The “condylarths” (archaic Ungulata, Mammalia) from the early Palaeocene of Tiupampa

104 Pages·2000·0.87 MB·English

The “condylarths” (archaic Ungulata, Mammalia)
from the early Palaeocene of Tiupampa (Bolivia):
implications on the origin of the South American
ungulates
ChristiandeMUIZON
Laboratoire de Paléontologie, UMR 8569 du CNRS, Muséum national d’Histoire naturelle,
8rue de Buffon, F-75231 Paris cedex 05 (France)
[email protected]
RichardL.CIFELLI
Oklahoma Museum of Natural History and Department of Zoology, University of Oklahoma,
1335 Asp Ave., Norman, Oklahoma 73019 (USA)
[email protected]
MuizonC.de & CifelliR.L. 2000.—The “condylarths” (archaic Ungulata, Mammalia) from
the early Palaeocene of Tiupampa (Bolivia): implications on the origin of the South
American ungulates. Geodiversitas22 (1) : 47-150.
ABSTRACT
The oldest known “condylarth” fauna of the Tertiary of South America
comes from basal Palaeocene strata of the Santa Lucía Formation at
Tiupampa (Bolivia). It includes five genera and seven species: Molinodus
suarezi, Tiuclaenusminutus,T.cotasin.sp., T.robustusn.sp., Pucanodus gag-
nieri, Andinodus boliviensis, and Simoclaenus sylvaticus, n. gen., n. sp. This
work presents a thorough revision of all the fossils previously described, which
are interpreted in the light of recently discovered specimens including materi-
als belonging to three new taxa. The sample contains 33 jaws and 43 isolated
teeth. The Tiupampa “condylarths” are included in the Kollpaniinae
Marshall, Case & Woodburne, 1990 (=Molinodinae Bonaparte, Van Valen
& Kramartz, 1993), a subfamily of the Mioclaenidae (Kollpania tiupampina
Marshall & Muizon, 1988, the type species of the type genus of the
Kollpaniidae Marshall, Case & Woodburne, 1990 is regarded as a junior syn-
onym of Tiuclaenus minutus Muizon & Marshall, 1987). Some of the taxa
(e.g., Molinodussuarezi, Tiuclaenuscotasi) are well represented and the cheek
dentition of the former is almost completely known. However, other genera
such asAndinodusandSimoclaenusare still poorly known (a few lower teeth
only in the case of Andinodus). Because of their scant representation, their
position within the Kollpaniinae still has to be confirmed by the discovery of
new specimens, especially upper molars of Andinodus. The Tiupampa
“condylarths” are clearly related to the North American Mioclaenidae,
although it is not possible to securely relate them to a specific genus. They
share with the North American taxa the following derived characters when
compared to Protungulatum: bulbous cusps, the apices of which are approxi-
mated in occlusal view; protocone enlarged; stylar shelf greatly reduced or
GEODIVERSITAS • 2000 • 22 (1) 47
MuizonC.de & CifelliR.L.
lost; styles reduced and tending to be aligned with para- and metacristae;
paraconid appressed against metaconid; entoconid and hypoconulid connate
to fused, and forming an obliquely oriented posterolingual crest. The major
characteristics of the Kollpaniinae are: metaconid well posterior to proto-
conid, strongly inflated, and invading the talonid basin posteriorly; loss of the
entocristid; hypoconid extremely inflated, occupying at least the medial half
of the talonid (generally more); talonid basin reduced to an obliquely oriented
groove that is widely opened lingually; posterior slope of the hypoconulid of
m3 less convex than in the other mioclaenids. The Kollpaniinae (Tiupampa
“condylarths” and Escribania) are also regarded as closely related to the
Didolodontidae and Litopterna (especially the Protolipternidae). The key
synapomorphy of the three groups is the morphology and development of the
paracristid, which is narrower than half the width of the trigonid, deeply
arched posteriorly, projected anteriorly, and attaching on the anterior to
anterolingual side of the proto- and paraconids. Study of the Tiupampa
“condylarths” confirms that the South American Didolodontidae and
Litopterna have their origins in North American Mioclaenidae. A parsimony
analysis establishes the monophyly of the clade including the North American
Mioclaenidae, the Kollpaniinae (South American Mioclaenidae), the
KEY WORDS Didolodontidae, and the Litopterna. This clade is formally designated as a
“Condylarths”, new order of mammals, the Panameriungulata. Because no close relationships
Didolodontidae,
based on dental characters were found with the other groups of South
Litopterna,
Panameriungulata, American ungulates (or so-called ungulates) — Astrapotheria, Pyrotheria,
early Palaeocene, Xenungulata, Notoungulata—, it reinforces the unlikelihood of a single ori-
Bolivia,
gin of the South American ungulates and therefore brings into question the
taxonomy,
phylogeny. monophyly of the Meridiungulata.
