Endobeuthos paleosum gen. et sp. nov., fossil flowers of uncertain affinity from mid-Cretaceous Myanmar amber
DOI:
https://doi.org/10.17348/jbrit.v12.i1.923Abstract
Endobeuthos paleosum gen. et sp. nov. is based on 6 flowers preserved together in a single block of mid-Cretaceous amber from Myanmar (Burma). The calyx is composed of ca. 50+ small, helically arranged sepals. The corolla consists of 5 imbricate petals forming a sheath-like structure that is usually concealed within the calyx. The petal tips are often spreading and exserted from the calyx. There are numerous stamens, each of which consists of a filament and an enlarged anther connective with a single lateral, bisporangiate theca. Dehiscence is extrorse. The tips of 3 or 4 styles are visible, indicating that the flowers are bisexual. The fossils possess unique features that prevent assignment to any modern family. However, the numerous sepals and stamens and a thickened anther connective may suggest an association of E. paleosum with the family Dilleniaceae.
References
Aymard, G. 1997. Dilleniaceae novae Neotropicae IX. Neodillenia, a new genus from the Amazon basin. Harvard Pap. Bot. 10:121–131.
Aymard, G. 2003. A new species of Doliocarpus and a new species of Tetracera (Dilleniaceae) from Brazil. Novon 13:1–4.
Cruickshank, R.D. & K. Ko. 2003. Geology of an amber locality in the Hukawng Valley, northern Myanmar. J. Asian Earth Sci. 21:441–455.
Dickison, W.C. 1970. Comparative morphological studies in Dilleniaceae. VI. Stamens and young stem. J. Arnold Arbor. 51:403–422.
Dutt, B.S.M. 1978. Anther in Moringa concanensis Nimmo. Curr. Sci. 47:589.
Endress, P.K. & S. Stumpf. 1990. Non-tetrasporangiate stamens in the angiosperms: structure, systematic distribution and evolutionary aspects. Bot. Jahrb. Syst. 122:193–240.
Endress, P.K. & S. Stumpf. 1991. The diversity of stamen structure in the “Lower” Rosidae (Rosales, Fabales, Proteales, Sapindales). Bot. J. Linn. Soc. 107:217–312.
Fraga, C.N. 2008. Three new species of Davilla (Dilleniaceae) from Bahia, Brazil. Brittonia 60: 355–361.
Gilg, E. 1895. Dilleniaceae. In: A. Engler & K. Prantl, eds. Die natürlichen Pflanzenfamilien III. 6. Wilhelm Engelmann Verlag, Leipzig, Germany. Pp. 100–128.
Hall, R. 2012. Late Jurassic-Cenozoic reconstructions of the Indonesian region and the Indian Ocean. Tectonophysics 570–571:1–41.
Horn, J.W. 2007. Dilleniaceae. In: K. Kubitzki, ed. The families and genera of vascular plants. IX. Flowering plants-Eudicots. Springer-Verlag, Berlin, Germany. Pp. 132–154.
Horn, J.W. 2009. Phylogenetics of Dilleniaceae using sequence data from four plastid loci (rbcL, infA, rps4, rpl16 INTRON). Int. J. Pl. Sci. 170:794–813.
Kubitzki, K. 1970. Die Gattung Tetracera (Dilleniaceae). Mitt. Bot. Staatssamml. Münch. 8:1–98.
Metcalfe, I. 2013. Gondwana dispersion and Asian accretion: tectonic and palaeogeographic evolution of eastern Tethys. J. Asian Earth Sci. 66:1–33.
Poinar, G.O. Jr., J.B. Lambert, & Y. Wu. 2007. Araucarian source of fossiliferous Burmese amber: spectroscopic and anatomical evidence. J. Bot. Res. Inst. Texas 1:449–455.
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.
Shi, G., D.A. Grimaldi, G.E. Harlow, Ji Wang, Ju Wang, M. Yang, W. Lei, O. Li, & X. Li. 2012. Age constraint on Burmese amber based on U-Pb dating of zircons. Cretaceous Res. 37:155–163.
