The Yellow River Elephant (Stratigraphy & History of Research) ? The Yellow River Elephant (Stratigraphy
Post on 26-Jun-2018
The Yellow River Elephant (Stratigraphy & History of Research)
The Yellow River Elephant Research Team
Translated By Will DownsDepartment of GeologyBilby Research Center
Northern Arizona UniversityJune, 1990
A Review of Research Conducted Upon Stegodontine Elephants of China
Prior to the establishment of the People's Republic, China sank into semi-feudalism andwas subjected to partial colonization. As with the other scientific disciplines, the research ofpaleontology was dominated by foreigners, as was research upon Stegodon prior to the 1930s.Several species of Stegodon were erected after research was conducted upon "dragon bones"derived from traditional Chinese pharmacies1 where precise locality and stratigraphic informationwere lacking. There were also workers who made several fossil excavations but these fossils werepredominantly transported outside of China for study.2 Endemic research by Chinesepaleontologists was undertaken only subsequent to 1930.
C.C. Young was the first Chinese paleontologist to undertake research upon Stegodon,describing Stegodon ysheensis Young 1935 from the earliest Pliocene of Yushe, Shanxi Province.After describing the new stegodontine species S. pre-orientalis from Babu, Guangxi Province, in1938, Young produced the first taxonomic synthesis of Stegodon in China. In this work hesynonymized S. insignis described by Koken (1885) and Schlosser (1903), S. orientalis describedby Hopwood (1935), and S . cf. orientalis described by Teilhard and Young (1937) with his newlyerected taxon S. pre-orientalis. He also acknowledged five other Stegodon species:3:
S officinalis Hopwood 1935
S. licenti Teilhard and Trassaert 1937
S. zdanskyi Hopwood 1935
S. ysheensis Young 1935
S. orientalis Owen 1870
1 The Englishman Richard Owen in 1870 published upon Stegodon after undertaking research on material that was derivedfrom a traditional Chinese pharmacy in Shanghai. At that time he erected the two species Stegodon orientalis and S.sinensis. The German E. Koken in 1885 purchased a set of specimens from a Chinese pharmacy after which three morespecies were described: the first being possibly derived from the upper reaches of the Yellow River in the western section ofGansu Province, (S. cliftii Falconer and Cautley was later synonymized with S. sinensis Owen 1870 and S. sinensis Baauns1883); the second species may have been derived from Yunnan or Sichuan provinces (S. aff. bombifrons Falconer andCautley 1846); and the third may also have been derived from Yunnan (S. signis Falconer and Cautley 1846 which wassynonymized with S. orientalis Owen 1870). The Englishman A.T. Hopwood in 1935 described two species with vague stratigraphic and locality data: S. zdanskyi andS. officinalis. The material was derived from a traditional Chinese pharmacy in Shanghai.2 From 1920-1921, the American Walter Granger conducted large-scale excavations of Stegodon orientalis at Yanjinggou,Wu County, Sichuan Province. The characteristics of the associated faunal complex confirms the consistency with materialdescribed from Europe. This was the first locality in China to produce Stegodon that was associated with accuratestratigraphic data. However due to the demonic, sycophantic, foreign reactionary government ruling China at that time, allthis material was pirated to America. The American Henry Fairfield Osborn (1929) recognized a new subspecies from theSichuan, Yanjinggou fauna: S. orientalis grangeri.The French P.T. de Chardin and M. Trassaert in 1937 described an extremely primitive species, S. licenti, that wasconfirmed to be produced from Yushe Zone I in southeastern Shanxi Province. He was later at the point of synonymizing S.ysheensis and S. officinalis with S. zdanskyi.3Osborn's 1942 monograph Proboscidea did not follow the synthesis of Chinese Stegodon described above, butpromoted instead the recognition of only S. sinensis, S. orientalis, S. orientalis grangeri, S. ysheensis, S.officinalis, and S. zdanskyi. Teilhard and Leroy (1940) later advanced the Chinese Stegodon taxonomic list byrecognizing only three taxa: S. licenti, S. orientalis (including S. orientalis grangeri, S. pre-orientalis, and S.sinensis), and S. zdanskyi (including S. officinalis and S. yshensis).
Under the leadership of the Chinese Communist Party and Chairman Mao, the shackles ofsemicolonization were shattered, liberating the entire nation, and liberating, in the same manner, theresearch endeavors undertaken by Chinese scientists. Chinese biostratigraphic workers began tojourney upon their own road of socialist service to broadly expand China's biostratigraphicendeavors.
