Protalactaga major, GROUPS

ZHUDING, QIU & CHUANKUEI, LI, 2003, Chapter 22: Rodents from the Chinese Neogene: Biogeographic Relationships with Europe and North America, Bulletin of the American Museum of Natural History 279, pp. 586-602 : 590-597

MAJOR GROUPS OF CHINESE NEOGENE RODENTS

One hundred and twenty­six genera of rodents within 25 groups (families and subfamilies) and representing Protrogomorpha, Sciuromorpha, Myomorpha, and Hystricomorpha are known in the Chinese Neogene. Figure 22.3 lists major groups of Neogene rodents with their temporal and geographical distribution, and relationships to Europe and North America.

CTENODACTYLIDAE : Ctenodactylidae flourished in central and northeastern Asia during the Oligocene, but declined greatly in the early Miocene and made their last occurrence in the early middle Miocene of Dingjiaergou. Six genera, Tataromys , Yindirtemys , Prodistylomys , Distylomys , Prosayimys , and Sayimys , grouped in three subfamilies, Tataromyinae , Distylomyinae, and Ctenodactylinae , have been reported mainly in the Mongolia –Xinjiang areas and northern edge of Qinghai–Tibet Plateau. All the genera except Sayimys can be found in Oligocene deposits (Wang, 1977) at low abundance except for the common Yindirtemys . Survivors migrated southwestward through Asia to the Mediterranean area and North Africa after the early Miocene, and were affected by change of environment caused by uplift of the Himalayas. See Wang’s (1997) significant revision of the family.

TACHYORYCTOIDIDAE: Two genera of this family, Aralomys and Tachyoryctoides , have been recognized in the same regions where ctenodactylids occur. Aralomys is known from Kazakhstan and is represented by quite a number of specimens from Suosuoquan, which were previously reported as Tachyoryctoides obrutschewi and T. pachygnathus ( Qiu et al., 1999) . Li and Qiu (1980) described Tachyoryctoides kokonorensis from Xiejia (early Miocene) and indeterminate species of this genus were reported at Halamagai, Zhangjiaping, Dingjiaergou, Wuertu, and Gashunyinadege ( Qiu et al., 1999; Qiu and Wang, 1999). It is clear that the two genera are survivors from Oligocene faunas, and endemic to central and northeastern Asia. They coexisted with and disappeared simultaneously with ctenodactylids in the Miocene.

TSAGANOMYIDAE : Tsaganomys is the only Neogene genus of Tsaganomyidae , and it first appeared in the early Oligocene in the Mongolian plateau. Tsaganomys cf. altaicus collected from Gaolanshan (previously Lanzhou) represents the last record of the family ( Qiu et al., 1999).

DIATOMYIDAE : Diatomys shantungensis , collected from Shanwang and Sihong, is the only Chinese species of this family. Diatomys was first considered indeterminate to family and questionably referred to Geomyoidea ( Li, 1974). Some students transferred it to the family Pedetidae ( McKenna and Bell, 1997) . We follow P. Mein and L. Ginsburg (1997) in their definition of a new family for this genus plus probably Fallomus . Diatomys is also known from Thailand, Pakistan, and Japan ( Kato and Otsuka, 1995), and appears to be a kind of wet/warm­adapt­ ed animal distributed in a tropical or subtropical area.

APLODONTIDAE : Aplodontid rodents are quite well known in Holarctic Oligocene deposits in Europe and North America, but are represented in China by scarce materials of four genera. These are Promeniscomys , Haplomys , Prosciurus , and Ansomys , of which only Ansomys survived into the Miocene ( Rensberger and Li, 1986; Qiu, 1987; Wang, 1987). Ansomys may have evolved from a Prosciurus ­ like ancestor, and made its first appearance in the early Miocene. Ansomys orientali s was described from Sihong and A. shanwangensis from Shanwang ( Qiu, 1987; Qiu and Sun, 1988), and questionable Ansomys was reported from Gashunyinadege, Tunggur, Amuwusu, and Shala of Inner Mongolia ( Qiu and Wang, 1999). In addition, the aplodontine Pseudaplodon is known from the Mio/Pliocene of Ertemte and Harr Obo, Inner Mongolia, and represents the last record of this family in Asia ( Fahlbusch et al., 1983). An upper and a lower premolar from Amuwusu, similar to those of Meniscomys of North America, may represent a meniscomyine rodent in the Old World.

