Paleobotany

Cover image showing holotype specimen of Paleoochna with near level of fusion, looking in toward central region of fruit, showing 5 drupelets. Specimen 1, PP 344800.

Cover image showing holotype specimen of Paleoochna tiffneyi near level of fusion, looking in toward central region of fruit, showing 5 drupelets.

Together with Kathleen Pigg at Arizona State University and Melanie DeVore at Georgia College and State University we have documented a number of interesting fossil plants. Focusing on  the Late Paleocene Almont and Beicegel Creek floras from North Dakota provides an unparalleled opportunity to study the changing flora that occurred at this time. Because these unusually preserved floras document both internal anatomy and external surface features of fossil plant remains, they can serve as a benchmark with which to compare two disparate types of data: European seed and fruit assemblages with leaf compression floras of western North America and Asia.  In addition these studies also provide insight into the biogeographic history and development of North American and Asian floras.

We described Paleoochna tiffneyi Ickert-Bond, Pigg, et DeVore gen. et sp. nov. from Almont (Morton County) and Beicegel Creek (McKenzie County), North Dakota (Ickert-Bond, Pigg and DeVore IJPS 2015). On the basis of distinctive anatomical and morphological features, these fruits demonstrate strong taxonomic affinities to Ochna and other members of the family Ochnaceae, but are distinct at the generic level.  The presence of Paleoochna in the late Paleocene Williston Basin and of Rhabdophyllum leaves in the early Eocene Mississippian Embayment suggests an interesting biogeographic connection for the family between the Western Interior Basin and the Gulf Coast during the Paleogene. The species name, tiffneyi, is given in honor of Professor Bruce H. Tiffney, University of California, Santa Barbara, in recognition of his many contributions to Mesozoic and Cenozoic paleobotany, paleobiogeography, and paleobiology.

Fossil with affinity to Actinidiaceae showing 3-loculate fruit with 2 seeds per locule each showing the characteristic papillate epidermis pattern.

3-loculate fossil fruit with 2 seeds per locule each showing the characteristic papillate epidermis pattern seen in extant Actinidiaceae.

Currently, we are working on Almont specimens showing affinities to the kiwifruit family (Actinidiaceae). The pedicellate capsules bear seeds with a distinctive papillate epidermal pattern similar to members of the family Actinidiaceae, including Actinidia (“kiwifruit”) and Saurauria.  Fruits are radially symmetric and three-loculate with around 2 seeds per locule each borne on a prominent funiculus.  The fossil record of Actinidiaceae is of particular interest when placed in a biogeographical context. The family consists of Actinidia (Asia), Clematoclethra (monotypic, China) and Saurauia (Central and South America). The Almont/Beicegel Creek occurrences provide a valuable record useful to understanding the origin of the disjunct distribution of the family.

Previous work at ASU with Kathleen Pigg included the detailed comparison of Middle Miocene Yakima Canyon, Washington State Liquidambar changii fossils with extant sweet gums together with Jun Wen. This collaboration ultimately led to postdoctoral studies at the Field Museum (together with Jun Wen and Jenny McElwain) on extant Altingiaceae.  This work resulted in a number of publications on Altingiaceae (see under projects Altingiaceae).

While at ASU I also worked on Trochodendron and Nordenskioldia (Trochodendraceae) from the middle Eocene (49–50 Ma) Republic flora of northeastern Washington with Kathleen and Wes Wehr (Pigg, Wehr and Ickert-Bond, 2001).