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Life Sciences Contributions "IHC
Royal Ontario Museum I \\J

Tertiary Mammals
of Saskatchewan
Part IV: The Oligocene
Anthracotheres

LorisS. Russell

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Kayser, C.

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LIFE SCIENCES CONTRIBUTIONS
ROYAL ONTARIO MUSEUM
NUMBER 115

LORis S.RUSSELL Tertiary Mammal s

of Saskatchewan
Part IV: The Oligocene
Anthracotheres

Publication date: 20 March 1978

ISBN 0-88854-210-0

ISSN 0384-8159

Suggested citation: Life Sci. Contr.. R. Ont. Mus.

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Tertiary Mammals of Saskatchewan
Part IV: The Oligocene Anthracotheres

Abstract

The new species Bothriodon advena is described on the basis of
the maxillae with both tooth rows, a left maxilla with teeth, and
an incomplete mandible with most of both tooth rows. These are
from the Lower Oligocene Cypress Hills Formation of Sas-
katchewan. The species can be distinguished by dental charac-
ters from B. rostratus and the various European species, but has
its closest resemblance to B. velauniis (von Meyer) from the
Oligocene of Ronzon, France. The two North American species
clearly belong to Bothriodon, as distinct from Aepinacodon
Troxell, known from at least two other American species.

Introduction

The Anthracotheriidae are a family of "bunoselenodont" artiodactyls known
from the Late Eocene to Early Miocene of Europe, the Early Oligocene to
Early Miocene of North America, and the Miocene of Africa and Asia. They
are distinguished by relatively small, well-spaced anterior teeth, and large,
close-spaced, more or less rectangular molars. In both upper and lower molars
the labial cusps are crescentic or V-shaped, whereas the lingual cusps are
conoid or pyramidoid. The upper molars have a well-developed protonocule
but no metaconule. The shape of the skull and the spacing of the teeth vaguely
suggest the camels, but there is nothing cameloid in the limbs, which have four
short digits, with small, almost pointed ungual phalanges.

Because of bibliographic confusion in the European literature, North Ameri-
can students of this family have used a variety of generic names in trying to
place American species in European genera. The first attempt to introduce
some order was by Troxell (1929), who noted that the name Bothriodon
Aymard (1846), contrary to long-standing assumption, had chronological prior-
ity ovQV Ancodon (Ancodus) Pomel (1847) and Hyopotamiis Owen (1848). The
last-mentioned name had already been shown by Matthew (1909) to have been
preoccupied by Kaup in 1844. Troxell cited a number of differences between
the American species referred to Bothriodon (or Ancodus) and the European
species of that genus, and proposed that the former be separated in a new
genu s , A epina codon .

Troxell's conclusions were accepted in part by Scott (1940), who recognized
various differences between the European and American species of Both-
riodon, but concluded that these did not justify separation of the latter as a
distinct genus, Aepinacodon. However, Macdonald (1956) revived TroxelFs

genus on essentially the same grounds as that author used, and included A.
amcncaniis (Leidy), A. dejiectus (Marsh), and A. rostratus (Scott) as the
constituent species.

In comparing the American and European species that have been referred to
Bothriodon or Aepimicodon, I find that the main distinctions are between B.
amcriccinits and B. deflect us on the one hand, and B. rostratus and the Euro-
pean B. velaunus (von Meyer), B. leptorhynchus Aymard, ^. ciymardi (Pomel),
and B. hovinus (Owen) on the other. I would therefore restrict the genus
Aepincicodon to include A. deflectus (type) and A. americanus, and assign B.
rostratus to Bothriodon s.s. along with the European species. The new species
from Saskatchewan, described below, is also referred to Bothriodon s.s.

The first report of anthracothere remains from Saskatchewan was by Lambe
(1905), who later described and illustrated the specimens in detail (Lambe,
1908). These consisted of a well-preserved right M-, a left P\ a right lower
canine, and two left lower incisors. Lambe referred the molar to Ancodus
brachyrhynchus (Osborn and Wortman), and the other teeth with question to
the same species. He also described and illustrated an incomplete tooth which
he designated as the upper molar of Anthracotheriuml pygmaeum, sp. nov.
The elongate outline of the crown and the broadly concave lingual margin, as
well as the small size, make it unlikely that this specimen represents an
anthracothere, but at present I am unable to offer a more appropriate reference.