RÉSUMÉ
Les «condylarthres» (ongulés archaïques,Mammalia) du Paléocène inférieur de
Tiupampa (Bolivie): implications sur l’origine des ongulés sud-américains.
La plus ancienne faune de «condylarthres» du Tertiaire sud-américain pro-
vient du Paléocène basal de la Formation Santa Lucía à Tiupampa (Bolivie).
Elle comprend cinq genres et sept espèces : Molinodus suarezi, Tiuclaenus
(T.minutus,T.cotasin.sp., T.robustusn.sp.), Pucanodus gagnieri, Andinodus
boliviensis et Simoclaenus sylvaticus, n. gen., n. sp. Ce travail présente une
revue de tous les fossiles précédemment décrits, lesquels sont interprétés à la
lumière de nombreux spécimens récemment découverts, incluant trois nou-
veaux taxons. L’échantillon contient 33 mâchoires et 43 dents isolées. Les
«condylarthres » de Tiupampa sont inclus dans les Kollpaniinae Marshall
Case & Woodburne, 1990 (= Molinodinae Bonaparte, Van Valen &
Kramartz, 1993), une sous-famille des Mioclaenidae (Kollpania tiupampina
Marshall & Muizon, 1988, l’espèce-type de la famille des Kollpaniidae
Marshall, Case & Woodburne, 1990, est considérée comme un synonyme
plus récent de Tiuclaenus minutus Muizon & Marshall, 1987). Certain des
taxons (Molinodus suarezi,Tiuclaenus cotasi) sont bien représentés et les dents
jugales de ces derniers sont presque toutes connues. Cependant, certains
genres comme Andinodus et Simoclaenus, sont encore mal connus (par
quelques dents inférieures seulement pour Andinodus) et, en raison de la pau-
vreté de cet échantillon, leur position au sein des Kollpaniinae devra être
confirmée par la découverte de nouveaux spécimens, en particulier de dents
supérieures d’Andinodus. Les « condylarthres » de Tiupampa sont, de toute
48 GEODIVERSITAS • 2000 • 22 (1)
“Condylarths” from the early Palaeocene of Bolivia
évidence, apparentés aux Mioclaenidae nord-américains, bien qu’il ne soit pas
possible de les relier avec certitude à un genre précis. Ils partagent avec les
formes nord-américaines les caractères dérivés suivants, par comparaison avec
Protungulatum : cuspides bulbeuses dont les apex sont rapprochés en vue
occlusale ; grand protocone ; plate-forme stylaire très réduite ou perdue ;
styles réduits et tendant à s’aligner avec les para- et metacristas ; paraconide
plaqué contre le métaconide ; entoconide et hypoconulide accolés, voire
fusionnés, et formant une crête postéro-linguale oblique. Les principales
caractéristiques des Kollpaniinae sont: très gros métaconide renflé, très posté-
rieur au protoconide et envahissant partiellement le bassin du talonide posté-
rieurement ; perte de l’entocristide ; hypoconide extrêmement gonflé
occupant au moins la moitié labiale du bassin du talonide; bassin du talonide
réduit à un sillon oblique largement ouvert lingualement; flanc postérieur de
l’hypoconulide de m3 moins gonflé et moins convexe que chez les autre
Mioclaenidae. Les Kollpaniinae (« condylarthres » de Tiupampa et
Escribania) sont également considérés comme ayant des relations étroites avec
les Didolodontidae et les Litopterna (particulièrement les Protolipternidae).
La synapomorphie majeure qui réunit les trois groupes réside dans la morpho-
logie et le développement de la paracristide. Celle-ci est plus étroite que la
moitié de la largeur du trigonide, profondément arquée postérieurement, for-
tement saillante antérieurement et prend attache sur les bords antérieurs à
antéro-internes des para- et protoconides. L’étude des «condylarthres» de
Tiupampa confirme donc l’origine septentrionale, au sein des Mioclaenidae,
des Didolodontidae et des Litopterna d’Amérique du Sud. Une analyse de
parcimonie conduit à la monophylie probable du clade incluant les
Mioclaenidae d’Amérique du Nord, les Kollpaniinae (Mioclaenidae
d’Amérique du Sud), les Didolodontidae et les Litopterna. Le clade est for-
MOTS CLÉS mellement désigné comme un nouvel ordre de mammifères, les
«Condylarthres», Panameriungulata. Étant donné qu’aucune relation étroite fondée sur des
Didolodontidae,
caractères dentaires n’a pu être mise en évidence avec les autres groupes
Litopterna,
Panameriungulata, d’ongulés (ou considérés comme tels) sud-américains, — Astrapotheria,
Paléocène inférieur, Pyrotheria, Xenungulata, Notoungulata —, cette étude donne du poids à
Bolivie,
l’invraisemblance d’une origine unique des ongulés sud-américains et met en
taxonomie,
phylogénie. question la monophylie des Meridiungulata.
