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Abstract Detail


Montúfar, Alejandro Torres [1], Ochoterena, Helga [2].

Systematics of the Arachnothryx complex (Guettardeae, Rubiaceae) .

Within the Rubiaceae tribe Rondeletieae several genera were considered to be so closely related that they were suggested to conform the morphological Rondeletia complex. Molecular studies suggested that the Rondeletia complex is polyphyletic, conforming two generic groups, on placed within Rondeletieae while the other is nested within tribe Guettardeae. Consequently, two generic complexes can be considered: the re-defined Rondeletia complex (Rondeletieae) and the Arachnothryx complex (Guettardeae). Despite some clarification on the phylogenetic position of several genera originally considered as part of the Rondeletia complex, there are still conflicts of generic circumscription and uncertain species relationships within both groups. The aims of this study are to resolve the generic relationships within both complexes, to clarify the membership of incerta sedis species and to test the monophylly of genera in both complexes. In this study, we present the largest molecular dataset for the Rondeletia and mainly Arachnothryx complex, by combining three plastid markers (trnK-matK, trnL-F and petD). Our study also integrates evidence from pollen morphology, showing that the endoaperture type and the differences in nexine continuity support the distinction of both generic complexes. Our general results support the current tribal circumscriptions. The results of our combined phylogenetic analysis support the recognition of some genera (Donnellyanthus and Rovaeanthus) currently considered synonyms of Arachnothryx or Rogiera, but at the same time suggest the paraphyly of Arachnothryx to Gonzalagunia. Other genera also deserve taxonomic considerations. Also, the phylogenetic analysis pointed to a controversial circumscription of Arachnothryx buddleioides, which was then carefully studied with morphological evidence that allowed us separating it into morphological groups that resulted in the resurrection of some species and in the recognition of new species.

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1 - Instituto de Biología, Botany, Tercer Circuito s/n, Ciudad Universitaria, Coyoacán, Mexico City, Mx, 04510, Mexico
2 - Universidad Nacional Autonoma de Mexico, Instituto de Biologia, 3er. Circuito Exterior, Ciudad Universitaria, Mexico, DF, 04510, Mexico


Presentation Type: Oral Paper
Session: 41, Systematics III: Euasterids
Location: Sundance 4/Omni Hotel
Date: Wednesday, June 28th, 2017
Time: 1:45 PM
Number: 41002
Abstract ID:302
Candidate for Awards:None

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