Hominoid Tooth Confusion and Camel Taphonomy

["Jaime A. Headden" <qilongia@yahoo.com>]

  I was certainly impressed by this issue in the inclusion, not only of the
first dinosaur taxon named in an electronic publication (which the ICZN upholds
as long as there is a physical reposit, in this case a CD in major institutions
and at the Library of Congress ensures physical preservation and reference),
but that there were a wealth of vertebrates also named, not just "species" but
"genera" as well, of many mammals. As noted, this issue honors the late William
Downs, and thus many taxa are named for him.

  Two papers of note impress the use of electronic formats over print for some
purposes, including the graphic quality in Meng et al. with intensive
illustrations, which bring print costs through the roof, and digital appendices
or even detailed quality and size of papers available, as in Polcyn et al. on
*Pachyrachis* (supported as a macrostomatan with the use of CT-data).

  Two papers in there, however, are unusual and useful papers for study. Kelley
offers a perspective on why pig teeth shouldn't be confused with hominoid
teeth, though ironically this is just yet another way pigs are compatible with
man ;). Andrews and Whybrow study over a 15 year period the taphonomy of a
camel skeleton in the Emirate of Abu Dhabi, United Arab Emirates.

  Kelley, J. 2005. Misconceptions arising from the misassignment of
non-hominoid
    teeth to the Miocene hominoid *Sivapithecus*. _Palaeontologica Electronica_
    8(1): http://www.palaeo-electronica.org/2005_1/kelley16/issue1_05.htm

Abstract:
  "Since early in the twentieth century, two distinct upper canine morphologies
   have been assigned to the fossil hominoid *Sivapithecus* from the Siwaliks
of
   Indo-Pakistan. The canine sample as a whole has been critically important in
   conceptions of *Sivapithecus* taxonomy and paleobiology. Some specimens of
   one canine type are associated with other dental and gnathic material of
   *Sivapithecus*, whereas all specimens of the other type occur as isolated
   teeth. One unusual feature of all of the latter specimens is the lack of a
   distal wear facet, even on teeth with an extensive mesial wear facet showing
   that the teeth were in functional occlusion. This condition is never found
in
   the upper canines of extant anthropoids, indicating that the canines of the
   second type have been misidentified as hominoid teeth. Comparisons with the
   canines of other mammals revealed that they are in fact the canines of
female
   suids. Removing these canines from *Sivapithecus* calls into question one
   recent taxonomic revision of the genus that argued for time-successive
   species of *Sivapithecus* based on the perceived temporal segregation of the
   two canine morphologies. It also alters certain perceptions about canine
   sexual dimorphism in *Sivapithecus*."

  Andrews, P. and P. Whybrow. 2005. Taphonomic observations on a camel skeleton
    in a desert environment in Abu Dhabi. _Palaeontologica Electronica_ 8(1):
    http://www.palaeo-electronica.org/2005_1/andrews23/issue1_05.htm

Abstract:
  "A camel skeleton in a desert environment in Abu Dhabi was monitored for 15
   years to record stages of weathering, dispersal, carnivore action and
   trampling in this extreme environment. Weathering was substantially less
   rapid than that recorded in tropical environments, being slower both in
   inception and in later development. Skeleton dispersal was mixed, with a
core
   group of ribs and vertebrae remaining close to the death site, but
individual
   bones being traced for up to 60 m and many disappearing altogether.
   Scavenging took place, and the size of tooth marks indicated foxes and
   jackals. Trampling was the major source of breakage of bones, most of which
   were too robust for small carnivores like foxes and jackals to break."

  The need for both papers is a caution and a test of what we know. Obviously,
the axiom is held true: Science marches on. Observing modern taphonomy where
nothing but wind and scavenging occurs is useful in observing taphonomy in
similar burials much older in time. How not to confuse teeth is the importance
of the other paper.

  Cheers,

Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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