Katia Cristina Machado Pellegrino

A new genus of microteiid lizard from the Atlantic forests of State of Bahia, Brazil, with a new generic name for Colobosaura mentalis, and a discussion of relationships among the Heterodactylini (Squamata, Gymnophthalmidae)

Abstract A new genus and species of microteiid lizard is described from a series of specimens obtained in the leaf litter at Una (15°10′S, 39°03′W) in the Atlantic forest of southern Bahia, Brazil. It is characterized by the presence of prefrontals, frontoparietals, parietals, and interparietal; parietals longer than wide; distinct ear openings and eyelids; two pairs of genials, absence of collar and occipital scales; dorsal scales anteriorly smooth and becoming gradually lanceolate and mucronate posterior to the forelimb; and four regular transverse series of smooth ventrals that are longer than wide, identical in size. A phylogenetic analysis based on external morphology, osteology, and molecular data confirms this new lizard as a member of the Heterodactylini radiation of Gymnophthalminae. The topology recovered by maximum parsimony (MP) analyses reveals that its closest relatives are the sister taxa Colobosaura modesta and Iphisa elegans (BS  =  < 50%; Bremer value  =  2) and the partitioned Bremer indexes indicated that the largest contribution to this relationship comes from morphology; Colobosaura mentalis, for which a new generic name is here proposed, is basal to this radiation. Our analyses confirm a previous hypothesis suggesting Stenolepis as a member of the Heterodactylini radiation and that the clade composed of Colobodactylus and Heterodactylus is the sister group of the clade formed by Colobosaura mentalis-Stenolepis (BS  =  100; Bremer value  =  18), Colobosaura modesta-Iphisa (BS  =  < 50%; Bremer value  =  1), and the new genus here described. The support for Heterodactylini monophyly, on the basis of combined MP analyses is higher (BS  =  96, Bremer value  =  11) than that previously found in molecular-based studies only. Partitioned Bayesian methodology combining molecular and morphological data sets recovered the new genus as the sister taxon (PP  =  0.94) of the clade (PP  =  0.94) formed by I. elegans-C. modesta (PP  =  0.51) and C. mentalis-S. ridleyℝ (PP  =  1.0). An alternative topology demonstrating a paraphyletic Heterodactylini is only weakly supported (PP  =  0.63). Based on the MP topology we discuss tentative scenarios for the evolution of Heterodactylini.

Triploid Karyotype of Leposoma percarinatum (Squamata, Gymnophthalmidae)

Abstract Three “identical” haploid genomes (N = 22; 10M + 12m) comprise the 3n = 66 (30M + 36m) karyotype in the parthenogenetic gymnophthalmid lizard Leposoma percarinatum from Brazil. A hybridization event between a bisexual and a diploid unisexual species might explain the origin of L. percarinatum.

Description and Phylogenetic Relationships of a New Genus and Species of Lizard (Squamata, Gymnophthalmidae) from the Amazonian Rainforest of Northern Brazil

ABSTRACT Marinussaurus curupira, a new genus and species of Gymnophthalmidae lizard is described from Iranduba, state of Amazonas, Brazil. The genus is characterized by an elongate body; short and stout pentadactyl limbs; all digits clawed; single frontonasal; two prefrontals; absence of frontoparietals; interparietal and parietals forming a straight posterior margin, with interparietal shorter than parietals; distinctive ear opening and eyelid; few temporals; three pairs of chin shields; nasal divided; a distinct collar; smooth, mainly hexagonal, dorsal scales; smooth quadrangular ventral scales; two precloacal and three femoral pores on each side in males; pores between three or four scales. Parsimony (PAR) and partitioned Bayesian (BA) phylogenetic analyses with morphological and molecular data recovered the new genus as a member of the Ecpleopodini radiation of the Cercosaurinae. A close relationship of the new genus with Arthrosaura is postulated.