In recent years good anthracothere dentitions have been collected from the
Cypress Hills Formation (Lower Oligocene) in the valley of Calf Creek, Sas-
katchewan, and these are the principal subjects of the present contribution.

Systematic Description

Order Artiodactyla

Family Anthracotheriidae Leidv

Bothriodon Ay mar d 1846

SYNONYMS. Ancodon {Ancodus) Pomel 1847; Hyopotamus Owen 1848.

GENERIC DIAGNOSIS

Anthracotheres of medium size. Snout elongate, concavely attenuate between

canines and cheek teeth; cheek region expanded laterally. Dentition ' ;

incisors subequal, bluntly spatulate; canine small to tusk-like, more or less
compressed, long diastema between C and P'; P' and P-^ trianguloid in side
view, compressed, with short diastema between; P"* ovoid to trianguloid in
crown view, with large principal cusp; P'* short, with large labial and smaller
lingual cusp. Upper molars rectanguloid, with rounded corners, outline wider
transversely than anteroposteriorly; paracone and metacone high, pointed,
each with narrow V-shaped crest, the posterior arms of which terminate at the

labial margin; protocone conoid, with weak crests; hypocone also conoid but
with V-shaped crest having flattened area between arms; protoconule (unworn)
as high as protocone, with crest extending anterolabiad; labial margin trilobate,
with small, pointed parastyle, large mesostyle bulging prominently labiad, and
small metastyle; little or no external cingulum; moderate anterior and posterior
cingulum, extending a short distance onto lingual side; deep, almost straight
transverse valley between protocone, protoconule, and paracone in front,
hypocone and metacone behind, this valley extending into the mesostyle as a
broadly rounded or bluntly pointed notch; sides of principal cusps vertically
striated, especially the protocone.

Mandible attenuate, but unlike maxillae, the tooth rows are nearly parallel
for entire length. Canine procumbent in socket but with dorsad-curved crown;
P, single-rooted, with moderate diastema between it and canine; P2 double-
rooted, crown trianguloid in side view, relatively long diastema between it and
?,; P3 similar to P2 but larger, with incipient talonid and strong posterolabial
cingulum; no diastema between P2 and P3; P4 a little wider than P3, with slightly
larger talonid; M, with high, conoid metaconid and entoconid, and lower,
V-shaped protoconid and hypoconid; transverse valley between trigonid and
talonid opens lingually as well as labially ; M2 similar to M, but a little larger; M3
similar to M2 but with large hypoconulid spur, which is directed posterolabiad,
the hypoconulid being similar to, and almost as large as, the hypoconid.

TYPE SPECIES. Anthracotherium velaunus von Meyer; Oligocene, Ronzon,
Haute Loire, France.

DISCUSSION

The genus Aepinacodon, proposed by Troxell (1921) for the American species
referred to Bothriodon, is here restricted to ''Bothriodon'' deflectiis (Marsh)
and ''B'\ americanus (Leidy). The most distinctive feature of /I c^p/Vic/co^o/? as
compared with Bothriodon is the much shorter anterior portion of the maxillae
("snout"). From the canines the lateral margins of the palate curve mediad,
then laterad, without the long, nearly straight portion between the two curves.
Associated with this feature are the much shorter relative lengths of the C-P^
and P^-P- diastemata, although the latter gap is much shorter than the former,
as in Bothriodon. Differences that have been mentioned in the molar structure
are the less bulging mesostyle and the posterad curvature of the lingual part of
the transverse valley. Absence of a diastema between P- and P^ has been
suggested as a distinctive character, but it is also absent in some European
species of Bothriodon. Other characteristics listed as distinctive by Troxell and
Macdonald should be checked against the European material.

Bothriodon advena, n. sp.
Figs. 1-4

ETYMOLOGY. Latin advena, immigrant or foreigner.

TYPES. Holotype, Royal Ontario Museum, Department of Vertebrate Palaeon-

tology (ROM) 2 1744, skull fragment mostly consisting of the maxillae, with left C
to M^ and right P^ and P"^ to M\ Paratype, rom 21745, incomplete mandible
with left Pi toP4, M.and M3, and right P2toP4, M2and M3, and alveoli for three
incisors and a canine on each side and for right P,; probably from same
individual as rom 21744; Saskatchewan Museum of Natural History (smnh)
P 1063. 1 , incomplete left maxilla with P' to M"* and trace of alveolus for canine.

