Postilla

Peabody Museum

of Natural History
Yale University

New Haven, CT 06511

Me
29G4K

—_—

JAN 19 anton

LIBRARIES |

(Received 27 April 1983)
Abstract

Two species of the middle Eocene palae-
anodont (Mammalia) genus Metacheiromys,
M. marshi Wortman, 1903 (=M. tatusia
Osborn, 1904) and M. dasypus Osborn, 1904
(=M. osborni Simpson, 1931), are recog-
nized as valid. The previously described
Palaeanodonta (Edentata) are reviewed and a
new subfamily, Propalaeanodontinae, is
erected for Propalaeanodon. Propalaeanodon
is the plesiomorphous sister-group of the
remaining metacheiromyids. The
Epocoicotherlidae is a paraphyletic family in-
cluding the monophyletic Epoicotherlinae
and a number of poorly known genera that
can not presently be assigned to distinct
subfamilies.

Key Words

Metacheiromys, Palaeanodonta, Edentata,
Propalaeanodontinae, indeterminate Pri-
mates, fossil mammals.

Introduction

The Palaeanodonta are an extinct, archaic
group of Paleocene to Oligocene, eden-
tatelike mammals of uncertain affinities

© Copyright 1984 by the Peabody Museum of Natural
History, Yale University. All rights reserved. No part of
this publication, except brief quotations for scholarly pur-
poses, may be reproduced without the written permis-
sion of the Director, Peabody Museum of Natural History.

Postilla. Number 192

27 March 1984

ew of the Palaeanodonta

Robert Milton Schoch

which, with one exception, are known solely
from the early Tertiary of the Rocky Moun-
tain region of the western United States. The
one possible exception is a palaeanodont
specimen reported from the Oligocene of
West Germany (Heissig, 1982).
Metacheiromys Wortman, 1903, was the
first genus of palaeanodonts to be de-
scribed; however, this genus has never been
photographically illustrated and has not been
critically reviewed since Simpson’s (1931)
classic study. In the past decade there has
been a resurgence of interest in the Palae-
anodonta and a number of new species have
been described (West, 1973; Rose, Bown
and Simons, 1977; Rose, 1978, 1979; Heissig,
1982; Rose and Emry, 1983). However,

no systematic review of the known genera
and species of palaeanodonts has been at-
tempted. Here | revise the species-level
taxonomy of Metacheiromys and illustrate
the genoholotype and the more important re-
ferred specimens housed in the Peabody
Museum of Natural History (including speci-
mens which have been newly discovered in
the Peabody Museum Collections). Finally, |
briefly review the known Palaeanodonta.

Abbreviations

Institutions

AMNH American Museum of Natural
History, New York City

YPM Vertebrate Paleontology Collec-

tions, Peabody Museum of
Natural History, Yale University,
New Haven

2 Metacheiromys and the Palaeanodonta

Postilla 192

YPM O Osteology Collections, Peabody
Museum of Natural History,
Yale University, New Haven

Statistics

CV Coefficient of Variation

M Mean

OR Observed range

SD Standard deviation

All measurements were taken with a Helios
dial caliper and are expressed in millimeters.

Systematic Paleontology

CLASS Mammalia Linnaeus, 1758, p. 14
SUBCLASS Theria Parker & Haswell, 1897,

p. 448

INFRACLASS Tribosphenida McKenna, 1975,

Os 25)

SUPERCOHORT Eutheria Gill, 1872, p. 1

COHORT Edentata Cuvier, 1798, p. 142

ORDER Palaeanodonta Matthew, 1918, p. 620

Discussion

The two families Metacheiromyidae
Wortman (1903, p. 347) and Epoicotheriidae
Simpson (1927, p. 285) have generally been
regarded as closely related and have been
placed together in Matthew's (1918) subor-
der Palaeanodonta (Colbert, 1942; Simpson,
1945, 1959; Rose, 1978, 1979; but fora
contrary view, see Emry, 1970). As Rose
(1978, p. 665) has recently noted, the
Palaeanodonta are recognizable by the fol-
lowing suite of characters:

1) Distinctive, large canines which show
normal occlusion; |.e., the lower canines
occlude in front of the upper canines
(Colbert, 1942).

2) The progressive reduction in size and
number of cheek teeth.

3) The progressive reduction and loss of
enamel on the cheek teeth.

4) Development of a posteriorly-placed
medial buttress on the mandible with an
internal mandibular groove beneath it.

5) A fossorially adapted skeleton.

Matthew (1918) originally proposed the

-alaeanodonta as a suborder of the order

Edentata, but also suggested that it might
show affinities with both the Pholidota (pan-
golins) and Xenarthra (Edentata). Subse-
quently, most authorities (e.g., Simpson,
1931, 1945; Colbert, 1942; Gazin, 1952)
placed the Palaeanodonta in the Edentata; ;
Simpson (1931) argued strongly against
pholidotean ties for the Palaeanodonta. In
1970, Emry described a new manid,
Patriomanis, and discussed the then known
palaeanodonts and pangolins. He concluded
that the manids were derived from the
metacheiromyids and thus placed the
palaeanodonts in the order Pholidota. How-
ever, Emry dropped the use of the term
Palaeanodonta ‘‘since the mutual affinities of
the three families are not clearly known”
(Emry, 1970, p. 507). Rose (1978, 1979) has
recently suggested, on the basis of new ma-
terial, that the Xenarthra, Pholidota and
Palaeanodonta together form a monophyletic
clade relative to other eutherians, but the re-
lationships within this trichotomy (i.e., which
two groups are more closely related to each
other relative to the third) is as yet unre-
solved. Szalay (1977) came to essentially the
Same conclusions on the basis of a recon-
sideration of the astragalocalcaneal complex
of these three groups. Here | adopt Szalay’s
(1977) higher level classification of the
Palaeanodonta and tentatively consider this
group to be a distinct order which is possibly
referable, along with the orders Xenarthra
Cope (1889, p. 657) and Pholidota Weber
(1904, p. 412), to the cohort Edentata Cuvier
(1798, p.' 142):

FAMILY Metacheiromyidae Wortman, 1903,
p. 347

SUBFAMILY Metacheiromyinae Wortman,
1903; Os 84:7

Metacheiromys Wortman, 1903, p. 347

Type Species

Metacheiromys marshi Wortman, 1903
(=M. tatusia Osborn, 1904).

3 Metacheiromys and the Palaeanodonta

Included Species

The type species and M. dasypus Osborn,
1904 (=M. osborni Simpson, 1931).

Distribution

Middle Eocene (Bridgerian) of the Bridger
Formation, Bridger Basin, Wyoming.

Revised Diagnosis

Metacheiromyines distinguished by the fol-
OnP lee

Ve he
canines large, compressed (with triangular
bases) and enamel-bearing; postcanines
small (vestigial), single-rooted; most of
length of jaw edentulous; shelf for lower
horny plate not grooved, narrower and less
conspicuous than in Palaeanodon; and os-
sified bullae complete.

lowing features: dental formula

Metacheiromys marshi Wortman, 1903,
p. 347

(Figs. 1—5; 7A, C; 8; 9)
Synonymy

Metacheiromys marshi Wortman, 1903,

p. 347, figs. 105—108 (non fig. 109)
Metacheiromys tatusia Osborn, 1904, p. 165
Metacheiromys marshi: Simpson, 1931,
psc0s, tigs: SA; 113A; 19

Metacheiromys tatusia: Simpson, 1931,

bE SOS: TIGS 1,386; |S3B—F, 15A, 18, 20, 21
(non fig. 22)

Metacheiromys tatusia: Emry, 1970, fig. 30C
Metacheiromys sp.: Szalay, 1977, fig. 12B

Lectotype

YPM 12903, left dentary with root of canine
and alveoli for first two postcanines (Fig.
1A—C). Lectotype selected from the original
type material by Simpson (1931, p. 304).

Postilla 192

Paralectotypes

YPM 12903 (the following specimens may
pertain to the same individual as that rep-
resented by the lectotype), right maxilla
fragment bearing a broken canine (Fig. 1E,
F): left upper canine (Fig. 1G, H); glenoid
cavity of right scapula (Fig. 1K—M); proximal
and distal ends of right humerus (Fig. 2);
proximal two-thirds of right ulna (Fig. 3A—C);
axis of second cervical vertebra which is
missing the odontoid process (Fig. 11, J);
skull fragments; vertebral fragments (mostly
cervical, thoracic and caudal centra); rib
fragments; and distal end of radius.

