Molecular Phylogeny of the Philippine Endemic Genus Antherostele Bremek. (Rubiaceae) Inferred from ITS Data (nrDNA) and Its Conservation Status

Jasper John A. Obico, Grecebio Jonathan D. Alejandro

College of Science and Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines.
Department of Biology, College of Arts and Sciences, University of the Philippines Manila, Manila, Philippines.

DOI: 10.4236/ajps.2012.310169                

Abstract

Antherostele Bremek. is an understudied genus of Rubiaceae endemic to the Philippines formerly comprising four species of shrubs or small trees distributed in Luzon and Visayas. In this first molecular study of the genus, the ITS (nrDNA) was utilized to determine the monophyly of Antherostele, reconstruct its phylogeny, and resolve its placement in Rubiaceae. Furthermore, an update on the assessment of its conservation status of the included species in the genus was done. Antherostele is monophyletic and is nested within the tribe Urophylleae of subfamily Rubioideae which confirms its segregation from Urophyllum and its placement within Urophylleae as proposed by earlier authors based on morphology. However, the relationships of Urophylleae members remain unresolved. Antherostele is united by reflexed corolla, hairs on upper side of the corolla lobes and syngenesious stamens. The montane A. luzoniensis with small leaves is found to be sister to the rest of Antherostele species. Antherostele is hypothesized to originate from montane regions and diversified by forming larger leaves following dispersal to the shaded forest understory. From the five species of Antherostele currently recognized in the study, two are endangered (A. banahaensis, A. grandistipula) and three are critically endangered including a new species (A. callophylla, A. luzoniensis, A. sp. nov.) following the criteria of IUCN.

Keywords

Antherostele; Philippine Endemic; ITS; IUCN; Rubiaceae; Urophylleae

Conflicts of Interest

The authors declare no conflicts of interest.

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