摘要
本文记述了采自四川省东南部武隆桐梓下志留统龙马溪组的两个三叶虫新种,Aulacopleura Wulongensis sp.nov.和Raphiophorus sichuanensis sp.nov.,并对Aulacopleura Hawle et Corda,1847属现有的四个亚属进行了讨论。
Two new trilobite sPecies, Aulacopleura wulongensis sp. nov. and Raphiophorus sichuanensis sp. nov. are described and illustrated from the upper part of the Early Silurian Longmaxi Formation of Tongzi, Wulong, southsastern Sichuan Province. Of the two genera, Aulacopleura Hawle et Corda and Raphiophorus Angelin, the representative of Aulacopleura is recorded for the first time from the Silurian strata of China. Three subgenera, twenty three species (including A. wulongensis sp. nov.) and five subspecies assigned to the genus are listed. A discussion of the subgeneric classifcation of the genus is given. In the present paper, the subgenus A. (Aulacopleurella)Alberti is regarded as a genus of the family Aulacopleuridae Angelin rather than a subgenus of the genus Aulacopleura because it differs from any other genus of the family in exhitbiting long, stem-like palpebral lobes and an anterior border with spines. The subgenus A. (Aulacopleuroides)was erected by Chu et Zhang(1979) with A(Aulacpleuroides)mirus Chu et Zhang as type species. According to the author's opinion, however, the type species is quite similar to A. (Aulacopleura) konincki haueri(Frech, 1887), A. (Aulacopleura)nitida(Barrande, 1846)and so forth in having a shorter glabella, shorter genal spines and palpebral lobes placed more forward. The chief differences between them are that the former bears smaller basal lobes of glabella and a more segmented pygidium. It is open to doubt to erect a new subgenus based on a little differentiation like this. Thomas, A. T. and Owens, R. M. S 1978) restudied the type species of the two subgenera A. (Aulacoplea) Hawle et Corda and A. (Paraaulacopleura)Chaubet and pointed out that the subgenus A.(Paraaulacopleura)is a subjective junior synonym of the subgenusA. (Aulacopleura). The new species A. wulongensis sp.nov, like some previously described species(for instance, A. (Aulacopleura)bohemica pribyl)shows some characters between the two subgenera (see the late part for further details). Moreover, some specimens assinged to A. (Aulacopleura) konincki (Barrande, 1846) (precisely speaking, A. (Aulacopleura) konincki konincki), the type species of the subgenus A. (Aulacopleura), seem to be somewhat flattend, thus having a shorter glabella and a longer(sag.)preglabellar field and being different from the subgenus A.(Paraaulacopleura)(Prantl, F. et Pribyl, A. 1950, pl. Ⅲ, fig. 7; Levi-Setti, R. , 1975, p1. 124 and Thomas, A. F. et Owens, R. M., 1978, p1. 7, flg. 10). These facts further prove that there are no features by which the subgenus A. (paraaulacopleura) can be separated at subgeneric level from the subgenus A. (Aulacopleura). A list of species assigned to the genus Raphiophorus Angelin is also presented. It contains twenty one species, including R. sichuanensis sp. nov. described herein. The simplified descriptions of the two new forms are shown as follows.
