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2-1975
Scimitar-toothed Cats, Machairodus and Nimravides, from the Pliocene of Kansas and Nebraska
Larry D. Martin
C. Bertrand Schultz
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This Article is brought to you for free and open access by the Museum, University of Nebraska State at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Bulletin of the University of Nebraska State Museum by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. BULLETIN OF VOLUME 10, NUMBER 1, PART 5 The University of Nebraska State Museum FEBRUARY, 1975
Larry D. Martin C. Bertrand Schultz
Scimitar-toothed Cats, Machairodus and Nimravides, from the Pliocene of Kansas and Nebraska Frontispiece-Restoration of the head of Machairodus c%radensis tanneri from the Pliocene of Kansas and Nebraska. Restoration by Mary Tanner. X 1/4. Larry D. Martin C. Bertrand Schultz
CENOZOIC MAMMALS FROM THE CENTRAL GREAT PLAINS
Part 5 Scimitar-toothed Cats, Machairodus and Nimravides, from the Pliocene of Kansas and Nebraska
BULLETIN OF The University of Nebraska State Museum VOLUME 10, NUMBER 1, PART 5 FEBRUARY, 1975 BULLETIN OF VOLUME 10, NUMBER 1, PART 5 THE UNIVERSITY OF NEBRASKA STATE MUSEUM FEBRUARY, 1975
PP.55-63, Frontispiece, Figs. 1-5
ABSTRACT
Part 5. Scimitar-toothed Cats, Machairodus and Nimravides, from the Pliocene of Kansas and Nebraska
Larry D. Martin C. Bertrand Schultz
"Machairodus catocopis Cope" is shown to be a pseudaelurin cat belonging to the genus Nimravides Kitts. Nimravides thinobates (Macdonald) is a possible synonym of N. catocopis (Cope). Nimravides is compared with the Eurasian Machairodus-like cat, Dinofelis. Machairodus (HeterofeJis) coloradensis is reported from the Kimball Formation, upper Pliocene (Kimballian) of Cheyenne County, Nebraska, and from the upper part of the Ash Hollow Formation, Pliocene (Hemphillian) of Sherman County, Nebraska. The Kimballian form is described as a new sub species, Machairodus coloradensis tanneri.
CONTRIBUTION OF The Department of Geology, College of Arts and Sciences, and the Division of Vertebrate Paleontology of the Museum. Martin1, Schultz2
Scimitar-toothed Cats, Machairodus and Nimravides, from the Pliocene of Nebraska and Kansas3
INTRODUCTION coloradensis in synonomy with M. catocopis and this concept has generally been followed. New The genus Machairodus has long been as material from Smith County, Kansas, which is sociated with the Hemphillian of North America near the type locality and horizon of M. and the Pontian of Eurasia. It was first reported Catocopis, permits a reevaluation of that species from North America when Cope, in 1887, de and shows that it is a pseudaelurin cat, scribed a partial symphysis of a mandible from Nimravides. Machairodus coloradensis is re the Pliocene of Kansas as Machairodus ported from the Upper Ash Hollow deposits catocopis. He did not illustrate this specimen, (Hemphillian) of Sherman County, Nebraska, and it has largely been ignored (see Fig. 3, C and and is compared to a new subspecies of E in the present paper). The concept of the Machairodus described in this paper from the species has rather been based on abundant Kimball (Kimballian) Formation of Cheyenne material from Ogallala deposits (Hemphillian) of County, Nebraska. This new subspecies demon Yuma County, Colorado, described by Cook strates evolutionary trends which seem to be (1922) as M. (Heterofelis) coloradensis; later Burt leading to Ischyrosmilus from the lower Quater (1931) published additional records from the nary (Blancan). We do not regard the pseudaelu Hemphillian of Texas. Matthew (1924) placed M. rin cats to be of subfamily rank, although they probably should be placed in a separate