canal, the mandibular bones and axial limb bones,
are unchanged from the condition normal for the Rhipidistia, but most
other characters are of amphibian grade. To express these facts
taxonomically requires that _Hesperoherpeton_ be removed from the
family Cricotidae, suborder Embolomeri, order Anthracosauria, and
placed in a new order and family of labyrinthodont Amphibia.
Order PLESIOPODA
(_plesios_, Gr., near, almost; _podos_, Gr., foot)
Labyrinthodontia having limbs provided with digits, but
retaining posterior flanges on axial bones as in
Rhipidistia, without joint-structure at elbow and wrist
essential for terrestrial locomotion; neurocranium having
separate otico-occipital section, large notochordal canal,
no occipital condyle, as in Rhipidistia; nares separate from
rim of mouth; pectoral girdle anthracosaurian; vertebrae
having U-shaped intercentrum and paired, but large,
pleurocentra.
Probably associated with the characters of the order, as given above,
are the connection of pectoral girdle with skull, and the presence of a
tympanic membrane, the stapes functioning in both sound-transmission
and palatoquadrate suspension.
Family HESPEROHERPETONIDAE
Orbits and foramen magnum unusually large in correlation
with reduced size of animal; squamosal forming posterior
margin of orbit; circumorbital series absent (except for
postorbital); sensory pits on squamosal and frontal.
Characters defining the family are evidently the more specialized
cranial features, which probably evolved during Mississippian and early
Pennsylvanian times.
The definition of the genus and species may be left to rest upon
Peabody's (1958) original description and the present account, until
the discovery of other members of the family gives reason for making
further distinctions.
SUMMARY
_Hesperoherpeton garnettense_ Peabody (1958), based on a
scapulocoracoid and part of a vertebra, was originally placed in the
order Anthracosauria, suborder Embolomeri, family Cricotidae. A new
skeleton from the type locality near Garnett, Kansas (Rock Lake shale,
Stanton formation, Upper Pennsylvanian), shows that the animal has the
following rhipidistian characters: Large notochordal canal below
foramen magnum, otico-occipital block separate from ethmosphenoid,
postaxial processes on three axial bones of forelimb, pectoral girdle
(probably) articulated wit
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