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NEW AND LITTLE KNOWN GENERA AND SPECIES OF
VERTEBRATES FROM THE LOWER PERMIAN

OF OKLAHOMA

EVERETT C. OLSON

TIM Ubnry cf ttit

JUL 11970

Univtftrty of IHinoit
FIELDIANA: GEOLOGY « UfHn«-Ch*n^l«n

VOLUME 18, NUMBER 3

Published by

FIELD MUSEUM OF NATURAL HISTORY

APRIL 17, 1970

GEOLOGY LIBRARyC

I

NEW AND LITTLE KNOWN GENERA AND SPECIES OF
VERTEBRATES FROM THE LOW ER PERMIAN

OF OKLAHOMA

EVERETT C. OLSON

Professor of Zoology
University of California, Los Angeles

FIELDIANA: GEOLOGY

VOLUME 18, NUMBER 3

Published by

FIELD MUSEUM OF NATURAL HISTORY

APRIL 17, 1970

PUBLICATION 1090

Patricia M. Williams

Editor

Library of Congress Catalog Card Number: 73-119157

PRINTED IN THE UNITED STATES OF AMERICA
BY FIELD MUSEUM PRESS

NEW AND LITTLE KNOWN GENERA AND SPECIES OF
VERTEBRATES FROM THE LOWER PERMIAN

OF OKLAHOMA'

INTRODUCTION

In the course of studies that led to a report on "Early Permian
Vertebrates from Oklahoma" (Olson, 1967) large collections of fishes,
amphibians and reptiles were made. Parts of these are now housed
in the Stovall Museum at The University of Oklahoma, and others
are at Field Museum of Natural History in Chicago. In general,
allocation of specimens has been made so that collections from par-
ticular sites and particular horizons are located in one place.

As noted in the cited publication, specimens representing both
new genera and species were found in the course of the work. Re-
view of older materials showed that some additional information
upon previously described but very poorly known genera was at
hand. The present report is devoted to description and discussions
of some of these materials.

Thorough analysis of the wealth of fragmentary materials from
the Orlando site undoubtedly will reveal specimens that will eventu-
ally require description. Other studies, to be published separately,
are also in progress. Among these are an analysis of the lungfish
Gnathorhiza serrata (Cai'lson, 1968, and in press); studies of Crossto-
telos, also by K. J. Carlson; a study of the brain case of Labidosauri-
kos meachami, by William MacLean (in press) ; a study of a new.
puzzling, procolophonian reptile from near Grandfield, by Eleanor
Daly (1968); and a study of the vertebrates associated with this
specimen, also by Miss Daly.

The present paper treats specimens from three important sites:
\ Orlando; Perry site 6, about 9 miles northwest of Perry; and a site

' This study was supported by National Science Foundation grants GB2543
and GB7070X.

359

360 FIELDIANA: GEOLOGY, VOLUME 18

in the Hennessey formation, just south of Norman. Each of these
was described briefly in Olson (1967).

CRICOTILLUS BRACHYDENS CASE AND

PLEURISTION BRACHYCOELOUS CASE

FROM ORLANDO, OKLAHOMA

The Orlando Deposits

About two miles northeast of Orlando, Logan County, Oklahoma,
in the SE I4 sec. 31, T. 20 N. R. 1 W. occurs one of the oldest known
sites of early Permian vertebrates in Oklahoma. Case (1902) de-
scribed a collection from this site and since then various parties have
collected additional specimens. For the most part, specimens are
fragmentary and occur in sandy ironstone nodules. They have been
collected from surface concentrations that have formed as the gray
shale in which the nodules are formed has weathered. The concen-
tration in the parent bed is so low that attempts to get material by
excavating it have had little success.

This locality was described in some detail earlier (Olson, 1967),
and a measured section was presented. It lies in the Wellington for-
mation about 100 feet below the contact of the Wellington and the
Garber formations.

A full restudy of the collections from this site is in order, but this
is a major project which will not be completed for some time. The
two genera that are the subject of this study, however, can be treated
at present. Both have been carried in the literature since their first
description by Case (1902) with sporadic mentions and suggestions
on relationships, but almost without any additional study. Much
can now be done to supplement descriptions and to fix the relation-
ships of the two genera more closely. This is the purpose of this
report.

Cricotillus brachydens Case

History

In 1902, Case described very briefly two amphibians, Triynero-
rhachis leptorhynchus, a new species, and Cricotillus brachydens, a new
genus and species. Later Case (1911) dropped T. leptorhynchus as
indeterminate, but suggested that it might belong to Cricotillus
hrachydeyis. Except for a listing of T. leptorhynchus in Case (1915),
this specimen, KU 350, has dropped out of the literature.

OLSON: PERMIAN VERTEBRATES IJGI

Cricotillus hrachijdens was named on the basis of a specimen,
KU 349, that consisted of a pair of teeth-ljearing bones, accom-
panied by two other smaller pairs of bones (PI. I). The specimen,
which is about an inch long, was called part of a skull by Case (1902)
and this has not been questioned. As w ill be shown, however, this
determination cannot be correct, and the specimen appears to repre-
sent a portion of a pair of lower jaws.

Case made no familial assignment of the genus in his 1902 de-
sci-iption, but inasmuch as its description follows that of Cricotus
directly in sequence and the name Cricotillus was given, he appears
to have recognized affinities with Cricohis. Case (1911) placed the
genus in the family Cricotidae and listed it similarly later (Case,
1915, 1946). Romer (1966) gave a tentative reference to the family
Cricotidae as well.

Under this determination, Cricotillus hrachydeus is considered to
be an embolomerous amphibian generally related to Cricotus of the
Pennsylvanian and, perhaps more closely, to Archeria of the Early
Permian. The only dissent from this placement is found in a casual
remark by Williston (1910a) to the effect that Cricotillus probably
l)elonged to Crossotelos, an amphibian generally assigned to the Nec-
tridea. close to Diplocaulus, but only very remotely related to the
embolomeres.

In the course of the study of collections of the Lower Permian
beds of Oklahoma, the holotypes of Trimerorhachis leptorhynchus
Case and Cricotillus brachydens were borrowed from the Paleonto-
logical Museum of The University of Kansas to aid in identification
of other Orlando materials. Nothing that can be definitely assigned
to Cricotillus has been found, but it is possible that full preparation
of some of the material in various collections will e\entually reveal
other specimens.

Description

Original description: Case's (1902) original descrijAion w liic-h has
remained unchanged in later publications, was as follows:

"A fragment of rostrum indicates the presence of a new genus and
species of amphibian. The fragment is from the middle portion of
the maxillaries between which appear in the posterior half the ante-
rior parts of the naslas (sic), and on the lower surface the vomers.
The upper surface of the maxillaries is sculptured by low longitudinal
ridges, especially on the ui)per suiface. The maxillary is triangular
in section, the upper surface is convex and the inner or vomei'inc side

362 FIELDIANA: GEOLOGY, VOLUME 18

and the dentigerous surface are flat or slightly concave. The inner
and lower surfaces meet in a very sharp ridge. The vomers are very
narrow but of considerable vertical extent and lie closely apposed to
the vomerine sides of the maxillary; they project as sharp ridges on
the lower sides of the skull. The teeth are represented by the roots
alone, their chief characteristic is the relative breadth of the roots,
approaching in this respect the Diadectidae. They are from two to
three times as wide as long. The tooth line is somewhat concave in-
wardly following the curve of the maxillary bone and the teeth are
ankylosed to the flat dentigerous surface.

Measurements:

Total length of the fragment (about half the

length of the head, probably) 030 m.

Width of anterior end 015 m.

Width of posterior end 021 m."

Discussion ayid revised descriptions: The specimen was figured to
show the dental surface by Case (1911, 1946). The drawing, while
reasonably accurate, shows little detail and does not show the fea-
tures of the opposite side, which are hard to reconcile with the inter-
pretation that this is a portion of the maxillaries. Photographs are
included in Plate I of this paper.

Case's description, if the names of the bones are omitted, is fairly
accurate. If, however, Case's identifications are used, the situation
is morphologically untenable. Nasals are presumed to wedge in be-
tween the maxillae and to terminate some distance posterior to the
end of the maxillae, leaving no place for contact with nares, unless
these be considered to have lain far back and out of contact with the
premaxillae. If the maxillae of Case are considered premaxillae it is
remotely possible that this specimen might represent a very elongated
region anterior to the narial openings into which the nasals pene-
trated. No parallel, however, is to be found among any of the known
amphibians. Even if this improbable situation is granted, the pre-
sumed vomer-maxillary arrangement of the palate is an impossible
one. The vomers would then be closely appressed splints in a very
narrow snout and the internal nares must have lain somewhere far
back, after considerable lateral expansion had occurred. But a pas-
sage between the external nares and internal nares is impossible
under this interpretation unless premaxilla, maxilla, vomerine are
modified in a way unlike that in any other known tetrapod.

OLSON: PERMIAN VERTEBRATES 363

A much simpler interpretation is that the two teeth-bearing ele-
ments are dentaries, that the medial bones are the splenials and that
the wedges between the dentai'ies, the ti'iangular bones, are post-
splenials. This also does not produce an entirely usual situation, for
the supposed splenials do not appear at the ventral margin of the
lower jaw and the contact of the splenials and postsplenials is not
broad; but only a slight modification of the conditions found in vai-i-
ous labyrinthodonts is necessary to produce this condition. U ap-
pears much more reasonable to assume that such a change took place
than to require the major reorganization necessary to interpretation
of this fragment as part of a skull.

Case's suggestion (1911) that the specimen he first called Trimero-
rhachis leptorhynchus, KU 350, might pertain to Cricotillus brachy-
dens appears to be well founded. If the type of C. brachydens is
considered to be from the lower jaws, then the two rami appear to
make a nice extension of the lower jaws of the skull and jaws of
KU 350. The type of C. brachydens, however, is from a somewhat
larger individual. In Figure 1, a cross-section from the posterior end
of the jaw in C brachydens, KU 349, and one from the anterior end of
the jaw in KU 350 are shown diagrammatically. The latter lies just
at the level of the anterior termination of the postsplenial, whereas
the former is a short distance farther back in the jaw. Some overlap
of the two specimens does occur. The positions of the two sections
are indicated in the reconstruction of the jaw. Figure 1.

Case made special note of the teeth of C. brachydens, in particular
of the transverse breadth of the base of the crowns. The teeth are
rather badly preserved, but their essential condition is well shown in
Plate I. Teeth in KU 350 also are not well preserved. One lower
is present and this shows a transversely wide base and a simple, some-
what recurved, conic crown. In both specimens the teeth are anky-
losed to a broad, slightly concave dorsal sui'face of the lower jaw.
On the basis of the teeth, assignment of the two specimens to the
same genus and species is certainly reasonable.

The skull, KU 350, is in a poor state of preservation. U is shown
in Plate I, but photographs do not differentiate bone and matrix well.
Semi-diagrammatic drawings in Figure 1 make this distinction and
a reconstruction is given in Figure 1. The lower jaws have been
rotated somewhat mediodorsally and are pressed into the skull in
such a way that the palate cannot be prepared. Much of ihe pre-
orbital region is missing.

364

FIELDIANA: GEOLOGY, VOLUME 18

Fig. 1. Skull and jaws of Cricotillus brachydens Case. A, lateral view; B, dor-
sal view; C, reconstruction of jaw; D, reconstruction of skull; E, section of jaw at
anterior end of jaw in K. U. 350; F, section of jaw at posterior end of K. U. 349,
lying slightly posterior to section in E. All based on K. U. 349 and K.U. 350.
A-D X 1.0. Abbreviations for all figures are given on page 424.

The general pattern of the bones of the skull as far as it can be
made out conforms more or less to that found in a variety of laby-
rinthodonts. The narrowness, of course, is a feature found only in
a few genera. The parietals are long and the postparietal is fairly
prominent. The pineal lies far forward in the parietal in a somewhat
unusual position. In Figure 1 a small, splintlike bone, identified as
supra temporal, is shown on the right side of the parietal platform, ly-
ing behind a poorly preserved element identified as intertemporal.
The element called supratemporal appears to be a distinct bone and
not merely the result of a crack in the parietal. However, it should
be noted that it is not evident on the other side of the skull.

A small part of the posterior part of the platform is missing and
there is a suggestion that "horns" were present. It is assumed, as
shown in Figure 1, that the tabular was present but has been almost
completely lost. If the interpretation is correct the tabular was in
contact with the parietal and, if it was present as seems highly likely,
the position and proportions of the postparietal make this interpre-
tation mandatory.

OLSON: PERMIAN VERTEBRATES 365

The orbit is only partly preserved on one side and the small size
showTi in the restoration may be an exaggeration. The circumorbital
bones are present on three sides, but missing anterior to the orbit, as
shown in the reconstruction. The temporal series, however, is badly
preserved and not entirely clear. It appears that three temporal
elements were present, as in the reconstruction, but this, as noted,
is somewhat conjectural.

The suspensorium of the lower jaw slanted sharply postero-ven-
trally from the area of the otic notch and the jaw articulation was
well back of the parietal table. Between the table and the more ven-
tral elements was a deep otic notch. The depth in the reconstruction
may be excessive, due to exaggeration by crushing of the specimen.

Relationships

On the basis of what he considered skull but what is here consid-
ered lower jaw, Case (1902, 1911. 1946) assigned Cricotillus either
tentatively or positively to the Family Cricotidae. The evidence
was clearly insufficient. The skull, assigned to the genus and species
in this paper, and as suggested earlier by Case (1911), adds some use-
ful information. Much is now available that was not to be seen
earlier, since additional preparation has been carried out. The skull
pattern very clearly is that of a labyrinthodont amphibian. The
two commonest amphibians in the Orlando collections are Diplo-
caulus and Crossotelos. The skull of Diplocaulus is, of course, very
well kno\Mi, but this is not the case for Crossotelos. The vertebrae
of Crossotelos are very similar to those of Diplocaulus, although read-
ily distinguishable on the basis of the transverse processes, and this,
among other features of the postcranium, strongly indicates that
Crossotelos, like Diplocaulus, is a nectridean, as has been generally
accepted. Williston's (1910a) suggestion that Cricotillus hrachydens
is referable to Crossotelos is thus untenable.

All other references have been to the Cricotidae, but with very
little more basis than that supplied by Case. Actually, the assign-
ment was based upon the presumed elongation of the rostrum of the
skull and the fact that embolomerous, Cr/co/«s-like centra, occur at
Orlando. The skull, KU 350, adds weight to this assignment. If it
has been properly interpreted, the full temporal series of intertem-
poral, supratemporal and tabular was present. The tabular appears
to have been in a position in which contact with the parietal was
inevitable.

366 FIELDIANA: GEOLOGY, VOLUME 18

The otic notch appears to have been very deep and this, in con-
junction with the temporal elements, strongly suggests anthracosaur
affinities. Within this group, relationships are quite clearly with the
embolomeres rather than the seymouriamorphs.

In many respects Cricotillus resembles Archeria and the question
as to whether they are congeneric can be raised. Most definitive in
differentiation are the teeth, for the lower teeth in KU 349 are dis-
tinctive, as Case noted, and not matched by those in specimens of
Archeria from the Permian of Texas. A slight broadening of the
bases is found in some of the more posterior teeth of the upper jaw
in some specimens of Archeria, but in none is the extreme condition
of Cricotillus approached. Also, it would seem from the material
available, that Cricotillus was somewhat more elongated and nar-
rower, particularly in the rostral region, than Archeria. The conditions
of preservation, however, argue for caution in any such interpreta-
tion. Minor features of the pattern of skull bones and the position
of the parietal appear to be different in Cricotillus and Archeria. For
these reasons, it is concluded that Cricotillus is a distinct genus.

Formal Systematics

In view of the above considerations it is now possible to formalize
the systematics of the genus and species, which has not been done
previously, as follows:

CLASS AMPHIBIA

Subclass Labyrinthodontia

Order Anthracosauria

Suborder Embolomeri

Family Cricotidae

Cricotillus Case

Diagnosis. — A small, narrow-skulled cricotid amphibian. Parietal
long, narrow, and with pineal opening far forward. Otic notch deep.
Teeth: slightly recurved crowns and transversely broad bases, width
ranging from 2 to 3 times basal length. Teeth ankylosed to broad,
slightly concave surface on dentary and maxillary. Splenial not ex-
posed along ventral margin of jaw, but rising to flank dentary tooth-
bearing surface medially.

Cricotillus brachydens Case

Holotype. — KU 349, part of a pair of lower jaws.

OLSON: PERMIAN VERTEBRATES 367

Horizon aiul locality.- Wellinoton Formation, lower Permian, 100
feet below Wellington Garber contact. Fi'om two miles northeast of
Orlando, Logan Comity, Oklahoma, SE '., sec. 31. T. 20 N.. R. 1 W.

Diagnosis.- — Same as for genus.

