Newly recognized diversity in Trochodendraceae from the Eocene of Western North America

Steven R. Manchester, Kathleen Pigg, Zlatko Kvaček, Melanie L. Devore, Richard M. Dillhoff

Research output: Contribution to journalArticle

Abstract

The Eocene flora of the Okanogan Highlands in the Pacific Northwest of North America has been recognized previously to include extinct species of both extant genera of the Trochodendraceae. Here, using microcomputed tomography (μCT) scanning to augment traditional methods, we recognize additional diversity, including two new fruit types. Concavistylon wehrii sp. nov. is documented by a fertile twig with attached leaves and an infructescence, allowing for an unusually complete reconstruction of this extinct genus. Concavistyon wehrii infructescences are racemes bearing fruits on short pedicels. Fruits are apically dehiscent capsules with four to six styles. The leaves resemble those of modern Trochodendron in pinnate venation, glandular teeth, and epidermal anatomy but have short petioles. The second new type of infructescence, Pentacentron sternhartae gen. et sp. nov., resembles extant Tetracentron in having small, sessile, apically dehiscent capsules but consistently has five, rather than four, styles. The μCT X-ray imaging demonstrates that fruits of both Concavistylon and Pentacentron differ from those of extant Trochodendraceae in having styles that are concave with stigmas directed inward rather than outward. These fossils, together with previously recognized fossil fruits and leaves of Trochodendron and leaves of Tetracentron from the same beds, indicate that the Trochodendraceae family was more diverse 50–52 Ma than it is today.

Original languageEnglish (US)
Pages (from-to)663-676
Number of pages14
JournalInternational Journal of Plant Sciences
Volume179
Issue number8
DOIs
StatePublished - Oct 1 2018

Fingerprint

Trochodendraceae
Eocene
fruit
Tetracentron
Trochodendron
fruits
leaves
fossils
fossil
micro-computed tomography
new species
pedicel
petioles
stigma
anatomy
tomography
tooth
teeth
highlands
X-radiation

Keywords

  • British Columbia
  • Concavistylon
  • Fruits
  • Infructescences
  • Leaves
  • McAbee
  • Republic
  • Tertiary
  • Tetracentron
  • Trochodendron
  • Washington

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

Cite this

Newly recognized diversity in Trochodendraceae from the Eocene of Western North America. / Manchester, Steven R.; Pigg, Kathleen; Kvaček, Zlatko; Devore, Melanie L.; Dillhoff, Richard M.

In: International Journal of Plant Sciences, Vol. 179, No. 8, 01.10.2018, p. 663-676.

Research output: Contribution to journalArticle

Manchester, Steven R. ; Pigg, Kathleen ; Kvaček, Zlatko ; Devore, Melanie L. ; Dillhoff, Richard M. / Newly recognized diversity in Trochodendraceae from the Eocene of Western North America. In: International Journal of Plant Sciences. 2018 ; Vol. 179, No. 8. pp. 663-676.
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