INTRODUCTION in situ, having their ancestry among North
American “condylarths” that migrated to South
The origin of the unique Tertiary ungulate fauna America sometime in the Late Cretaceous or
of South America has long captivated the atten- early Tertiary (Simpson 1978). Hence, the less
tion of palaeontologists and evolutionary biolo- derived of the South American ungulates, which
gists (e.g., Patterson & Pascual 1972; Simpson are included among the “condylarths” (see p. 68
1980). Such groups as notoungulates, for understanding of the term Condylarthra vs
pyrotheres, astrapotheres, trigonostylopoids, “Condylarthra” or “condylarths”), are pivotal to
litopterns, and xenungulates are unknown on understanding the origin of a substantial part of
other continents and the problem of their origin South America’s endemic mammalian fauna
remains unresolved (McKenna 1981; Cifelli (Simpson 1948).
1983a; 1985; Bergqvist 1996). It is generally South American “condylarths” were first recorded
believed that some or all of these groups evolved from what would later become known as the
GEODIVERSITAS • 2000 • 22 (1) 49
MuizonC.de & CifelliR.L.
Casamayoran land-mammal age, presumed to be no more than advanced ‘condylarths’ surviving
early Eocene in age (Marshall et al. 1983), in in South America long after this general structur-
some of the initial descriptions of the fauna (e.g., al grade had been replaced elsewhere…”
Ameghino 1897, 1901, 1902, 1904). In his great (Simpson 1948: 97.) Hence, although Itaboraí’s
summary treatise of 1906, Ameghino referred “condylarths” possess a rather generalized denti-
then known taxa to various Holarctic families tion (as do those of the Casamayoran), they appear
(see reviews by Simpson 1948; Cifelli 1983a). to have been already specialized along lines seen
Later workers (e.g., Scott 1913) referred South in members of later South American faunas.
America’s Eocene “condylarths” to the endemic Cifelli (1983a: 38) suggested that Mioclaeninae
family Didolodontidae. It has long been recog- were best suited among North American
nized that these taxa are rather similar to certain “Condylarthra” as structural antecedents for the
North American forms, particularly among the South American Didolodontidae, using argu-
somewhat specialized family Phenacodontidae. ments based on morphotype reconstruction and
However, at the same time it is clear that the development of a hypothesized ancestral
Casamayoran and later didolodonts are too late morphology for South American taxa. Evidently,
in time to present much in the way of direct, Itaboraí’s “condylarths” — important though
compelling evidence that would speak to their they are — significantly postdate faunal
ancestry among North American “Condylarthra” exchange between the two American subconti-
(Simpson 1948). nents.
An important new venue on the problem A few years later, the discovery of substantially
appeared in the 1950s, with the recovery of a older South American “condylarths”, in the early
vastly better represented “condylarth” fauna from Palaeocene of Tiupampa (Bolivia), offered some
fissure fill deposits at the Itaboraí locality in support for Cifelli’s assumption. Molinodus
Brazil, which is presumed to be late Palaeocene suarezi and Tiuclaenus minutus (see Muizon &
in age and therefore older than the Casamayoran Marshall 1987 a, b; Marshall & Muizon 1988)
(e.g., Bonaparte et al. 1993; Muizon & Brito were referred to the mioclaenine Hyopsodon-
1993). Paula Couto (1952) initially referred the tidae. Andinodus boliviensis, the third “condy-
“condylarths” of Itaboraí to the Didolodontidae larth” of the fauna, was referred to the dido-
(Ernestokokenia protocenica Paula Couto, 1952; lodontids or phenacodontids (Muizon &
E. parayirunhor Paula Couto, 1952; Lamegoia Marshall 1987b). Another condylarth, Pucanodus
conodonta Paula Couto, 1952) and Hyopso- gagnieri, was described by Muizon & Marshall
dontidae (Asmithwoodwardia scotti Paula Couto, (1991) and was also referred to the Mioclaeninae.
