New article published - A Molecular Phylogeny of the Moss Genus Taxithelium (Pylaisiadelphaceae) Based on Plastid, Mitochondrial and Nuclear Markers

Authors: Paulo E.A.S. Câmara, Jonathan Shaw

Abstract

To test infrageneric classification and species delimitation within the pantropical moss genus Taxithelium (Pylaisiadelphaceae), we constructed a molecular phylogeny using three chloroplast loci (trnL, psbT and rps4), three mitochondrial loci (rps3, nad5 and nad4–5) and the nuclear marker ho1. Analyses of each locus separately and in various combinations, all support the monophyly of Taxithelium. Two major clades corresponding to taxonomically recognized subgenera were resolved within the genus. The first clade is composed of at least five smaller groups, four of which only include Southeast Asian plants and one is from the Americas and Africa; the latter is nested within the Southeast Asian groups. The second group appears to have a Southeast Asian origin with two dispersal events into America. Taxithelium is highly variable morphologically and includes plants with pluripapillose leaf cells as well as plants that lack papillae. Our data show that species T. nepalense, T. leptosigmatum, T. concavum, T. instratum, T. lindbergii and T. isocladum are each demonstrably monophyletic. On the other hand, T. planum and T. kerianum as circumscribed today are polyphyletic. The ho1 nuclear locus is used for the first time, with promising results for moss phylogenetic investigation.

Published in Systematic Botany (2013), 38 (4) - Full article: Click here

New article published - Morphology and development of leaf papillae in the Pilotrichaceae

Authors: Ana Gabriela Duarte-Silva, Micheline Carvalho-Silva, Paulo Eduardo Aguiar Saraiva Câmara

Abstract

Sporophyte morphology has been traditionally used in pleurocarpous moss taxonomy. However, in the Pilotrichaceae gametophytic morphology still holds interesting and under-investigated characters. We investigated in greater depth the morphology and development of leaf papillae in the family and assess their usefulness to infer the family’s evolutionary history. Specimens were observed under the scanning electron microscope and seven morphological kinds of papillae were identified, as well as two different pathways of development. Results suggest that papilla morphology and development are phylogenetically informative in the Pilotrichaceae.

Published in Acta Botanica Brasilica, Vol. 27, No 4 (2013) - Full article: Click here