Referred specimeu. — KU 350. Partial skull and lower jaws. Hori-
zon and locality same as for holotype. Obtainable measurements as
follows :

mm.
Overall length of skull as preserved, from the posterior

end of suspensorium to region just anterior to orbit . 52.0

Length of parietal along midline suture 21.0

Width of parietal, maximum 15.0

Length of Interparietal along median suture 4.5

Distance from posterior end of parietal along

midline to posterior margin of parietal bone 14.0

Pleuristion brachycoelous Case
History

This genus and species was described by Case (1902) on the basis
of vertebrae from the Orlando site. Two specimens were involved.
These are now in the collections of the University of Kansas under the
single number KU 351. Case did not designate one or the other as
the holotype and used both in his description. One comprises three
vertebrae of an adult and the other several vertebrae and some limb
elements. Both appear to pertain to the same species, but the speci-
men with three vertebrae is adult and the other subadult or juvenile.
In the section of formal systematics, following the descriptions, the
adult specimen is designated as the holotype and the other is consid-
ered to be a referred specimen.

Pleuristion has received little attention since it was established,
and what attention has been given apparently has not involved any
serious re-examination of the Kansas specimens. Case (1907) placed
it tentatively in the Pelycosauria, but said also that it might pertain
to Bolosaurus, a genus which itself poses some taxonomic pi'oblems.
In this publication he figured one of the three vertebrae of the adult
specimen, KU 351 (PI. 1, figs. 14, 15).

In 1911 Case (p. 14) included Pleuristion in an unnamed family
under Incertae sedis in the amphibian suborder Temnospondyli. No
explanation is given, but since the designation follow^s family Gym-

368 FIELDIANA: GEOLOGY, VOLUME 18

narthridae, it may be that the common confusion resulting from
similarity of form of microsaurs and captorhinomorphs, to which
Pleuristion quite certainly pertains, was involved. Williston (1910c)
noted that Pleuristmn was the smallest Permian reptile and made
comparisons with Araeoscelis. He figured a humerus that he felt
belonged to the genus and made the remark that a number of speci-
mens of the genus, from Texas, were in the collections of the Amer-
ican Museum of Natural History. Since no designation of the source
or number of the figured specimen was given and since the original
materials lack any vestige of a humerus, the reference cannot be con-
firmed or denied.

In 1916 Williston (1916) gave the following citation: "Pleuristio7i
Case. — Vertebrae and humerus of the Captorhinus type, all that are
known. Oklahoma."

Von Huene (1925, p. 249, fig. 28) revived the pelycosaur designa-
tion of Pleuristion. Romer and Price (1940) noted that vertebrae
and a skull existed and stated that affinities were clearly with the
cotylosaurians. Romer (1956, p. 494; 1966, p. 364) placed the genus
in the family Captorhinidae. Although a skull was mentioned by
Romer and Price (1940), no information on it has been published.
The skull undoubtedly is one so designated in the collections of Field
Museum of Natural History formerly at Walker Museum. FMNH
UC 676 (formerly UC 676) carried the label of Pleuristion and is, as
far as I know, the only prepared skull of this type from Orlando.

Description

Case (1902) gave the original description of Pleuristion hrachy-
coelous as follows:

"Pleuristion hrachycoelous, gen. et sp. nov.; Several series of small
vertebrae of characteristic form indicate the presence of a new form
whose position is somewhat doubtful. They are chiefly character-
ized by the union of the parapophyses ad (sic) diapophyses in a broad
winglike transverse process, and by the peculiarly broad and large
neural canal. The centra are proportionately very broad and the
bottom line is devoid of sculpture and with no trace of a keel. The
vertebrae are deeply amphicoelous. The neural spine is low and the
zygapophyses are relatively large and with flat faces. In some the
neural arch seems to be co-ossified with the centrum and in others it
is separated. The transverse process is broader above and becomes
narrower below where it curves forward to touch the anterior edge of
the centrum. There is no evidence of the presence of an inter-centrum.

OLSON: PERMIAN VERTEBRATES 369

Measurements:
Breadth across transverse processes 0095 m.

Height from base of centrum to top of neural
spine Oil m."

This description as it stands hardly serves to separate these verte-
brae fi'om those of various captorhinomorphs and it is somewhat
difficult to find an adequate basis for the later assignments to the
pelycosaurs.

Associations of the specimens: The two specimens of KU 351 ap-
pear to be the basis for this description, although no designation is
made in the paper. These are herein designated as 351a, the adult
specimen of three vertebrae and 351b, the immature specimen. The
latter includes 11 identifiable vertebrae, with possible fragments of
others, some rib fragments, an immature femur, and some phalangeal
elements. Both specimens are illustrated in Plate II.

In addition to these specimens the skull and partial jaws (fig. 2),
FMNH UC 676 and a partial skeleton OUSM 3-0-S19 appear to per-
tain to this genus and species. Associations are based upon the re-
semblances of the vertebrae and features of the other parts of the
skeleton that differ from those of Captorhinus, the only other known
captorhinomorph from this site. Association by vertebrae poses
something of a problem since variation of form along the column is
fairly extensive, as shown in OUSM 3-0-S19. Figure 3 shows verte-
brae from KU 351a and OUSM 3-0-S19 from approximately the
same part of the column, with that of the latter being somewhat
more posterior in the presacral series. The resemblances are evi-
dent. The vertebrae also resemble those of Captorhinus fairly closely,
differing somewhat in the proportionate height and width of trans-
verse processes. Some details of the postcranium of OUMS 3-0-S19
brought out in the descriptions that follow tend to confirm these
somewhat tentative differences of the vertebrae.

The skull, UC 676, is rather badly damaged and has been dis-
torted so that the right side has been much shortened. Some post-
cranial elements have been pressed into the posterior part of the skull.
These include vertebrae, two of which ai'e shown in Figure 3F and G.
Once again these are distinctly Captorhinus-Mke. In view of the poor
preservation, it is doubtful that the available measurements can be
shown to exceed the range of comparable measurements of the genus
Captorhinus.

370

FIELDIANA: GEOLOGY, VOLUME 18

i-

Fig. 2. Pleurisiion brachycoelus Case. Skull and jaws based on FMNH
UC 676. A, skull as preserved, somewhat diagrammatic; B, reconstructed skull;
C, lower jaw to show teeth. All X approx. 1.5.

In spite of the poor preservation of the skull, there can be no
question that it is not Captorhinus on the basis of the dentition.
This being the case, inasmuch as only two captorhinomorph genera,
Captorhinus and Pleuristion, have been found in the extensive col-
lections from Orlando, it is reasonable to assume that the skull, which
is that of a captorhinomorph, is in fact Pleuristion. This is the inter-
pretation that is made in this paper.

The skull: Much of the information on the skull is presented in
Figure 2A, B, and C, and in Plate II. It all comes from UC 676.
The restoration is based on both sides of the skull, with the propor-
tions taken from the left side. Overall length is between 35 and
38 mm. along the midline, from snout to the end of the parietal plat-
form, and the distance from the tip of the snout to the posterior end
left quadrate is 41 mm.

The bone of the temporal area is badly damaged on the right side,
with the squamosal missing. The upper portion of the squamosal is
present but the base is missing. In spite of the damage, it seems
nearly certain that there was no temporal fenestra, although the
presence of a small one cannot be definitely ruled out.

OLSON: PERMIAN VERTEBRATES 371

The dentary and maxilla are very slender in proportion to their
lengths, considerably more so than in Captorhinus. Each carries but
a single row of teeth, rather than the multiple rows found in Capto-
rhinus. These teeth, however, are very different in form and wear
patterns from the rather blunt and somewhat chisel-like teeth of
Labidosaurus. The fourth and fifth maxillary teeth are long and
robust, with the third smaller, and the first very small. Back of the
fifth tooth there is a rapid reduction in length. Twelve teeth are
pi-esent in the maxilla of UC 676 and probably only three or four
more were present on the posterior part of the maxilla, which is miss-
ing. Only the smallest fragments of premaxillary teeth are present,
the premaxillae being completely destroyed. These fragments sug-
gest that the teeth were rather small, in contrast to Capforhinus, but
the evidence is far from conclusive.

The lower teeth (fig. 2C) consist of a very slender first tooth, two
long, robust teeth, a gap, and then several smaller teeth. The first
is about one-half the length of the third tooth, and there is a gradual
decrease posteriorly from the third. This is not gi'eatly different
from the condition in the front part of the jaw of Captorhinus and
Labidosaurus.

Although the palate is badly mashed, it is possible to identify the
two pterygoids. The element has a very strong transverse flange.
The posterior part of it is set with relatively strong teeth, in-egularly
arranged. On either side of the interpterygoidal vacuity, the ptery-
goids carry a strong patch of palatal teeth arranged in a series of four
fairly regular rows. These appear to be much more fully developed
than in comparable specimens of Captorhinus and Labidosaurus.

Vertebrae and ribs: The ribs are holocephalous throughout and are
slender, without expanded shafts. The vertebrae, as shown in Fig-
ure 3, are generally similar to those of Captorhinus, with broad
arches, unicipital transverse processes and relatively short neural
spines. Case defined the genus on the basis of vertebrae, but made
no comparisons with those of any other animals. He stressed the
broad, open neural canal and the broad plate-like transverse proc-
esses. Both features are evident, but they are only slightly modified
from the conditions found in specimens of Captorhinus of comparable
size. Measurements in Table 1 bear on this point.

The vertebrae of KU 351a, which were the pi-incipal basis of
Case's description, are from the anterior part of the presacral col-
umn, an area in which broad, flat transverse processes occur in the

l^

Table 1. — Postcranial measurements of specimens of Pleuristion

brachycoelous Case.

Femur i^max P.W. D.W.

OUSM 3-0-S19

right 21.9 ... 8.2

left 22.0 7.2

KU 351b

right 16.5 5.8 6.2

Fibula

right 13.0* ... 4.5

Vertebrae Cw c, Ht. Wazp Wppz Wtvp Wnc

OUSM 3-0-S19

ant. ps 3.8 4.0 5.0 ... 5.1 7.1 3.0

mid. dor 4.8 ... 5.8 5.3 6.3

sacral 3.1 ... 5.0* ... 4.0 ... 3.0

UC 676

ant. ps. (1) 3.5 4.0 5.8 ... 5.6* ... 3.1

ant. ps. (2) 3.5 ... 4.9* 8.5 3.0

KU 351ai

ant. ps. (1) 4.2 3.6 5.8 ... 4.3 10.1 3.6

ant. ps. (2) 3.4 3.3 5.6 ... 4.4 10.8

ant. ps. (3) 3.6 3.0 6.0 3.4*

KU 351b

sac. reg 2.1

mid. dor 2.3

* Approximate

1 These vertebrae, although listed as anterior presacrals (ant. ps.) are farther
forward in the column than others so listed.

Abbreviations:

ant. ps., anterior presacral

Cw, maximum transverse width of centrum

Ci, maximum ventral length of centrum

D.W., maximum distal width

Ht., height from base of centrum to base
of neural arch

^max, maximum length

mid. dor., mid-dorsal vertebra

P.W., maximum proximal width, for femur
at level internal trochanter

sac. reg., in vicinity of sacrum,
position not certain

Wazp, width anterior zygapophyses,
outer margin to outer margin

Wnc, posterior width neural canal

Wppz, width posterior zygapophyses,
outer margin to outer margin

Wtvp, maximum width transverse
processes, outer margin to outer
margin

372

Fig. 3. Pleuristion brachycoelous Case. Postcranial elements. A, vertebrae
of holotype, K. U. 351A, anterior; B, vertebrae of holotype, K. U. 351A, posterior;
C, Vertebrae of holotype, K. U. 351 A, lateral; D, mid-dorsal vertebra of OUSM
3-0-S19; E, sacral, 1st presacral and 1st caudal; F, vertebra of FMNH 676, lateral;
G, mid-dorsal vertebra of FMNH 676, dorsal; H, scapulocoracoid of OUSM
3-0-S19, lateral; I, fibula of OUSM 3-0-S19; J, femur of KU 3.51B, dorsal; K, fe-
mur of OUSM 3-0-S19, distal end, dorsal; L, femur of OUSM 3-0-S19, ventral.
All vertebrae approx. X 2.0; femora and fibula approx. X 1.5; scapulocoracoid
X 1.25.

373

374 FIELDIANA: GEOLOGY, VOLUME 18

captorhinomorphs. Thus this feature is in some large part an expres-
sion of the position in the column. Here, and in the more posterior
parts as well, however, the transverse processes are very prominent
and do appear to be somewhat more strongly developed than in
Captorhi7ius. A major problem, however, comes from the fact that
the extent of variation in Captorhinus is not known.

Captorhinus has two sacral vertebrae (Case, 1911, fig. 43, p. 98;
Fox and Bowman, 1966). OUSM 3-0-S19 has the sacrum well pre-
served with both presacral and postsacral vertebrae in articulation
(fig. 3E). There is but a single sacral vertebra, with the rib of the
first postsacral directed sharply backward, and that of the first pre-
sacral slender, long and recurved. The iliac head is slightly displaced
in the specimen, but there seems no question of the interpretation
that only one sacral rib articulated with it.

Intercentra are prominently preserved in the mid-dorsal part of
the column and probably were present throughout. The ribs did
not articulate with them, in the areas in which the intercentra are
present in OUSM 3-0-S19.

Limbs and girdles: Most of the information comes from OUSM
3-0-S19 and KU 351b. The well preserved elements are illustrated
in Figure 3. The scapulocoracoid has no features that are recogniz-
ably different from those found in this complex in Captorhinus. A clav-
icle is present in UC 676, but this too is not distinctive. The only
remains of a humerus consist of partly concealed distal ends, which
show no distinctive features. Some carpal or tarsal elements are pres-
ent in KU 351b and metapodials and phalanges are present in this
specimen and in OUSM 3-0-S19. In both, the elements are sufficient-
ly displaced that no details of the composition of the feet can be deter-
mined. The shapes and proportions are those characteristic of small
captorhinomorphs. Ungual phalanges were narrow and claw-like.

The tip of the iliac blade and part of the pubo-ischiadic plate are
present in OUSM 3-0-S19, but neither is well exposed. In this speci-
men, however, the right and left femora are well preserved and be-
tween them show most of the features of this bone. As evident in
Figure 3C, the bone has a general Captorhinus cast, but is short,
stout and set with strongly developed trochanters and ridges. The
internal trochanter is very strong, the fourth trochanter moderate,
and the adductor ridge prominent. The distal condyles are strong
and set well apart. An immature femur is present in KU 351b as
illustrated in Figure 3 J. It shows no special features. The femur
of Pleuristion, in the general shape and development of its processes,

OLSON: PERMIAN VERTEBRATES 375

is very similar to that of Captorhiuus, but appears to be slightly dif-
ferent in some of the features noted from the well presei'ved femora
of C. aguti fi'om the Oklahoma, Richard's Spur, fissure fills.

Parts of some of the lower limb elements of the fore and hindlimb
are present, but for the most part they are not well shown. Much
of a fibula is present (fig. 31) and it appears to be indistinguishable
from the same bone in Captorhinus.

Relationships

Very clearly. Pleuristion is a member of the family Captorhinidae,
as Romer (1956, 1966) has indicated. In this family it is very close
to Captorhinus in most of its features. Some of the proportions of
the bones of the postcranium probably will differentiate the two, but
in the absence of a good estimation of the variation of structure in
the genus Captorhinus a positive statement to this effect is not pos-
sible. The vertebrae of the holotype do appear to be distinctive in
the width of the transverse processes (see Table 1), and this is to
some degi-ee reflected in the other assigned specimens. The femur
appears to be somewhat distinctive as well. The dentition of the
skull. UC 676, is the most definitive feature, with the single row of
maxillary and dentary teeth. This is, of course, matched in Lahido-
saurus, but the tooth form of Pleuristion is more like that of Capto-
rhinus than of Labidosaurus. The palatal teeth are more fully de-
veloped in Pleuristion than in either of the other two genera.

Taking the various features into consideration, one must, it ap-
pears, agi-ee that this is a genus separate from Captorhinus. The
dentition suggests that it is adapted to a somewhat different diet.
There is no question, however, that the two genera are very closely
related.

Formal Systematics

CLASS REPTILIA

Subclass Anapsida

Order Captorhinomorpha

Family Captorhinidae

Pleuristion Case

Diagnosis.— A small captorhinid reptile close to Captorhinus. dif-
fering principally in the presence of but a single row of maxillary and
dentarv teeth. Fourth and fifth maxillary and second and thii-d den-

t-

376 FIELDIANA: GEOLOGY, VOLUME 18

tary teeth long, robust, and sharp. About 15 teeth in each jaw.
Maxilla and dentary both long and slender.

Anterior presacral vertebrae with broad, plate-like unicipital
transverse process. Only a single sacral vertebra. Femur with
strong condyles, trochanters and ridges, with adductor ridge prom-
inent. Measurements as in Table 1.