MYLAGAULIDAE : Mylagaulids are quite diverse in North America, and also known from Zaisan Basin, Kazakhstan. Sinomylagaulus halamagaiensis described by Wu (1988) from Halamagai Formation, Junggar Basin, represents the only record of this family in China.

SCIURIDAE : We recognize 23 genera of sciurid rodents, with Sihong, Ertemte, Shihuiba (Lufeng), and Wushan being relatively diverse and common squirrel faunas ( Qiu et al., 1985; Qiu and Lin, 1986; Qiu, 1991; Zheng, 1993). An undiagnosed new species of Palaeosciurus from Suosuoquan represents the oldest record of the family ( Qiu et al., 1999). Palaeosciurus , Eutamias , Sciurus , Tamiasciurus , Atlantoxerus , Heteroxerus , Sciurotamias , Miopetaurista , Pliopetaurista , Petinomys , Albanensia , Pteromys , and Hylopetes show affinities either to Europe or to North America, whereas Sinotamias , Prospermophilus , Tamiops , Callosciurus , Dremomys , Parapetaurista , Shuanggouia , Plesiosciurus , Meinia , and Belomys are restrict­ ed in geographical distribution to Asia. Generally, sciurids were not so diverse as they were in Europe and North America during Neogene time, and flying squirrels are not as common as they are in European sciurid faunas. Sciurids found in China demonstrate apparently ecologic provinciality throughout the Neogene, with dominance of ground squirrels in the north, and of tree and flying squirrels in the south.

CASTORIDAE : Eight genera of beavers, Youngofiber , Anchitheriomys , Steneofiber ,? Hystricops , Castor , Dipoides , Trogontherium , and Eucastor , have been recovered from Sihong, Tunggur, Halamagai, Amuwusu, Yushe, Ertemte, Bilike, and Wushan ( Li, 1963; Chow and Li, 1978; Zheng, 1993; Xu, 1994; Qiu, 1996a; Flynn et al., 1997; Wu et al., 1998). All the taxa, except Youngofiber , can be found in the European and North American Neogene. Youngofiber was a massive form also known from Mizunami, Japan ( Tomida and Setoguchi, 1994) as well as Sihong. The occurrence together with Diatomys in both places suggests existence of a connection between the Chinese mainland and the Japanese islands during the early Miocene. An indeterminate genus from Shihuiba and ’’ Castor ’’ from Zhaotong, Yunnan, represent the southernmost records of beavers in China, even in the Old World. Associated with the beavers at Shihuiba are some small mammals confined to the present tropical or subtropical areas, such as tree shrew, mole shrew, spiny dormouse, and bamboo rats ( Qiu et al., 1985). Xu (1994) presented a thorough review of castorid rodents found in North and East China.

EOMYIDAE : Eomyids are another cosmopolitan group of fossil rodents, but they are poorly diversified with limited material in China. Two genera, Keramidomys and Leptodontomys , have been determined from early Miocene (Gashunyinadege) through early Pliocene (Harr Obo) localities, and these usually occur together in the Miocene deposits of North China ( Zheng and Li, 1982; Fahlbusch et al., 1983; Qiu, 1996a; Qiu and Wang, 1999). Keramidomys failed to persist into the Pliocene. An undetermined genus of this family from Shihuiba is a bunodont eomyid, which shares dental similarities with Eomys or Pentabuneomys of Europe, or with Adjidaumo of North America ( Qiu, 1994).

GLIRIDAE : Since the finding of Myomimus at Ertemte, dormouse material has been found at several localities, one after another. Nevertheless, only three genera, Microdyromys , Miodyromys , and Myomimus , are recognized, and specimens of the first two taxa are rather rare ( Wu, 1985, 1986; Qiu, 1996a; Flynn et al., 1997; Wu et al., 1998; Qiu and Wang, 1999). All three genera are commonly known in Europe, but do not occur in South China. Neither Microdyromys nor Miodyromys survived into the Pliocene.

PLATACANTHOMYIDAE : Platacanthomys and Typhlomys , confined to the present Oriental region, are known from Shihuiba ( Qiu, 1989) and Yuanmou recently. Zheng (1993) described three species of Typhlomys from Wushan. An isolated tooth from Sihong, assigned to Neocometes , represents the third genus of platacanthomyid rodents found in China. The latter is also known from Thailand. Remains of these animals are not found in North China.

