4 species recognized in genus Rhinoceros, including: Rhinoceros sinensis Owen, 1870. Synonyms: R. plicidens, R. simplicidens. Pleistocene of southwestern China. At this place it might be well to consider briefly two Pleistocene species of Rhinoceros, Rhinoceros sinensis and Rhinoceros sivalensis, both known from considerable suites of materials from China and India, repectively. Rhinoceros sinensis is a large species, almost as big as the modern Indian rhinoceros, but interesting in that it shows a combination of the characters that distinguish R. sondaicus and R. unicornis. Thus, in spite of its large size, Rhinoceros sinensis seemingly had a rather small horn carried on a pointed horn boss, as in the Javan rhinoceros. Since the back of the skull is not well preserved in this species, nothing can be said about the diagnostic characters of the cranial and basicranial regions. However, the cheek teeth are interesting in that they are hypsodont, more so than the teeth of Rhinoceros sondaicus, less so than those of Rhinoceros unicornis, they have the parastyle buttress as in R. sondaicus but not so prominent, the ectoloph is less sinuous than in R. sondaicus but not so flattened as in R. unicornis, while the crochet and crista, although well developed (the latter often being reduplicated), do not join to enclose a medifossette as in R. unicornis. Thus it seems evident that Rhinoceros sinensis is a form of rather intermediate position between the two living species.
4 species recognized in genus Rhinoceros, including: Rhinoceros sivalensis Falconer and Cautley, 1847. Synonym: R. palaeindicus. Pleistocene of the Siwalik Hills of India. Rhinoceros sivalensis, on the other hand, would seem to be rather close to Rhinoceros unicornis. The extinct form is a large species, showing in the structure of the skull (the large horn boss, the deep saddle in the cranial profile, the forwardly inclined occiput, the depth of the skull and the like) a close approach to the modern Indian form. The cheek teeth in this species are characterized by a rather flat ectoloph but by a certain retention of the parastyle buttress, while the crochet and crista have not reached that stage in developement where they join to enclose a medifossette.
Four species recognized in genus Rhinoceros, including: Rhinoceros unicornis Linnaeus, 1758. Type of genus. Synonyms: R. indicus, R. asiaticus, R. stenocephalus. Pleistocene and Recent of India. Now very limited in range.
Four species recognized in genus Rhinoceros, including: Rhinoceros sondaicus Desmarest, 1822. Synonyms: R. javanicus, R. inermis, R. nasalis, R. floweri. Possibly Pleistocene (of Borneo) and Recent of the Sundarbans, eastern Bengal, Assam, Burma, Malay Peninsula, Sumatra and Java.
In the first place, it might be well to indi- cate the limits of the genus Rhinoceros. This genus has been used, particularly by palaeontologists, to include a great number of species ranging in age from the Pliocene through the Pleistocene and into Recent times. Indeed, during the early history of vertebrate paleontology it was the practice to designate almost every fossil rhinoceros of post-Oligocene age as Rhinoceros, since in those days students of fossils naturally were but little concerned with the critical limitations for genera and species that have developed with the refinement of the science. Obviously this is wrong and has been so recognized with the increasingly detailed studies that have been made in later years on fossil vertebrates. Consequently, at the present time most of the fossil species formerly designated as Rhinoceros have been allocated to other genera, and the genus has thus become strictly limited according to the evidence of its anatomical characters, which, as far as the osteology of the skull and the dentition are concerned, are as follows: 1. Expansion of the nasal bones into a boss or eminence, upon which is borne the single nasal horn. 2. Incisors present, and of large size. 3. Skull short, with occipital plane inclined forward. 4. Auditory meatus closed inferiorly by fusion of the post-tympanic and the post-glenoid processes. 5. Cheek-teeth sub-hypsodont. Upon the basis of the above limitations, the genus Rhinoceros includes four good species, two of which are of recent age, and two of which are extinct. There are other fossil species of doubtful validity which need not be considered at this place. The four species with which we are concerned are: Rhinoceros unicornis Linnaeus, 1758. Type of genus. Synonyms: R. indicus, R. asiaticus, R. stenocephalus. Pleistocene and Recent of India. Now very limited in range. Rhinoceros sondaicus Desmarest, 1822. Synonyms: R. javanicus, R. inermis, R. nasalis, R. floweri. Possibly Pleistocene (of Borneo) and Recent of the Sundarbans, eastern Bengal, Assam, Burma, Malay Peninsula, Sumatra and Java. Rhinoceros sivalensis Falconer and Cautley, 1847. Synonym: R. palaeindicus. Pleistocene of the Siwalik Hills of India. Rhinoceros sinensis Owen, 1870. Synonyms: R. plicidens, R. simplicidens. Pleistocene of southwestern China.
