滇西早泥盆世大瓣鱼科(Macropetalichthyidae)化石的发现

<正> 泥盆纪的大瓣鱼化石目前除在南美和非洲尚未发现外,在全球其他各洲分布甚为广泛.它的分布时代可由早泥盆世延续到晚泥盆世.据统计目前发现的该科化石已达12个属.我国目前发现的大瓣鱼科化石共有5个属种,分布于华南的下、中泥盆统,主要发现于下泥盆统.     

藏北申扎早泥盆世四射珊瑚群的发现及其地质意义

历年来的青藏高原的科学考察报告中,关于早泥盆世生物群的报道,只限于藏南珠穆朗玛峰地区发现的凉泉组生物群,包括笔石、竹节石等浮游型生物群,时代相当于早泥盆世布拉格期.(穆恩之等,1975;穆西南,1975).1980年夏,由中国科学院南京地质古生物研究所组织的考察队再次入藏进行地层古生物工作.在西藏地质局综合普查大队工作的基础上,于西藏北部申扎附近出露的海相泥盆纪地层中采获珊瑚化石和其它底栖门类化石.这个     

泰国-老挝黎府构造带晚泥盆世-早石炭世放射虫动物群及其地质意义

本文对老挝西北部和泰国东北部黎府构造带6个层状硅质岩考察点进行了放射虫化石调查研究,其中有5个点发现可供鉴定的放射虫化石,共鉴定放射虫化石9属23种,包括典型的晚泥盆世放射虫化石Helenifore robustum和早石炭世放射虫化石Albaillella cartalla,Al.undula,Al.paradoxa等,5个层状硅质岩考察点地质时代类似,为晚泥盆世至早石炭世。该调查成果表明,黎府构造带从泰国东北部延续到了老挝西北部万荣地区,其深海盆地演化历史应该在早石炭世晚期结束。     

新疆哈密地区晚泥盆世疑源类化石的发现及地质意义

从新疆哈密地区石城子北剖面7件样品获得分异度较高、有机质壁显著炭化保存的疑源类化石,根据其形态特征,共鉴定出14个形态属和15个形态种(其中8个未定种,3个比较种)。结合国内外古生代晚泥盆世已知疑源类组合进行比较,清楚表明当前获得的疑源类组合代表了晚泥盆世海洋微体浮游植物群面貌。我国涉及晚古生代疑源类生物地层的调查研究相对薄弱,而有关晚泥盆世疑源类化石的发现和报道更为匮乏,当前疑源类化石的发现,填补和丰富了新疆乃至国内晚泥盆世疑源类化石研究资料。该发现佐证了关于卡拉麦里洋在早石炭世闭合的认识;作为基础食物链的海洋微体浮游植物是重要成烃生物,晚泥盆世疑源类的保存预示研究区域具有石油、天然气勘察的前景。     

命名建议——以Duyunolepis代替Duyunaspis P'an et Wang,1978

<正> 最近我们在查阅文献的过程中发现早泥盆世无颌类化石都匀鱼Duyunaspis P'an et Wang,1978(见华南泥盆系会议论文集,300—307页,1978,地质出版社)是三叶虫都匀盾壳虫Duyunaspis Zhang et     

海南岛晚泥盆世—早石炭世牙形刺

作者描述了海南岛昌江县石碌地区昌江组首次发现的牙形刺Palmatolepis gracilis gracilis Bransonet Me-hl,P.gracilis sigmoidalis Ziegler,Polygnathus ansatus Ziegleret Klapper,Polynodosus germanus(UlrichetBassler),Neopolygnathus dentatus(Druce)等和白沙县金波地区南好组第二段的Siphonodella levis(Ni),Polygnathus cf. inornatus Branson等,共8属20种,并据此将含化石地层分别确定为晚泥盆世法门期和早石炭世杜内期早期。指出以往认为是中泥盆统吉维特阶带化石Polygnathus ansatus Ziegleret Klapper与法门期牙形刺化石共同出现于昌江组并非构造混杂所致,但并不排除可能是化石再沉积作用的原因。同意将Polynodosus属从Polygnathus属中分离出来,在我国首次采用Polynodosus。     

