ΐῒ῏ῑῐ ῍῎῍῎ῌThe Quaternary Research.1 - p. +/3 +1, June ,**2 Early Pleistocene soricomorphs and lagomorphs from the Xiaochangliang site in the Nihewan Basin, Hebei, Northern China Yingqi Zhang*+, and Yoshinari Kawamura* ,a This paper systematically describes soricomorph and lagomorph remains collected by a screen-washing procedure from the sediments of the Xiaochangliang site with the age of+4-0 Ma. The soricomorph remains described are assigned to the tribe Soricini in the subfamily Soricinae of the family Soricidae, on the basis of the detailed dental morphology. Among the genera of the tribe known from the Pliocene and Pleistocene of Asia,Sorex has morphological characters well coincident with those of the remains. Owing to their incompletion, the specific determination can not be done, and thus they are assigned merely toSorex sp. All the lagomorph remains belong to the family Ochotonidae. The family comprises two genera,Ochotona and Ochotonoi- des, in the Pliocene and Pleistocene of China. The remains are easily divided into a smaller and larger forms by their striking di# erence in size. The dental morphology and size of the smaller form indicate its allocation toOchotona. The smaller form is compared with many species ofOchotona known from the Pliocene and Pleistocene as well as the present day of China, and is assigned to the extinct species,O. youngi. The larger form is, however, assigned merely toOchotona or Ochotonoides sp., because of its limited specimens with poor preservation. Keywords : soricomorph, lagomorph, systematics, Early Pleistocene, Xiaochangliang site, Nihewan Basin, China knowledge on small mammals from the layer I. Introduction had been quite limited, until we washed the The Xiaochangliang site is one of the most sediments stratigraphically equivalent to the important archaeological sites of Early Pleisto- layer with fine-mesh screens in,**/ . Our cene age in China, and is situated in the Nihe- screen-washing successfully produced a large wan Basin about+/* km west o north o west of number of small mammal remains which in- Beijing (see Fig.+ of Zhanget al., ,**2 ). The cluded +* forms identifiable at the generic or artifact layer of the site is intercalated in flu- specific level (Zhanget al., ,**2 ). Among them, vio-lacustrine sediments called the Nihewan soricomorph and lagomorph remains are de- Formation, and was dated as+4-0 Ma by paleo- scribed systematically in this paper. The geo- magnetic method (Zhuet al., ,**+ ). It was logical setting of the layer and the screen- known that the layer had yielded mammalian washing procedure are explained in Zhang et remains in association with artifacts, but theal. (,**2 ). Received July,+, ,**1. Accepted January +3 , ,**2. * + Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, P.O. Box0.- , Beijing, +***..,China(Presentaddress : Graduate School of Science, Osaka City University.--+-2ῌῌ Sugimoto, Sumiyoshi-ku, Osaka,//2ῌ 2/2/ , Japan). *Dep,artment of Earth Sciences, Aichi University of Education. + Hirosawa, Igaya-cho,Kariya, ..2ῌ 2/.,,Japan. * a Corresponding author:[email protected]. ac. jp 160 Zhang, Y.Q. and Kawamura, Y. June ,**2 face of the crown, the posterior cingulum runs II. Terminology and measuring method along the posterior margin of the crown. It is Almost all the remains described herein are thick and not undulated. The cingulum con- detached teeth. Figure+ shows the terminol- tinues to the ventral face of the crown, and ogy and measuring method used for the teeth forms a knob at the linguo-ventral corner of of soricid soricomorphs, which follow those of the crown. On the lingual face of the crown, Kawamura (+33, , +33- ). Figure , also shows however, it is absent or feeble. The root is long those for the cheek teeth of ochotonid lago- and stout, and extends postero-dorsally. morphs, which mainly follow those of Lopezo M+ : In one of the two specimens described (V Martinez (+320 ). The measurements of the lago- +/-+24- ), the antero-buccal part of the crown is morph teeth were taken parallel to their occlu- lost (-- in Fig. ), but this part is observable in sal surfaces. another specimen (V+/-+24. ). The occlusal out- All the measurements were taken by using a line of the crown is squarish, and is not elon- measurescope (Nikon : MMῌ++ ) with an electric gated linguo-buccally so that W is only little digital counter (Nikon : CMῌ0/ ). larger than L (Table + ). The anterior border of the crown is gently convex anteriorly in occlu- III. Systematic description sal view. The buccal border of the crown is Order Soricomorpha Gregory,+3+* weakly emarginated both in its anterior and Family Soricidae Fischer de Waldheim,+2+1 posterior halves. The V o shaped ridge formed Subfamily Soricinae Fischer de Waldheim,+2+1 by the parastyle, paracone and mesostyle has Tribe Soricini Fischer de Waldheim,+2+1 nearly the same size and shape as that formed GenusSorex Linnaeus,+1/2 by the mesostyle, metacone and metastyle. A Sorex sp. postero-buccal protrusion of the metastyle is (Fig.