摘要
一、前言在石炭、二叠纪地层中含有一类由多角柱状或圆柱状个体所组成的块状或丛状复体珊瑚,它们具有郎士德型鳞板带和轴部构造,过去人们常将它们鉴定为Lithostrotionella Yabe et Hayasaka,1915。实际上,这类珊瑚包括Stelechophyllum,Aulostylus,Acrocyathus,Petalaxis,Huanglongophyllum,Thysanophyllum,Actinocyathus,Lonsdaleia,Kleopatrina(Porfirievella)。在广西南丹晚石炭世早期Profusulinella带下部地层中盛产lithostrotionelloid珊瑚,经鉴定共有5属24种(及亚种),它们是Acrocya-
The Lithostrotionelloid colonial oorals were put forward representing Stelechophyllum, Aulostylus, Acrocyathus, Patalaxis, Huanglongophyllum, Thysanophyllum, Actinocyathus, Lonsdaleia and Kleopatrina (Porfirievella), which had very similar internal features in corallites and flourished in the Carboniferous, mainly based on Sando's studies (Sando, 1982; 1983). Their coloniality has been discussed, with the conclusion that the fasciculate corals basically acted on lateral increase and the cerioid on peripheral increase, and that although both of the polyps were similar to solitary corals and with no common tissue between each other in adults, the latter was obviously superior in connection between corallites, intensity of skeleton structure, utilization of all the available space and re- duction in the surface area of the exposed skeleton. Also discussed are their axial features, by which most of the lithostrotionelloid genera are distinguished, such as the developed or undeveloped axial tabellae, the exial aulo, septal lamellae or radial carinae, the concentric trace of tabulae, the continuous or discontinuous axial structure, etc. The lithostrotionelloid corals described in the present paper were collected from the Lower Profusulinella zone in Nandan, northern Guangxi, containing 24 species and subspecies (including 7 new species and subspecies) within 5 genera, namely, Acrocyathus: A. pennsylvanicus. (Shimer), A. hsujiulingi (Yoh); A. tingi (Chi); A. tingi proliferus subsp, nov.; A. grechovkae (Degtjarev);A. yohi sp. nov. Actinocycathus: A. lutugini (Fomichev); A. densiconus (de Groot) Lonsdaleia: L. cf. chutsingensis (Chi); L. huangi Chi Petalaxis: P. nandanensis sp. nov.; P. simplex (Hayasaka); P. monoayclicus (de Groot); P. monocyclicus (de Groot); P. rosicum Zheng; P. confertus Kozyreva; P. sexangulus (de Groot); P. major (de Groot): P. grootae breviseptatus subsp. nov.; P. sinensis sp. nov. Huanglongophyllum: H. longhuoense (X. Yu); H. elegantum sp. nov.; H. cf. parasimplex X. Yu; H. distans sp. nov.; H. minor (Wu et Zhao). Description of new species and new subspecies Acrocyathus tingi proliferus subsp, nov. (P1. Ⅰ, fig. 2; p1. Ⅱ, fig. 4) Corallite with strongly-thickened walls. 5—7mm in diameter. Major repta long, 15—18 in number; minor septa about 1/2 or more as long as major ones. Inner wall developed along outer margin of tabularium. Columella composed of a thickened plate connected with the counter septum, usually augmented by a few septal lamellae or radial carinae and 1—2 cycles of concentric trace of tabulae. Dissepimentarium composed of 1 row of inflated dissepiments in various sizes. Tabulae commonly complete and deflected upward at columella, with 14—15 of them in 5 ram. Ratio of tabularium width to corallite diameter 0.62—0.69. Peripheral increase. This new subspecies is distinguished from A. tingi (Chi) by its strongly-thickened corallite walls, thicker septa and columella, developed inner wall and more tabulae in 5mm. Acrocyathus yohi sp. nov. (P1. Ⅱ, fig. 1) Corallite 3—4mm in diameter. Major septa long, 18—20 in number; minor ones in short spines. Columella composed of a thickened plate, usually augmented by very few radial carinae or septal lamellae and 1 cycle of concentric trace of tabulae. Dissepimentarium poorly lonsdaleoid, with 1 row of dissepiments. Tabulae complete and conical, deflected upward at: columella, with 8—11 of them in 5mm. Ratio of tabularium width to corallite diameter 0.7—0.82. Peripheral increase. This new species is similar to A. hsujiulingi (Yoh), but differs in the smaller corallite diameter, commonly differentiated axial structure and poorly lonsdaleoid dissepimentarium. Petalaxis nandanensis sp. nov. (P1. Ⅱ, fig. 3; p1. Ⅲ, fig. 1) Corallite 3—6mm in diameter. Major septa about 1/2 as long as the radius of tabularium, 12—16 in number; minor ones in short spines. Columella composed of a simple plate connected with the counter septum and augmented by a few radial carinae. Tabulae complete, usually horizon tal, with 8—11 in 5mm. Dissepimentarium composed of 1, rarely 2 rows of large lonsdaleoid dissepiments. Ratio of tabularium width to corallite diameter 0.57—0.67. Peripheral increase. This new species is similar to P. sexangulus (de Groot), but differs in the complete and usually horizontal tabulae, and the columella commonly with radial carinae. Petalaxis grootae breviseptatus Subsp. nov. (P1. Ⅴ, fig. 7) Corallite 4—6 mm in diameter. Major septa very short, 14—16 in number; minor ones in short spines. Columella composed of a dilated plate with radial carinae, connected with the counter septum. Dissepimentarium composed of 1, rarely 2 rows of inflated dissepiments in varying sizes Tabulae complete, and rarely incomplete, horizontal, regularly with 8—12 in 5 ram. Ratio of tabularium width to corallite diameter 0.67—0.70. Peripheral increase. This new subspecies is distinguished from P. minor (de Groot) by the smaller corallite diameter, the number of septa which are much shorter, and the narrower dissepimentarium. Petalaxis sinensis sp. nov. (Pl. Ⅳ, figs. 11, 12; texi-fig. 15) Corallite 4—9 mm in diameter. Major septa approaching but seldom reaching the columella, and mostly extending into the dissepimentarium, 18—22 in number; minor onespoorly developed. Columella composed of a thickened plate connected with the counter septum and augmented by 1—6 septal lamellae or radial carinae. Tabulae usually complete, sharply deflected downward at columella, with 3—5 in 5mm. Dissepimentarium composed of 1, seldom 2 rows of dissepiments in varying sizes. Ratio of tabularium width to coraltire diameter 0.6—0.8. Peripheral increase. Huanglongophyllum elegantum sp. nov. (p1. Ⅴ, fig. 4) Corallites closely arranged, with a diameter of 5—9 mm. Major septa thin and long, approching the columella, 17—25 in number; minor ones poorly developed. Columella composed of a thin plate connected with the counter septum. Dissepiraentarium poorly lonsdaleoid, composed of 2, seldom 4 rows of dissepiments in varying sizes. Tabulae complete or incomplete, concave, with 5—6 in 5 mm; clinotabulae developed on margins. Ratio of tabularium width to corallite diameter 0.65 Huanglongophyllum dlstans sp. nov. (P1. Ⅴ, figs. 1, .3) Corallites sparsely arranged, with a diameter of 8—10 mm. Major septa long, 15—25 in number; minor ones short. Columella composed of a thick plate connected with the counter septum. Dissepimentarium poorly lonsdaleoid, composed of 1 row of dissepiments or 3—4 rows in part of it. Tabulae complete or incomplete, concave, with 4—7 in 5 mm; clinotabulae developed on margins. Ratio of tabularium width to corallite diameter about 0.55. Lateral increase. H. longhuoense (X. Yu) and H. elegantunt sp. nov. are similar to this new species in internal features of corallites, but H. longhuoense has a large colony with closely arranged corallites, a stronger skeleton and a differentiated columella; H. elegantum has a large colony with closely arranged corallites and a thicker skeleton; while the new species has a small colony with corallites which are usually conical, with deep contractions on wall and Tryplasma, arranged sparsely, and a stronger skeleton. Thisi shows that the 3 species were originated from the same type and later differentiated from each other because of their different living positions.
出处
《古生物学报》
CAS
CSCD
北大核心
1989年第4期522-545,576-580,共24页
Acta Palaeontologica Sinica
