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Abstract Detail


Neubig, Kurt [1], Garwood, Nancy [2], Valencia Duarte, Janice [3], Szubryt, Marisa [4], Humphreys, Aelys [5], Jordan, Kristina [6], Whitley, Breanna [7], Russell, Stephen [8].

The origin of Neotropical Trema (Cannabaceae) based on phylogenetic, fossil, and biogeographic data.

Trema (Cannabaceae) is a genus of pioneer trees that can be found in tropical zones throughout Africa, Asia, Australia, and the Americas. However, the origin of that distribution is not well understood. The objective of this study was to determine the origin of Trema in the Neotropics using phylogenetic tools, fossil data and current distributions to integrate evolutionary history, clade ages, and distribution. We used exonic regions of plastomes to reconstruct the phylogeny of multiple representatives of Trema (with representatives across Africa, Asia and the Americas) and all other genera of Cannabaceae. We made an exhaustive search of the fossil literature and chose four conservative fossil ages excluding Trema (Humulus at 23 Ma, Pteroceltis at 38 Ma, Celtis at 56 Ma and Gironniera at 66 Ma) to calibrate an ultrametric analysis of the phylogeny and to understand historical distributions of clades. Phylogenetic reconstruction shows that Parasponia is embedded within Trema and that the Trema + Parasponia clade (Trema s.l.) has a Paleotropical origin. Ultrametric results indicate that the stem lineage of Trema s.l. dates to the early Eocene, consistent with fossil evidence of this lineage. The most recent common ancestor for Trema s.l. dates to early Miocene, while that of the Neotropical Trema clade dates to late Miocene. This is consistent with Miocene fossils of Trema from Peru, but conflicts with Eocene Trema fossils from Oregon. This study highlights the utility and difficulty of integrating phylogenetic, biogeographic and fossil data.

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1 - Southern Illinois University, Dept Of Plant Biology, 1125 Lincoln Dr., Life Science II, Room 420, Carbondale, IL, 62901, United States
2 - Southern Illinois University, Plant Biology, 1125 Lincoln Ave., Life Science II, Mailcode 6509, Carbondale, IL, 62901, United States
3 - Southern Illinois University , Plant Biology Department, 1125 Lincoln Dr., Carbondale, IL, 62901, United States
4 - 1125 Lincoln Drive Room 420, Carbondale, 62901, United States
5 - Department of Ecology, Environment and Plant Sciences, Svante Arrhenius väg 20A, Stockholm, 10691, Sweden
6 - Soutern Illinois University, Plant Biology, 1125 Lincoln Dr, Life Science II, Rm 420, Carbondale, IL, 62901, USA
7 - Southern Illinois University, Department Of Plant Biology, 1125 Lincoln Dr., LSII, Room 420, Carbondale , IL, 62901, United States
8 - Natural History Museum, Core Research Laboratories, SW7 5BD, London, UK


Presentation Type: Oral Paper
Session: SYS2, Systematics II: Rosids part 1 to Asterids part 1
Location: Tucson G/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 8:30 AM
Number: SYS2003
Abstract ID:362
Candidate for Awards:None

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