Change search
ReferencesLink to record
Permanent link

Direct link
Phylogenetic placement, delineation, and relationships among genera of the enigmatic Nelsonioideae (Lamiales: Acanthaceae)
Rancho Santa Ana Botanic Garden.
Department of Botany, California Academy of Sciences.
Department of Botany, Claremont Graduate University.
Stockholm University, Faculty of Science, Department of Botany. (Plant Systematics)
(English)Manuscript (preprint) (Other academic)
Abstract [en]

We took a two-tiered approach to test monophyly of Nelsonioideae and place the group within Lamiales, and to determine relationships among taxa within the group. Phylogenetic analysis of a molecular data set (ndhF + trnLF) for a broad sample of Lamiales supports monophyly of Nelsonioideae and places the clade with strong support as sister to a lineage composed of all other plants treated as Acanthaceae (i.e., Avicennia, Thunbergioideae, Acanthoideae). We propose to treat this entire group as Acanthaceae s.l. and advance indurate, explosively dehiscent capsules as a synapomorphy for the family, albeit with autapomorphic fruit types in Avicennia and Mendoncia. These results further support monophyly of family level groups that have emerged from recent studies of Lamiales but are largely not successful in resolving relationships among these groups, as also encountered by other workers. In fact, our results contradict some aspects of relationships that have seemed resolved by earlier studies, notably among Byblidaceae, Scrophulariaceae, Thomandersia, and other Lamiales. Among Nelsonioideae, analysis of sequence data from more rapidly evolving genic regions (i.e., trnS-G, ndhF-rpl32 + rpl32-trnL(UAG), nrITS) and a larger sample of nelsonioids (i.e., all genera and multiple taxa to represent the diversity of species-rich genera) indicates that Nelsonia and Elytraria are monophyletic with strong support but with only moderate support for Nelsonia as the first branching clade and Elytraria sister to the remaining nelsonioids. An African clade comprising monospecific Saintpauliopsis sister to Anisosepalum (2 of 3 species sampled) is sister to a clade that includes all sampled members of pantropical Staurogyne plus New World Gynocraterium and Asian Ophiorrhiziphyllon. Gynocraterium is sister to all sampled members of New World Staurogyne; this last clade is sister to a clade comprising the other sampled Staurogyne plus Ophiorrhiziphyllon which is nested among Asian Staurogyne. The taxonomic implications of these patterns of relationship are discussed. Our results suggest that Nelsonioideae have a complex history of inter-continental dispersals compared to other acanth lineages of similar to much larger size in terms of number of species, making it an interesting group for biogeographic study.

Keyword [en]
Acanthaceae, Bayesian analysis, Lamiales, Nelsonioideae, parsimony, phylogenetic relationships
National Category
Biological Systematics
Research subject
Systematic Botany; Plant Systematics
URN: urn:nbn:se:su:diva-71075OAI: diva2:483770
Available from: 2012-01-25 Created: 2012-01-25 Last updated: 2012-01-26Bibliographically approved
In thesis
1. Evolutionary relationships in Thunbergioideae and other early branching lineages of Acanthaceae
Open this publication in new window or tab >>Evolutionary relationships in Thunbergioideae and other early branching lineages of Acanthaceae
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Acanthaceae as circumscribed today consists of the three subfamilies Acanthoideae (Acanthaceae sensu stricto), Thunbergioideae and Nelsoniodieae, plus the genus Avicennia. Due to the morphological dissimilarities of Thunbergioideae and Nelsonioideae, the delimitation of the family has been controversial. The mangrove genus Avicennia was only recently associated with Acanthaceae for the first time, based on molecular evidence, but without morphological support. In this thesis, phylogenetic analyses of nuclear and chloroplast DNA sequences were used to test the monophyly and exact positions of Thunbergioideae and Nelsonioideae, and to infer detailed phylogenetic relationships within these subfamilies and among major lineages of Acanthaceae. Floral structure and development were comparatively studied in Avicennia and other Acanthaceae using scanning electron microscopy and stereo microscopy. Phylogenetic analyses strongly support monophyly of Thunbergioideae and Nelsonioideae, and place the latter clade with strong support as sister to all other plants treated as Acanthaceae. Thunbergioideae and Avicennia are moderately supported as sister taxa, and together they are sister to Acanthoideae. The general morphology of Avicennia can be easily accommodated in the Acanthaceae, and three synapomorphies support the suggested sister group relationship of Avicennia and Thunbergioideae: (1) collateral ovule arrangement, (2) vertical orientation of ovule curvature, and (3) an exposed nucellus that is contiguous with the ovary wall. Within Thunbergioideae and Nelsonioideae, support values for major lineages are generally high. With some exceptions, the constituent genera are supported as monophyletic. Evolutionary relationships among and within genera are discussed in a morphological and biogeographical context.

Place, publisher, year, edition, pages
Department of Botany, Stockholm University, 2012. 29 p.
National Category
Research subject
Plant Systematics
urn:nbn:se:su:diva-71080 (URN)978-91-7447-445-9 (ISBN)
Public defence
2012-03-02, föreläsningssalen, Botanicum, Lilla Frescativägen 5, Stockholm, 10:00 (English)
At the time of doctoral defence, the following papers were unpublished and had a status as follows: Papers 2 & 3: ManuscriptsAvailable from: 2012-02-08 Created: 2012-01-25 Last updated: 2012-02-17Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Borg, Agneta Julia
By organisation
Department of Botany
Biological Systematics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 64 hits
ReferencesLink to record
Permanent link

Direct link