Abstract Detail

Paleobotany

Serbet, Rudolph [1], Rothwell, Gar W [2].

Developing an organismal concept for the Late Cretaceous cupressaceous conifer Drumhellera Serbet and Stockey.

Drumhellera kurmanniae Serbet et Stockey was originally described as permineralized conifer branching systems with helically arranged pollen cones attached in the axils of needle-like leaves from the extremely diverse Late Cretaceous floras (Campanian-Maastrichtian) that crop out in the badlands around Drumheller, Alberta, Canada. Subsequent collections of additional material from several stratigraphic levels within the Drumheller sequence have provided abundant material to develop a whole plant concept for the species, and to assign it to the subfamily Sequoioideae. Stems are woody with a parenchymatous pith and cortical resin canals. Leaves are linear, helically arranged and have two abaxial rows of stomata. Each leaf has a single resin canal abaxial to the vascular strand. Pollen cones are subtended by a single linear leaf and consist of an axis that bears helically arranged sporophylls, each of which has two to three abaxially attached pollen sacs. Pollen is non-saccate, 12-16 µm in equatorial diameter, with a slightly protruding distal leptoma, circular to elliptical aperture, scabrate sexine, and multi-lamellate nexine. Seed cones are terminal and ellipsoidal, 2 - 3 cm long and 1.7 to 2.3 cm in diameter, with up to 27 helically arranged bract/scale complexes. Bract-scale complexes are peltate to rhomboidal in dorsal view, 1.2 cm long, 1.6 to 1.9 cm wide and 6 mm thick, and up to 70 vascular strands per bract-scale complex. Up to 13 seeds arranged in two rows are attached adaxialy to the peltate bract/scale head. Seeds are inverted, up to 5 mm long and 4 mm wide, with two lateral wings. Drumhellera shows a variety of features that can be found in both extinct and extant taxodioid-grade conifers of the Cupressaceae. Bract-scale complexes are most similar to extinct Metasequoia milleri and Parataxodium wigginsii, and to living Sequoiadendron giganteum. Organismal concepts for extinct taxa document greater species richness of extinct basal Cupressaceae than is found in extant flora, and provide vital data for reconstructing the ecological complexity of western North American Cupressaceae during the Upper Cretaceous and Paleogene.

1 - University Of Kansas, Division Of Paleobotany, Natural History Museum and Biodiversity Institute, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
2 - Oregon State University, Botany and Plant Pathology, 2082 Cordley Hall , Corvallis, OR, 97331, USA

Keywords:
Cupressaceae
Sequoioideae
permineralized
Cretaceous.

Presentation Type: Oral Paper
Session: 28, Mesozoic to Pleistocene Paleobotany
Location: 102/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 2:00 PM
Number: 28003
Abstract ID:836
Candidate for Awards:None