Integrative taxonomy (IT) is becoming a preferred approach to delimiting species boundaries by including different empirical criteria. IT methods can be divided into two types of procedures both of which use multiple kinds of evidence: step-by-step approaches test hypotheses by sequential evaluation in a hypothetic-deductive framework, while model-based procedures delimit groups based on statistical information criteria. In this study we used a step-by-step approach and a Gaussian clustering (GC) method to test species boundaries in the northernmost species of the Liolaemus montanus group. We used different methods based on mitochondrial and nuclear DNA sequence data, morphological measures and niche envelope variables. In contrast with GC, our step-by- step approach shows that one Andean population (Abra Apacheta) previously considered part of L. melanogaster, is actually nested within another clade; another Andean species, L. thomasi, is equivocally shown to be either a distinct species or conspecific with L. ortizi; and an additional Andean population (Abra Toccto) is delimited by concordance among most lines of evidence and different methods as a distinct lineage. However, one of the oldest and low-elevation populations (Nazca) is strongly delimited by all data sets and IT procedures as a new lineage distinct from any currently recognized species.
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© 2016 The Linnean Society of London.