Proposal (627) to South American Classification Committee
Move Pelecanoididae in linear sequence
This is a minor proposal to move the Pelecanoididae to follow the Procellariidae in our linear sequence of families. Currently our sequence is DIOMEDEIDAE, PROCELLARIIDAE, HYDROBATIDAE, PELECANOIDIDAE.
Here is our current footnote:
1. The monophyly of the family, consisting of a single genus, has never been questioned. Livezey and Zusi (2007) treated them in their own suborder, as sister to all other Procellariiformes. However, genetic data (Nunn & Stanley 1998, Cracraft et al. 2004, Ericson et al. 2006) indicate that they may be embedded within the Procellariidae, as suggested by Cracraft (1981). Hackett et al. (2008) found a strongly supported sister relationship between the Pelecanoididae and Procellariidae, but with very limited taxon-sampling. Proposal needed to change linear sequence of families. Christidis and Boles (2008) and Cracraft (2013) included them within the Procellariidae without even subfamily rank.
Analysis and Recommendation: There seems to be no question that Pelecanoides is either close to or embedded within the Procellariidae, and I was tempted to propose merger with Procellariidae. However, published data on this are few, where to place them within the Procellariidae is uncertain, comprehensive data are likely on their way soon, and better to err on the side of conservatism. Thus, this is likely just a stopgap proposal to minimally move them to adjacent positions in our linear sequence.
Van Remsen, March 2014
Note: if the genetic data are correct, then this is yet another example of the failure of cladistic analyses of morphological characters (Livezey-Zusi reference) to recover phylogeny. In the hand, diving-petrels strike me as small Puffinus shearwaters specialized on diving.
Comments from Stiles: ÒYES, although given the virtually unanimous genetic evidence, I would not be averse to including Pelecanoides in the Procellariidae, tentatively following Puffinus or as a subfamily.Ó
Comments from Nores: ÒYES. However, the inclusion of these birds in Procellariidae, although possible, seems premature.Ó
Comments from Zimmer: ÒYES, recognizing that more tweaking (i.e. placement within Procellariidae) is likely coming soon.Ó
Comments from Pacheco: YES. A tiny provisional measure, but perfectly adjusted to the present knowledge.Ó