Pleuristion brachycoelous Case

Holotype. — KU 851a. Three anterior presacral (cervical) verte-
brae. One of two specimens used by Case in his original description
(Case, 1902, p. 67) and the one figured by Case (1907, PI. I, figs. 14

and 15).

Horizon and localihj. — Wellington formation, 100 feet below Wel-
lington-Garber contact. From two miles northeast of Orlando, Logan
County, Oklahoma, SE }i sec. 31, T. 20 N. R. 1 W.

Diagnosis. — Same as for genus.

Referred specime7is. — KU 351b, 11 intercentra, femur, foot ele-
ments, fragments of ribs of an immature individual. One of two
specimens used by Case in his original description (Case, 1902).
OUSM 3-0-S19, a partial skeleton, lacking skull, in a single nodule.
FMNH UC 676, a skull, partial lower jaws, several vertebrae, clav-
icle and fragments of other postcranial elements. Horizon and local-
ity of all referred specimens same as that of the holotype.

A NEW ARAEOSCELOID REPTILE FROM THE
WELLINGTON FORMATION

Introduction

Among the sites listed in Olson (1967) is Perry site 6 (SEli SE^
sec. 26, T. 23 N, R. 2W.) in Noble County. The "insect" beds lie
near the base. A measured section (see Olson, 1967), is repeated in
Table 2. The lower part consists mostly of alternating thin dolo-
mites and shales, but bed 16 is a highly varied yellow, red and gray
shale that carries plants and vertebrates, and beds 18 through 21
consist of a series of sandstones and shales, capped by a thin dolo-
mite. Beds, 18, 19 and 21 also carry vertebrate remains and have
yielded the reptile which is the subject of this report.

These uppermost beds, as discussed briefly in the cited paper,
appear to have originated in a lake, very near to shore. Some of the

OLSON: PERMIAN VERTEBRATES .377

Table 2.- Measured Section at Perry Site fJ.
(from Olson, 1967)

Thickness
Bed Description (feet)

21 Argillaceous, gray dolomite; hones 0.7

20 Deep gray shale 0 . -

19 Red sandstone, medium to coarse; bone, conchostracans 1.6

18 Black to maroon shale 4.0

17 Yellow shale 3.0

16 Lenticular yellow, gray to red fo.ssiliferous shale, with sandstone
lenses to 3 feet in thickness. Limonitic with selenite crystals.

Vertebrates and tree trunks, fronds, leaves, seeds 10.0

1 5 Blue-gray shale 1.0

1 4 Red sandstone 1.0

1 3 Gray shale 1.6

1 2 Gray dolomite 0.7

1 1 Red shale, nodular at top 2.0

1 0 Dolomite and shale in thin alternating layers 1.0

9 Gray shale 2.0

8 Gray dolomite 0.1

7 Gray shale 1.8

6 Red shale 1.1

5 Impure gray dolomite 0.4

4 Red nodular shale 0.6

3 Gray, dolomitic shale 0.9

2 Gray shale 5.0

1 Gray dolomite 0.9

vertebrate remains come from varied lenses of sandy shale which
were formed in shallow swales on the lake bottom. Others are found
rather widely scattered in an overlying i"ed sandstone and a few
specimens have been found in the capping dolomite.

Several hundred bones have been recovered, mostly from the len-
ticular sandy shales where they occur in close packed concentrations
(PI. III). Most of these pertain to the new reptile described in this
paper, but some are bones and scales of a rather large platysomid fish,
and scraps of amphibians and other reptiles. The platysomids occur
in greater concentrations in very fine grain, dark lenses of silt in which
few reptile bones are found.

All of the bones are disarticulated, even those of the skull. It has
been necessaiy to reconstruct the i-eptile described here tVom these
individual elements. Foitunately, one specimen in the dolomite, de-
noted later as the holotype, was a partially ai'ticulated individual
which provided basis for assignment of many of the isolated elements.
It has been rather badly damaged by gi-ound water action, and some
of the bones are preserved only as mold.s. The skull in the dolomite
specimen is not well preserved and this has made it necessary to re-
constmct the skull from isolated elements. Since these i-epresent

t-

378 FIELDIANA: GEOLOGY, VOLUME 18

individuals over a wide size range, difficulties in determining propor-
tions of the various skull regions exist. The fact that skull elements
of the large platysomid are also present in the deposits has left open
the possibility that some of these have been mistaken for bones of the
reptile. These problems are discussed further in comments on the
reconstruction of the skull and the descriptions of its salient features.

CLASS REPTILIA

Subclass Euryapsida

Order Araeosceloidea

Family Uncertain

Dictybolos new genus^

Diagnosis. — Overall length about 25 to 30 inches for fully grown
adults. Skull bones thin, lacking surface sculpture and possessing a
fine canal structure which reached the surface in small circular pores.
Frontal lacking median suture. Nares set well back from anterior
end of snout. Dentary long and slender with anterior end slightly
reflected ventrally. Marginal dentition consisting of 25 to 30 teeth
above and below. Teeth with sharp, recurved terminal ends, with
enamel finely fluted distally. Basal portions with deeper fluting and
broadened longitudinally.

Vertebrae with broad, flat zygapophyses and slightly expanded
arches. Neural spines moderately developed, centra deeply amphicoe-
lous. Ribs with expanded shafts, heads partially double to holoceph-
alous. Limbs and girdles poorly ossified, with no osseous attachments
of scapula to coracoid, or ilium to pubis and ischium. Scapula very
short and broad, and recurved posteriorly. Ilium with strong, broad,
dorsal caudal process. Limb elements relatively slender with very
thick cartilaginous caps. Tarsals and carpals apparently unossified;
metatarsals and metacarpals long and slender. Phalangeal elements
short and broad.

Dictybolos tener new species

Holotype.-~FMNU UR 1041. Partial skeleton in dolomite, in-
cluding some elements as molds. Part of skull and jaws, vertebral
column, girdle and limb elements.

Horizon and locality. — Wellington Formation, bed 21 of section,
Table 2. Perry site 6 (Olson, 1967), about nine miles northwest of
Perry, Logan County, Oklahoma, SE34 SEM sec. 26 T. 23 N, R. 2 W.

' The name, meaning fisher, has been given because of the presumed habits
of this new reptile as a semi-aquatic, fish-eating creature.

OLSON: PERMIAN VERTEBRATES 379

Diagnosis. — As for genus.

Referred specimens. — A large number of specimens have been re-
ferred to this genus and species and are important in the descriptions.
They have come from beds 18 and 19 of section at Perry site 6 (Olson,
1967). These materials consist almost entirely of isolated bones and
no assemblage into individuals has been possible. Thus many of the
specimens in the list that follows are composites which include the
same elements from many individuals. Specimens that have been
figured have been given separate numbers and those that have con-
tributed to a composite reconstruction of an element in the figures
have in some instances been grouped under a single numbei*. The
specimens are listed in Table 3.

Conditions of occurrence. — Some aspects of the occurrence are im-
portant to an understanding of the descriptions, in particular of
assignment of the separate elements to a single species. Except for
the holotype all the bones are separate, although they occur in pro-
fusion and closely packed in some small lenses of matrix. There is
no sound evidence that the assemblages of bones pertain to one indi-
vidual, and in many cases the size range definitely precludes this
possibility.

Bones occur under three circumstances. The best preserved oc-
cur in the red sandstone, bed 19 of the section. In this bed, however,
they are widely scattered. The condition of these bones is excellent;
they are essentially unmineralized and uncrushed. Although some
moderate concentrations occur in sandstone, there is no evidence that
the clustering has any relationship to life associations. Overlying
the red sandstone and separated from it by a bed of unfossiliferous
black shale is the thin dolomite from which the type specimen has
come. Although there is little crushing of the bones in the dolomite,
preservation is rather poor, due largely to recent action of ground
water.

By far the greatest concenti'ation of bones occurs in small lenses
that lie just under the red sandstone, in bed 18 of the section. These
lenses were formed in shallow depressions on the surface upon which
the red sandstone was deposited. They run from two to five feet in
diameter, and are roughly ovoid in shape. The rock is a heterogene-
ous mixture of sandy shale, shale, sandstone, and masses of mud
which are rich in organic remains. It appears to have been foi'med
by deposition within an active zone of waves which sorted the con-
tents of the small depressions. These are quite comparable to the
mucky masses of sediment and organic remains found in weedy hot-

Table 3. — A list of specimens of Di

ctybolos tener new genus and species.

1041, holotype, part of skull and

1104, phalanges

skeleton

1105, humerus

1042, ilium

1106, ilium

1043,

pterygoid

1107, scapula

1044,

dentary, radius, etc.

1108, caudal vertebra

1045,

mid-dorsal vertebra

1109, nasal

1046

anterior dorsal vertebrae

1110, radius

1047,

pterygoid

1111, scapula

1048

part of scapula

1112, ilium

1049

humerus

1113, prefrontal

1050

right ischium

1114, quadratojugals, identity uncer-

1051

dentary

tain, may be platysomid

1052

lumbar vertebra

1115, jugal

1053

pubis

1116, anterior caudal rib

1054

cervical vertebra

1117-18, fibula

1055

-58, premaxilla

1119, radius

1059

sacral vertebra

1120, ?tibia

1060

anterior caudal vertebra

1121, lacrimal

1061

radius

1122, frontal, part.

1062

?interc]avicle

1123-24, postfrontal

1063

, femur and tibia

1125, frontal

1064

quadratojugal, parts of post-

1126, caudal rib

cranium

1127, anterior dorsal rib

1065

?femur

1128, foot elements

1066

scapula coracoid

1129, ulnae, poor

1067

, maxilla, vertebra, rib, part limb

1130, coracoid

bone, skull fragments

1131, skull parts and fragments

1068

scapula

1132, premaxilla

1069

slab, many bones

1133, cervical rib

1070

squamosal

1134, premaxilla

1071

teeth

1135-37, femur

1072

ilium

1138, dorsal rib

1073

part skull, caudal vertebra

1139, partial rib

1074

, ilium

1140, skull parts and vertebra

1075

, cervical vertebra and rib

1141-42, prefrontal

1076

, base of pelvis

1143, ribs

1077

, postorbital

1144, miscellaneous vertebrae

1078

, postorbital

1145-52, maxilla

1079

, 2 caudal vertebrae

1153, 9 partial maxillae

1080

, skull plates, various

1154-63, dentary

1081-84, fibula

1164, incomplete dentaries and teeth

1085-92, femur

1165, partia tibia and fibula

1093, partial femora

1166-69, humerus

1094-97, radius

1170, ulna

1098-1100, ulna, partial

1171, frontal

1101, parts of about 30 vertebrae

1172, dentary

1102, 6 partial limb bones

1173, various skull bones

1103

, about 30 miscellaneous and

partial limb bones

380

OLSON: PERMIAN VERTEBRATES 381

toms of lakes today, and it is believed that the conditions of (lei:)osi-
tion are comparable in the two cases.

Some of these lenses have high concentrations of bones, with the
new reptile predominant ])ut with I'emains of other reptiles, some
amphibians, and fish, making up as much as 5 per cent of the total.
The matrix appears to have been highly compressible and the con-
tained vertebrate remains are always severely crushed. These pock-
ets are much the most prolific source of bones, but the crushing has
limited their morphological value. Most of the reconstructions are
based upon bones from the red sandstone, but concepts of size range
and abundance have come largely from the remains in the lenses.

The bed below the sandstone, of which these lenses make up the
topmost part, is predominantly a dark, red to brown, sandy shale.
In its upper part it also carries some lenses of very fine, chocolate
colored sandy shale, with verj^ fine sand and some mica. In these
lenses occur remains of partially complete bodies of a platysomid fish
that probably was about 6 inches in total length. Scales of this
fish are found associated with the reptile remains and, it appears,
some of their skull bones are also in the reptile-bearing deposits. The
type of scale, which is found in direct association with the partially
intact bodies of these platysomids, is identical with that found with
the reptiles and no other scales of fish have been found in these de-
posits. Associated with one specimen of platysomid is a partial skull.
This shows the skull bones of this fish to have been highly pustulose
and ornamented. In the reptile-bearing lenses a few such sculptured
bones have been found, and these are considered to be platysomid.

These associations and interpretations have considerable bearing
upon the reconstructions of the skull of Dictybolos. These have been
made from single bones and the positions in the skull determined
from characteristics of the bones and the ways that they appear to fit
together. It is quite possible to confuse fish and reptile skull plates
in such a process. The fact that the skull bones of the platysomids
are pustulose and sculptured is of great use, since all of those consid-
ered to be reptilian lack an}^ sculpturing. The absence of evidence,
exclusive of the skull, of any other large fish, suggests that the bones
without sculpture are non-fish. Some bones of tetrapods, other than
those referred to Dictybolos, are present in the deposits, hut these
have charcteristic features of well known genera of amphibians.
Thus, all of the non-sculptured bones have been considered as per-
taining to Dictybolos and used in reconstructions of the skull. As

I-

382 FIELDIANA: GEOLOGY, VOLUME 18

noted in specific consideration of the skull, there are rather specific

textural and histological features that strengthen this assumption.

Description. — Dictybolos differs markedly from any other reptile

known from the Lower Permian, so that there is no evident basis for

fR

MX

^v'"''

'"2.

i^\^ TF

SQ

■■■'^*>»

JU

=> QJ

Fig. 4. Restoration of the skull of Dictybolos tener n. g. and sp. in lateral
view. The reconstruction is based on single skull elements from many individuals
of different sizes. Hence the proportions may be somewhat off. The elements
used are listed under the bone names in Table 3.

using comparisons in description. Superficially it appears somewhat
like Mesosaurus and Stereosternum, but no close morphological re-
semblances actually exist. Some of the features resemble those of
Araeoscelis, but clearly the two were adaptively very different. The
morphology of the new reptile can best be portrayed by illustrations.
The figures and drawings in the plates, made by Tibor Perenyi of
Field Museum, are rather detailed, and will serve as the basis for
short descriptive comments upon the principal structures.

1. The Skull and Jaws: A lateral view of the skull is shown in
Figure 4. It is, as already noted, based entirely upon individual
bones. Some parts are quite reliable, whereas others are less so.
No bone that could be identified as a parietal has been found, al-
though it is quite possible that such bones are present and have not
been recognized. Several small paired median elements are in the
collections, but they are sculptured and seem not to pertain to the
reptile. The depth of the skull is probably essentially correct, for
there are good guides in the premaxilla, maxilla and orbit.

The premaxilla and maxilla are known from many specimens and
their form and the dentition associated with them are completely
reliable. The nares are set well back from the end of the snout,
shown well by the notch in the posterior end of the long premaxilla
in a number of specimens. On the palate the right and left premax-
illae are joined by a suture for their full length. The maxilla is a

OLSON: PERMIAN VERTEBRATES 383

long, slender element. Other features of the facial and orbital region
are well shown on a number of elements in which the narial and or-
bital margins ai'e developed. All of the elements had broad marginal
overlaps with adjacent bones and none are joined by interlocking
sutural contacts. It would appear that there may have been con-
siderable movement between the various elements.

The frontal, as interpreted, is a peculiar bone in that it is single,
not paired. This is based in particular upon the bone in the holotype
(FMNH UR 1041), but support comes from several other specimens
of the same bone. Clearly there does exist a large, median bone with
a well-finished, concave margin. It cannot be a parietal, since its
structure is inappropriate, and hence by elimination, it has been in-
terpreted as frontal.

The temporal opening is indicated as lying above the junction of
the postorbital and squamosal, giving a euryapsid cast to the skull.
Of the related elements, the postfrontal poses the most problems.
The small, somewhat quadrilateral bone shown in the restoration has
been so placed because it has about the right dimensions and a pair
of finished edges. There are several of these in the collections. The
position, however, is somewhat odd and this designation is one of the
more questionable ones. The dorsal margin of the temporal opening
has not been determined, in view of the lack of an identified parietal.

The postorbital and squamosal offer no particular problems, but
the quadratogjugal is based on rather slender evidence, mostly on
one small element. Other somewhat similar bones are present, larger
and more robust, but they do not show the usual texture of the bones
associated in the reptile skull, and may pertain to the platysomid.

In the collections are two or three presumably cranial elements
which have not been placed in the skull, and these may represent
some of the palatal elements. One median bone may be a para-
sphenoid, but its margins are not well preserved, and it may also be
a stemmed interclavicle. The only identified palatal bone is the
pterygoid (PI. IV). Two representatives have been found. This is a
fairly "normal" primitive reptilian pterygoid, set with a median and
lateral cluster of teeth. It was suturally joined to the palatine and
appears to have made a very open contact with the basipterygoid
process of the basisphernoid.

No elements of the brain case have been found in the deposit.
It may be that these were poorly ossified and hence not well pre-

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384 FIELDIANA: GEOLOGY, VOLUME 18

served, or it may merely be that they were not present in the sample
that has been studied.

