1924. Dicerorhinus orientalis Ringström, p. 5–25, figs. 1–8, pls. I.

1959. Dicerorhinus orientalis var. ringstroemi Arambourg, p. 73.

1978. Dicerorhinus orientalis (Ringström, 1959) - Liu et al., p. 176.

1978. Dicerorhinus ringstroemi (Arambourg, 1959) - Yan, p. 31, pl. I-1.

2004. Dicerorhinus ringstroemi (Arambourg, 1959) - Deng and Wang, p. 222–225, fig. 4.

2006b. Dicerorhinus ringstroemi (Arambourg, 1959) - Deng, p. 51–52, fig. 3.

2011. Dihoplus ringstroemi (Arambourg, 1959) - Deng et al., p. 1287, fig. 2.

Diagnosis: Larger than Dicerorhinus orientalis; skull is long; nasal bone is long and wide and has a domed horn boss; nasal notch above P3/P4; anterior border of orbit above M2; frontal horn boss small; sagittal crest absent; subaural channel closed; I2 and i1 absent, I1 and i2 reduced; P1 lost; molars with developed crochet (Deng, 2006b and Geraads, 1988).

Specimens: Complete toothrows and almost complete crania (Fig. 1, Fig. 2 and Fig. 3), mandibles, forefoot bones, tibia, metacarpals and talus.

Localities: Xin’an, Henan; Baode, Shanxi; Lantian, Shaanxi; Jingmen, Hubei; Qaidam, Qinghai; Linxia, Gansu.

Horizon: From late Miocene to Early Pliocene, corresponding to NMU 9 to NMU 12 (Deng and Downs, 2002).

Remarks: The specimens allocated to this species were referred to Dicerorhinus orientalis before the 1960s. In 1959, Arambourg established the new variety, Dicerorhinus orientalis var. ringstroemi, for the Neogene dicerorhines from China. The reason was that the Chinese specimens are much more robust than Dicerorhinus orientalis. However, Arambourg did not designate a type, and later, that variety was raised to species rank (Yan, 1978).

Although this species has been reported from several localities, fossils of it are fairly scarce. Except for one nearly complete cranium and some deciduous tooth rows, most of the specimens are fragmentary and isolated. This species is not well known.

Concerning its phylogenetic relationships, it differs from the extant D. sumatrensis not only in its larger size, but also in the following aspects: deeply saddled in the fronto-parietal part of the cranium; lacking upper incisors; a closed subaural channel and a very well developed nasal bone. I propose that the generic attribution of the Neogene dicerorhines should be reconsidered. In Europe, the Miocene dicerorhines were allocated either to Dihoplus Brandt, 1872 or to Lartetotherium Ginsburg, 1974 (Heissig, 1999). In that taxonomic scenario, the genus Dicerorhinus only encompasses the living species D. sumatrensis according to Groves (1983). Under such a situation, it is better to move the species D. ringstroemi to the genus Dihoplus as proposed by Deng et al. (2011). The phylogenetic position of the species D. ringstroemi is still uncertain.

Diagnosis: Small size; naso-frontal part flat, nasal tip bends downward; nasal notch reaches the level anterior to DP1; infraorbital foramen is at the level of the posterior border of DP1; premaxilla very thin and extends downward; mandible gracile; inferior border of mandibular corpus slightly convex, and rises in the symphysis part; symphysis is narrow and long; angular part extends backward; cheek teeth small and brachyodont; upper molars block-shaped, parastyle rib developed; protocone constriction weak; without anticrochet and crista; no lingual cingulum; two pairs of lower deciduous incisors, di1 bean-shaped, di2 caniniform, i2 moderately developed (in alveolus); dp2 smaller than usual (partially modified from Chen and Wu, 1976).

Holotype: Broken cranium with mandible of a juvenile individual (IVPP V4833).

Type locality: This species is known from a single locality, Jiulongkou, Cixian County, Hebei Province (Chen and Wu, 1976).

Horizon: Mid-Middle Miocene, correlated with MN Zone 6 (Deng, 2006a).

