Los Angeles Museum Publication No. 2

QUATERNARY ANTELOPE REMAINS FROM A SECOND CAVE DEPOSIT IN THE ORGAN MOUNTAINS, by CHESTER STOCK

Science Series No. 2 Paleontology No. 2 PP. 1-18, 3 Figs. in Text

Los Angeles,

May 29, 1930 List of Illustrations Introduction . Tetrameryx(?) conk/ingi Description of Materia' Axial Skeleton Appendicular Skeletc Conclusions

LI

Fig. 1. Tetrameryx (?) NOTICE holotype, No. Reference to or citations from this 175; fig. 1 c, n publication should be made by x 1.0. Los A page and publication number only. deposits, Shelt Fig. 2. Tetrameryx (?) No. 179, ante1 No. 180, anter Museum Col Cave, Organ I\. Fig. 3. Tetrameryx (?) cannon bone, r 3 b1, posterior c views; x 1.0. nary deposits, CONTENTS PAGE List of Illustrations 3 Introduction . 5 Tetrameryx(?) conklingi, n. sp. 6 Description of Material Axial Skeleton 6 Appendicular Skeleton 13 Conclusions 18

LIST OF ILLUSTRATIONS

Fig. 1. Tetrameryx (.?) conklingi, n. sp. Fig. la, left horn cores, holotype, No. 174; fig. 1 b, right anterior horn core, No. this 175; fig. 1 c, ramus of mandible, No. 176; lateral views, ' by x 1.0. Los Angeles Museum Collection. Quaternary mlj. deposits, Shelter Cave, Organ Mts., New Mexico 7

1 Fig. 2. Tetrameryx (?) conklingi, n. sp. Fig. 2a, 2a , humerus, No. 179, anterior and distal views; fig. 2b, 2b1, radius, No. 180, anterior and distal views; x 1.0. Los Angeles Museum Collection. Quaternary deposits, Shelter Cave, Organ Mts., New Mexico. 11 Fig. 3. Tetrameryx (.?) conklingi, n. sp. Fig. 3a, 3a1, anterior cannon bone, No. 185, anterior and lateral views; fig. 3 b, 3b1, posterior cannon bone, No. 187, anterior and lateral . views; x 1.0. Los Angeles Museum Collection. Quater- nary deposits, Shelter Cave, Organ Mts., New Mexico. 15 QUATERNARY ANTELOPE REMAINS FROM A SECOND CAVE DEPOSIT IN THE ORGAN MOUNTAINS, NEW MEXICO by CHESTER STOCK

INTRODUCTION Explorations conducted by Mr. Roscoe P. Conkling during the past two years in the Organ Mountains of southern New Mexico have led to the discovery of two limestone caverns in the lower spurs of this 1 range. Attention has been directed to the deposits of Conkling Cave • The second occurrence is that of Shelter Cave, situated in Paleozoic limestones exposed on the west flank of Bishop's Cap (Pyramid) Peak, approximately two and one-half miles west and south of Conkling Cave. In the course of preliminary excavations in this cavern a vertebrate assemblage was collected including among other forms a horse (Equus), the ground sloth Nothrotherium, and a peculiar type of antelope. The remains of these were all found, according to Mr. Conkling, within 48 inches of the present floor of the cave and imbedded in a gray ash deposit. The presep.ce of the horse, ground sloth and antelope indicates a Quaternary age of the cave deposits. No less than three i~dividuals of the new antelope are recorded. A second type of antelope, larger in size than the first and approaching more closely the modern prong­ horn in several characters, is represented by fragmentary specimens in the collection. Whether or not the two forms were contemporaneous has not been definitely determined. The preservation of the jaw and limb material of the larger antelope is somewhat unlike that of the specimens referred to the new species and is perhaps indicative of later age. The interest which attaches to a group so distinctively North American as the and the unique characters presented by the small antelope from Shelter Cave inake a description of the remains desirable in advance of a more detailed investigation of the deposit and fauna.

