Proposal (18) to
Transfer Psarocolius oseryi to genus Ocyalus or resurrect Clypicterus
Effect on South American CL: transfer of species oseryi from Psarocolius to Ocyalus, or resurrect the monotypic genus Clypicterus.
Background and rationale: see Price & Lanyon (Auk 119: 335-348, 2002). A one-sentence synopsis is that molecular data (2000+ bp of cyt-b) indicate that Psarocolius as often currently defined is polyphyletic with respect to Cacicus, and that removal of oseryi from Psarocolius is the only way to maintain Psarocolius as a monophyletic taxon under our current understanding of the phylogeny of the group. They recommended transfer to Ocyalus, the strongly supported sister taxon to oseryi in their phylogeny.
Discussion: As summarized by Price and Lanyon, the cacique-like characters of oseryi (and latirostris) have long been known; likewise, the differences between oseryi and other oropendolas were noted by those (e.g., Meyer de Schauensee) who recognized the monotypic genus Clypicterus for oseryi. To maintain oseryi in Psarocolius would require inclusion of one or more species of Cacicus in that genus. The Price-Lanyon study is convincing, to me, that this transfer is necessary to maintain monophyletic taxa.
However, as Doug Stotz pointed out, transfer of oseryi into Ocyalus is not the only option. Perhaps the conservative thing to do is resurrect monotypic Clypicterus until the Price-Lanyon results are Cacicus have been published. The paper above sampled only two Cacicus, both in my opinion "weird' ones (solitarius and melanicterus); perhaps inclusion of more "typical" Cacicus, like C. cela, will affect the sister-relationship of oseryi and latirostris.
So, let's make this proposal two-parted:
1 = removal of oseryi from Psarocolius.2 = where to place oseryi:
A = into Ocyalus B = resurrect Clypicterus for oseryi.
Recommendation: I strongly recommend removal of oseryi from Psarocolius. I would also prefer resurrecting Clypicterus, for the reasons above and as pointed out below by Doug.
Van Remsen, 21 May 2002; revised 23 May 2002
Comments from Stotz:
"On oseryi, I have three immediate questions. 1) what about nest architecture? P/O/C. oseryi has a typical oropendula nest I think, rather than the side entrance of Cacicus. I don't know anything about latirostris nests. 2) Given that Cacicus solitarius and melanicterus don't hold together as a group with respect to Ocyalus in the analysis of Price and Lanyon, my question is why weren't more Caciques included, and would that have changed the topology? 3) In terms of morphology does oseryi have any of the oddities that latirostris has that caused it to be placed in a separate genus, and retained there by Ridgely and Tudor for example? I think of it as much more oropendula-like than latirostris."
Comments from Robbins:
"I vote "yes" for removing oseryi from Psarocolius and I believe until we have additional results from Price and Lanyon (hopefully soon) the conservative thing to do is place oseryi in Clypicterus."
Comments from Stiles:
"The removal from Psarocolius seems obvious; I agree that given the doubts regarding Cacicus, resurrecting Clypicterus is the safest course for now. I am not at all sure that Cacicus itself will prove monophyletic, given the considerable variation in nest architecture (among other things), and when those results are in we can return to the generic allocation of oseryi."
Comments from Schulenberg:
"I vote "Yes" to remove oseryi from Psarocolius. Price and Lanyon data leave little doubt.
"The problem then becomes what to do next:
> > (2) resurrect Clypicterus/ merge into Ocyalus.
"From the proposal: "Price & Lanyon (Auk 119: 335-348, 2002). ... removal of oseryi from Psarocolius is the only way to maintain Psarocolius as a monophyletic taxon ...They recommended transfer to Ocyalus, the strongly supported sister taxon to oseryi in their phylogeny"
"I didn't find a reference or recommendation in this paper to putting oseryi in Ocyalus. In fact Price and Lanyon wrote (page 346) "Until a study of cacique phylogeny can be completed, we consider it premature at this time to propose a change in nomenclature." (I get a sense that Scott Lanyon would sooner drink kerosene that recommend a change in nomenclature: 10+years after the fact, Scott still has not dealt with the nomenclatural issues arising from his research showing that Agelaius is not monophyletic.)
"I am happy to retain the monotypic genus Clypicterus for oseryi, with the recognition of the risk that our generic nomenclature for oseryi may change when results are in from a Lanyon et al. phylogeny of caciques."
"Part A yes, the data is clear that oseryi has to be transferred out of Psarocolius. Part B I am not comfortable putting oseryi into Ocyalus, partly due to the fact that the relationships of Cacicus are not clear yet, and due to the fact that oseryi and latirostris are very different beasts. It makes sense to me to resurrect Clypicterus for oseryi.