All of the dermal elements are thin, lightly constructed, and char-
acterized by a network of canals that run more or less parallel to each
other along the long axes of the bones. They issue to the surface
either as small, round pores, or in shallow channels. These seem to
be vascular in nature and would appear to have brought a large sup-
ply of blood to the surace of the skull, presumably to the skin. What
functional significance they may have had is obscure.

2. Dentition: The marginal teeth (fig. 4, PI. IV) are distinctive
in form, attachment to the jaw, and in surface features. In lateral
aspect they appear to be long, slender, slightly recurved teeth, but
the lower portions are relatively broad transversely. The long axis
is not completely normal to the jaw but slants posteriorly from the
outer to inner margin, with an angle of about 80 degrees to the longi-
tudinal axis of the jaw.

The teeth are not set in sockets, but rest, firmly attached, on the
jaw margins. Cleai^ly tooth replacement took place, for there are
unfilled spaces and different sizes of teeth along the tooth row. The
dental lamina, however, appears not to have been enclosed in bone,
for no evidence of replacement teeth has been found in the jaws. At
the front and back margins of some of the teeth are small, sharp den-
tine spurs which are rather closely appressed to the crown margins.
The nature of these is uncertain and they are currently being studied
as a part of a thorough histological investigation of the dentition and
jaws by William MacLean.

The more distal parts of the crown are covered by a thin enam-
eloid substance which is to varying degrees marked by a complex
grooving or fluting. Superficially, this gives the appearance of a
labyrinthine structure, but it is confined to the enameloid material
and not impressed on the underlying dentine. More basally, espe-
cially on the anterior and posterior flanks of the crowns, there is a
more regular, deeper fluting, not closely connected to that on the
enamel. Both of these features are unique and require more study
of their detailed histology for interpretation.

The gross features of the dentiton of Dictyholos are distinctive and
not matched by any other reptiles of their time or, as far as I am
aware, by any other reptiles at all. Combined with the very long
jaws, they provide a feeding apparatus that is distinctly aberrant
among those known from the lower Permian of North America, but
which has a rough counterpart in Mesosaurus.

Fig. 5. Vertebrae of Dictybolos tener n. g. and sp. A, cervical, UR 1054;
B, anterior dorsal, lateral (UR 1046); C, anterior dorsal, dorsal (UR 1046); D, mid-
dorsal, lateral (UR 1045); E, mid-dorsal, dorsal (UR 1045); F, partial presacral
from lumbar region (UR 1052); G, sacral, UR 1059; H, caudal, about 10th,
UR 1060. All approx. X 2.0.

385

v-

386 FIELDIANA: GEOLOGY, VOLUME 18

3. Vertebrae and Ribs: The vertebrae are strongly ossified and
characterized by widely spaced, broad, nearly horizontal zygapophy-
ses. The neural arches, however, are relatively narrow and neural
spines are moderately high. The zygapophyses are somewhat remi-
niscent of those of captorhinomorphs, but the arches are not of the
characteristic swollen type. The closest resemblances are to the ver-
tebrae of Araeoscelis. The principal features of the vertebrae are
shown in Figure 5 in which a series along the column is shown. The
ordering is based on vertebral features, and not upon details avail-
able from an articulated column. Some of the vertebrae of the holo-
type are in articulation but, except for a series of caudals, the details
are poor enough that they do not serve as a basis for ordering.

The transverse processes vary somewhat along the column. On
the most anterior vertebrae they are quite ventral, essentially arising
from the centra. More posteriorly they pass laterally from the arch
and the dorsal and ventral portions are essentially fused to form a
a single process. In the lumbar region this singularity tends to
weaken and the facets for the dorsal and ventral heads of the ribs
become more distinct. They are both clearly shown in the sacral
vertebrae. Caudal vertebrae are high and narrow. The first several
have very strongly recurved ribs with two partially distinct heads.

The centra are deeply amphicoelous and strongly ossified. They
are slightly keeled. Many of them show a pitting and vascular struc-
ture much like that which is seen in the skull bones. Centra and
arches are strongly fused and show no sutures.

A characteristic feature of the surfaces of the zygapophyses of
many of the vertebrae is a pattern of "gi'owth" rings, much like those
seen on specimens of Diadectes. Some of the larger specimens carry
as many as six concentric bands.

Ribs appear to have been present on all presacral vertebrae and
on the sacrals and several anterior caudals (fig. 6). Except for the
most anterior and posterior ribs of the presacral column, the heads
are essentially holocephalous. The neck of the ribs is narrow, but
beyond it the shaft is somewhat swollen, more or less like the ribs of
Mesosaurus. Just how this feature is distributed along the column
is not clear. Mid-dorsal ribs are quite swollen and this is also true
of the anterior caudal ribs. Cervical ribs show less of the character
and a few ribs, of uncertain position, which appear to belong to this
reptile, do not show marked swelling. The bone of the swollen ribs,
in cross-section, is thick and appears to be quite dense. Histological

OLSON: PERMIAN VERTEBRATES

387

D

Fig. 6. Representative ribs, A-E and coracoid F, of Dictybolos tener n. g.
and sp. A, cervical, UR 1127; B, anterior dorsal, UR 1138; C, mid-dorsal, UR
1139; D, posterior presacral, UR 1121; E, anterior caudal, UR 1116; F, coracoid,
UR 1130. All X approx. 1.0.

studies are being made, along with those of the teeth and jaws, and
will be treated specifically in a later paper.

4. Forelimb and Shoulder Girdle: The elements of the pectoral
appendage are illustrated in Figures 6 and 7. The scapula and cora-
coid are not coossified in any preserved specimen, and have not been
found together. The scapula is very distinctive, being short, broad
and somewhat recurved. The illustrated specimen is the best pre-
served but there are several in the collections. The coracoid was a
thin, plate-like element. In no specimens are the margins well pre-
served, and the bone appears to have been only partially formed in
the cartilage.

The humerus (fig. 8) is a long, slender element with both ends
capped by cartilage. Although some 15 identifiable humeri have been
found, all are somewhat crushed and none shows the original shape
well. The figure is based on a crushed specimen and the breadth is
somewhat increased over the life condition. Both the ectepidondylar
and entepicondylar foramina are present.

The radius and ulna are much as shown in Figure 8, although
there may be some slight distortion due to crushing. The radius

388

FIELDIANA: GEOLOGY, VOLUME 18

1^

Fig. 7. Postcranial elements of Dictijbolos tener n. g. and sp. A, scapula,
inner view, UR 1111; B, ilium, outer view, based on several specimens, especially
UR 1112; C, ilium, inner view, UR 1112; D, damaged pubis, UR 1053. A-C, X
2.0; D, X 1.7.

appears to have been a very strong element and somewhat twisted.
In contrast the ulna, of which there are very few recognizable speci-
mens, was very slender and light. Both had strong cartilaginous caps
on the proximal and distal ends. No carpals are known and it is pre-
sumed that they were unossified. Various long foot elements are
present and presumably some of these are metacarpals, but they can-
not be differentiated from the metatarsals and no positioning in the
foot is possible. Many phalangeal elements are present, but their
placement is out of the question. Some of the kinds are shown in
the Figure 8.

5. Pelvis and Hind Limb: The ilium, pubis and ischium were not
coossified and have only been found as separate elements. The ilium
is well shown in Figure 7. It has a fairly strongly developed caudal
process. The inner surface of the process and neck show a system of

OLSON: PERMIAN VERTEBRATES

389

complex gi'ooves and rugosities that mark the area of what pi'obably
was a quite firm Hgamentous attachment to the sacral rib(s). The
acetabulum was shallow, but well formed and with a strong dorsal
buttress. The pubis and ischium were not well ossified and appear
to have been rather broad and plate-like. There are no particularly
distinctive features preserved.

The femur (fig. 8B) is a long, slender, but robust bone which, like
the humerus, was capped by cartilage proximally and distally. The
shape of the distal end is well shown in some uncrushed specimens,
but the proximal shape is less clear. Trochanters appear to have
been weakly developed. The tibia and fibula are lightly built and
small relative to the femur. All of their features are subdued. The
information on the hind foot is the same as that for the forefoot, for
differentiation of elements of the two has not been possible.

Relafio7iships. — Dictybolos tener is distinctly different in morphol-
ogy from all of the well known Early Permian vertebrates of the
mid-continent region of North America. These consist mostly of

o

0

c

D

Fig. 8. Limb elements of Diciybolon tener n. g. and sp. A, humerus (right),
ventral and dorsal respectively, UR 1049 and 1105; B, femur (left), dorsal and
distal, UR 1135, 1136, 1137; C, phalangeal elements of various specimens; D, ra-
dius (left), UR 1061; E, ulna (left), UR 1129; F, tibia (right), from several speci-
mens, all fragmentary; G, fibula (right), UR 1117 and other specimens. A and B,
X 0.5, and others, from various sized individuals, scaled to match.

v-

390 FIELDIANA: GEOLOGY, VOLUME 18

captorhinomorphs and pelycosaurs and the new genus does not con-
form in any of its major features with members of these two groups.
Its unique features, related it would seem to its ways of life, tend to
overshadow some of the less specialized features which provide clues
to its relationships.

The long, slender limbs, with their weak trochanters, placed far
distally, suggest possible relationships to Araeoscelis, but these could
merely reflect special locomotor adaptations. The vertebrae show
closer resemblances to those of Araeoscelis than to those of any other
contemporary reptile. In both, the zygapophyses are broad and
rather flat, somewhat captorhinomorph-like, but the neural arches
are narrow. In the cervical region the transverse processes lie essen-
tially on the centrum in both. The ribs of Araeoscelis are, however,
dichocepahlous throughout the column whereas those of Dictybolos
are holocephalous except in the anterior and posterior parts of the
presacral column.

The evidence of the skull must be somewhat suspect in view of
the fact that it was reconstructed from individual elements. It has
many unique features, but the position of the temporal fenestra as
determined in the reconstruction is comparable to that of Araeoscelis.

The alternatives are to assign this genus to one of the established
groups or to use it as the basis for a new group. The latter would be
of very dubious use, and there is at least some basis for relating it to
the Araeosceloidea. This gi^oup as conceived by Romer (1966) in-
cludes some members of the earlier Protorosauria and like the earlier
group is open to some question. Araeoscelis, Kadaliosaurus, Trilopho-
saurus and Toxolophosaurus do have features that suggest they may
form a natural assemblage and it is with these members of the Arae-
osceloidea that the closest affinities of Dictybolos seem to be.

Habits.- — Many features of Dictybolos indicate that it was a fish-
eating reptile which was partially aquatic. The skull appears to have
been highly kinetic with junctions between elements formed by over-
laps of bone rather than sutures. The consistent loss of the more pos-
terior elements from the dentary suggests a very loose attachment
between the elements of the lower jaw. The sharp rows of marginal
teeth, with the slight ventral flexure of the anterior part of the den-
tary tooth row, fit well a general pattern of an active predator. While
they are not by any means definitive of fish eating, they could cer-
tainly have functioned in this way. The pterygoid was closely ar-
ticulated to the rest of the skull, but it is not beyond the general

OLSON: PERMIAN VERTEBRATES 391

range of form or tooth patterns found among vai'ious other Permian
reptiles. It does not suggest any particular type of diet. The skull
characters, especially the kinetic features, plus the dentition can be
interpreted as being adapted to the catching and swallowing of fairly
large, complete prey.

The position of the external naris is striking and strongly sug-
gestive of aquatic life, being set far back from the termination of the
snout. The postcranium is distinctive in the form of the limbs, but
the most impelling argument for possible aquatic life is the very low
level of ossification. The ends of all limb bones, apparently the
carpus and tarsus, and the junctions of the elements of the girdle are
all cartilaginous. This can, of course, be interpreted as the result of
immaturity, but the preponderance of creatures of a fairly standard,
large size suggests that they were adults, in contrast to the much
less well ossified elements from smaller, and presumably younger,
individuals.

Vertebrae, while distinctive, do not in themselves give much evi-
dence on the ways of life. Centra show considerable pitting, but
they are firmly joined to the arches and terminal ossification is well
formed. The ribs, however, have distinctly swollen shafts, as is char-
acteristic of many aquatic creatures. The late Paleozoic Mesosaurus
is a striking example of a more or less contemporaneous case.

Putting all these features together, it would appear that Dicty-
bolos is most reasonably interpreted as a semi-aquatic, fish-eating
reptile. It has not progressed as far in this direction as had Meso-
saurus and Stereostenmm. It shows an early tendency toward this
sort of habit in the araeoscelidoids, and one not matched otherwise in
the Early Permian of North America.

Associated Organisms

The assemblages: The beds that contain Dictyholos tener also carry
scrappy remains of various other animals. In bed number 16 of the
section, a few feet below bed 18, both vertebrates and plants occur.
The plants consist of large, partially compressed trunks of trees and
layers of excellently preserved leaves, fronds and seeds. A collection
has been given to L. R. Wilson of the Oklahoma Geological Survey
for study. Detailed identifications have not been made, but the flora
is clearly that of the usual lowland Early Permian type.

The assemblage in bed 16 and that in beds 18 and 19 represent
quite different types of deposition. Bed 16 consists of a grey to yel-

392 FIELDIANA: GEOLOGY, VOLUME 18

low and red shale, with occasional sandstone lenses. The shales have
the highly leached appearance which is characteristic of swamp de-
posits from this time and contain selenite crystals. There can be
little question that they represent swamp deposits formed close to
the margin of fresh water lakes. The higher beds, 18, 19 and 21 were
deposited in shallow waters, probably close to the shoreline of a lake,
but definitely to the lakeward side. They consist of shales, followed
by sandstone, and then with a gap filled by black shale, of the bone-
bearing dolomite. Only in bed 16 are plants and vertebrates asso-
ciated. Beds 18, 19 and 21 lack plants but contain the new reptile
Didyholos, v/hich has not been found in bed 16.

Direct associations in beds 18 and 19: The animals listed below
have been found in these beds in direct association with Dictybolos
tener.

Invertebrata
Conchostraca
Esther ia sp.

Vertebrata

Chondrichthyes
Xenacanthus sp, (teeth)
"Ctenacanthus" (spine)

Osteichthyes
Dipnoi
Gathorhiza serrata Cope (toothplate)
Actinopterygii

Platysomus cf. P. palmaris Cope (partial fish, scales)
Sphaerolepis arctata (Cope) (tooth plates)

Amphibia

Trimerorhachis, cf. T. insignis Cope (fragments of skull, jaws,
limbs and teeth)

Indeterminate remains of small amphibian

Reptilia

Ophiacodon sp. (small part of jaw, teeth)
Dimetrodon sp. (teeth)

Conchostracans are present in some phases of bed 19, mainly in
parts made up of rather thinly laminated, gray to brown sandstone.

OLSON: PERMIAN VERTEBRATES 393

They tend not to be present in the parts of this layer in w liich the
bones occur, although they are veiy widely scattered through the red
phases of the bed and in a few instances are found in the clusters
of bones.

Vertebrate remains, except for those of Dictyholos and Platyso-
mus, are very fragmentary and widely scattered. Some teeth and
bones occur in the red sandstones of bed 19, but most of them are in
the sandy shale lenses at the top of bed 18. Except for Platysomus,
the remains are badly broken and often worn. They appear to have
been transported and washed back and forth in the shore currents.

Scales of Platysomus occur in both beds 18 and 19 and are found
in direct association with bones of Dictyholos. Partially complete fish,
however, occur in sandy shale lenses of bed 18, with only occasional
scraps of reptile bones in association. This fish is a possible food
source of Dictyholos, although there is no direct evidence that it
served in this way. Tooth plates, listed as Sphaerolepis areata in
Olson (1967), are a common associate of Platysomus and occur rather
widely in both beds 18 and 19. It seems quite possible that these
actually represent tooth plates of Platysomus.

The shark teeth, Xenacanthus, are all very small and are widely
scattered through beds 18 and 19. One specimen of Gnathorhiza ser-
rata has been found, in bed 18. Together with "CtenacantJms" and
Trimerorhachis the forms listed above make up a typical aquatic as-
semblage. Added to them are Dimetrodo7i and Ophiacadon repre-
sented, except for a small fragment of jaw of Ophiacodon, only by
teeth. These clearly appear to have been transported. Dictyholos
is much the most common element and fits the environment under
the interpretation that it is a partially aquatic reptile.

The "sivamp" assemhlage: The animals from the deposits of bed 16
are as follows:

Chondrichthyes
Xenacanthus sp.