广西荔浦早泥盆世腹足类

腹足类化石采自广西荔浦栗木早泥盆世四排组,共3属4种:Oriostoma?lipuense sp. nov., Naticopsis sp., Murchisonia angulata Philips, Murehisonia bachelieri Rouault其中Murchisonia属的两种是西欧早泥盆世常见的分子。Oriostoma?lipuense是1个归属有疑问的新种。与腹足类共生的有早泥盆世的腕足类、轮藻和介形类等化石。     

新疆中天山汗吉尕组Helenifore robustum放射虫动物群及其年代地层学意义

汗吉尕组是新疆中天山温泉小区中泥盆统的一个地层单元,为海相碎屑岩夹火山碎屑岩沉积。过去在灰岩团块和灰岩砾石中发现较为丰富的中泥盆世珊瑚和腕足类化石。这次,我们在该组上部地层硅质岩透镜体中首次发现晚泥盆世弗拉晚期的放射虫Helenifore robustum动物群。对于温泉地区该组地层的时代归属,我们认为:由于已发现的中泥盆世珊瑚、腕足类化石主要产于灰岩砾石或外来块体中,因此,这些化石的时代并不代表该组形成的时代;而产于硅质岩透镜体中的晚泥盆世弗拉晚期的放射虫化石很可能代表该组的年代。全文共描述放射虫5属11种,归属3目4科。     

贵州睦化泥盆系—石炭系界线剖面的鱼类微化石

本文记述了贵州睦化泥盆系—石炭系界线上、下两个层位中所发现的7个属种的软骨鱼类、棘鱼类的牙齿和鳞片等微化石,建立了代化瓣齿鲨 (Petalodus daihuaensis, sp. nov.) 和贵州棘鱼 (Acanthodes guizhouensis, sp. nov.) 两个新种.通过研究,划分出两个鱼类微化石组合: 1.上泥盆统顶部(法门阶)以 Phoebotus politus 为代表的鲨类化石组合; 2.下石炭统底部(杜内阶早期)贵州棘鱼化石组合.睦化剖面根据牙形石的研究,泥盆系—石炭系的界线在 Siphonodelle praesuleata 化石带和 S. sulcata 化石带之间.本文记述的鲨类化石组合发现在睦化剖面代化组的最顶部 (GM1120, 1211), 相当于 Siphonodelle praesulcata 化石带;贵州棘鱼发现于格董关层 (GM1124), 在界线之上.在睦化,以及在其他各地, Phoebodus 和 Harpagodens Fero 这样的鲨类皆发现于晚泥盆世.而 Acanthodes 属则从 Siphonodelle sulcata 带起才出现,未发现于更老的地层中.因此 Acanthodes 属的最早出现可能也是石炭系底界的标志.     

云南曲靖地区早泥盆世无颌类化石

云南曲靖地区早泥盆世地层中产无颌类化石早有报导。抗日战争前王曰伦于翠峰山和廖角山(原误称“妙高山”)两地均曾发现头甲角(Cephalaspidae)科化石(丁文江、王曰伦1936—1937;杨钟健1939)。其后,李广源等于廖角山采得的鱼化石经杨钟健鉴定,其中无颌类化石定为 Cephalaspis sp.(李广源等1942,滇东曲靖、沾益地质,未刊稿)。上述化石可惜均未进行古生物学描述,标本于抗日战争期间几经辗转,今已不知下落。     

节甲鱼的一内颅化石

本文记述了广西六景的一长胸节甲类的内颅化石,并和我国已记述的Szuaspis yunnanensis、Kueichowlepis sinensis的内颅作了形态比较,讨论了它们之间的系统关系。     