1Bryan, Wm. Alanson, The recent bone-cavern find at Bishop's Cap, New Mexico, Scicncr, N. S., vol. 70, pp. 39-41. 1929. 6 Los ANGELES MusEUM PUBLICATION No. 2 STOCK: QUATERNARY

TETRAMERYX(?) CONKLING!, N. SP. Holotype.- A fragment of the orbital portion of the frontal with horn cores of the left side, No. 174, Los Angeles Museum Collection, Vertebrate Paleontology. Paratype.- A single (anterior) horn core, No. 175, L.A. Mus. Coll. Vert. Pale. ~·\: :~ : ...t: Referred material.- Right ramus of mandible, No. 176; vertebrae, ~ ., . c Nos. 191, 192, 201; mesosternal segments, No. 189; scapula, No. 198; ~ :,~;',_.;/· I' ' humerus, No. 179; radii, Nos. 180, 182, 183; anterior cannon bones, I

Nos. i84, 185; posterior cannon bone, No. 187; L. A. Mus. Coll. Vert. \ Pale. O' './, Locality.-Shelter Cave, Organ Mts., Dona Ana County, New Mexico. L. A. Mus. Loe. No. 1010. Specific characters.- Forked horn cores, arising from a common base, present on each side above and in part slightly behind orbit. Anterior horn core slightly stouter and longer than posterior; hinder not so greatly elongated as in Tetrameryx shuleri Lull. Base of anterior horn core relatively wider than in latter species. Horn cores divergent a as in Tetrameryx, not parallel as in minor Taylor. Size distinctly smaller than T. shuleri and approximately two-thirds that of existing . Metapodials relatively heavier than in Antilocapra americana (Ord).

DESCRIPTION OF MATERIAL AXIAL SKELETON Horn cores.- The most complete material representing these structures is the holotype, No. 174, figure 1 a, presumably of a young adult. That the size of the prongs is subject to some individual var­ iation is indicated by the difference in stoutness of anterior prong between No. 174 and a second specimen, No. 175, fig. 1 b. In the former the anterior prong is slightly stouter than the posterior. A small portion of the tip is broken away and doubtless this horn core was slightly longer than its fellow of the same side. The diverging prongs, arising from a common base make an angle of 25°. Viewed from above the principal axis of each prong is seen to be oblique to the fore and aft axis of the base. An intersection of these axes would Fig. 1. Tetrameryx (?) conkl fig. lb, right anterior horn core occur at a point internal to the base. If the fragment is so oriented x 1.0 Los Angeles Museum C< that the superior margin of the orbit and the supraorbital foramen 'ION No. 2 STOCK: QUATERNARY ANTELOPE REMAINS FROM NEW MEXICO 7

::il, N. SP. tion of the frontal with :les Museum Collection,

fo. 175, L.A. Mus. Coll.

ble, No. 176; vertebrae, . 189; scapula, No. 198; anterior cannon bones, ; L. A. Mus. Coll. Vert.

Jna Ana County, New

msmg from a common · t slightly behind orbit. · than posterior; hinder i Lull. Base of anterior Horn cores divergent yx minor Taylor. Size imately two-thirds that ively heavier than in

RIAL

·ial representing these presumably of a young to some individual var­ :ness of anterior prong .. 175, fig. I b. In the than the posterior. A loubtless this horn core e side. The diverging angle of 25°. Viewed s seen to be oblique to ion of these axes would Fig. 1. Tetrameryx (?) conklingi, n. sp. Fig. la, left horn cores, holotype, No. 174; fragment is so oriented fig. lb, right anterior horn core, No. 175; fig. le, ramus of mandible, No. 176; lateral views, x l.O Los Angeles Museum Collection. Quaternary deposits, Shelter Cave, Organ Mts., e supraorbital foramen New Mexico. 8 Los ANGELES MusEuM PUBLICATION No. 2 S'FOCK: QuATERNA.R

correspond in position with those of the antelope Capromeryx, 11 or12mm. above the c

