A New Order of Fishlike Amphibia From the Pennsylvanian of KansasEaton, Theodore H. (Theodore Hildreth)
Science
A New Order of Fishlike Amphibia From the Pennsylvanian of Kansas
Eaton, Theodore H. (Theodore Hildreth)
Amphibians, Fossil; Paleontology -- Pennsylvanian
The ethmosphenoid, which we cannot identify, may have been exposed in a
gap between the premaxillary and the palatine. The gap measures
approximately 8.0 mm. wide and ranges up to 1.0 mm. anteroposteriorly.
The maxillary begins at a suture with the premaxillary lateral to the
naris and continues posteriorly, bordering the orbit with a width of
about 1.2 mm. It then tapers to a point approximately 2.0 mm. anterior
to the lateral projection of the pterygoid. The width of the maxillary
at this point is 0.8 mm. and the posterior end is broken; probably when
complete it approached the pterygoid, and either met the latter or had
a ligamentous connection with it. As nearly as can be determined, the
total length of the maxillary is approximately 12.0 mm.
The teeth on the maxillary are small and seem to be in two longitudinal
rows. The palatine bears two large, grooved teeth anteriorly; the first
is approximately 1.0 mm. posteromedial to the naris and the second is
about 3.0 mm. posterior and slightly lateral to the naris. The flat
ventral surfaces of the palatine and pterygoid bear numerous small
teeth distributed as shown in Fig. 4.
_Braincase and Occipital Region_ (Fig. 5)
The parts of the neurocranium are scattered, disconnected and
incomplete, but it is possible to make out a number of features of the
otico-occipital section with fair assurance. In posterior view the
notochordal canal and foramen magnum are confluent with each other, and
of great size relative to the skull as a whole. The notochordal canal
measures 2.8 mm. in diameter, and the foramen magnum about 4.0 mm. The
crescent-shaped supraoccipital rests on the upright ends of the
exoccipitals, but between the latter and the basioccipital no sutures
can be seen. Probably the whole posterior surface of the braincase
slanted posteroventrally; consequently the rim of the notochordal canal
was about 3.0 mm. behind the margin of the parietals.
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