The Coal Measures Amphibia of North AmericaMoodie, Roy Lee
Science
The Coal Measures Amphibia of North America
Moodie, Roy Lee
Amphibians, Fossil -- North America; Paleontology -- Carboniferous; Paleontology -- North America
_Mandible._--It has been possible to study both sides of the mandible.
The left ramus was preserved in the coal, with its inner face exposed.
This face is broken by two large oval openings, the internal mandibular
foramina. This is the term used by Reynolds for the openings on the inner
surface of the alligator jaw. So far as I can ascertain, no other known
labyrinthodont mandible displays this character in such a marked degree.
Dr. Branson has figured in _Anaschisma browni_ Branson from the Triassic
(49) of Wyoming the inner surface of the left ramus, on which there are
likewise two openings but differently situated. A similarity between the
two mandibles is observed in that the suture separating the prearticular
and angular touches the posterior edge of the posterior foramen.
Several of the sutures are well preserved and they have been indicated
in the drawing (fig. 42). The pillar separating the two foramina is cut
by the suture separating the angular and prearticular very much as in
_Anaschisma_, with the difference that in the latter form the angular
and prearticular are not approximated. I believe I detect the suture as
represented separating the anterior end of the angular from the dentary
and splenial. I am assured of the portion near the anterior foramen and
also of the part near the tip of the ramus. This shows the angular to be
a very elongate element, running very nearly the entire length of the
mandible, much as in _Anaschisma_ and other labyrinthodont genera. The
splenial is a small, slender element located farther forward, where it
has been shoved by the large-sized internal mandibular foramina. The
prearticular is a rather long, broad element, of which only a portion is
preserved. I am not sure as to the location of the suture for the dentary,
unless it is represented by the line bounding the roughened area near the
teeth. If this is true, the dentary is a large element, since it extends
well down upon the outer side of the jaw. The dentary possesses evidences
of 26 teeth, a few of which are completely preserved. Most of them are,
however, represented either by bases or by impressions in the coal. The
teeth are very similar to those of the maxilla, though slightly larger.
The characters given for the maxillary teeth will suffice for those of the
dentary.
[Illustration: Fig. 42.
A. Outer view of mandible of _Eobaphetes kansensis_ Moodie, from
the Coal Measures of Washington County, Kansas. Original in U.
S. National Museum. × 0.33. Cat. No. 6680. _a_, angular; _r_,
articular; _d_, dentary.
B. Portion of skull of _Eobaphetes kansensis_ Moodie, from the Coal
Measures of Washington County, Kansas. Original in U. S. National
Museum. Cat. No. 6699. × 0.33. Lateral-line canal represented by
heavy broken line, _n_, nasal; _m_, maxilla.
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