Abstract Detail

Paleobotanical Section

Doria, Gabriela [1].

The structure, relationships and biology of Elaterosporites pollen from the Mid-Cretaceous of tropical South America.

Elater-bearing palynomorphs from the mid-Cretaceous of tropical paleolatitudes are a defining element of the African-South American Cretaceous biogeographic province. In spite of the widespread record of dispersed elaterate fossil pollen, the botanical affinities of elaterates are unknown. Moreover, the relationships between the very heterogeneous elater-bearing taxa are uncertain and little has been discussed on the potential biological implications of pollen morphology in this group. I re-examine the morphological diversity of fossil elaterates focusing on the detailed characterization at the morphological and ultrastructural level of Elaterosporites protensus (Stover) Jardiné, 1967, from Albian to Cenomanian sediments of northeastern Peru. The basic architectural plan of Elaterosporites is derived from an oblate pollen grain, monoaperturate, with five elaborated ribs parallel to the equatorial axis of the body. This basic architectural plan resembles patterns in some elaterate taxa (e.g. Galeacornea, Alaticolpites, Elateroplicites, Pentapsis, Senegalosporites), but it is quite different from other pollen genera which highlights the diversity of the group. The presence of well developed granular to alveolar infratectum in Elaterosporites protensus supports previous ideas of a relationship with extant Gnetales, however the absence of a thick laminated endexine is a significant difference from the pollen of extant and fossil Gnetales. Other unusual features of E. protensus include the deep heteropolarity of the body, the strongly thickened rim around the distal aperture and the distinctive, elater-like prolongations of the ektexine, all of which suggest specialization in aspects of pollination biology compared to extant and fossil Gnetales. Considerations of pollen function, as well as analogues among extant plants, suggest that these specializations reflect extreme modifications for insect pollination and optimization for pollen delivery and pollen grains competition. Elaterates might represent an extinct plant group with sophisticated pollination mechanisms thriving during the early phases of angiosperm diversification in the tropics.

Broader Impacts:

1 - Yale University, School of Forestry And Environmental Studies, C/o The Doctoral Program, 195 Prospect Street, New Haven, CT, 06511, USA

Keywords:
Albian
Cenomanian
palynology
Neotropics
Peru
Gnetales.

Presentation Type: Oral Paper:Papers for Sections
Session: 3
Location: Melrose/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 11:00 AM
Number: 3011
Abstract ID:915
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award