- ) weak. In the lingual part of the crown, the pro- Referred specimensῌ+ left first upper incisor tocone is well developed, and forms a broad- (V+/-+24+ ) ; + right first upper incisor (V +/-+24, ) ; angled Vo shaped ridge, whose posterior part ,broken right M+, (V +/-+24-ῌ . ) ; + left M (V (postprotocrista) runs posteriorly. This ridge is +/-+24/) ; + broken left M+ (V +/-+240 ) ; + right separated from the lingual base of the meta- M,- (V+/-+241 ) ; + left M (V +/-+242 ). cone, and thus the trigon basin opens posteri- RepositoryῌAll the specimens are stored in orly. The hypocone is much smaller and lower the Institute of Vertebrate Paleontology and than the protocone, but shows a well-defined Paleoanthropology (IVPP), Chinese Academy conical shape. It is separated from the postpro- of Sciences, Beijing. tocrista by a shallow valley. The lingual bor- LocalityῌXiaochangliang site, about*4/ km der of the crown is gently emarginated, and a northwest of Guanting, Yangyuan County, He- short cingulum is observed along its central bei Province (IVPP field locality number12**/ ). part. The distocrista extends posteriorly from Geographic coordinates :++.῍῍ .*ῌῌ E, .* +- N. the apex of the hypocone to the postero-lingual HorizonῌUpper part of the Nihewan Forma- corner of the crown, where it forms a feeble tion defined by Wei (+331 ) cusplet. Furthermore it continues to the post- AgeῌEarly Pleistocene ; dated paleomagneti- cingulum, which runs along the posterior cally as+4-0 Ma. border of the crown and reaches the postero- DescriptionῌAll the specimens are secondar- buccal corner of the crown. The posterior emar- ily stained dark brown to brown, so that origi- gination is weak. nal pigmentation of their cusps cannot be de-M, : This tooth can be regarded as a small ver- tected. sion of M+ , but the following minor di# erences First upper incisor : The anterior cusp has are observed. W is almost equal to L (Table+ ). no medial cusplet, and thus this tooth is not The metastyle never protrudes postero-buccally. fissident. The posterior cusp is well developed, The postprotocrista bends at right angles, and and its apex reaches close to that of the ante- extends buccally to the base of the metacone. rior cusp in dorso-ventral level. On the labial The distocrista has no cusplet. ,**2῍ῌ 0 Soricomorphs and lagomorphs from the Xiaochangliang site 161 Fig.+ Terminology and measuring method for the soricid soricomorph teethdescribed here, according to Kawamura (+33,,) +33- bl : base line for measurement, h : height of crown, L : length of crown, W : width of crown. Fig., Terminology and measuring method for the ochotonid lagomorph cheek teethdescribed here, according to Lopezo Martinez ( +320 ) All the measurements are taken on the occlusal surface of each tooth. L : maximum length of crown, W : maximum width of crown, Wa:width of anterior loph in P- . 162 Zhang, Y.Q. and Kawamura, Y. June ,**2 Fig.- Detached teethofSorex sp. from the Lower Pleistocene of the Xiaochangliang site +. left first upper incisor (V +/-+24+ ), , . right first upper incisor (V +/-+24, ), - . right M+ (V +/-+24- ), . , left M (V+/-+24/ ), / . right M,- (V +/-+241 ), 0 . left M (V +/-+242 ). +῍῍ , . labial view, - 0 . occlusal view. M+ : The trigonid is mostly lost in the only rior part of the entocristid. The anterior end of specimen described. The oblique cristid is con- the entocristid is connected to the posterior nected to the posterior face of the protoconid. base of the metaconid. A well-marked cingulum is observed on theM- : The occlusal outline is also trapezoidal. posterior base of the hypoconid. The postcris- The trigonid is larger than the talonid. A dis- tid extends from the hypoconid to the posterior tinct cingulum starts at the anterior base of the base of the entoconid, but its lingual end is paraconid, extends along the anterior and buc- separated from the entoconid by a narrow cal faces of the crown, and terminates on the groove extending postero-lingually from the posterior base of the hypoconid. Another nar- talonid basin. The entoconid is a conical cusp, row cingulum runs along the lingual face of and separated from the metaconid by a depres- the crown. The talonid is longer than broad. It sion between them. The entocristid is not rec- is not reduced, and shows nearly the same ognized. A narrow cingulum runs from the shape as those of M+, and M . But owing to the postero-lingual base of the entoconid to the lack of the narrow groove between the lingual lingual base of the metaconid. end of the postcristid and entoconid, the talo- M, : The occlusal outline is trapezoidal. The nid basin becomes a closed depression sur- trigonid is nearly as large as the talonid, but rounded by a continuous ridge formed by the the former is slightly narrower than the latter. oblique cristid, hypoconid, postcristid, entoco- A distinct cingulum extends buccally from the nid and entocristid.