Original syntypes subsequently excluded
from the genus and referred to the order
Primates, genus indeterminate (Simpson,
1931, p. 304): YPM 12908, right acetabular
part of pelvis (Fig. 7B); proximal and distal
ends of right tibia (Fig. 6).

Horizon and Locality of YPM 12903

Middle Eocene, probably Bridger B at Grizzly
Buttes, Bridger Formation, Bridger Basin,
Wyoming.

Discussion of YPM 12903

As Osborn (1904) and Simpson (1931) noted,
all of the specimens catalogued under YPM
12903 were presumably collected together
(although the collector and date are un-
known, presumably collected by a Yale Sci-
entific Expedition in the early 1870s), but
represent parts of at least two individuals
without duplication of any parts. Thus, YPM
12903 includes parts of the skull, dentary,
forelimb and vertebral column of a
metacheiromyid and parts of the pelvis and
hindlimb of a primate.

Holotype of Metacheiromys tatusia
AMNH 11549, skull, right dentary and the

majority of the skeleton (described and illus-
trated by Simpson, 1931).

4 Metacheiromys and the Palaeanodonta

Horizon and Locality of AMNH 11549

Collected in 1903 by Albert Thomson from
middle Eocene-aged strata, Bridger Bo at
Grizzly Buttes, Bridger Formation, Bridger
Basin, Wyoming.

Specimens Referred to M. marshi in the
Peabody Museum

YPM 13500, proximal end of right humerus;
fragments of distal ends of right and left
humeri; proximal and distal ends of both
femora (Fig. 4B, C, G); proximal ends of both
tibiae; and miscellaneous vertebrae: col-
lected by J. W. Chew in 1873 from middle
Eocene-aged strata, probably Bridger C, at
Dry Creek, Bridger Formation, Bridger Basin,
Wyoming.

YPM 13501, fragments of pelvis, includ-
ing parts of right and left ischia (Fig. 9);
fragments of left femur; proximal and distal
ends of right and left tibiae (Fig. 5); proximal
half of right fibula (still in matrix); partial ar-
ticulated tarsus and metatarsus (Fig. 8A, B)
of right pes; miscellaneous phalanges and
sesamoids, including an ungual phalanx of
the ?manus (Fig. 8D—F); poorly-preserved
vertebral centra of the thoracic and lumbar
series; and first seven caudal vertebrae pre-
served articulated and partly embedded in
matrix (Fig. 9). According to Simpson (1931,
p. 305), YPM 13501 originally included the
last two sacrals. Traces of glue and a fresh
break are evident on the anterior surface of
the first preserved caudal of YPM 13501, but
the two sacrals mentioned by Simpson
(1931) have presumably been lost since he
described this specimen. YPM 13501 was
collected by the Yale Scientific Expedition of
1873 from middle Eocene-aged strata, prob-
ably Bridger B, but possibly Bridger C, at
Grizzly Buttes, Bridger Formation, Bridger
Basin, Wyoming.

YPM 13502, posterior left dentary frag-
ment with base of ascending ramus (Fig.
1D); miscellaneous vertebral centra including
an axis missing the odontoid process and a
number of caudals; glenoid cavity of right
scapula; proximal ends of both humeri; distal

Postilla 192

end of right humerus; a nearly complete sac- —
rum with partial left ilium and acetabular part
of pelvis (Fig. 8C); proximal end of right
femur; distal ends of right and left femora
(Fig. 4A, D, H); proximal ends of right and
left tibiae; distal end of right tibia; and mis-
cellaneous isolated foot bones, including an
ungual phalanx: collected by the Yale Scien-
tific Expedition of 1873 from middle
Eocene-aged strata, Bridger B at Grizzly
Buttes, Bridger Formation, Bridger Basin,
Wyoming.

YPM 13503, broken vertebral centra, in-
cluding axis of second cervical vertebra miss-
ing the odontoid process; proximal end of
right humerus; distal fragments of right and
left humeri; proximal end of right femur; dis-
tal end of left femur; proximal end of left
tibia; right ilium and acetabular part of pelvis
(Fig. 7A); proximal end of left ilium and
acetabular part of pelvis; and incomplete
sacrum (Fig. 7C): locality data the same as
for YPM 13502.

YPM 40066, proximal end of right femur;
distal end of right femur; proximal end of
right humerus: no locality data; this speci-
men bears YPM Accession number 1072
which indicates that it was in O. C. Marsh's
possession in 1877; presumably from the
Bridger Basin, Wyoming.

YPM 40067, miscellaneous vertebral
centra and rib fragments; glenoid cavities of
both scapulae; partial left humerus; part of
shaft of right humerus; left ulna (Fig. 3D, E);
proximal half of left radius (Fig. 4E, F); mis-
cellaneous foot bones and bone fragments:
collected by J. F. Page from middle
Eocene-aged (Bridgerian) strata of the
Bridger Formation in the area of Grizzly
Buttes, Bridger Basin, Wyoming, 6 Sep-
tember 1871.

Revised Diagnosis
Smallest known species of Metacheiromys;

two lower postcanines approximately Sub-
equal in size.

5 Metacheiromys and the Palaeanodonta

Metacheiromys dasypus Osborn, 1904,
p. 164
(Fig. 10)

Synonymy

Metacheiromys dasypus Osborn, 1904,

p. 164

Metacheiromys dasypus: Simpson, 1931,
p. 306, figs. 3C, 4—8, 10-12, 14, 15B, 15C,
iG ralh7,, 22

Metacheiromys osborni Simpson, 1931,

pm: S06; 11g. 3D

Metacheiromys dasypus: Emry, 1970, fig.
28C

Holotype

AMNH 11718, skull, jaws and partial skele-
ton.

Horizon and Locality of the Type

Collected by Walter Granger in 1903 from
middle Eocene-aged strata, Bridger Bp at
Grizzly Buttes, Bridger Formation, Bridger
Basin, Wyoming.

Holotype of Metacheiromys osborni

AMNH 12119, right dentary and anterior part
of left dentary.

Horizon and Locality of AMNH 12119

Collected by P. Miller in 1904 from middle
Eocene-aged strata, Bridger Dz at Lone Tree,
Bridger Formation, Bridger Basin, Wyoming.

Referred Specimens

YPM 40068, proximal end of left humerus;
proximal end of left femur; proximal end of
right tibia; partial right astragalus (Fig. 10A,
C); right cuboid (Fig. 10B, D); miscellaneous
phalanges, other foot bones and bone frag-
ments: collected by G. G. Lobdell from mid-
dle Eocene-aged (Bridgerian) strata, Bridger
Formation, in the Grizzly Buttes area, Bridger
Basin, Wyoming, 4 September 1871.

Postilla 192

YPM 40069 (YPM Accession number
511), head of right astragalus; two incom-
plete metatarsals; first phalanx of second
digit of left pes (Fig. 10E, F); first and second
phalanges of second digit of right pes: col-
lected by S. Smith and J. W. Chew on 17
September 1873 from middle Eocene-aged
Strata, probably Bridger B, Bridger Forma-
tion, Bridger Basin, Wyoming.

Revised Diagnosis

Largest known species of Metacheiromys,
approximately 75% larger than M. marshi;
second lower postcanine much smaller than
first.

Description of MVetacheiromys

The known morphology of Metacheiromys |s
adequately described in Wortman (1903) and
Simpson (1931). However, these works are
illustrated only by simple line drawings.
Therefore, | supplement Wortman’s and
Simpson's descriptions by photographically
illustrating the genoholotype and selected re-
ferred specimens of Metacheiromys (Figs.
1—10). Except for differences in absolute
size and relative size of the second lower
postcanines, the two species are identical in
known morphology.

