Historical biogeography of Tetrastigma (Vitaceae): Insights into floristic exchange patterns between Asia and Australia

Abstract

Biodiversity exchanges across the Malesian region, linking the distinct biotas of Asia and Australia, have long attracted the curiosity of biologists. Tetrastigma (Vitaceae) has a wide distribution in Asia through the Sunda archipelago to Australia and provides a good case to elucidate floristic exchange between Asia and Australia. Tetrastigma species have fleshy fruits that are consumed by birds, representing a lineage with a predictable dispersal across island chains. We herein estimate the divergence times and reconstruct the biogeographic history of Tetrastigma with intensive taxon sampling (96 of approximately 120 species; >80%) using 10 chloroplast loci. The biogeographic history of Tetrastigma was reconstructed with 4-area and 6-area divisions by delineating the Sunda region into one or three areas of endemism based on a phylogenetic bioregionalization analysis and the geological history of Malesia. The 4-area division shows that Tetrastigma originated in continental Asia and diverged from the recently segregated genus Pseudocayratia in the early Eocene (49.43 Ma). Dispersal from continental Asia might have started in the late Eocene but mainly occurred in the last 10 Myr. Continental Asia is indicated to be the most important source area while Sunda is the biggest sink, with 16 of the 27 dispersal events inferred from continental Asia to Sunda. Only seven dispersal events are inferred arriving in the Sahul plate and one reverse dispersal from Sahul back to Asia. The 6-area division suggests that the Philippines have been an active junction between Asia and Australia. The biogeographic history of Tetrastigma illustrates an asymmetric floristic exchange between Asia and Australia in this genus, which has been facilitated by the formation of terrestrial connections in the late Miocene and the expansion of wet tropical forests across Wallace's Line and beyond.

Asymmetric migration dynamics of the tropical Asian and Australasian floras

“…(2015) indicated that migrations of angiosperm clades from Sunda to Sahul predominated over the reverse direction 2.4 times. Our results are consistent with those reported in previous studies on plant groups that migrated from Asia to Australasia (e.g., Grudinski et al., 2014 ; Crayn et al., 2015 ; Peng et al., 2021 ).…”

“…Most of our sampled lineages (27/29) are components of tropical forests, and there is no evidence of habitat shift during their evolutionary histories. Studies on Tetrastigma have found the establishment of suitable habitats facilitated the southward expansion of species, and their restricted distribution in wet forests of Australia likely reflects the low adaptability of Tetrastigma to new environmental conditions outside their ancestral niche ( Yap et al., 2018 ; Peng et al., 2021 ). In addition, the limited northward dispersal of Tetrastigma might be attributed to competition pressure in the already established northern flora ( Peng et al., 2021 ).…”

“…Studies on Tetrastigma have found the establishment of suitable habitats facilitated the southward expansion of species, and their restricted distribution in wet forests of Australia likely reflects the low adaptability of Tetrastigma to new environmental conditions outside their ancestral niche ( Yap et al., 2018 ; Peng et al., 2021 ). In addition, the limited northward dispersal of Tetrastigma might be attributed to competition pressure in the already established northern flora ( Peng et al., 2021 ). The rates of migrations slowed down since the latest Pliocene were possibly due to contraction of rainforests ( Sniderman et al., 2007 ; Sniderman and Jordan, 2011 ) ( Fig.…”

“…The formation of stepping stones since the middle Miocene has provided possible routes for seed plant migration between tropical Asia and Australasia ( Lomolino et al., 2006 ). The spread of several Vitaceae plants such as Tetrastigma and Cayratia through dispersal by birds was one result of the stepping stones between tropical Asia and Australasia ( Parmar et al., 2021 ; Peng et al., 2021 ). Furthermore, the sea level has declined and fluctuated more frequently ( Fig.…”

Chromosome‐level reference genome of Tetrastigma hemsleyanum (Vitaceae) provides insights into genomic evolution and the biosynthesis of phenylpropanoids and flavonoids

“…Planch. (Vitaceae) comprises about 120 dioecious species of mostly woody lianas, with a wide distribution throughout subtropical and tropical Asia, extending to Australia (Peng et al., 2021; Wen et al., 2018). As the sole perennial herbaceous species of this genus, Tetrastigma hemsleyanum Diels et Gilg (2 n = 2 x = 52) is widespread throughout subtropical China (Wang et al., 2015).…”