PROVENIENCE. Cyprcss Hills Formation, Lower Oligocene. Calf Creek valley,
sees. 7 and 8, tp. 8, rge. 22, W. 3rd merid., Saskatchewan.

SPECIFIC DIAGNOSIS

Upper canines moderately large for the genus. P^ present; P- simple, without
posterior cusp; P*^ without lingual cingulum; transverse valley of upper molars
terminating labially as a pointed end on M' and M-, as a rounded U-shape on
M^; posterior cingulum near midwidth on M\ In lower dentition, P3 and P4 are
widest posteriorly, the latter tooth having an incipient talonid; M3 with
hypoconulid almost as high as hypoconid.

DESCRIPTION

The holotype of the species (rom 21744) consists almost entirely of the two
maxillae. Anteriorly there may be a small fragment of the left premaxilla, and
posteriorly the anterior portion of the palatines extends in the median area as
far forward as the anterior margin of M\ The dorsal side of the specimen is
shattered and encrusted, but further preparation might lead to collapse. The
roof of the nares is visible posteriorly, as is the anterior floor of the orbital
cavities. The anterior portion of the maxillae is bent downward between P' and
P-, but this is evidently a post-mortem distortion. Seen in ventral view the most
striking feature is the contrast between the narrow, elongate anterior portion of
the maxillae and the abrupt lateral expansion from P"* posterad. This is em-
phasized by the small and well-spaced teeth from incisors to P^ and the
relatively massive and close-spaced teeth from P^ to M\ The spoon-like
expansion of the premaxillae and anterior part of the maxillae, characteristic of
the genus, is obscured in this specimen by breakage and distortion.

None of the six incisors is represented, not even by portions of the alveoli.
The left canine is prominent but not tusk-like. It emerges from its alveolus at a
low angle, then curves forward, outward, and downward. The crown makes up
about half of the tooth presently exposed. It is pointed, recurved, and laterally
compressed, with no serrations on either edge.

There is a long diastema between the canine and the first premolar. The latter
tooth is small, with a low, compressed, trianguloid crown, from the apex of
which a blunt, nonserrate edge extends fore and aft. The two roots are swollen,
and divergent dorsally.

Between P' and P- there is a moderately long diastema, less than half the
length of that between C and P'. P- is like P' but larger, and with a less
compressed crown. The apex is slightly in front of midlength, and a strong but
worn ridge extends from it posterodorsad to the posterior margin. Anterior to
the apex there are two low ridges, diverging anterodorsad. External and inter-
nal cingula are present, weak anteriorly, strong and denticulate posteriorly.

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P^ is a much larger tooth , trianguloid in crown view, the posterolabial portion
bulging labiad in conformity with the changing orientation of the maxillary
margin. The apex of the tooth is slightly in front of midlength. From this a ridge
extends anterodorsad to the anterolingual angle of the crown. There is an
elongate wear facet on the anterior slope of the crown but this is in the midline
of the tooth and does not obliterate any of the anterolingual ridge. On the
posterior side of the apex there is a strong ridge extending posterolabiad to join
with a distinct cusp (''tritocone'') and continue to the posterolabial angle of the
crown. The posterior face of the crown is a broad, flat wear facet, which has
been formed by the destruction of most of the posterior cingulum, but leaving
part of the enamel surface. There is a weak, striate, external cingulum, and a
denticulate internal cingulum.

P"* is a very different tooth, ovoid in outline, distinctly wider than long, and
resembling the anterior half of the first molar. The crown consists of two cusps,
an outer, principal cusp (paracone analogue) with a V-shaped crest, and a
somewhat smaller and conoid inner cusp (''deuterocone''). The labial margin
of the crown is slightly sinuous, with distinct anterior and posterior angles, but
the lingual margin is rounded. The cingulum is vestigial on the labial margin,
weak anteriorly and posteriorly, and absent from the lingual margin.

M' was evidently a slightly smaller version of M-, but it has been heavily
worn. The protocone-paracone-metacone area has been reduced to a large,
horizontal facet, while the hypocone, metacone, and posterior margin have
been entirely removed, leaving a slightly concave facet that slopes posterad.
The only diagnostic feature preserved is the labial end of the transverse valley,
which is a pointed re-entrant on the lingual side of the mesostyle.

M- is somewhat larger than M^ It is rectanguloid in crown view, except for
the metastyle angle, which protrudes posterad. Wear has reduced the pro-
tocone and protoconule to a large, triangular facet. The hypocone, although
worn, still retains its V-shaped crest. Paracone and metacone also have their
V-shaped crests partially preserved. The mesostyle, although worn, preserves
the pointed end of the transverse valley. The anterior and posterior cingula
have been mostly removed by wear.