Discussion of Metacheiromys

In 1903, as part of a study of the Eocene
mammals in the Marsh Collection of the Yale
Peabody Museum, Jacob L. Wortman de-
scribed a new genus and species of ‘‘pri-
mate,’’ Metacheiromys marshi, based upon
YPM 12903. Primate affinities for
Metacheiromys were based primarily on the
tibia (Fig. 6) which is distinctly primate in
morphology (see discussion by Wortman,
1903, p. 351). He allied his new taxon with
the extant aye-aye of Madagascar,
Daubentonia (=Cheiromys). Wortman was
under the impression that the materials
catalogued under YPM 12903 pertained to a

6 Metacheiromys and the Palaeanodonta

Postilla 192

ee eee eee eS SEE

single individual. However, as noted above,
YPM 12903 is a composite of at least two
individuals of approximately the same size
and without duplication of any elements:
parts of the head, forequarters and vertebral
column of a palaeanodont and parts of the
hindquarters of a primate. Thus, he was mis-
led as to the affinities of Wetacheiromys.
Also in 1903, an American Museum of
Natural History field party led by Walter
Granger discovered two partial ‘‘edentate™
skeletons in the Eocene Bridger Formation
of Wyoming, AMNH 11549 and AMNH
11718 (Simpson, 1931). Upon study, it was
quickly recognized that these skeletons per-
tained to Wortman’s genus, that
Metacheiromys was an ‘‘edentate”’ and that
YPM 12903 was a composite specimen.
Osborn (1904) published a brief (three un-
illustrated pages) announcement clarifying
the status of Metacheiromys marshi and
coined the names Metacheliromys tatusia
and M. dasypus for AMNH 11549 and
AMNH 11718 respectively. In 1918 Matthew
described in detail the closely related genus
Palaeaonodon and discussed the relation-
ships of the Metacheiromyidae. However, It
was left to Simpson (1931) to describe, illus-
trate and discuss the genus Metacheiromys.
Osborn (1904) distinguished M. dasypus
as being much larger than M. marshi, and M.
tatusia as being smaller than M. marshi. As
Simpson (1931) noted, M. dasypus Is con-
siderably larger (by about 75%) than M.
marshi/tatusia and is also distinguished by a
relative reduction in size of the second lower
cheek tooth. Simpson (1931) also noted that
the lectotype of M. marshi is only slightly
larger and heavier (more rugose) than the
holotype of M. tatusia. Indeed, Simpson
(1931, pp. 305-6) stated that “it is quite
possible that a large series of specimens
would show M. tatusia and M. marshi to in-
tergrade completely.’’ However, Simpson
(1931) retained these species as distinct.
Furthermore, Simpson described a fourth
species of Metacheiromys, M. osborni, on
the basis of a single dentary, AMNH 12119,
that is ‘’slightly longer than in M. dasypus
(about 10%), stouter, canine larger, bone

more swollen around alveolus” (Simpson,
1931, p. 306).

| believe that the specific distinctions be-
tween M. marshi and M. tatusia, and be-
tween M. dasypus and M. osborni are ex-
tremely dubious. Rose (1978) has suggested
that palaeanodonts may have been sexually
dimorphic, as is the extant edentate anteater
Myrmecophaga (Grasse, 1955). However,
even without the presence of pronounced
sexual dimorphism, the differences seen be-
tween the presumed species within each
pair (M. marshi/tatusia and M. dasypus/
osborni) are extremely slight and suggest
that they may be due to individual variation
(confounded in part by differing ontogenetic
ages of the individuals concerned). In anal-
ogy, within the single species of the extant
cingulate (Edentata), Dasypus novemcinctus
(the nine-banded armadillo), as represented
by osteological specimens in the Peabody
Museum of Natural History, | found as much
variation in size and robustness among indi-
viduals as is seen between M. marshi-M.
tatusia and M. dasypus-M. osborni (Tables 1
and 2). Furthermore, | have found Simpson's
(1931) allocations of small specimens of
Metacheiromys to either M. tatusia or M.
marshi to be unreplicable. YPM 13501, a
specimen which Simpson referred to the
smaller M. tatusia includes some limb bones
which, if anything, are slightly larger than
some which he referred to M. marshi.
Simpson referred only three specimens to
M. dasypus /osborni, two of which are the
holotypes. The third specimen, a few frag-
ments of a hind foot of Metacheiromys
(YPM 40069: Fig. 10E, F), shares no ele-
ments in common with the two type speci-
mens.

Taking all of the above considerations into
account, | recognize only two species of
Metacheiromys, M. marshi Wortman, 1903
(= the junior subjective synonym M. tatusia
Osborn, 1904) and M. dasypus Osborn, 1904
(= the junior subjective synonym M. osborni
Simpson, 1931).

With this synonymy in mind, the bio-
stratigraphic distribution of Metacheiromys
can be reviewed (cf. Simpson, 1931, p. 307).

eee eS EE ES EE EEE ESSE EE EEE Eee

7 Metacheiromys and the Palaeanodonta

Table 1

Metric data on Dasypus novemcinctus.

Postilla 192

YPM O Length upper cheek Length lower cheek
Number tooth row tooth row

Right Side Left Side Right Side Left Side
2888 23a) 2S 25.5 24.5
2334 25.1 25.0 26.2 26.0
2739 2397) D5) DOW. D3)
2740 26.5 26.4 28.1 Dil)
4474 26.1 25.8 26.4 Dies
9505 22.5 2228 22.6 22.9
10065 24.7 24.3 26.2 25:85
OR 22.5—26.5 22.8—26.4 22.6—28.1 22.9—27.3
M 24.61 24.50 25.46 2 WO
SD 1.42 1.30 1.93 1275
CV IY 5S VAS 6.32
Lowest observed
value as a % of
highest observed
value 84.9 86.4 80.4 83.9

Depth of mandible
between 4th & 5th
cheek teeth

Right Left
5.4 5.4
5.6 5.5
5.1 5.2
6.8 6.8
6.2 72
5.3 5.0
6.3 6.2
5.1-6.8 5.0-7.2
5.81 5.90
0.63 0.85
10.84 14.41
75.0 69.4

Table 2

Metric data on Metacheiromys.

Depth of dentary at

Length of lower cheek

mental foramen tooth row

M. marshi, type 6.1 3.8)
M. tatusia, type 5.0 3.8
Lower value as a %

of higher value 82.0 Sy!
M. dasypus, type 8.1 6.4
M. osborni, type Q.7/ 5.9
Lower value as a %

of higher value 83.5 O22

8 Metacheiromys and the Palaeanodonta

In the Bridger Basin, Wyoming, both M.
marshi and M. dasypus are known from as
low as the Bridger Bz (Matthew, 1909). The
highest known stratigraphic occurrence of
M. marshi is probably in the Bridger C,
whereas M. dasypus is known as high as the
Bridger Dz level.

A Review of the Known Palaeanodonta

In this section | review the published record
of palaeanodonts and briefly discuss the sa-
llent characters of each genus.

ORDER Palaeanodonta Matthew, 1918,
p. 620

FAMILY Metacheiromyidae Wortman, 1903,
p. 347

Included Genera

Propalaeanodon, Palaeanodon and
Metacheiromys.

Discussion

The Metacheiromyidae appear to be a dis-
tinct clade within the Palaeanodonta.
{Character-state polarities can be assessed
for palaeanodonts by making the reasonable
assumption that Amelotabes (see below) is
generally the most primitive known
palaeanodont (Rose, 1978).] Early in the
course of their evolution, the
metacheiromyids reduced the postcanine
teeth to small, cylindrical pegs, with blunt,
rounded crowns that lacked enamel, and
were separated by short diastemata. These
character-states were converged upon by
derived epoicotherlids. The metacheiromyids
retained the symplesiomorphy of a relatively
long dentary [which may have been covered
by a horny plate (derived)] and they are
united by the synapomorphous feature of
lacking occlusion between the postcanines
and thus they do not show occlusal wear on
these teeth as do the epoicotheriids (Rose,
1979).

Postilla 192

SUBFAMILY Propalaeanodontinae, new
Sole Included Genus

Propalaeanodon.

Diagnosis

Metacheiromyids with seven lower post-
canines.

Discussion

The Metacheiromyinae, Palaeanodon and
Metacheiromys, are united (relative to
Propalaeanodon) by the further reduction in
size and number of the postcanines and
form a tight clade. Propalaeanodon is the
plesiomorphous sister taxon of Palaeanodon
and Metacheiromys and thus is here placed
in the subfamily Propalaeanodontinae, of
equal rank with the Metacheiromyinae.