tribe, Pseudaelurini, which represents primitive 'Assistant Curator of Vertebrate Paleontology, University felines. of Kansas Museum of Natural History, and Assistant Profes sor of Systematics and Ecology, University of Kansas, Law rence; Research Affiliate, University of Nebraska State 31n the present paper "Pliocene" includes the Valentinian, Museum. Clarendonian, Hemphillian, and Kimballian provincial ages, 2Curator of Vertebrate Paleontology, University of Ne although the writers realize that only the Kimballian may be braska State Museum, and Professor of Geology, Depart equivalent to the latest Miocene of Europe. See Part 1, p. 2, ment of Geology. of the present Bulletin for further remarks on this subject. 56 / BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM
SYSTEMATIC DESCRIPTIONS
Class: MAMMALIA Order: CARNIVORA Family: FELIDAE Gray, 1821 Subfamily: Machairodontinae Gill, 1872 Genus: Machairodus Kaup, 1833
Machairodus aphanista (Kaup) Geographic Distribution.-North America, Eurasia, and Africa. Amended Diagnosis.-Scimitar-toothed cats about the size of a lion (Panthera leo); skull with a relatively elongate face; upper canines large, blade-like, and coarsely serrated; lower canine greatly reduced and incisiform; upper and lower incisors evenly spaced and arranged in a semicircle; upper carnassial with protocone re duced; metaconid very reduced or lost on lower carnassial; P2 usually absent; coronoid process on ramus low; limbs elongate; and feet digiti grade. Machairodus cf. coloradensis Cook, 1922 Machairodus catocopis Matthew, 1924; Burt, 1931; Savage, 1941; Mawby, 1965; Shotwell, 1956; and Dalquest, 1969. Type Locality.-Near Wray, Yuma County, Colorado. Fig. 1 -A, Machairodus cf. c%radensis, U.N.S.M. 25510, right ramus (crown and labial views), and B, right canine Stratigraphic Occurrence.-Middle Pliocene, (labial view) from the upper part of the Ash Hollow Forma Ogallala Group, upper part of Ash Hollow Forma tion, Sherman County, Nebraska; C, Nimravides catocopis, tion. U.N.S.M. 21819, distal end of humerus, from the upper part of the Ash Hollow Formation, Smith County, Kansas. X 1/2. Referred Specimen.-Right CJ; right ramus with !1-2(alv.), 13, IC, P3-4(alv.), Ml, U.N.S.M. 25510 (Fig. 1, A and B). Amended Diagnosis.-Scimitar-toothed cat intermediate in size between jaguar and lion; Locality.-U.N.S.M. Coil. Loc. Sm-101, SV2, dorsal surface of skull rounded and occiput in SW. V4, sec. 13, T. 16N., R. 13W. East of Ashton, clined as in feline cats; upper canine flattened Sherman County, Nebraska. and crenulated on anterior and posterior edges; Stratigraphic Occurrence.-Middle Pliocene p3 double-rooted and relatively large with a large (Hemphill ian), Ogallala Group, Ash Hollow For posteriorly directed paracone, well-developed mation. parastyle and metacone of about equal size; p4 SCIMITAR-TOOTHED CATS, MACHA/ROD US AND N/MRAVIDES, FROM THE PLIOCENE / 57 Fig.2-Machairodus c%radensis tanneri, new subspecies, holotype, U.N.S.M. 26086, right ramus (labial and lingual views), from the Kimball Formation, Cheyenne County, Nebraska. large with a prominent anterior cusp on the of Agriotherium. The skeleton of the North parastyle (absent or very small in Nimravides), American Machairodus has been described by protocone well developed, metacone elongate Dalquest (1969) and shows the long-legged and blade-like; M' small (absent in Nimravides); form, typical of scimitar-toothed cats. The lower ramus with anterior margin inclined; coronoid canine is in place in U.N.S.M. 25510 and has the process low (higher in Nimravides); anterior form illustrated by Burt (1931, pI. 45) contrary mental foramen larger than in Nimravides; in to Dalquest (1969, p. 16). The species of cisors graded in size becoming