1952). This latter referral is particularly signifi- Van Valen (1988) and Bonaparte et al. (1993)
cant in that it represents the first formal recogni- followed this interpretation and accepted the
tion by a modern worker of a close tie between a mioclaenine affinities of Molinodus, Tiuclaenus,
South American “condylarth” and an otherwise and Pucanodus, although they gave the subfamily
Holarctic family. However, Paula Couto later a family rank (an arrangement which we follow
(1978) recanted his view, opting for the more for reasons given below), therefore assigning the
conservative placement of Asmithwoodwardia three taxa to the Mioclaenidae. They were fol-
Paula Couto, 1952 in the Didolodontidae. More lowed in this respect by Muizon (1998: 24).
recent revision of the Itaboraí fauna (Cifelli Since their first description, the “condylarths” of
1983a) upheld the distinctiveness of South Tiupampa have been discussed several times,
America’s native “condylarth” family. Most taxa based on material originally described (Marshall
were referred to the Didolodontidae, although & Muizon 1988; Van Valen 1988; Muizon &
Miguelsoria parayirunhor (= Ernestokokenia Marshall 1991; Muizon 1992; Muizon & Brito
parayirunhor) and, tentatively, A. scotti were 1993; Bonaparte et al. 1993). Numerous new
transferred to the Litopterna. This view reflects specimens are now available, considerably aug-
the long-standing belief in a relationship menting knowledge of described species, as well
between the two: “The Litopterna are, in effect, as providing the basis for recognition of several
50 GEODIVERSITAS • 2000 • 22 (1)
“Condylarths” from the early Palaeocene of Bolivia
additional new taxa, including two new species of 1. “Zhelestidae” (Archibald 1998; Nessov et al.
Tiuclaenus and one new genus of Mioclaenidae 1998)
(Muizon 1998: 24). This new material also pro- The “Zhelestidae” are the most primitive known
vides more substantial basis for the attribution of Ungulatomorpha and represent a useful basis for
some of the previously described specimens and a evaluating the polarity of character states. They
clearer understanding of the relationships of the are essentially from central Asia (but also present
Tiupampa “condylarths” to the North and South in North America and western Europe) and were
American taxa. The new fossils, therefore, shed recently revised by Nessov et al.(1998).
light on the phylogenetic origin of the South
American “condylarths”. Aspanlestes aptap Nessov, 1985: CCMGE
Our present intents are to provide a general study 6/12176, 1/12455 (Bissetky Formation, Uzbe-
of Tiupampa’s “condylarths”, including a more kistan; Turonian-Coniacian).
detailed description of the previously described
taxa on the basis of both published and new Parazhelestes minorNessov et al., 1998, P.robustus
material, and to describe the new taxa mentioned Nessov, 1993: CCMGE 11/12353, 11/12953
above. We shall also present a character analysis (holotype of P. minor), 70/12455 (holotype of
and a discussion including most of better known P. robustus), 20/12953 (Bissetky Formation,
South American taxa and the relevant North Uzbekistan; Turonian-Coniacian).
American genera.
The age of the Tiupampa beds has been exten- Eoungulatum kudukensis Nessov et al., 1998,
sively discussed in the recent literature (Muizon E. cf. kudukensis: CCMGE 2/12455 (holotype),
et al. 1984; Van Valen 1988; Ortiz Jaureguizar 35/12176, 16/12953, 17/12953 (Bissetky
& Pascual 1989; Marshall 1989; Gayet et al. Formation, Uzbekistan; Turonian-Coniacian).
1992; Muizon & Brito 1993; Bonaparte et al.
1993; Marshall et al. 1995; Bonaparte & 2. Arctocyonidae (Van Valen 1978; Cifelli
Morales 1997; Marshall et al. 1997; Muizon 1983a)
1998), and needs no further consideration here. Protungulatum donnaeSloan & Van Valen, 1965:
In agreement with Muizon & Brito (1993), SPSM 62-2028 (holotype), UCMP 100824,
Bonaparte et al. (1993), Bonaparte & Morales 112110; UMVP 1563, 1567; UM 5206 (also
(1997), and Muizon (1998) we regard the fos- figures in Kielan-Jaworowska et al.1979) (Bug
siliferous horizon at Tiupampa (Santa Lucía Creek Anthills, Montana; earliest Palaeocene).
Formation) to be of earliest Palaeocene age, and Protungulatumis a primitive taxon from the early
older than the mammalian fauna of Punta Palaeocene of North America (see Archibald &
Peligro (Bonaparte et al., 1993) from Patagonia. Lofgren 1990, Eberle & Lillegraven 1998). It was
The Tiupampa “condylarths” are, therefore, the classified within the arctocyonids by Van Valen
oldest known on the South American conti- (1978) but Prothero et al.(1988) excluded it from
nent. this family and regarded this genus as part of a tri-
chotomy with peryptichiids and hyopsodontids.
For Archibald (1998), Protungulatumis part of a
MATERIALS AND METHODS trichotomy with the arctocyonids on the one hand
and all the other “condylarths” (including
BASISFORTAXONOMICCOMPARISONS cetaceans and paenungulates, on the other.