Propalaeanodon Rose, 1979, p. 2
Type Species

Propalaeanodon schaffi Rose, 1979, p. 3.
Included Species

Only the type species.

Distribution

Late Paleocene (late Tiffanian) of the Bighorn
Basin, Wyoming.

Discussion

Propalaeanodon, the oldest and most primi-
tive metacheiromyid, is distinguished by the
possession of seven lower postcanines
which are all single-rooted except for the
fourth which is double-rooted. The crowns of
the postcanines are higher and more pointed
than in Palaeanodon and the posterior medial
buttress of the mandible is prominent, but
less so than in Palaeanodon.

9 Metacheiromys and the Palaeanodonta Postilla 192

Propalaeanodon is known only from the
holotype dentary and possibly two left hu-
meri which Rose (1979) tentatively referred
to this genus. Except for differences in size,
these humeri are similar morphologically to
the humeri of Palaeanodon and
Pentapassalus (Rose, 1979).

SUBFAMILY Metacheiromyinae Wortman,
1903, p. 347, new rank

Included Genera
Palaeanodon and Metacheiromys.
Discussion

The metacheiromyines are united by the fur-
ther reduction in size and number of the
postcanines (five in the dentary of
Palaeanodon and two in the dentary of
Metacheiromys) relative to Propalaeanodon.

Note on Authorship of the Subfamily

Under the present rules of the International
Code of Zoological Nomenclature (Stoll et al.,
1964), the first author of any family-group
taxon (e.g., tribe, subfamily, family, super-
family) is credited with authorship of all
coordinate family-group taxa. Previously it
was customary (and this is still often done)
to credit authorship of a name to ‘‘he who
first published it with exactly the spelling
adopted in a given case” (Simpson, 1945,

p. 31; cf. Van Valen, 1966, p. 109). | find the
present rules ‘frequently unjust and confus-
ing’’ (Simpson, 1945, p. 31) and would prefer
the use of Simpson's (1945) criterion of au-
thorship cited above.

Palaeanodon Matthew, 1918, p. 621
Type Species

Palaeanodon ignavus Matthew, 1918, p. 622.

Included Species

The type species, P. parvulus Matthew,
1918, p. 640 and Palaeanodon sp. (Rose,
TS7SMh9Z9y 181):

Distribution

Late Paleocene and early Eocene
(Clarkforkian-Wasatchian) of the Bighorn
Basin, Wyoming and possibly the
Wasatchian of New Mexico (Simpson, 1931).

Discussion

Palaeanodon, well known from cranial and
postcranial material (see especially Matthew,
1918; Rose, 1978) is distinguished by the fol-
CaAkOA
oleae
canines large, oval in cross-section at the
base and enamel-covered; postcanines
small, peglike with rounded crowns and
separated by short diastemata; posterior
portion of jaw edentulous; large,
posteriorly-placed medial buttress and dis-
tinct internal mandibular groove present on
the dentary; and bullae incomplete.

P. parvulus is distinguished from P. ignavus
by its slightly smaller size (20—30% smaller).

lowing features: dental formula

Metacheiromys Wortman, 1903, p. 347
Discussion

This genus Is discussed in detail above

(pp. 2—8).

FAMILY Epoicotheriidae Simpson, 1927,

p. 285

Included Genera

Epoicotherium, Xenocranium, Tetrapassalus,

Pentapassalus, Amelotabes, Alocodontulum
and Tubulodon.

10 Metacheiromys and the Palaeanodonta Postilla 192

Discussion

The genera which have been included in the
Epoicotheriidae (listed above) appear to form
a paraphyletic group which includes both
primitive forms such as Amelotabes, that
lack any shared and derived character-states
for the family, and a few advanced forms
which are united relative to the
metacheiromyids and plesiomorphous
epoicotheriids on the basis of synapomor-
phies of the skull as the Epoicotheriinae (see
below). Thus, as used by previous authors
(e.g., Simpson, 1927; Colbert, 1942; Rose,
1978) the Epoicotheriidae has been diag-
nosed on the basis of shared primitive
character-states, especially of the lower jaw
(Rose, 1978, p. 669). Here | provisionally re-
tain the Epoicotheriidae as a family for all of
these forms; but | separate out
Xenocranium, Epoicotherium, Pentapassalus
and possibly Tetrapassalus as the
Epoicotheriinae. The remaining genera,
Amelotabes, Alocodontulum, and Tubulodon,
are presently too poorly known to adequately
assess their phylogenetic relationships and
are here regarded as Epoicotheriidae incer-
tae sedis.

SUBFAMILY Epoicotheriinae Simpson, 1927,
p. 285, new rank

Included Genera

Pentapassalus, Epoicotherium, Xenocranium
and possibly Tetrapassalus.

Discussion

The epoicotheriines are united as a clade by
the following synapomorphies: extremely
short and posteriorly broad skulls that are
triangular in dorsal and ventral view with high
and transversely wide occiputs, inflated
braincases, and medium to large, ossified
tympanic bullae. Epoicotherium,
Xenotherium, and possibly Tetrapassalus,

are further united by the derived character-

state of fusion of cervical vertebrae two
through five.

Pentapassalus Gazin, 1952, p. 32
Type Species

Pentapassalus pearci Gazin, 1952, p. 32.
Included Species

The type species and Pentapassulus woodi
(Guthrie, 1967, p. 23).

Distribution

Early Eocene (Wasatchian), La Barge fauna,
‘Upper Knight beds,’ Sublette County,
Wyoming (Gazin, 1952) and early Eocene,
Lysite Member of the Wind River Formation,
Fremont County, Wyoming (Guthrie, 1967).

Discussion

Gazin (1952) distinguished Pentapassalus by
the following suite of features: dental for-

?
mula aad teeth similar to Tubulodon (al-

though note that in the two holotypes and
sole known specimens of Pentapassalus the
crown morphology is worn off) except that
M, alone of the lower teeth is two-rooted or
bilobed; P, and Mz possess a single, conical
root; skull short and broad (similar to
Epoicotherium); bullae ossified, well inflated
and posterior in position; and pterygoids not
continuous with bullae. Pentapassalus wood!
(originally described as a species of
Palaeanodon, but referred to Pentapassalus
by Rose, 1978) is distinguished from P.
pearci by its slightly larger size (10-25%
larger in most linear dimensions of the post-
crania). The cheek tooth rows of P. pearci
and P. woodi are the same length, but the
canines in P. woodi are twice the size of
those in P. pearci. As Rose (1978) noted, this
is suggestive that P. pearci and P. woodi are
the female and male respectively of a single
species.

11 Metacheiromys and the Palaeanodonta Postilla 192

The holotypes of the two species of
Pentapassalus include skulls and partial

skeletons (Gazin, 1952; Guthrie, 1967; Emry,

1970; Rose, 1978, 1979). The postcranial
skeleton of Pentapassulus |s extremely simi-
lar in morphology to that of the
metacheiromyids.

Epoicotherium Simpson, 1927, p. 285
Synonym

Xenotherium Douglass, 1905, p. 204 (pre-
occupied by Xenotherium Ameghino, 1904,
p. 114)

Type Species

Epoicotherium unicum (Douglass, 1905, p.
204).

Included Species

The type species and possibly Epoicotherium
sp. of Heissig (1982).

Distribution

Early Oligocene (medial Chadronian),
‘“‘McCarty’s Mountain,’’ Madison County,
western Montana and the White River Group
in the Flagstaff Rim area of central Wyoming
(Emry, 1970, 1973; Rose and Emry, 1983);
possibly the early Oligocene near Pap-
penheim, West Germany (Heissig, 1982).

Discussion

For over 75 years only a single, nearly eden-
tulous skull, the holotype of Epoicotherium
unicum, had been described (Douglass,
1905; Simpson, 1927). Heissig (1982) has
recently described an edentulous left mandi-
ble with five alveoli from the early Oligocene
of West Germany which he assigned to
‘Epoicotherium sp.'’ Rose and Emry (1983)
subsequently described new material of
Epoicotherium from North America including
a complete skull, partial left dentary, miscel-

laneous vertebrae and the nearly complete
forelimb. Comparing Heissig’s (1982) de-
scription and illustration of the German
specimen to Rose and Emry’s (1983) de-
scription of the dentary of Epoicotherium
confirms that Heissig may be correct in his
identification, and thus this may represent
the first known non-North American
palaeanodont.