the anterior prong is seen to arise and to have an upward course similar a porous texture and 1 to the horn cores in the latter genus. Likewise the anterior prong difference in surface tt appears to correspond in position with the horn core of dntilocapra, 2 and the base of the hor in which respect No. 174 is like Tetrameryx shuleri • In tross-section the anterior prong is seen to be rounded, not flattened transversely as in sulcus is marked on ti dntilocapra. While the transverse diameter at the base of this prong extends from the lower differs but slightly from that in the much larger T. shuleri, the margin. Likewise a n anteroposterior diameter is distinctly smaller. external side of the pc In the presence of a posterior prong No. 174 resembles T. shuleri rim. The two sulci co much more closely than does either Capromeryx or dntilocapra. In the Texan species, however, the posterior prong is decidedly longer The supra-orbi ta! j than the anterior and greatly exceeds in length the comparable prong larger than that of C in the form from New Mexico. Possibly the differences noted in the than that of dntilocapi horn cores and the small size warrant a distinct generic recognition of the latter type. That the several individuals occurring at Shelter Mandible.-A sing Cave were of small size, yet apparently had reached an adult stage of development, is suggested by the ramus of the mandible and by vari­ Tetrameryx (?) conk/in ous skeletal elements referred to Tetrameryx (?) conklingi. intermediate in size bet On the other hand it is conceivable that the differences in size dntilocapra americana. of the horn core structures are due to a difference in age, the type possesses, however, a Ii! from Shelter Cave representing presumably a much younger of the horizontal ramu than T. shuleri. The presence of a second individual somewhat larger row is sinuous in No. than No. 174 furnishes perhaps a further intimation that this is the in Capromeryx. In sh~ case. Unfortunately the posterior horn core is not preserved in No. 175. In the collection is a terminal section of a horn core, No. 204, angle T. (?) conklingi approximately 50mm. long and lOmm. wide at the broken lower end. In latter character the f, This specimen differs in surface texture from Nos. 174, 175 and resembles to Odocoileus. The ru! in this respect the adult core in Tetrameryx and ·Capromeryx. A well forward than in dntilo defined sulcus is present and which extends nearly the entire length of the fragment. Possibly No. 204 is to be referred also to T. (.?) All the crowns of conklingi. In the light of the variation in shape of horn core existing alveoli indicate a tot between males and females of dntilocapra americana the difference dntilocapra. The toot between No. 174 and the holotype of T. shuleri may be ascribed in Z8511 from Rancho L part also to a difference in sex. The former may represent a young pronghorn, No. M76C adult female and the latter an adult male. premolar series relativ In No. 174 the smooth and firm surface which characterizes the Tetrameryx. Judging base of the horn cores is carried upward on each prong above the level this tooth was three-! of the notch separating the two prongs. At a point approximately transversely. The too In position of the postt 'Lull, R. S., Fauna of the Dallas sand pits, Amer. Jour. Sci., aer. 5, vol. 2, pp. 163-167, figs. 2 and 3, 1921. resembles dntilocapra rION No. 2 SrocK: QuATERNARY ANTELOPE REMAINS FROM NEw MExrco 9

:ne antelope Capromeryx, 11 or12mm. above the deepest margin of the cleft the surface presents LO upward course similar a porous texture and this type of surface extends to the tip. The wise the anterior prong difference in surface texture between the upper ends of the prongs :>rn core of Antilocapra, 2 and the base of the horn cores is quite marked. A rather well defined luleri • In tross-section ttened transversely as in sulcus is marked on the external surface of the anterior prong and t the base of this prong extends from the lower border of the porous surface toward the orbital larger T. shuleri, the margin. Likewise a more faintly marked sulcus is present on the external side of the posterior prong and extends toward the orbital 174 resembles T. shu/eri rim. The two sulci converge in their downward course. ryx or Anti/ocapra. In ong is decidedly longer The supra-orbital foramen, with broad groove in front, is slightly h the comparable prong larger than that of , although decidedly smaller differences noted in the than that of Antilocapra. inct generic recognition tals occurring at Shelter Mandib/e.-A single ramus, No. 176, referable apparently to reached an adult stage ie mandible and by vari­ Tetrameryx (?) conklingi, is shown in figure 1 c. This specimen is ,'.?) con kl"tngz. . intermediate in size between the jaw of Capromeryx minor and that of t the differences in size Anti/ocapra americana. The small antelope from Rancho La Brea rence in age, the type possesses, however, a lighter jaw, expressed particularly by the thinness 1 much younger animal of the horizontal ramus. The inferior border posterior to the tooth ividual somewhat larger row is sinuous in No. 176, and the vertical ramus is not so broad as imation that this is the in Capromeryx. In shape of vertical ramus and in prominence of the is not preserved in No. ,f a horn core, No. 204, angle T. (?) conklingi differs distinctly from the modern pronghorn. t the broken lower end. In latter character the form from New Mexico exhibits some resemblance s. 174, 175 and resembles to Odocoi/eus. The rugosity on the external surface is situated farther nd·Capromeryx. A well forward than in Anti/ocapra. riearly the entire length referred also to T. (.?) All the crowns of the cheek-teeth are wanting in No. 176. The

