江西晚石炭世晚期及早二叠世早期的四射珊瑚

LATE LATE CARBONIFEROUS AND EARLIEST PERMIAN RUGOSE CORALS FROM JIANGXI

记述江西彭泽、于都、乐平、玉山、崇义及上高等地上石炭统船山组和下二叠统栖霞组的四射珊瑚16种,其中船山组有11属12种(包括8新种、1未定种),栖霞组有3属4种(包括3新种、1未定种).根据珊瑚化石的分布规律,将船山组的珊瑚建立2个组合,并与有关地区的珊瑚组合进行了对比.通过对这些珊瑚形态构造特征的剖析,文章还探讨了晚石炭世晚期及早二叠世早期本区珊瑚的生态特征.

This paper deals with the rugose corals obtained from the Upper Carboniferous Chuanshan Formation and the Lower Permian Chihsia Formation (Member I) in Pengze of Leping County, Yudou of Shanggao County, Yushan and Chongyi Counties, Jiangxi Province, which contain 14 genera and 16 species (including 11 new species). I. Protoivanovia-Fomichevella-Arctophyllum-Pseudocarniaphyllum Assemblage, including Protoivanovia penzeensis Zhu, P. dupliformis X. Y, Fomichevella hoeli (Holtedahl), F. longiseptata sp. nov., Arctophyllum jiangxiense sp. nov., Pseudocarniaphyllum jiangxiense sp. nov., Amygdalophyl- loides multiseptatus X. Y, Carniaphyllum gortanii Heritsch, Timania sp. and Chuanshanophyllum sp. Among these corals, Protoivanovia occurring in the lower part of Chuanshan Formation of Anhui and Jiangsu and the Taiyuan Formation of Shanxi was also found in Moscovian and Gzhelian of the Moscow Basin, but the present Protoivanovia penzeensis Zhu is similar to P. lingchuanensis Zhao (1987) from the Taiyuan Formation of Shanxi. Fomichevella which is widely distributed in the Upper Carboniferous of former USSR, is seen in the Dingshan Formation of Jiangsu, the Maping Formation of Guangxi and the Upper Carboniferous of Qinghai in China, but Fomichevella hoeli (Holtedahl) seen in the Gzhelian Fusulina limestone of Spitbergen is first found in China. Arctophyllum is widely distributed in the Upper Carboniferous of northern Xinjiang, Yushu of Qinghai, western Guizhou and southern Jiangsu, but A. jtangxiense sp. nov. is similar to A. intermedium (Toula) (Fedorowski, 1977) from the Teguliferina bed of the Moscow Basin and Gzhelian of Spitsbergen. Pseudocarniaphyllum is known to occur in the Maping Formation of Guangxi and the Chuanshan Formation of Jiangsu, but P. jiangxiense sp. nov. is similar to P. paraorientale X. Y(1977, 1980) from the Chuanshan Formation of Jiangsu. Arnygdalophylloides is widespread in the Upper Carboniferous, but A. multiseptatus X. Y in this paper is also seen in the Chuanshan Formation of Jiangsu. Carniaphyllum is known to occur in the Upper Carboniferous of Spitsbergen, while Chuanshanophyllum is known to occur in the Chuanshan or Maping Formation of Jiangsu, western Guizhou and northern Guangxi. It is obvious that some components of this assemblage can be related to those from the Chuanshanophyllum Zone of southern Jiangsu or from the Upper Carboniferous of former USSR and Spitsbergen. II. Parawentzellophyllurn-Lytvophyllum-Koninckophyllum-Stereostylus Assemblage, including Parawentzellophyllum lepingense sp. nov., Eokepingophyllum acolumellum sp. nov., Nephelophyllum mixocolumellum sp. nov., Peiraphyllum anguipore sp. nov., Lytvophyllum flexuosum sp. nov., L. sp., Koninckophyllum caninophylloidea X. Y, Koninckocarina wenhuashanensis X. Y and Stereostylus annae Jeffords. As a zonal fossil for the upper part of the Chuanshan Formation in southern Jiangsu (X. Y?, 1980), Parawentzellophyllum is most important, while P. lepingense sp. nov. is similar to P. dantuense X. Y (1980) from the Chuanshan Formation of southern Jiangsu. Eokepingophyllum is known to occur in the Lytvophyllum mengi Subzone of the Chuanshan Formation in Yixing, Jiangsu, but the present horizon containing Eokepingophyllum is higher than that in Jiangsu. Nephelophyllum is seen in the Maping Formation of western Guizhou and the Upper Carboniferous of Qinghai, but it was also found in the Lower Permian of Zhangyi, Yunnan and Qa?dam Basin, Qinghai. Peiraphyllum is a component from the Parawentzellophyllum Zone of the Chuanshan Formation in southern Jiangsu, but it was also found in the lower part of the Lower Permian in western Guizhou, and therefore its age may be assigned to late Late Carboniferous-Early Permian.As an important