Osteichthyes

Paleoniscoids (small, genus undetermined)

Amphibia

Trimerorhachis cf. T. insignis Cope
Eryops cf. E. megacephalus Cope
Diplocaulus cf. D. magnicornis Cope

V-

394 FIELDIANA: GEOLOGY, VOLUME 18

Reptilia

Ophiacodon uniformis (Cope)
Dimetrodon cf. D. limhatus (Cope)

The composition of this assemblage is httle different from that of
beds 18 and 19. It lacks Platysomus and includes a small palaeonis-
coid and Diplocaulus magnicornis. The presence of the small pale-
oniscoid may well be just a matter of preservation, for the delicate
structures are likely to have been destroyed in beds 18 and 19. The
presence of Eryops and Diplocaulus magyiicornis may be of some sig-
nificance, for these two creatures are normally associated with pond
and swamp living assemblages. The co-ordinate lack of Platysomus
and Didyholos may be of some significance, if there was a food rela-
tionship as suggested above.

From what has been observed, it may be concluded that the ab-
sence of Didyholos in the swamp beds and presence in 18, 19 and 21
represents an ecological relationship. This, while quite possibly cor-
rect, must be viewed with some caution, for in a sandstone very sim-
ilar to that of bed 19, the beds at the McCann quarry (Olson, 1967)
from which many vertebrates have been obtained, Platysomus and
conchostracans are abundant, but no sign of Didyholos has been
found. Also, well preserved remains of Diplocaulus magnicornis,
Dimetrodon and Lahidosaurus oklahomaensis have come from these
sands, although not directly associated with Platysomus and the con-
chostracans. It seems evident that the environments of deposition of
the McCann Sandstone and bed 19 at Perry site 6 were similar. Thus,
although Didyholos is not known from swamp deposits, the absence
loses some of its weight as an indication of the life environment.

AN ASSEMBLAGE OF SMALL VERTEBRATES FROM

THE HENNESSEY FORMATION

EARLY PERMIAN OF OKLAHOMA

General Considerations

History of the Collecting Site

The site from which the vertebrates described and discussed in
this paper have come is located a short distance southeast of the
campus of the University of Oklahoma, Norman, Oklahoma (Sec. 13,
T. 8 N., R. 2 W.) in Cleveland County. It is on the property of
Mr. Amos Moses of Norman, Oklahoma, to whom I wish to express
my thanks for the opportunity to make the collection. The site was

OLSON: PERMIAN VERTEBRATES 395

brought to my attention about 20 years ago by the late Professor
J. Wilhs Stovall of the University of Oklahoma. A few years later
we collected a few specimens, including fi-agments of Lysorophus,
a skull of Captorhinikos, and some captorhinid vertebrae. The skull,
FMNH UR 183, was later (Seltin, 1959) referred to Labidosaurikos
meachami Stovall, and subsequently (Olson and Barghusen, 1962)
following Vaughn (1958), to Captorhinikos chozaensis Olson.

The existence of Lysorophus at this site has been casually men-
tioned in the literature, most recently in a faunal list from this site
(Olson, 1967).

No additional field work was undertaken until 1965. For some
time the site was "lost" as a result of the death of Professor Stovall,
changes in the area, and a faulty record of its position in the Museum
files. Weathering had almost completely obliterated surface indica-
tions of the vertebrate remains. After "rediscovery" in 1965, the hill
containing the fossils was excavated, a process not completed at the
time of writing. The collection described here has been obtained
through these quarrying operations.

Intensive collecting of the Hennessey Formation near Norman by
Stovall and his associates yielded a large collection of the pelycosaur
Cotylorhyyichus romeri Stovall (Stovall, 1937; Price and Romer, 1940;
Stovall, Price and Romer, 1966; Olson, 1967, 1968). The specimens
are all from about the same horizon as the quarry site. In addition,
Captorhinikos chozaensis has been found in the Hennessey at several
places in the Norman area. Except for the site under discussion in
this paper, the Hennessey Formation proper has not yielded other
vertebrates. One specimen of Cotylorhynchus romeri, the holotype,
came from about 40 miles to the north (Olson, 1968). Labidosaurikos
meachami (Stovall, 1950) has been described as being from the Hen-
nessey, but as pointed out elsewhere (Olson, 1967) this genus occurs
in transition beds between the Hennessey and underlying Garber
formation, along with Dimetrodon and Diplocaulus.

The Quarry: Distribution of Sediments and Fossils

The bone-bearing sediments that have produced the vertebrates
discussed below are between 5 and 6 feet in thickness. The quarry
was opened upon the nose of a hill and cut back into the hill to form
a north-facing exposure about 30 feet long (PI. V). About 20 feet to
the southeast of the quarry, across a small gully, continuation of the
bone-bearing bed was found, but elsewhere, to either side, no fossils

l-

396 FIELDIANA: GEOLOGY, VOLUME 18

are present, although sediments at the level of the producing layers
are exposed. The maximum extent of the fossiliferous shales across
the outcrops is about 50 feet.

To date the excavation has covered an area of about 350 square
feet and approximately 1,500 cubic feet of sediment have been exam-
ined for fossils. Although the specimens are somewhat clumped in
occurrence, it can be estimated fairly that they average about three
per cubic foot. Thus the total number of specimens in the materials
studied ranges in the neighborhood of 4,500. Of these, of course,
only a small part, several hundred, has been collected. Much of the
material is very fragmentary and with a few exceptions only articu-
lated specimens, skulls, jaws and well preserved single bones were
kept. Over one-half of all specimens found pertain to Lysorophus,
usually consisting of vertebrae and ribs. In general, remains of this
amphibian were collected only when preservation was exceptionally
good, much of an individual was present, or skulls were found, either
alone or associated with skeletons.

Vertebrates are scattered somewhat irregularly through the de-
posits, with rich and poor zones seeming to have little regular lateral
or vertical distribution. The sediments show modest variation
through the producing zone, but this as well has no definable pattern.
Bones tend to be more abundant and better preserved in some vari-
eties of sediments than others, but the differences are slight and
difficult to document.

The position of the quarry in bed number 5 of the general section,
first given in Olson (1967), is shown in Table 4. It lies in the upper
part of a thick bed of red shale. Not far above the upper level of the
bone producing layer are coarser sandy shales. These, of course, bear
no relationship to the deposition of the sediments of the quarry. The
sediment of the quarry basically is a red-shale. Structureless red
clay-shale makes up at least 80 per cent of the total. Irregularly
disposed patches of lighter colored, somewhat sandier shale occur
and in places small patches of pebbles, 1 to 5 mm. in diameter, are
present. The most distinctive sediment is a greenish-brown, brec-
ciated, slightly sandy shale. It shows no regular disposition either
vertically or horizontally.

Vertebrates occur in all the shale variants in the 5 to 6 foot fossil-
iferous zone. Concentration is least in the breccia. The only clear
regularity in the deposits is found in the vertical distribution of the
kinds of fossils. At the base is a zone, about 1 foot thick that carries
almost exclusively specimens of large individuals of Lysorophus. This

OLSON: PERMIAN VERTEBRATES 397

Table 4. — Measured Section of Hennessey Formation,
(from Olson, 1967)

Thickness
Bed Description (feet)

14 Coarse clastic, base of green fissile shale. Remainder coarse

brown sandstone 3.0

13 Uniform red shale 2.0

12 Hard green sandstone, increasing in thickness northward 0.5

11 Red shale with local lenses of sandy shale 29 .0

10 Sandy siltstone and shale, ranges in thickness from 6 inches to

6 feet (see beds 8 and 9 = beds 8, 9 and 10) 6.0

9 Red shale, passing laterally into sandy siltstone (=bed 10) 3.0

8 Hard green sandstone, pinching out laterally, but elsewhere pass-
ing under red shale (bed 9) to merge with bed 10 1.5

7 Uniform red shale 7.0

6 Red and green thin-bedded, fissile sandy shale 5.5

5 Red shale, sandy in places, bone in 5-foot interval, beginning 5

feet above the base 18.0

4 Red and green, fissile sandy shale 0.5

3 Red shale, base not exposed 5.0

2 Covered interval, some red shale in patches near top 58.0

1 Sandstone, top of brown sandstone near top of Garber-Hennessey

transition zone 2.0-|-

animal always occurs in compressed masses of vertebrae and ribs,
3 to 5 inches across and 8 to 10 inches deep. As far as can be deter-
mined each specimen consists of one individual. It appears that this
represents preservation of an estivating phase. After death the ani-
mals collapsed. This, along with subsequent compaction of the shale,
has produced an intricate mass of intertwined vertebrae and ribs,
with limb elements and skulls sometimes discernible. The top of
this layer is marked by a bedding plane.

Overlying the basal zone are 3 to 4 feet of sediment through which
are scattered remains of all of the types of vertebrates found in the
quarr5^ Lysoropkus is abundant, over 50 per cent of the total, some-
times in estivation position, and sometimes uncoiled. The remainder
is accounted for by individual bones, partial skeletons, skulls, jaws
and occasional teeth of lungfish. scales of palaeoniscoids, small am-
phibians and reptiles. Many specimens have been badly damaged
by compaction of the shale. Some small concentrations of bone con-
tain jumbled, sharply broken or cut elements of two or three species.
These may well be the product of regurgitation. Coprolites, with
mascerated bone, are fairly abundant.

Above this zone, ranging from a few inches to about I}-} feet in
thickness, is a zone rich in scrappy, macerated bones of larger ani-
mals. From this have come a few large teeth of carnivorous reptiles,

398 FIELDIANA: GEOLOGY, VOLUME 18

badly broken skulls, and partial skeletons of Captorhinikos chozaensis,
and teeth and partial skulls of Gnathorhiza serrafa. Much of the
material is so badly broken that it is undeterminable.

At the time of wilting, the quarry has not been exhausted. The
general fossil content is well known and probably very little new will
be found. Some of the genera represented in the present collections,
however, are known from but one or a few specimens. Additional
materials of these will be important if they can be found in subse-
quent work. What is described below, however, gives an adequate
representation of the overall content of this site.

CLASS OSTEICHTHYES
Subclass Sarcopterygia

Order Dipnoi
Family Lepidosirenidae

Gnathorhiza serrata (Cope)

Holotype. — Lower tooth, AMNH 7258, from the Permian of
Texas. Cope, 1883.

Referred specimens. — All from Hennessey Formation about 70 feet
above the base. Lower Permian, SW ^i, NW 3.1 sec. 13, T. 8 N.,
R. 2 W., Cleveland County, Oklahoma. FMNH UF 981, small up-
per tooth; UF 1024, upper tooth attached to "pterygoid" plate and
various scattered skull bones; UF 1023, lower tooth, jaw, cross crests
of upper tooth in place relative to lower, part of second lower tooth
and fragments of skull bones.

Discussion. — Although once a "rare" genus of lungfish, Gnatho-
rhiza has been found in abundance in recent years. Treatment of
the genus by Berman (1968) and Carlson (1968) has summarized
its history and earlier it was considered by Olson (1951) and by
Romer and Smith (1934). Much is now known of the skull morphol-
ogy and a wide range of teeth has given a good idea of the extent of
variation. It now seems clear that the common Lower Permian
species is G. serrata, with G. dikeloda less abundant and absent from
the Arroyo Formation and its equivalents, being present only in the
Vale and Choza.

G. serrata is abundant in the Wellington Formation of the north-
ern Permian exposures in Oklahoma, being known from the Orlando
site and from Perry sites 1, 2, 4, 5 and 6 (Olson, 1967). It occurs as
well in the Garber Formation at Pond Creek. Specimens have been

OLSON: PERMIAN VERTEBRATES

399

found in the Vale Formation of Texas, in Knox County (Olson, 1951)
and in Taylor County (Meade, 1968). Arroyo finds have long been
known and Berman (1968) has i-epoi'ted Gnathoriza serrata from the
Leuders Formation. It appears that Gnathorhiza is the lungfish re-
sponsible for the many lungfish estivation burrows that are known
from the Upper Pennsylvanian and Lower Permian, and finds of
specimens from many areas are now being reported, probably mostly
representing G. serrata.

The specimens referred to G. serrata in this paper are the first
known from the Hennessey Formation of Oklahoma and extend the
vertical range of this species into the upper part of the Lower Per-
mian. D. dikeloda has been found in the Choza, a Hennessey equiva-
lent, in Texas, but G. serrata has not been reported. No trace of
G. dikeloda has been found in the Oklahoma Lower Permian beds.

Reference of the new specimens to G. serrata is based upon strong
morphological resemblances and specifically upon the I'atio of the
anterior and posterior moeity of the lower tooth of UF 1023, Table 5.
It was noted earlier (Olson, 1951) that the known ratio in G. serrata
ranged from 1.3 to 1.5, whereas in G. dikeloda it ranged from 2.2 to
2.4. Additional materials have generally confirmed this marked dif-
ference as strongly exceeding variation of the ratio. UF 1023 has
a ratio of 1.4. Measurements upon which this is based as well as
those of the other referred specimens are given in Table 5.

The three referred specimens and fragments of others that have
been observed during collecting have all come from the upper part
of the producing beds. The two specimens with skull plates associ-
ated with teeth were from the uppermost bed in association with
fragmentary specimens of Captorhinikos chozaensis. This bed carries
scraps of large bones and appears to have been deposited under cir-
cumstances different from those that pertained during deposition of

Table 5. — Measurements of the specimens referred to Gnathorhiza
serrata in mm. Taken as in Olson (1951).

Specimen
number

FMNH UF 981
(upper)

FMNH UF 1024
(upper)

FMNH UF 1023

(lower)

Total
length

7.2

11.2
10.0

Length of

Posterior

Moiety

4.9

Length of

Anterior
Moiety

7.3

1^

400 FIELDIANA: GEOLOGY, VOLUME 18

the earlier beds which contain most of the fossils. The lungfish
clearly were not preserved from the estivation phase and they are
not known from the lowest producing level where Lysorophus occurs
in abundance in estivation burrows. No lungfish burrows have been
encountered as yet in the Hennessey Formation, although presum-
ably Gnathorhiza maintained the same habits as earlier.

SUBCLASS LABYRINTHODONTIA

Order Temnospondyli

Suborder Rhachitomi

Family Dissorophidae

Genus Tersomius

Tersomius mosesi^ new species

Holotype. —FMNB. UR 1214. Skull and jaws and postcranial
scrap. Skull badly crushed but nearly complete.

Horizon and locality. — Hennessey Formation, about 70 feet above
the base, Eaily Pei-mian, SW H, NW H, sec. 13, T. 8 N., R. 2 W.,
Cleveland County, Oklahoma

Referred specimens. — All from same horizon and locality as the
holotype. FMNH UR 1216, part of lower jaw and skull fragments;
UR 1218, front part of skull and lower jaws; UR 1219, skull and
lower jaws, ventral side exposed; UR 1220, jaws and part of skull
plus 3 or 4 vertebrate and other elements; UR 1221, lower jaw and
skull fragments; UR 1222, lower jaw; UR 1223, maxilla with well
preserved dentition; UR 1224, snout and lower jaw; UR 1225, jaw
and skull fragments; UR 1226, lower jaw; UR 1227, partial lower
jaw; UR 1228, partial lower jaw; UR 1229, partial lower jaw; UR
1251a, partial skull; UR 1285, lower jaw and limb elements (assoc?)
(see pi. VIE) ; UR 1286, lower jaw.

Diagnosis. — A small species of Tersomius with skull length, meas-
ured from the tip of the snout to the level of the end of the quadra-
tojugal, about 25 mm. (see fig. 9). Dermal bones lightly sculptured.
Dentary and maxilla-premaxilla with about 30 to 35 teeth, teeth long,
slender and slightly recurved. Suspensorium but a short distance
back of occipital condyles. Palatal tusks developed posterior to and
neai^ the anterior borders of the choanae, with an additional tusk on
the vomer somewhat lateral to the midline. Vertebrae with very
large hypocentra and strong pleurocentra (PI. VIA).

1 The species is named for Mr. Amos Moses of Norman, Oklahoma, upon
whose property the fossils described from the Hennessey Formation were collected.

OLSON: PERMIAN VERTEBRATES

401

D

Fig. 9. Tersomius mosesi n. sp. A, skull in dorsal view; B, skull in palatal
view; C, lower jaw in lateral view; D, back end of skull showing condition of otic
notch. All composite, based on various specimens, including the holotype. All
X approx. 2.0.

Description and relationships.- — Although there are many speci-
mens of T. mosesi in the collections almost all are poorly preserved
so that the description, illustrations (see fig. 9) and diagnosis must
be based on information from a number of individuals.

In his study of early dissorophid amphibians CaiToll (1964) gave
a thorough description of the skull and jaws of Tersomius and con-
cluded that there was but a single species, T. texensis, among the
kno\Mi materials. The specimens on which the new species is based
conform in most respects to his generic diagnosis, which is the same
as the species diagnosis. The presence of a light sculpturing on
T. mosesi does not agree with the diagnosis which cites a lack of
sculpturing, but some of the specimens of T. texensis do. in fact, show
faint patterns on the deiTnal bones.

The diagnosis also cited the number of marginal teeth as 45 to 50.
a number significantly larger than that in T. mosesi. This must,
however, be considered as a species character, which assumes signifi-
cance now that the genus is no longer monospecific.