M^ is slightly larger than M-, and is only moderately worn. The pyramidoid
protocone is still pointed, but the protonule shows some wear. The postero-
lingual slope of the protocone is radially ribbed. The V-shaped crest of the
hypocone is worn anteriorly, intact posteriorly. The V-shaped crests of the
paracone and metacone are variously worn, the posterior arm in each case
being more truncated than the anterior. The transverse valley has numerous
cross-crenulations; it terminates on the lingual side of the mesostyle as a
broadly rounded notch. The labial and lingual cingula are vestigial. There is a
strong anterior cingulum from the parastyle to a point anterior to the protocone
apex. The posterior cingulum is confined between points posterior to the apices
of the metacone and hypocone, respectively.

The paratype maxilla (smnh P1063. 1) has almost unworn teeth, but unfortu-
nately only the left P' to M^ are present. Compared with the holotype, and
allowing for the excessive wear of the latter, the differences are of minor
degree. The rim of the canine alveolus is not preserved, but about 50 mm of the
C to P' diastema remains.

P^ P^, and P"^ are almost identical in the two specimens. P^, which is unworn
posteriorly on the paratype, shows a strong posterior and lingual cingulum. On
P^ the lingual cusp ("deuterocone") is a little more anteriorly placed than on
the holotype; there is a distinct ridge extending anterolabiad from the apex of
this cusp to the anterior cingulum. The labial margin of the crown is shallowly
concave.

M' is the only worn tooth on the paratype. Protocone and protoconule have
been reduced to a concave facet. The hypocone, paracone, and metacone
retain most of their V-shaped crests. The mesostyle bulges broadly, and the
labial end of the transverse valley is bluntly pointed. There are distinct but
narrow anterior and posterior cingula, and vestiges of an internal cingulum.

M^ is the best-preserved tooth on the paratype. All of the cusps retain a
pointed apex, although the protocone shows incipient wear. The posterior
slope of the protocone has numerous distinct radiating ridges. The transverse
valley ends labially in the mesostyle as a more narrowly pointed notch than on

M^ shows no signs of wear, but the posterior third of the crown has been
fractured and slightly spread. The protoconule is higher than the protocone.
The mesostyle is large, and the labial end of the transverse valley is U-shaped,
rather than rounded or pointed. The anterior cingulum is wide adjacent to
protocone and protoconule; the posterior cingulum is restricted.

The paratype mandible (rom 21745), as noted, could be from the same
individual as the holotype. This is suggested not only by the common proveni-
ence but also by the analogous state of wear of the teeth. The anterior end of the
mandible is narrowly rounded, and the symphysis is long and shallowly
trough-shaped. For the entire length as preserved the two rami are almost
parallel, gradually becoming more massive posteriorly, but showing nothing
like the abrupt divergence of the maxillary margins.

The incisors and canines are represented by their alveoli, which are directed
more anterad than dorsad. P, is represented on the left side by the single root,
the crown having been worn away. The diastema between C and P, is relatively
short. In contrast, the diastema between P, and P2 is almost twice as long. The
dorsal rim of the rami in the P1-P2 diastema is an acute edge.

P2 has a compressed crown, trianguloid in side view, with a single cusp and a
posterolingual denticle. The ridges from the principal cusp have a convex slope
in front, concave behind, giving the tooth a slightly recurved appearance in side
view. The two roots are large and divergent, but not swollen.

P3 is similar to P2 but larger. The rudimentary talonid is worn. There is a
distinct lingual cingulum, which rises up the side of the crown just behind the
apex.

P4 is badly worn, but evidently had a high principal cusp and a distinct
talonid. In crown view the outline tapers obliquely in front of the principal cusp
but is broadly rounded behind. There is a strong lingual cingulum.

M, is missing on both sides. Judging from the extreme wear of M2, the MM,
must have been reduced to their roots during life, and may have been dis-
carded. M2 is very badly worn, the protoconid being completely removed, and
the metacone reduced to a remnant. The talonid on the left M2 is as worn as the
trigonid, but on the right M2 there is a large remnant of the hypoconid.

