Fig. 4

Phylogenetic relationships and outgroup dependence among the four major myriapod subgroups. a on the left: schematised relationships derived from ML tree inference with IQ-TREE among the myriapod subgroups when including only Chelicerata and Onychophora in STRICT amino acid data set while excluding Pancrustacea (STRICTaa_ChO). Statistical bootstrap support was inferred from 100 non-parametric bootstrap replicates; on the right: results of the AU test of five alternative trees (in blue: trees derived from quartet topology A, in red: trees derived from quartet topology B, the tree marked with ** is the tree proposed by Fernandez and colleagues [2] and supported by morphological evidence (see [3]). Note that two variants of Hypothesis B1 exist that differed by the placement of Scolopendromorpha, Lithobiomorpha and Geophilomorpha within centipedes. Hypothesis A1 and A2 (derived from quartet topology A) were not rejected while all others were rejected (p < 0.05). b on the left: schematised relationships derived from ML tree inference of our STRICT amino acid data set with IQ-TREE among the myriapod subgroups with Pancrustacea as the sole outgroup (Chelicerata and Onychophora excluded). Statistical bootstrap support was inferred from 100 non-parametric bootstrap replicates; on the right: results of the AU test of five alternative trees (in blue: trees derived from quartet topology A, in red: trees derived from quartet topology B (Fig. 1). **: see a. Hypothesis A1 and A3 (derived from quartet topology A) were not rejected while all others were rejected (p < 0.05)