串管海绵一新属——新瓜达卢佩海绵属(Neoguadalupia),兼论塞巴加斯海绵科各属间的关系

本文论述了云南广南董那孟下二叠统生物礁内的串管海绵化石,提出塞巴加斯海绵科具有三个明显演化分枝,这是它们对不同生态环境长期适应的结果。文章讨论了新属Neoguadalupia与相关属的区别,确立了在串管海绵演化史上的地位,并详细描述和讨论了Neoguadalupia elegana gen.et sp.nov.

A NEW GENUS NEOGUADALUPIA WITH NOTES ON CONNECTIONS OF INTERRELATED GENURA IN SEBARGASIIDAE, SPHINCTOZOA

In Guangnan county of southeast Yunnan, some typical reefs are known from Maokou Formation, Lower Permian. Dongnameng reef is one of these and contains abundant well-preserved framebuilders, including sphinctozoans, inozoans, tabulozoans, hydrozoans and calcareous algae. A new genus, Neoguadalupia, which belongs to Sebargasiidae of Sphinctozoa, is established and compared.The Sebargasiidae freguently occurred in Permian buildups of South China. At present, 11 genura are involved in the family and found separately from Hubei, Sichuan, Guizhou, Guangxi and Yunnan Provinces. Three branches can be differentiated within the group and each one of these is correlated with special sediment types:cylindrical forms like Amblysipho-nella, Lichuanospongia, Cystauleies and Polycystocoelia lived on higher energy environments, and tabular forms (Neoguadalupia, Polyphymaspongia and Subascosymplegma) are common in the lower energy area, whereas moniform shapes such as Waagenella, Colospongia and Girtycoelia are found in higher energy regions, and have also been found growing on some lower energy parts of reef complexes. It is noteworthy that the number of chambers is gradually increasing from Amblysiphonella, Lichuanospongia, Cystauletes to Polycystocoelia. This phenomenon can be interpreted as an adaption of varying levels of water energy. The most obvious relations appear to have existed between sedimentary enviroments and growth forms of the Sebargasiidae. The new genus and its a new species are described briefly as follows:Neoguadalupia gen. nov.Diagnosis: Flat and tabular bodies with numerous chambers which generally are spherical or subspheroidal and one superposed above the other. All of wall of the chambers are penetrated by numerous small pores. No filling structure occur in chambers. Central cavity is absent.Discussion: Neoguadalupia differs from Polyphymaspongia in having numerous pores on the wall of chambers and absenting filling tissue in the interior of body, The new genus shows a single layer in arrangement of chambers, whereas Polyphymaspongia appears to have two layer in it. The new genus resembles Subascosymplegma in the tabular from, but the latter has vesicular tissues in the segmental chamber with barrel vault-form.Type species: Neoguadalupia elegana gen. et sp. nov.Range and distribution: Permian, South ChinaNeoguadalupia elegana gen. et sp. nov.Diagnosis: Flat and tabular bodies with a number of pores (0.1-0.2 mm in diameter )on the wall. Chambers are frequently spherical or subspheroidal and are superposed one above the other. They are generally 3.5-5.5 mm high and 1.5-3.0 mm in diameter. The thickness of the whole tabular body is 1.5-3.0 mm, the length is 65 mm and the width is 25 mm. Arrangement of the chambers shows an overlap of scales in transverse section. The roof of the chambers are arched and is like a crescent shape in this section, and 1.2-2.2 mm high, 1.8-3.0 mm in width. No filling structure in the interior of chambers.