<i>Ranunculus dahlgreniae</i> (section <i>Batrachium</i>, Ranunculaceae), a new species from Crete, Greece, with remarks on taxonomy and phylogenetic relations within the section

Abstract

A new species, <i>Ranunculus dahlgreniae</i>, is described from a seasonal lake at Omalos Plateau, Lefka Ori Mountains, western Crete, Greece. The heterophyllous species resembles <i>R. saniculifolius</i>, <i>R. peltatus</i>, and the Mediterranean forms of <i>R. baudotii</i>. It differs from the aforementioned species by a combination of characters not found in any of them, i.e., 5–6 mm long petals, up to 2.2 mm long, glabrous achenes with a partly persistent style, a densely pubescent, in fruit slightly elongating receptacle, and intermediate leaves with rigid filiform apical segments, being divided into two or three cuneate, shortly petiolate leaflets. A key to all similar East Mediterranean taxa is presented. DNA analyses based on the sequencing of nuclear, ribosomal Internal Transcribed Spacer (ITS), and two chloroplast noncoding regions (<i>rpl</i>32-<i>trn</i>L and <i>psb</i>E-<i>pet</i>L), complemented by the analysis of genome-wide polymorphism using double digest RAD Sequencing (ddRADseq) supported that <i>Ranunculus dahlgreniae</i> is a distinct lineage, clearly separated from <i>R. peltatus</i>, <i>R. baudotii</i>, and <i>R. saniculifolius</i>. The phylogeny based on ddRADseq resembles the topologies obtained from chloroplast and nrITS data but with increasing resolution and support of fine-scale relationships. Extensive sampling, including taxa from temperate Europe and the West Mediterranean area, as well as the application of reduced-representation sequencing, allowed to better understand the pattern of diversity in the section <i>Batrachium</i>.