We studied available fossils and casts of numer- Prothero et al.(1988), McKenna & Bell (1997),
ous specimens, as well as published descriptions and Archibald (1998) regard Protungulatumas an
and illustrations. Because systematic and material incertae sedis ungulate although Eberle &
bases for “condylarth” comparisons are often Lillegraven (1998) included it in the oxyclaenines
unclear, we list below the taxonomic concept and arctocyonids. Regardless of its higher taxonomic
principal specimens (and their origin) that are placement, because of its age and its primitive
most central to this study. morphology, this genus is regarded as important in
GEODIVERSITAS • 2000 • 22 (1) 51
MuizonC.de & CifelliR.L.
the analysis of the relationships of the Included species: the type species only.
Kollpaniinae (see below for definition). Distribution: Puercan (early Palaeocene), New
Mexico and Wyoming.
Oxyprimus galadrielaeVan Valen, 1978: YPM(PU) Etymology: for Leigh Van Valen, in recognition
16217, 16703, 16712, 16863, 16866 (holotype), of his substantial contributions to knowledge of
17297, 21109, 21122. The position of the taxon early ungulates, particularly those of the North
has not reached a consensus. Van Valen (1978) in- and South American Palaeocene.
cluded it in the oxyclaenine Arctocyonidae, Diagnosis: small mioclaenid differing from the
McKenna & Bell (1997) in the separate family otherwise similar Promioclaenusin having the fol-
Oxyclaenidae, and Archibald (1998) in the lowing primitive characters: p4 less inflated; P3-4
Hyopsodontidae. However, because the genus with smaller, anteroposteriorly shorter protocone;
Oxyprimushas been regarded by Luo (1991) as pos- P4 with less distinct pre- and postcingula; upper
sessing more primitive character states than molars with broader labial cingulum (remnant of
Protungulatumand Mimatuta, we regard this taxon stylar shelf); pre- and postcingulum smaller,
as a useful comparative element for basal “condy- postcingulum not attaching as high on the proto-
larths”. cone and not extending labially to the styles;
preparaconular and postmetaconular cristae com-
Baioconodon (= Ragnarok) nordicum (Van Valen, plete, extending labially to styles, not captured by
1978): YPM(PU) 14473, 14475, 16694, 16720, the cingula; M3 unreduced.
16854, 21081, 21123 (Mantua lentil, Wyoming; Comments and discussion: Promioclaenuswas es-
earliest Palaeocene). We follow Van Valen (1988) tablished by Trouessart (1904) to include the
and McKenna & Bell (1997), who regard Ragna- Torrejonian species P.acolytusand P.lemuroides,
rok Van Valen, 1978 as a junior synonym of the former earlier referred to Hyopsodus(e.g., Cope
Baioconodon Gazin, 1941. Ragnarok and Baioco- 1882; Matthew 1897) or Mioclaenus(e.g., Osborn
nodonare regarded as distinct genera by Archibald 1902), and the latter to Mioclaenus(see Matthew
(1998) and are both included in the Cetungulata. 1897). A type species was not specified, although
P.acolytuswas listed first and has been regarded as
3.Mioclaenidae (Osborn & Earle, 1895; see Van the type (Gazin 1956). Later workers generally ig-
Valen 1978; Van Valen 1988; Johnston & Fox nored the generic name, placing these species in
1984) Ellipsodon, until Promioclaenuswas resurrected in
A new generic name is proposed for Promioclaenus the 1950s (Gazin 1956; Wilson 1956). Van Valen
wilsoniVan Valen 1978: KU 9446 (holotype) (San (1978) expanded the concept of Promioclaenus,
Juan Basin, New Mexico; Puercan). “Promio- including the aforementioned Torrejonian species,
claenus”wilsonihas been regarded by Van Valen as plus Tiffanian P.pipiringosiand two Puercan
the most primitive species of Promioclaenusand species, P.vanderhoofiand P.wilsoni. The former
the only one known in the Puercan. Other speci- was described by Simpson (1936) under the genus
mens referred to this species have been recently des- Tiznatzinia; its synonymy with Promioclaenushas
cribed from the Western Hanna Basin, Wyoming been debated without apparent consensus (e.g.,
(Eberle & Lillegraven 1998) from the Pu2 and Cifelli 1983a; Archibald 1998; McKenna & Bell
Pu3 zones of the Puercan. 1997; Van Valen 1988).
