Conifers From The Lower Cretaceous Changcai Formation In The Yanbian Area, Jilin Province

The late Mesozoic terrestrial strata are well developed in theYanbian area of eastern Jilin Province, China. It yields abundant fossil flora and fauna, being an important part in the research on the Mesozoic biota and non-marine deposits in China. The Lower Cretaceous Changcai Formation (sensu lata) is distributed mainly in Laotougou and Tuntianying of Longjing County, Changcai, Fudong, Nanyang, Tushanzi, Songxiaping and Dajinchang of Helong County, eastern Jilin Province. It is an important coal-bearing strata consisting mainly of gray sandstone, sandy conglomerate and gray-green conglomerate intercalated with black shale, carbonaceous mudstone and coal beds, yielding abundant fossil plants.Since 1950's, twety five species of eleven genera of conifers have been recorded from the Changcai Formation in the Yanbian area (Yang Xuelin,1959; Zhou Zhiyan et al,1980; Zhang Wu et al, 1980; Bureau of Geology and Mineral Resources of Jilin Province, 1988,1992; Shang Qinghua,1992). Among these species, only a few were described systematically based on the gross morphology; and no species were did anatomic research on the cuticle of leaves or reproductive organs.Based on the field investigation and great collection of fossil plants, the author identified and systematically described the conifers from the Lower Cretaceous Changcai Formation, discussed their characters, and compared them with those from related floras (abroad and domestic). Some achievements are as follows:1. Nineteen species of ten genera of conifers (including one new species and three undeterminated species) were identified from the early Cretaceous coal-bearing deposits of the Changcai Formation in the Yanbian area, Jilin Province. They are Pityocladus yingchengensis Chang, Pityocladus sp., Pityophyllum lindstroemi Nathorst, Pityophyllum longifolium (Nath.) Moeller, Pityophyllum nordenskioldii Heer, Pityostrobus liufangziensis Yang, Sphenolepis kurriana (Dunker) Schenk, Elatides curvifolia (Dunker) Nathost, Elatides helongensis Sun et Zhao (sp. nov.), Elatides sp. 1, Elatides sp. 2, Cephalotaxopsis haizhouensis Shang, Cephalotaxopsis fuxinensis Shang, Taxus intermedius (Hollick) Meng et Chen, Podozamites lanceolatus (L. et H.) Braun, Podozamites eichwaldii Schimper, Elatocladus manchurica (Yokoyama) Yabe, Elatocladus submanchurica Yabe et Oishi and Pagiophyllum triangulare Prynada.2. Among them, four species of four genera were made cuticle observation successfully. They are Pityostrobus liufangziensis Yang, Elatides helongensis Sun et Zhao (sp. nov.), Cephalotaxopsis haizhouensis Shang and Pagiophyllum triangulare Prynada. This is significant in the fossil conifers taxonomy.3. The conifers from the Changcai Formation composed of Coniferales, Taxales, Podozamitales and incertain conifers is characterized by the diverse Pinaceae (3 genera and 6 species) and Texodiaceae (3 genus and 7 species), and by the abundant Cephalotaxopsis. Since the scale-like leave conifers such as Brachyphyllum, Frenelopsis and Pseudofrenelopsis are not found, the present coniferous flora shows the character of north subtropical-temperate zone in the early Cretaceous Siberian-Canadian Phytofloristic Realm (Vachrameev B.A., 1964, 1988), or in the Boreal Realm (Sun Ge et al, 1995), being an important part of the warm and humid vegetation.4. The conifers from the Changcai Formation can be correlated with those from the northern and northeastern China (such as Jiutai and Yingcheng in Jilin Province, Fuxin and Tiefa in Liaoning Province, Shuangyashan in Heilongjiang Province, Hailar, Huolinhe and Guyang in Inner Mongolia), from Russia (such as Bureya, Southern Primorye Sakhalin, West Priokhotie, Omsukchana), and from North America (western Canada).