Abstract Detail

Phylogenomics

Niissalo, Matti A. [1], Gardner, Elliot M. [2], Khew, Gillian S. [1], Šída, Otakar [3], Leong-Škorničková, Jana [1].

Whence came these plants most foul? Phylogenomics and biogeography of Orchidantha (Lowiaceae).

Orchidantha (Zingiberales: Lowiaceae) is a small genus of forest herbs, distributed from SE China, Indochina and the Malay Peninsula to Borneo. The genus is best known for their orchid-like flowers that often have foul-smelling, dark labellums, apparently mimicking dead animals or feces, or lighter labellums with a scent resembling mushrooms. Their closest relatives (Strelitziaceae) are found in Africa and South America. Little is known of the relationships of taxa in different parts of the range of the genus, of their character evolution or of the biogeography of the genus. We sampled the genus extensively, including many newly discovered species, and reconstructed the phylogeny of the genus using HybSeq with Orchidantha-specific RNA baits. The phylogenetic reconstructions show that species with dark, foul-smelling flowers form a grade from which a clade of species with paler, mushroom-smelling flowers have emerged. Apart from a single species in the pale-flowered clade, the species from Borneo form a monophyletic clade in the dark-labellum grade.
A biogeographic analysis shows that Orchidantha distribution is best explained by shared ancestral distribution and vicariance, and there is no evidence for long-distance dispersal. The results are consistent with the geological history of SE Asia. Particularly, the relatively early isolation between Indochina and Borneo could be explained by the presence of a sea barrier that developed 10–15 MYA, and the continuous movement between Borneo and Peninsular Malaysia could be explained by a land bridge that existed until c. 5 MYA. The lack of an extensive land bridge may explain the absence of this genus from Sumatra and other Indonesian islands aside from Borneo. The strict reliance on a continuous habitat for the range expansion of Orchidantha can be explained by their fruits and seeds, which lack obvious adaptations for long-distance dispersal. The inability to disperse to new areas may also explain why the extant species have very restricted distribution areas, and highly specific plant-pollinator relationships.

1 - National Parks Board Singapore, Singapore Botanic Gardens, 1 Cluny Road, Singapore, 259569, Singapore
2 - Florida International University, Institute Of Environment, 11200 SW 8th Street, OE 148, Miami, FL, 33199, United States
3 - National Museum, Department of Botany, Cirkusová 1740, Prague, 193 00, Czech Republic

Keywords:
biogeography
genomics
Herbaceous
HybSeq
Lowiaceae
Orchidantha
Zingiberales.

Presentation Type: Oral Paper
Session: PHYLOI, Phyogenomics I
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 11:30 AM(EDT)
Number: PHYLOI007
Abstract ID:260
Candidate for Awards:None