Abstract Detail

Paleobotany

Herrera, Fabiany [1], Shi, Gongle [2], Knopf, Patrick [3], Leslie, Andrew [4], Ichinnorov, Niiden [5], Takahashi, Masamichi [6], Crane, Peter [7], Herendeen, Patrick [8].

Diversity of taxodiaceous Cupressaceae seed cones from the Early Cretaceous of Mongolia.

Nine taxodiaceous genera compose the most basal clades of the Cupressaceae s.l. Among these living genera, Cunninghamia with two species is sister to the rest of the family. The monotypic genus Taiwania appears one step up in the phylogenetic tree. Both genera are restricted today to eastern Asia where they grow in montane forests. Seed cones of these genera bear helically arranged bract-scale complexes, but their cone scales differ in the absence of a free and conspicuous ovuliferous scale in Taiwania. The early fossil record of Cupressaceae shows a high diversity of Cunninghamia and Cunninghamia-like seed cones, while seed cones with Taiwania features are less common. Two new lignified and well-preserved seed cone taxa are described from the Early Cretaceous (Aptian-Albian) Tevshiin Govi deposit of Mongolia. One of the seed cones is found attached to helically arranged falcate and amphistomatic leaves with two narrow lateral stomatal bands; the seed cones are up to 32 mm long, solitary and terminally borne with 30-70 helically arranged bract-scale complexes, which lack a conspicuous and free ovuliferous scale. Overall, various morphological features suggest a close relationship with Taiwania. However, up to four inverted winged seeds are borne on the bract-scale complexes, contrary to the commonly two-seeded scales seen in living Taiwania. In Addition, anatomical features such as the absence of a branching resin canal system in the bract-scale complex in the new fossil separate the new seed cone from Taiwania. The second new seed cone from Tevshiin Govi is up to 7 mm long with approximately 25-30 helically arranged, papery bract-scale complexes; the margin of the bract-scale complexes is minutely toothed; the adaxial side of the cone scales reveals a denticulate and free ovuliferous scale tip and five diminutive thin winged seeds. The presence of a free ovuliferous scale tip suggests a close relationship with Cunninghamia. A cunninghamioid cupressaceous cone was previously described from a coeval lignite deposit in Mongolia, Elatides zhoui. All these seed cones and leaves from Mongolia provide additional evidence of the remarkable morphological diversity of basal taxodiaceous conifers during the Early Cretaceous. In addition, the extinct Mongolian fossils show that permanently flooded environments were perhaps more ecologically important than in living basal Cupressaceae taxa.

1 - Chicago Botanic Garden, Plant Science Center, 1000 Lake Cook Road, Glencoe, Il, 60022, USA
2 - Nanjing Institute of Geology and Palaeontology, China
3 - Botanischer Garten Rombergpark, Germany
4 - Department of Ecology and Evolutionary Biology, Brown University, USA
5 - Institute of Paleontology and Geology, Mongolian Academy of Sciences, Mongolia
6 - Department of Environmental Sciences, Faculty of Sciences, Niigata Uni, Japan
7 - Yale School of Forestry and Environmental Studies, Yale University, USA
8 - Chicago Botanic Garden, Senior Scientist, 1000 Lake Cook Road, Glencoe, IL, 60022, USA

Keywords:
Cupressaceae
Seed cones
Early Cretaceous
Taiwania
Cunninghamia
Mongolia.

Presentation Type: Oral Paper
Session: 28, Mesozoic to Pleistocene Paleobotany
Location: 102/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 1:30 PM
Number: 28001
Abstract ID:166
Candidate for Awards:None