M3 is moderately worn, there being curious discrepancies between this tooth
on the right ramus and that on the left. Thus the metaconid is high and pointed
on the right, truncated on the left. In contrast, the entoconid is less worn on the
left than on the right. Protoconid and hypoconid have oblique V-shaped crests,
whereas metaconid and entoconid are conoid. The hypoconulid lobe is well
developed, curving posterolabiad. It is only slightly worn, the posterior trunca-
tion on the right M3 being a post-mortem break, not a wear facet.

DIMENSIONS

Vertical

Holotype, rom 21744

Left canine 15.2 mm

Diastema, C to P'

Maxillae between dentigerous margins at PP'

Left P' at base of crown

Diastema, P' to P-

Left P-, at base of crown

Left P^

Left P'*

LeftM'

Left M-

Left M^

Maxillae and palatines between dentigerous mar-
gins at MM^

t-post. Tf

•ansverse

10.9mm

7.9 mm

67.7

36.0

8.5

4.8

21.0

14.0

7.8

17.8

17.3

20.5

21.4

24.9

28.3

31.0

30.8

31.4

113

Paratype, smnh P1063.1

Diastema, left C to P'. . .

LeftP'

Diastema, left P' to P- .
Left P^ at base of crown
LeftP^

Left P"*
LeftM'

Left M-
LeftM^

+ 53
8.7

±19
16.2
18.6
15.6
22.3
29.3

±30

5.1

8.5
17.6
20.1
24.3
30.9
33.3

Paratype, rom 2 1745

Mandibular symphysis 94. 1

Diastema, left C and Pi 25.3

Left Pi , as preserved 8.5

Diastema, left Pi to P2 46.5

Right P2, at base of crown 12.1

Right P3, at base of crown 19.2

Right P4 19.6

Right M2 22.5

Right M3 38.0

5.5

6.1

8.9

12.8

18.0

19.4

DISCUSSION

The anthracothere dentition usually shows much difference in the degree of
wear between teeth of the same series, but in the holotype maxillae and the
paratype mandible of this species the condition reaches an extreme, not
equalled by the paratype maxilla. This suggests either an unusually harsh diet
or an exaggerated time interval between the eruption of successive teeth. Thus
the first molar, both above and below, appears to have had the crown almost
completely obliterated before the last molar and the fourth premolar were
entirely functional.

The nature of the wear facets is also noteworthy. Most of these facets on the
upper cheek teeth have a nearly horizontal transverse axis with a posterad or
anterad slope. This suggests that most of the jaw motion in chewing was
transverse. We can visualize the animal stripping, rather than cropping, vegeta-
tion with its well-spaced but weak anterior teeth, then working it back to the
wide cheek region for comminution by side-to-side motion of the lower denti-
tion against the upper. Such movement would have to be wide because of the
much greater lateral distance between the tooth rows on the maxillae and those
on the mandible. In this motion the anterior portion of the mandible would have
to swing widely on the pivot of the glenoid cavities, but as the anterior teeth
were not interlocking, this motion was evidently no problem. The general
effect would be an exaggerated "chewing-the-cud'' motion comparable to that
of ruminants.

The well-preserved right M^ referred by Lambe (1908, p. 24) to Ancodus
{Hyopotamus) brachyrhynchus Osborn and Wortman is of about the same size
as that tooth in Bothriodon advena. There are, however, a number of differ-
ences. The V-shaped crests on paracone and metacone are less acutely angu-
late on Lambe's specimen, and there is a posterolabial crest from the pro-
tocone. The transverse valley is more shallow, and its labial half is deflected a
little posterad, instead of being directed strictly labiad. In these features the
tooth closely resembles a left M^ (rom 973) identified as Elomeryx annatus
(Marsh), from the Brule Formation of South Dakota. It was obtained in ex-
change from the American Museum of Natural History. As Ancodus
brachyrhynchus is now regarded as a synonym of Elomeryx armatus (Mac-
donald, 1956), Lambe's identification was very good and cannot be improved
upon in spite of the greater geological age of the Cypress Hills specimen.

Lambe also referred, with question, to Ancodus brachyrhynchus a left P"^
that is very unlike the P"^ of Bothriodon advena. In addition to being smaller,
Lambe's specimen has a broad, shallowly concave shelf projecting posterolin-
guad, in place of a simple cingulum. Lambe also described two lower incisors
and a lower canine, but as these teeth are missing from the type material of ^.
advena, no comparisons can be made at present.

