A New Classification of Ficus Subsection Urostigma (Moraceae) Based on Four Nuclear DNA Markers (ITS, ETS, G3pdh, and ncpGS), Morphology and Leaf Anatomy

Abstract

Ficus subsection Urostigma as currently circumscribed contains 27 species, distributed in Africa, Asia, Australia and the Pacific, and is of key importance to understand the origin and evolution of Ficus and the fig-wasp mutualism. The species of subsection Urostigma are very variable in morphological characters and exhibit a wide range of often partly overlapping distributions, which makes identification often difficult. The systematic classification within and between this subsection and others is problematic, e.g., it is still unclear where to classify F. amplissima and F. rumphii. To clarify the circumscription of subsection Urostigma, a phylogenetic reconstruction based on four nuclear DNA markers (ITS, ETS, G3pdh, and ncpGS) combined with morphology and leaf anatomy is conducted. The phylogenetic tree based on the combined datasets shows that F. madagascariensis, a Madagascan species, is sister to the remainder of subsect. Urostigma. Ficus amplissima and F. rumphii, formerly constituting sect. Leucogyne, appear to be imbedded in subsect. Conosycea. The result of the phylogenetic analysis necessitates nomenclatural adjustments. A new classification of Ficus subsection Urostigma is presented along with the morphological and leaf anatomical apomorphies typical for the clades. Two new species are described ─ one in subsect. Urostigma, the other in Conosycea. One variety is raised to species level.

Palaeotropical intercontinental disjunctions revisited using a dated phylogenetic hypothesis with nearly complete species level sampling of Ficus subsect. Urostigma (Moraceae)

“…We used the same evolutionary models for the subsequent analyses (HKY+G except GTR+G for ETS) as used by Chantarasuwan et al . (). An overview of the samples and Genbank accession numbers can also be found there.…”

“…The matrix published by Chantarasuwan et al . () was used for all subsequent analyses. This matrix includes 27 of the 31 currently recognized species in F .…”

“…Urostigma was recently revised by Chantarasuwan et al . () and phylogenetic analyses (Weiblen, ; Jousselin et al ., ; Machado et al ., ; Rønsted et al ., , ; Xu et al ., ; Cruaud et al ., ; Chantarasuwan et al ., ) necessitated an altered delimitation of the subsection. In particular, F. amplissima J.E.Sm.…”

“…subsect. Urostigma in its present circumscription (Chantarasuwan et al ., ) contains a few early diverging species in tropical Africa and Madagascar, which form PIDs with their sister group, consisting of the majority of species, all found in Asia. The Asian species range from India to Japan and throughout the southern part of the Malay Archipelago to Australia and the west Pacific [Fig.…”

“…subsect. Urostigma (Chantarasuwan et al ., ) provides a unique model for testing the alternative PIT hypotheses due to the biogeographical distribution and comprehensive species level sampling (27 out of 31 species and generally several samples per species).…”