[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Phorusrhacos “wrinkle bearer (jaw)”: Etymology and Meaning



Ben Creisler <bcreisler@gmail.com> wrote:

> The article in La Nature theorized that the giant birds may have
> coexisted with the last of the dinosaurs in South America during the
> Cretaceous and actively preyed on them, likely contributing to their
> extinction!


The idea isn't as off-the-wall as it first sounds.  There is a report
of a possible phorusrhacoid from the Late Cretaceous of Antarctica.
Or at least some form of cursorial bird, based on an isolated femur
from the Lopez de Bertodano Formation (although not from the same
level that yielded _Vegavis_ and _Polarornis_).  The femur *might* be
from a cariamaform (even a phorusrhacoid, see below), and the Lopez de
Bertodano Formation has been dated to the end of the Cretaceous (I
don't know how confidently - see Dyke & van Tuinen, 2004).


In any case... large, cursorial, predatory neornithean birds such as
phorusrhacoids might well have been around at the end of the
Cretaceous, up to (and beyond) the end-K catastrophe.  If so, these
birds could have preyed upon small non-avian dinosaurs in the
aftermath of the impact, and therefore helped hasten the extinction of
the survivors.  You never know.



Case J., Reguero M., Martin J., and Cordes-Person, A. (2006). A
cursorial bird from the Maastrictian of Antarctica. Journal of
Vertebrate Paleontology 26 (3): 48A.

"A left femur from the early Maastrichtian, Cape Lamb Member of the
Lopez de Bertodano
Fm. on Vega Island, Antarctic Peninsula, shows striking similarities
to modern cursorial
predatory birds of South America (Seriemas, Cariamidae) and of Africa
(Secretarybirds,
Sagittariidae). The size of the Antarctic femur is nearly identical to
those of both modern
bird families and thus the Antarctic specimen would be about the same
size, at around a
meter in height. The crucial features in demonstrating the habit of
this Maastrichtian bird
are: the enlarged and posteriorly prominent tibiofibular crista; the
laterally expansive lateral
epicondyle; and the highly planar and vertically oriented fibular
trochlea. These apomorphic
features are present in the modern yet unrelated cursorial birds and are equally
developed in the Antarctic specimen. Considering the proximal femoral
features, the biogeographical
location and the presence of phororhacoids in the Eocene of Antarctica, then
this specimen may represent a taxon which may be ancestral to both cariamids and
phororhacoids or it is the basal cariamid which is then ancestral to
the phororhacoids, rather
than being their descendant."