However, a preliminary phylogenetic investigation shows that PyrD homologs which are present as a homodimer (PyrD1A) are clearly a derived group within the heteratetramer (Pyr1B) set most closely related to the bacillus group within the firmicutes.
One of them, supported by the presence of a hard secondary venom duct with filaments, consistently shows that Spinariina is actually a derived group within the Rogadini, and thus the subtribal names employed within Rogadini (viz. Rogadina and Spinariina) should be eliminated.
Some have suggested it is nested within a derived group of hydrozoans, the Narcomedusae [ 10- 13] or the cnidarian class Scyphozoa [ 14]; while others have suggested it belongs to a separate cnidarian class, Polypodiozoa [ 1, 15, 16].
In this scenario, chitons are not primitive molluscs but rather a derived group, potentially adapted to high-energy marine shores.
If PylRS was a recent invention within methanogens, one would expect the PylRS protein family to have diverged from another methanogen aaRS protein family, and thus be a derived lineage within known aaRS groups for this clade.
The Acalyptratae is a large, derived group of flies that also contains the families Drosophilidae and Tephritidae.
I now give further evidence that, although not as compelling as the polarizations discussed above, nonetheless also indicates that Gracilicutes are a major derived group within Negibacteria.
Carnotaurus is a derived member of the Abelisauridae, a group of large theropods that occupied the large predatorial niche in the southern Landmasses of Gondwana during the late Cretaceous.
Finally, node G represents the common ancestor of the sordidus species group, which is a derived, monophyletic lineage that evolved within Australia (Table 1, Fig. 1).
Strepsiptera are a morphologically highly derived group of endoparasitic insects whose phylogenetic position was debated for some time, but the most recent and complete studies clearly support a sister relationship of Strepsiptera with Coleoptera (Niehuis et al. 2012; Boussau et al. 2014).
