Abstract Detail

Biogeography

Ashokan, Ajith [1], Gowda, Vinita [2].

Evolution of ginger-lilies: insights into the roles of mountains and monsoons in the botanical diversity of Indo-Malayan Realm.

The Indo-Malayan Realm (IMR) is a biogeographic realm that extends from the Indian subcontinent to the islands of Southeast Asia (Malay Archipelago) through southwest and southcentral China and mainland Southeast Asia. Tectonically, it is spread across three plates (Indian, Eurasian, and Philippine) and is known for hosting many biodiversity hotspots. Despite being megadiverse, evolutionary hypotheses explaining taxonomic diversity in this region have been rare. Here, we investigate the diversification patterns and role of Himalayan orogeny and monsoon intensification in speciation events within the ginger-lilies (Hedychium J.Koenig: Zingiberaceae).
We built the first-ever time-calibrated phylogeny of Hedychium with ~ 75% taxonomic and geographic sampling. We found that Hedychium is a very young lineage that originated only in the Late Miocene (c. 10.6 Ma) of northern Indo-Burma, followed by a late Neogene and early Quaternary diversification, with multiple dispersal events to southern Indo-Burma, Himalayas, Peninsular India, and the Malay Archipelago. We also propose that the intensifications in the Himalayan uplift, as well as the Asian monsoon, might have played pivotal roles in the diversification of Hedychium. Within Hedychium, the occurrence of vegetative dormancy during the dry season was observed in both clades I and II, whereas the strictly epiphytic growth behavior, island dwarfism, lack of dormancy, and a distinct environmental niche was observed only in clade III. Further, clade IV or the most speciose clade in the phylogeny of Hedychium, is known for its highest heterogeneity in both habitat types and elevational ranges, and also consisted of several notorious species complexes in the genus. We conclude that Hedychium serves as an ideal model among perennial rhizomatous herbs that highlights the role of recent geoclimatic changes and environmental factors in the diversification of plants within the Indo-Malayan Realm. Importantly, our study provides valuable insights toward understanding the occurrence of species complexes in Hedychium and also in resolving the taxonomic issues prevalent in this genus.

1 - IISER Bhopal, Biological Sciences, Bhopal, Bhopal, Bhopal, MP, 462066, India
2 - IISER Bhopal, Biological Sciences, Bhopal, Madhya Pradesh, 462066, India

Keywords:
Dormancy
Epiphytism
Historical biogeography
Island dwarfism
Malay Archipelago
Northeast India
Pleistocene
species complex.

Presentation Type: Oral Paper
Number: BIOG III012
Abstract ID:982
Candidate for Awards:None