We regard the differences between “Promio- Van Valen (1978; 1988) considered Promio-
claenus” wilsoni and the other species of Promio- claenus to be the most primitive mioclaenid and
claenus as of generic rather than specific level. regarded “P.” wilsoni as a suitable morphological
Following we propose a diagnosis of the new and temporal ancestor for Torrejonian and later
genus and provide comments and discussion. species of Promioclaenus, and perhaps for other
Mioclaenidae as well. We concur. However, as
Valenian.gen. noted in the character analysis and comparisons
Type species: “Promioclaenus” wilsoni Van Valen, below, we believe “P.” wilsoni to be sufficiently
1978 by original designation. distinct to warrant placement in its own genus,
52 GEODIVERSITAS • 2000 • 22 (1)
“Condylarths” from the early Palaeocene of Bolivia
Valenia – thereby permitting later species of earliest Palaeocene), USNM 23285 (holotype of
Promioclaenus to be recognized as a unit on the B. bombadili; San Juan Basin, New Mexico;
basis of shared, derived characters, while at the Puercan). Bubogonia is a primitive mioclaenid
same time allowing V.wilsonito be recognized (or from the middle Puercan of North America and
not) as their ancestor (indeed, clarifying its ances- regarded by Van Valen (1988) as belonging to the
tral status, if V. wilsoni is ancestral to other mio- same clade as Molinodus.
claenids as Van Valen suggests).
The foregoing diagnosis is based on the type of Escribania chubutensis Bonaparte et al., 1993:
V. wilsoni, KU 9446, which preserves the lower UNPSJB PV 916 (Punta Peligro, Argentina; early
dentition in poor condition, hence we were Palaeocene). Escribania has been referred to the
unable to give consideration to the lower molars Mioclaenidae by Bonaparte et al. (1993) and is
(Van Valen 1988 figured additional specimens of from the early Palaeocene of Punta Peligro
the species, we do not have casts of these avail- (Argentina). It is slightly younger than Molinodus
able). Of the taxa with which V. wilsoni is most and probably has an age close to the North
meaningfully compared, we considered only the American Tiffanian. Raulvaccia from the same
holotype of Tiznatzinia vanderhoofi, a partial locality is known by a single badly broken lower
lower dentition (Simpson 1936); similarly, m1 (not an m2), which is likely to belong to the
P. pipiringosi is confidently known only from same genus as the holotype and single specimen
parts of the lower dentition (Gazin 1956). The of Escribania chubutensis(see below).
originally referred (Torrejonian) species, P. acoly-
tus and P. lemuroides, are both well-known (e.g., 4. Hyopsodontidae (see Van Valen 1978;
Matthew 1937; Simpson 1937). Archibald 1998).
Litomylus dissentaneus Simpson, 1935 (see
Promioclaenus acolytus (Cope, 1882) (see Van Simpson 1937): USNM 9425 (holotype),
Valen 1978): AMNH 15949, BUNM 77-183, AMNH 35920, 35922, 35924, 35927, 35932,
USNM 15294 (San Juan Basin, New Mexico; 35933 (Gidley Quarry, Montana; Torrejonian).
Torrejonian), AMNH 35728, 35778, USNM
9575 (Gidley Quarry, Montana; Torrejonian). Haplaletes disceptatrix Simpson, 1935 (see
Promioclaenus is a primitive mioclaenid known Simpson 1937): USNM 9500 (holotype), 9555,
during most of the Palaeocene of North America. AMNH 35894, 35897, 35898, 35901, 35902
It is very similar in size and morphology to (Gidley Quarry, Montana; Torrejonian).
Molinodus.
5. Periptychidae (see Archibald et al. 1983a, b;
Litaletes disjunctus(Simpson, 1935) (see Simpson Archibald 1996; Archibald 1998)
1937): USNM 9338, AMNH 35871, 35874, Maiorana noctiluca Van Valen, 1978 (see also
35883, 35885, 35889, 35890, 35933 (Gidley Cifelli 1983a): YPM (PU) 14171, 16667 (holo-
Quarry, Montana; Torrejonian). Litaletes is a type), 16715, 21124 (Mantua lentil, Wyoming;
primitive mioclaenid from the Torrejonian of earliest Palaeocene).
North America and was regarded by Cifelli
(1983a) as a possible ancestor for the didolodon- Mimatuta minuial: Van Valen, 1978 YPM (PU)
tids and litopterns. 14172, 14211 (holotype), 21012, 21018 (Mantua
lentil, Wyoming; earliest Palaeocene).
Choeroclaenus turgidunculus(Cope, 1888): AMNH
3291 (holotype), 16402, 16404, 16489, USNM 6.Didolodontidae
15465 (San Juan Basin, New Mexico; Puercan). Paulacoutoia protocenica(Paula Couto, 1952) (see
also Cifelli 1983a): MNRJ 1431V, 1432V,
Bubogonia saskia Johnston & Fox, 1984, B.bom- 1433V, 1434V, 1438V, 1439V, 1441V, 1444V,
badili: (Van Valen 1978) UALVP 15105 (holo- 1448V, 1449V, 1450V, 1454V, 1460V, 1461V,
type of B.saskia; Ravenscrag W-1, Saskatchewan; DNPM 908M (Itaboraí, Brazil; Itaboraian).
