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Abstract Detail

Paleobotanical Section

Rios Santos, Cesar [1], Cevallos Ferriz, Sergio Rafael Silvestre [2].

Anatomical description of three coniferous woods from Jurassic and Cretaceous of Mexico.

Few paleobotanical studies based on conifer fossil woods are known from Mexico. Three woods are described based on their anatomical characters. The first one belongs to the Middle Jurassic Consuelo Formation of Oaxaca; a second one belongs to the Late Jurassic Todos Santos Formation of Chiapas; and the last one belongs to the Late Cretaceous Cabullona Group from Sonora. The anatomical structure of the Middle Jurassic wood has square axial tracheids in cross section with dark content and sporadic tyloses, alternate rounded to poligonals biseriate and triseriate pits with fusiform apertures on radial walls, unicellular axial parenchyma bands with smooth transverse walls and dark contents, rays predominantly biseriated and slightly heterogeneous, 1-2 window-like cross-field pits. Meanwhile the Late Jurassic wood has growth rings, rounded axial tracheids in transverse section, with alternate biseriate and triseriate circular sometimes hexagonal pits on radial walls, some tracheids have organic deposits in the intersection with the rays, tyloses is present, rays are uniseriate to occasionally biseriate and homogeneous, and in the cross-fileds 3-12 araucaroid pits can be found. Finally, the Late Cretaceous wood has growth rings, square axial tracheids in cross section, predominantly uniseriate circular pits with sporadically notches on the edges and oval apertures on radial walls; abundant diffuse axial parenchyma, with dark contents and smooth transverse walls, rays uniseriate and biseriate, homogeneous to slightly heterogeneous, 3 or 4 cupressoid-taxodioid pits per cross-field. The anatomical structure suggests that the Middle Jurassic wood resembles the extint group Cheirolepidiaceae, the Late Jurassic wood is similar to Araucariaceae, and the Late Cretaceous wood resembles Cupressaceae anatomy.

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1 - Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Ciudad Universitaria , Mexico City, D.F., 04510, Mexico
2 - Instituto de Geologia, UNAM, Ciudad Universitaria, Coyoacan, Ciudad de Mexico, D.F., 04510, México

fossil wood
anatomical characters

Presentation Type: Oral Paper:Papers for Sections
Session: 24
Location: Salon 5/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 4:45 PM
Number: 24005
Abstract ID:253
Candidate for Awards:Isabel Cookson Award

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