AMERICAN MUSEUM Novitates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2780, pp. 1-17, figs. 1-8, table 1 February 8, 1984 Prosarcodon lonanensis, a New Paleocene Micropternodontid Palaeoryctoid Insectivore from Asia MALCOLM C. MCKENNA,1 XUE XIANGXU,2 AND ZHOU MINGZHEN3 ABSTRACT A new genus and species of primitive microp- currence of the micropternodontids prior to their temodontid soricomorph insectivores, Prosarco- apparent restriction to North America. The pe- don lonanensis, is described from the Paleocene trosal bone of Prosarcodon is similar to that of Fangou Formation, Shaanxi Province, People's Palaeoryctes puercensis from the North American Republic of China. Prosarcodon lonanensis sheds Paleocene. Prosarcodon and Sarcodon were both new light on the origin of the mammalian family specialized in the loss ofa molar, unlike the youn- Micropternodontidae, linking them to the Palaeo- ger genus Sinosinopa from Inner Mongolia (Nei ryctoidea and demonstrating an early Asian oc- Mongol), PRC. INTRODUCTION Among collections of Chinese Paleogene ious anagalids from the Chinese Paleogene, mammalian fossils there are 17 species of the earliest previous records ofChinese fossil insectivores (sensu lato) from various strati- insectivores are Sarcodon from the upper Pa- graphic levels at more than a dozen major leocene or lower Eocene of North China and localities. Most of them are erinaceids from the MPR and Hyracolestes from the upper the Oligocene. Thus far, Cretaceous insecti- Paleocene or lower Eocene of the MPR and vores and insectivore-like animals such as the upper Paleocene ofAnhui Province, PRC. Prokennalestes, Kennalestes, Asioryctes, Za- The affinities of most of the early non-eri- lambdalestes, Barunlestes, Deltatheridium, naceoid insectivores of Asia have been dis- Deltatheroides, and Hyotheridium have not puted in one way or another. Sarcodon is no been found in China although they occur exception. With the description of Prosar- nearby to the north in the Mongolian Peo- codon, presented here, we hope to throw some ple's Republic (MPR). Except Endotherium much-needed light on the relationships of from the Chinese Lower Cretaceous and var- Sarcodon, Sinosinopa, Palaeoryctes, and the ' Frick Curator, Department of Vertebrate Paleontology, American Museum of Natural History. 2 Instructor, Department of Geology, Northwest University, Xian, Shaanxi, PRC. 3Research Professor, Institute of Vertebrate Paleontology and Paleoanthropology, Academia Sinica, Beijing, PRC. Copyright © American Museum of Natural History 1984 ISSN 0003-0082 / Price $1.55 2 AMERICAN MUSEUM NOVITATES NO. 2780 FIG. 1. Map of Shaanxi Province, PRC, showing location of Xian, Lonan, and Shimen. peculiar "American" insectivore family Mi- ulated jaws of a Sarcodon-like insectivoran cropternodontidae. was discovered by Xue and technician Zhao In 1977 fossil mammals were found (Xue, Jufa in deposits of early or middle Paleocene 1978) and in 1978 a small skull with artic- age in the lower part of the Fangou Forma- 1 984 MCKENNA, XUE, AND ZHOU: PROSARCODON LONANENSIS 3 tion, Fangou Valley, near Shimen Commune, Pleistocene Lonan County, Shaanxi Province, PRC (fig. 1). The Shimen Basin is small, fault-bound- 2 _0 0 0 0 ed, and was formed in Sinian (Precambrian) E o .o. 220- quartzites and marbles during the early Ter- tiary. The basin is only about 52 km.2 in area and is about 110 km. east of Xian (170 km. 0 00 z 0000 t0| o 0 20 by road), about 15 km. north from Lonan, -00 00_ 200 capital city ofLonan County, in the northern CD0 W part of the Qinling Range at its boundary 0 with the North China Platform. Many other o 0L2 0 o small fault-controlled basins exist in the o -0-0-. i Qinling Range. The Shimen Basin contains three Cenozoic 1 z o co 0 rock units above its Sinian basement (Xue 0.0 and Jufa, 1982): w Pleistocene Alluvium and 0. talus ____ . 40 Fm. Upper Miocene Gedamiao Red clay, con- o 000LFB. 120- or Pliocene (68 m.) glomerate, with Hippari- z on, etc. 0. Lower or middle Fangou Fm. Brown-red, sandy Paleocene (165 m.) mudstone Precambrian Gaushanhe Fm. Quartzite and marble 0- o o -- The Fangou Formation is about 165 m. thick (fig. 2) and is unconformable both with ______ the underlying Precambrian basement and 00 with the overlying Neogene Gedamiao For- o o o O 60 mation. The Fangou Formation is distrib- uted widely in the Shimen Basin and consists ofbrown-red, dense, sandy mudstones. These mudstones contain green deoxidation spheres oo oH C and are cut by a network ofinclined fractures filled with gypsiferous material. The Fangou Formation can be divided informally into upper and lower parts: the mudstones of the upper part (41 m.) of the Fangou Formation are interlayered with several gray-green con- glomeratic sandy mudstones and silty sand- stones containing many calcareous concre- tions about 2 cm. in diameter. The lower part (124 m.) of the Fangou Formation contains FIG. 2. Generalized geological section of Ter- tiary deposits of the Shimen Basin, Shaanxi, PRC. several thin conglomeratic layers in the mid- LFB-lower fossiliferous beds where Prosarcodon dle and a thick one at the base. lonanensis and other Paleocene mammals were There are two fossil-bearing beds in the found (lower circle with cross). UFB-upper fos- Fangou Formation. One specimen of a bem- siliferous beds where one specimen of a bema- alambdid pantodont has been collected from lambdid pantodont has been recovered (upper cir- the upper fossil-bearing beds about 6 m. above cle with cross). Scale in meters. 