The chondrichthyan fauna from the Middle-Late Triassic of Guanling (Guizhou province,SW China)

The Recent volutids Cymbiola and Melo burrow in a forward direction. This agrees well with the spiral terrace pattern observed in Eocene Volutidae, thus strengthening the idea that they were forward burrowers as well. The presence of collabral terraces near the aperture in the Cassidae suggests an oblique burrowing direction, by convergence with the Nassariidae. This is confirmed by observations on living cassids. The sutural canals and associated structures of the Olividae and Seraphidae are functional in detecting whether the posterior region of the shell is buried. This confirms the idea that fossil Strombidae possessing similar features were burrowers.

In contrast with these “predictable”; observations, burrowing was observed in a few gastropods the shell morphology of which would seem to exclude such behaviour, such as Architectonica, Cymatium, Volema and Bolinus. Thus, a few morphologic criteria appear to be reliable and of general applicability in inferring burrowing habits in gastropods. At the same time, the broad variety of burrowing mechanisms and life habits of gastropods makes it unlikely that general criteria will ever be found to exclude burrowing habits on the basis of shell morphology.     

记贵州关岭生物群中的大型鱼龙Shastasaurus(英文)

贵州关岭三叠纪法郎组瓦窑段除产出大量保存完整的海百合化石外,还产出多门类海生爬行动物化石。迄今为止,关岭生物群已报道的中-大型鱼龙类有6属6种,包括邓氏贵州鱼龙(Guizhouichthyosaurus tangae)、蔡胡氏典型鱼龙(Typicusichthyosaurus tsaihuae)、梁氏关岭鱼龙(Guanlingsaurus liangae)、亚洲杯椎鱼龙(Cymbospondylus asiaticus)、美丽盘江龙(Panjiangsaurus epicharis)和卧龙岗卡洛维龙(Callawayia wolonggangense)。一些种属的存在长期以来争议较大,目前多数观点倾向将Cymbospondylus asiaticus和Panjiangsaurus epicharis归并于Guizhouichthyosaurus tangae,将Typicusichthyosaurus tsaihuae归并于Guanlingsaurus liangae。Guanlingsaurus以具有较短的吻部和较多的荐前椎数目而与Guizhouichthyosaurus有明显的不同(Maisch et al.,2006)。虽然Maisch et al.(2006)对G.tangae进行了重新研究,但他们的研究重点是头部骨骼,有限的头后骨骼信息来自一具未经充分修理的骨架(GNP-d41),一些特征未能清晰揭示。头后骨骼材料的缺乏限制了对该种分类位置的判断(Maisch et al., 2006)。在中、晚三叠世大型鱼龙中,肩带和腰带骨骼的形态、前肢和后肢骨骼的特征常具有非常重要的系统分类学意义。本文通过对关岭生物群的一具保存完整的大型鱼龙骨骼化石的详细研究,对Guizhouichthyosaurus tangae的归属进行了重新修订。研究标本(IVPP V 11853)产于贵州省关岭县新铺乡法郎组瓦窑段。修理后的骨架全长5.2 m,以腹面向上保存,尾部后部以右侧面向上保存。除前、后肢部分残缺外,其他部位均保存完整,肩带骨骼和腰带骨骼均原位保存。头骨背腹向压扁,仅右侧角的上颞骨有部分破损。新材料的头后骨骼特征表明该种应该属于萨斯特鱼龙科(Shastasauridae)的萨斯特鱼龙属(Shastasaurus)。Shastasaurus是一个广为人知的晚三叠世大型鱼龙化石属,最初建立于美国加利福尼亚州的Shasta地区,包括5个种(Merriam,1895,1902,1908)。由于建立这些种的化石材料均保存不好,尤其是模式种仅建立于几块背椎、背肋和两块耻骨之上,导致有关萨斯特鱼龙属和萨斯特鱼龙科的一些特征定义不明确。后人倾向于将已建立的种进行归并,即将Shastasaurus alexandrae、S.altispinus和S.osmonti划归模式种S.pacificus,将S.careyi另归入Shonisaurus sp.。虽然萨斯特鱼龙类的其他属,如Shonisaurus、Besanosaurus、Metashastasaurus、Pessosaurus等,在加拿大、墨西哥、意大利、瑞士等地的中、晚三叠世地层中被陆续发现和报道,但除美国加利福尼亚州的材料外,其他地区发现的萨斯特鱼龙属的化石均未得到广泛认可。本文将G.tangae归入萨斯特鱼龙属主要依据对该种模式标本(Gmr 009)的重新观察和对该种一新材料(IVPP V 11853)头后骨骼的深入研究。两骨架的头后部分尤其是前肢和肩带均表现出与已知的萨斯特鱼龙属各种的极大相似性,具体包括:椎体稍短;颈肋近端双头;尾椎腹侧Y型人字骨发育;锁骨细长,中部向后弯;乌喙骨斧状,中部收缩形成前后缘不对称的"茎";肩胛骨呈宽的镰刀状,前缘强烈外展;肱骨、桡骨、尺骨均较短;肱骨和桡骨前缘具凹缺;桡骨明显大于尺骨,桡骨后缘和尺骨前缘略凹入;相对较大的桡腕骨等。腰带和后肢特征与萨斯特鱼龙类其他属差别不大。除头后骨骼特征外,关岭材料的头骨特征也与萨斯特鱼龙属惟一的一个保存有部分头骨骨骼的S.alexandrae的特征大体相符,如具有大的、前后略拉长的眼眶,相对较窄的颊部,横向伸展的鼻骨和额骨的接触面,颞孔稍小于眼眶等。同时,通过与萨斯特鱼龙类其他各属化石的对比研究发现,虽然一些研究者认为萨斯特鱼龙属的荐前椎数目在55个左右,且指(趾)骨为3指(趾),但鉴于已经发现同属于萨斯特鱼龙类的Shonisaurus、Besanosaurus、Metashastasaurus等属或者具有超过60的荐前椎数,或者指(趾)骨为4指(趾),同时迄今为止尚无完整的萨斯特鱼龙属的化石标本被发现,有关其荐前椎数目和指(趾)骨列数仅是推测,因此基于中国贵州关岭的标本,本文认为萨斯特鱼龙属很可能具有超过60的荐前椎数,同时指骨(趾骨)是4指(趾)。在观察和对比了众多产于关岭的大型鱼龙骨骼化石的基础上,将邓氏贵州鱼龙、亚洲杯椎鱼龙和美丽盘江龙重新厘定为邓氏萨斯特鱼龙,并对该种的头后骨骼特征进行了详细描述。这是萨斯特鱼龙属的分子第一次在中国被确认,为了解该属鉴定特征和古地理分布提供了新的信息。     

