Crepet, William , Nixon, Kevin , Daghlian, Charles .
New technology old flowers: Extinct taxa from the Cretaceous of New Jersey.
A clade of species from Cretaceous Atlantic Coastal Plain (Turonian) deposits represented by fossil flowers, leaves and inflorescences constitutes a closely related species complex that is unique relative to existing angiosperm genera. Fossils representing this taxon include dispersed individual flowers, inflorescences, fruits, and leaves. Structural details were illuminated using the latest Xradia nano-CTScan technology. These fossils are interpreted as representing a complex of at least three closely related taxa because of common morphological characters of the flowers and fruits. These shared features include: distinctive multicellular glands on the five sepals, five free clawed petals, five stamens alternating with five staminodes, dorsifixed introrse anthers with psilate tricolporate pollen, a superior syncarpellate five-locular ovary with a single style and capitate five-lobed stigma, axile/intruded parietal placentation, numerous seeds, and capsular fruits with loculicidal dehiscence. Flowers vary considerably in other characters including trichome nature and distribution, arrangement of the abaxial sepal glands, length of the stamen filaments, presence or absence of well-defined anther spurs, presence or absence of "viscin" threads attached to in situ pollen, and stigma shape. Because of the presence of viscin threads on pollen, and compatible floral and pollen morphology, Ericaceae/Ericales are the primary targets of combined morphological/molecular cladistic analysis for placement of the fossils, but none of the fossils or reconstructions exactly match any modern genus in all characters. Fossil placement was also tested against several other rosid and asterid families with similar floral morphology. These fossils show the difficulty of placement of Cretaceous fossil flowers in modern families and orders and the caution that must be exercised in doing so. Independent of phylogenetic affinity, the flower fossils have some interesting characteristics suggestive of well-developed relationships with pollinating insects including viscin threads connecting grains in one taxon and possibly nectariferous staminodes. The complex of characters suggest either short-tongued hymenopteran or dipteran pollination syndromes were well-developed at this time.
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1 - Cornell University, L. H. BAILEY HORTORIUM, 408 MANN LIBRARY, ITHACA, NY, 14853-4301, USA
2 - Dartmouth Medical School, Rippel E. M. Facility, Hanover, New Hampshire 03755
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Tuesday, July 10th, 2012
Time: 4:30 PM