Abstract Detail

Plants at the Cretaceous-Paleogene boundary

Jud , Nathan A [1], Gandolfo, Maria A [2], Wilf, Peter [3], Iglesias, Ari [4].

Remarkable diversity of fossil flowers from the early Paleocene (Danian) Salamanca Formation, Chubut, Argentina.

Gondwanan plant communities from the early Paleocene are poorly known, and this limits our understanding of geographic variation in the recovery of plant communities following the end-Cretaceous extinction event. Recent work on well-preserved angiosperm reproductive structures from the Salamanca Formation in Chubut Province, Argentina is providing important new data on the composition for Patagonian floras. Over the last two years, we have described an extinct member of the Rhamnaceae and two extinct members of Cunoniaceae based on fossil flowers. In parallel, we have described a new species of Menispermaceae based on a fossil fruit and identified a new species of Azolla based on fertile sporophytes. There are at least 11 remaining flower morphotypes of uncertain affinity from two fossil localities, Palacio del los Loros (PL2) and Rancho Grande (RG). Flowers from PL2 have pollen preserved in the anthers or on the perianth parts. All the flowers are less than 1 cm across and most of the undescribed types have reduced petals or lack petals. Nine of the 11 flower morphotypes have characters typical of core-eudicot angiosperms (one or two whorls of 5 perianth parts, sepals with three veins, and tricol(por)ate pollen). Two have characters typical of monocots (perianth parts in 3 and numerous veins supplying the sepals). The description and identification of these flowers contributes to a more complete understanding of the early Paleocene floras of southern South America and permits inferences about biogeographic connection and recovery dynamics in the southern hemisphere following the end-Cretaceous extinction event.

1 - Cornell University, Plant Biology Section School of Integrative Plant Science, 410 Mann Library, Ithaca, NY, 14853, USA
2 - Cornell University, L.H. Bailey Hortorium, Section Of Plant Biology, 410 Mann Library Building, Ithaca, NY, 14853.0, United States
3 - Pennsylvania State University, Geosciences, 537 Deike Bldg., University Park, PA, 16802, United States
4 - Universidad Nacional del Comahue, San Carlos de Bariloche, Rio Negro, Argentina

Keywords:
paleobotany
angiosperms
recovery
Rhamnaceae
Cunoniaceae
Menispermaceae
eudicots
monocots.

Presentation Type: Colloquium Presentations
Session: C01, Plants at the Cretaceous-Paleogene boundary
Location: 101/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 8:30 AM
Number: C01003
Abstract ID:717
Candidate for Awards:None