larger from 11-3, Machairodus need a thorough revision, and a recurved and serrated on both edges (crowded good series of the North American forms should in Nimravides); lower canine reduced in size, in be studied. The four rami of M. coloradensis cisiform, and serrated anteriorly and posteriorly; reported by Cook (1922) show considerable vari P3-4 large and double-rooted; M, larger than in ation in size and morphology. The smaller Nimravides and more posteriorly located, ramus, No. 207, that he illustrates (Cook, 1922, p. paraconid almost as large as protoconid; 24) resembles U.N.S.M. 25510 in the lack of a metaconid very small or absent. dependent flange on the ramus, the lack of de velopment of the metaconid on M" and in its Discussion.-The diagnosis is based in part relatively small size. The other rami illustrated on figures in Cook (1922) and Burt (1931). are much larger and appear to have prominent Cook's figures are of poor quality and it is dif metaconids on M,. ficult to ascertain the nature of the metaconid on M, which he mentions. It is absent from all other specimens of Machairodus that have been de Machairodus c%radensis tanneri,4 new sub scribed from North America (Mawby, 1965). The species upper canine of U.N.S.M. 25510 has large crenu lations on its anterior and posterior margins. It Holotype.-Right ramus with 11-3 alv., IC rt., seems well adapted for slashing and contrasts P3-M, broken, U.N.S.M. 26086; Figs. 2, 3A. with the stabbing saber with fine crenulations found in Barbourofelis. U.N.S.M. 25510 was 4Named in honor of Lloyd G. Tanner who has contributed much to a found in association with undetermined better understanding of the Kimballian fauna and the Kimball Forma rhinoceros remains and an undescribed species tion. 58 / BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM E ~------~------ Fig. 3 -A, Machairodus c%radensis tanneri, new subspecies, holotype, U.N.S.M. 26086, ramal symphysis (anterior view), from the Kimball Formation, Cheyenne County, Nebras ka; B, D, F, G, Nimravides catocopis referred: B, U.N.S.M. 21818, mandibular symphysis (anterior view), from Smith Cou nty Kansas; D, U.N.S.M. 21817, partial left maxillary (labial view), from Smith County, Kansas; F, U.N.S.M. 21818, partial left ramus (labial view), P3-4 and the side of the ramus below the cheek teeth restored from the left side of the mandibl e, from Smith County, Kansas; G, U.N.S.M. 45116, left ramus (labial view), from Frontier County, Nebraska; C, E, Nimravides catocopis, holotype, A.M.N.H. 8318, from Phillips County, Kansas; C. mandibular symphysis (anterior view); E, mandibular symphysis, (labial view). X 1/2. SCIMITAR-TOOTHED CATS, MACHAIRODUS AND NIMRAVIDES, FROM THE PLIOCENE I 59 A c Fig. 4 -Outlines of right incisor and canine alveolae: A, Machairodus cf. coloradensis, U.N.S.M. 25501, from the upper part of the Ash Hollow Formation, Sherman County, Nebraska; Band C, Nimravides catocopis, B, holotype, A.M.N.H. 8318, from Phillips County, Kansas; C, referred, U.N.S.M. 21818, from Smith County, Kansas. X 1. Type Locality_-U.N.S.M. Coil. Loc. Cn-101, Colorad 0 (Cook, 1922), and from the Coffee NW. Y4, sec. 23, T. 15N., R. 49W., 41/2 miles south Ranch Local Fauna at Hemphill, Texas (Burt, and 31/2 miles east of Gurley, Cheyenne County, 1931; Dalquest, 1969). It seems to have a better Nebraska. developed dependent flange on the ramus and to differ from M. c. coloradensis in lacking the Stratigraphie Occurrence.-Upper Pliocene metaconid on Ml. It may also have a lower (Kimballian), Ogallala Group, Kimball Formation. coronoid process, although damage to U.N.S.M. Diagnosis.-A scimitar-toothed felid with a 26086 makes it impossible to determine this with well-developed, dependent flange on the ramus certainty. and two roots on P3. Subfamily: Felinae Trouessart, 1885 Description.