ZAPODIDAE : The nine genera representing this family in North China are Litodonomys , Parasminthus , Heterosminthus , Eozapus , Protozapus , Sinozapus, Plesiozapus , Sicista , and Lophocricetus . Litodonomys and Parasminthus are known only from early Miocene localities, such as Suosuoquan and Xiejia, whereas Heterosminthus is mainly middle Miocene, Quantougou, Dingjiaergou, and Tunggur, for example ( Li and Qiu, 1980; Qiu, 1996a; Qiu et al., 1999). Remains of the other forms derive mainly from the late Miocene and Pliocene deposits. Eozapus , Sicista , and Lophocricetus are common members of the Ertemte and Harr Obo faunas (Qiu, 1985; Fahlbusch, 1992). Specimens of Protozapus reported from Wenwanggou and Plesiozapus from Amuwusu are inadequate and need further identification. Only Eozapus and Sicista persist to the present day.

DIPODIDAE : Neogene dipodid rodents found include Protalactaga , Paralactaga , Sminthoides , Brachyscirtetes , and Dipus . The earliest Neogene record of this family is an indeterminate species of Protalactaga represented by an upper molar from Wuertu fauna ( Qiu et al., 1999); that it possibly is a derived species of Parasminthus cannot be excluded. Protalactaga occurs usually in the middle Miocene of North China, such as in the Quantougou, Tunggur, and Dingjiaergou faunas. These rather primitive jumping mice failed to survive into the late Miocene. The other genera are known from the late Miocene and Pliocene (the indeterminate species of Paralactaga from Dingjiaergou in a previous faunal list may be Protalactaga major ). Sminthoides is quite common in late Neogene deposits, whereas Brachyscirtetes and Dipus are relatively scarce. The questionable Dipus from Amuwusu probably represents the first record of the three­toed jerboa. Both zapodids and dipodid rodents are found only in North China.

PARACRICETODONTINAE : Eucricetodon youngi from Xiejia is the only representative of this group found in the Neogene of China ( Li and Qiu, 1980). The indeterminate species previously reported as Eumyarion sp. based on a lower molar from Tunggur has been transferred to Gobicricetodon ( Qiu, 1996a) .

CRICETODONTINAE : Five genera in this group, Megacricetodon , Democricetodon , Primus , Spanocricetodon , and Paracricetulus , have been recovered from the early and middle Miocene. Megacricetodon and Democricetodon had a large geographic distribution and made their first appearance in early Miocene (Sihong, Wuertu, Gashunyinadege) as in Europe. They seem to have thrived in North China in the middle Miocene. Wessels (1996) argued that Megacricetodon did not occur in Pakistan and that all material from the Indian subcontinent previously assigned to Megacricetodon should be allocat­ ed as the myocricetodontine Sindemys. The tiny cricetodontine Primus is known from the early Miocene of Pakistan, and similar species occur in the equivalent age Sihong fauna. Spanocricetodon from the Shanwangian of eastern China (Fangshan) is also known from Pakistan and Thailand. Young (1927) described Paracricetulus schaubi from Hsien Shui Ho (Quantougou) based on a fragmentary upper jaw with a damaged M1. Additional material has been collected from the type locality, and further study will deepen understanding of this genus. Cricetodon itself, which is known from the Miocene of Europe and western Asia, seems not to appear in eastern Asia. Records of ‘‘ Cricetodon ’’ from Suosuoquan, Dingjiaergou, and a similar genus from Sihong are misidentified (vide infra).

GOBICRICETODONTINAE: Gobicricetodontine rodents are relatively large­size cricetids with mesodont and bunolophodont cheek teeth, and include two genera, Plesiodipus and Gobicricetodon . Plesiodipus is known from several middle and early late Miocene localities of North China (Lierpu in Xining Basin, Quantougou, Tunggur, and Amuwusu). It was thought to include ancestry of siphneines, which flourished later in northeastern Asia ( Qiu et al., 1981). Qiu (1996a) described two species of Gobicricetodon from Tunggur. Previously reported Cricetodon sp. from Suosuoquan, Halamagai, Dingjiaergou, and Amuwusu should be referred to this genus.