Remarks: The following characters make it reasonable to refer these specimens to the genus Dicerorhinus rather than to the tribe Aceratheriini: nasal bone developed but not straight, relatively advanced DP1 and dp1, narrowed mandibular symphysis with moderately developed i2 (in alveolus). In contrast, D. cixianensis is much smaller than the Quaternary two-horned or tandem-horned rhinoceros, and even smaller than the extant species. The DP1–4 length is only 119 mm and the dp1–4 length is 110 mm, which is much smaller than the only available data (DP1–4 length is 130 mm) measured from the Neolithic D. sumatrensis from Hemudu (the measurement was taken from the drawings by Wei et al., 1989). It is very probable that D. cixianensis represents the smallest species in the tribe Rhinocerotini, but this only can be verified when an adult skull is found.

2001. Rhinoceros sinensis (Owen, 1870) - Li and Feng, p. 35, pl. 6.

2008. Rhinoceros sinensis (Owen, 1870) (partim) - Echassoux et al., pp. 294–306, figs. 25–26.

Diagnosis: Large zygomatic width relative to cranial length; small size; two horns; occasionally with bony nasal septum; nasal notch and anterior border of orbit moved backward; postglenoid not fused with post-tympanic; sagittal crest absent; occipital plane sub-vertical, occipital outline trapezoidal; orbitonasal length surpassing orbitoaural length; occipitonasal and condylonasal lengths are subequal; I² and I₁ absent, I¹ and I₂ reduced; P¹ absent; molars with crochet (Fig. 1, Fig. 2, Fig. 3 and Fig. 4) (Geraads, 1988, Groves, 1967, Loose, 1975, Pocock, 1945 and Tong and Guérin, 2009).

Referred specimens: Broken cranium, mandibles, isolated teeth and few postcranial bones.

Localities: Liucheng Gigantopithecus Cave, Guangxi (Tong and Guérin, 2009); Xiawanggang, Henan (Chia and Chang, 1977); Yuyao, Zhejiang (Wei et al., 1989) and Yunxian, Hubei.

Horizon: Early Pleistocene to Holocene.

Remarks: The earliest record of D. sumatrensis is from the Early Pleistocene Liucheng Gigantopithecus Cave, Guangxi; the fossil material mainly includes isolated teeth and one nearly complete mandible with all the cheek teeth in situ. Another broken cranium without provenance was also referred to this species (Tong and Guérin, 2009). There is a gap between the earliest occurrence in the Pleistocene and Holocene records. The cranium (Fig. 4) once referred to Rhinoceros sinensis from the Yunxian Man Site (Echassoux et al., 2008 and Li and Feng, 2001) should be transferred to Dicerorhinus because of the presence of the following features: smaller incisors, an open subaural channel, a high and nearly vertical occipital face, a cranial dorsal profile with slight rather than great occipital elevation, and a zygomatic process of the maxilla arising from the same vertical level as the orbital rim rather than obviously posterior to it (as in Rhinoceros). However, the fossil cranium is slightly larger than the maximum dimensions of the extant D. sumatrensis provided by Guérin (1980).

1963b. Dicerorhinus yunchuchenensis Chow, p. 325–329, pl. I.

Diagnosis: A relatively large dicerorhine with massive and broad cranium. Nasals plow-like in outline, expanding at the nasal horn boss; tip of the nasals tapered and bifid, with a vertical groove at the middle; nasal septum partially ossified, and nasal opening very high. Upper incisors absent; cheek teeth brachyodont; entrance to medisinus wide and shallow on molars (modified from Chow, 1963b). The mandibular characters are not known because of the lack of fossil material.

Holotype: An almost complete cranium with left P2–M2 and right P4–M2 in situ (IVPP V2879) (Fig. 1, Fig. 2 and Fig. 3).

Type locality: Yuncu, Yushe County, Shanxi Province (Chow, 1963b); but the exact location is uncertain.

Horizon: The exact provenance of the material is uncertain (Chow, 1963b). The regional geological information shows that the fossils must have been recovered from Early Pleistocene deposits.

Remarks: This species is known from only a single locality. From the rough horn bosses, it seems that this animal had very strong nasal and frontal horns. Its extraordinarily expanded nasal bone distinguishes it from other species.

1978. Dicerorhinus lantianensis Hu and Qi, p. 38–39, pl. XI.

Diagnosis: Smaller than S. kirchbergensis and S. yunchuchenensis; tip of the nasal bone is sharply tapered; teeth are large (P2–M3 length is 250 mm); the protoloph and metaloph are parallel and are vertical to the long axis of the toothrow on P3–M2; the outer wall of the ectoloph is smooth; M3 has a metacone rib.

Holotype: An almost complete cranium of an old individual (IVPP V5413) (Fig. 1, Fig. 2 and Fig. 3).

