Resumo

GARCIA-HERNANDEZ, Imelda Perla; ESTRADA-RUIZ, Emilio  e  MARTINEZ-CABRERA, Hugo Israel. Fossil woods from the San Carlos Formation (Upper Cretaceous), Chihuahua, Mexico. Bot. sci [online]. 2016, vol.94, n.2, pp.269-280. ISSN 2007-4476.  https://doi.org/10.17129/botsci.438.

In the sediments of the San Carlos Formation (Upper Cretaceous, Coniacian - Maastrichtian) there have been collected a large number of fossil woods that correspond mainly to conifers and in a smaller proportion to angiosperms. From this material, two new records based on vegetative structures are described. The first corresponds to a conifer which has characters present of the Agathoxylon genus, these features are: indistinguishable growth rings, predominantly uniseriate pits, occasionally biseriate, alternate, cross-field pits (oculipore type) of the Cupressoid type, 1-3 per cross-field. The second morphotype is related to Paraphyllanthoxylon anasazi (cf. Lauraceae), which is characterized by vessels solitary and in short radial multiples, simple perforation plates, small, alternate intervascular pits, vessel-ray parenchyma pits with reduced borders, heterocellular multiseriate rays up to four cells wide. These new records strengthen the growing evidence suggesting a close floristic link between the floras of northern Mexico and south-central USA during the Late Cretaceous.

Palavras-chave : conifer; dicotyledonous; North of Mexico; Upper Cretaceous; wood anatomy.

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