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Abstract Detail

Systematics Section

McDade, Lucinda [1], Kiel, Carrie [2], Daniel, Thomas F. [3].

The Tetramerium Lineage (Acanthaceae: Justicieae) revisited: A story of taxonomic polyphyly and parallel evolution of floral morphology.

In our first paper on phylogenetic relationships among members of the Tetramerium lineage (Acanthaceae: Justicieae; Daniel et al. 2008, Syst Bot 33: 416-436), we reported a number of results that were not congruent with existing taxonomic treatments of these plants. This was especially true of New World plants among which only a single non-monospecific genus was shown to be monophyletic with strong support (i.e., Tetramerium). Notably, Anisacanthus, Carlowrightia, Mirandea and Yeatesia were shown to be polyphyletic. Study of the plants in the context of these results in many cases revealed subtle morphological characters to corroborate the phylogeny (e.g., a pollen ultrastructural character supports monophyly of the Mirandea clade which comprises species placed in four genera). We have since sought to advance our knowledge of this interesting lineage by adding taxa to (a) test placement of additional genera putatively associated with this lineage (i.e., Ancistranthus, Kudoacanthus: both are members of the Tetramerium lineage), (b) test monophyly of genera that were sparsely sampled in the original paper (i.e., Megalochlamys, Pachystachys, Populina, Schaueria: monophyly supported for all but the last; cannot be rejected for Schaueria), (c) test the generic placement of two species with odd geographic ranges (i.e., Argentinian Carlowrightia sulcata and West African Schaueria populifolia: neither is placed with other members of their genera), and (d) test our ideas about characters that are congruent with placement of species of both Anisacanthus and Carlowrightia in three clades each. Finally, we present data from seed coat morphology which provides additional corroborating putative synapomorphies for a number of clades.

Broader Impacts:

1 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
2 - Rancho Santa Ana Botanic Garden, 1500 N. College Ave., Claremont, CA, 91711, USA
3 - California Academy of Sciences, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA

Keywords:
Acanthaceae
Tetramerium Lineage
polyphyly
phylogeny
floral morphology
parallel evolution.

Presentation Type: Oral Paper:Papers for Sections
Session: 50
Location: 555A/Convention Center
Date: Wednesday, August 4th, 2010
Time: 8:15 AM
Number: 50002
Abstract ID:243