DISTRIBUTION MODELS AND MORPHOMETRIC ANALYSES AS ADDITIONAL TOOLS FOR THE STUDY OF DIVERSIFICATION IN DEYEUXIA VELUTINA, AN ANDEAN GRASS SPECIES

MARÍA A. FERRERO, AGOSTINA B. SASSONE, LILIANA M. GIUSSANI& ANDREA S. VEGA

DARWINIANA

INSTITUTO DE BOTÁNICA DARWINION

Lugar: Buenos Aires; Año: 2020 vol. 8 p. 509 - 524

0011-6793

Rúgolo de Agrasar recognized two varieties of Deyeuxia velutina (D. velutina var. velutina andD. velutina var. nardifolia) based on leaf sheath indumentum, lemma length, and leaf blade direction.However, taxonomic delimitation has been difficult due to occasional overlapping characters. To assessthe infraspecific delimitation of D. velutina, we present a comprehensive study combining morphometricanalyses and a potential distribution model. To explore morphological variation and select diagnosticcharacters, we measured 124 morphological characters in 52 specimens of both varieties and performeda principal coordinate analysis and univariate analyses (Analysis of variance and Kruskal-Wallis nonparametrictest). Both taxa resolved as separate morphological groups. Additionally, a DiscriminantAnalysis was performed to classify the individuals in the predetermined morphological groups. Formodeling the species distribution, 26 specimens of D. velutina var. nardifolia and 68 of D. velutinavar. velutina were georeferenced and 20 environmental variables were analyzed through a MaximumEntropy model. Deyeuxia velutina extends in the high Andean region from Peru to southern Argentina and Chile. Both varieties differed in their geographical limits, a result supported by regression analyses of latitude and longitude on the principal coordinates of the PCoA. Deyeuxia velutina var. nardifolia is restricted to the northern area of distribution while D. velutina var. velutina showed a higher habitat suitability in the southern region. Moreover, D. velutina var. nardifolia is here reported for the first time in San Juan province (Argentina), constituting the austral limit of its geographical distribution. Additional reliable morphological characters were considered in an updated key to the varieties.