Epoicotherium bears an upper canine, five
upper postcanines, one lower incisor, a
lower canine, and five lower postcanines
(Rose and Emry, 1983). Simpson (1927,

p. 285) distinguished Epoicotherium by the
following features: ‘‘depressed snout,
domed occiput, slender but complete
zygomata without sub- and post-orbital pro-
cesses, large completely ossified tympanic
bullae, with which are ankylosed the
pterygoid plates, there being no hamular
processes, and cylindrical, one-rooted
cheek-teeth without enamel.’’ Rose and
Emry (1983) have since demonstrated that
Epoicotherium actually bore a very thin
enamel layer on at least the canines and
postcanines. The axis and following three
cervical vertebrae are fused in Epoicotherium
and throughout the skeleton bears numerous
subterranean, fossorial adaptations (Rose
and Emry, 1983).

Xenocranium Colbert, 1942, p. 3

Type Species

Xenocranium pileorivale Colbert, 1942, p. 3.
Included Species

Only the type species.

Distribution

Early Oligocene (Chadronian-?Orellan), Brule
and White River Formations, White River

Group, Wyoming and Nebraska (Rose, 1978;
Rose and Emry, 1983).

12 Metacheiromys and the Palaeanodonta

Discussion

Xenocranium, originally described from a
single skull and mandible, was distinguished
by Colbert (1942, p. 3) by the following fea-
tures: ‘‘much larger than Epoicotherium,
with a depressed snout and an elevated,
greatly broadened occiput; orbit without
postorbital processes; bullae transversely
elongated and prominent below level of the
basicranium; very large, bulbous expansions
of the squamosal external to the bullae and
at the posterior termination of the zygomatic
arch; mandible shallow, with a broad, inter-
nal shelf; teeth simple and peg-like, without
enamel; five cheek teeth in the maxilla and
six in the mandible, of which the anterior
(canine) In each jaw is much larger than the
rest of the teeth.”

Rose and Emry (1983) have since rede-
scribed the skull and mandible, and have de-
scribed the anterior half of the axial skeleton
and most of the forelimb of Xenocranium.
Rose and Emry (1983) demonstrated that the

dental formula of Xenocranium is oe (i.e,
there |s actually a small incisor anterior to the
canine in the lower jaw). The snout of
Xenocranium (missing in the holotype) |s flat-
tened and expanded anteriorly. As in
Epoicotherium, and possibly Tetrapassalus
(see below and Fig. 11), cervical vertebrae
two through five are fused in Xenocranium
and the skeleton is more highly specialized
for subterranean, fossorial habits than in any
other known palaeanodont (Rose, 1978;
Rose and Emry, 1983).

Tetrapassalus Simpson, 1959, p. 2
Type Species

Tetrapassalus mckennai Simpson, 1959,
jon 2.

Included Species

The type species and TJetrapassalus proius
West; 1973, p. 929.

Postilla 192

Distribution

Middle Eocene (Bridgerian) of the Bridger
Formation, Bridger Basin, Wyoming.

Discussion

Tetrapassalus, described only from the two
holotype partial lower dentitions and dentary
fragments, is distinguished by the following
features: lower canines large; cheek teeth
consisting of four subequal, cylindrical, peg-
like postcanines without closed roots or root
division, but showing distinct occlusal wear;
and posterior medial buttress slight. T. proius
iS distinguished from T. mckennai by its
smaller size (approximately two-thirds the
size of T. mckennai).

A maxilla and two fused cervical verte-
brae series are tentatively referable to
Tetrapassalus and are discussed below.

cf. Tetrapassalus sp. A
Synonymy

cf. Tetrapassalus sp.: Rose, 1978, p. 672,
text-fig. 5

Distribution

Middle Eocene (early Uintan) of the Tepee
Trail Formation, northwestern Wyoming.

Discussion

Rose (1978) described and illustrated a right
maxilla (AMNH 10215) of a small
epoicotheriid which may represent
Tetrapassalus, or perhaps more likely, a new
genus and species. AMNH 10215 bears a
large, pointed canine and four small, single-
rooted postcanines (although the second Is
missing from the specimen) with enamel-
covered crowns, except for the occlusal sur-
faces (Rose, 1978).

13 Metacheiromys and the Palaeanodonta

Postilla 192

cf. Tetrapassalus sp. B
(Fig. 11)

Synonymy

?Order Edentata: Robinson, 1963, p. 6, un-
numbered fig.

Epoicotheriid: West, 1973, p. 931

“fused cervical vertebrae:'’ McKenna, 1975,
p. 29

“Tetrapassalus or a. closely related form:"
Rose and Emry, 1983, p. 42

Referred Specimens

YPM 14919, the fused centra of vertebrae
two through five (Fig. 11): collected by L.
LaMothe from middle Eocene-aged strata,
probably upper Bridger beds, of the Bridger
Formation at Lone Tree, Wyoming in 1873.

YPM 16872, a specimen identical to YPM
14919 but preserving only the centrum of
the axis and part of the centrum of vertebra
three (this specimen is listed by Robinson,
1963, but | have not been able to locate it in
the YPM collections): collected by J. Heisey
from middle Eocene-aged strata, upper
Bridger beds of the Bridger Formation at
Lone Tree, Henry's Fork, Bridger Basin,
Wyoming, on 20 June 1874.

Discussion

The suggestions by Robinson (1963) and
West (1973) that YPM 14919 and YPM
16872 represent the fused cervical vertebrae
of an epoicotheriid are corroborated by the
recent description of fused cervical vertebrae
in Epoicotherium and Xenocranium by Rose
and Emry (1983, p. 42) who refer YPM
14919 and YPM 16872 to ‘'Tetrapassalus or
a closely related form’ on the basis of size.
The cervicals are unfused in the
metacheiromyids (e.g., see Fig. 11, J; the
axis of Metacheiromys marsh).

Epoicotheriidae Incertae Sedis
Amelotabes Rose, 1978, p. 659

Type Species

Amelotabes simpsoni Rose, 1978, p. 660.
Included Species

Only the type species.

Distribution

Late Paleocene (Tiffanian) of the Bighorn
Basin, Wyoming.

Discussion

Amelotabes simpsoni, known from a single
dentary and partial lower dentition, |s distin-
guished by the following features: mandible
shallow, robust with medial buttress and
internal mandibular groove; dental formula
Ue
2 ae
P5-M, double-rooted; cheek teeth with thin
enamel on occlusal surfaces; Pz, with large
protoconids, small, low paraconids and slight
protocristids; P3 with small talonid heel; mo-
lars with primitive eutherian cusp pattern;
molars low crowned with bulbous and poorly
defined cusps; protoconids largest and high-
est cusps on the molars; and hypoconulids,
cristids obliquae and cingulids absent.

; canines large; P, single-rooted;

Alocodontulum Rose, Bown and Simons,
1978, p. 1162

Synonym

Alocodon Rose, Bown and Simons, 1977,
p. 1 (preoccupied by Alocodon Thulborn,
1973, p. 93)

Type Species

Alocodontulum atopum (Rose, Bown and
Simons, 1977, p. 2).

Included Species

Only the type species.

14 Metacheiromys and the Palaeanodonta

Distribution

Early Eocene, upper ‘’Gray Bull’ beds, lower
Willwood Formation, Bighorn Basin,
Wyoming.

Discussion

Alocodontulum is known only from the
genoholotype, an incomplete premaxilla-
maxilla and partial upper dentition. Rose,
Bown and Simons (1977, p. 2) diagnosed
this taxon as follows: ‘‘Upper molars longer
than wide, and uniquely specialized; M'
with median longitudinal furrow, several
cusps arranged In line on lingual and buccal
borders of crown, and no enamel on top of
crown. M' slightly larger than M?, both much
larger than M8; M8 greatly reduced, single-
rooted, with very low and bulbous crown. P?
premolariform, with large paracone,
rudimentary metacone, small low protocone.
P' tiny, Single-rooted. Canine of moderate
size, triangular in section.”

