A putative gnetalean gymnosperm Cariria orbiculiconiformis gen. nov et spec. nov from the Early Cretaceous of northern Gondwana


Autoria(s): KUNZMANN, Lutz; MOHR, Barbara A. R.; WILDE, Volker; Bernardes-de-Oliveira, Mary Elizabeth Cerruti
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2011

Resumo

Cariria orbiculiconiformis gen. nov. et spec. nov., a gymnosperm with gnetoid characters is described from the upper Aptian Crato Formation of the Araripe Basin in northeastern Brazil. Gross-morphology and anatomical details have been studied and characters have been discussed in respect to various seed plants. Several of these characters fit best with those of Gnetales and their putative fossil allies. However, the fossil plant cannot be assigned to any known extinct or extant group of seed plants in their current circumscription. Stem gross-morphology, xylotomical characters and epidermal features indicate a gnetophytic relationship, whereas characters of the reproductive organs are rather distinct from those found in extant taxa. The reproductive unit of the new taxon represents a triple organ consisting of two dichasial ovulate structures and one median pollen-producing structure containing smooth, monosulcate, boat-shaped pollen in-situ. Each ovulate structure consists of two distinct pairs of bracts, a sterile one at the base and a fertile one forming a terminal orbicular capsule. Stiff processes found in the apex of the ovulate structure may represent micropylar tubes of seeds, as seen in the Bennettitales-Erdtmanithecales-Gnetales group. C orbiculiconiformis gen. nov. et spec. nov. was ans herbaceous or semi-shrub-like plant that may have been adapted to the r-strategy in a stressful environment. (C) 2011 Elsevier B.V. All rights reserved.

Identificador

REVIEW OF PALAEOBOTANY AND PALYNOLOGY, v.165, n.1/Fev, p.75-95, 2011

0034-6667

http://producao.usp.br/handle/BDPI/30353

10.1016/j.revpalbo.2011.02.005

http://dx.doi.org/10.1016/j.revpalbo.2011.02.005

Idioma(s)

eng

Publicador

ELSEVIER SCIENCE BV

Relação

Review of Palaeobotany and Palynology

Direitos

restrictedAccess

Copyright ELSEVIER SCIENCE BV

Palavras-Chave #fossil gymnosperms #gnetalean affinity #Cariria orbiculiconiformis gen. nov et spec. nov. #late Early Cretaceous #Crato flora #r-strategy #SEED-PLANT PHYLOGENY #EPHEDRA GNETALES #POLLEN ORGAN #MORPHOLOGY #PORTUGAL #BENNETTITALES #EVOLUTION #BRAZIL #CHINA #ULTRASTRUCTURE #Plant Sciences #Paleontology
Tipo

article

original article

publishedVersion