That the specimens of T. niosesi are correctly assigned generically
may, of course, be open to some question, since the skulls and jaws
have relatively few unequivocal characters for separation of primitive

402 FIELDIANA: GEOLOGY, VOLUME 18

dissorophids. Clearly the specimens belong among the primitive dis-
sorophids. The otic notch is open, the skull is flat, with very delicate
ornamentation, and lacking the specializations found in the various
more advanced genera. Lack of armour may be a primitive feature,
as Carroll has indicated. In Teromius texensis the interpretation of
absence was based merely upon the fact that no armour plate was
found in association with the specimens. Almost no vertebrae are
known, however, so that the absence of armour plate, while sug-
gestive, is far from conclusive that none existed. T. mosesi also has
no associated armour plate and, as far as can be told, there was no
capping armour on the few preserved vertebrae. Once again, how-
ever, it is not certain that no plates were present.

The probable presence of the second vomerine tusk, lateral to the
midline, is another feature that suggests relationship with Tersomius.
The problem is complicated by the fact that the indications of this
tusk are not completely trustworthy on the one specimen, UR 1224,
on which it seems to exist, and also, of course, by the possibility that
this may occur in other genera of dissorophids. On the whole, how-
ever, it seems advisable to assign the new materials to Tersomius
rather than to adopt the alternative of erecting a new genus for which
no clear justification can be found.

Occurrence. — Altogether over 100 individuals of T. mosesi have
been seen in the deposits and about 75 have been identified in the
collections now in hand. Many of these are unprepared and have not
been formally referred, pending detailed study. All occur in the
middle layer of the quarry sediments, and none has been definitely
identified either in the lowermost bed, which contains largely Lyso-
sophus, or in the uppermost, characterized by highly fragmented
larger specimens.

The skulls and jaws of this little animal are extremely fragile,
more so than the skulls of Captorhinikos, Lysorophus or Goniorhyn-
chus, its more common associates in the site. All tend to be badly
crushed and broken and some quite clearly appear to be regurgitated
remains, often associated with fragments of other animals in a com-
mon mass of bone fragments. Occasionally skulls and jaws are asso-
ciated with postcranial materials that can be assigned to the species,
but single jaws are not uncommon. All parts of skulls that have been
found have jaws in association, but in many instances only a part of
the skull is preserved, as if it had been cut away from the rest by the
bite of some small carnivore.

OLSON: PERMIAN VERTEBRATES 403

The very sharp, recurved teeth iiKhcate a carnivorous habit for
this species, but its food must have been very small animals, perhaps
largely small, active invertebrates. What little information there is
on the limbs and vertebrae suggests that T. mosesi would have been
fully capable of locomotion on land. The deposits, however, as noted
in other descriptions, probably were formed under aquatic circum-
stances, but very near to land. Thus this little amphibian may have
lived on adjacent land, and been washed in or carried in l)y predators
or may, of course, have been a swimmer. That many of the remains
suggest predator action and the fact that very little articulated ma-
terial is found suggests that the remains were brought into the area
of deposition rather than that the animals actually lived in the de-
positing water.

SUBCLASS LEPOSPONDYLI
Order Microsauria
Family Gymnarthridae

Goniorhynchus new genus

Diagnosis. — A moderately small gymnarthrid amphibian with a
single row of lateral teeth in the skull and lower jaw. Six premaxil-
lary and 18 to 20 maxillary teeth above. One row of slender teeth
on margin of pterygoid and second row, with 3 or 4 teeth, on palatine
just posterior to internal naris. All teeth long, slender and sharp.
In marginal rows, longest teeth anterior with regular decrease in
length posteriorly along the tooth row.

External nares large and terminal. Overhanging rostrum. Pari-
etal with small pineal foramen, postparietals large, postorbital broad
with extensive contact with posterior margin of orbit. Supraoccip-
ital a broad, relatively short element. Dorsal surface of skull not
pitted. Measurements in Table 6.

Table 6. — Measurements in mm. of skulls of Goniorhynchus stovaUi

n. g. and sp.

Sk,

lOw

O]

Mx^

FMNH UR 1039 12.8
UR 1040 14.0

6.1
6.1

3.7
3.6

11.2
12.0

sbreviations:

i<^w, interorbital width

Mx^, maximum width of skull

Oi, orbital length

Sk], skull length along midline

1^

404 FIELDIANA: GEOLOGY, VOLUME 18

Goniorhynchus stovallii i^ew species

Ho/of?/pe.— FMNH UR 1039. Skull and lower jaws.
Horizon ayid locality.- — Hennessey Formation, about 70 feet above
the base, SW h, NW 14, sec. 13, T. 8 N.. R. 2 W., Cleveland County
Oklahoma.

Referred specimens. — Horizon and locality as for holotype. FMNH
UR 1040, skull and jaws; UR 1242, part skull; UR 1243, lower jaws;
UR 1244, skull, jaw and vertebrae; UR 1245, part skull and verte-
brae; UR 1246, front part of lower jaw, scrap; UR 1247, part of
lower jaw; UR 1248, part skull and vertebrae; UR 1284, crushed
skull, vertebrae; UR 1341, front of skull and lower jaws.

Diagnosis. — As for genus.

Description. — Goniorhynchus stovalli is represented in the collec-
tions by the specimens listed above, and by others not as yet pre-
pared. It appears that considerable additional postcranial material
pertains to this genus and species but much additional preparation
will be necessary to establish associations. This original report,
hence, is based primarily upon features of the skull, jaw and dent-
tion. Vertebrae preserved with the skulls are typically gymnarthrid
in general structure, with spool-shaped centra and low arches. Both
of the best preserved skulls are somewhat depressed by crushing.
UR 1039 the holotype has been broadened somewhat in the process
whereas UR 1040 has been somewhat elongated. The shape of the
skull in the figures has been based upon the holotype and is thus prob-
ably somewhat broader in proportion to length than was true dur-
ing life.

The dorsal and palatal patterns ai-e shown in Figure 10 A and B,
and the dorsal in Plate VI D. The pattern of the dorsal surface of
the skull can be seen to be typically gymnarthrid, fairly close to that
of Cardiocephalus, Pariotichus and Euryodus. Minor differences in
the shapes, proportions and relationships of the elements occur. The
most evident differences are found in the dentitions. The teeth of
Goniorhynchus are long and slender, with no formation of a bulbous
waist on the crowns. The six premaxillary teeth are the longest and
the maxillary teeth decrease regularly in length posteriorly. The
same relationships hold for the teeth of the dentary. Only one row
occurs above and there are no coronoid teeth on the lower jaw.

1 The generic name refers to the angled snout of the animal and the specific
name is in recognition of the late J. Willis Stovall.

OLSON: PERMIAN VERTEBRATES

40

4U0

PM

AMG

Fig. 10. Skull and lower jaws of Goniorhynchus stovalli n. g. and sp. A, dorsal; B, pal-
atal; C, oblique view of left side of posterior of skull to show stapes; D, occipital surface in
posterior view; E, cross-section through skull at level of anterior margin of the orbits, based
on UR 1341. A, B, and E, X 4.0; C and D, X 6.0.

The shapes and arrangements of the teeth thus differ notably
from those of any of the three genera noted in the last paragraph.
They are more like those described in Ostodolepis (see Romer, 1950).
On the basis of the skull elements and skull shape, there seems little
question that affinities are closer to the Cardiocephalus-Pariotichus-
Euryodus assemblage than to Ostodolepis, and the resemblance of the
dentition to the last mentioned is probably a matter of convergence.

The occipit of Goniorhynchus is illustrated in Figure lOD. It is
gymnarthrid in general structure. The exoccipital carries a very
large, centrally located foramen, undoubtedly for the hypoglossal
nerve. An exoccipital of Cardiocephalus cf. sternbergi desci'ibed by
Gregory, Peabody and Price (1956) shows a similar lai'ge foramen,
plus a smaller one, somewhat ventro-anteriorly, both presumed to
be for the exit of the hypoglossal nerve. The supi'aoccipital is pres-

406 FIELDIANA: GEOLOGY, VOLUME 18

ent and rather small. The occipital condyle is a slightly saddle-
shaped structure, characteristic of this group of gymnarthrids.

The stapes is well preserved in UR 1040, as illustrated in Fig-
ure IOC and Plate VIC. It consists of a short, rounded shaft, with
a stout process rising above it to the opisthotic in the general position
of a dorsal process. No enlarged foot-plate is present. As preserved,
the stapes does not rest medially against the periotic complex and a
fenestra ovalis has not been identified. It may be that crushing has
separated the foot from the periotic or it may be that a foot-plate
was present and not ossified. Laterally, the rounded shaft passes
into a more slender ventral extension, which is directed toward the
quadrate. The latter has a medially directed process to which, it
would appear, the stapes attached. Once again, however, there is no
contact in the specimen and either lack of ossification or crushing
may be the reason. In this instance, it appears that separation due
to crushing is the more probable explanation. Rising above this
lateral part of the stapes is a large, accessory element. Its base is
closely appressed to the stapes but does not appear to be fused to it.

The stapes appears to be very different from that described in
Cardiocephalus by Gregory, Peabody and Price (1956), but rather
like that of Pantylus (Olson, 1966, on data supplied by Robert Car-
roll). The functions of the stapes and its relationships to those of
other small amphibians are uncertain. What is required is a full
study of the detail from all specimens available before any generali-
zations can be safely made. Robert Carroll (1963, 1966, 1967) has
been gathering data for such a study and has made important con-
tributions to understanding of the microsaurs. This work is building
upon earlier studies by Gregory, Peabody and Price (1956) and by
Romer (1950). In addition, studies by Brough and Brough (1967)
have added important details to understanding of what they call the
"type microsaur" Microbrachis. Collation, as planned by Carroll,
should do much to clarify the morphology and relationships of these
creatures.

Most of the features of the basicranium and palate can be seen
in Figure lOB, D and E. No evidence of openings for internal carotid
arteries, as described in Cardiocephalus, have been found. Posteri-
orly, lateral to the basicranium, appears a very deep incisure. This
probably represents the place that structures from the jugular fora-
men, nerves IX, X and XI, and possibly a jugular vein emerged. A
large sphenethmoid is present. This canies a foramen rather well
forward from the basipterygoid articulation. It does not appear to

OLSON: PERMIAN VERTEBRATES 407

be the foramen noted by Gregory, Peabody and Pi'ice for the inter-
orbital vein, for it lies too far forward. Interpretation requires a
more thorough knowledge of its position relative to internal features
of the brain case. The shape of the anterior part of the spheneth-
moid is shown in Figure lOE, based on the broken surface exposed
at the posterior end of UR 1341.

Discussion. — The new specimens, referred to Goniorhynchus sto-
valli add considerably to known details of the structure of gymnar-
thrids. Only by a full study of these specimens in compai'ison with
other available materials will the full benefit of their excellent state
of preservation be realized. The purpose of this paper is to name the
new genus and species, to indicate its probable affinities, and to de-
scribe its essential features. The study being undertaken by Carroll
is well underway and the materials have been made available for his
work in which they will be considered in broad context.

The Hennessey specimens occur later in the Pennian than any
other clearly defined members of the Gymnarthridae. Prior to their
discovery the most recent were from the Arroyo FoiTnation of Texas,
appreciably earlier than the Hennessey, which appears to be equiva-
lent to the Choza. Cymatorhiza kittsi Olson and Barghusen des-
scribed earlier (Olson and Barghusen, 1962) was tentatively assigned
to the gymnarthrids on the basis of the peculiarly Euryodus-like
structure of the base of the teeth. This specimen is from a tongue of
the Chickasha Formation in the middle Flowerpot Formation of the
El Reno group and is considerably younger than Goniorhynchus. The
assignment, however, must remain tentative since no additional ma-
terials for further study have been found. No traces of gymnarthrids
have been found with the very well preserved specimens from the
Omega quarry (Olson, 1965) of about the same age as the beds from
which Cymatorhiza came.

Family Lysorophidae

Lysorophus tricarinatus Cope

Holotype. -FMNE. UC 6526. Partial vertebral centrum. Mid-
dle McLeansboro FoiTnation, early Conemaugh, Horseshoe Bend of
Vermillion River, Vermillion County, Illinois (Cope, 1877, p. 187).

Referred specimens. — All from Hennessey Formation, Early Per-
mian, SW H> NW M, sec. 13. T. 8 N., R. 2 W. Cleveland County,
Oklahoma. FMNH UR 1034, skull and jaws; UR 1036. part skull;
UR 1037, part skull and part skeleton; UR 1230, skull and jaws;

v-

408 FIELDIANA: GEOLOGY, VOLUME 18

UR 1231, part skull; UR 1232, vertebrae, ribs; UR 1233, part skull;
UR 1240, skull and jaws; UR 1288, skull and jaws; UR 1289, part
skull, vertebrae; UR 1290, skull and part skeleton; UR 1291, part
skull and vertebrae; UR 1292, skull and jaws, scrap; UR 1293, skull
and jaws, vertebrae; UR 1294, part skull and part skeleton; UR 1295,
part skeleton.

Systematics. — As described earlier (Olson, 1956), the systematics
of Lysorophus pose some difficult problems partly because of the
fragmentary nature of the holotype and refeiTed specimens from the
type locality and partly because much of the known material consists
of vertebrae that are very constant in morphology. Comparisons
with the holotype, of course, can involve only vertebrae and the limi-
tations of the holotype and the few referred specimens from the same
site do not allow any estimate of the extent of individual variation.
As far as vertebrae are concerned, no detectable differences occur
between members of any of the samples, which range from the Cone-
maugh of Pennsylvanian age to near the top of the Lower Permian.

Collections of Lysorophus from the Arroyo Formation contain a
substantial number of skulls and jaws as well as vertebrae. In the
absence of comparative materials other than vertebrae in the holo-
type, however, there has been little choice but to assign these mate-
rials to the type species, Lysorophus tricarinatus Cope. Much the
same applied when Lysorophus from the Vale and Choza, consisting
very largely of vertebrae and ribs, was described. It was unknown
whether or not adequate skulls and jaws would show differences were
they available.

Now about a dozen skulls and jaws, along with hundreds of speci-
mens of vertebrae and ribs, have been obtained from the Hennessey
Formation. The vertebrae and ribs, as is to be expected, show no
differences from those from other localities. Detailed analyses of
both the gross and small characters of the skulls and jaws from the
Arroyo samples and the new one from the Hennessey also fail to re-
veal any differences whatsoever in the morphology. Gross propor-
tions, proportions of the individual elements, the nature of the
sutures, positions of sense organs, jaw structure, hyoidean structure
and dentitions all are indistinguishable. As far as morphology is
concerned, all of the Clear Fork materials must be assigned to the
same species and there is no basis for separation of this species from
L. tricarinatus of the Pennsylvanian.

Occurrence. — Specimens of Lysorophus make up at least 50 per
cent of the individuals from the Hennessey quarry site. They occur

OLSON: PERMIAN VERTEBKATP^S 409

at all levels in the producing section and in association with all of the
other elements. The distribution, however, is not uniform.

The lowest bed from which vertebrates have come is a slightly
sandy clay-shale about 1 foot thick and marked off from the overlying
beds by a well-defined bedding plane. This lowest level contains,
almost exclusively, specimens of large individuals of Lijsorophus, each
preserved as a closely packed, intricately coiled mass of bone. Each
such accumulation appears to represent a single individual. In some,
skull elements and limb bones are found, but frequently maceration
is such that they are hard to extricate from the mass. It is assumed
that these specimens were preserved in crude burrows during an
estivating phase of their existence. All are of similar size, based on
measurements of the length of mid-column vertebral centra. They
vary from about 7 to 10 mm. in this dimension.

The matrix in the immediate vicinity of these specimens is firmly
cemented and varies from very light red through green, in contrast
to the deep red of the bed as a whole. On a cleaned surface of the
bed the specimens can be seen to be irregularly spaced, but not
clumped, and averaging about five to the square yard. There seems
to be little question but that these represent somewhat irregularly,
much compressed, cocoon-like burrows of this animal.

Throughout the remainder of the producing beds Lysorophus shows
no such regularity in the spacing, size of individuals, or form of pres-
ervation. Coiled specimens of various sizes are present. Uncoiled,
articulated skulls and vertebral columns are fairly common, and there
are large numbers of individual vertebrae and ribs, short segments of
column, and occasional skulls and jaws. Sizes in the free specimens
range from those with vertebral centra less than 1 mm. in length to
some larger than those from the basal bed. In the uppermost beds,
in which there are scrappy materials of larger animals, Lysorophus is
rare and very fragmentary. Like the other materials at this level,
specimens appear to have been washed in.

The middle beds, with their mixture of kinds of preservation,
seem to include specimens preserved from the free-swimming stages,
but the estivation "nodules" also are present. It would appear that
there had been considerable i-eworking at this level and perhaps
that the materials had been to some extent transported. The ex-
tremely delicate animals that are well preserved, including the small
specimens of Lysorophus, however, argue strongly against anything
but the most gentle actions on either count.