Rose, Bown and Simons (1977) assigned
Alocodontulum to the Epoicotheriidae primar-
ily on the basis of the following similarities
that it shows to either Pentapassalus or
Tubulodon or to both: enamel reduction on
the teeth (occlusal surfaces of the cheek
teeth lack enamel); similar scalloped margins
on the molars of Alocodontulum and Tubulo-
don; upper molars longer than wide; M$ peg-
like; and upper canine triangular in cross sec-
tion with the anteromedial face honed and
lacking enamel.

Tubulodon Jepsen, 1932, p. 264
Type Species

Tubulodon taylori Jepsen, 1932, p. 264.
Included Species

Only the type species.

Postilla 192

Distribution

Late early Eocene (Lostcabinian) of the Lost
Cabin Member, Wind River Formation, Wind
River Basin, Wyoming.

Discussion

Originally thought by Jepsen (1932) to be re-
lated to the extant aardvark (Orycteropus,
Tubulidentata), Tubulodon, known only from
partial lower dentitions (Jepsen, 1932;
Guthrie, 1971) is distinguished by the follow-
ing features: cheek teeth similar to those of
Amelotabes with low and marginally situated
cusps; three lower molars present (P, only
known premolar); known teeth double-
rooted with hypsodont, columnar crowns;
cheek teeth with thin enamel on the sides
and lacking enamel on the occlusal surfaces.
The genoholotype of Tubulodon has micro-
scopic tubules present in the teeth and
Jepsen (1932) considered these tubules to
indicate a relationship to the Tubulidentata.
Colbert (1941) argued that the tubules seen
in Tubulodon are unlike those seen in
Orycteropus and allies, whereas both Gazin
(1952) and Rose, Bown and Simons (1977)
have observed similar tubules in the teeth of
other Eocene mammals. Rose, Bown and
Simons (1977; cf. Peyer, 1968) note that
dentine tubules are present in the teeth of
most mammals and these authors suggest
that tubules may merely be more readily
seen in some fossil mammals in which the
enamel is thin (e.g., Tubulodon,
Alocodontulum and Pentapassalus).

15 Metacheiromys and the Palaeanodonta_ Postilla 192

Conclusions

Fourteen species, ten genera, three subfami-
lies and two families are formally recognized
within the order Palaeanodonta (Table 3).
The earliest known palaeanodonts are
Amelotabes and Propalaeanodon, both from
the Tiffanian of the Bighorn Basin, Wyoming.
Whereas Amelotabes appears to be the
most primitive known palaeanodont, and
may thus approximate the ancestral
palaeanodont morphotype, Propalaeanodon
bears derived metacheiromyid features. The
latest and most derived palaeanodonts are
Epoicotherium and Xenotherium from the
early Oligocene. Traditionally the
Palaeanodonta have been regarded as a
wholly North American group; however, the
recent referral of a specimen from the early
Oligocene of West Germany to
Epoicotherium sp. (Heissig, 1982) suggests
that further collecting may extend the geo-
graphic and stratigraphic range of this poorly
known mammalian order.

Acknowledgments

| thank John H. Ostrom (YPM) for allowing
me to study specimens in his care and Mary
Ann Turner (YPM) for help in locating speci-
mens and locality information. | thank John
H. Ostrom and Bruce H. Tiffney for critically
reviewing the final manuscript. | wish to ex-
press my appreciation to Cynthia B. Pettit,
John W. Pendleton and Deborah A. Shea for
their encouragement while | was working on
this paper during the spring and summer of
1982.

Table 3

A classification of the Palaeanodonta.

Order Palaeanodonta
Family Metacheiromyidae
Subfamily Propalaeanodontinae
Propalaeanodon (1 species)
Subfamily Metacheiromyinae
Palaeanodon (2 species)
Metacheiromys (2 species)
Family Epoicotherlidae
Subfamily Epoicotheriinae
Pentapassalus (2 species)
Epoicotherium (1 species)
Xenocranium (1 species)
Tetrapassalus (2 species)
Epoicotheriidae incertae sedis
Amelotabes (1 species)
Alocodontulum (1 species)
Tubulodon (1 species)

16 Metacheiromys and the Palaeanodonta Postilla 192

Literature Cited

Ameghino, F. 1904. Nuevas especies de mamiferos, cretaceos y terciarios de la Republica Argentina.
An. Soc. Cien. Argentina (Buenos Aires) 56—58:1—142.

Colbert, E. H. 1941. A study of Orycteropus gaudryi from the island of Samos. Bull. Am. Mus. Nat. Hist.
78:305—51.

1942. An edentate from the Oligocene of Wyoming. Not. Nat. Acad. Nat. Sci. Philadelphia, No.
109: 1—16.

Cope, E. D. 1889. The Edentata of North America. Am. Nat. 23:657—64.

Cuvier, G. L. C. F. D. [1798]. Tableau élementaire de |'histoire naturelle des animaux. Paris, J. B.
Bailliere, 710 pp.

Douglass, E. 1905. The Tertiary of Montana. Mem. Carnegie Mus. 2:203-8.

Emry, R. J. 1970. A North American Oligocene pangolin and other additions to the Pholidota. Bull. Am.
Mus. Nat. Hist. 142:455—510.

1973. Stratigraphy and preliminary biostratigraphy of the Flagstaff Rim area, Natrona County,
Wyoming. Smithson. Contrib. Paleobiol. 18:1—43.

Gazin, C. L. 1952. The Lower Eocene Knight Formation of western Wyoming and its mammalian faunas.
Smithson. Misc. Collect. 117:1—82.

Gill, T. 1872. Arrangement of the families of mammals with analytical tables. Smithson. Misc. Collect.
11:1-98.

Grasse, P. 1955. Ordre Edentes. /n Traité de Zoologie (P. Grassé, ed.) 17:1182—1266. Paris.

Guthrie, D. A. 1967. The mammalian fauna of the Lysite Member, Wind River Formation, (Early Eocene)
of Wyoming. Mem. South. Calif. Acad. Sci. 5:1—53.

1971. The mammalian fauna of the Lost Cabin Member, Wind River Formation (Lower Eocene) of
Wyoming. Ann. Carnegie Mus. 43:47—113.

Heissig, K. 1982. Ein Edentate aus dem Oligozan Suddeutschlands. Mitt. Bayer. Staatssamml. Palaeon-
tol. Hist. Geol. 22:91—96.

Jepsen, G. L. 1932. Tubulodon taylori, a Wind River Eocene tubulidentate from Wyoming. Proc. Am.
Philos. Soc. 71:255—74.

Linnaeus, C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species
cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. Stockholm, Laurentii Salvii,
vol. 1, 824 pp.

Matthew, W. D. 1909. The Carnivora and |nsectivora of the Bridger Basin, Middle Eocene. Mem. Am.
Mus. Nat. Hist. 9:291—567.

1918. A revision of the Lower Eocene Wasatch and Wind River faunas, Part 5, Insectivora (con-
tinued), Glires, Edentata. Bull. Am. Mus. Nat. Hist. 38:565—657.

McKenna, M. C. 1975. Toward a phylogenetic classification of the Mammalia. /n Phylogeny of the Pri-
mates (W. P. Luckett and F. S. Szalay, eds.). Plenum Press, New York, pp. 21—46.

Osborn, H. F. 1904. An armadillo from the middle Eocene (Bridger) of North America. Bull. Am. Mus.
Nat. Hist. 20:163—5.

Parker, T. J. and W. A. Haswell. 1897. A Text-book of Zoology. London, MacMillan and Co., vol. 2, 683
pp.

Peyer, B. 1968. Comparative odontology. Univ. Chicago Press, Chicago, 347 pp.

Robinson, P. 1963. Fused cervical vertebrae from the Bridger formation (Eocene) of Wyoming. Univ.
Colo. Stud., Ser. Geol. 1:6—9.

Rose, K. D. 1978. A new Paleocene epoicotheriid (Mammalia), with comments on the Palaeanodonta. J.
Paleontol. 52:658—74.

