Prabha Amarasinghe1,2,3, Sneha Joshi4, Navendu Page5, Lahiru S Wijedasa6,7, Mary Merello8, Hashendra Kathriarachchi9, Robert Douglas Stone10, Walter Judd1,2, Ullasa Kodandaramaiah4, Nico Cellinese2,3. 1. Department of Biology, University of Florida, Gainesville, Florida, 32611, USA. 2. Florida Museum of Natural History, University of Florida, Gainesville, Florida, 32611, USA. 3. Biodiversity Institute, University of Florida, Gainesville, Florida, 32611, USA. 4. Indian Institute of Science Education and Research, Thiruvananthapuram, India. 5. Wildlife Institute of India, Dehradun, India. 6. Integrated Tropical Peat Research Program, NUS Environmental Research Institute (NERI), National University of Singapore, Singapore, 117411. 7. ConservationLinks Pvt. Ltd., 100 Commonwealth Crescent, no. 08-80, Singapore, 140100. 8. Missouri Botanical Garden, St. Louis, MO, USA. 9. Department of Plant Sciences, University of Colombo, Colombo, Sri Lanka. 10. School of Life Sciences, University of KwaZulu-Natal, South Africa.
Abstract
PREMISE: The woody plant group Memecylon (Melastomataceae) is a large clade occupying diverse forest habitats in the Old World tropics and exhibiting high regional endemism. Its phylogenetic relationships have been previously studied using ribosomal DNA with extensive sampling from Africa and Madagascar. However, divergence times, biogeography, and character evolution of Memecylon remain uninvestigated. We present a phylogenomic analysis of Memecylon to provide a broad evolutionary perspective of this clade. METHODS: One hundred supercontigs of 67 Memecylon taxa were harvested from target enrichment. The data were subjected to coalescent and concatenated phylogenetic analyses. A timeline was provided for Memecylon evolution using fossils and secondary calibration. The calibrated Memecylon phylogeny was used to elucidate its biogeography and ancestral character states. RESULTS: Relationships recovered by the phylogenomic analyses are strongly supported in both maximum likelihood and coalescent-based species trees. Memecylon is inferred to have originated in Africa in the Eocene and subsequently dispersed predominantly eastward via long-distance dispersal (LDD), although a reverse dispersal from South Asia westward to the Seychelles was postulated. Morphological data exhibited high levels of homoplasy, but also showed that several vegetative and reproductive characters were phylogenetically informative. CONCLUSIONS: The current distribution of Memecylon appears to be the result of multiple ancestral LDD events. Our results demonstrate the importance of the combined effect of geographic and paleoclimatic factors in shaping the distribution of this group in the Old World tropics. Memecylon includes a number of evolutionarily derived morphological features that contribute to diversity within the clade.
PREMISE: The woody plant group Memecylon (Melastomataceae) is a large clade occupying diverse forest habitats in the Old World tropics and exhibiting high regional endemism. Its phylogenetic relationships have been previously studied using ribosomal DNA with extensive sampling from Africa and Madagascar. However, divergence times, biogeography, and character evolution of Memecylon remain uninvestigated. We present a phylogenomic analysis of Memecylon to provide a broad evolutionary perspective of this clade. METHODS: One hundred supercontigs of 67 Memecylon taxa were harvested from target enrichment. The data were subjected to coalescent and concatenated phylogenetic analyses. A timeline was provided for Memecylon evolution using fossils and secondary calibration. The calibrated Memecylon phylogeny was used to elucidate its biogeography and ancestral character states. RESULTS: Relationships recovered by the phylogenomic analyses are strongly supported in both maximum likelihood and coalescent-based species trees. Memecylon is inferred to have originated in Africa in the Eocene and subsequently dispersed predominantly eastward via long-distance dispersal (LDD), although a reverse dispersal from South Asia westward to the Seychelles was postulated. Morphological data exhibited high levels of homoplasy, but also showed that several vegetative and reproductive characters were phylogenetically informative. CONCLUSIONS: The current distribution of Memecylon appears to be the result of multiple ancestral LDD events. Our results demonstrate the importance of the combined effect of geographic and paleoclimatic factors in shaping the distribution of this group in the Old World tropics. Memecylon includes a number of evolutionarily derived morphological features that contribute to diversity within the clade.