贵州关岭晚三叠世法郎组瓦窑段鱼类化石初步观察

描述了关岭新铺地区晚三叠世法郎组瓦窑段中发现的鱼类5目5科5属5种和1未定种,其中1新属5新种,它们是Guizhoucoelacanthus guanlingensis Liu,Yin et Wang S Y gen.etsp.nov.,Birgeria guizhouensisLiu,Yin et Luo sp.nov.,Birgeriasp.,Pholidopleurus xiao waensis Liuet Yin sp.nov.,Peltopleurus brachycephalus Liu et Yin sp.nov.,Guizhoueugnathus largusLiu,Yinet Luo sp.nov.。关岭法郎组瓦窑段鱼类组合与邻区兴义晚三叠世法郎组竹杆坡段(卡尼早期)鱼类组合明显不同,瓦窑段的层位在竹杆坡段之上,其时代可能为卡尼中期。     

Treasure with blood: On the discovery of Traumatocrinus (Echinodermata,Triassic) crowns in China

A team of three paleontologists led by the important Triassic worker Te-You Hsu were killed in Guizhou during a field mapping project in 1944. A.T. Mu studied Hsu's crinoid collection and named a new species Traumatocrinus hsui after him in 1949. The first edition of crinoid Treatise did not acknowledge Mu's work and placed Traumatocrinus as junior synonym of Encrinus. However, it is now regarded as a valid taxon in the new edition published in 2011. During this study, original specimens reported by Mu were re-examined. Among them, 21 specimens survived to this day, and the rest of specimens mentioned in Mu were lost during the Second World War. The collection is illustrated with modern standards for the first time. Despite the hard working conditions endured by the Chinese workers during and shortly after the Second World War, this collection, including eleven slabs of crowns, one cup, eight columnals, and one holdfast curated in Nanjing, is the basis for family Traumatocrinidae.     

飘泊海百合类在我国三叠系的首次发现及其意义

产于贵州关岭三叠系营浮游生活的漂泊海百合类(roveacrinids)是该类化石在我国的首次发现,描述其中2种:Osteocrinus cf.virgatus和Osteocrinus spinosus。Osteocrinus的形态是以萼部为中心、由位于中背骨之上的5块辐板生长出5个一级腕,从5个一级腕的第2个腕骨后再分出10个二级腕,共同构成一个纤巧的辐射对称的身体结构。鉴于辐板外侧中上部的韧带凹口与冠部中轴近于平行,腕与冠部的中轴近于垂直联结,表明Osteoc-rinus的形态与Saccocoma tenella(Goldfuss)雷同,其生活方式应与之类似,为口面向上的浮游生活方式。     

贵州关岭地区中晚三叠世法郎组中的软骨鱼类微体化石新材料

软骨鱼类的微体化石具有区域甚至全示性的地层对比潜力,还可以用于有机成熟度的分析。贵州关岭中晚三叠世法郎组产数量丰富,类型繁多的软骨鱼类微体化石,本文按照形态分类系统,对其进行了分类和描述。     

