Geminispermum, an Early Cretaceous (early–middle Albian) cupulate unit from the angiosperm-dominated Puddledock flora of eastern North America
 
More details
Hide details
1
Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
2
Oak Spring Garden Foundation, Oak Spring, Upperville, Virginia 20184, U.S.A.
3
School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511, U.S.A.
4
Department of Geoscience, University of Aarhus, Høegh-Guldbergs Gade 2, DK-8000 Aarhus C, Denmark
Online publication date: 2019-12-16
Publication date: 2019-12-16
 
Acta Palaeobotanica 2019; 59(2): 229–239
 
KEYWORDS
ABSTRACT
A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures.
 
REFERENCES (33)
1.
ANDERSON J.M. & ANDERSON H.M. 2003. Heyday of the Gymnosperms: Systematics and Biodiversity of the Late Triassic Molteno Fructifications. Pretoria: National Botanical Institute.
 
2.
ANDERSON H.M., BARBACKA M.K., BAMFORD M.K., HOLMES W.B.K. and ANDERSON J.M. 2019. Umkomasia (megasporophyll): part 1 of a reassessment of Gondwana Triassic plant genera and a reclassification of some previously attributed. Alcheringa, 43: 43–70.
 
3.
ARCHANGELSKY S. 1963. A new Mesozoic flora from Ticó, Santa Cruz province, Argentina. Bull. Br. Mus. (Nat. Hist.), Geol., 8: 47–92.
 
4.
BARBACKA M. & BÓKA K. 2000. A new Early Liassic fructification of the Caytoniales from Hungary. Acta Palaeobot., 40: 83–109.
 
5.
BOMFLEUR B., DECOMBEIX A.-L., SCHWENDEMANN A.B., ESCAPA I.H., TAYLOR E.L., TAYLOR T.N. & MCLOUGHLIN S. 2014. Habit and ecology of the Petriellales, an unusual group of seed plants from the Triassic of Gondwana. Int. J. Plant Sci., 175: 1062–1075.
 
6.
BRENNER G.J. 1963. The spores and pollen of the Potomac Group of Maryland. Md. Dept. Geology, Mines and Water Res. Bull., 27: 1–215.
 
7.
CAO Z. 1992. Fossil ginkgophytes from Chengzihe Formation in Shuangyashan-Suibin region of eastern Heilongjiang. Acta Palaeontol. Sin., 31: 232–248.
 
8.
CRANE P.R. 1985. Phyogenetic analysis of seed plants and the origin of angiosperms. Ann. Mo Bot. Gard., 72: 716–793.
 
9.
FONTAINE W.M. 1889. The Potomac or younger Mesozoic flora. U.S. Geological Survey Monograph 15: 1–377, plates 371–180.
 
10.
FRIIS E.M., PEDERSEN K.R. & CRANE P.R. 2009. Early Cretaceous mesofossils from Portugal and eastern North America related to the Bennettitales-Erdtmanithecales-Gnetales group. Am. J. Bot., 96: 252–283.
 
11.
FRIIS E.M., CRANE P.R. & PEDERSEN K.R. 2011. Early flowers and angiosperm evolution. Cambridge: Cambridge University Press.
 
12.
FRIIS E.M., PEDERSEN K.R. & CRANE P.R. 2013. New diversity among chlamydospermous seeds from the Early Cretaceous of Portugal and North America. Int. J. Plant. Sci., 174: 530–558.
 
13.
FRIIS E.M., MARONE F., PEDERSEN K.R., CRANE P.R. & STAMPANONI M. 2014. Three-dimensional visualization of fossil flowers, fruits, seeds and other plant remains using synchrotron radiation X-ray tomographic microscopy (SRXTM): New insights into Cretaceous plant diversity. J. Paleontol., 88: 684–701.
 
14.
FRIIS E.M., CRANE P.R. & PEDERSEN K.R. 2019. Chlamydospermous seeds document the diversity and abundance of extinct gnetalean relatives in Early Cretaceous vegetation. Int. J. Plant. Sci., 180: 643–666.
 
15.
GORDENKO N.V. & BROUSHKIN A.V. 2015. Ginkgoales: Some problems of systematics and phylogeny. Paleont. J., 5: 94–100.
 
16.
HOLLICK A. 1930. The Upper Cretaceous floras of Alaska. U.S. Geological Survey Professional Paper, 159: 1–219.
 
17.
KERP H., ABU HAMAD A., VÖRDING B. & BANDEL K. 2006. Typical Triassic Gondwanan floral elements in the Upper Permian of the paleotropics. Geology, 34: 265–268.
 