Comparison of the dentition oi Bothriodon advena with that of other species
definitely belonging to that genus shows only minor differences. The other
North American species, B. rostratus (Scott), differs most conspicuously in the
absence of P'. Macdonald (1956, p. 622) suggested that this might be only an
individual variation, but Scott (1940, p. 465) noted that this tooth was com-
pletely unrepresented in both the specimens that he studied. The handsome

skull of B. rostratus in the Princeton University Museum that was figured by
Scott (op.cit., pi. 46) has a spoon-like outline of the anterior palate, a feature
seemingly less developed in B. aclvcna. Another difference is the presence of a
complete internal cingulum on P^ in B. rostratus. In that species the transverse
valleys of all of the upper molars, not just M\ have a rounded labial end.

Turning to the European species of Bothriodon, we find that the nomencla-
ture and the specific identities are as confused as those for the genera. The first
species to be recognized was "'Anthracotherium'^ veUiunus. This is usually
credited to Cuvier, but he (1835) referred to it only in the vernacular, ''An-
thracotheriums du Puy en Velay'\ Apparently von Meyer ( 1832) was the first to
use a formal binomial for the species, translating Cuvier's name into An-
thrcicotherium veUiuniim. Following this, various authors such as Aymard
( 1846), Pomel ( 1847), and Owen (1848) added species, until Filhol (1882), using
PomeFs generic name revised to Ancodiis, recognized four species: Ancodus
velauiuis Pomel [sic], A. leptorhynchus (Aymard), A. hovinus (Owen), and
A. porcinus Pomel. In 1885 Lydekker recognized a somewhat different set of
species: Hyopotamiis velauniis (Cuvier) (including H. vectianus Owen), H.
boviniis Owen, //. porcinus (Gervais), H. americanus (Leidy), H. picteti
Lydekker, and H. giganteus Lydekker. He followed Filhol in assigning An-
codus aymardi Pomel to A. leptorhynchus, and in turn synonymized A. lep-
torhynchus with Hyopotcunus hovinus.

Without access to European collections and to all of the literature I shall not
attempt a critical review of the species of Bothriodon, but for comparison with
the Cypress Hills species I shall recognize four species as distinct: B. velaunus
(von Meyer), B. leptorhynchus Aymard, B. hovinus (Owen), B. vectianus
(Owen). B. velaunus, on the basis of the skull described by Filhol, has the
greatest resemblance to B. advena. Thus the canine appears to be moderately
large, and close to the P. The diastema between C and P' is a little more than
three times in length that between P' and P'. P^ is trianguloid, and P'* has a
distinct lingual cusp. Differences to be noted are the absence of a posterolabial
projection of P\ the relatively narrower P"^ (in B. advena this tooth is almost as
wide as M'), and the broadly rounded or inflated labial ends of the transverse
valley of the molars. The dental dimensions of ^. velaunus are about three-
quarters those of ^. advena.

The skull described by Filhol as Ancodus leptorhynchus has dimensions
similar to those of Bothriodon advena but there are striking differences. The
canine is large and recurved in suid fashion, and is well separated from V. The
snout is extremely elongate, the distance from C to P-^ exceeding the length of
P^ to M\ The diastema between P' and P' is relatively long, being about -/s that
of the C-P' diastema compared to ^/-j in B. advena. In B. leptorhynchus the P^ is
ovoid rather than trianguloid, and P'* is about as long as wide, with rudimentary
lingual cusp but a distinct internal cingulum. The transverse valley of the
molars is expanded at the labial end, especially on M^.

B. aymardi was regarded by Filhol, with reservations, as the female of ^.
leptorhynchus. In view of other differences in addition to smaller size and
reduced canine, it seems better for purposes of comparison with B. advena to
regard the two Ronzon species as distinct. In size, according to Filhol, B.
aymard is about 0.6 that of ^. leptorhynchus and about 0.7 that of ^. velaunus.

On the basis of Filhol's plate 16, the dental dimensions ofB. aymardi are about
two-thirds those ofB. advena. On B. aymardi there is a short diastema between
P^ and P^, and the latter tooth is rounded-trianguloid, with no posterolabial
projection. P'* is short and wide, as in B. advena, but the lingual cusp is less
prominent. The labial ends of the transverse valleys of the molars are rounded
but not inflated.