component in Assemblage II, Lytvophyllum also appeared in the lower part of the Lower Permian, of Ural, the former USSR and southern Sichuan; some species occur in the Chuanshah Formation of southern Jiangsu and southern Anhui, but the present L. flexuosum sp. nov. is similar to L. insolium X. Y? (1980) of Jiangsu. Koninckophyllum is widespread in the Carboniferous of Europe and Asia, and can be seen in the upper part of the Upper Carboniferous in Jiang su, Hunan and Guangxi of China. Koninckocarinia wenhuashanensis X. Y? is seen in the Chuanshah Formation of southern Jiangsu; Stereostylus annae Jeffords seen in the Upper Carboniferous of Kansas, USA., is first found in China. According to the above-mentioned features, Assemblage II may be comparable with the Parawentzellophyllum Zone of southern Jiangsu, but it differs in the absence of Akagophyllum and Ke- pingophyllum. It is also related to the Late Carboniferous rugose corals of the Moscow Basin, Ural and Kansas. In addition, Parawentzellophyllum, Lytvophyllum, and Stereostylus of Assemblage II are absent in Assemblage I, while Protoivanovia, Fomichevella, Arctophyllum and Pseudocarniaphyllum of Assemblage I are absent in Assemblage II. From these it can be seen that both assemblages are composed of massive, fasciculate and solitary corals. The massivecorals include Protoivanovia, Parawentzellophyllum, Eokepingophyllum, Nephelophyllurn and Peiraphyllum, accounting for 31.2% of the total genera; the fasciculate corals include Fomichevella and Lytvophyllum, accounting for 1.25%; and the solitary corals include Arctophyllum, Pseudocarniaphyllum, Amygdalophylloides Carniaphyllum, Chuanshanophyllum, Timania, Koninckophyllum, Koninckocarinia and Stereostylus, accounting for 67.55%. All massive corals developed peripheral cystose. Among them, Protoivanovia and Eokepingophyllum only developed or underdeveloped a median plate in axis part while Parawentzellophyllum, Nephelophyllum and Peiraphyllum developed median plate, radial lamellae and tabellae. However, all of them didn't develop tertiary septa. It is shown that these massive corals didn't reach a higher degree in the development of rugose corals. In the fasciculate corals, Fomichevella belongs to zweizoner and Lytvophyllum to zweizonerdreizoner. The larvas of these corals are developed from lateral parts of adult corallites. Sometimes, waves lashed the corallites, causing the larvas to separate from the adult corallites and grow independently. This is why we often found dispersive corallites of Fomichevella and Lytvophyllum in stratigraphic sections. All the solitary corals belong to the simple or complex dreizoner, except for Arctophyllum to the dweidoner. The simple dreizoner consists only of a simple stereocolumella or a plate-columella, such as in Timania, Koninckophyllum and Koninckocarinia, while the complex dreizoner consists of a median plate, radial lamellae and tabellae. Among them, the cardinal quadrant septa of Arctophyllum and Timania are thickened; the stereocolumellae of Carinthiaphyllum and Koninckocarinia are connected with a septum and the complex syncolumellae of Carniaphylm, Pseudocarnia phyllum, Chuanshanophyllum and Amygdalophylloides are composed of a median plate, radial lamellae and tabellae. The structure of corals has an effect on body reinforcement. From their morphology it can be seen that they were inhabitants in an ecological environment of slightly shallow water with high energy. Monothecalis and Lasmophyllum are early Early Permian members, the former being massive corals with a lot of cystose and the latter fasciculate corals with septa extending to the center and connecting with each other. Both also lived in an environment of shallower water. DESCRIPTION OF NEW SPECIES Arctophyllum jiangxiense sp. nov. (Pl. I, figs. la, b; text-fig. 2) Description Solitary coral measuring 20 mm in diameter. Septa of two orders, 34+34 in number, fibronormal in fine skeletal structure; major septa with a length of about 4/5 the radius of corallum, 