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Abstract Detail



Paleobotanical Section

Stults, Debra [1], Axsmith, Brian [2], Boucher, Lisa [3].

A probable ranunculacean fruit and associated leaves from the Cretaceous Ingersol Shale.

Two impression/compression fossils of fruit with features suggesting affinity with the basal eudicot family Ranunculaceae have been recovered from the Ingersoll Shale Lagerstätte within the Eutaw Formation (Upper Cretaceous – Santonian) in eastern Alabama. This is significant, as the Ranunculaceae was part of the initial eudicot radiation based on its phylogenetic position, but nevertheless has a poor and ambiguous Cretaceous fossil record. One fruit is mature and was preserved while dehiscing numerous (> 6) small, trigonal seeds with a prominent ridge and rugose surface. The second specimen is smaller and had not yet dehisced. The mature fruit shows an elongate pedicle with a flattened receptacle bearing at least four follicles. The immature fruit suggests substantial fusion of the follicles. A rib runs along the outside of each follicle, and extends apically as an elongate process similar to the beaks (large, persistent styles) of several extant ranunculacean fruits like those of Aconitum, Delphinium and Nigella. The apparent fusion of the follicles and particularly long beaks enhance comparison with Nigella. The most common angiosperm leaves at the Ingersoll shale locality are large, intact specimens of the genus Manihotites, which was previously described from other localities in the Eutaw Formation by Edward Berry, but attributed to the Euphorbiaceae. However, the palmate organization, irregular lobing, basal actinodromous venation, and features of the higher order veins are known in the Ranunculaceae and closely related taxa, such as Podophyllum of the Berberidaceae. The cuticles of the new fruit and Manihotites leaves are not well preserved, but the observable features are consistent. Furthermore, the delicate beaks of the fruits and the intact condition of the large Manihotites leaves indicate that they were not transported far. Therefore, we tentatively suggest that these fruits and leaves may be parts of the same plant. Similar leaves with preserved cuticles also occur in the Blackhawk Formation of Utah, indicating that this plant extended at least from the Santonian to the Campanian stages of the Cretaceous, and occurred on both sides of the Western Interior Seaway.

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1 - 27640 Rigsby Road, Daphne, AL, 36526, USA
2 - University of South Alabama, Biology Department, 5871 USA Drive North, Room 124, MOBILE, AL, 36688-0002, USA, 251-689-5136
3 - University of Nebraska, Department of Biology, 6001 Dodge St, OMAHA, NE, 68182-0040, USA

Keywords:
Cretaceous
Ranunculacean fruit
Eutaw Formation
Manihotites
Blackhawk Formation
Ingersol Shale.

Presentation Type: Oral Paper:Papers for Sections
Session: 16
Location: Melrose/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 9:00 AM
Number: 16004
Abstract ID:283
Candidate for Awards:None


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