Proposal
(687) to South American Classification Committee
Merge Pelecanoididae into Procellariidae
Effect
on SACC:
This would remove the family Pelecanoididae from our classification and place
the genus Pelecanoides as Incertae
Sedis within the Procellariidae.
Background: Our current footnote under Pelecanoididae is
as follows:
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. SACC proposal
passed to change linear sequence of families. Christidis and Boles (2008) and Cracraft
(2013) included them within the Procellariidae without even subfamily
rank. Prum et al. (2015) found that Pelecanoides was embedded in the
Procellariidae. SACC proposal badly needed.
As
can be seen in proposal 627
that changed the linear sequence of families to reflect a close relationship
between Pelecanoididae and
Procellariidae, we’ve really just been waiting for sufficient genetic data to
make this change. I
New
information:
Prum et al. (2015) sampled 1 albatross (Phoebastria
nigripes), 3 storm-petrels, 3 shearwaters (Fulmarus glacialoides, Puffinus
griseus, Pterodroma externa) and
1 diving-petrel (Pelecanoides urinatrix),
and found that the diving-petrel was sister to Pterodroma externa with strong support and was more closely related
to that species than either was to Fulmarus
glacialoides or Puffinus griseus. Here is a section of their Fig. 1:
Analysis
and Recommendation:
Of course better taxon-sampling will be needed to resolve the relationships of Pelecanoides within the Procellariidae,
but it is clear that it is just a procellariid adapted for diving form the
surface, and that over-emphasis on associated morphological adaptations has led
to its placement as a separate family.
As noted in the SACC footnote, two major sources have already eliminated
family rank for Pelecanoides and
placed it as just another genus within the Procellariidae. I strongly recommend
following that treatment. I recommend
placement of Pelecanoides at the end
of the linear sequence of genera, Incertae Sedis, until additional analyses
reveal its relationships within the family.
Van Remsen, October
2015
=========================================================
Comments
from Stiles: “YES, a
long-overdue change, as genetic data firmly place Pelecanoides in the Procellariidae.”
Comments
from Jaramillo: “YES –
although I am not happy about it. I liked the idea of the diving-petrels as
this oddball and very different group of tubenoses being a family. However,
when you see a very small shearwater, like Little Shearwater, the fact becomes
clear that their very alcid-like look and flight style is more a function of
small size and large body than anything all that unique about them. Small
shearwaters essentially link the flight style and fast flapping style of the
diving-petrels to larger and longer-winged tubenoses.”
Comments from Stotz: “YES Makes me sad,
but not a surprising result.”
Comments
from Zimmer: “YES. The genetic data are clear. Alvaro’s comments about the smallest
shearwaters presenting a morphological bridge between diving-petrels and
larger, longer-winged tubenoses are spot-on.”
Comments from Robbins: “YES. Genetic data clearly indicate that Pelecanoides is embedded within the
Procellariidae.”
Comments from Pacheco: “YES. Pertinent
proposal to further analysis that reveals their relationships within
Procellariidae.”