I continue to be skeptical about hyraxes. With the extant cape hyrax
being less high than the aardvark or elephants in the myoglobin the
authors correlate with amphibious habits, I cannot figure out why they
decided to rate extinct hyraxes, whose myoglobin is no longer
available for testing, so high.
If you can deduce it from the following passage, you are doing better
than I did with my first read:
____________________________________________
An amphibious ancestry of hyraxes may appear surprising; however, past
hyracoid diversity was much richer than indicated by the three small-
bodied (<5 kg), strictly terrestrial genera of today, as illustrated
by the at least two times larger Pliohyrax kruppii and the 390-kg
Kvabebihyrax kachethicus from the Pliocene (2 to 5 Ma), for which
semiaquatic lifestyles have been proposed as long as a century ago
(39, 40). Recent isotope evidence has further indicated a possible
semiaquatic lifestyle for the late Eocene (37 Ma) Thyrohyrax meyeri
and another, as yet unnamed, new hyracoid genus of similar age (34).
The reconstruction of a high ZMb value in a hyracoid ancestor is not
affected when ancestral sequence reconstruction is based on
alternative phylogenetic hypotheses, such as hyraxes rather than
sirenians comprising the sister group to proboscideans (41). This and
recurrent gigantism [e.g., rhinoceros-sized Titanohyrax ultimus (42)]
calls for a reassessment of the lifestyle of other fossil hyraxes that
have previously been considered unambiguously terrestrial (37).
___________end of excerpt
from
http://www.sciencemag.org/content/340/6138/1234192.full
On top of everything else, I don't see how all this bears on the
putative common ancestor of ca. 65 milllion years ago.
I won't have time to really study the large file of supplemental
material for a good while -- the next three weeks are going to be
mostly quality time with my family, and I'll be taking a posting break
starting the middle of next week.
Anyway, here is the url for it; maybe it isn't paywalled [I can't tell
from here--I can access _Science_ in full from here] and someone else
can give us the lowdown on hyraxes.
http://www.sciencemag.org/content/suppl/2013/06/12/340.6138.1234192.DC1/Mirceta.SM.pdf
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://www.math.sc.edu/~nyikos/
nyikos @
math.sc.edu