Zizka et al. 2015 (Conference Paper) Aechmea, generic concept, systematics

Morphology, collections and molecules? results and perspectives

Author(s):—G. Zizka, E. Leme, J. Paule, S. Heller, B. Kanz, S. Matuszak, K. Weising & A.M. Benko-Iseppon in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—Since 1990, molecular approaches have provided a steadily increasing wealth of information on the systematicsand phylogeny of Bromeliaceae. The monophyly of the family has never been doubted, but the intra-familial classification has recently undergone considerable changes. While the concept of eight subfamilies is widely accepted now, the genus delimitations are in many cases far from being settled. The Aechmea alliance in the subfamily Bromelioideae is one of the most intriguing examples for which phylogenetic analyses identified remarkable polyphyly. At the species level, we face similar problems. In the few cases where comprehensive molecular studies at this level are on hand, we have evidence for gene flow between species and genera. Additionally, thel ow genetic divergence in Bromeliaceae combined with high morphological plasticity and the as yet rudimentary knowledge of key morphological characters suggest that only a holistic approach will lead to a stable taxonomic solution. Another problem whose consequences are not to be overlooked is that species identification in the larger genera lacking recent revision (e.g. Aechmea, Pitcairnia, Puya, Hechtia) is highly problematic, meaning that misidentifications in molecular studies can be comparatively high. More genetic data and comprehensive sampling of groups will surely improve our knowledge and are highly important, e.g. as an essential contribution towards a new generic concept. However, they alone will most probably not be sufficient to establish a broadly accepted genus and species concept in the family. This can only be achieved when the considerable gaps in 'classical' revisions are closed. Some morphological characters are obviously still underexploited (e.g. perianth, stigma, pollen, fruits). Progress in Bromeliaceae systematics could be enhanced considerably if a comprehensive, well documented and reliably determined reference collection could be established with officialised, but feasible access for the international scientific community. Examples are presented, where i) morphological approaches recently helped to identify groups that could be confirmed with molecular methods, ii) different topologies obtained from nuclear and plastid markers tell different stories and indicate special gene flow, and iii) genetic patterns of populations and related species cannot yet be interpreted satisfactorily.

Keywords:—Phylogeny; Morphology; Collections.