Type locality: Gongwangling, Lantian County, Shaanxi Province (Hu and Qi, 1978).

Horizon: Late Early Pleistocene, about 1.15 Ma.

Remarks: This species is known from only a single locality. Its sharply tapered nasal bone makes it very different from other known Stephanorhinus species.

1931. Dicerorhinus choukoutiensis Wang, p. 69–76, pls. I–IV.

1941. Rhinoceros mercki (Jäger, 1939) - Teilhard de Chardin and Pei, p. 62–65, figs. 50–52b.

1942. Rhinoceros choukoutiensis (Wang, 1931) - Teilhard de Chardin and Leroy, p. 64.

1963a. Dicerorhinus choukoutienensis (Wang, 1931) - Chow, p. 62–70, pl. I.

1976. Dicerorhinus kirchbergensis (Jäger, 1939) - Ji, p. 62, pl. I.

1976. Dicerorhinus mercki (Jäger, 1939) - Jinniushan, p. 120–127, pl. I.

1979. Dicerorhinus choukoutienensis (Wang, 1931) - Chow, p. 236–258, pls. I–II.

1980. Dicerorhinus mercki (Jäger, Kaup, 1939, 1841) - Guérin, p. 623.

1986. Dicerorhinus kirchbergensis (Jäger, 1939) - Xu, 229–241, pl. I, figs. 3–4.

1996. Dicerorhinus mercki (Jäger, 1939) - Huang, p. 183–188, pls. XXX–XXXI.

1998. Rhinoceros sinensis (Owen, 1870) - Wu, p. 121–136, pl. I.

2002. Dicerorhinus mercki (Jäger, 1939) - Tong, p. 111–120, pls. 11–12, figs. 3.6–3.7.

Diagnosis: Very large in size (Guérin, 1980); high head; with nasal and frontal horns; nasal horn long; nasal septum partially ossified; nasal notch moved backward; anterior border of orbit and the posterior edge of palatine posteriorly positioned; plane of the occipital surface sub-vertical; subaural channel closed; mastoid inflated, the widest part of the occipital is at the level of the mastoid; mastoid not fused with the paroccipital process; the angle y (between opisthion + basion and palate) is less than 110°; upper and lower incisors absent; cheek teeth big and with smooth enamel surface; anticrochet and metastyle on upper cheek teeth absent; upper premolar highly molarized and quite hypsodont; molars subhypsodont; upper teeth much higher buccally than lingually, and thus extremely ectolophodont; ascending ramus slopes backward; long limbs and strongly concave limb joints indicate a graviportal locomotion (Fortelius et al., 1993, Groves, 1983 and Loose, 1975).

Referred specimens: The best material is an almost complete cranium with all the teeth in situ (IVPP V2682) from CKT Loc. 20 (Chow, 1963a) (Fig. 1, Fig. 2 and Fig. 3); quite a number of broken crania and mandibles, isolated teeth as well as postcranial bones were also reported from CKT Loc. 1 (Chow, 1979 and Wang, 1931) and CKT Loc. 13 (Teilhard de Chardin and Pei, 1941) as well as from Anping, Liaoning Province (Xu, 1986); few specimens come from the Nanjing Homo erectus site (Huang, 1996 and Tong, 2002). The most typical and richest specimens of this species were recovered in the Rhino Cave (named “Xiniudong” in Chinese) in Shennongjia, Hubei Province (Tong and Wu, 2010 and Wu, 1998).

Localities: At present, nearly 30 localities in China have been reported with fossils of S. kirchbergensis (Tong, 2002).

Horizons: From the Early to Late Pleistocene, but concentrated in the Middle Pleistocene (Fig. 5). The earliest occurrence is CKT Loc. 13 and the youngest record is the site at Harbin (20 ka). The most reliable youngest occurrence of this species in China is from the Rhino Cave in Hubei Province, a site of Early Late Pleistocene age that is rich in S. kirchbergensis fossils (Tong and Wu, 2010 and Wu, 1998).

Remarks: S. kirchbergensis is the most geographically and temporally widespread species of dicerorhines recovered in China. The taxonomy of this species has been in a state of confusion over the past few decades because the majority of the Quaternary non-Coelodonta rhinoceroses in North China were allocated to this species. Unfortunately, most of the fossil specimens are very poorly preserved. Recently, this species was placed in Dihoplus by Deng et al. (2011) without any discussion.