.pe of horn core existing alveoli indicate a total number of teeth comparable to that in 0 !mericana the difference Antilocapra. The tooth row is 11.53 longer than in C. minor, No. leri may be ascribed in Z8511 from Rancho La Brea, and 22.53 shorter than in the living may represent a young pronghorn, No. M760. The molar series is relatively large, the premolar series relatively small, in which respect No. 176 resembles which characterizes the Tetrameryx. Judging from an alveolar remnant of the third molar :h prong above the level this tooth was three-lobed with the posterior lobe relatively wide : a point approximately transversely. The tooth is distinctly smaller than that in Neomeryx. In position of the posterior opening of the dental canal T. (?) conk/ingi >r. 5, vol. 2, pp. 163-167, figs. 2 and 3, resembles .dnti/ocapra more than Capromeryx. 10 Los ANGELES MusEuM PUBLICATION No. 2 STOCK: QuATERNAR.

MEASUREMENTS Horn Cores No. 174 No. 175 Fore and aft diameter of base of horn cores 40.5 mm. Height of anterior prong measured from deepest point in cleft between two prongs (approximate) 53 Long diameter of anterior prong at base of porous surface 16 19 Transverse diameter of anterior prong at base of porous surface 14.6 17.9 Height of posterior prong measured from deepest point in cleft between two prongs 50 . 7 Long diameter of posterior prong at base of porous surface 15. 7 Transverse diameter of posterior prong at base of porous surface 13 .1

Right Ramus of Mandible No. 176 Length from anterior border of alveolus for P2 to posterior border of alveolus for M3 54.5 Anteroposterior diameter of M3 (approximate) 17.4 Greatest transverse diameter of M3 (approximate) 6 .2 Depth of ramus at posterior end of MJ, measured normal to inferior border 23.2 Thickness of ramus below anterior lobe of MJ 10.4 Transverse diameter of condyle 14.4

No complete vertebral column has been obtained, but individual segments are available from the cervical, thoracic and lumbar regions. Cervical vertebrae.- A single vertebra, namely the fifth, of this series occurs in the collection and is tentatively referred to T. (.?) conklingi. This specimen, No. 191, resembles the comparable element in dntilocapra and differs from that of Odocoileus in the elongation of the body and in the development of the transverse process. In No. 191, as in the existing pronghorn, the transverse process is somewhat plate-like and arises at the juncture of the posterior border of the inferior lamella and the outer posterior margin of the shelf extending outward from the side of the centrum. In the deer, on the other hand, the process is pointed, directed distinctly backward, and arises above the backward con­ tinuation of the border of the inferior lamella. In No. 191 the process does not project backward quite as far as in dntilocapra. The elongation of the vertebra is expressed also by the length of the vertebrarterial canal. In the deer this canal is shorter and likewise larger than in antilocaprids. The posterior opening of the canal in the vertebra from Shelter Cave is situated at a point farther in front of the posterior border of the neural canal than in dntilocapra. The lower end of the inferior lamella is recurved inward. The ventral a keel of the centrum is well marked but the anterior end sinks into the Fig. 2. Tetrameryx (?) conic, distal views; fig. 2b, 2bl, radi ventral surface before reaching the proximal epiphysis. The prezyga- Museum Collection. Quater 'ION No. 2 STOCK: QUATERNARY ANTELOPE REMAINS FROM NEW MEXICO 11 •

No. 174 No. 175 40.5 mm. ,eft between 53 16 19 rface 14.6 17.9 left between 50.7 15.7 urface 13 .1

1, I, No.176 1, r border of alveolus "I 54.5 17.4 6.2 to inferior border 23. 2 ''•1 10.4 "'· 14.4 11,

,;t )btained, but individual acic and lumbar regions. !ly the fifth, of this series a'

'( :rred to T. (?) conklingi. 1, 1le element in dntilocapra 1 ation of the body and in ~o. 191, as in the existing at plate-like and arises inferior lamella and the outward from the side d, the process is pointed, )Ve the backward con- b' In No. 191 the process 1ntilocapra. ed also by the length of al is shorter and likewise · opening of the canal at a point farther in nal than in dntilocapra. ed inward. The ventral a terior end sinks into the Fig. 2. Tetrameryx (?) conklingi, n. sp. Fig. 2a, 2al, humerus, No. 179, anterior and distal views; fig. 2b, 2bl, radius, No. 180, anterior and distal views; x 1.0. Los Angeles :piphysis. The prezyga- Museum Collection. Quaternary deposits, Shelter Cave, Organ Mts., New Mexico. • 12 Los ANGELES MusEuM PUBLICATION No. 2 STOCK: QUATERNARY

pophyses are narrow transversely and elongate anteroposteriorly. The postzygapophyses resemble those of Antilocapra in shape and in curvature. Lumbar Vertebrae