From 1950, and particularly since the proletariat cultural revolution, extensive discoveries ofStegodon were made by workers, peasants, and the military. In 1962, Minchen Chow and RenjieZhai described the large S. zhaotongensis from Yunnan Province and the large and derived S. chiaifrom Shanxi Province. They moreover recognized S. ysheensis to be independent of S. zdanskyi.In 1973 Houyi Liu, Yingjun Tang, and Yuzhu You described S. primitivum, a large and primitiveform from the Banguo Basin of Yuanmou, Yunnan Province in South China. Another species,S. yuanmouensis was published at the same time.
In 1974, Minchen Chow and Yuping Zhang, in a final analysis, published The FossilProboscidea of China in which they recognized the following seven species of Stegodon:
S. orientalis Owen 1870
S. zdanskyi Hopwood 1935
S. ysheensis Young 1935
S. licenti Teilhard and Trassaert 1937
S. pre-orientalis Young 1938
S. zhaotongensis Chow and Zhai 1962
S. chiai Chow and Zhai 1962
In addition to the species listed above, there should be added the two aforementioned taxafrom Yunnan and the Yellow River Elephant of this text to increase the total of Stegodon speciesfound in China to ten. Consequently, China possesses the most taxonomically diverse assemblageof Stegodon in the world.
Based upon the research of Chinese paleontologists, Chow and Zhang reconfirmed thepresence of S. ysheensis and S. pre-orientalis, nomenclature that was expunged by foreignworkers. In addition they revised the Chinese nomenclature for S. zdanskyi, such that the Chinesecharacters formerly transliterated to represent the name Zdansky were replaced by the Chinesecharacters for Shanxi Province. This paper recognizes the necessity for these emendations.
Research upon these ten species suggests that seven of the taxonomic names erected byChinese paleontologists are associated with precise stratigraphic and locality data, while the threetaxonomic names erected by foreign workers are associated with vague provenance. This hasresulted in some confusion. Within the 80 years prior to liberation, from 1870-1949, only fivespecies were erected, while in contrast, during the past two to three years of the CulturalRevolution, three new taxa were discovered. In addition there have been no discoveries ofskeletons equivalent to that of the Yellow River Elephant in the world to date. All of these pointsstrongly confirm the magnificent propriety of Chairman Mao's revolutionary line. The discovery ofthe Yellow River Elephant is a fruitful and substantial product of the great proletariat CulturalRevolution. This will provide a strong counterattack to the foreign reactionaries within the countrywho oppose the proletariat Cultural Revolution.
Figure 1. Geographic location of fossil localities
Geologic Age of the Sediments Bearing the Yellow River Elephant
The Yellow River Elephant was produced from the Muzhuagou Formation under thejurisdiction of the Mu Tribal Production Brigade of the Tianyao Unit in Banjiao Commune, HeshuiCounty, Gansu Province. Its locality lies at East Longitude 108, and North Lattitude 35 50(Figure 1). Topographically it lies in the globally reknowned Longdong Loess Plateau (refer to theYellow River Elephant fossil locality text plate). The specimen was derived from the lower gravelsand sandy clay deposits of the plateau. Complete exposures of this set of deposits occur fromLocality 73118 to Gouyuli in the vicinity of Banjiao where 30-40 meters of thickness is visible. Anovereview of the cross-section containing the Yellow River Elephant (73118), in addition to thecontemporaneous localities at Hengou (73121) and Zhaojiawa (73120) is provided below.