-Mandible very elongate; coronoid process low; masseteric fossa large, deep, and extending under middle of Ml; angu Nimravides Kitts, 1958 lar process an elongated knob; flange excavated Type Species.-Nimravides thinobates for saber; contour of dependent flange similar to (Macdonald), 1942. that in Ischyrosmilus; anterior border of sym physis square with two large foramina as in Geographic Distribution.-California, Texas, Ischyrosmilus; alveolae show incisors slightly Oklahoma, Kansas, and Nebraska. crowded; IC root flattened laterally; diastema Amended Diagnosis.-Very large pseudaelu relatively long; P3 with two roots; P4 slightly rin cats; anterior buccal side of ramus flattened tilted posteriorly; Ml moderately large. and excavated in a manner analogous to the Discussion.-Machairodus coloradensis tan condition in Machairodus; ventral symphysial neri is highly advanced in terms of the develop extension projecting further ventrally than in ment of a distinct dependent flange on the Pseudaelurus; p4 with elongate (blade-like) ramus. It mig ht make a good ancestor for metacone, and large parastyle; upper and lower Ischyrosmilus, from which it differs in having P3 carnassial notches more shallow than in much less reduced and the mandible more elon Pseudaelurus but not as shallow as in gate. It would have been contemporaneous with Machairodus; lower carnassial having the giant dirk-toothed cat Barbourofelis fricki, metaconid but usually lacking talonid and Machairodus coloradensis tanneri might be (metaconid absent or extremely vestigial in represented by some undescribed skeletal ele North American Machairodus); lower carnassial ments from U.N.S.M. Coil. Loc. Ft-40, the type relatively smaller than in Machairodus; lower in locality for Barbourofelis fricki. cisors small and crowded as in Pseudaelurus In size U.N.S.M. 26086 falls well within the (larger and more evenly spaced in Machairodus); range given for Machairodus from Yuma County, anterior margin of ramus less prognathous than 60 / BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM Machairodus sp.: Burt, 1931. Machairodus coloradensis: Savage, 1941. Holotype.-Symphysis of a mandible with 11-3(alv.), C (br.); A.M.N.H. 8318 (Fig. 3, C and E). Type Locality.-Republican River beds, Phil lips County, Kansas. Stratigraphie Occurrence.-Pliocene (?Hem phillian), Ogallala Group, Ash Hollow Formation. Referred Specimens.-Partial maxilla with p3·4, U.N.S.M. 21817 (Fig. 3,0); partial mandible with 11·3(alv.), IC(br.), P2(alv.)-Ml, U.N.S.M. 21818 (Fig. 3, B, F; 4, C); partial right ramus with 11·3(alv.), IC(alv.) and P3(alv.), U.N.S.M. 21816; dis tal end of humerus, U.N.S.M. 21819, all from Smith County, Kansas; and right ramus with h·3(alv.),/C, P3(alv.), P4, Ml(alv.), U.N.S.M. 45116 (Fig. 3, G), from upper part of the Ash Hollow Formation, Frontier County, Nebraska. Localities.-U.N.S.M. Coil. Loc. Kan-1, Smith County, Kansas, and U.N.S.M. Coil. Loc. Ft-47, upper part of Ash Hollow Formation, Frontier County, Nebraska (more precise locality and stratigraphic data is available from the locality files of the University of Nebraska State Museum). Stratigraphic Occurrence.-Pliocene (Hem c phillian), Ogallala Group, upper part of Ash Hol low Formation. Diagnosis.-Not distinguished from ·generic diagnosis. The only other described species, Fig. 5 -Restoration of outlines of skulls: A, Machairodus coloradensis (based on Cook, 1922); B, Nimravides thino Nimravides thinobates (Macdonald), is a proba bates (based on Kitts, 1958, PI. 1 and Macdonald, 1948); C, ble synonym. Dinofelis diastemata (after Hemmer, 1965, Fig. 36). Approx imately X 1/4. Discussion.