20 in number and strongly thickened in cardinal quadrant, but only 14 in number artd very thin in counter quadrant; minor ones very short, thread-like; cardinal septum shortened. Cardinal fossula distinct. Dissepimentarium very narrow, composed of irregular herringbone dissepimerits. Tabulae complete and horizontal or fiexuous, with 4-5 of them occupying a space of 5mm. Remarks In the strongly thickened septa in cardinal quadrant, this species resembles Arctophyllum intermedium (Toula) (Fedorowski, 1975), but the latter has wider cardinal fossula, less strongly thickened septa and some counter quadrant septa. Horizon and locality Upper Carboniferous Chuanshan Formation; Jingzishan, Pengze County, Jiangxi. Fomichevella longiseptata sp. nov. (Pl. II, figs. 6a, b; text-fig. 3) Description Corallum fasciculate; corallites 13mm in diameter. Septa of two orders, 30+30 in number, slightly thickened in cardinal quadrant, fibronormal in fine skeletal structure; major septa with a length of about 1/3 the diameter of corallites, with some of them extending to the center and connected with each other; minor ones very short, about 1/5 as long as the major ones; cardinal septum shortened. Cardinal fossula distinct. Dissepimentarium very narrow, composed of 3-5 rows of concentric dissepiments. Tabulae horizontal, slightly concave or flexuous in medial part and inclined toward periphery, with 5-6 of them occupying a space of 5mm. Remarks In the size of corallites, this species is similar to Fomichevella hoeli (Holtendahl) (Fedorowski, 1975), but in the latter, the septa are less numerous shorter and slightly thickened. Horizon and locality Same as the preceding species. Lytvophyllum flexuosum sp. nov. (Pl. III, figs. 4a, b) Description Corallum fasciculate. In early stage: corallites measuring 2.5-3.5mm in diameter; septa of one order, with 7-12 in number; cardinal and counter septa extending to center and connected together; peripheral cystose beginning to develop. ln late stage: corallites measuring 4.5-6mm in diameter; septa of two orders, (12-14)+(12-14) in number; major septa with a lengthe of about 1/2 the radius of corallites while minor ones about 1/3-1/2 as long as major ones; peripheral cystose larger and irregular, arranged in l row; median plate unstable; tabulae convex or horizontal. Remarks In the size of corallites and the number of septa, this species is similar to Lytvophyllum insolitum X. Y? (1980), but in the latter, the septa are straightened and shortened, the minor septa are less developed and the peripheial cystose discontinuous. Horizon and locality Upper Carboniterous Chuanshan Formation; Xiazhen, Yushan County. Nephelophyllum mixocolumellum sp. nov. (Pl. V, figs. 3a, b; text-fig 4) Description Corallum compound massive. Corallites irregularly polygonal, measuring 16 mm in diameter. Interwalls composed of loose scale-like lamellae or vanished. Peripheral cystosepimentarium wide, with a width of about 1/2 the diameter of corallites. Septal zone measuring 6.5mm in diameter, with septa (17-18) + (17-18) in number; major septa extending to the center but not connected with axial column; minor ones thinned, about 1/2-2/3 as long as major ones. Axial column measuring 1.2 × 1.8mm or 2×2.8mm in diameter, composed of a median plate, a few radial lamellae, and vesicule-like tabellae arranged in no more than 5 rows, sometimes with a septum extending to the center to form stereocolumella which measures 0.8×1.5mm in diameter, bearing a few spines. Tabulae complete and inclined toward the axis or incomplete and anastomosing, with 9-10 of them occupying a space of 3mm. Remarks In the number of septa, this species resembles Nephelophyllum hexagonum Wu et Zhao (1974), but in the former, the axial structure is heterogeneous. Horizon and locality Lower Permian Chihsia Formation; Xiaofang of Mengshan, Shanggao County. Carinthiaphyllum eostrotionideum sp. nov. (Pl. III, figs. 2a-d) Description Corallum loose, fasciculate. Corallites elliptical, measuring 6 × 5.5mm in diameter, with