1. Section at Locality 73118
The approximately 102 meter section (including the upper section's reddish soil and loess)is located along the right bank of the Malianhe River approximately one-half kilometer south of theMu Tribal Production Brigade. From top to bottom the section is:
(14) Reddish clay and loess (Q2-3).... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 m(13) Tan-yellow sandy clay...................................................................24 m(12) Silts grading to yellow ferromanganese mottling....................................0.5 m(11) Yellow planar-bedded fine sands......................................................1.5 m(10) Tan-yellow sandy soil and sandy clay.................................................14 m
Figure 2. Cross-section of the Yellow River Elephant locality 73118
(9) Light tan cross-bedded coarse sands .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.3 m(8) Sandy gravels, partially consolidated, gravel elements predominantly as purple-red and
grey-blue slates. Grades into limestones, sandstones, and calcareous concretions. Subangular andrelatively well sorted...................................................................................0.5 m
(7) Tan-yellow sandy clays, massive, and partially grades to sandy gravel lens bodies.Contains Struthio anderssoni and Equus sp.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 m
(6) Tan-yellow sandy soil..................................................................... 3 m(5) Thinly bedded fine sands and sandy clays.......................................... 12.3 m(4) Monoclinal sands and sandy soils bearing Prosiphneus intermedius and
Proboscidipparion sp... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.8 m(3) Orange-yellow, gray-green clays grading to sandy lens bodies....................1.5 m(2) Grey-white coarse cross-bedded sands .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.0 m(1) Gravels grading to coarse sand lens bodies. Partially consolidated gravels are
composed of silicates, limestones, calcareous concretions, quartz sands, slates, sandstones, andothers elements. Limestones constitute 70%, slates 20%, and the remainder 10%. Most gravels aresubangular, relatively well sorted, with 30% of the pebble's diameter below one cm, 60% up toapproximately 3-4 cm, and approximately 10% up to 10 cm and above........................6.4 m
~~~~~~~~~~~~~~~Unconformity~~~~~~~~~~~~~~~Base: Cretaceous, thinly bedded purplish to gray blue silts and slates.
Stegodon huanghoensis sp. nov., Gazella sp., Camelus cf. knoblochi, and others, are allproduced from within units (1)-(3)
2. Cross-section at Locality 37121
The section (Figure 3) is approximately 48 m thick, and is present in an arroyo off the rightbank of the Malianhe River on the west side of Banjiao Commune. From top to bottom it isdisplayed as:
(4) Reddish soil and Loess (Q2-3).... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 m(3) Tan-reddish sandy soil with basal gravels..............................................10 m(2) Tan reddish sandy clays, base with planar-bedded gravel zones, partially well
consolidated and weathers to form "resistent protrusive" forms. Contains Archidiskodon sp.,Proboscidipparion sp., Gazella sp., and others.....................................................10 m
(1) Upper section as tan reddish sandy soils, lower section as gravels. Partially wellconsolidated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 m
~~~~~~~~~~~~~~~Unconformity~~~~~~~~~~~~~~~Base: Cretaceous, purple, gray-blue slates.
Figure 3 Cross-section of Fossil Locality 73120 at Hengou
3. Section at Locality 73120
The section (Figure 4) is approximately 57 m thick and located one-half kilometer northeastof Banjiao Commune:
Upper section: Secondarily deposited loess and reddish soils............................30 mMiddle section: Tan-reddish sandy soils and gravels, base as gravels with calcareous
cementation. Contains Archidiskodon planifrons and Equus sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mLower section: Tan-reddish sandy clays and gravels, partially well consolidated, and forms
protrusions after weathering. Contains Gazella sp., Proboscidipparion sp., Equus sp.,
Archidiskodon planifrons, Mimomys banchiaonicus sp. nov., Struthio anderssoni, and Trionyx sp.Observable thickness.................................................................................... 2 m
The Yellow River Elephant was entombed at the base of the fluviolacustrine reddish soils.Its stratigraphic age may be as early as the "Hipparion Red Clay" or as late as the NihewanFormation. In addition to undertaking a study of Localities 73118, 73120, and 73121, otherlocalities such as Qingyang and Zhenyuan will be emphasized for local study. Collections havebeen made in cross-sections relating to the sediments of the Yellow River Elephant in order toclarify the age problem and advance the determination of relationships between the sedimentscontaining the Yellow River Elephant and those above and beneath the site. This supplementalmaterial has undergone preliminary diagnosis and comparison confirming the conclusions of formerworkers who believed the chronologic subdivision of the mammalian faunas in the Qingyang regionto lie between the latest Pliocene to the earliest Pleistocene. Three fossiliferous units have beenrecognized:
Figure 4. Cross-section at Banjiao Locality 73120
(I) Qingyang Jiazichuan Unit
Lithology as tan-red silty mudstones. Exposures at localities including Jiaozichuan,Qingyang; Niujiaogou, Zhenyuan; and Dashanmen, Laocheng, Heshui. These localities all producetaxa typical to a Hipparion fauna, including: Prosiphneus licenti, Ictitherium wongii, I. hyaenoides,Hyaena variabilis, Metailurus minor, Hipparion hippidiodus, Chilotherium sp., Chleuastochoerusstehlini, Palaeotragus sp., Samotherium cf. neumayri, Gazella dorcadoides, Protoryx planifrons,Prosinotragus tenuicornis, and others. These represent a contemporaneous regional fauna withinthe earliest Cenozoic stratigraphic unit of the region.
