摘要
腕足动物Yunnanella和Nayunnella两属在我国分布很广 ,是晚泥盆世法门期重要的带化石之一。由于命名等问题 ,迄今 ,这两属的使用在国内外仍比较混乱。Sartenaer (196 1a ,196 2 )根据国际动物命名法规提出 ,YunnanellaGrabau ,192 3和NayunnellaSartenaer ,196 1两属的命名是有效的 ,它们的模式种分别是Yunnanellahanburii (Davidson ,185 3)和YunnanellasynplicataGrabau ,1931。YunnanellaGrabau ,1931是YunnanellaGrabau ,192 3的异物同名 ,YunnanellinaGrabau ,1931是YunnanellaGrabau ,192 3的同物异名。研究认为 ,Sartenaer(196 1a ,196 2 )的观点符合国际动物命名法规的优先原则 。
The Devonian brachiopod Yunnanella-Nanyunnella fauna is widely distributed in China, especially in South China. Since 1923, this fauna has been recorded in China by many authors (Grabau, 1923-1924, 1931; Schuchert et al., 1929; Tien, 1938; Wang, 1955; Wang et al., 1964, 1966; Zhang et al., 1959; Yang et al., 1977; Xu et al., 1978; Xu, 1978, 1979, 1980 ; Wang et al., 1982; Zhang et al., 1983; Zhang et al., 1983; Wang, 1984; Yang,1984; Yu et al., 1990; Ma, 1995). The genus Yunnanella was first reported by Grabau with two species Yunnanella synplicata Grabau and Y. hanburii (Davidson) (Grabau,1923, p.191,195). However, the monography on Devonian brachiopods of China written by Grabau was not published until 1931. In which, Grabau described Yunnanella as a new genus with a new species Yunnanella synplicata Grabau, 1931 as its type species and a new subgenus Yunnanellina with Rhynchonella hanburii Davidson,1853 as its type species (Grabau,1931, p.141,157). In two papers dealing with nomenclatural problems, Sartenaer (1961a, 1962) remarked that the nominal genus Yunnanella has been valid since 1923 when it was erected by Grabau and contained only one valid species Rhynchonella hanburii Davidson which was described by Davidson in 1853. The species Yunnanella synplicata Grabau, has neither description nor illustration in Grabau's book in 1923 and was not valid until 1931. Thus Y. hanburii had become an objective type species of Yunnanella although Grabau did not indicate the type species of Yunnanella in 1923. The subgenus Yunnanellina Grabau，1931 is objectively a synonym of Yunnanella Grabau，1923 because they have the same type species. Taken Yunnanella synplicata Grabau as the type species, Sartenaer (1961a) proposed a new genus Nayunnella as a substitute for the genus Yunnanella Grabau,1931. The genus Nayunnella differs from Yunnanella Grabau, 1923 in having costellae extending into plications arisen dependently near anterior and has been widely accepted since 1961. In the past decades, Yunannella and Nayunnella have been never reported in northern Xinjiang. They were reported only from southern Tianshan. Zhang et al.(1959, p.18) reported 2 indeterminate species (Yunnanella sp. and Yunnanellina sp.) at the lower part of the Upper Devonian Shashishan Formation in the southern Tianshan ［They have been revised as Nayunnella synplicata (Grabau) and N. abrupta (Grabau) respectively by Chen and Xu, 2000］. In 1983, Zhang Fengming described Yunnanella from the Upper Devonian Hazibulake Formation at Luntai and Turpan counties, southern Tianshan, with one species and one subspecies being established (Y. ovata Zhan and Y. triplicata turpanica Zhang). So traditionally, quite many geologists and palaeontologists in China are used to regarding the absence of Stringocephalus fauna and Yunnanella-Nayunnella fauna in North Xinjiang as one of the important evidences to divide the southern part of Xinjiang from the northern part. They thought that both the southern and northern parts of Xinjiang should belong to two different biogeographic provinces. Yunnanella-Nayunnella fauna is abundant in South China, especially in central Hunan. This fauna is often found in Upper Devonian(Lower to Middle Famennian). In most sections, the beds involved Yunnanella is often lower than the beds involved Nayunnella. Nayunnella is much more than Yunnanella in beds and thickness, quantity and diversity. In the prerecent study, very abundant specimens of the genus Nayunnella were found from the Shashishan section in South Tianshan. It is proved again that South China and South Tianshan had a close relationship during Late Devonian depending on the existence of abundant Nayunnella in the two regions. The specimens of the genus Yunnanella were first found from northern Xinjiang in 1973 and the exact location of the section yieding Yunnanella hanburii (Davidson) and Yunnanella sp. was confirmed at Tenglingsaka, about 5 km northwest of Yangzhuan, in Emin, northern Xinjiang in 2000. In North Xinjiang, only Yunnanella was found, but not any Nayunnella has been found until now. It is an opposite condition compared with South Xinjiang. It needs more evidences to prove what factors to cause these differences between South Xinjiang and North Xinjiang. According to the data availabe, the Yunnanella-Nayunnella fauna has been known from such provinces in China as northern Guangdong, Guangxi, eastern Yunnan, Hubei, Hunan, Jiangxi, Longmenshan of Sichuan, southwest Shaanxi, Gansu, southern Tianshan and western Junggar Basin of Xinjiang besides Kazakhstan and Novaya Zemlya, commonly occurring in the early and middle Famennian strata.
出处
《古生物学报》
CAS
CSCD
北大核心
2001年第2期229-238,共10页
Acta Palaeontologica Sinica
基金
国家自然科学基金! ( 4 9972 0 0 5 )
国家重点基础研究发展规划项目! (G2 0 0 0 0 7770 0 )资助