THE HETEROSTRACAN FISHES

1. The heterostracan fishes were jawless, microphagous, devoid of paired fins and encased in a bony armour. The classification is based on the arrangement of the plates of the carapace — the primitive forms possessed a tessellated armour made up of numerous small polygonal plates. Several genera had a tessellated carapace ventrally but large discrete plates dorsally. All further groups are characterized by distinct patterns of plates which remain constant within each order. The proportions in some species suggest sexual dimorphism. 2. A study of the superficial ornamentation reveals patterns of growth. From the primitive tessellated condition different evolutionary lines can be followed leading to the fusion of these small elements into large discrete plates. Among the latest group of heterostracans there was a secondary redevelopment of tesserae. 3. Impressions on the inner surface of the plates of the carapace enable certain aspects of the internal anatomy to be reconstructed. The nasal sacs were double, the acousticolateralis system was primitive. The brain was little more than the nerve cord swollen in three places, there was no cranial flexure. Impressions of two pre-otic somites were present, indicating that they had not migrated to form the extrinsic eye muscles. The branchial arches appear to have been of gnathostome type and in some genera spiracles were formed as an adaptation to a benthonic mode of life. 4. Microscopic sections of the armour demonstrate the existence of four tissues: aspidin, dentine, enameloid and calcified cartilage. Aspidin was originally acellular but later became cellular; the organic matrix was first organized like dentine, but subsequently like bone. Furthermore aspidin was capable of remodelling. Dentine appears to have acted as a skin-like tissue and was capable of regeneration. The significance of enameloid and calcified cartilage in the dermal armour is not well understood. 5. Until the end of the Silurian the heterostracans inhabited marine waters but from the beginning of the Devonian they colonized the fresh-water lakes and rivers of the Old Red Continent. One major group flourished in a large embayment on the edge of the Tungussian land mass. When the stratigraphical range and geographical distribution of the heterostracans is listed, evolutionary centres can be recognized and also migration routes: during the Upper Silurian the cyathaspids in the Canadian Arctic, the Lower Devonian pteraspids in Eastern Europe, the later Lower Devonian amphiaspids in north-west Siberia (Tungussian Realm), and the Middle and Upper Devonian psammosteids in the Baltic province. Periods of migration from the Baltic to Scotland, the Timan, Ellesmereland, the Urals and Donbas have been documented. For the illustrations the author is indebted to Miss Jennifer Middleton and Mr John Smith.     

REMARKS ON THE STRATIGRAPHY AND MORPHOLOGY OF PRAGUIAN AND PROBABLY YOUNGER MONOGRAPTIDS

Praguian and probably younger graptoloids as well as the early Lower Devonian (Lochkovian) graptoloids are known from all continents except Antarctica and South America. At least five to six graptolite zones can now be distinguished in the Lower Devonian. In comparison with the Lochkovian faunas, the medial to late Lower Devonian graptoloid communities are considerably impoverished and composed exclusively of Monograptus species of the M. uncinatus group. Lino-graptus and Abiesgraptus , which are characteristic of much of the Lochkovian, are lacking in Praguian (and younger) strata. Monograptus pacificus from the southeast Alaskan Karheen Formation appears to be the youngest true graptolite known to date, possibly having a stratigraphic position not far away from the Lower/Middle Devonian boundary.     

First report of brachiopod–brachiopod endoparasitism

Schemm-Gregory, M. & Sutton, M. 2010: First report of brachiopod–brachiopod endoparasitism. Lethaia , Vol. 43, pp. 111–115.
The first example of brachiopod–brachiopod endoparasitism is reported from the Lower Devonian of China. Three-dimensional reconstructions following serial sectioning show a specimen of a strophomenide ( Dicoelostrophia sp.) within an articulated shell of the spiriferide Rostrospirifer tonkinensis ; morphological modifications of the host and the positioning of the strophomenide with respect to the inhalant current demonstrate the in vivo nature of the association. The symbiosis is interpreted as parasitic; it appears to be facultative but demonstrates the viability of this mode of life, expanding the ecological range known to be exploitable by the Brachiopoda. □ 3-D reconstruction , Brachiopoda , Dicoelostrophia , endoparasitism , Lower Devonian , Rostrospirifer .     

