Tropidogyne euthystyla sp. nov., a new small-flowered addition to the genus from mid-Cretaceous Myanmar amber

Authors: POINAR, GEORGE - Oregon State University; CHAMBERS, KENTON - Oregon State University; Vega, Fernando

Submitted to: Journal of Botanical Research Institute of Texas
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2021
Publication Date: 7/23/2021
Citation: Poinar, G.O., Chambers, K.L., Vega, F.E. 2021. Tropidogyne euthystyla sp. nov., a new small-flowered addition to the genus from mid-Cretaceous Myanmar amber. Journal of Botanical Research Institute of Texas. 15:113–119.

Interpretive Summary: A new flower species is described in mid-Cretaceous Burmese amber. The flower specimen is small (2 mm diameter) and has two stout, erect styles bearing a terminal stigma. The flower fossil adds to the diversity of the genus Tropidogyne and will be of interest to botanists and paleontologists.

Technical Abstract: Tropidogyne euthystyla, described here, is the fourth species of this fossil genus to have been reported from amber deposits in northern Myanmar. The species are alike in features of the calyx, the shape and venation of the inferior ovary, and the absence of petals. They differ in the number and form of the styles, the lobing of the epigynous disc, and whether the flowers are apparently bisexual or unisexual. In the one species for which several flowers are available for study, T. pentaptera, floral diameters vary from 3.5 to 5.0 mm. The present species, known only from a single flower, is the smallest in the genus, with a floral diameter of only 2 mm. It differs from the 3 previously described species in having 2 stout, erect styles bearing a terminal stigma, whereas the other species have 2 or 3 short or long, arching styles that are decurrently stigmatic along the adaxial surface.