-The holotype of Nimravides catocopis has the anterior-buccal margin to the in Machairodus; coronoid process high as in ramus less excavated, the ventral margin of the Pseudaelurus but with broader base and more symphysis less angular, the canine larger, and recurved posteriorly than in Machairodus; mas the incisors smaller and more crowded than in seteric fossa larger and with a thinner ventral Machairodus. It resembles Nimravides in all of border than in Pseudaelurus. these features. The partial mandible, U.N.S.M. 21818, is as close to being a topotype of N. Nimravides catocopis (Cope), 1887, new combi catocopis as we can reasonably hope to find nation with the data available. It agrees with the holotype on almost all visible features. It demon Machairodus catocopis: Cope, 1887; Hesse, strates that the carnassial was smaller and not as 1940. posteriorly placed as in Machairodus coloraden- SCIMITAR-TOOTHED CATS, MACHA/ROD US AND N/MRAV/DES, FROM THE PLIOCENE I 61 sis. The lower canine of Nimravides does not expressions of a persistent tendency in feline have the extensive anterior and posterior serra cats to revert to the saber-toothed condition. The tions found in Machairodus (Burt, 1931, PI. 45). living cloud leopard (Neofelis nebulosus) The P2 was present in U.N.S.M. 21818 but was represents another example. In North America, absent in U.N.S.M. 21816 from the same locality. Machairodus may have given rise to The P3 is a large tooth with a well developed Ischyrosmi1us, a genus which would then be paraconid, protoconid, and talonid. The valid and should not be put into synonomy with paraconid is very large on P4 while M1 has a Homotherium as has been suggested (Mawby, small metaconid and no talonid. p3 has a large 1965; Churcher, 1968).The P2 of Nimravides was parastyle, paracone, metacone, and a well a small Single-rooted peg-like tooth which seems developed posterior cingular cusp as described to have been present in a fairly high percentage in Kitts (1958, p. 373). The upper carnassial is of the population, and also often occurs in badly damaged, but seems to have been similar Pseudaelurus. to that illustrated by Macdonald (1948, Fig. 14). Kitts (1958) includes a substantial amount of The M1 is unfortunately not preserved. size variation in his concept of N. thinobates. If The lower carnassial referred by Savage (1941, this amount of variation is accepted, N. thino p. 697) to Machairodus (Heterofelis) coloraden bates (Macdonald) may be a synonym of N. sis on the basis of its prominent metaconid may catocopis (Cope). All of the specimens from for that same reason be better placed in Smith County, Kansas, are near the size of the Nimravides catocopis, while the specimen lack holotype of N. catocopis and the smaller speci ing the Metaconid from Optima may be a men from Arnett, but the specimen from Machairodus. U.N.S.M. Coil. Loc. Ft-47 is near the size of the larger specimen from Arnett. CONCLUSION Kitts did not compare Nimravides with the es sentially similar machairodontoid pseudaelurin The typical scimitar-toothed cat of the cat of Eurasia, Dinofelis. Dinofelis does not usu Pliocene is Machairodus. It apparently origi ally have a well-developed metaconid on the nated in Eurasia from the Miocene scimitar lower carnassial as does Nimravides. It does toothed cat Nimravus and spread through most have the anterior margin of the symphysis more of the Northern Hemisphere. The time of its arri inclined. Dinofelis barlowi has a large metaconid val in North America is presently uncertain, and on M1. Both genera have large lower canines, we are not aware of any records older than Hem high coronoid processes, and generally similar phillian. It seems probable that it migrated to skull configuarations (Fig. 