关于柄杯鹿亚科(Lagomerycinae)的系统位置

柄杯鹿亚科的系统位置争论已久。争论的焦点是它们属于鹿科中的亚科还是麒麟鹿超科。经过对头骨和头后骨骼形态特点的研究和用扫描电镜检查角的结构显出柄杯鹿具有原始的角,而这种原始的角与后期鹿类的角柄同源。因此认为柄杯鹿科是鹿类中独立的一分支。

ON THE SYSTEMATIC POSITION OF THE LAGOMERYCINAE

The family Lagomerycidae,established by Pilgrim in 1941,includes three genera:Lago- meryx Roger,1904,Procervulus Gaudry,1878 and Climacoceras MacInnes,1936.The affinity and systematic position of the family has been disputable for a long time.They were consi- dered as:I)a subfamily of the family Cervidae(Teilhard de Chardin,1939;Crusafont Pairo, 1952;Viret,1961;Vislobokova,1983);2)a family of the superfamily Giraffoidea(Pilgrim, 1941;Simpson,1945;Young,1964);3)a synonym of the Palaeomerycidae of the superfamily Giraffoidea(Stirton,1944;Withworth,1958;Hamilton,1973);4)the Muntiacini(Chow,Shih, 1978). The genus Lagomeryx was defined by Roger(1904)based on a species of Palaeomeryx Meyer,1834 with non-deciduous antlers.The type species is Palaeomeryx meyeri Hofmann, 1893 from the Middle Miocene of Goriach,Austria.Some investigators casted doubts on the validity of the genus Lagomeryx,considering it to be a synonym of the genus Palaeomeryx (Withworth,1958;Hamilton,1973). The genus Procervulus was established by Gaudry(1878),based on the type species Cervus aurelianensis Gervais,1859 from Pont-Levoy,France.Some students thought that Procervulus was close to cervids(Zittel,1925;Ginsburg,Crouzel,1976). The genus Climacoceras from the Middle Miocene of Kenya was grouped by Maclnnes with the Cervidae.MacInnes identified the type species Climacoceras africanus MacInnes,1936 from Maboko as a true deer.Hamilton(1978)placed Climacoceras in the giraffoid family Climacocervidae.The other species C.gentryi Hamilton from Fort Ternan was described to possess a bilobed lower canine(Hamilton,1978). The definition of the Palaeomerycidae was based on the investigation of Ginsburg,Heintz (1966)and Qiu,Yah,Jia,Sun,1985).Ginsburg and Heintz(1966)showed,that the genus Palaeomeryx has ossicones of definitely giraffid type.The discovery of the complete skeleton of Palaeomeryx tricornis from the lake deposits of the Middle Miocene in Shanwang,Linqu,Shan- dong,shows that Palaeomeryx had more derived characters with giraffids than with cervids. They have only some plesiomorphic characters similar to those of the last one(Qiu,Yan,Jia, Sun,1985).Some progressive features,such as a closed metatarsal groove,could be derived through parallel evolution in these two groups.The palaeontological evidences show that this feature,characteristic of cervids,derived independently in different groups of the Ruminantia and,in particular,in the Protoceratidae,Leptomerycidae and Moschidae.The studies of the Chinese paleontologists gave convincing evidence to indicate that the Palaeomerycidae is a se- parate branch of ancient giraffoids. The structure of the antler of the Lagomerycinae differs essentially from the structure of the ossicones of Palaeomeryx:firstly,the boundary demarcating the frontal bone and ossicone is absent in the Lagomerycidae,but very distinct in Palaeomeryx and giraffids,and,secondly, the structures of the antlers of the Lagomerycinae and Palaeomerycidae are quite different.The examination of the antler structure with the SEM shows that it is close to the structure of the pedicle and non-deciduous antler(pl.I)of the deer. The new data for more precisely defining of the position of lagomericines were from complete skeletons of Lagomeryx colberti(Young,1937)found in Shanwang.The skull of L.colberti is closely comparable to that of representatives of the Dremotheriinae,the most primitive subfamily of the Cervidae,known from the Middle Oligocene.Ginsburg and Heintz (1966)considered dremotheriids ancestral to the Cervidae and Giraffidae.It was considered to be ancestral only to the Cervids(Vislobokova,1983).Lagomeryx possesses the following features resembling those of dremotheriins in having:1)a sagittal crest;2)a powerful occipital crest; 3)a long low braincase;4)morphological peculiarities of meatus temporalis(postglenoid process does not connect the petrosal bone with isthmus);5)a short facial part of the skull;6)dif- ferent position of the anterior edge of the orbit on the level of M~2;7)a praeorbital fossa;8) a fissura ethmoidalis;9)a cone-shaped pit for musculus obliquus ventralis;10)a short prae- maxillary bones;11)an inclination of the lower wall of the orbit insides;12)an inconstant presence of the first lower P_1(it is developed,for example,in specimen no.700023,belonging to a female,and in specimen,described by Teilhard de Chardin(1939,fig.5);13)saber-like upper canines in male;14)simple,faintly molarized premolars,but already of cervid type; 15)brachyodont molars;16)the presence of Palaeomeryx fold in the lower molars;17)a closed metatarsal gully;18)reduced,but complete lateral metacarpals.Some of these features (1—5,10,15)are primitive,possibly,derived from distant ancestors,the others seem to be derived from dremotheriines. Lagomeryx also exibits advanced derived features which are present among other cervids (Muntiacinae,Cervinae,Alcinae,Odocoileinae).They are:1)two lacrimal orifices in the lacrimal bone(the upper one on the orbital rim,and the lower one inside the orbit,specimen no. 700025).Drernotherium has one orifice inside the orbit.According to Leinders and Heints (1980),the lacrimal duct of cervids open into two orifices on the rim of the orbit since the Middle Miocene and Heteroprox Stehlin,1928 has already had such position of lacrimal ori- fices;2)the presence of antlers as cranial appendages.Advanced feature seems to be a posi- tion of the posterior border of nasal bones in front of the orbits(it is characteristic for the Muntiacini and Cervini);and besides,some elongation of the external auditory meatus as com- pared with that in dremotheriines(the external auditory meatus is of moderate length in Hyd- ropotes and Muntiacini). The structure of meatus temporalis(skull no.700026)is more primitive,than in that of the Muntiacinae.It does not agree with the viewpoints of Chow and Shih(1978),including lagomericines in the Muntiacini.The Muntiacinae,as well as the Cervinae,possessed the bone isthmus which connected the postglenoid process with the petrosal bone and medially limited the foramen of meatus temporalis. Thus,it is reasonable to believe that the Lagomerycidae was quite probably a unique branch of cervids,as Teilhard de Chardin(1939)suggested.These cervids had primitive antlers analogous to pedicles of the later deer. As all other subfamilies of cervids,they showed evolutionary trends towards the complica- tion of antlers and dental system adapted to a nutrition of more coarse forage with an admix- ture of grass.Skeleton characters of the Lagomeryx colberti also suggest that they were adap- tive to jumping.They appear to have lived in overgrowth of the bushes and the woodland with low thickets near the water.The morphology of ph III(long,narrow,with a narrow heel) shows they are adapted to fairly damp ground.