Abstract Detail

Mesozoic and Cenozoic plant evolution and biotic change: A symposium in honor of Ruth Stockey

Cevallos Ferriz, Sergio Rafael Silvestre [1], Huerta-Vergara, Alma Rosa [2], Hernández Damián, Ana Lilia [3].

Reproductive structures from the Middle Cretaceous of El Chango quarry, Chiapas, Mexico.

The Cretaceous plants form Mexico have been only sporadically studied, though some localities with nicely preserved plant organs are known. The Upper Cretaceous impression/compression material from the “Zona Carbonífera (Carboniferous Zone)” and the permineralized fruits from Rincón Colorado and Presa San Antonio are better known. In recent years material ca 100 my old from the El Chango quarry, in Ocozocoautla de Espinoza, Chiapas, has yield an interesting conifer flora with few angiosperms represented by leaves, fruits and flowers. An epiphyllius, small flower with a biseriate not differentiated perianth, composed of six structures slightly fused in their proximal zone that may be compared with leaf-like structures, develops from the adxial surface of a symmetrical leaf-like organ with acute apex and a prominent mid-vein that is flanked by two weaker basal veins that do not reach the entire margin. From the same strata a fruit with almost spherical form, and a strong pedicel resembles a berry. The similarities of these two organs with the reproductive structures of Ruscaceae, and especially with Ruscus suggest that a member of the group was present at that time. A third reproductive organ seems to be also composed of a leaf like structure, perhaps an involucre, and a nut-like fruit with a single style. The organization of this structure resembles some reproductive units of Betulaceae, especially Corylus, but further comparison is needed to confirm its taxonomic affinity. Further work will clarify the taxonomic affinities of these materials.

1 - Instituto de Geologia, UNAM, Ciudad Universitaria, Coyoacan, Ciudad de Mexico, D.F., 04510, México
2 - Facultad De Ciencias, UNAM, Biología, Calle 2 #34, Col. Del Maestro; Azcapotzalco, México, D.F., N/A, 02040, Mexico
3 - Universidad Nacional Autonoma de Mexico, Posgrado en Ciencias Biologicas, Av. Ciudad Universitaria 3000, Coyoacan, Mexico City, 04510, Mexico

Keywords:
Cretaceous
angiosperms
flowers
Fruit
El Chango, Chiapas.

Presentation Type: Symposium Presentation
Session: SY14
Location: Salon 5/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 10:15 AM
Number: SY14006
Abstract ID:271
Candidate for Awards:None