Dispariflora robertae gen. et sp. nov., a mid-Cretaceous flower of possible Lauralean affinity from Myanmar amber
DOI:
https://doi.org/10.17348/jbrit.v13.i1.839Abstract
Three flowers of a fossil angiosperm preserved in amber from Myanmar (Burma) are described as the new genus and species Dispariflora robertae. Although joined in a single cymose inflorescence, the flowers are variable in size and, in addition, they possess an unusual perianth in which 1 sepal is much enlarged and leaf-like, while the remaining 4 are smaller and unequal. The flowers each have 1 superior pistil with a peculiarly plumose and bristly ovary. The number of stamens is uncertain because most were lost before floral preservation, but scars on the receptacle suggest that at least 15 were present. The bithecal anthers open by longitudinal slits and basal glands may have been present on the filaments. Taken as a whole, the floral features that characterize Dispariflora suggest an affinity with members of Laurales, especially several Southern Hemisphere families allied with the Monimiaceae.
References
Crane, P.R., E.M. Friis, & K.R. Pedersen. 1994. Paleobotanical evidence on the early radiation of magnoliid angiosperms. Pl. Syst. Evol. (Suppl.) 8:51–72.
Cruickshank, R.D. & K. Ko. 2003. Geology of an amber locality in the Hukawng Valley, northern Myanmar. J. Asian Earth Sci. 21:441–455.
Ellstrand, N.C., E.M. Lord, & K.J. Eckard. 1984. The inflorescence as a metapopulation of flowers: position-dependent differences in function and form in the cleistogamous species Collomia grandiflora Dougl. ex Lindl. (Polemoniaceae). Bot. Gaz. 145:329–333.
Endress, P.K. 1980. Floral structure and relationships of Hortonia (Monimiaceae). Pl. Syst. Evol. 133:199–221.
Fangyuan, X., Y. Gongda, Z. Qingqing, S. Gongle, & W. Bo. 2015. Amber—the elf through time and space. Science Press, Beijing. (In Chinese).
Friis, E.M., P.R. Crane, & K.R. Pedersen. 2011. Early flowers and angiosperm evolution. Cambridge University Press, Cambridge, UK.
Hall, R. 2012. Late Jurassic-Cenozoic reconstructions of the Indonesian region and the Indian Ocean. Tectonophysics 570–571:1–41.
Kubitzki, K. 1993. Hernandiaceae. In: K. Kubitzki, J.G. Rohwer, & V. Bittrich, eds. The families and genera of vascular plants. 2:334–338.
Lord, E.M. 1981. Cleistogamy: a tool for the study of floral morphogenesis, function, and evolution. Bot. Rev. 47:421–449.
Metcalfe, I. 2013. Gondwana dispersion and Asian accretion: tectonic and palaeogeographic evolution of eastern Tethys. J. Asian Earth Sci. 66:1–33.
Moore, S.M. 1923. A new genus of Lauraceae from New Guinea. J. Bot. 61:109.
Pax, F. 1891. Monimiaceae. In: A. Engler & K. Prantl, eds. Die natürlichen Pflanzenfamilien. 3(2):94–105.
Perkins, J. & E. Gilg. 1901. Monimiaceae. In: A. Engler, ed. Das Pflanzenreich. 4(101):1–122.
Philipson, W.R. 1993. Monimiaceae. In: K. Kubitzki, J.G. Rohwer, & V. Bittrich, eds. The families and genera of vascular plants. 2:426–437.
Poinar, G.O., Jr. 2018. Burmese amber: evidence of Gondwanan origin and Cretaceous dispersion. Hist. Biol. 2018:1–6.
Poinar, G.O., Jr. & K.L. Chambers. 2017. Tropidogyne pentaptera sp. nov., a new mid-Cretaceous fossil angiosperm flower in Burmese amber. Palaeodiversity 10:135–140.
Poinar, G.O., Jr. & K.L. Chambers. 2018a. Endobeuthos paleosum gen. et sp. nov., fossil flowers of uncertain affinity from mid-Cretaceous Myanmar amber. J. Bot. Res. Inst. Texas 12:133–139.
Poinar, GO., Jr. & K.L. Chambers. 2018b. Setitheca lativalva gen. et sp. nov., a fossil flower of Laurales from mid-Cretaceous Myanmar amber. J. Bot. Res. Inst. Texas 12:643-653.
Poinar, G.O., Jr., G.J.B. Lambert, & Y. Wu. 2007. Araucarian source of fossiliferous Burmese amber: spectroscopic and anatomical evidence. J. Bot. Res. Inst. Texas 1:449–455.
Renner, S.S. 1999. Circumscription and phylogeny of the Laurales: Evidence from molecular and morphological data. Amer. J. Bot. 86:1301–1315.
Renner, S.S. & G. Hausner. 2005. Siparunaceae. Fl. Neotropica Monogr. 95:1–256.
Rohwer, J.G. 1993. Lauraceae. In: K. Kubitzki, J.G. Rohwer, & V. Bittrich, eds. The families and genera of vascular plants. 2:366–391.
Sampson, F.B. 1975. Aperture orientation in Laurelia pollen (Atherospermataceae, syn. subfamily Atherospermoideae of Monimiaceae). Grana 15:153–157.
Sampson, F.B. 1996. Pollen morphology and ultrastructure of Laurelia, Laureliopsis and Dryadodaphne (Atherospermataceae [Monimiaceae]). Grana 35:257–265.
Sampson, F.B. & D.B. Foreman. 1988. Pollen morphology of Atherosperma, Daphnandra and Doryphora (Atherospermataceae [Monimiaceae]). Grana 27:17–25.
Shi, G., D.A. Grimaldi, G.E. Harlow, J. Wang, M. Yang, W. Lei, Q. Li, & X. Li. 2012. Age constraint on Burmese amber based on U-Pb dating of zircons. Cretaceous Res. 37:155–163.
Stevens, P.F. 2001 onwards. Angiosperm phylogeny website. Version 14, July 2017 (and updated since).