a few indistinct peripheral cystose. Septa of two orders, 19+19 in number, pinnate in arrangement, evenly thickened and slightly flexuous; major septa extending to the center; minor ones about 4/5 as long as major ones. Dissepimentarium composed of 1 row of concentrical or angular dissepiments. Stereocolumella irregular in shape; median line distinct. In the section of 7.5×5.5mm in diameter, except the slightly expanded stereocolumella, other features the same as the preceding section. In the section of 9.5×8.5mm in diameter, septa slightly thickened, minor ones slighly shortened, dissepiments mostly angular and counter septum connected with stereocolumella. In longitudinal section, dissepimentarium composed of l row of unequal-sized and discontinuous dissepiments. Tabulae horizontal to inclined toward periphery from early to later stages. Remarks Based on the tabulae inclined toward periphery, this specimen belongs to Eostrotion, but the specimen has pinnately arranged septa, with the occurrence ot a few peripheral cystose, and so belongs to Carinthiaphyllum. Horizon and locality Same as the preceding species. Monothecalis diplofermis sp. nov. (Pl. VI, figs. la, b) Description Corallum compound massive, with corallites of both Chushenophyllum and Polythecalis types. In Chushenophyllum-type corallites, distance between centers of two adiacent corallites about 7-10.5mm; interwalls vanished. Septa zones measuring about 3.5-4.5mm in diameter; septa of two orders, (15-16)+(15-16) in number, thinned and flexuous, with minor ones about 1/3-1/2 as long as major ones; cystosepimentarium wide, composed of medium-sized cystose without septal crests; syncolumella cobweb in shape, measuring about 1.2-1.5mm in diameter, composed of a median plate, a few radial lameilae and arched tabellae. In Polythecalis-type corallites, interwalls thickened; septal zones measuring 6.5mm in diameter; septa of two orders, (19-20)+(19-20) in number, thickened and elongate in wedge-shape; major septa extending to center and connected with axis; minor ones about 1/2 or 2/3 as long as major ones; cystosepimentarium narrow, composed of smaller cystose with septal crests; syncolumella composed of thickened median plate, 8 radial lamellae and 4-5 rows of tabellae. In longitudinal section, tabulae inclined toward axis, with 16-17 of them occupying a space of 5mm; septal crests forming lamellae arranged in cystosepimentarium. Remarks In both Chushenophyllum and Polythecalis types, this species is easily distinguished from other species of Monothecalis. Horizon and locality Lower Permian Chihsia Formation; Xiaofang of Mengshan, Shanggao County. Monothecalis rariepitheca sp. nov. (Pl. I, figs. 5a, b; text-figs. 3a, b) Description Corallum compound massive. Interwalls of corallites lessened. Cystosepimentarium well-developed, composed of cystosepiments mostly medium in size or with a few larger and irregular in shape. Septal crests absent. Septal zones circular or elliptical, measuring 3.5-5.5mm in diameter, composed of (14-16) + (14-16) septa in number; major septa almost extending to the axis; minor ones about 1/3-1/2 as long as major ones. Boundary between septa zone and cystosepimentarium distinct. Syncolumella nearly circular, thickened, measuring 1-2mm in diameter, composed of a shorter median plate, a few radial lamellae and semicircular or vesicule-like tabellae. Tabulae inclined toward the axis, sometimes flexuous. Remarks In the characters of septa and cystosepiments, this species is closely similar to Monothecalis nanjingensis Wu et Zhao (1983), but differs in its very incomplete interwalls, smaller septal zones and less numerous septa. Horizon and locality Same as the preceding species. Parawentzellophyllum lepingense sp. nov. (Pl. V, figs. la, b) Description Corallum compound massive, composed of irregalar polygonal corallites; distance between centers of two adjacent corallites about 7-12mm; interwalls thickened and somewhat vanished. Cystosepimentarium wide, with a width of about 1/2 the distance