Huang, Z. X.; Zeng, X. L. (1984). The early Early Permian (Longlinian Stage) fusulinid fauna from Longlin, Guangxi. Earth Sci.-Jour., Wuhan Coll. Geol. 26(3): 11-24.

290445

Huang, Z. X.; Zeng, X. L.

1984

26(3): 11-24

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The present paper is concerned primarily with early Early Permian fusuliaids of Longlinia stage. Longlinian is a new stratigraphic unit between the underlying Pseudoschwagerina zone of Mapingian and the overlying Miscllina zone of Chixian. This unit contains abundant fusulinids forming the Pamirina (Nanpanella)-P. (Pamirina)-Nagatoella (Darvasites) Fauna: 13 genera, 4 subgenera, 27 species, including 2 new genera, 1 new subgenera, 12 new species and 3 undeterminable (table 1). This fusulinid fauna is marked by the following features. (1) This fauna belongs to the Tethyan realm for similar fusulinids are known in many localities of Tethys; such as Darvas, N. Pamir, Transcaueasu of USSR; Taea of Yugoslavia; Kitakami Massif of Japan; Shenxi, Guizhou, Qinghai, Xinjiang of China. However new endemic species make up about 50% of the fauna. Besides a few genera of the same fauna are also know from Nevada, New Mexico, and California of U.S.A..Hence the American fauna is more or less related to our Longlin fauna (fig.l). (2) The genera Pamirina (Nanpanella)-P. (Pamirina)-Misellina (Brevaxina) form a phyletic lineage. It has been pointed out that P. (Pamirina) descends from Misellina (Leven, 1970), whereas the P. (Nanpanella) with more primitive characters occurs in a horizon distinctly lower than P.(pamirina), so that, P. (pamirina ) might be considered also a descendant of P. (Nanpanella). It follows that the source of the High-fusulinids can be traced back not only to P. (Nanpanella), but also to the Misellina fauna of Chixian age. On the basis of fusulinid phylogeny and the stratigraphic distribution of the fusulinids the Pamirina-Nagatoella (Darvasites) zone may be divided into two sub-zones: P. (Nanpanella) laxa and P. (Pamirina) chinlingensis (fig.2). (3) The family Staffellidae includes such genera as Pseudoreichelina, Pamirina (Pamirina), P.(Nanpanella), which are characterized by finely alveolar keriotheca; in Schwagerinidae, the rise of such genera as Parafusulina ( Skinnerella ), Nagatoella ( Darvasites ), Biwaella, Longlinella, Eochusenella, Paraschwagerina, and many new species of Pseudofusulina, suggests that the fusulinid fauna entered an important epoch of change and development. As stated above, the sharpest break between the fauna of Longlinian and Pseudoschwagerina-Zellia fauna of Mapingian suggests the beginning of a new period of geological history the Permian. In this paper 2 new genera, 1 new subgenus and 11 new species are described. The description of the new genera is given as follows. Genus Longlinella Huang gen.nov. Type species: Longlinella longsangensis Huang gen. et sp. nov. Shell minute, inflated fusiform or subcylindrical. Mature shell having 4-5 loosely coiled volutions. Spirotheca thin, composed of a tectum and a thin alveolar keriotheca. Septa plane. Chomata generally lacking or very weak. Axial filling not present. Tunnel singular. Proloculus large. Remarks: This new genus is similar in many respects to Oketaella, but the latter has massive chomata, thin axial filling and thick spirotheca . Genus Eochusenella Huang gen. nov. Type species: Eochusenella longsangensis Huang gen. et sp. nov. Shell of medium size, inflated fusiform with bluntly pointed poles. Mature shell having 8-10 volutions. A distinct juvenarium of a few very thin-walled and tightly coiled volutions, the outer volutions loosely coiled. Spirotheca composed of a tectum and alveolar keriotheca. Septa regularly fluted throughout the length of the shell, except in the innermost portion where they are plane. Septal fluting widely spaced and confined to the lower part of the septa. Chomata small, present in all whorls, except in the outermost 1-2 whorls. Tunnel singular. Axial filling very thin or absent. Proloculus spherical.

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