Monday, May 28, 2007

Bird of the Day: Solomon Islands Frogmouth

Blogging on Peer-Reviewed ResearchA new Frogmouth (Podargidae) has been described just this April from the Solomon Islands (Cleere et. al. 2007). What makes this finding especially unique, is that a reanalysis of Solomon Islands subspecies (inexpectatus) of the Marbled Frogmouth (Podargus ocellatus), found in Australia and New Guinea, revealed not just that it deserved to be split, but that it warranted a whole new genus. Thus, the Solomon Islands Frogmouth Rigidipenna inexpectata was described.

The University of Florida's press release is here (including links to the discoverer's pages).

The paper is here (you probably need a journal subscription to access). Here is the abstract.

Source: Cleere et. al. 2007

The complex, confused history of the taxonomy of this group is described:

As was common in the 19th century, subspecies of Podargus ocellatus were originally described as full species, with P. inexpectatus the last to be named (Hartert 1901). A few years later, Mathews (1913) placed P. marmoratus in a poorly defined new genus (Micropodargus) that was said to differ from Podargus only in its much smaller size and stronger bill. Without explanation, Mathews (1927) subsequently treated six taxa, including marmoratus and inexpectatus, as races of ocellatus within Micropodargus. Peters (1940) treated Micropodargus as a synonym of Podargus, which has remained the sole genus for all Papuan–Australian–Oceanic frogmouths to the present day. (Cleere et. al. 2007 pg 274)

The authors also explain the difficulties in assigning their outgroups for osteological and molecular work, because the placement of Podargidae in Caprimulgiformes is questioned. One interesting note is the fossil presence of three extinct genera of Podargids, as well as "the oldest fossils assigned to the Nyctibiidae, Steatornithidae and many other currently tropical families of birds also are from early Tertiary deposits in the temperate Northern Hemisphere (Olson 1987, Mourer-Chauviré 1989)." (Cleere et. al .2007 pg 277).

The molecular basis for new genus placement is this phylogeny:
Source: Cleere et. al. 2007

This phylogeny alone does not necessarily warrant a split from Podargus (although it is a deep split from the rest of Podargus, it still forms a monophyletic clade), but combined with distinct, unique morphology, and distinct call notes more like Batrachostomus than Podargus, indicate that the new genus is justified.

All of this is technical systematics stuff that, while interesting to me, may not be interesting to the lay birder. Taxonomists and systematists get a lot of flak from others. This Birdforum thread, about an Economist article, showcases those viewpoints:

The day taxonomists say "Right, that's it, we've got it all sorted out!" they instantly negate their continued role as taxonomists. So we can expect infinite flux in this field, in order to keep taxonomists in jobs. (Post #23)
I agree it's a pseudo science. (Post #24)

The thread is actually a decent debate about splitting, but takes too much of the viewpoint that taxonomists do this out of species bias, rather than practicing a real science. The case of Rigidipennis clearly illustrates when an evaluation of a subspecies' status, a common event these days (and often maligned as birds get lumped and split and back again with new research), reveals incredible insights. Taxonomists aren't in it to keep their jobs, they're in it because we have barely begun to understand even the birds we thought we knew.

NIGEL CLEERE, ANDREW W. KRATTER, DAVID W. STEADMAN, MICHAEL J. BRAUN, CHRISTOPHER J. HUDDLESTON, CHRISTOPHER E. FILARDI, GUY DUTSON. 2007. A new genus of frogmouth (Podargidae) from the Solomon Islands - results from a taxonomic review of Podargus ocellatus inexpectatus Hartert 1901. Ibis 149 (2), 271–286.

No comments:

Post a Comment