MEASUREMENTS Fifth Cervical Vertebra T. (?) conklingi Ant1locapra Length of centrum through mi< No. 191 No. M760 Transverse diameter across pos Greatest length of centrum 42.3mm. 58.5 Depth of centrum measured n Depth of proximal epiphysis measured normal to dorsal surface surface and across an teriot of centrum 11.4 18 .2 Length from anterior end of pre; Width of proximal epiphysis 12.7 19 posterior end of postzygap Width of distal epiphysis . 18.2 25.5 Transverse diameter across po Length from anterior end of prezygapophysis to posterior end of postzygapophysis . 41.9 56.5 Transverse width across prezygapophyses . 27.9 40.6 Sternum.- The first Transverse width across postzygapophyses . 30.6 38 fragment of the fourth, fused series is somewhat Thoracic vertebrae.-In depth of centrum the first thoracic vertebra, segment is relatively wi No. 192, resembles more closely Antilocapra than Odocoileus. The the bony margins adjac ventral surface is strongly keeled and at the anterior end are situated cartilages the sides of t two knob-like processes as in the pronghorn. The facet for the tubercle than in Antilocapra. of the rib is relatively large and faces in the main downwa~d, less forward than in Antilocapra. The prezygapophyses are relatively large but narrow transversely. Unfortunately the major portion of Sternum the neural spine is lacking. Length from anterior end o posterior end of mesoste1 Least width across middle of 1 MEASUREMENTS Least width across middle of i Least width across middle of 1 First Thoracic Vertebra T. (?) conk/ingi Antilocapra No.192 No. M760 Length of centrum along median line 19.9mm. 26.8 AJ Depth of centrum across distal epiphysis 12.6 19.2 Transverse width of centrum across posterior demi-facets 22.2 31.8 Scapula.-An incc Width across transverse processes 44 57.4 Tetrameryx (?) conklh Lumbar series.-The last three lumbar vertebrae in Tetrameryx (?) other than size the car conklingi resemble the corresponding segments in Antilocapra. As as in the pronghorn and indicated by the comparative measurements the individual vertebrae from the axillary horde are distinctly smaller than those of the latter type. The articulating the infraspinous area I surfaces of the postzygapophyses extend from the ventral to the dorsal Odocoileus the posterio: side and are enclosed by the recurved outer walls of the prezygapophy­ having considerable dt ses. Unfortunately the dorsal spines and the transverse processes coracoid process in No. are in large part broken away. The transverse processes may be between this process anc relatively broad. In Oois the notch appt ON No. 2 STOCK: QUATERNARY ANTELOPE REMAINS FROM NEW MEXICO 13

~ate anteroposteriorly. MEASUREMENTS 1capra in shape and in Fourth Fifth Sixth <:::> <:::> -~~ ' ~ ·~ ..... ~ ·~~ ' ~· Lumbar f/ertebrae ~~~ ...... ~ ' ,..-...... <::::) ~...., . ~~~ "'·~ ~~~ "'·~(\.,I ~ ::!~ ii:~~ '""'.'§~ ii:~~ ~~~ ~~~ ~~~ ~" E..." ~"

