中国科学院南京地质古生物研究所机构知识库

记述了产于广东三水盆地华涌组的金龙鱼化石新材料,定为骨舌鱼科金龙鱼属一新种:三水金龙鱼(Scleropages sanshuiensis sp.nov.)。新种在头部骨骼、尾骨骼、各鳍形状和位置以及具有网状鳞片等方面与中华金龙鱼(S.sinensis)和现生金龙鱼(Scleropages)极为相似,因而归入该属。在金龙鱼属的4个现生种和中华金龙鱼之中,三水金龙鱼和中华金龙鱼更为接近。但是,三水金龙鱼在下列特征上明显不同于中华金龙鱼:鼻骨上有纹饰,第三眶下骨略小于第四眶下骨,鳃盖骨后腹缘的内凹浅,胸鳍往后延伸到腹鳍起点,躯椎上的神经棘不愈合,椎体横突长。三水金龙鱼与现生的金龙鱼也有相似之处,如鼻骨有纹饰、椎体横突长。同样,中华金龙鱼也有与现生金龙鱼相似的地方,如第三眶下骨略大于第四眶下骨、大多数躯椎上的神经棘愈合。尚不清楚三水金龙鱼和中华金龙鱼中哪一个与现生种更接近,这两个化石种可能处于相同的进化水平。中生代骨舌鱼类主要发现于中国,始新世骨舌鱼类化石在中国的发现也在逐渐增多,金龙鱼属(Scleropages)和骨舌鱼属(Osteoglossum)的共同祖先在始新世以前可能生存于东亚,并随后扩散到澳洲和世界其他地方。华涌组的骨舌鱼类和湖北松滋洋溪组的可以直接比较,因此,本项研究支持华涌组的时代为早始新世的观点。

A new species of Scleropages,an extant genus of the Osteoglossidae,is described from the Lower Eocene Huayong Formation in the Sanshui Basin,Guangdong,China.The new species,Scleropages sanshuiensis sp.nov.,was attributed to Scleropages because it possesses the diagnostic features of the genus in skull bones,caudal skeleton,the shape and position of fins,and reticulate scales.Compared with the four extant and one fossil species of Scleropages,the new species is most similar to the fossil one,S.sinensis.However,S.sanshuiensis is different from S.sinensis in many aspects:the nasal is ornamented;the third infraorbital is slightly smaller than the fourth;the posteroventral margin of the opercle is slightly concave;the pectoral fin extends just to the beginning of the pelvic fin;the distal ends of the neural arches on abdominal centra are not fused;the parapophyses are much longer than in S.sinensis.Scleropages sanshuiensis is closer to S.sinensis but it shares two characters with the living species(ornamented nasal and long parapophyses)while S.sinensis shares two characters with the extant ones too(the third infraorbital slightly larger than the fourth and the distal ends of the neural arches on most abdominal centra fused).It is not clear which one of the two fossil fishes is more closely related to the living fishes.The two fossils are probably in the same evolutionary level.In addition to the rich Mesozoic osteoglossomorphs,many Eocene ones were also found from China.The common ancestor of Scleropages and Osteoglossum may live before the Eocene in East Asia and then dispersed to Australia and other places of the World.Huayong Formation and Yangxi Formation,Songzi,Hubei are comparable and possibly deposited contemporaneously.Therefore,this work supports the view that the Huayong Formation is of Early Eocene.