甘肃窑街、陕西安塞弓鲛类化石新材料

甘肃窑街红沟中侏罗统中产有锤纹弓鲛(新种)Hybodus clavus(sp.nov.)双粗纹无尖齿鱼(新种)Acrodus bicrasseplicatus(sp.nov.)在陕西安塞岔路坪中侏罗统中还采得一枚安定弓鲛 Hybodus antingensis Liu。一般认为弓鲛是河口相甚至海相鱼化石,从它在陕西北部的分布结合其它有关海相化石资料来看,在陕北中生代三叠纪确曾有海水分布,此海水可能持续到侏罗纪。

NEW MATERIALS OF HYBODONTIDAE IN GANSU AND SHAANXI

Some specimens of Hybodontidae were collected from Yaojie,Gansu provinceand Ansai,Shanxi province.They are:in Gansu:Hybodus clavus(sp.nov.)H.sp.Acrodus biscrasseplicatus(sp.nov.)in Shanxi:H.antingensis Liu,1962The new speces Acrodus biscrasseplicatus,is reprensented by several small detachedteeth,which do not exceed 5 mm.in length and are elongated-ovoid in shape.Thisspecies exhibits a prominent top longitudinal median wrinkle,the lateral wrinkles ofcrown,except four stout in median place,are few,faint and very short,reachedneither 0 the top nor 0 the root of the tooth.The four median ones united into two,and the two re-united into one under the top longitudinal median wrinkle.H.clavus is a new species too,the median principle cone is relatively high andsharp,its median vertical wrinkle stout and expanded as a drum-stick at the basal part,and the laterale wrinkles are comparatively weak.Hybodus was generally found in estuarine deposits in the localities out of China.In China,however,it was so far collected from Triassic and Triassic lacustrine sedi-ments of Twelve localities.The Early Triassic marine invertebrates(Brackiopoda,Echinodermata etc.)in Linyou,Chiskan and Tungchuan county and Late Triassic(orLower-middle Triassic)marine fish(Saurichthys)in Henshan county give some indica-tions that these lakes were probably connected with the sea.