GEODIVERSITAS • 2000 • 22 (1) 53
MuizonC.de & CifelliR.L.
Lamegoia conodonta Paula Couto, 1952 (see also (holotype), 4094V, DGM 249M, 296M, 330M,
Cifelli, 1983a): MNRJ 1463V (holotype), AMNH 109556 (Itaboraí, Brazil; Itaboraian).
1464V, 1465V, 1841V, 1842V, AMNH 109552
(Itaboraí, Brazil; Itaboraian). Protolipterna ellipsodontoides Cifelli, 1983a:
DNPM LE 444A (holotype) through 444 I,
Didolodus multicuspis Ameghino, 1897 (see DGM 1308M, 1392D (Itaboraí, Brazil;
Simpson 1948): MACN A-10690 (holotype), Itaboraian)
MACN A-10725, 10730, MLP 59.11.28.14
(Argentina; Casamayoran). In the following description and discussion the
lower teeth will be represented by lower case let-
Ernestokokenia nitida Ameghino, 1901 (see ters and the upper teeth by capital letters. All
Simpson 1948): MACN A-10735 (holotype), measurements are in millimetres and were taken
MACN A-10722, AMNH 28447. MNHN CAS with a Wild MMS 235 digital length-measuring
683 [a relatively unworn upper molar (M2?) system mounted on a stereo microscope. The
described by Simpson (1964: 11), one of the two back background of the photographs has been
upper molars of “No. 6”] and MNHN CAS 681, cropped using Adobe Photoshop 4.0
a mandible fragment with M1-3 (not seen by Dental nomenclature is given in Figure 1.
Simpson). The two latter specimens are referred However, a short comment must be made about
to E.cf.nitida(Argentina, Casamayoran). the use of the terms pre- and postprotocrista,
Ernestokokenia has been regarded as a junior preparaconular and postmetaconular cristae, and
synonym of Asmithwoodwardia by McKenna & para- and metacingulum. The preparaconular
Bell (1997). The great similarity between the and postmetaconular cristae are the parts of the
two genera had been mentioned twice by pre- and postprotocrista labial to the para- and
Simpson in his 1948 monograph. Nevertheless, metaconules respectively. The paracingulum cor-
mainly because of the great size difference responds to the labial part of the preparaconular
between the type species of the genera, he retai- crista and the groove posterior to it, which bor-
ned Ameghino’s generic assignation. Because the ders the paracone anteriorly. The same definition
analysis of this synonymy stands outside the is adaptable to the metacingulum (Van Valen
scope of the present work, we follow Simpson’s 1966; Szalay 1969; Gheerbrant 1992; Nessov et
interpretation, although we admit that McKenna al.1998). Therefore para- and metacingulum are
& Bell may have been correct. In the following “geographically” related to the para- and meta-
comparisons and discussions reference to cone and correspond to a functional structure of
Ernestokokenia will concern E. nitida and more the preparaconular and postmetaconular cristae.
specifically MNHN CAS 681 and 683. The pre- and postprotocrista will be regarded as
the crests connecting the apex of the protocone to
7.Protolipternidae the conules (Nessov. et al.1998).
Asmithwoodwardia scotti Paula Couto, 1952 (see In Figure1 the taxon on which the nomenclature
also Paula Couto 1978; Cifelli 1983a): DGM is based is Molinodussuarezi. The upper molars of
358M (holotype), 410M, MCT 2313M this species have a conspicuous labial cingulum,
(Itaboraí, Brazil; Itaboraian). Asmithwoodwardia i.e. a crest separated from the para- and meta-
is a small dentally primitive ungulate from the late cones by a valley. In other taxa (e.g., Pucanodus)
Palaeocene of Brazil and Patagonia. A. scotti was there is no true cingulum. The bases of the para-
initially referred by its author (Paula Couto and metacones are swollen but there is no crest
1952) to the hyopsodontine hyopsodontids. and valley as are observed in Molinodus. In this
Later, Paula Couto (1978) referred this genus to case the structure observed will be termed “labial
the didolodontids, and Cifelli (1983a, 1993a) re- rim” in order to better describe the actual mor-
gards Asmithwoodwardiaas a primitive litoptern. phology of this part of the tooth.