410 FIELDIANA: GEOLOGY, VOLUME 18

Suborder Nectridea
Family Keraterpetontidae

Peronedoni new genus

Diagnosis. — A small keraterpetonid nectridean, with known skull
lengths along dorsal midline ranging from 7.6 to 14.0 mm. The
skull is longer than wide, orbits elongated, "horns" short and jaw
articulation far forward of occipital condyles. But a single element
posterior to the orbit- — either postfrontal or postorbital. Interptery-
goidal vacuities large. Marginal teeth long, slender and sharp, con-
fined to premaxilla, anterior part of maxilla and anterior part of the
dentary. Palatal teeth restricted to three or four medial to internal
narial opening. Metacarpal and phlangeal elements relatively long,
narrow and well ossified. Vertebral centrum lacking scroll-like sculp-
turing such as found on Diploceraspis, Diplocaulus and Crossotelos
among the nectrideans.

Peronedon primus new species

Holotype.-'FMNll UR 1234. Skull, jaws, ten vertebrae includ-
ing atlas, ribs, part of shoulder girdle and part of right and left
forelimbs.

Horizon and locality. — Hennessey Formation, about 70 feet above
base, Clear Fork group. Early Permian. Southeast of Norman, Okla-
homa, SW M, NW I4, sec. 13, T. 8 N., R. 2 W., Cleveland County,
Oklahoma.

Diagnosis. — As for genus.

Referred specimens. — FMNH UR 1235, parts of two small indi-
viduals on single block of matrix; includes partial skulls and lower
jaws, badly damaged, two series of vertebrae and associated ribs;
UR 1236, large individual, about twice the size of the others, consist-
ing of a crushed skull and two vertebrae; UR 1237, part skull and
lower jaw, small; UR 1238, skull.

Description and discussion.- — In addition to the holotype and the
referred specimens other fragments pertaining to this genus and spe-
cies, recognized mainly from the sculpture pattern on the bone, are
present in the collections. All are within the size range of the referred
specimens and most closely approach the size of the smaller speci-
mens. The very small size has made preparation and study of the
specimens difficult, but excellent preservation, especially of the holo-

1 The name is given as an indication of the long, slender nature of the marginal
teeth, meaning pin-tooth.

OLSON: PERMIAN VERTEBRATES 411

type UR 1234, has made it possible to determine many significant
structural features. The morphology is shown in Figure 11, in which
a reconstruction of a small, immature specimen of Diplocaulus, is
shown for comparison. Before consideration of the details of form,
it will be helpful to assess the meaning of the small size.

Size.- — All of the specimens known are extremely small as com-
pared to adults of Diplocaulus, the only known contempoi'ary nec-
tridean. The very high degree of ossification of the endoci'anium,
the vertebrae and the carpal, metacarpal and phalanges seem to
argue that the individuals are mature. The skull lengths of UR 1234
and UR 1236 differ in length, 7.6 mm. and 14.0 mm., respectively.
The magnitude suggests that growth rather than interspecies varia-
tion of adults is involved. It is in the smaller specimen that ossifica-
tion of the limb bones occurs, but only in the larger are the endocranial
bones visible. Although it appears probable that these specimens do
represent a very small species, it cannot be determined definitely that
they are not actually juveniles of the species.

Very small skulls of Diplocaulus magnicornis which can be related
to large adults through a series of intermediate stages show ossifica-
tions of the dermal surface of the skulls and of the vertebrae com-
parable to those of Peronedon. That this also involves endocranial
bones and limb bones is not known, although it may be the case.
Also, another lepospondylous amphibian, the microsaurian Lijsoro-
phus, has a high level of ossification even in very small individuals.
It is possible that this is a common feature within this order. Thus,
with this additional evidence, reservation upon the adult condition
of the specimens on the basis of the degree of ossification must be
maintained.

No large individuals are known, but the only specimens of the
genus come from one site in which, with the exception of fragmentary
materials from the uppermost part of the producing beds, small in-
dividuals make up about 98 per cent of the total collection.

The following discussion, for the most part, treats the individuals
as if they give a fair representation of the adult conditions, but this
may be in error. If this is the case, then descriptions of both the
morphology and habits apply only to the juveniles and the compari-
sons made with adults of other genera and species are open to some
question.

Skull and Jaws.— Pertinent features are shown in Figure 11 A
and B, and measurements are given in Table 7. The outline of the
skull has been based upon the holotype UR 1234, and the recon-

412 FIELDIANA: GEOLOGY, VOLUME 18

Table 7. — Measurements in mm. of specimens of Peronedon primus

n. g. and sp.

Sk, Sk,^ lO^ Lj, H^ V, Vh

FMNH UR 125 (type) 7.6 10.4 0.9 4.6 7.8

UR1236 14.0 4.2 1.8

UR1237 8.8

Abbreviations:

H^, maximum width at tips of horns

lO^, interorbital width

LJi, maximum length cf lower jaw

Skj, skull length along midline

^hm, maximum skull length, to tip of horns from snout

Vh, maximum height of vertebra

Vi, central length of vertebra along base

struction of the palate has been made upon this outline, but with the
information from UR 1236 and 1237. Figure HE shows the skull of a
small, juvenile specimen of Diplocaulus inagyiicornis. The pattern of
the dermal bones and the shape are somewhat different from those of
Peronedon, but the general features are similar. The most striking
differences lie in the absence of a bone in the position of the post-
orbital (excluded from the orbit) in Peronedon. The large parietal is
well preserved and this absence appears to be real, not a matter of
preservation. The pattern shown in the immature Diplocaulus mag-
nicornis is that found in all members of the genus. Also, no evidence
of the lacrimal has been found in Peronedon. This may express the
actual condition, but the bone may be so small, with the skull less
than 8 mm. long, that detection is not possible. Other minor differ-
ences in dermal patterns probably are of no great significance.

The most strikingly distinctive feature of Peronedon among the
keraterpetontids, and especially in comparison to Diplocaulus and
Diploceraspis (Beerbower, 1963) is the shape of the marginal teeth.
These, as shown in Figure IIC, are very long, slender and sharp.
This is in marked contrast to the short, blunt teeth of the contem-
porary Diplocaulus or the earlier Diploceraspis. This type of tooth
formation is not found in the juveniles of Diplocaulus in which the
teeth, as far as known, resemble those of adults very closely.

The palatal reconstruction of Figure 11 B may have some inac-
curacies, for preservation of UR 1236 and 1237 is only fair. The
large interpterygoidal vacuities, the posterior position of the large
adductor fossa, the position and number of palatal teeth, and the
internal nares are quite certain. The position and size of the opis-

PM

PRF

c

Fig. 11. Peronedon primus n. g. and sp. A, dorsal view of skull. Based on various speci-
lens with outline from holotype UR 1234, relative to which the scale is X 7.5; B, palatal view
f skull. Based on various specimens with outline from holotype UR 1234, relative to which
le scale is X 7.5; C, lateral view of skull, based on UR 1234, X 7.5; D, dorsal view of vertebra
•om UR 1236, X 5; E, outline of .skull and dermal elements of Diplocaulus ma gnicornis Cope
ased on juvenile animal with skull length about 17 mm. along mid-line.

413

^'

414 FIELDIANA: GEOLOGY, VOLUME 18

thotie is more questionable, since this is present only on the left side
of UR 1236 and not well preserved there.

Postcranium.^ — The vertebrae are typically nectridean, as shown
in Figure IID. The centrum is elongate and spool shaped, but lacks
the scroll-like sculpturing found in Diplocaulus and Diploceraspis
(Beerbower, 1963), and also in Crossotelos among the urocordylids.
The parapophysis and diapophysis are both present, arising from a
common base on the centrum, as in Diplocaulus and Diploceraspis.
The most striking feature of the postcranium is the forelimb, as seen
in UR 1234. The shoulder girdle was broad and flat, as in Diplo-
caulus, but no details are visible in the specimen. No humeri have
been certainly identified but the right and left radius and ulna are
present. They are so small, about 2 mm. in length, that details
are not well shown. In articulation with one pair are well ossified
carpal elements accompanied by partially articulated metacarpals
and proximal phalanges. The metacarpals are about one-half the
length of the radius and ulna and the proximal phalanages are but
slightly shorter. Thus the feet appear to have been very large in
comparison to the forelimb and to the body as a whole. This is, of
course, in very sharp contrast to the condition in Diplocaulus. With-
out a doubt these creatures could have walked about on land without
difficulty.

Relationships and habits. — The characteristics of the skulls, jaws
and postcranium given in the preceding paragraphs leave no doubt
that Peronedon is a fairly normal nectridean and that it is closely
associated taxonomically with Diplocaulus and Diploceraspis within
the Family Keraterpetontidae. The forward position of the jaw ar-
ticulation, the large interpterygoidal vacuities, and the large, poste-
riorly placed adductor fossa are important in this regard. In addition,
the sculpture pattern of the dermal surface of the skull and jaws is
typical of that found in Diplocaulus and Diploceraspis, a pattern that
is immediately recognizable even on very small fragments of bone.
The dentition, the pattern of the dermal bones, the lack of vertebral
sculpture on the centra, and the large forefeet set the genus distinctly
apart from these relatives.

Interpretation of the adaptations are based upon the proposition
that these specimens are adults or subadults, but it is possible, as
noted, that they are juveniles. Dentitions suggest that the teeth are
used for selective feeding, rather than for more or less indiscriminate
gathering of food from the bottom of ponds or for mud-grubbing.

OLSON: PERMIAN VERTEBRATES 415

Very small invertebrates probably were a primary source of food.
Whether Perouedon fed on land or in the water is uncertain, although
feeding on land would be a distinct possibility in view of the arrange-
ment of the teeth and jaws. Feeding habits almost certainly were
different from those in Diplocaulus. In D. magnicornis, for which
small juveniles are known, the dentition is known to be very sim-
ilar throughout the full growth series, so that the differences are not
merely juveniles versus adults, if the specimens of Peronedon are, in
fact, juvenile.

The ability to walk on land has been indicated in connection with
the large limbs and feet. That these animals did actually live on land
part or full time cannot be known. In the same deposits occur both
terrestrial and aquatic creatures. The orbits are directed dorsally,
much as in bottom living animals, but the position is little different
from that found among semi-terrestrial salamanders of the present
time. The adaptations in general appear to be very much like those
of the gymnarthrid Goniorhynchus from these same deposits.

CLASS REPTILIA

Subclass Anapsida

Order Captorhinimorpha

Family Captorhinidae

Captorhinikos Olson

Captorhinikos parvus new species

Holotype. —FMlsiR UR 1250. Skull and part of right lower jaw.

Horizon and locality. — Hennessey Formation, about 70 feet above
the base. SW U, NW M, sec. 13. T. 8 N., R. 2 W., Cleveland
County, Oklahoma.

Diagnosis. — A small species of Captorhinikos with skull length
ranging from about 23 to 26 mm. Skull broad, with maximum width
about two-thirds that of the skull length. Upper dentition with four
premaxillary teeth, 13 to 15 marginal maxillary teeth, and two inner
rows on maxillary, the outer with five and inner with three teeth re-
spectively. Premaxillary teeth long, but not recurved. Second and
third maxillary teeth robust and long.

Lower jaw with second and third teeth elongated. Fifth tooth
inset slightly and continuing as part of inner of two rows of teeth in
posterior part of tooth row. Labial row of four oi- five teeth begin-

Z--

416 FIELDIANA: GEOLOGY, VOLUME 18

ning back of level of fifth tooth. Coronoid process of lower jaw
strong, and post-coronoid ramus long and slender.

Referred specimens. — Horizon and locality as for holotype. FM-
NH UR 1251, part skull, jaws and skeleton; UR 1252, front end of
lower jaw; UR 1253, 7 vertebrae; UR 1254, crushed skull, jaws and
postcranium ; UR 1255, skull and jaws; UR 1256, skull and jaws;
UR 1257, skull and jaws; UR 1258, skull and jaws; UR 1259, part
skull and jaws; UR 1262, part skull; UR 1263 part skull, showing
maxillary teeth; UR 1264, part skull and jaws; UR 1265, part skull
and jaw; UR 1266, front end of skull; UR 1267, jaws, skull fragments;
UR 1268, part of skull and jaws; UR 1269, part skull and jaws; UR
1270, front of skull and jaws; UR 1271, part lower jaws; UR 1272,
lower jaw; UR 1273, lower jaw; UR 1274, part lower jaw; UR 1275,
lower jaw; UR 1276, part lower jaw; UR 1277, part lower jaws; UR
1278, lower jaw; UR 1279, parts of skull and jaw; UR 1280, lower
jaw; UR 1281, lower jaw; UR 1282, maxillae and dentaries; UR 1283,
part of lower jaw.

Descriptions. — The skull and lower jaws of Captorhinikos parvus
n. sp. are as shown in Figure 12 and Plate VII. The skull is covered
over its full outer surface with a fine, reticulate marking not shown
in the figures. The general shape of the skull and jaws and the dis-
position of the component elements are very much as in Captorhinus.
No supratemporal, however, has been identified and its presence is
uncertain.

The skull is quite broad in comparison to its width. The poste-
rior margin of the temporal region appears to exhibit a structure that
is unusual among captorhinids. This is shown well in the holotype,
as figured, but is not as clear in other specimens. It may have been
somewhat exaggerated by crushing in the holotype. The dorsal plat-
form of the skull ends in an abrupt, transverse line, as in most capto-
rhinomorphs, but this line, carried latero-ventrally passes somewhat
forward exposing the occipital flange of the squamosal laterally. The
squamosal surface carries back ventrally in a somewhat distinct proc-
ess covering the quadrate nearly to the end of its articular surface.
This is the only feature in which the skull surface shows even mod-
erate differences from other captorhinids.

The palate, illustrated in Figure 12C, is reconstructed from the
holotype and UR 1250 and UR 1255. It is a normal captorhinid
palate, but is distinct in lacking teeth on the pterygoid, palatines or
vomers and in being broad and rather flat. An ectopterygoid appears

OLSON: PERMIAN VERTEBRATES

417

A

STA QU

Fig. 12. Capforhinikos parvus n. sp. A, skull, dorsal aspect; B, skull and jaw,
lateral aspect; C, skull, palatal aspect; D, lower jaw, dorsal to show dentition;
E, lower jaw, lateral to show shape, see B for elements. Based on various speci-
mens. All approx. X 2.0.

to be present, but its definition is not completely clear. The inter-
pterygoidal vacuity is moderately open and the cultriform process of
the parasphenoid is long and slender.

The lower jaw is as shown in Figure 12D and E. It is rather long
and narrow and has a strong coronoid prominence. The post-coro-
oid ramus is long and slender and a small retroai'ticular process is
developed. There are no striking differences from jaws of other small
captorhinomorphs such as Captorhinus and small species of Labido-
saurus.

The dentition is the most distinctive feature of Captorkinikos par-
vus. Principal features are illustrated in Figures 12C, D, E and 13C
and F. In the upper jaw four incisor teeth and 14 or 15 marginal
maxillary teeth are visible laterally. The incisor teeth are rather
long but are not recurved as in Capiorhinus or Labidosaunis. All are

418 FIELDIANA: GEOLOGY, VOLUME 18

of about the same size. The fourth and fifth maxillary teeth are large
and the remainder gi'adually diminish in size posteriorly.

The maxilla extends lingually from this row of teeth and carries
two additional, longitudinal rows. The outer of these, immediately
adjacent to the most lateral tooth row, includes five teeth, and the
inner three. These numbers appear to be standard, for they are con-
stant in all specimens in which this area is preserved.

The second and third teeth in the lower jaw are long and robust.
Traced posteriorly they lead to a large fifth tooth which is somewhat
inset and to a series of three to five additional teeth along the inner
margin of the dentary. This forms the primary row of teeth of the
lower jaw\ Latero-posteriorly to the fifth tooth of this row, lies a
series of five or six teeth, that form an outer row. Viewed laterally
these seem to be continuous with the more anterior teeth, but when
the rows are viewed from above this proves not to be the case.

This dentition is unique among the known captorhinids, but is of
the general pattern found in Captorhinikos chozaensis, and unlike that
of Captorhinus, on the one hand, and Labidosaurikos, on the other
(fig. 13).

Many partial skeletons, small suites of associated elements and
individual bones of Captorhinikos parvus are in the collections. Those
listed in the referred specimens have been prepared, but much unlisted
and unprepared material also is in the collection. The most impor-
tant aspect of this material is that it consistently shows a high degree
of ossification of the long limb elements, indicating maturity of the
individuals. Particularly important in this regard is UR 1254 in
which well ossified postcranial elements are associated with a skull.

