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El trabajo llevado a cabo en la presente Tesis representa una puesta al día del registro fósil conocido de lagartos continentales (excepto Iguania) de Argentina, donde la identificación del material fue realizada empleando criterios modernos dentro de un marco cladístico y mediante el contraste directo con abundantes ejemplares actuales del grupo. Durante el desarrollo de la Tesis, se presenta en forma introductoria el marco sistemático y las relaciones filogenéticas de los lagartos, así como una actualización del registro conocido de lagartos fósiles en el mundo, y particularmente, en América del Sur y en Argentina. El objetivo general del trabajo de Tesis doctoral se resume en el estudio sistemático de los fósiles de lagartos continentales presentes en el territorio argentino bajo la consideración de las relaciones filogenéticas planteadas en la Tesis y basadas únicamente en caracteres osteológicos. Debido a que la mayor parte del material fósil estudiado corresponde a la familia Teiidae se describió escuetamente el cráneo del teido actual Tupinambis merianae. Si bien esta especie es ampliamente reconocida y su osteología ya ha sido descripta, aquí se describieron estructuras previamente no observadas. En particular, se describió la dentición de T. merianae, la cual no había sido previamente descripta en detalle teniendo en cuenta todas sus variaciones, que fueron de particular importancia para la interpretación del material fósil. También se reconocieron las diferencias en las características dentarias y estructuras postcraneanas de otros teidos., Facultad de Ciencias Naturales y Museo

In this study, we describe two fossil remains of squamate reptiles found in Middle Pleistocene outcrops at the northern marine cliffs of the city of Mar del Plata (Buenos Aires province). The specimens were found forming a taphocenosis with remains of other microvertebrates (amphibians, mammals and birds). The reptiles recognized in the association are represented by remains of an undetermined colubrid, and the anguid Ophiodes sp. This latter finding represents the first fossil record for the family Anguidae exhumed in Argentina.

The evolution of squamates in South America is the result of the complex geological and paleoclimatic history of this part of the world. The incomplete and episodic fossil record allows us to know only a small part of this evolution. Most Mesozoic squamate remains come from the Patagonian region, but remarkable specimens have also been recovered from Brazil. Both major squamate clades (Iguania and Scleroglossa) are present in the South American Mesozoic. Remains of Mesozoic snakes are common and diverse in Cretaceous deposits, including some of the most primitive terrestrial forms. Paleogene and Neogene squamate remains have been recognized from Argentina, Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela. Paleogene lizard record appears to be scarce in comparison to that of the Mesozoic, whereas snakes show an important Paleogene diversity. At least two extant boid snakes appeared during this epoch (Boa and Corallus). The South American Miocene included some extant genera of Iguania, Teiidae, and Boidae but extinct genera were also present. “Colubrids” appeared at the early Miocene, whereas the first viperid is known from the late Miocene. Most of the Paleogene and early Neogene squamate families and genera have been recognized outside their current range of distribution following favorable climatic conditions for ectothermic vertebrates. During the latest Miocene and Pliocene few extant squamate taxa are found to occur outside their present distribution. The earliest amphisbaenian of South America is known from the Pliocene. Most Pleistocene and Holocene squamate remains are assigned to living genera, and some extant species were recognized. Anat Rec, 297:349–368, 2014. © 2014 Wiley Periodicals, Inc.

The Pliocene squamate reptiles of the Atlantic coast between Mar del Plata and Miramar, Buenos Aires province, Argentina. Teiid and amphisbaenian reptiles from Pliocene beds along the coast of the Buenos Aires province, between Mar del Plata and Miramar, are described. They include previously listed remains as well as unreported material belonging to old collections. They document the presence of the teiid genus Tupinambis in Upper Chapadmalalan and Marplatan (Vorohuan) units. The extinct species “T. onyxodon” Kraglievich 1947 is considered invalid herein; also, previous cites of T. merianae are reevaluated as Tupinambis sp.. Remains of the amphisbaenid Amphisbaena sp. are identified in Upper Chapadmalal beds; they represent so far the earliest record of amphisbaenians in South America.

typicus," but he never described the specimens in any detail or figured them. Due to the fragmentary nature of the material, the affinities of both monotypic genera have been contentious. In a series of papers, Ameghino variously assigned "Diasemosaurus" to the lizard families Agamidae (Ameghino, 1893, 1899) or Iguanidae (Ameghino, 1898), and he considered "Dibolosodon" to be close to either the Proterosauridae (Ameghino, 1893) or Champsosauridae (Ameghino, 1898). Subsequent authors have regarded both genera as lizards. Romer (1956, 1967) tentatively included "Diasemosaurus" within the lizard family Teiidae, although he provided no characters to support those assignments. Estes (1983) regarded "Diasemosaurus" and "Dibolosodon" as nomina dubia, with the former placed within the teiid subfamily Tupinambinae and the latter considered Lacertilia incertae sedis. Estes (1983) apparently was unaware of Ameghino's (1893) original descriptions for both taxa, because he did not cite that paper; instead, he incorrectly listed Ameghino (1898) as the author for both names. Gasparini and Biez (1975) and Biez and Gasparini (1977, 1979) suggested that one of the "Diasemosaurus" specimens (MACN-A 5806-a) showed affinities with the Miocene-Recent tupinambine genus Tupinambis. Donadio (1984) believed that same specimen pertained to a new species of Tupinambis, which he informally named "Tupinambis occidentalis"; a formal description of that species was never published. The only other significant mention of either "Diasemosaurus" or "Dibolosodon" in the literature is Gasparini et al.'s (1986) report that "Diasemosaurus" occurs at a second Patagonian Miocene locality (Gaiman), farther to the north in Chubut Province (Fig. 1). However, Brizuela and Albino (2004) identified only Tupinambis at the Gaiman locality. In this paper we re-describe, figure, and discuss the taxonomic affinities of the three type specimens of "Diasemosaurus occidentalis" and "Dibolosodon typicus."