between centers of two adjacent corallites, composed of small and medium-sized cystose without septal crests. Septa of two orders, (17-19)+(17-19) in number, with outer part not extending to the cystose pimentarium; major septa extending to the center of corallites and almost in conjunction with axis, while minor ones slightly shorter than major ones. Syncolumetla circular or elliptical, measuring 1.5-2mm in diameter, composed of a flexuous median plate, discontinuous radial lamellae and smaller vesicule-like tabellae, closely arranged. Tabulae inclined toward the inner part and horizontal near axis. Remarks In the size of corallites, this species is similar to Parawentzellophyllum dantuense X. Y? (1980), but in the latter, the minor septa are less developed, the syncolumella is smaller and the interwalls are looser. Horizon and locality Upper Carboniferous Chuanshan Formation; Yongshan, Leping County. Pseudocarniaphyllum jiangxiense sp. nov. (Pl. III, figs. la, b) Description Solitary coral measuring 20mm in diameter, with regular peripheral cystose. Septa of two orders, 34+34 in number, with outer part discontinuously extending to the cystosepimentarium; major septa slightly thickened in tabularium, almost extending to center, but not connected with syncolumella; minor ones about 1/2 as long as major ones. Syncolumella cobweb-like, measuring 3.3×3mm, composed of a longer, flexuous median plate, a few radial lamellae and about 4-5 rows of complete tabellae bearing spines. Remarks This species resembles Pseudocarniaphyllum spiniforme X. Y? (1980), but in the latter, the syncolumella is smaller, the septa are less numerous and the cystosepimentarium is wider. Horizon and locality Upper Carboniferous Chuanshan Formation; Jingzishan, Pengze County. Eokepingophyllum acolumellum sp. nov. (Pl. IV, figs. 2a, b; text-figs. 5, 6) Description Corallum compound massive, composed of irregular corallites. Interwalls composed of smaller prickles. Distance between centers of two adjacent corallites about 10-12 mm. Septa of two orders, (17-19) +(17-19) in number, slightly thickened, with outer part extending to the cystosepimentarium; major septa longer and extending to the axis; minor ones slightly shorter than major ones. Peripheral cystosepimentarium narrow, composed of irregular cystose with discontinuous septa. Axial structure absent or sometimes composed of a septum extending to the center. Tabulae steeply inclined toward the axis. Remarks In the width of cystosepimentarium, this species is similar to Eokepingophyllum simplex X. Y? (1980), but in the latter, the axial structure is slightly developed and the minor septa are less developed. Horizon and locality Upper Carboniferous Chuanshan Formation; Yongshan, Leping County. Peiaphyllum anguiporum sp. nov. (Pl. V, figs. 2a, b; text-fig. 7) Description Corailum compound massive, composed of irregularly polygonal corallites. Interwalls thinned, partly vanished and median lines distinct. Mesopores triangular among corallites, with side 1.2-4.5mm in length. Distance between center of two adjacent corallites about 6-10mm. Peripheral cystosepimentarium developed, composed of smaller to medium-sized and irregular-shaped cystose. Septa of two orders, 28+28 in number, thinned and flexuous, sometimes with outer part discontinuously extending to cystosepimentarium; major septa extending to the axis and connected with syncolumella; minor ones about 1/3-1/2 as long as major ones, with some shortest. Syncolumella nearly cobweb-like, measuring 2-3mm in diameter, composed of thinned, flexuous and unstable median plate, discontinuous radial lamellae and 5-6 rows of tabellae. Tabularium composed of clinotabulae, with 3-5 of them occupying a space of 3mm, and smaller, horizontal or inclined tabulae, with 3-4 of them occupying a space of 3mm. Remarks This species resembles Peiraphyllum insolitum X. Y? (1980), but in the former, the mesopores are triangular. Horizon and locality Upper Carboniferous Chuanshan Formation; Yangjiaokeng, Chongyi County.