贵州关岭晚三叠世一大型鱼龙类头骨

记述了产自贵州关岭上三叠统杯椎鱼龙属一新种——亚洲杯椎鱼龙(Cymbospondylusasiaticus sp. nov)。标本为两件几乎完整的头骨,产于法朗组瓦窑段的泥质灰岩中,这是目前已知惟一的晚三叠世(Cymbospondylus属的标本,也是该属时代最晚的一个种。亚洲杯椎鱼龙头部最明显的特征是下颌牙齿仅分布于齿骨的前半部分。此外,新种的吻部极长,超过头骨全长之半,上颌骨非常发达,并且具有已知鱼龙类中最小的眼眶。亚洲杯椎鱼龙是这一大型鱼龙类在北美和欧洲以外地区的首次记录。     

贵州关岭新铺晚三叠世早期(Carnian)康尼克贝类腕足动物一新属--Pseudokoninckina

Pseudokoninckinagen.nov.归于康尼克贝类。模式种Pseudokoninckina xinpuensisgen.etsp.nov.的模式标本采自贵州关岭县城西南约35km新铺乡喇嘛村上三叠统下部(Carnian)竹杆坡组中部黑灰或黄灰色石灰岩。其贝体强烈膝曲,拖曳部长;背壳极为深凹,侧坡高又陡峭,两侧区和拖曳部呈薄壳状;两耳翼端强烈向背方膝曲;背三角孔覆有背三角双板,但腹三角孔洞开。腹内两侧隔板极高又长;腹中隔脊低宽,前部二分叉,后部三分叉。背内第三壳层厚,在背壳底两侧区隆起呈两条隆脊;主突起高强。壳表饰有微弱同心线和毛发状放射纹。这些特征在康尼克贝类中是很独特的。     

关岭新铺卡尼期腕足类古生态及对创孔海百合假浮游生活方式的质疑

关岭新铺晚三叠世早期卡尼期(Carnian)龙层及其下伏竹杆坡组上、中部的腕足类从上到下可划分为Linguloid,Laballa,Pseudokoninckina等3个化石群落。根据各群落特征分子的固着方式、生活习性、贝体形态和大小,以及与其他生物共同埋藏情况,并考虑围岩性质等方面的综合因素,得出Pseudokoninckina群落的古生态底域位于BA4内侧至BA3外侧,Laballa群落的古生态位置相当于BA2,而Linguloid群落则为BA1。在此基础上进一步阐明关岭新铺从竹杆坡组中部至龙层呈现明显海退过程,其古生态底域位置从BA4内侧至BA3外侧一直退到BA1。依据此变化绘出新铺卡尼期海平面下降示意图。对创孔海百合被一些学者推断为假浮游的生活方式提出质疑和讨论,得出当时创孔海百合不可能为假浮游的生活方式,它们应是营底栖的。     

THE LATE TRIASSIC BLACK SHALES OF THE GUANLING AREA, GUIZHOU PROVINCE, SOUTH-WEST CHINA: A UNIQUE MARINE REPTILE AND PELAGIC CRINOID FOSSIL LAGERSTÄTTE

Abstract:  Black shales of the lower member of the Carnian Xiaowa Formation (previously known as the Wayao Member of the Falang Formation or as the Wayao Formation) in the Guanling area, Guizhou Province, south-west China, are yielding a rich marine reptile fauna and exceptional remains of pelagic crinoids. The black shales represent deposition on the drowned southern margin of the Yangtze Platform during a Maximum Flooding Interval. The relatively reduced sedimentation rates led to the formation of the Lagerstätte through the accumulation of fossils in the anoxic bottom sediments over a prolonged period of time. Invertebrate fossils represent almost exclusively pelagic forms, such as a diverse ammonite fauna and halobiid bivalves. The spectacular finds of colonies of large (stem lengths > 11 m) crinoids of the genus Traumatocrinus attached to driftwood prove that this crinoid was the first to evolve a pseudoplanktonic life style. The other crinoid is the planktonic roveacrinid Osteocrinus . The marine reptile fauna, represented by probably hundreds of skeletons, is numerically dominated by three species of ichthyosaurs and four species of thalattosaurs. The thalattosaurs fill a palaeobiogeographic gap between the Alpine thalattosaur faunas and those from western North America. Two species of placodonts are rare finds. As for the thalattosaurs, the placodont occurrences greatly expand the geographic range of the group because placodonts have been known previously only from the Mediterranean region, the Alps and the Muschelkalk Basin. The unique abundance of thalattosaurs contrasts with a scarcity of fishes. Although we suggest that the fauna is authochthonous and inhabited surface waters, it must have represented an unusual ecosystem. However, the possibility remains that both the marine reptiles and the Traumatocrinus colonies were concentrated in the region by currents and do not reflect the biocoenosis.