1979. A new Paleocene palaeanodont and the origin of the Metacheiromyidae (Mammalia). Bre-
viora 455:1—-14.

1981. The Clarkforkian land-mammal age and mammalian faunal composition across the
Paleocene-Eocene boundary. Univ. Mich., Pap. Paleontol. 26:1—197.

17 Metacheiromys and the Palaeanodonta_ Postilla 192

Rose, K. D., T. M. Bown and E. L. Simons. 1977. An unusual new mammal from the early Eocene of
Wyoming. Postilla 172: 1—10.

1978. Alocodontulum, a new name for Alocodon Rose, Bown and Simons, 1977, non Thulborn,
1973. J. Paleontol. 52:1162.

Rose, K. D. and R. J. Emry. 1983. Extraordinary fossorial adaptations in the Oligocene palaeanodonts
Epoicotherium and Xenocranium (Mammalia). J. Morphol. 175:33—56.

Simpson, G. G. 1927. A North American Oligocene edentate. Ann. Carnegie Mus. 17:283—98.

1931. Metacheiromys and the relationships of the Edentata. Bull. Am. Mus. Nat. Hist. 59:295—

381.

1945. The principles of classification and a classification of the mammals. Bull. Am. Mus. Nat.
Hist. 85:1—350.

1959. Anew middle Eocene edentate from Wyoming. Am. Mus. Novit. 1960: 1—8.

Stoll, N. R., R. P. Dollfus, J. Forest, N. D. Riley, C. W. Sabrosky, C. W. Wright and R. V. Melville.
1964. International Code of Zoological Nomenclature. International Commission on Zoological Nomencla-
ture, London, 176 pp.

Szalay, F. S. 1977. Phylogenetic relationships and a classification of the eutherian Mammalia. /n Major
Patterns in Vertebrate Evolution (M. K. Hecht, P. C. Goody and B. M. Hecht, eds.). New York, Plenum
Press, pp. 315-74.

Thulborn, R. A. 1973. Teeth of ornithischian dinosaurs from Upper Jurassic of Portugal. Mem. Serv.
Geol. Portugal 22:89-134.

Van Valen, L. 1966. Deltatheridia, a new order of mammals. Bull. Am. Mus. Nat. Hist. 132: 1-126.
Weber, M. 1904. Die Saugetiere. Einfuhring in die Anatomie und Systematik der recenten und fossilen
Mammalia. Jena, Gustav Fischer, 866 pp.

West, R. M. 1973. An early middle Eocene epoicotheriid (Mammalia) from southwestern Wyoming. J.
Paleontol. 47:929—31.

Wortman, J. L. 1903. Studies of Eocene Mammalia in the Marsh Collection, Peabody Museum. Am. J.
Sci. 16:345—-68.

The Author

Robert Milton Schoch. Department of
Geology and Geophysics and Peabody
Museum of Natural History, Yale University,
170 Whitney Avenue, P.O. Box 6666, New
Haven, CT 06511.

Postilla 192

18 Metacheiromys and the Palaeanodonta

‘eindeos jybu jeued

EN6ZL Wd A ‘Maid jeIpaw “sed
diyudeiBoyoydoaiejs (Wy !ejndeos
yyHu jeed ‘EQ6ZL WdA ‘Mala
jeiaje] ‘Wied o1lydesHoyoydoae}s

(7 ‘G6 JUuBley ‘ejndeos jybu yo
Ayiaeo ploua|b ‘SQ6ZL WdA ‘M@iA
jeisip ‘ued o1ydes6ojOydoee}s

(y ‘SIxXe 'EOBZL WdA ‘M@lA |e} U8A
‘ned a1udeiboyoyudosiea}s (7 ‘p71

YIPIM ‘sIxe “E06ZL WdA ‘MBIA
jesiop ‘uied o1ydeiHo}Oydoese}s

(/ ‘@UIUeD 1a] "EO6TL WdA ‘MAIA
jenBul| (H 'Z° LL yybue) ‘auiued

42] “CO6ZL WdA ‘Mai jelge| (5
‘aulued UM JUaWUbely Aue||IxelU

1UBU ‘SOBZL WdA ‘Maia jenbul|

(4 ‘O° ZL y}bHue| pevveseid win
-1xeW ‘@ulued Y}IM JUaWUbe, Ale|
-xeu YYBU "EOBTZL WA ‘1e!G2! (F
‘6 Z| JUBIey periesaid WuNWUIXeLU
‘Ase}uap 9] JO JUaWHely 10198}
-Sod ‘ZOGEL WdA ‘M@lA |elge| ‘led
diudeiHbojoydoaiays (g ‘Aue}uep
H9] ‘SOBTL WdA ‘Mala jenbull (D
‘AleUSP 149] ‘EOBZL WdA ‘MSlA
leige| (g ‘80 YyybHua ‘(adAjO}

-99|) Auejuap 49] “E0671 WdA
‘MBIA |ESN|990 ‘Wed d1ydeiHo oud
-09191S (yy :zZ x Ajayewulxoudde
Saini je Wysselu SAWOUIaYIELAay=
41 614

‘

Postilla 192

19 Metacheiromys and the Palaeanodonta

“Snuauuny jYyBu 4O pus je}sip
‘SOBZL WdA ‘M@IA JOUE}sSod ‘ied
diydesBoyoydoasa}s (gq !sniawuny
1UBu $O pua jewuixoid ‘eggzl
WdA ‘M@IA JOUe}SOd ‘Ied d14de1b
-o}OYdoOaIa}s (9 '1'°1Z UIpIM
wunuuIxelW ‘SniauuNny YH JO pus
IEISID “COBZL WdA ‘MAlA JOE}
-ue ‘i1ed diydeiHboyoydoaials (g
‘OTL UPIM WuNLUIxelW ‘SnJaWNY
YH yo pus jeulxoid ‘EQEZL WdA
‘MAIA JOWA}Ue ‘Wed o1yde1Hojoud
-08191S (7 :Z x Ajayeuixoidde
SaInBiy Je WysseLu SALWOIIAYOEJAa-=y
42 ‘614

20 Metacheiromys and the Palaeanodonta Postilla 192

“eujn 8] “Z9007 WdA

‘M@AIA JOUE}Ue ‘Wed d1yudeiHbo}oud
-09/9}S (J ‘| 9p yHua ‘eujn 49]
‘£9007 WdA ‘M@lA |elpeuw ‘sed
olydeiHboyoydosieys (g ‘eujn 1ybu
JO Pua |EISID "EOBTL WdA ‘MalA
Jouajue ‘Wed o1ydeiHo0}OydoaJe}s
(2 ‘eujn 1YyBu 4O pua jeisip “E0671
dA ‘Mala jeIpew (g ‘0'9E YyIbuUE|
peAleseid winwixeu ‘eujn 1Yybu
JO pua |e1SIP "COBZL WdA ‘Mair
je1aye| (\v :Z x Ajayeuuixoidde
SOINBY |Je TySuelU SAWOIIaYIeEJAaYWy

4¢ bi

“INWUA} YO}

}O PUB |EISIP "ZOGEL WdA ‘MalA
Jou9a}sod ‘Wed o1lydeiboOydoe9)}s
(H ‘4INWe9} 19] $O DUS jeLUIXOJd
‘OOGEL WdA ‘M@IA 10Ua1SOd ‘Jed
a1ydeiboyoydoaiajs (5 ‘snipes

148] JO pus jeWIxO1d '/900b WdA
‘MBIA jesa}e| ‘Wed d1ydeiBoyoud
-08198}S (4 'GE| yHus| pevies
-81d WNWIXeLW ‘SNIPes 149] JO

pus jewIxoid '/900P WdA ‘MAIA
Jouaysod ‘ied o1ydeiHoj0ydoe18}s
(J ‘unwe} Ya} JO pua jeysip
‘'ZOGEL WdA ‘MIA Jouajue ‘ed
oiydesBoyoydoaiays (g ‘unweay

148] JO pu jeUIxOJd ‘QOGEL WdA
‘MAIA JOWA}Ue ‘Wed d14deiHojoud
-098191S (9 ‘ppl YIPIM ‘NWA

149] JO pus jeLUIXOJd ‘OOGEL WdA
‘MAIA |eWUIXOId ‘Wied o1lydeiHoyoUd
-O9191S (G ‘7 pL YIPIM ‘INWAay