Los escamosos conforman un exitoso grupo de reptiles que incluye más de 9.600 especies actuales. Su evolución en América del Sur, escasamente ilustrada por un registro fósil incompleto y episódico, es consecuencia de la compleja historia geológica y paleoclimática de esta parte del mundo. El registro del Mesozoico está concentrado principalmente en Argentina y Brasil, con menor presencia en Bolivia. Los principales clados de reptiles escamosos (Iguania y Scleroglossa) aparecen en el registro durante el Cretácico, donde las serpientes eran comunes y diversas, con algunas de las más primitivas formas terrestres. Los escamosos del Paleógeno y Neógeno provienen principalmente de Argentina, Bolivia, Brasil, Colombia, Perú y Venezuela. Los lagartos eran poco comunes en el Paleógeno pero las serpientes muestran una importante diversidad que incluye al menos dos boideos actuales (Boa y Corallus) y formas extintas. El Mioceno es especialmente relevante ya que se reconocen por primera vez algunos géneros actuales de Iguanidae (Liolaemus, Pristidactylus), Teiidae (Tupinambis) y otros Boidae (Eunectes, probablemente Epicrates), aunque también existen géneros extintos. La primera ocurrencia de Colubridae corresponde al Mioceno temprano, mientras que los Scolecophidia aparecen en el registro durante el Mioceno medio y los Viperidae en el Mioceno tardío. El más antiguo Amphisbaenia sudamericano es registrado en el Plioceno y los primeros Gekkonidae, Anguidae y Elapidae son del Pleistoceno. La mayoría de los escamosos del Pleistoceno y Holoceno corresponden a géneros actuales, incluyendo algunas especies vivientes. The squamates are a successful group of reptiles which includes more than 9,600 extant species. Their evolution in South America, scarcely illustrated by the incomplete and episodic fossil record, is a consequence of the complex geological and paleoclimatic history of this part of the world. The Mesozoic squamate record is concentrated in Argentina and Brazil, with less presence in Bolivia. Both major squamate clades (Iguania and Scleroglossa) are present during the Cretaceous, where snakes were common and diverse, involving some of the most primitive terrestrial forms. Paleogene and Neogene squamates were mainly recorded in Argentina, Bolivia, Brazil, Colombia, Peru, and Venezuela. Lizards were uncommon in Paleogene deposits but snakes showed an important diversity which included at least two extant boid snakes (Boa and Corallus) and extinct forms. The Miocene is especially relevant because of the first recognition of some extant genera of Iguanidae (Liolaemus, Pristidactylus), Teiidae (Tupinambis), and other Boidae (Eunectes, probably Epicrates), although extinct genera were also present. First occurrence of Colubridae is from the early Miocene, whereas Scolecophidia appears in the middle Miocene, and Viperidae in the late Miocene. The earliest Amphisbaenia of South America is recorded in the Pliocene, and the earliest Gekkonidae, Anguidae and Elapidae come from the Pleistocene. Most Pleistocene and Holocene squamate remains correspond to living genera, including some extant species. Fil: Albino, Adriana Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Brizuela, Santiago. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The most abundant and diverse records of teiids in the South American Miocene are from early and middle Miocene of Patagonia (Argentina) and Colombia. Only two genera of tupinambines are recognized: Paradracaena and Tupinambis. In this contribution, we describe remains assigned to Tupinambis from the late Miocene Cerro Azul Formation. The fossils were collected in exposures of this unit at several localities in the province of La Pampa, central Argentina. Evolutionary history and biogeography of South American tupinambines were affected by the environmental-climatic change subsequent to the uplift of the Andes. Among the taxa represented in the Miocene, Paradracaena became extinct, whereas Tupinambis survived restricted to environments with a more benign climate, disappearing from Patagonia but not from central Argentina.

The Trelew Member of the Sarmiento Formation (early Miocene) at Gaiman, Chubut province, Argentina, is one of the most prolific South American Cenozoic localities for squamatan remains. Within the lizards, at least three teiids have been cited, but the material has never been described. In this paper, mainly fragmentary dentaries and maxillae from this site are identified as belonging to the genus Tupinambis. These constitute the earliest record of this extant teiid genus. Tupinambis has a wide range of distribution through South America but is presently absent in the Gaiman area. Its occurrence in the early Miocene of Patagonia indicates warmer and more humid climatic conditions than today.