18.
KIRCHNER M. & MÜLLER A. 1992. Umkomasia franconica n.sp. und Pteruchus septentrionalis n.sp., Fruktifikationen von Thinnfeldia Ettingshausen. Palaeontographica, 224: 63–71.
 
19.
KLAVINS S.D., TAYLOR T.N. & TAYLOR E.L. 2002. Anatomy of Umkomasia (Corystospermales) from the Triassic of Antarctica. Am. J. Bot., 89: 664–676.
 
20.
KRASSILOV V.A. 1979. Cretaceous flora of Sakhalin. Moscow: Nauka.
 
21.
KRASSILOV V.A. & BUGDAEVA E.V. 1988. Protocycadopsid pteridosperms from the Lower Cretaceous of Transbaikalie and the origin of cycads. Palaeontographica, B, 208: 27–32.
 
22.
PATTEMORE G.A. 2016. The structure of umkomasiacean fructifications from the Triassic of Queensland. Acta Palaeobot., 56: 17–40.
 
23.
PEDERSEN K.R., FRIIS E.M. & CRANE P.R. 1993. Pollen organs and seeds with Decussosporites Brenner from Lower Cretaceous Potomac Group sediments of eastern USA. Grana, 32: 273–289.
 
24.
ROBBINS E.I. 1991. Age of Early Cretaceous palynomorphs in the Muirkirk clay pit fossil locality (Prince Georges County, MD). U.S. Geological Survey, Open-File Report, 91–613: 1–7.
 
25.
ROTHWELL G.W. & STOCKEY R.A. 2016. Phylogenetic diversification of Early Cretaceous seed plants: The compound seed cone of Doylea tetrahedrasperma. Am. J. Bot., 103: 1–15.
 
26.
SHI G., LESLIE A.B., HERENDEEN P.S., HERRERA F., ICHINNOROV N., TAKAHASHI M., KNOPF P. & CRANE P.R. 2016. Early Cretaceous Umkomasia from Mongolia: implications for homology of corystosperm cupules. New Phytol., 210: 1418–1429.
 
27.
SHI G., CRANE P.R., HERENDEEN P.S., ICHINNOROV N., TAKAHASHI M. & HERRERA F. 2019. Diversity and homologies of corystosperm seed-bearing structures from the Early Cretaceous of Mongolia. J. Syst. Palaeontol., 17: 997–1029.
 
28.
STAMPANONI M., GROSO A., ISENEGGER A., MIKULJAN G., CHEN Q., BERTRAND A., HENEIN S., BETEMPS R., FROMMHERZ U., BOHLER P., MEISTER D., LANGE M. & ABELA R. 2006. Trends in synchrotron-based tomographic imaging: the SLS experience. In: Bonse U., (eds.) Developments in X-Ray Tomography V, San Diego: Proceedings of SPIE-The International Society for Optical Engineering.
 
29.
STOCKEY R.A. & ROTHWELL G.W. 2009. Distinguishing angiophytes from the earliest angiosperms: A Lower Cretaceous (Valanginian-Hauterivian) fruit-like reproductive structure. Am. J. Bot., 96: 323–335.
 
30.
TAYLOR T.N. & ARCHANGELSKY S. 1985. The Cretaceous pteridosperms Ruflorinia and Ktalenia and implications on cupule and carpel evolution. Am. J. Bot., 72: 1842–1853.
 
31.
TAYLOR T.N., DEL FUEYO G.M. & TAYLOR E.L. 1994. Permineralized seed fern cupules from the Triassic of Antarctica: Implications for cupule and carpel evolution. Am. J. Bot., 81: 666–677.
 
32.
THOMAS H.H. 1925. The Caytoniales, a new group of angiospermous plants from the Jurassic rocks of Yorkshire. Phil. Trans. R. Soc. London B, 213: 299–363.
 
33.
ZAN S.Q., AXSMITH B.J., FRASER N.C., LIU F. & XING D. 2008. New evidence for Laurasian corystosperms: Umkomasia from the Upper Triassic of Northern China. Rev. Palaeobot. Palynol., 149: 202–207.
 
 
CITATIONS (3):
1.
Melloniflora, a New Extinct Multiparted Flower from the Early Cretaceous of Virginia, USA
Else Friis, Peter Crane, Kaj Pedersen
International Journal of Plant Sciences
 
2.
Mesozoic cupules and the origin of the angiosperm second integument
Gongle Shi, Fabiany Herrera, Patrick Herendeen, Elizabeth Clark, Peter Crane
Nature
 
3.
Microsporangiophores from the Early Cretaceous (Berriasian) of Bornholm, Denmark, with comments on a pre-angiosperm xerophytic flora
Else Friis, Peter Crane, Kaj Pedersen
Review of Palaeobotany and Palynology
 
eISSN:2082-0259
ISSN:0001-6594