(II) Qingyang Bajiazui Unit
The publication Quaternary Stratigraphy of the Longdong Loess Region of NorthernShaanxi Province by Yongyan Wang and Xiangzhao Bi describes this unit as fluviolacustrine sandsand sandy soils exposed at Bajiajuzui, Qingyang. Mammalian fossils identified from this unitinclude: Canis chihliensis, Cuon cf. dubius, Vulpes cf. corsao, Meles cf. chiai, Hyaena cf.licenti,Megantereon (sp. nov.), Epimachairodus (sp. nov.), Felis sp., Proboscidipparion cf. sinensis,Equus sanmeniensis, Sus sp., Cervus (cf. Euctenoceros) sp., Gazella cf. sinensis, Bisonpalaeosinensis, and others. Wang and Bi suggested that numerous Hipparion faunal elements hadhere either become extinct or migrated south. This represents a densely forested grassland faunadominated by wolves, foxes, gazelle, horses, and deer, displaying a northern mammalian faunalcomplexion. Xiangzhao Bi believed the age of this fauna to predate that of Nihewan.
(III) Yellow River Elephant-bearing sediments at Heshui, Qingyang
Lithology as gravels, sand, and silty clays. A general perspective of the taxa found hereindicates the appearance of Quaternary elements such as Equus sp., Archidiskodon planifrons, andCamelus cf. knoblochi. Also recovered are transitional taxa between the Pliocene and EarliestPleistocene including Proboscidipparion sp., Prosiphneus intermedius, Mimomys banchiaonicussp. nov., and others. Both extant taxa and archaic taxa are rare. This condition, where a fauna isdominated by the appearance of new taxa, generally indicates the inception of a new phase.Consequently, the Yellow River Elephant-bearing sediments clearly manifest Early Pleistocenecharacteristics.
In summary of the aforementioned, Items I, II, and III represent three geologic units: theage of I represents the earliest and lowest stratigraphic position. The age of II is the latest andhighest stratigraphic position. The age of III appears to lie between I and II. That is to say that theYellow River Elephant Fauna differs greatly from both that at Bajiazui and at Jiazichuan. The lackof Carnivora suggests a sparsely forested grassland for the environment of the Yellow RiverElephant. Proboscidea and rodents not discovered at Bajiazui indicate a densely forested grassland.Jiaozichuan belonged to a grassland habitat. These conditions clearly indicate that the age of theYellow River Elephant deposits cannot be equivalent to Bajiazui, Jiaozichuan, or the others. Thelower boundary of these sediments should equate with the Hipparion Red Clays at Jiaozichuan.Their relationship may be observed in the following table.
Q3 Loess Loess Loess
Pleistocene Q2 Reddish soil Reddish soil Reddish soil
sedimentsYellow RiverElephant seds.
The table above depicts the sequence and temporal relationships of the several principalQuaternary fossiliferous deposits in the Qingyang region. Following is a brief discussionconcerning the age and correlation of the Yellow River Elephant sediments to the other EarlyPleistocene sediments of North China.
Although it is not possible to recognize a genuine portrait of the mammalian fauna fromLocality 73118 (due to the sparse taxonomic diversity and amount of incomplete fossil material,with the exception of the elephant), nevertheless, the locality and stratigraphic position areabsolutely determinable. Approximately 50% of the taxa appearing at this locality are typical of theEarly Pleistocene faunas in North China, including Equus, Proboscidipparion, Prosiphneusintermedius, and others. Additionally, the presence of Archidiskodon is particularly noteworthy(Plate 12, Fig. 2), for it appears to be somewhat more primitive than the specimens from Yushe,Shanxi Province, but approaches the representative taxa from the early stages in India.Furthermore, Mimomys is an indicative taxon for the Early Pleistocene in Europe. These evenmore clearly indicate the Yellow River Elephant fauna is of a nature between the end of the Tertiaryand beginning of the Quaternary.
Based upon the current material and its comparison to the well-known Nihewan Fauna,among the eleven species found within the Yellow River Elephant sediments, at least five(approximately 50%) do not appear at Nihewan (Table 3). As aforementioned, Archidiskodonplanifrons, Stegodon, Prosiphneus intermedius, and other elements occur here, while from anotheraspect, the extant taxa that appear in the Nihewan Fauna are rare in the Yellow River Elephantsediments. From the perspective of these conditions, the age of the Yellow River Elephantsediments appears to be slightly older than those at Nihewan. In addition, Stegodon huanghoensisfrom Locality 73118 represents a relatively more primitive species than those known from otherlocalities from the Quaternary of North China, which may also confirm the hypothesis proposedhere. In this manner, North China Early Pleistocene deposits may be postulated to be arranged asin Table 2.
