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

Re: archaic ungulates survive boundary events



> Since "Ungulata" is a polyphyletic group, what does
> this actually
> mean? What, exactly, is _Kharmerungulatum_?

A 2.5 mm lower right molar says Google.

Ungulates polyphyletic - not necessarily so, if you
include cetaceans. Neither hypothesis (Ferungulata vs
Ungulata - basically, horses closer to carnivores vs
horses closer to cows and whales) is exactly robustly
supported and the material evidence is all but
nonexistent.

Whichever hypothesis may be correct, they're all
Laurasitheria, which is interesting in itself.

>From the online supplement:

"VPL/JU/IM/31 exhibits many salient features
characteristic of primitive condylarths. In
general, the trigonid has inclined labial and
subvertical lingual slopes with reduced
trigonid-talonid height difference, precingulid is
weak and bears a distinct cuspule, the
paraconid is connected to the protoconid by a short
posterolabially curved paracristid, the
hypoconid has a concave lingual face and occupies the
labial half of the talonid and is
connected to the hypoconulid by a short crest, the
cristid obliqua meets the trigonid wall
at the posterolabial base of the metaconid, the
talonid basin is poorly excavated and deep
at the anterolingual margin, the talonid groove is
short and obliquely transverse, the
hypoflexid is deep, the entocristid terminates below
the posterolingual base of the
metaconid, and there are no labial, lingual,
posterolabial cingulids. (length of trigonid =
1.50 mm, length of talonid = 0.73 mm, width of
trigoind = 1.6 mm, width of talonid =
1.33 mm)."

"Kharmerungulatum is considered closest to
Protungulatum gorgun (S3, fig.3F) both
sharing a voluminous protoconid closely appressed to a
reduced metaconid, a short and
oblique paracristid joining the oval paraconid with
the protoconid, a paraconid placed
labial to the lingual edge well separated from the
metaconid, and an entoconid
representing the smallest talonid cusp. However, in
Kharmerungulatum, as there are no
labial, lingual and posterolabial cingulids, the
talonid appears relatively shorter and less
wide than in P. gorgun. Baioconodon middletoni (S3,
fig.5F) is also comparable to
Kharmerungulatum in possessing a protoconid markedly
more massive than the
metaconid, a paraconid not appressed to the metaconid,
a weak anterior cingulid, a
talonid narrower and shorter (less inflated) than the
trigonid, and lack of labial and
lingual cingulids. Loxolophus faulkneri (S3, fig.6B)
has a talonid smaller than the
trigonid as in Kharmerungulatum, but differs from the
latter in having a cingulid encircling the crown and a
hypoconulid as the smallest talonid cusp. Baioconodon
and
Loxolophus are comparatively larger in size and have
rugose enamel."


Regards,

Eike


      Heute schon einen Blick in die Zukunft von E-Mails wagen? 
www.yahoo.de/mail