Evolutive studies in lizards from Teiidae family (Squamata), based on citogenetic and molecular data

Author(s)

Rodrigo Marques Lima dos Santos

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2007-08-06

Examining board members

Yatiyo Yassuda; Pedro Manoel Galetti Junior; Claudio de Oliveira; Miguel Trefaut Urbano Rodrigues; Anita Wajntal

• Advisor: Yatiyo Yassuda

Abstract

The Teiidae family is restrict to neotropical region and comprises around 110 species distributed in ten genera. Molecular studies, besides cytogenetical and morphological data and the new species recently described, reinforces the need of multidisciplinary studies that better comprises the huge diversity found within Teiidae, specially related to Brazilian species, giving lights on the systematics, chromosomal evolution and robust phylogenetic hypotheses. The aim of this work is study cytogenetically and molecularlly lizards form Teiidae family and discuss, if possible, about the parthenogenetical reproduction found in many species from this group of lizards. Karyotypes of five south American species of teiid lizards (Ameiva Ameiva, Cnemidophorus ocellifer, Kentropyx calcarata, K. paulensis and K. vanzoi) are herein described and compared. Meiotic data are also included. Chromosomal data for K. paulensis, K. vanzoi and C. ocellifer are presented for the first time. Differential staining techniques presented revealed many pieces of information about the karyotypic diversity within Teiinae and made possible the comparison between al the species sampled, giving lights on chromosomal evolution and systematics. Karyotypes of Tupinambinae subfamily were described for Crocodilurus amazonicus, Tupinambis merianae, T. quadrilineatus and T. teguixim. The article presented contributes for make clear some cytogenetical incongruences found in literature and describes a specie-specific C-banding pattern for T. quadrilineatus. A molecular phylogenetical propose was obtained for 17 species of teiid lizards, from 1415 bp of mitochondrial (cit B e ND4) and nuclear (c-mos) DNA, using maximum parcimony (MP), maximum likelihood (MV) and bayesian inference (MB) analyses. The consensus tree reconstructed revealed the monofiletism of Teiidae family, as well as for Tupinambinae and Teiinae subfamily plus Cnemidophorini tribe. Whithin Cnemidophorini, the genus Ameiva was monofiletic and basal. Cnemidophorus was parafiletic, with C. leminiscatus closely related to Kentropyx, identified in your turn as monofiletic with K. calcarata basal and K. paulensis sister group of K. vanzoi. The remaining Cnemidophorus species sampled corresponds to the monofiletic group ocellifer, sister group of Kentropyx + C. leminiscatus. Chromosomal evolution of the family was also discussed in face of the molecular phylogenetic hypothesis proposed. Parthenogenesis (virgin birth) is a reproductive mechanism in with an egg develops without fertilization. In this view, for a bisexual species reproduces in that form ,the main obstacle is avoid the reduction of diploid number during meiosis, once that haploid oocites are unlikely to occur in vertebrates. Many cytological studies had attempt to clarify the meiotic events that make possible this reproductive mechanism, without any precise results. This article describes in detail a hypothesys about how delections foun in c-mos sequence may favour the parthenogenetical reproduction, in the form of facultative automitic partenogenesis (PAF), in Lacertiformes and Squamata. (AU)