T. (?) conklingi Anttlocapra Length of centrum through middle 28.4 34.2 28.5 34.2 25.2 31.3 No. 191 No. M760 Transverse diameter across posterior face 20.3 26.6 22.3 29.4 27 34.5 42.3mm. 58.5 Depth of centrum measured normal to dorsal ce surface and across anterior face 13 20.4 12.4 20.3 12.2 19.2 11.4 18.2 Length from anterior end of prezygapophyses to 12.7 19 posterior end of postzygapophyses 38.5 49 37.7 50.9 37.8 46.4 18.2 25 .5 Transverse diameter across postzygapophyses 23.5 28.6 25.7 31.3 28.4 43 id 41.9 56 .5 27.9 40.6 Sternum.- The first three segments of the mesosternum and a 30.6 38 fragment of the fourth, No. 189, are available for comparison. The fused series is somewhat concave upward in its long axis. The anterior e first thoracic vertebra, segment is relatively wide transversely. Due to the development of than Odocoileus. The the bony margins adjacent to the areas of attachment of the costal riterior end are situated cartilages the sides of the segments are more conspicuous! y notched 'he facet for the tubercle than in Antilocapra. e main downward, less >ophyses are relatively MEASUREMENTS r the major portion of Sternum T. (?) conklingi Antilocapra No. 189 No. M760 Length from anterior end of mesosternal element No. to posterior end of mesosternal element No. 3 . 82.5mm. 115 Least width across middle of first mesosternal element . 15.2 18 Least width across middle of second mesosternal element 18.7 28 T. (?) conklingi Antilocapra Least width across middle of third mesosternal element . 21.2 31 No. 192 No. M760 19.9mm. 26.8 APPENDICULAR SKELETON 12.6 19.2 22.2 31.8 Scapula.-An incomplete scapula, No. 178, is referred to 44 57.4 Tetrameryx (?) conklingi. This specimen resembles in characters tebrae in Tetrameryx (.?) other than size the comparable element in Antilocapra. In No. 178 its in Antilocapra. As as in the pronghorn and in the mountain sheep the ridge which extends :he individual vertebrae from the axillary border obliquely across the outer surface, separating type. The articulating the infraspinous area from the neck, tends to become obscure. In the ventral to the dorsal Odocoileus the posterior edge of the scapula is continued by a ridge lls of the prezygapophy­ having considerable definition toward the base of the spine. The he transverse processes coracoid process in No. 178 is not so heavy as in Ovis and the notch rerse processes may be between this process and the glenoid cavity is deeper than in Antilocapra. In Ot1is the notch appears to be wider and shallower. 14 Los ANGELES MusEuM PUBLICATION No. 2 STOCK: QuATERNAR

MEASUREMENTS T.(?) conlilingi Anlilocapra Scapula No. 178 No. M760 Greatest anteroposterior diameter across glenoid cavity and coracoid process 28.9mm. 39.4 Greatest transverse diameter taken normal to anteroposterior diameter 23 28.7 Least anteroposterior diameter of neck . 16.1 21.6 Humerus.-The single specimen of this element available, No. 179, 1 figure 2a, a , is intermediate in size between the humerus of Capromeryx minor and that of the living Antilocapra americana. In the sum of its characters it resembles more closely the latter rather than the former. The deltoid crest is prominently developed as in the prong­ horn, more so than in Capromeryx. The shaft is relatively heavy. A nutrient foramen is present on the posterior surface of the shaft and is situated distinctly above the middle of the humerus. The distal articulating surface resembles that in Antilocapra and differs from that in Odocoileus in the presence of a more rounded keel for the groove at the proximal end of. the radius. When the humerus is viewed from the distal end, figure 2a1, the posterior walls of the olecranon fossa are seen to extend backward not so far as in Odocoileus, in which respect there is again a greater resemblance between the form from Shelter Cave and the modern pronghorn. As in the latter type the fossa is relatively w:der than in the deer. MEASUREMENTS T. (?) Antilo- Ca pro- Humerus conk/ingi capra meryx No. 179 No. M760 No. Z8571 Length measured from head to distal end 147.5mm. 183.8 95.9 Greatest anteroposterior diameter of proximal end 42 53.7 29.6 Greatest transverse diameter of proximal end 33.2 46.6 a24 Anteroposterior diameter of shaft at middle 20.3 22.8 11.8 Transverse diameter of shaft at middle 14.2 17.5 10 Greatest transverse diameter of distal end . 30 39.1 20.6 ,,. Greatest anteroposterior diameter of distal end 23.5 31.7 17.1 ~ I/'(~ a. approximate. ~ Radius.-A single complete radius and fragments of two additional specimens represent this element in the collection. The shaft, figure a 2b, is relatively heavy, more so than that in Antilocapra. At the proxi­ imal extremity the groove for the distal keel of the humerus is broad and shallow as in the latter genus, not so deeply incised as in Odocoileus. Fig. 3. Tetrameryx (?) conk At the distal extremity, figure 2b1, the keel separating the posterior anterior and lateral views; fig . end of the surface for the scaphoid from that for the lunar tends to be views; xl.O. Los Angeles J 10N No. 2 STOCK: QUATERNARY ANTELOPE REMAINS FROM NEW MEXICO 15

T.(?) conklingi Antilocapra No. 178 No. M760 and 28.9mm. 39 .4 :nor 23 28 .7 16.1 21.6 ,,, ~ nent available, No. 179, i" humerus of Capromeryx '• ricana. In the sum of latter rather than the eloped as in the prong­ tft is relatively heavy. or surface of the shaft of the humerus. The /1' I dntilocapra and differs . I ,, \ ire rounded keel for the '~ I When the humerus 1s I I or walls of the olecranon ; in Odocoileus, in which between the form from i, 1t in the latter type the ::,.

