放射虫化石及地体对比研究

A MORPHOLOGICAL ANALYSIS ON INTRASPECIFIC VARIATION OF CERVAVITUS NOVOROSSIAE

放射虫是一种分布广、区域对比作用大、具有硅质骨格和外壳的远洋、浮游、单细胞微体动物，放射虫化石研究的进展，作为新的地层时代的鉴定标志，在对构造活动带的研究中发挥了重要作用。北美西部及环太平洋构造带的放射虫研究成果，明确了这些地区的地层层序和构造发展史，从而表明，放射虫化石已不单单是古生物学的研究对象，而是地层层序学和构造地质学研究的一个不可缺少的重要方法之一。在对中国东北那丹哈达地体和日本美浓地体的对比研究中，放射虫化石的产出与对比研究，对分析研究两地体的构造发展史起了关键性的作用。

Cervavitus novorossiae , a Late Neogene cervid is a little smaller than the sika ( Cervus nippon ). It is a holometacalpi form that links the telemetacalpi and pleisiometacalpi forms. Its antlers are generally thorn like and three tined (occasionally four tined). Due to its particular position in systematics and phylogeny of the Cervidae, the study of morphological variation within the species is very important to understanding of cervid evolution. The present paper makes a study on the morphological variation in antlers and cheek teeth of the species found in North China. All the materials studied are housed in Institute of Vertebrate Palaeontology and Palaeoanthropology, Academia Sinica and Tianjin Natural History Museum. I MORPHOLOGICAL VARIATION ON FRONTAL APPENDAGES Four kinds of variations on the frontal appendages are generally observed: 1.1 Annual variation The antlers of cervids are annually deciduous, and therefore different from one year to another. The most common variation on antlers is caused by their annual growth. This variation is easy to identify in Cervavitus novorossiae. 〖ST10.HZ]1.2 Environmental variation The development of antlers needs enough nourishment and minerals. When the food source suffered such natural disasters as aridity, fire, inundation, etc., the antler growth will be stagnated and poorly developed. The abundance of minerals in different areas also influences antler growth. For example, the palmation of antlers is stronger in the species from Taraklia, Russia than in those from North China because of geographical and environmental differences. 〖ST10.HZ]1.3 Pathological variation Diseases and injuries cause disturbance to endocrine and consequently deformation to the growing antler. To castrate a male deer during antler growing season will stop the growth of antlers. But the latter will develop again with injection of male hormone. The “Platycemas infans” Teilhard et Trassaert (Fig.1 in Chinese text of this paper) is very likely an antler of Cervavitus novorossiae formed during testicles' injury. The genus and species were erected by Teilhard and Trassaert (1937) based on only one specimen found in Yushe Basin, North China, which bears a resemblance to Stephanocemas Colbert (Teilhard and Trassaert, 1937). But no further specimens of the genus and species have been discovered in later investigations (1938-1994). The only specimen of “ Platycemas infans ”, an antler, is palmated sagittally and its three tines are very short, just like those in the early growing antler of an adult deer both in form and in size. While the antlers of all Stephanocemas are palmated transversally with more than three tines. Cervavitus novorossiae is habitually in large herds; the occasional disease and injury in some unfortunate individuals are not surprising and difficult to imagine.Since hundreds of fossil antlers have been collected in Yushe Basin, it is not surprising that one or more of them are pathological specimens. 〖ST10.HZ]1.4 Random variation The first segment of main beam varies in length from one individual to another. The maximal difference observed between short segments and long ones is 210 mm. The bifurcation angles also display large variations, with a maximal difference of about 70 degrees. The “ Procapreolus latifrons ” of Schlosser (1924) is morphologically very similar to Cervavitus novorossiae. Teilhard and Trassaert (1937) had grouped some of the Procapreolus identified by Zdansky (1925,1927) in Cervavitus novorossiae. The present authors share the same view with Teilhard and Trassaert that the morphological difference between Procapreolus latifrons and Cervavitus novorossiae is intraspecific and is of random variation. 2 MORPHOLOGICAL VARIATION ON THE CHEEK TEETH The specimens are grouped in six samples for analysis: Sample A includes the specimens from Locality 35 (Xin'an, Henan) and from Lushi, Henan; Sample B includes those from Locality 49 (Baode, Shanxi); Sample C includes those from Localiti