Livro de Resumos - Dinossauros do Maranhão

Paleontologia 190
First record of Madtsoiidae (Serpentes) from the Middle Cretaceous
(Albian-Early Cenomanian) of Brazil
1
Programa em Pós-graduação em Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Seção de
Paleontologia, Museu de Ciências Naturais da Fundação Zoobotânica do Rio Grande do Sul, Rua Dr. Salvador
França, 1427, 90690-000, Porto Alegre, RS, Brasil.
2
Bolsista de Doutorado CNPq.
3
Bolsista em aperfeiçoamento FAPEMA.
4
Centro de Pesquisa de Historia Natural e Arqueologia do Maranhão, Rua do Giz, 59 - Praia Grande - 65010-
680, Centro Histórico de São Luís, São Luís, MA, Brasil.
5
Departamento de Biologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal do Maranhão
(UFMA), Avenida dos Portugueses, s/n 0 , Campus Universitário do Bacanga, 65085-580, São Luis, MA, Brasil.
E-mail: alf@ufma.br
Annie Schmaltz Hsiou 1,2 , Ronny A. B. Santos 3,4,5 & Manuel Alfredo Medeiros 4,5
The extinct family Madtsoiidae (Late Cretaceous-Pleistocene) includes fossils mainly known
by vertebral remains, although there are additional records of cranial elements in the
Paleogenous and Neogenous of Australia. There are several works about the systematic
position of Matsoiidae. For many times the group was considered as being a Boidae, a
lineage of very primitive snakes, or a basal alethinophidian monophyletic group. Recently,
new hypothesis was proposed considering Madtsoiidae as archaic, non-alethinophidian
snakes, or even belonging the extant clade Macrostomata. South American (Madtsoiidae?)
fossils are represented in the Late Cretaceous of Argentina (Los Alamitos Formation) by
three genera (Rionegrophis, Alamitophis and Patagoniophis) with four species, all of them
consisting of isolated trunk vertebrae, also reported for the Late Cretaceous of Bolivia
(undetermined fragments). In the Paleogenous, the family is present in the Early
Paleocene of Argentina (Rio Chico Formation) and Early Eocene of Brazil (Itaboraí Basin),
represented by Madtsoia. Here we report the first Middle Cretaceous vertebral remains of
Madtsoiidae, collected in Falésia do Sismito and Laje do Coringa fossiliferous sites, Cajual
Island (early Cenomanian deposits of the Alcântara Formation, Itapecuru Group),
northeastern Brazil. The material is housed at Centro de Pesquisa de História Natural e
Arqueologia do Maranhão (CPHNAMA), in São Luiz, Maranhão State, and consists of two
small isolated trunk vertebrae, probably belonging to the middle (VT-1222) and posterior
(VT-1116) trunk region. The fossils are assigned to Madtsoiidae by the following
combination of characters: middle and posterior trunk vertebrae with moderately or well
developed haemal keel; paracotylar and parazygantral foramina present;
prezygapophyseal processes absent; and diapophyses relatively wide, exceeding the width
across the prezygapophyses at least in posterior trunk vertebrae. This is the oldest
Brazilian snake and the oldest South American record for the family Madtsoiidae.
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