·. (?) Antilo- Ca pro- 1/c/ingi capra meryx '· 179 No. M760 No. U57l 7.5mm. 183.8 95 .9 2 53.7 29 .6 3.2 46.6 a24 0.3 22.8 11 .8 4.2 17.5 10 0 39.1 20 .6 3.5 31.7 17 . 1

;men ts of two additional ti on. The shaft, figure a a' ri/ocapra. At the proxi­ >f the humerus is broad incised as in Odocoileus. Fig. 3. Tetrameryx (?) conlclingi, n. sp. Fig. 3a, 3al anterior cannon bone, No. 185, ;eparating the posterior anterior and lateral views; fig. 3b, 3bl, posterior cannon bone, No. 187, anterior and lateral or the lunar tends to be views; xl.O. Los Angeles Museum Collection. Quaternary deposits, Shelter Cave, Organ Mts., New Mexico. STOCK: QuATERNA 16 Los ANGELES MusEuM PuBLICATION No. 2 rounded or flattened transversely as in the pronghorn and is not so sharply defined as in the deer. _The posterior end of this keel is carried inward farther in the deer than in the pronghorn. In the radii from Anterior Cannon Bone Shelter Cave the position of the posterior end is more as in Antilocapra. Greatest length In the former type as in the latter the distal extremity of the ulna Greatest transverse diameter truncates obliquely the outer posterior end of the surface for the cunei­ Anteroposterior diameter of form. In Odocoileus, on the other hand, the ulna touches but does not Transverse width of shaft at Anteroposterior diameter of truncate this surface. Transverse width across dist Judging from the remnant of the ulna still adhering to the distal Anteroposterior diameter of end of the radius, the shaft of this element was apparently som~what Posterior cannon more reduced than in existing types. cannon bone of the hi In Tetrameryx (?) conklingi the ratio of length of humerus to length locapra and may be on of radius may be expressed as 1 :l.05, whereas in Antilocapra americana8 ble element in the Pl 1 this ratio is 1 :l.18. In other words, the radius of the former species 3b, b , is relatively hei is slightly shorter relative to the length of the humerus than in the the anteroposterior di pronghorn. The two elements may not, however, represent the same the pronghorn and in 1 individual. groove of the anterio1 distinctly shallower ti shallow than in Antil MEASUREMENTS is large and conspicuo Radius T. (?) conklingi Anti/ocapra upper end of the shaJ No.180 No. M760 cuboid, navicular-cub 156 mm. 217 Greatest length are well defined. Th Width of proximal end 28.8 37.2 Anteroposterior diameter of proximal end 16.3 extensive in No. 187 Transverse width of shaft at middle . 16.4 20.5 is made to Antilocap Anteroposterior diameter of shaft at middle 9.6 10.6 deeply pitted. Transverse diameter of distal end 26.7* 34.2 Anteroposterior diameter of distal end 20.6 24.3 •l\te-asurcment includes that of distal end of ulna. Posterior Cannon BG Anterior cannon bone.-This element, represented by two specimens in the collection, Nos. 184, 185, is noticeably smaller than that of Greatest length Antilocapra amerirana while the shaft is relatively heavier. The Greatest transverse diamet Anteroposterior diameter c comparable element in Capromeryx while only a trifle shorter is decidedly Transverse width of shaft more slender. The longitudinal groove of the anterior face, figure 3a, Anteroposterior diameter c is faintly marked. The groove on the posterior face is broad and is Transverse width across di clearly defined by the lateral walls along the upper two-thirds of the Anteroposterior diameter c shaft. In deepness of pit on the outer wall of the distal trochlea T. (?) conklingi appears to resemble more closely the pronghorn than Odocoileus. 'Gregory records the ratio for this species as 1:1.23 Gregory, W. K., Ann. N. Y. Acad. Sci., vol. 22, pl. 34, 1912. rION No. 2 STOCK: QUATERNARY ANTELOPE REMAINS FROM NEW MEXICO 17