North China South AsiaQingyang
Late Locality 18Wucheng
seds.Pinjor Kali Glagah
Pleistocene Early NihewanFm.
With regard to the absolute age of the Yellow River Elephant sediments, they areprovisionally recognized here as 2 Ma. This date is derived from the correlation to the stratigraphicpositions of the Lantian hominid sites and the (Nixiwa?) hominid site of Java.
The two hominid-producing localities of Java include the Early Djetis units and the LaterTrinil units. The fauna from the Djetis units are relatively consistent with the Gongwangling Faunaof Lantian such as Homo erectus and the first appearance of modern taxa (Panthera, Tapirus, etc.),in addition to the derived genus Leptobos. The Trinil Fauna is nearly identical to Locality 1 of
Choukoutien. The former locality is recognized as being 1.75 Ma, while the later is .75 Ma.Postulated in this manner, the Yellow River Elephant sediments are regarded as Early Pleistocene,with an absolute date exceeding that of Djetis and Gongwangling, that being 2-2.5 Ma. Naturally,confirmation of these dates must wait for the results of more precise studies.
Prosiphneus intermedius ----------- -----------Mimomys banchiaonicussp. nov
Camelus cf. knoblochi ----------- -----------Gazella sp. ----------- ----------- ----------- ----------- -----------Proboscidipparion sp. ----------- ----------- ----------- ----------- -----------Equus sp. ----------- ----------- ----------- ----------- ----------- -----------Stegodon huanghoensis sp.nov.
Archidiskodon sp. -----------A. planifrons -----------Struthio anderssoni -----------Trionyx sp. -----------
The Yellow River Elephant
Shaohua Zheng(Institute of Vertebrate Paleontology, Paleoanthropology
I Vertebrate Fauna Associated with the Yellow River Elephant
Several taxa were recovered during the process of excavating the Yellow River Elephant.These findings occurred upon investigating the stratigraphic distribution and upper and lowerrelationships of the fossiliferous sediments. Localities were discovered in the same deposits as theYellow River Elephant at Banchiao and Hengou.
Locality numbers for these sites are: Yellow River Elephant Locality 73118; ZhaojiawaLocality 73120 at Banchiao Commune; and Hengou Locality 73121 at Banchiao Commune.
The specimens recovered from these localities are not extensive and are rather fragmentarypermitting only a general preliminary diagnosis. In order to facilitate narration, the descriptions areconducted systematically rather than in sequential order of locality.
Prosiphneus intermedius Teilhard and Young
(Plate XII, Fig. 6)
The specimen consists of a section of left mandible bearing an M1, the anterior half of anM2, and the central shaft of the incisor. It is derived from Locality 73118 (specimen numberV. 4754).
The specimen is moderately worn. The labial side of the occlusal surface displaysreentrants opened half-way to the base of the crown. The lingual side of the dentition displaysreentrants open to the base of the crown, with only an extremely small section not opened. TheM1 possesses two labial reentrants and three lingual reentrant folds. The M1 is 6.4 mm high, 2.1mm broad, 3.0 mm long, and the diameter of the incisor is 1.5 x 1.7 mm.
Mimomys banchiaonicus sp. nov.
(Plate XII, Fig. 9)
Material: One left M1 of an aged individual from Locality 73120 (specimen V. 4755).
Description: This is a particularly large individual with two roots, the anterior beinglarge and the posterior small. Abundant cementum lies within the reentrant folds. In addition tothe anterior and posterior loops are three triangles, all of which have undergone wear (Fig. 9.).There is a relatively broad dentine confluence between the first pair of triangles which are not verytightly closed off. The second pair of triangles are tightly closed off. The structure of the anteriorloop is complex with the prism fold, islet fold, Mimomys kante, and fourth lingual reentrant allpenetrating the entire crown. The overall condition is that labial salient angles and reentrant foldsare more narrow and deep than on the lingual side. The morphology of the crown is nearlytriangular, being narrow anteriorly and broad posteriorly. Its length is 4.0 mm and breadth 2.0mm.