5). It appears that North America at the same time as the Nimravides, like Dinofelis, lacks serrations on postorbital-bar cats, the Barbourofelini. The lat the upper canine, while Machairodus and ter first appear in North America during the Ischyrosmilus have coarsely serrated upper Clarendon ian (Schultz, Schultz, and Martin, canines. Dinofe/is has the auditory bulla sepa 1970). Although several species of North Ameri rated into two parts, as do other pseudaelurin can felids have been referred to Machairodus, cats (Piveteau, 1948). The auditory bulla of only M. coloradensis Cook seems to be valid. Nimravides has not been described although we Machairodus hesperus Gazin from the Early would expect it to be similar to that found in Pleistocene of Idaho has been shown to be a Dinofelis. It is possible that these cats may be Megantereon (Schultz and Martin, 1970), closely related although they are widely sepa Machairodus niobrarensis (Thorpe) is a bar rated in the phylogenetic tree published by bourofelin cat,S and M. catocopis Cope belongs Thenius (1967, Fig. 1). Kurten (1972) has shown to the genus Nimravides Kitts. that Panthera palaeoonca Meade is a species of Nimravides is closely similar to the Eurasian Dinofelis. The latter genus is now known from machairodontoid cat Dinofelis. Both genera are the Blancan of North America and the Villafran chian of Eurasia and Africa. It is possible that it SMartin, manuscript in preparation. was derived from Nimravides in North America 62 I BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM TABLE 1 Machairodus and Nimravides COMPARATIVE MEASUREMENTS' OF MANDIBULAR RAMI Machairodus coloradensis Nimravides MANDIBULAR RAMI tanneri, n. subsp. Nimravides catocopis Holotype M. coloradensis catocopis U.N.S.M.45116 U.N.S.M. 26086 U.N.S.M.25510 U.N.S.M.21818 U.N.S.M.21817 Distance between alveoli for IC and P3 ...... 39 29.5 26.3 40.2 Depth of ramus posterior to M, ...... 44.1 39.2 37.6 49.3 Thickness of ramus below M, ...... 19.2 18.2 18.7 23 Height from inferior border of angle to summit of condyle ...... 40.7 42.3 (45)2 Height from inferior border of angle to summit of coronoid process ...... (73.6) (103.6) Transverse width of condyle ...... 42 h greatest anteroposterior diameter ...... (12.5) (9.6) I, greatest transverse diameter ...... (4.7) (3.5) 12 greatest anteroposterior diameter ...... (13.8) (9.6) 12 greatest transverse diameter ...... (7.4) (5.2) b greatest anteroposterior diameter ...... 9.5 b greatest transverse diameter ...... 9.1 IC greatest anteroposterior diameter at base of enamel ...... (19.2) 15.5 20.5 20 IC greatest transverse diameter ...... 12.8 13.2 12 12.1 Length P3-M, ...... 78.8 77.6 65.8 P2 anteroposterior diameter ...... 3.6 P2 greatest transverse diameter ...... 3.0 P3 anteroposterior diameter ...... (19.6) (20) 17.1 (19.2) P3 greatest transverse diameter ...... (7.9) (7.8) 8.3 P4 anteroposterior diameter ...... (26.3) (26.4) 21.9 23.9 P4 greatest transverse diameter ...... (10.5) (10.2) 9.4 10.7 M, anteroposterior diameter ...... (32.0) 31.9 25.4 (28.6) M, greatest transverse diameter ...... (12.6) 14 11.6 M, length of protoconid blade ...... 13.5 12.4 UPPER DENTITION CI greatest anteroposterior diameter ...... 38.4 CI greatest transverse diameter ...... 15.8 p3 anteroposterior diameter'...... 21.4 p3 greatest transverse diameter ...... ' ... . 10.0 . p4 anteroposterior diameter ...... : ...... 31.3 p4 greatest transverse diameter ...... 