Molecular phylogeny of Macaranga, Mallotus, and related genera (Euphorbiaceae s.s.): insights from plastid and nuclear DNA sequence data

Abstract

Macaranga and Mallotus (Euphorbiaceae s.s.) are two closely related, large paleo(sub)tropical genera. To investigate the phylogenetic relationships between and within them and to determine the position of related genera belonging to the subtribe Rottlerinae, we sequenced one plastid (trnL-F) and three nuclear (ITS, ncpGS, phyC) markers for species representative of these genera. The analyses demonstrated the monophyly of Macaranga and the paraphyly of Mallotus and revealed three highly supported main clades. The genera Cordemoya and Deuteromallotus and the Mallotus sections Hancea and Oliganthae form a basal Cordemoya s.l. clade. The two other clades, the Macaranga clade and the Mallotus s.s. clade (the latter with Coccoceras, Neotrewia, Octospermum, and Trewia), are sister groups. In the Macaranga clade, two basal lineages (comprising mostly sect. Pseudorottlera) and a crown group with three geographically homogenous main clades were identified. The phylogeny of the Mallotus s.s. clade is less clear because of internal conflict in all four data sets. Many of the sections and informal infrageneric groups of Macaranga and Mallotus do not appear to be monophyletic. In both the Macaranga and Mallotus s.s. clades, the African and/or Madagascan taxa are nested in Asian clades, suggesting migrations or dispersals from Asia to Africa and Madagascar.

Resurrection of Hancea and lectotypification of Adisca (Euphorbiaceae)

“…Cordemoya can be distinguished by the presence of pollen ornamentation with scabrae and by capitate glandular hairs with multicellular stalks and sessile peltate-stellate hairs with a central cell, while Mallotus is recognized by the presence of a perforate/micro-reticulate pollen ornamentation with scabrae and by spherical to disc-shaped multicellular glandular hairs. The rank of subgenus was assigned to the two strongly supported and geographically distinct Cordemoya clades present in the phylogeny of Kulju et al (2007): subg. Cordemoya from Madagascar and the Mascarenes and subg.…”

How to tackle revisions of large genera: lessons from Macaranga and Mallotus (Euphorbiaceae)

“…The phylogenetic analysis (Kulju et al 2007a) and subsequent transfer of species to Hancea resulted in a well-corroborated infrageneric classification for Hancea, in accordance with the sections already recognised under Mallotus (Fig. 1).…”

“…The first analysis did not comprise enough species (Kulju et al 2007a), but the Macaranga part was well resolved and relatively well supported, but this was hardly the case with Mallotus. Also, the second analysis (Sierra et al submitted), that included many more species and almost for all species morphological data, did not result in a better cladogram for Mallotus, especially the basal branches were badly resolved and certainly not statistically supported.…”

“…A phylogenetic analysis based on four molecular markers (trnL-F, ITS, ncpGS, phyC) showed that Macaranga is a monophyletic group (Kulju et al 2007a), while Mallotus appeared to be paraphyletic. The largest part of Mallotus is a sister group of Macaranga.…”

“…The phylogenetic analyses (Kulju et al 2007a: core phylogeny of the genera based on molecular data; Sierra et al submitted: detailed phylogeny of Mallotus including morphology and anatomy, f. 1) did not provide sufficient data for infrageneric classifications of Macaranga and Mallotus. The first analysis did not comprise enough species (Kulju et al 2007a), but the Macaranga part was well resolved and relatively well supported, but this was hardly the case with Mallotus.…”