Comparisons with Owen's species from the Isle of Wight are difficult, as the
specimens on which they are based consist mostly of isolated teeth. Owen
assembled some of these in supposed tooth rows, but as Lydekker pointed out,
the associations are faulty. On the basis of the upper dentition, especially the
dimensions, Lydekker referred ''Hyopotamus'' leptorynchus to "//."
boviniis. As noted, Aymard's name has priority over Owen's. However,
Bothhodon boviniis has a wide P^ with large lingual cusp, as in ^. advena, and
the transverse valleys on the upper molars are broadly rounded but not inflated
at the labial end. I think that Bothriodon leptorhynchiis and B. boviniis should
be retained as distinct species until the discovery of associated tooth rows of
the EngUsh species, when the question of their validity might be reconsidered.

In summary, Bothhodon advena, 2i\ong with B. rostratiis (Scott), is a charac-
teristic member of the genus Bothriodon, as distinct from Aepinacodon
Troxell. The new species differs from the European members of Bothriodon in
various minor details. Closest resemblances are to B. velaiinus, to which it
would probably be referred if found in Europe. It is generally agreed that the
anthracotheres originated in Eurasia and made their way into North America in
Oligocene time. As the oldest-known American species geologically, and the
closest geographically to the Bering connection, Bothriodon advena may be
regarded as a relatively unmodified member of the immigrant stock, hence the
choice of specific name.

Acknowledgements

Loan of anthracothere specimens in the vertebrate palaeontology collection of
the National Museum of Natural Sciences, Ottawa, was arranged by Dr. D. A.
Russell . The left maxilla described above as the paratype oi Bothriodon advena
was lent by the Saskatchewan Museum of Natural History, courtesy of Dr.
John E. Storer, Assistant Director. Loan of the rare volume cited under Filhol
(1882) was arranged by Dr. Robert E. Carroll from the McGill University
Library. Specimens and facilities in the Department of Vertebrate Palaeontol-
ogy, Royal Ontario Museum, were provided by Dr. A. G. Edmund, Curator.

Literature Cited

AYMARD, AUGUSTE

1846 Essai monographique sur un nouveau genre de mammifere fossile trouve dans la
Haute-Loire, et nomme Entclodon. Annales de la Societe d'agriculture, sciences, arts
et commerce du Piiy. 12 (1842-46): 227-267, 1 pi.

CUVIER, GEORGES

1835 Recherches sur les ossemens fossiles, ou Ton retablit les caracteres de plusieurs
animaux dont les revolutions du globe ont detruit les especes. Paris, Edmond
d'Ocagne; 4th ed. , 5(3): 480, 48 1 .

FILHOL, HENRI

1882 Etude des mammiferes fossiles de Ronzon (Haut-Loire). Annales des sciences
geologiques, Paris, 12(3): 1-271, 26 pis.

LAMBE, L. M.

1905 Vertebrate palaeontology. Geological Survey of Canada, Summary report of the opera-
tions of the Geological Survey for the year 1904: 362-37 1 .

1908 The Vertebrata of the Oligocene of the Cypress Hills, Saskatchewan. Geological
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LYDEKKER. RICHARD

1885 Catalogue of the fossil Mammalia in the British Museum (Natural History) Part II.
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pp., 38 figs.

MACDONALD. J. R.

1956 The North American anthracotheres. Journal of Paleontology, 30(3): 615-645, 16 figs.

MATTHEW, W. D.

1909 Observations on the genus Ancodus. Bulletin of the American Museum of Natural
History, 26(1): 1-7.

MEYER, H. VON

1832 Palaeologica, zur Geschichte der Erde und ihrer Geschopfe. Frankfurt a.M., 560 pp.

OWEN, RICHARD

1848 Descriptions of teeth and portions of jaws of two extinct anthracotherioid quadrupeds
(Hyopotamiis vectianns and Hyop. hoviniis) discovered by the Marchioness of Hast-
ings in the Eocene deposits on the N.W. coast of the Isle of Wight: with an attempt to
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Quarterly Journal of the Geological Society of London, 4(1): 103- 141, 2 pis.

POMEL, AUGUSTE

1847 Note critique sur les caracteres et les limites du genre PaUwothcntiin. Archives des
sciences physiques et naturelles, Geneva, 5: 200-207.

SCOT I , W. B.

1940 Artiodactyla. Part IV in Scott, W. B., and G. L. Jepsen, The mammalian fauna of the
White River Oligocene. Transactions of the American Philosophical Society, 28:
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IROXLLL, h. L.

1921 The American bothriodonts. American Journal of Science, 201(21): 325-339, 7 figs.

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