent prey of a great variety of animals and have very specific habitats, often results in large accumulations of certain groups at very particular places, as is the case of caves and rockshelters. Actualistic as well as taphonomic studies carried out in sites where there are accumulations of small vertebrates allow us to identify the agents involved in the formation and subsequent modification of the faunal assemblages.
In order to illustrate the archaeological applications of the recovery and analysis of microvertebrates, two Argentine case studies are presented in this paper: 1) the iguanid remains at an archaeological site located in the southern Puna of Catamarca province, which were interpreted as the result of a catastrophic death episode during a communal hibernation inside rodent burrows, and 2) the association of amphisbaenid remains inside a ceramic vessel recovered at an archaeological site located in the southern part of Salta province, which were interpreted as the result of intentional human action, with probable ritual-ceremonial purposes (e.g., an offering). This is followed by a comparison of both case studies, illustrating the value of archaeological sediment samples as a source of information for past human activities.

Background. Morphological descriptions comparing Leposternon microcephalum and L. scutigerum have been made previously. However, these taxa lack a formal quantitative morphological characterization, and comparative studies suggest that morphology and burrowing performance are be related. The excavatory movements of L. microcephalum have been described in detail. However, there is a lack of studies comparing locomotor patterns and/or performance among different amphisbaenids sharing the same skull shape. This paper presents the first study of comparative morphometric variations between two closely related amphisbaenid species, L. microcephalum and L. scutigerum, with functional inferences on fossorial locomotion efficiency. Methods. Inter-specific morphometric variations were verified through statistical analyses of body and cranial measures of L. microcephalum and L. scutigerum specimens. Their burrowing activity was assessed through X-ray videofluoroscopy and then compared. The influence of morphological variation on the speed of digging was tested among Leposternon individuals. Results. Leposternon microcephalum and L. scutigerum are morphometrically distinct species. The first is shorter and robust with a wider head while the other is more elongated and slim with a narrower head. They share the same excavatory movements. The animals analyzed reached relatively high speeds, but individuals with narrower skulls dug faster. A negative correlation between the speed and the width of skull was determined, but not with total length or diameter of the body. Discussion. The morphometric differences between L. microcephalum and L. scutigerum are in accord with morphological variations previously described. Since these species performed the same excavation pattern, we may infer that closely related amphisbaenids with the same skull type would exhibit the same excavatory

1 Instituto de Herpetología (Fundación Miguel Lillo) y Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán; Miguel Lillo 251, 4000 – San Miguel de Tucumán, Argentina. E-mails: virginia@unt.edu.ar (VA); ueso@unt.edu.ar (RM); ...

A new species of Amphisbaena is described from a semi-deciduous forest in Conceição do Mato Dentro, southern Espinhaço Range, Minas Gerais, Brazil. The following combined characters can diagnose the new species from all congeners: head round-shaped; two or three precloacal pores sequentially arranged; 190–199 body annuli; 2–3 lateral annuli; 23–25 caudal annuli; autotomy sites on caudal annuli 7–9; 12–14 dorsal segments on midbody annulus; 14–16 ventral segments on midbody annulus; three supralabials; three infralabials; postmalar row present or absent; dorsum light brown, with cream intersegmental sutures; venter cream. To date, the new species is known only from the Espinhaço Range, highlighting the importance of conservation actions for these mountains.