•ronghorn and is not so MEASUREMENTS :nd of this keel is carried T. (?) T. (?) Antilo- Capro- 10rn. In the radii from Anterior Cannon Bone conklingi conklingi capra meryx s more as in Antilocapra. No. 185 No. 181 No. M760 No. Z8667 Greatestlength . 153.6mm. 147.5 218.4 146.7 .I extremity of the ulna Greatest transverse diameter of proximal end 26. 6 23 28.3 15.4 he surface for the cunei­ Anteroposterior diameter of proximal end . 17. 5 15. 5 20.6 11.8 lna touches but does not Transverse width of shaft at middle . 14. 7 14.4 15.6 10.3 Anteroposterior diameter of shaft at middle 12 .1 11. 5 13. l 9.4 Transverse width across distal trochleae 23 .4 23. 5 28 15.6 II adhering to the distal Anteroposterior diameter of distal trochleae 16.6 15 .6 20.7 11.7 as apparently somewhat Posterior cannon bone.-As indicated by the measurements the cannon bone of the hind limb is distinctly shorter than that of Anti­ th of humerus to length locapra and may be only slightly longer than specimens of the compara­ ri Antilocapra americana3 ble element in the Pleistocene Capromeryx minor.. The shaft, figure us of the former species 3b, b1, is relatively heavy. In No. 187 the transverse diameter exceeds ie humerus than in the the anteroposterior diameter at the middle of the shaft, whereas in :ver, represent the same the pronghorn and in Capromeryx the reverse is true. The longitudinal groove of the anterior face is clearly marked, although the furrow is distinctly shallower than in Odocoileus. This groove is likewise more shallow than in Antilocapra. The foramen at the base of the groove is large and conspicuous. Two nutrient foramina are present at the T. (?) conklingi Antilocapra upper end of the shaft and on the posterior face. The facets for the No.180 No. M760 156 mm. 217 cuboid, navicular-cuboid, and for the external and middle cuneiforms 28.8 37.2 are well defined. The interarticular area of the proximal end is more 16.3 extensive in No. 187 than in Ovis, in which respect a closer approach 16.4 20.5 is made to Antilocapra. The lateral walls of the distal trochlea are 9.6 10.6 26.7* 34.2 deeply pitted. MEASUREMENTS 20.6 24.3 T. (?) Antilo- Capro- Posterior Cannon Bone conklingi capra meryx sented by two specimens No. 187 No. M760 No. Z8706 y smaller than that of Greatest length 165. 6mm. 229 161. 7 elatively heavier. The Greatest transverse diameter of proximal end 22.2 25.7 16.7 trifle shorter is decidedly Anteroposterior diameter of proximal end . 21.9 28.6 17.9 Transverse width of shaft at middle 14.2 14.9 10.4 anterior face, figure 3a, Anteroposterior diameter of shaft at middle 12.4 16 .4 11.6 ior face is broad and is Transverse width across distal trochleae 24.4 28.3 18.4 upper two-thirds of the Anteroposterior diameter of distal trochleae 17.2 21.2 13.8 of the distal trochlea ely the pronghorn than

:regory, W. K., Ann. N. Y. Acad. 18 Los ANGELES MusEUM PUBLICATION No. 2

CONCLUSIONS While the skull of Tetrameryx (?) conklingi is as yet but imper­ fectly known, the characters displayed by the horn cores and more particularly by the associated lower jaw and skeletal material, point strongly to the presence of a family bond with the Antilocapridae. The relationship of Tetrameryx shuleri to the antilocaprid group has been established by R. S. Lull. The peculiar character of the horn cores in the form from Shelter Cave as in T. shuleri obviates the possi­ bility of a close relationship with existing Antilocapra or with the Pleistocene Capromeryx. It is conceivable that the former species were derived from a Sphenophalos-like ancestor of the . In the light of the vari·ation in structure of horn core of the modern pronghorn, some of the more striking characters which distinguish T. (?) conklingi from T. shuleri and which may be regarded as of generic value are attributed to a difference in age and sex. The material from Shelter Cave is therefore assigned, at least tentatively, to the genus Tetrameryx. The difference in the proportions of the anterior horn core and the consistently small size of the materials referred to the type from New Mexico serve to distinguish the form from T. shuleri. Pre­ sumably T. (.?) conklingi is also smaller than Neomeryx. The heavier limb elements in T.(.?) conklingi suggest an antelope less fleet-footed than the modern pronghorn. The comparatively heavy metapodials offer a striking contrast to the slender elements in the light-limbed Capromeryx.