Abstract Detail

Paleobotany

Huegele, Indah [1], Manchester, Steven [2].

The Dakota Sandstone of Kansas was a hotspot for platanaceous diversity during the mid-Cretaceous.

Well known from specimens held at museums worldwide, the Albian-Cenomanian Dakota Formation is valued for its abundant and diverse assemblages of leaves, fruits, and flowers preserved with exquisite detail. Although the Dakota Sandstone flora was described more than 150 years ago, its problematic taxonomy remains unaddressed. Among the leaf types described in early monographs of the flora, we recognize that at least 29 species of 10 genera from the Dakota Sandstone may have platanaceous affinities. These include species that Leo Lesquereux originally placed in Aralia, Aspidiophyllum, Betulites, Cissites, Crataegus, Hymenea, Populites, Sassafras, Sterculia, and Viburnum. Some species, like Aralia wellingtoniana and Viburnum inaequilaterale, resemble subsequently described Cretaceous platanoids such as Eoplatanus or Ettingshausenia. Others, like Aralia masoni and Betulites westii, share features with younger Paleogene taxa such as Macginitiea or Platimeliphyllum. However, many taxa display a suite of characters that do not resemble any particular extinct platanoid genus. Complicating assessment of this unrecognized diversity, some taxa previously attributed to Platanaceae from the Dakota Sandstone (e.g. Protophyllum spp.) have dubious affinities to the family. The diverse array of simple lobed and unlobed, and even compound leaf forms suggests that multiple platanoid taxa lived in close proximity to each other. Rare features like basal lobes in Aspidiophyllum dentatum (similar to that found in Platanus condoni from the Oligocene of Oregon and sometimes in modern species) demonstrate that Platanaceae was morphologically diverse in the Early Cretaceous. Although the Dakota Sandstone shares some taxa (e.g. likely Ettingshausenia) with European floras of similar age, it includes many others that are only found in North America (e.g. Eoplatanus) or are unique to the Dakota Sandstone. Morphometric analyses may help up segregate platanaceous leaf morphotypes and recognize intraspecific variation. These efforts are the first step in clarifying the relationships of these species to other Platanaceae and revising the rich flora of these classic localities.

1 - Florida Museum of Natural History, Dickinson Hall, Museum Rd & Newell Dr., Gainesville, FL, 32611, USA
2 - Florida Museum of Natural History, Dickinson Hall, Museum Rd & Newell Dr. Gainesville, Gainesville, FL, 32611, USA

Keywords:
Paleobotany
Plane Trees
Taxonomy
Cretaceous
Leo Lesquereux
Sycamore Trees
Fossil Leaves
Fossil Identification.

Presentation Type: Poster
Session: P, Paleobotany Posters
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 5:00 PM Time and date to be determined
Number: PPB004
Abstract ID:567
Candidate for Awards:None