4 AMERICAN MUSEUM NOVITATES NO. 2780 the base ofthe upper part ofthe Fangou For- chen" becomes "Zhou Mingzhen," etc. Also, mation, but the remaining fossils collected unless quoted from previous usage, Chinese thus far were found about 6 m. below the top family names ofauthors are listed before giv- of the lower part of the Fangou Formation, en names and are not separated by a comma where specimens of the anagalid genus Lin- from given names. nania, bemalambdid pantodonts, and the mesonychid Hukoutherium occur in addition ACKNOWLEDGMENTS to the palaeoryctoid Prosarcodon lonanensis. We thank Drs. Zhai Renjie of the IVPP, In both lithostratigraphy and fauna, as well and M. R. Dawson, M. J. Novacek, P. V. as geological structure, the Shimen Basin is Rich, and L. Van Valen for advice and other very similar to the Nanxiong Basin ofGuang- aid, Mr. Zhao Jufa for aid in the field, and dong Province in South China. The Fangou the IVPP staff for a cast ofthe type specimen Formation can be compared favorably with of Sinosinopa sinensis. Dr. R. J. Emry per- the Shanghu Formation of the Nanxiong Ba- mitted us to study the type specimen ofKen- sin. The two fossiliferous beds in the Fangou trogomphios strophensis and Dr. Dawson gave Formation are older than the dated parts of us access to various specimens in her care. the Taizichun Formation ofXinjian or ofthe Preparation of the type specimen of Prosar- Loumugeng Formation of Nei Mongol, PRC codon lonanensis was skillfully executed by (Inner Mongolia). Zhao Jufa and Otto Simonis. The illustra- The specimen from the Fangou Formation, tions were prepared by Messrs. Chester Tarka here made the type of Prosarcodon lonanen- and Raymond Gooris. This project was sup- sis, is poorly preserved and dorsally incom- ported in large part by a grant to Xue from plete, but the jaws and dentition remain gen- the Geological Academia Sinica for fieldwork erally in excellent condition and part of the and travel, partly by the American Museum basicranium is still present. The animal is, as of Natural History, partly by the Carnegie would be expected, somewhat more primi- Museum ofNatural History, and, with regard tive than Sarcodon. to travel expenses, partly by a U.S. National Science Foundation grant to Dr. R. M. Hunt at the University of Nebraska. INSTITUTIONAL ABBREVIATIONS AND ORTHOGRAPHY ORDER SORICOMORPHA GREGORY, 1910; MCKENNA, 1975 AMNH, American Museum of Natural History, New York, New York. SUPERFAMILY PALAEORYCTOIDEA WINGE, CMNH, Carnegie Museum of Natural History, 1917; VAN VALEN, 1963 Pittsburgh, Pennsylvania. FAMILY MICROPTERNODONTIDAE STIRTON IVPP, Institute of Vertebrate Paleontology and AND RENSBERGER, 1964 Paleoanthropology, Academia Sinica, Beijing, PRC. (=MICROPTERNODIDAE STIRTON MPR, Mongolian People's Republic. AND RENSBERGER, 1964; PRC, People's Republic of China. MICROPTERNODONTIDAE VAN VALEN, 1965; UM, University of Michigan Museum of Paleon- MICROPTERNODONTINAE VAN VALEN, 1966) tology, Ann Arbor, Michigan. USA, United States of America. PROSARCODON MCKENNA, XUE, USNM, National Museum of Natural History, AND ZHOU, NEW GENUS Smithsonian Institution, Washington, D.C. 20560. TYPE: Prosarcodon lonanensis McKenna, WNUG, Department ofGeology, Northwest Uni- versity, Xian, Shaanxi, PRC. Xue, and Zhou, new species. LOCALITY, ASSOCIATED FAUNA, AGE, AND Except where quoted from previous usage, DISTRIBUTION: As for the type species. all names from the Chinese language (Man- ETYMOLOGY: Pro, first, early, in allusion to darin, Beijing Dialect) are rendered here in the supposed ancestral position of this genus English in the current version ofPinyin. Thus, with regard to Sarcodon. Sarcodon, name of "Fan-gou" becomes "Fangou," "Chow Min- a latest Paleocene or earliest Eocene genus of 1984 MCKENNA, XUE, AND ZHOU: PROSARCODON LONANENSIS 5 Mongolian and Chinese fossil soricomorph tooth, but it lacks any sort of a cutting crest insectivores. on its posterior side and is therefore oval DIAGNOSIS: As for the type species. rather than triangular in cross-section. P' (or dP') is a small, single-rooted, pierc- Prosarcodon lonanensis McKenna, ing tooth that tilts forward slightly. Its rear Xue, and Zhou, new species slope is crested, as in Sinosinopa sinensis. Figures 3-7 Following a short diastema behind PI, the upper dentition (figs. 3, 4) is continuous TYPE: WNUG specimen no. 78ShOO 1, through M2. p2 is a double-rooted, piercing fragmentary skull and jaws.