CRICETINAE : Cricetines rapidly replaced the archaic cricetids and diversified since the late Miocene. Including Wushan in the late Pliocene, 11 genera of this group, Sinocricetus , Nannocricetus , Kowalskia , Neocricetodon , Bahomys , Cricetulus , Cricetinus , Allocricetus , Phodopus , Chuanocricetus , and Amblycricetus , have been recognized in the late Neogene. Sinocricetus and Nannocricetus from Shala in North China and Kowalskia from Shihuiba in South China represent the first appearance of this subfamily (Baodean age). They are quite common in the late Miocene and early Pliocene faunas (Ertemte, Yushe, Bilike, Wenwanggou, etc.). Neocricetodon is known only from the late Miocene of Yushe ( Schaub, 1934; Flynn et al., 1997). Bahomys , a form of cricetid with rather complex occlusal structure, was first described from the Pleistocene of Lantian ( Chow and Li, 1965), and recently reported from the Pliocene of Wenwanggou ( Zheng and Zhang, 2000). The six other genera occur in the Yushean Pliocene (Yushe Basin, Wenwnggou, and Wushan). Differential diagnosis of these taxa is not so clear, and definition and reallocation of late Neogene cricetines remains undone. In addition, three damaged teeth from Shala have been referred to Microtocricetus , but this taxon awaits more material for confirmation.

GERBILLINAE : Pseudomeriones is the single published representative of this group, and occurs frequently in the late Miocene and Pliocene of North China (Qingyang, Yushe, Ertemte, Wenwanggou, Bilike, and Ningxi­ an). Two species of the genus, at different stages of evolution, have been recognized ( Teilhard, 1926; Zhang, 1999).

MICROTOSCOPTINAE: Microtoscoptine rodents have a Holarctic distribution. Microtoscoptes , first named by Schaub in 1934, represents this subfamily in China. Fahlbusch (1987) described the additional material from Ertemte and Harr Obo in detail. More recently remains of this animal have been reported from Shala that may represent the earliest record of the genus ( Qiu and Wang, 1999).

BARANOMYINAE: Two taxa can be referred to Baranomyinae. These include Microtodon atavus and Anatolomys teilhardi from Ertemte, Harr Obo, and Bilike of central Inner Mongolia. They are very common in the Ertemte and Harr Obo faunas, but rare in Bilike. Baranomyine rodents seem to be replaced by the arvicolines that arise abruptly during the early Pliocene in this region, and persist into the Pleistocene only in eastern Europe.

SIPHNEINAE: Siphneines are a group of rodents derived probably from a Pleisodipus ­ like ancestor and endemic to central and northeastern Asia. They made their first occurrence in the very early late Miocene (Amuwusu) and had a rapid Pliocene radiation in the great land mass. They are commonly known in the late Neogene faunas of North China (see table 22.1) and are potentially very useful in biochronological correlations. On the basis of the presence or absence of molar roots, Teilhard and Young (1931) assigned these animals to two genera—the rooted Prosiphneus and rootless Siphneus (= Myospalax ). Zheng (1994, 1997), however, based on patterns of their occipital shield and corresponding skull features, grouped them into three subfamilies, the convex­skulled Prosiphneinae, the flat­skulled Myospalacinae, and the concave­skulled Mesosiphneinae, comprising together 10 genera. Zheng’s proposal may be reasonable, but incomplete knowledge of skulls and great molar similarity in various species make it difficult to allocate the isolated teeth that usually occur in deposits. In addition, evolutionary relationships of the diverse extant Myospalax species with various siphneines remain to be solved. According to Zheng’s definition, the Neogene siphneine genera are Myotalpavus , Prosiphneus , Chardina , Mesosiphneus , Pliosiphneus , Episiphneus , and Youngia . The first two appeared in the late Miocene, whereas the others are Pliocene.

ARVICOLINAE : High­crowned rodents evidently increased in abundance in northeastern Asia since the late Miocene. Like the microtoscoptines, baranomyines, and siphneines in the late Miocene, arvicolines show a Pliocene radiation. Aratomys , Mimomys , Germanomys , Hyperacrius , Villanyia , Microtus , Clethrionomys , and Eothenomys are the genera of this group found in the Pliocene of China. The oldest certain arvicoline is Aratomys from the early Yushean, which dominates the Bilike fauna ( Qiu and Storch, 2000). Zheng and Li (1986, 1990) reviewed the Mimomys of China. Since then, more material has been recovered from Yushe, Wenwanggou, and Daodi. Germanomys is reported from Yushe, Daodi, and Jingle. The later arvicolines include the poorly known Hyperacrius , Villanyia , and Microtus from Dachai, and Clethrionomys and Eothenomys from Wushan ( Zheng and Li, 1990; Zheng, 1993).