148] JO PUd |EISIP ‘ZOGEL WdA
‘MBIA |e}SIP ‘Wed d1ydei6o oud
-O919}S (7 °Z x Ajayewixoudde
SainBi je Wysselu SALWOUIAYOeJAaP=y

<4 614

Postilla 192

4

jy

Metacheiromys and the Palaeanodonta

2]

Postilla 192

22 Metacheiromys and the Palaeanodonta

eight 9}
JO Pua |EISID "LOGEL WdA ‘MIA
jeysip ‘sed d1ydesBoyoydosiajs (4
‘elqi, 146 JO pua jeulxoid ‘| QGEL
Wd ‘M@iA jeuuixoud ‘ied o1udeib
-0}0YdOSI9}S (F ‘e1gi} 149} }o pua
JEYSID “LOGEL WdA ‘MBIA 1019}
-sod ‘s1ed d1udeiboyoudoaisals (g
‘elqi 1UBu $O pue jewixoid ‘| QGE|
WdaA ‘Maid 10U98}S0d ‘Jed diydei6
-O}OYdoOaIa}S (9 ‘6 OL YIPIM

‘Blgit YO] JO Pus |eISIP “LOGEL
WdA ‘M@IA JoUajue ‘Wed o1ydesb
-O}OYUdOSI91S (g ‘OE YIPIM ‘elgi
}UHuU yO puae jewIxOid 'LOGEL WdA
‘MAIA JOUB}Ue ‘Wed O1lydeiHojoud
-0919}S (VW :Z x Ajeyewixoidde
SOINBI |e TYSIeLU SAWOLIAYIELB\y
4g ‘614

Postilla 192

23 Metacheiromys and the Palaeanodonta

‘elqiy yUuBu

}O PUd |EISIP ‘EO6BTL WdA ‘M@IA
Jouaysod ‘sed o1ydes6oyoydoase}s
(4 ‘eiqi }yBu fo pue jewixoid
‘SOBZL WdA ‘MalA JoWe}sod ‘sed
a1ydeiBojoyudoae}s (FZ ‘elqn 1Yybu
JO pua |eISIP 'EO6ZL Wd A ‘MSA
Jousjue ‘Wed o1lydesHojOydoese}s
(g ‘eign yuBu yo pue jewixoid
‘SOBZL WdA ‘MaIA JoWejuUe ‘ed
oiydeiboyoydoeiels (9D ‘6 UIPIM
‘eiqiy }UBU JO pusa jelsip ‘SOBZL
dA ‘Maia jeysip ‘ued o1ydes6
-0]}0Ydo91a}S (g ‘6’ pL YIPIM ‘eqn
1UBu JO pus jewIXOld ‘'EO6ZL WdA
‘MAIA jeWUIXOId ‘Wed o1ydeibo}oyd
-O819}S (7 :Z x Ajayeuixoidde
SainBij je ‘ayeulue}epul seloeds
pue snuab ‘sayewid Jep1O

<9 614

Postilla 192

24 Metacheiromys and the Palaeanodonta

9°77 UBue| perreseid Wun!
-xeW ‘UNIONS 'EQGEL WdA ‘MBIA
jed]USA ‘Wed dIydesHojOYydoaJ9}s
(9 ‘6 Lz yyBue| perreseid Wun
-IXeWW ‘SIAJAd JO Wed Jej;nqejeoe
YOU ‘COBTL Wid A ‘MAlA jes9}e|
‘ured diudeuBoyoudoeiels (g ‘eS pr
ujBug| ‘siAjad $o Wed Jejngqejaoe
pue wij! }yHU ‘SOGEL WdA ‘Maia
jesaie| ‘Wed o1ydei6o}oydoee}s
(vy :z x Ajeyeuixoudde seunbi

We (D ‘v) 1ysuew SAWOIIAYIEJBy
pue (g) eyeuluajepul seioeds
pue snueb ‘sayewld JapiC
42614

Postilla 192

25 Metacheiromys and the Palaeanodonta

(||.

y}6Hua| ‘snuewé Jo yiHiIp paula}
-apun Jo xuejeud jenBun ‘| Qgg¢EL
WdA ‘MalA apis ‘sied oludei6
-o}OYdoaals (4 ‘ep ubHu9| ‘sed
$0 }IHIP paulwayapun Jo xuejeyd
PUODSS 'LOGEL WdA ‘M@aIA |esiop
‘sed dIydesHoyoyudoaiays (FZ ‘G9
yjHu9| ‘sed jo 1161p pauluuajep
-un yo xuejeyd Isdly “LOGEL WdA
‘MAIA jeSiop ‘ied olydeiBoyoud
-0819}S (Q '0' Lp yjBue| panies
-9/d WunwixelW ‘SIAjed Jo ped
Jejngejaoe pue Wwnij! Ya} ‘Wunuoes
‘ZOGEL WdA ‘M@iA jesiop ‘ied
dludeiHoloydosiajs (9 ‘sed jubu
jeled ‘LOGEL WdA ‘M@IA [e1]U9A
‘ued diudesHoyoudosials (g ‘1 LE
ujbHue| peAiasaid Winuuixew ‘sed
1yubu jeed ‘LQOSEL WdA ‘MAI
jesiop ‘sed o1ydesBoyoydoase}s
(7 :G | x Ajayewixoudde si yoiuM
J 1deoxe Z x Ajayewixoidde
SaINBly je TysuelU SAWOLIAYIEEWy

43 614

Postilla 192

26 Metacheiromys and the Palaeanodonta

y , 4 e , sare; > ; ;
p 7 : Ps «iS we hear,

pv Lg sjepneo uaneas sul}
JO YjHue| ‘aeiqauaA jepned uanas
}SJIJ PUB LUNIYOS! Ys| “LOGEL WdA
‘MBIA |E1]UBA 'Gp | x Ajeleuw
-Ixoidde ‘1ysuelu SAWOLIAYIEJBW
<6 614

Postilla 192

27 Metacheiromys and the Palaeanodonta

‘sad ya] $0 1161p puooes

jo xuejeud ys} ‘69007 WdA ‘MaiA
jE1]UBA ‘Wied OIudesHOOYdosie}s
(4'G OL Uybusa| ‘sad 149) $0 1HIp
PuOdeS }O xUe|eUd ISU ‘E900L
WdaA ‘Mal jessop ‘ued o1ydes6
-oJOYdoaa}s (F !piogno jyubu
‘8900 WdA ‘MAIA jelpauu ‘ied

— o!ydeibojyoyudoaiajs (g ‘snjebeise

1UBU ‘8900r WdA ‘MBIA |e1]U8A
‘ured oiydesHoyoydoaials (9 ‘OZ
yy6u9} Winuuixew ‘plogno jybu
‘89000 WdA ‘Mai Jessop ‘ied
diydesHooydoadials (g '8°8 peey
JO JoJaUWUeIP LUNWUIXeWW ‘snjebel}
-Se IY ‘89007 WdA ‘Main
jesiop ‘ued d1ydeiHBoyoydoee}s
(viz x Ajayewixoudde sounbiy

je ‘sndAsep sAwosayoejayy)

401 ‘614

SMITHSONIAN TW LIBRARIES
3 9088 01206 5140

Postilla 192

‘MAIA 1OL81SOd ‘ied o1ydes6
-0}0YdO919}S (4 !MPIA 10198] Ue
‘ued aiydesHoyoyudosiels (FZ ‘MaiA
je19}e| 9} ‘Wied o1ydesHoyoud
-081981S (Gg ‘M@AIA |e19}e| 1YHU

‘sed o1ydeiHoyOUdosals (9D !MaIA
JE1]USA ‘Wed d1ydesHo,OYUdoaJs)}s
(g (M@IA Jessop ‘Jed o1ydei6o,oud
-O8191S (iV :p x Ajeyeuuixoidde
seinby ye ‘9° | | yyGue) WunuuIxeW
‘QAly UBNOIU} (SIXe) OM) SEIGSUSA
JEOIAIA@D JO B1]US9 PESny ‘6L6r 1
WdA ‘g ‘ds snjessedena) }9
<4ut 614

28 Metacheiromys and the Palaeanodonta