13.6 'The measurements are taken to the nearest millimeter except on dentition where they are measured to the nearest one tenth of a millimeter 2( ) = alveolar or approximate measurement SCIMITAR-TOOTHED CATS, MACHA/RODUS AND N/MRAVIDES, FROM THE PLIOCENE I 63 and then migrated to Eurasia during the Blancan Cope, E. D. 1887. A saber-tooth tiger from the Loup Fork. as did the early lynxes, Amer. Nat. 21: 1019-1020. Dalquest, W. W. 1969. Pliocene Carnivores of the Coffee Ranch (Type Hemphill) Local Fauna. Bull. Texas Memorial ACKNOWLEDGMENTS Mus. (15): 1-43, Figs. 1-11, 1 plate, 31 tables. Hemmer, H. 1965. Zur Nomenklatur und Verbreitung des The writers are grateful to Messrs. Dick Her Genus Dinofelis Zdansky, 1924 (Therailurus Piveteau, man and Leonard Egging for the discovery of the 1948). Paleont. Africana 9: 78-89, 4 figures. holotype of Machairodus coloradensis tanneri, Hesse, Curtis J. 1940. A Pliocene vertebrate fauna from Hig U.N.S.M. 26086, and for reporting the fossil gins, Lipscomb County, Texas. Univ. Texas Publ. 3945: 671-698,8 figures. quarry, U.N.S.M. Coli. Loc. Cn-101, from Kitts, D. B. 1958. Nimravides, a new genus of felidae from the Cheyenne County to the Museum's Division of Pliocene of California, Texas and Oklahoma. Jour. Mam Vertebrate Paleontology. They are also thankful mal. 39: 368-375 to Mr. Dale Anderstrom for the donation of the Kurten, B. 1972. The genus Dinofe/is (Carnivora, Mammalia) Machairodus specimen, U.N.S,M. 25510, from in the Blancan of North America. Univ. Texas Bull., Pearce-Sellards Ser. (19); 1-7, 1 figure, 1 table. Sherman County. The Smith County (Kansas) Macdonald, J. R. 1948. The Pliocene carnivores of the Black specimens, U.N.S.M. 21816, 21817, 21818, and Hawk Ranch. Univ. California Publ. Geol. Sci. 28: 53-80, 15 21819, were collected in 1931 by a University of figures. Nebraska State Museum field party consisting of Matthew, W. D. 1924. Third contribution to the Snake Creek Messrs. Emery L. Blue, Frank Crabill, Eugene Fauna. BUll. Amer. Mus. Nat. Hist. 50 (2): 59-210, 63 fig ures. Vanderpool, and C. Bertrand Schultz; and the Mawby, J. E. 1965. Machairodonts from the Late Cenozoic of Frontier County (Nebraska) specimen, U.N.S.M. the Panhandle of Texas. Jour. Mammal. 46(4): 573-587, 45116, was collected in 1948 by a U.N.S.M. field Figs. 1-5. party which was under the direction of Messrs. Piveteau, J. 1948. Un Felide du Pliocene de Rousillon. Ann. W. D. Frankforter and C. Bertrand Schultz. Mr. Paleont. 34: 97-124. Savage, D. E. 1941. Two new middle Pliocene Carnivores Jerry Tanner prepared the illustrations for Figs. from Oklahoma, with notes on the Optima fauna. Amer. 1, 2, 3A, and 3D, and Mrs. Mary Tanner was re Midland Nat. 25(3): 672-710, Figs. 1-40,4 plates. sponsible for the drawings in Figs. 4 and 5, and Schultz, C. B., and L. D. Martin. 1970. Machairodont cats also 3B, 3C, 3E, 3F, and 3G. The writers are from the Early Pleistocene Broadwater and Lisco Local grateful to Mrs. Mary Tanner and Mr. George faunas. Bull. Univ. Nebraska State Mus. 9(2): 1-36, Figs. 1-2, Frontispiece. Corner for their help in the preparation of the Schultz, C. B., M. R. Schultz, and L. D. Martin. 1970. A new manuscript. tribe of saber-toothed cats (Barbourofelini) from the Pliocene of North America. Bull. Univ. Nebraska State Mus. REFERENCES 9(1): 1-31, Figs. 1-13, Frontispiece. Shotwell, J. A. 1956. Hemphillian mammalian assemblage Burt, W. H. 1931. Machaerodus catocopis Cope from the from northeastern Oregon. Bull. Geol. Soc. Amer. 67: Pliocene of Texas. Univ. California Publ., Bull. Dept. Geol. 717-738, Figs. 1-7. Sci. 20(7): 261-292, 8 plates. Thenius, E. 1967. Zur Phylogenie der Feliden (Carnivora, Churcher, C. S. 1966. The affinities of Dinobastis serus Cope Mamm.). Zeitschrift Zool. Syst. Evolutionsforschung 5(2): 1893. Quaternaria (8): 263-275. 129-143, 1 fig ure. Cook, H. J. 1922. A Pliocene fauna from Yuma County, Col orado, with notes on the closely related Snake Creek Beds of Nebraska. Proc. Colo. Mus. Nat. Hist. 4(2): 3-15, 14 fig ures.