Chromosomal banding patterns in the eyelid-less microteiid lizard radiation: The X1X1X2X2:X1X2Y sex chromosome system in Calyptommatus and the karyotypes of Psilophthalmus and Tretioscincus (Squamata, Gymnophthalmidae)

Cytogenetic studies were performed on five closely related microteiid lizards (Gymnophthalmini), three Calyptommatus species and Psilophthalmus paeminosus from the sand dunes of the middle Sao Francisco river in the semiarid caatinga of the Brazilian state of Bahia and Tretioscincus oriximinensis from the Brazilian Amazon region. The diploid chromosome number in Calyptommatus species was 2n = 58 in females and 2n = 57 in males due to a multiple X1X1X2X2:X1X2Y sex chromosomes system, while P. paeminosus was 2n = 44 (20M+24m): where M = macrochromosomes and m = microchromosomes) and T. oriximinensis 2n = 42 (18M+24m). A single pair of silver staining nucleolar organizing regions (Ag-NORs) characterizes all five species. Incorporation of 5-BrdU (Bromodeoxyuridine) followed by replication R-banding (RBG) karyotyping allowed the identification of the larger pairs of chromosomes through longitudinal bands and the late replicating regions. Our data reinforce the remarkable chromosomal variability that has been found in the Gymnophthalmidae and the importance of using differential staining for comparative cytogenetics within this group of lizards. Chromosomal evolution in Gymnophthalmini seems to have included chromosomal fission and fusion, pericentric inversions and variation in the amount and localization of constitutive heterochromatin and the Ag-NOR pattern. Different mechanisms of sex determination also evolved independently in this radiation.

Karyotypes of a Cryptic Diploid Form of the Unisexual Leposoma percarinatum (Squamata, Gymnophthalmidae) and the Bisexual Leposoma ferreirai from the Lower Rio Negro, Amazonian Brazil

Abstract Karyotypes of Leposoma show a clear differentiation between species of the scincoides group from Brazilian Atlantic Forest (2n  =  52, without distinctive size groups of chromosomes) and those of the parietale group from the Amazon (2n  =  44, with 20M + 24m). In a previous study, we found that in the parietale group the parthenoform Leposoma percarinatum from the state of Mato Grosso, Brazil, exhibited a triploid karyotype (3n  =  66) with 30 macrochromosomes and 36 microchromosomes. It was suggested that this karyotype arose after hybridization between a bisexual species with N  =  22 (10M + 12m) and a hypothetical unisexual cryptic diploid form of the L. percarinatum complex. Herein, we describe the karyotypes for two species of the parietale group occurring sympatrically in the Arquipélago das Anavilhanas, lower Rio Negro, in Amazonian Brazil. The first represents a distinctive diploid parthenogenetic clone of the L. percarinatum complex, and the other is the recently described Leposoma ferreirai. Both species have 44 biarmed chromosomes clearly represented by 20 macrochromosomes and 24 microchromosomes and present Ag-NORs in one pair of the smallest sized microchromosomes; heteromorphism of size for these regions was detected in L. percarinatum. C-banding revealed blocks of constitutive heterochromatin on the telomeric and pericentromeric regions of macrochromosomes and some microchromosomes. The description of a diploid karyotype (2n  =  44, 20M + 24m) for the L. percarinatum complex and its sympatric congener L. ferreirai provides new insight for a better understanding of the origin of parthenogenesis in the L. percarinatum complex.

On the Discovery of Bisexual Populations of the Parthenogenetic Lizard Leposoma percarinatum (Gymnophthalmidae), with Insights into the Origin of Parthenogenesis in Leposoma

Abstract. Leposoma percarinatum is one of the two recognized parthenogenetic species in the lizard family Gymnophthalmidae, and only females have been reported to date. Here we report and describe the first known males attributed to the species from two localities of northwestern Amazonia. We compare the morphological variation (15 meristic and 10 discrete characters, all relevant to species identification in Leposoma) of males and females from these populations with that of specimens from unisexual populations to test the hypothesis that they belong to the same species. We did not find significant morphological differences between unisexual and bisexual populations, except for those associated with sexual dimorphism. Additionally, we reviewed literature dealing with the origin of parthenogenesis in L. percarinatum and we provide some insights into this subject, in view of the discovery of males in this species.