Miguelsoria parayirunhor (Paula Couto, 1952) On the upper premolars, the crista joining the
(see also Cifelli 1983a): MNRJ 1460V, 1468V paracone to the metastyle has been termed
54 GEODIVERSITAS • 2000 • 22 (1)
“Condylarths” from the early Palaeocene of Bolivia
postparacrista
labial cingulum
paracone
ectoflexus
preparacrista
premetacrista parastyle
metacone paracingulum
postmetacrista
trigon basin
metastyle
preparaconular
metacingulum crista
postmetaconular
paraconule
crista
metaconule precingulum
postcingulum
preprotocrista
postprotocrista
protocone A
metaconid
trigonid basin
entoconid
talonid basin paraconid
hypoconulid
paracristid
hypoconid
postcingulid precingulid
cristid obliqua protoconid
protocristid
B
FIG.1.—Terminology used for molar morphology; A, right upper molar; B, right lower molar; both in occlusal view.
GEODIVERSITAS • 2000 • 22 (1) 55
MuizonC.de & CifelliR.L.
paracrista rather than metacrista (as in Nessov et UCMP University of California, Museum of
al. 1998) mainly because none of the known Paleontology, Berkeley, California,
upper premolars of Kollpaniinae bears a meta- USA;
cone even incipient. UM Museum of Paleontology, University
In the discussion, the term “primitive”, when of Michigan, Ann Arbor, Michigan,
applied to taxa, is regarded a as synonym of USA;
“archaic” or “generalized” according to recom- UMVP University of Minnesota, Vertebrate
mendations of Prothero et al. (1988), i.e. a taxa Paleontology Collection, Minneapolis,
which retains many plesiomorphic character Minnesota, USA;
states. UNPSJB PV Palaeontology collections of the
Universidad Nacional de la Patagonia,
Comodoro Rivadavia, Argentina;
ABBREVIATIONS FOR INSTITUTIONS CITED IN THE USNM United States National Museum of
TEXT Natural History, Washington, DC,
AMNH American Museum of Natural History, USA;
New York, USA; YPFB Pal Yacimientos Petrolíferos Fiscales
BUNM Bureau of Land Management Col- Bolivianos, Colección de Paleonto-
lection, University of New Mexico, logía, Santa Cruz, Bolivia;
Albuquerque, New Mexico, USA; YPM (PU) Princeton Collection, Yale Peabody
CCMGE Chernyshev’s Central Museum of Museum, New Haven, USA.
Geological Exploration of Saint
Petersburg, Russia;
DGM Divisão Nacional de Produção
Mineral, Rio de Janeiro, Brazil; and SYSTEMATIC PALAEONTOLOGY
DNPM
DMNH Denver Museum of Natural History, Supergrandorder UNGULATOMORPHA
Denver, Colorado, USA; Archibald, 1996
KU Museum of Natural History,
University of Kansas, Lawrence, Order PANAMERIUNGULATA nov.
Kansas, USA;
MACN Museo Argentino de Ciencias Family MIOCLAENIDAEOsborn & Earle,1895
Naturales, Buenos Aires, Argentina;
MCT Museu de Ciencia da Terra, Rio de INCLUDED GENERA. — Andinodus, Bubogonia,
Choeroclaenus, Ellipsodon, Escribania, Litaletes,
Janeiro, Brazil;
Mioclaenus, Molinodus, Orthaspidotherium, Pleuraspi-
MHNC Museo de Historia Natural de Cocha- dotherium, Promioclaenus, Protoselene, Pucanodus,
bamba, Bolivia; Simoclaenus, Tiuclaenus, Tiznatzinia, Valenia.
MLP Museo de La Plata, Division de Pa-
DIAGNOSIS.—Bulbous cusps, the apices of which are
leontología de Vertebrados, La Plata, approximated in occlusal view; protocone enlarged;
Argentina; stylar shelf reduced to a labial cingulum or lost; styles
MNHN Muséum national d’Histoire naturelle, of M1-2 reduced and tending to be aligned with para-
and metacristae; paraconid reduced, tends to merge
Paris, France;
with the metaconid; entoconid and hypoconulid con-
MNRJ Departamento de Geología e Mine-
nate to fused, forming an obliquely oriented pos-
ralogía, Museu Nacional de Rio de terolingual crest; entoconid compressed transversely
Janeiro, Brazil; on P4 parastyle reduced and postparacrista straight,
SPSM Saint Paul Science Museum, Saint not curved labially.
The character states presented in this diagnosis are
Paul, Minnesota, USA;
derived when compared to Protungulatum, Oxyprimus
UALVP Laboratory for Vertebrate Palaeonto-
and “zehlestids”. However, it is noteworthy that most
logy, University of Alberta, Edmonton, of these characters are highly homoplastic and are
Canada; observed in several other groups of “condylarths”.
56 GEODIVERSITAS • 2000 • 22 (1)