A Lower Devonian hexacrinitid crinoid (Camerata,Monobathrida) from south-west England

The most species-rich and widespread crinoid clade in the type area of the Devonian of south-west England is the monobathrid camerate family Hexacrinitidae Wachsmuth and Springer. These crinoids occur either as thecae (Middle Devonian) or pluricolumnals and columnals (Lower to Upper Devonian). The first new, nominal species of hexacrinitid, probably Oehlerticrinus Le Menn, to be described from this region since the nineteenth century is Oehlerticrinus peachi sp. nov. from the Lower Devonian Looe Basin of southern Cornwall. This specimen is mouldic and somewhat flattened, retaining the proxistele and arms. Diagnostic features include the heteromorphic proxistele with circlets of long, unbranched radices directed towards the crown; the high, box-like (=skyphosiform) theca with a flattened base; a thecal plate sculpture of tubercles and ridges arranged in triangles; and the pinnulate arms. Any uncertainty in identifying this species at the generic level rests with the arms being pinnulate, not ramulose as is common in Hexacrinites Austin and Austin, indicating that O. peachi is closer to Oehlerticrinus Le Menn.     

Sedimentary environment of Devonian pelagic limestones in the Southern Alps

Primary sedimentary structures combined with the geometry of Devonian and Lower Palaeozoic lithosomes in the Southern Alps (Austria and Italy) suggest many doubts about the published environmental and bathymetric interpretation of some Lower to Middle Devonian pelagic nodular limestones as 'deep-water' abyssal deposits. Every graded bed is not necessarily aturbidite; a single or some turbiditic beds are not necessarily deep-water or abyssal deposits; carbonate dissolution does not necessarily take place only below the carbonate compensation depth (CCD). Data show that graded allodapic beds, like those of the Lower to Middle Devonian of the Alps, may have been deposited as storm layers at a depth not exceeding some hundreds of metres. Accordingly the margins between Lower Devonian shallow-water platform and basins were characterized by low gradient and transitional sedimentary conditions. They became very steep only at the Devonian–Carboniferous transition because of synsedimentary block faulting.     

PTERYGOTUS ANGLICUS AGASSIZ (CHELICERATA: EURYPTERIDA) FROM ATHOLVILLE, LOWER DEVONIAN CAMPBELLTON FORMATION, NEW BRUNSWICK, CANADA

Abstract:  Specimens of the large eurypterid Pterygotus from the Early Devonian Campbellton Formation outcropping at Atholville, New Brunswick, are identified as Pterygotus anglicus Agassiz. The locality, in the Atholville beds near the western end of the Campbellton Formation exposure, is best known for its vertebrate fauna of ostracoderms, arthrodires, acanthodians and chondrichthyans, first described in 1881. Although a significant series of pterygotid fossils was acquired by the Natural History Museum, London, in 1892, it received little attention. A few small specimens from the Geological Survey of Canada collections were named Pterygotus atlanticus by Clarke and Ruedemann, considered here to be an invalid taxon. They suggested that P. atlanticus might turn out to be a small specimen of P. anglicus . The new material described here, including one relatively complete individual, confirms their suspicions and provides evidence of Pterygotus anglicus in the Lower Devonian of North America.     

A new actinolepid arthrodire (Class Placodermi) from the Lower Devonian Sevy Dolomite, East-Central Nevada

A new genus and species of actinolepid arthrodire, Aleosteus eganensis , is described from the Lower Devonian (Late Emsian) Sevy Dolomite in the Egan Range of east-central Nevada. A cladistic analysis of the family Actinolepidae is presented for the first time and shows the Baltic Actinolepis species form the primitive sister-group of all other actinolepids. Rapid evolution of the Actinolepidae during the Lochkovian is reflected in the dispersal of the family around the Old Red Sandstone Continent at this time followed by the development of endemic faunas through the Lower Devonian and into the Middle Devonian.     

广西泥盆纪的窄鳞鱼类化石

本文记述了采自广西南宁、横县、博白等地的窄鳞鱼类(Arctolepida)的一些标本。根据它们的形态特征的比较,暂分别归属于一新属新种,郁江拟威氏鱼(Parawilliamsaspis yuiangen-sis gen.et sp.nov.);菲里克特鱼亚科的未定属种(Phlyctaenaspinae indet.);窄鳞鱼类的胸刺。对于这些化石的古地理学及地层对比上的意义,也作了初步的讨论。