Abstract
Symphytum is regarded one of the most complicated genera in terms of the classification of its members among the Boraginaceae. In addition to different infrageneric classification methods, several species complex or aggregates have been proposed to deal with the taxonomical problem of genus members. Symphytum asperum aggregate was first introduced by Kurtto, who proposed six taxa within this aggregate. However, according to further studies by different researchers based on morphological data, total number of species of the complex was variable. The number of species was reduced to three, comprising S. asperum, S. savvalense, and S. sylvaticum, after the phylogenetic and morphological studies of Tarıkahya-Hacıoğlu and Erik. However, the taxonomical status of some of these species (i.e., S. savvalense and S. sylvaticum, and S. sepulcrale), which was assigned as a member of this complex by Kurtto, has been regarded as unresolved. To solve this uncertainty, different species delimitation methods were used, including statistical parsimony network analysis (TCS), generalized mixed Yule coalescent (GMYC), and Bayesian Phylogenetics and Phylogeography (BPP) of the ITS, trnL-F and trnS-G sequence data. In addition to members of this complex, S. ibericum, which is phylogenetically nested within the S. asperum aggregate, was also used. The TCS and GMYC analyses demonstrated more complicated clusters, whereas high posterior probabilities of BPP clusters were more compatible with the morphological data. In accordance with the morphological approach of Tarıkahya-Hacıoğlu and Erik, the species delimitation analyses based on molecular data support the recognition of S. asperum, S. ibericum, S. savvalense, and S. sylvaticum as different species.
References
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Gviniašvili, C.N. (1976) Kavkazskie predstaviteli roda Symphytum L. Boraginaceae Jus, Tbilisi.
Hac?o?lu, B.T. & Erik, S. (2011) Phylogeny of Symphytum L. (Boraginaceae) with special emphasis on Turkish species. African Journal of Biotechnology 10: 15483–15493. https://doi.org/10.5897/AJB11.1094
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Hassanpour, H., Zare-Maivan, H., Sonboli, A., Kazempour-Osaloo, S., Wagner, F., Tomasello, S. & Oberprieler, C. (2018) Phylogenetic species delimitation unravels a new species in the genus Sclerorhachis (Rech.f.) Rech.f. (Compositae, Anthemideae). Plant Systematics and Evolution 304: 185–203. https://doi.org/10.1007/s00606-017-1461-4
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Ho, S.Y.W. (2007) Calibrating molecular estimates of substitution rates and divergence times in birds. Journal of Avian Biology 38: 409–414. https://doi.org/10.1111/j.2007.0908-8857.04168.x
Hu, H., Al-Shehbaz, I.A., Sun, Y., Hao, G., Wang, Q. & Liu, J. (2015) Species delimitation in Orychophragmus (Brassicaceae) based on chloroplast and nuclear DNA barcodes. Taxon 64: 714–726. https://doi.org/10.12705/644.4
Irimia, R.E., Pérez-Escobar, O.A. & Gottschling, M (2015) Strong biogeographic signal in the phylogenetic relationships of Rochefortia Sw.(Ehretiaceae, Boraginales). Plant Systematics and Evolution 301 (5): 1509–1516.
Jackson, N.D., Carstens, B.C., Morales, A.E. & O’Meara, B.C. (2017) Species delimitation with gene flow. Systematic biology 66 (5): 799–812.
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