doi:10.1016/j.revpalbo.2006.07.006
Copyright © 2006 Elsevier B.V. All rights reserved.
A voltzialean pollen cone from the Triassic of Antarctica
References and further reading may be available for this article. To view references and further reading you must
purchase this article.
Elizabeth J. Hermsen
, a, 
, Thomas N. Taylora and Edith L. Taylora
aUniversity of Kansas, Department of Ecology and Evolutionary Biology, and Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Haworth Hall, Lawrence, Kansas 66045, USA
Received 6 February 2006;
revised 1 July 2006;
accepted 16 July 2006.
Available online 20 September 2006.
Abstract
Leastrobus fallae gen. et sp. nov. is a morphotaxon representing structurally preserved microsporangiate strobili with in situ pollen from the Triassic of Antarctica. The small cone consists of a central axis with a region of helically arranged microsporophylls subtended by elongate, bilaterally symmetrical bracts. Each microsporophyll is differentiated into a pedicel and a laminar head; numerous (ca. 7) elongate microsporangia are attached to the inner surface of the laminar head. Pollen is protosaccate with two large sacci, a corpus with reticulate ornamentation, and a well-defined distal aperture. Leastrobus represents the first documented microsporangiate conifer cone and the first evidence of “Voltziales” from the permineralized floras of the Triassic of Antarctica. The combination of polysporangiate microsporophylls, sporangia free of the sporophyll pedicel, and bisaccate, protosaccate pollen suggests that Leastrobus represents a member of the “Voltziales” most similar to the European genus Ruehleostachys.
Keywords: Antarctica; Conifer; Fremouw Formation; Pollen; Triassic; Voltziales
Plate I. Anatomical characteristics of the Leastrobus fallae cone.
- 1 Transverse section of microsporangiate cone showing peltate microsporophylls and pollen sacs; arrows indicate positions of seven microsporangia attached to the inner face of the microsporophyll. Abbreviations: A = central axis of the pollen cone; S = sporophyll. Slide no. 22473 (holotype); scale bar = 0.9 mm.
2 Transverse section of central axis of pollen cone showing thick-walled cell possibly representing a pitted tracheid (arrow). Slide no. 22482 (holotype); scale bar = 0.1 mm.
3 Surface view of bract subtending the region of the sporophylls. Slide no.22493 (paratype); scale bar = 0.45 mm.
4 Longitudinal section of microsporangiate cone showing peltate microsporophylls (arrows). Slide no. 22485 (paratype); scale bar = 0.63 mm.
5 Section of resin canal in possible bract or leaf subtending the region of the sporophylls. Note delicate epithelium. Slide no. 22491 (paratype); scale bar = 0.19 mm.
6 Tracheids in sporophyll pedicel showing circular pitting. Slide no. 22473 (holotype); scale bar = 35 μm.
7 Tracheids in sporophyll pedicel showing helical thickenings. Slide no. 22475 (holotype); scale bar = 10 μm.
Plate II. Palynological characteristics of Leastrobus fallae.
- 1 Pollen grain macerated from cone showing two invaginated sacci. Slide no. 22480 (pollen macerated from holotype); scale bar = 31 μm.
2 Detail of in situ pollen grain showing the distal aperture between sacci (arrow). Slide no. 22474 (holotype); scale bar = 20 μm.
3 Proximal view of surface of corpus (split laterally) of pollen grain showing reticulate ornamentation. Slide no. 22480 (pollen macerated from holotype); scale bar = 20 μm.
4 Detail of protosaccus of pollen grain. Slide no. 22481 (pollen macerated from holotype); Scale bar = 10 μm.
Table 1.
Comparison of basic features of Leastrobus to selected Late Paleozoic to Triassic pollen cones with polysporangiate microsporophylls, bisaccate pollen, and similar overall structure
1Clement-Westerhof (1974) reported cones similar in structure to U. frumentaria from the Permian of Italy; these cones have 6–8 pollen sacs, average 3 cm in length, and have similar pollen.
Corresponding author.
Abstract
Purchase PDF (1530 K)
E-mail Article
Add to my Quick Links
Cited By in Scopus (1)
Purchase PDF (10832 K)