RHIZOMYIDAE : Fossil rhizomyids in eastern Asia are not so diverse as in the Siwaliks of Pakistan and India. An indeterminate rhizomyid from Sihong (also Shanwang) represents the earliest record of the family in China. Only subfamily Rhizomyinae is certainly recognized in the Neogene deposits. They are primitive species of Rhizomys (Brachyrhizomys) from Lufeng and Yuanmou, and more advanced Rhizomys (Brachyrhizomys) shansius from Yushe. Flynn (1993) added a species of Rhizomys to the Miocene fauna of Yushe. Flynn and Qi (1982) and Qi (1986) described three species of Brachyrhizomys from Lufeng, which occur together at about 8 Ma in Pakistan. A species reported previously as Brachyrhizomys hehoensis from Bulong, Tibet, is considered congeneric with Pararhizomys ( Jacobs et al., 1985) . Pararhizomys from Fugu, Shanxi, is poorly known and, if truly a rhizomyid, represents the northernmost distribution of this family in China. Rhizomys occurs also in the late Pliocene fauna of Wushan ( Zheng, 1993).

MURIDAE : Murid rodents appeared in China much later than in the Indian subcontinent. Progonomys and Yunomys associated with hominoids and Brachyrhizomys from Shihuiba, Lufeng, are considered the oldest murids so far known in China ( Qiu and Storch, 1990), but an undescribed Progonomys from Lantian, Shaanxi, may represent a murid appearing earlier than those of Lufeng (Zhaoqun Zhang, personal commun.). The murid group has really flourished since the latest Miocene. At least 19 genera of this group have been recognized, with the Lufeng, Ertemte, Harr Obo, Bilike, Yushe, Wenwanggou, Daodi, and Wushan faunas being the most productive. Apodemus , Orientalomys , Karnimata , Occitanomys , and Micromys occur in Ertemte and Harr Obo. In addition to these elements, Chardinomys and Huaxiamys are often found in the Pliocene, as at Yushe, Bilike, Wenwanggou, and Daodi ( Jacobs and Li, 1982; Wu and Flynn, 1992; Cai and Qiu, 1993; Flynn et al., 1997; Qiu and Storch, 2000; Zheng and Zhang, 2000). Huaxiamys , Chardinomys , and Allorattus were apparently restricted in geographical distribution to the Pliocene of North China. Storch (1987) reported Rhagapodemus from Harr Obo. Saidomys is known from the late Pliocene of Afghanistan and occurs in the equivalent age fauna of Daodi. Further, Zheng (1993) determined Mus , Hapalomys , Chiropodomys , Vernaya , Leopoldamys , Niviventer , and Wushanomys from Wushan, which represent the earliest occurrence of these genera.

HYSTRICIDAE : Porcupines are quite common in the Pleistocene faunas of South China. Neogene hystricids are represented by a single genus, Hystrix , with limited specimens. An indeterminate species from Shihuiba is the oldest record of the genus so far known ( Qiu et al., 1985). Porcupines extend­ ed northward to Yushe in distribution during the Pliocene ( Flynn et al., 1997). Zheng (1993) reported H. subcristata and H. magna from Wushan, which herald the common porcupines of the Pleistocene.

Figures

Fig. 22.1. Distribution of Neogene rodent localities in China. , Early Miocene (Xiejian + Shanwangian): 1, Suosuoquan; 2, Xiejia; 3, Gaolanshan; 4, Zhangjiaping; 5, Gashunyinadege; 6, Wuertu; 7, Shanwang; 8, Sihong (Songlinzhuang, Zhengji, Shuanggou); 9, Fangshan. v, Middle Miocene (Tunggurian): 10, Halamagai; 11, Quantougou; 12, Lierpu (Qijia, Danshuilu); 13, Dingjiaergou; 14, Tunggur; 15, Tairum Nor. M, Late Miocene (Baodean): 16, Songshan; 17, Bulong; 18, Jilong; 19, Qingyang; 20, Baode; 21, Lantian (Bahe); 22, Amuwusu; 23, Shala; 24, Baogedawula; 25, Ertemte (Harr Obo); 26, Shihuiba; 27, Yuanmou. ·, Pliocene (Yushean): 28, Bilike; 29, Jingle; 30, Dingcun; 31, Youhe; 32, Daodi; 33, Zhoukoudian (Cap Travertine); 34, Yinan; 35, Zhaotong; 36, Wushan.., Late Miocene + Pliocene: 37, Yushe (Mahui; Gaozhuang; Mazegou; Haiyan; Jiayucun); 38, Lingtai (Wenwanggou).