Biostratigraphic and palaeoenvironmental significance of Campanian-early Maastrichtian (Late Cretaceous) ostracods from the Jiaozhou Formation of Zhucheng, Shandong, China

Ostracoda from the Santonian–Campanian (Upper Cretaceous) Nenjiang and Sifangtai formations, Songliao Basin, northeastern China

“…Szczechura and Błaszyk (1970) initially attributed this species to the genus Cypridea ; due to lack of typical Cypridea morphological characters, such as beak, alveolus, and cyathus, Szczechura (1978) reassigned it to Nemegtia Szczechura, 1978. However, the description provided by that work for Nemegtia renders it virtually identical to a previously created genus, Talicypridea Khand, 1977—which has been previously noted by Horne and Colin (2005) and Wang et al (2019) but never discussed on taxonomic remarks before. Talicypridea obliquecostae closely resembles Talicypridea neustruevae Khand, Sames, and Schudack, 2007, but the latter has a more ovate outline in lateral view, weakly developed spines on the lip, and a unique wavy ornamentation (these ornamentation elements were considered by Sames [2011c] of lower taxonomic significance, however).…”

“…Wu et al (2014) constrained the age of the Sifangtai Formation between 76.077 and 72.86 Ma (middle–late Campanian) on the basis of magneto-, cyclo-, and biostratigraphy; additional palynomorph data suggest a late Campanian age (Yoshinoda et al, 2017). Furthermore, there is a correlation between the ostracode faunas of the Sifangtai and Minhe, Qingyuangang, and Jiaozhou formations, which have been previously assigned to the Campanian–Maastrichtian (Liu et al, 2004; Xi et al, 2019; Wang et al, 2019). These data, other than being supported by the species found in the present assemblages, allowed a refinement in the distribution of 13 of the 14 taxa (which were previously recorded in the Songliao Basin) from Late Cretaceous to a Santonian–Campanian distribution (see the “Systematic paleontology” section for a summarization).…”

“…Mongolia: Ömnögovi Province, Gobi Desert, Nemegt and Altan (“Ula IV”) mountains, and Bugeen Tsav and Nogon Tsav localities; Nemegt Basin, Nemegt Formation, Upper Cretaceous (Galeeva, 1955; Szczechura, 1978). China: Jilin Province, Baicheng City, Songliao Basin, Fulongquan, Mingshui and Sifangtai formations, Upper Cretaceous (Hao et al, 1974; DOFEAD, 1976; Hou et al, 2002; Ye et al, 2002); Qinghai Province, Minhe Formation, Upper Cretaceous (Hao, 1988); and Shandong province, Jiaolai Basin, Jiaozhou Formation (Wang et al, 2019). In the present work, Member 1 of the Nenjiang Formation and the Sifangtai Formation, lower Santonian–middle Campanian, Qianjiadian Town, Tongliao City, Inner Mongolia, northeastern China.…”

“…China: Heilongjiang Province, Daqing City, and Jilin Province, cities of Fuyu and Shuangliao and Changling County; Songliao Basin, Nenjiang Formation; Da'an City, Sifangtai and Mingshui formations, Upper Cretaceous (Hao et al, 1974; DOFEAD, 1976; Hou et al, 2002; Ye et al, 2002; Qu et al, 2014; Wang et al, 2019). In the present work, Member 1 of the Nenjiang Formation, lower–middle Santonian, Qianjiadian Town, Tongliao City, Inner Mongolia, northeastern China.…”

“…Mongolia: Ömnögovi Province, Gobi Desert, Altan (“UIa IV”) mountains and Bugeen Tsav, Nogon Tsav, and Tsagan Khushu localities, Nemegt Basin, Nemegt Formation, Upper Cretaceous (Szczechura, 1978). China, Upper Cretaceous: Jilin Province, cities of Baicheng, Tongyu, and Shuangliao; Heilongjiang Province, Lanxi County, Sifangtai and Mingshui formations; Hubei Province, Dangyang city and Paomagang village, Yuyang and Jianglin formations; and Shandong Province, Laiyang City, Wangshi Formation, and Jiankou village, Jiaozhou Formation (DOFEAD, 1976; Hou et al, 1978, 1982, 2002; Hao et al, 1983; Ye et al, 2002; Wang et al, 2019). In the present work, Sifangtai Formation, middle–upper Campanian, Qianjiadian Town, Tongliao City, Inner Mongolia, northeastern China.…”