Discussion and comparison: Among the material recently discovered in EasternEurope and within the general description of eight European species provided by A.C. Hinton(1926), there is no taxon larger than the Banchiao specimen. The only taxon that approaches thisspecies is the Pliocene microtine M. pliocaenicus Major; however, this latter species has a thinnerand more elongated crown, the occlusal surface is not triangular, the salient angles are rather
projected, and it is a smaller individual. M. orientalis Young (1935), discovered previously inChina, is a moderate-sized juvenile with a more complicated anterior loop than the specimendescribed here; hence, it is obviously not the same species. Consequently, this specimenconstitutes a new taxon. The etymology of Mimomys banchiaonicus sp. nov. is derived fromBanchiao Commune, from where it was produced.
Figure 9. Occlusal view of Mimomys banchiaonicus sp. nov.
Camelus cf . knoblochi Brandt
(Plate XII, Fig. 1)
A left metatarsus is present with approximately one-fifth of the distal end missing.Locality 73118 (V. 4756).
The total length of the element is 420 mm. The proximal articular surface is 46 mmanteroposteriorly and 64.5 mm wide. The medial shaft is 44 mm anteroposteriorly and 38 mm inwidth. The measurements indicate it is larger than the extant Camelus, smaller than Paracamelusgigas but approaches Camelus knoblochi.
(Plate XII, Fig. 3)
Material consists of two left and one right horn core from Locality 73118(V. 4757).
The best preserved specimen is V. 4747 (1). A portion of the parietal is connectedto the base of the horn core. The element curves posteriorly, with its apex rotated slightlymedially, and is elliptical in cross-section. Vertical striations are present on its surface that aremore well developed on the anterior and posterior sides than on the lateral sides, and areparticularly noticeable on the anterior side. The posterior orbital foramen is round.
Measurements: V. 4751 (1) (mm)
Horn core length 124Circumference at base 80Diameter at base 29 x 24
(Plate XII, 4,5)
Material consists of six isolated upper teeth: one left P2 and one right M3 from Locality73120; a DP3 or DP4 from locality 73118; and a DP2 from Locality 73121 (V4758).
The interior walls of the pre- and postfossetes display an extensive range ofplication. The protocone is long and oblately extended with an average length ranging between 9.5and 8.0 mm and average width of 4.0 mm.
(Plate XII, Fig. 8)
One left P2 and one left P3 (?) from Locality 73120 in addition to the proximal endof one right femur 73118. (V4759).
The P2 has a length of 32 mm and width of 25 mm; the P3 (?) has a length of32 mm and width of 28 mm. The P3 (?) displays plications on the interior walls of the pre- andpostfossets that are well developed but not extensive in range. The sustained presence of ahypoconulid is a particular reflection of its primitive nature. This is quite distinct from the P2which may belong to a different individual. The characteristics reflected on the femur approachmodern Equus and differ completely from the robust nature of Hipparion.
Archidiskodon planifrons Falconer and Cautley
(Plate XII, Fig. 2)
Material consists of a well-preserved right M3 from Locality 73120 (V4760).
The first two anterior lophs have just begun to be worn. This molar maintains eleven toothplates with an extremely well-developed anterior accessory wall on the first loph. The lamellafrequency is relatively low, being 3.5 anteriorly and 4 posteriorly. Each plate is generally palmshaped. The first anterior tooth plates have just undergone wear and display several irregularenamel rings. After more advanced wear these rings unite to form a single unit that is slightlyexpanded at its center. A central cusp is projected at the center of all the tooth plates, which isparticularly noticeable on several of the anterior plates. The entire crown is filled with cementum.The length of the crown is 316 mm. The width and height of each plate is displayed in thefollowing table (measurements in millimeters):
Plate# 1 2 3 4 5 6 7 8 9 10 11
Width 98 106 109 110 109 106 104 98 83 68 54Height 86 108 134 134 130 119 112 104 101 86 74
One right deciduous molar is present from Locality 73120 (V4761).
Wear has just commenced on the anterolingual side. It maintains four lophs.Posteriorly there is an isolated mammilla that is structured like a talonid. The accessory wall on theanterior end is well developed. The deciduous tooth is 26 mm in length. The data on the toothplates is as follows (measurements in mm):
Plate # 1 2 3 4Width 11.5 18 17 10Height 19 20 16.5 14.5
Two fragments of eggshell are present from Locality 73118 (V4762). The surfacetexture of the shell is smooth. It has a thickness of 2.3-2.5 mm.
Five fragments of costal plates are present from Locality 73120 (V4763) with pittedornamentation and irregular morphology.