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| Gueragama sulamericana Simões, Wilner, Caldwell, Weinschütz & Kellner, 2015 Figure 4: Life reconstruction of Gueragama sulamericana in its palaeohabitat. As the extant agamid Uromastyx in Africa, G. sulamericana also inhabited a desert environment. The new species was found in an ancient oasis along with pterosaurs of the species Caiuajara dobruskii. |
Iguanians are one of the most diverse groups of extant lizards (>1,700 species) with acrodontan iguanians dominating in the Old World, and non-acrodontans in the New World. A new lizard species presented herein is the first acrodontan from South America, indicating acrodontans radiated throughout Gondwana much earlier than previously thought, and that some of the first South American lizards were more closely related to their counterparts in Africa and Asia than to the modern fauna of South America. This suggests both groups of iguanians achieved a worldwide distribution before the final breakup of Pangaea. At some point, non-acrodontans replaced acrodontans and became the only iguanians in the Americas, contrary to what happened on most of the Old World. This discovery also expands the diversity of Cretaceous lizards in South America, which with recent findings, suggests sphenodontians were not the dominant lepidosaurs in that continent as previously hypothesized.
Systematic palaeontology
Squamata Oppel, 1811
Acrodonta Cope, 1864
Gueragama sulamericana gen. et sp.
Etymology.'Guera', meaning 'ancient' (native Brazilian Tupi-Guarani); 'agama' (feminine gender) in reference to agamid lizards; 'sulamericana', meaning 'from South America' (Portuguese).
Holotype. CP.V 2187, partial lower jaw (Fig. 1), CENPALEO—Universidade do Contestado, Santa Catarina, Brazil.
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| Figure 1: Holotype of Gueragama sulamericana. |
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| Figure 4: Life reconstruction of Gueragama sulamericana in its palaeohabitat. As the extant agamid Uromastyx in Africa, G. sulamericana also inhabited a desert environment. The new species was found in an ancient oasis along with pterosaurs of the species Caiuajara dobruskii. Reconstruction: J. Csotonyi. |
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| Figure 3: Phylogenetic position of Gueragama sulamericana among other squamates, and lepidosaur distribution in the Cretaceous of South America. (a) Strict consensus tree of 373 most parsimonious trees of 5,287 steps each (consistency index=0.2012; retention index=0.7714). Branches are proportional to lengths, and emphasized by a colour gradient of increasing branch length as follows: pink, purple, blue, cyan, green, yellow and red. The following clades are denoted: Priscagamidae (pink box), Acrodonta (light orange box), Priscagamidae+Acrodonta+Ctenomastax (grey box). The extremely long branch leading to chamaeleons (Brookesia and Chamaeleo) suggests either the absence of basal fossil forms, or rapid evolutionary rates. (b) Between the Aptian/Albian (112 million years ago (mya) and the Campanian (83 mya), sphenodontians were present in northern Patagonia, in the provinces of Chubut (Tres Cerros), Río Negro (Los Alamitos, Cerro Tortuga, Cerro Bonaparte and La Buitrera) and Neuquén (El Chocón), represented by black circles. Lizards were present in the state of Ceará in northeastern Brazil (Araripe Basin), as well as in the southeastern/southern states of Minas Gerais (Peirópolis), São Paulo (Marília and Presidente Prudente) and Paraná (Cruzeiro do Oeste), and in the province of Río Negro (Cinco Saltos and La Buitrera), Argentina, represented by stars. The red star indicates the type locality of G. sulamericana. DOI: 10.1038/ncomms9149 |
Tiago R. Simões, Everton Wilner, Michael W. Caldwell, Luiz C. Weinschütz and Alexander W. A. Kellner. 2015. The Stem Acrodontan Lizard in the Cretaceous of Brazil Revisions Early Lizard Evolution in Gondwana. NATURE COMMUNICATIONS. 6 (8149): 1-7.