The postcranial materials fall closely within the habitus of small
captorhinids, and are extremely difficult to differentiate from those
of small specimens of Captorhinus. It may be that this would be pos-
sible by use of fairly large samples in which the extent of variation
was evident. As matters stand at present, however, no clear-cut
distinctions between the vertebrae and limb elements of Captorhini-
kos parvus and Captorhinus have been found.

Discussion.- — The genus Captorhinikos was first named from the
Vale and Choza Formations of Texas, with two species, C. valensis
Olson and C. chozaensis Olson (Olson, 1954). Both of these were
based on rather fragmentary materials. Vaughn (1958) identified as
C. chozaensis materials from the Hennessey Formation of Oklahoma.
Later, this was accepted by me (Olson and Barghusen, 1962), and
other specimens, one from the quarry site that has yielded C. parvus,

OLSON: PERMIAN VERTEBRATES

419

and two others from just north of Norman, Oklahoma, were used to
augment the descriptions. In the course of development of the quarry
over the last three years additional material of C. chozaensis has been

B

Fig. 13. Diagrams of positions of teeth. A, Captorhinikos chozaensis Olson,
maxillary and premaxillary; B, C. valensis Olson, maxillary and premaxillary;
C, C. parvus n. sp., maxillary and premaxillary; D, C. chozaensis Olson, dentary;
E, C. valensis Olson, dentary; F, C. parvus n. sp., dentary. Not to scale.

found. Most of it is very scrappy and comes from the uppermost
level as described on pages 420-421.

When the small individuals were first found, it was assumed that
they were immature individuals of this C. chozaensis. It has become
clear that this is not the case. The long limb elements are strongly
ossified, indicating their adult nature, and long bones of specimens
of immature C. chozaensis from the quarry are poorly ossified, even
though they are at least twice the length and width of the elements
of C. parvus. In addition, as the skulls and jaws were prepared, it
was found that the dental patterns differed markedly in the two spe-
cies (see Fig. 13). The dentition of C. parvus bears somewhat closer
resemblance to that of C. valensis than to C. chozaensis. It is known,
however, that with increase of age in Captorhinikos and in Lahido-
saurikos as well, the number of rows of teeth may increase. Thus on
the basis of dentition alone, in particular the lower dentition, it could
be argued that C. parvus represents a young stage of C. valensis, al-
though hardly of C. chozaensis. Somewhat greater reorganization
during growth would be necessary to derive the upper dentition of

l^

420 FIELDIANA: GEOLOGY, VOLUME 18

C. valensis from that of C parvus but this is not entirely impossible.
It is thus largely the indications of maturity of C parvus that show-
it to be a distinct species and not an immature growth stage of C.
valensis. It is probable that other differences would be found were
more complete specimens of C. valensis at hand, but to date none
has been found.

C. parvus is abundant in the quaiTy. Hundreds of individuals
have been recognized in the course of operations, and about 150 have
been collected. Most of those not taken consisted of extremely badly
preserved specimens, due mostly to very excessive crushing, individ-
ual bones, skull plates, fragments of jaws, and miscellaneous jumbles
of postcranial elements. The abundance of this delicate animal, the
well preserved skulls with the jaws in place, and the partially articu-
lated skeletons suggest that it lived at or near the site of deposition.
Undoubtedly processes of concentration acted to bring so many to-
gether, but the source area must have been nearby and limited. Only
Lysorophus, which is shown by its burrows to have lived in this place,
exceeds Captorhinikos parvus in abundance.

Captorhinikos chozaensis Olson

Holotype. ^FMNR UR 97, part skull and lower jaw. Choza For-
mation, Clear Fork Group, Early Permian, Loc. FA, Foard County,
Texas (Olson, 1954).

Referred specimens. — All from Hennessey Formation, early Per-
mian, Cleveland County, Oklahoma (see Olson and Barghusen, 1962).
FMNH UR 183, skull and jaws. SW U, NW I4, sec. 13, T. 8 N., R.
2 W.; UR 857, partial skull and skeleton, NE 1.,, NW U. sec. 29, T. 9
N., R. 2 W.; UR 858, partial skeleton, locality as above; UR 859, par-
tial skull and skeleton, locality as above; OUSM 4-1-53, part skull and
jaws, locality as for UR 183; USNM 21275, skull and partial skele-
ton, S y2, sec. 24, T. 8 N., R. 2 W. (Vaughn, 1958).

Discussion. — Earlier discussions (Vaughn, 1958; Olson and Bar-
ghusen, 1962) have considered the existence and distribution of C.
chozaensis in the Hennessey Formation. One of the specimens in-
volved in these discussions, UR 183, is from the Hennessey site under
consideration here. The specimen was collected a number of years
before the site was opened by quarrying, so that its precise level in
relationship to more recently obtained materials is not certain, al-
though clearly it was from somewhere within the 5 to 6 feet of beds
that have produced the rest of the collection.

OLSON: PERMIAN VERTEBRATES 421

Remains of C. chozaensis are scattered through all but the very
lowest producing bed of the quarry section. Remains are mostly
very fragmentary, consisting of scraps of skulls and jaws and occa-
sional vertebrae. These have not been given formal status in the
collections and have not been numbered. In the uppermost produc-
ing bed partial skeletons, associated with skulls and jaws, occur, but
they are very badly fragmented by post depositional movement of
the enclosing sediment. The most frequent association is with the
lung-fish Gnathorhiza, but scraps of other genera and much unidenti-
fiable bone occur at this level. It appears that all that is present has
been washed in, deposited in a very soft sediment and badly damaged
by compaction and lateral stretching of the matrix.

C. chozaensis is readily differentiated from the smaller species,
C. parvus, described in this report, by the very poor ossification of
smaller specimens, the smallest of which exceeds the adults of C.
parvus by about a ratio of 2:1. The limb elements have very poorlj'^
ossified ends in all but the largest specimens of C. chozaensis, where-
as the small limb bones of C. parvus, which I'uns up to about 10 mm.
in length, are fully ossified. Only if very excellent materials are pres-
ent for comparison can the two species be differentiated on the basis
of morphology, without regard to size. This is most readily done by
comparisons of the dentition (see fig. 13) . Whether or not there are
proportional differences in the skulls, jaws and postcranial structures
is difficult to determine because of the distortions to which both spe-
cies are subject.

Except in the uppermost level of the quany, C. chozaensis is much
less abundant than C. parvus. The absence of anything but frag-
ments in the middle beds, those in which C. parvus is abundant, sug-
gests that remains of C. chozaensis may have been carried in from
some distance, whereas the smaller species presumably lived close to
the site of deposition.

Other Remains

In addition to the materials described in the preceding pages,
many undescribed specimens are in the collections from the Hen-
nessey Quarry. Most of these are unprepared and are either tenta-
tively assignable to the genera and species already known or will be
assignable once they have been exposed. Some specimens, however,
do not pertain to the described species, but are at present not con-
sidered to be sufficient for designation of new taxons or for assignment
to established genera or species. In addition to identifiable remains.

V'

422 FIELDIANA: GEOLOGY, VOLUME 18

a large number of coprolites containing badly decomposed bone, com-
pletely unidentifiable, and small agglomerations of macerated but
undecomposed bones and teeth are present. The latter, which on
occasion do include identifiable specimens, appear to be concentra-
tions that have resulted from regurgitations of undigested hard frag-
ments. The bones often show evidence of breakage, which appears
to be due to biting and crushing, and the concentrations may contain
two or three species and frequently include small fish scales.

These additional remains add considerably to the knowledge of
the assemblage at this site and for that reason are summarized below,
even though treatment must be very tentative.

Palaeoniscoid fishes: Small scales that appear to pertain to palae-
oniscoid fishes are scattered throughout the deposits and occur in
small concentrations in the regurgitated bony pellets. The scales are
essentially rhombohedral, ganoid structures with the surfaces marked
by several parallel ridges oriented along the long axis of the scale.
They all seem to pertain to a single type of fish, but it has not been
possible to identify them beyond probable palaeoniscoid affinities.
The only other fish remains in the deposits are those of Gnathorhiza,
for no crossopterygians or xenacanth sharks, which might be part of
the fauna, have been found.

Lahyrinihodont amphibian: A single "large" central element of a
vertebra has been found. It is a crescentic piece, probably a hypo-
centrum, which measures about 15 to 17 mm. in greatest width. The
shape is very different from the hypocentra of Tersomius, appearing
more like that common to such labyrinthodonts as Trimerorhachis.
This specimen probably represents a labyrinthodont, but the possibil-
ity that it is a reptilian intercentrum cannot be completely excluded.
No such intercentra have been found associated with Captorhiyiikos.
In the sacral region of Cotylorhynchus, however, rather large inter-
centra occur between the centra proper, fused into the complex in
adults. It is possible that in juveniles these elements might be free
and that the intercentrum found in the Hennessey locality might
have come from this genus. This is improbable, but not impossible.

Pelycosaurs: Unless the intercentrum noted in the last paragraph
is pelycosaurian, the only remains that have been found of reptiles
of this group appear to be related to the sphenacodonts. One of the
odd aspects of the Hennessey Formation and its fauna (see Olson,
1967) is the absence of any carnivorous reptiles, in particular the
absence of Dimetrodon, which might be expected since it is present in
the equivalent Choza Formation of Texas and is also abundant in the

OLSON: PERMIAN VERTEBRATES 423

transitional beds from the Garbei- to the Hennessey, which He from
about 70 to 120 feet lower in the section.

A lower jaw, FMNH UR 1241, illustrated in Plate VIIE, appears
to be from a small, predaceous pelycosaur. The dentary is strongly
developed, with a prominent, anterior, chin-like symphysis and a
deep, flat dentary ramus that rises up to form a subdued coronoid
prominence. The teeth are somewhat curved, slender, sharp-pointed
cones, with the anterior teeth somewhat longer than the posterior.
The posterior part of the jaw is damaged so that the presence or ab-
sence of an angular flange has not been determined. This specimen
appears to be a very advanced sphenacodont reptile, and as such
may be of considerable significance. It occurs in deposits of the
Early Permian that almost immediately predate those of the Upper
Permian from which very primitive proto-therapsids are first known.
This specimen is sufficiently preserved to be definitive of a new genus
and species, but since work will continue in the quany, it is hoped
that more complete specimens will be found and that they can be
used for a more adequate description and diagnosis.

Another small specimen, FMNH 1243, is a maxilla with teeth
that are similar to those of the lower jaw of UR 1241. It is about
the same size and may possibly pertain to the same species. It does,
how^ever, have a fine sculpture pattern, rather like that found in some
specimens of Tersomius. No sculpturing is present on the outer sur-
face of the dentary of the lower jaw. Assignment thus is uncertain.
Also in the collections is a very poorly preserved small skull and lower
jaws in which the skull has a temporal fenestra low in the partly pre-
served tempoi'al area. The teeth seem to be rather different from
those of UR 1243, being blunted and more widely spaced and the
temporal fenestra lies rather more ventrally than might be expected
if the specimen were of a genus as advanced as UR 1243 appears to
be. This specimen, UR 1342, probably is a small pelycosaur, but its
affinities are very uncertain.

In addition to the small, presumably pelycosaurian specimens, a
few large teeth of carnivores have been found, UR 1343. These are
without much question the teeth of a large sphenacodont, perhaps
Dimetrodon (PI. VII). One was found in the middle zone of the quarry
and the others in the upper zone associated with scrappy fragments
of bone. They give the first evidence of a large, predaceous carnivore
in the Hennessey Formation.

v-

424 FIELDIANA: GEOLOGY, VOLUME 18

ABBREVIATIONS USED IN FIGURES

ANG, angular PF, postfrontal

BO, basioccipital PM, PMX, premaxilla

D, dentary PO, postorbital

ECT, ectopterygoid PRE, prefrontal

EXO, exoccipital PT, pterygoid

FR, frontal QJ, quadratojugal

IP, interparietal QU, quadrate

IT, intertemporal SA, SANG, surangular

JU, jugal SM, SMX, septomaxilla

JUF, jugular foramen SP, splenial

L, LA, lacrimal SPH, SPHETH, sphenethmoid

MX, maxilla SQ, squamosal

NA, nasal ST, supratemporal

NAR, naris STA, stapes

PA, parietal TA, tabular

PAL, palatine TF, TEMP FEN, temporal fenestra

PAS, parasphenoid VO, vomer

PER, periotic

ABBREVIATIONS USED IN DESIGNATION OF SPECIMENS

FMNH, Field Museum of Natural

History
KU, University of Kansas
OUSM, University of Oklahoma,

Stovall Museum

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Berman, D.

1968. Lungfish from the Lueders Formation (Lower Permian, Texas) and the
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835.

Brough, M. C. and J. Brough

1967. Studies on lower tetrapods. I. The lower Carboniferous microsaurs.
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1968. The skull morphology and estivation burrows of the Permian lungfish
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Carroll, R.

1963. A microsaur from the Pennsylvanian of Joggins, Nova Scotia. Nat.
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Case, E. C.

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Cope, E. D.

1878. On the Vertebrata of the bone bed in eastern Illinois. Proc. Amer. Philos.
Soc, 17, pp. 52-63.

Daly, Eleanor

1968. A new procolophonoid reptile from the Lower Permian of Oklahoma.
Jour. Paleo., 43, pp. 767-787.

Fox, R. and N. C. Bowmak

1966. Osteology and relationships of Captorhinus agiiti (Cope) (Reptilia: Cap-
torhinimorpha). Univ. Kansas Publ.: Vertebrata, Art. II, pp. 1-79.

Gregory, J. T., F. E. Peabody and L. I. Price

1956. Revision of the Gymnarthridae, American Permian microsaurs. Bull.
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1925. Ein neuer Pelycosaurier aus der unteren Permformation Sachsens. Geol.,
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1968. Permian vertebrates from South Taylor County, Texas. Master's Thesis.
University of Texas.

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2. A new captorhinomorph reptile; 3. Lungfish in the Vale; 4. The skull of

Gnaihorhiza dikeloda Olson; 5. An eryopid amphibian. Fieldiana: Geol., 10,

pp. 89-128.
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10, pp. 211-218.
1956. Fauna of the Vale and Choza: 11. Lysorophus, Vale and Choza; Diplo-

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426 FIELDIANA: GEOLOGY, VOLUME 18

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300 pp.

Plate I. Cricotillus brachydens Case.

A. Skull, lateral, K. U. 350.

B. Skull, dorsal, K. U. 350.

C. Lower jaw fragment, dorsal, holotype, K. U. 349.

D. Lower jaw fragment, ventral, holotype, K. U. 349.
All X L5.

427

V-

Plate II. Pleuristion brachycoelous Case.

A. Skull, lateral, UC 676, X 1.6.

B. Skeleton in nodule, OUSM 3-0-S19, X 1.2.

C. Skeleton in nodule, OUSM .3-0-S19, X 1.2.

D. Vertebrae of holotype, K. U. 351a, X 2.4.

E. Vertebrae and femur of referred specimen, K. U. 351b, X 1.25.

428

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Plate III. Bone concentrate in matrix from Wellington, Perry site 6, from which
isolated elements of Dictybolos tener n. g. and sp. have come. This
is typical of the concentrations that occur in the sandy shale lenses.

429

v-

Plate IV. Drawings of Dictybolos tener n. g. and sp. to show details of some
structures.

A. Pterygoid in ventral view, UR 1043.

B. Small part of dentary showing basal fluting of teeth, lateral.

C. Small part of dentary showing basal fluting of teeth, posterior.

D. Large tooth showing strong development of fluting and the broad
base in postero-lateral aspect, UR 1132.

E. Maxillary teeth showing distal fluting, UR 1157.
All much enlarged.

430

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D

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431

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Plate V. The quarry site in the Hennessey in the SWI4 NW^ sec. 13, T. 8 N.,
R. 2 W. Various stages in the excavation are shown.

432

Plate VI. A. Tersomius moae^i n. sp., part of lower jaw and vertebrae in ventral
view, UR 1220, X 2.

B. Tersomius mosesi n. sp., UR 1285, part of jaw and limb elements,
X2.

C. Goniorhynchus stovalli n. g. and sp., left side of back of skull
from ventro-postero-lateral, showing stapes and its relationships to
surrounding elements, UR 1040, X 5.0.

D. Skull of holotype of G. stovalli in dorsal view, UR 1039, X 3.0.

E. Snout of G. stovalli in dorsal aspect, UR 1341, X 3.0.

F. Snout of G. stovalli in ventral aspect, UR 1341, X 3.0.

433

Plate VII. A. Skull and part skeleton of Peronedon primus n. g. and sp.
UR 1234, X 4.

B. Skull of Captorhinikos parvus n. sp., lateral view of holotype
UR 1250, X 1.6.

C. Skull of Captorhinikos parvus n. sp., palatal view of holotype
UR 1250, X 2.0.

D. Teeth of carnivorous pelycosaurs, UR 1343, X 0.8.

E. Lower jaw of very small sphenacodont pelycosaur, UR 1241, X 4.

434

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