Aspects of crinoid palaeontology of the North Esk Inlier,Scotland (Silurian,Llandovery, Telychian)

Abstract: The described fauna of well‐preserved Llandovery (Telychian) echinoderms from the North Esk Inlier, including six crinoids, one echinoid and seven starfish species, is mainly allochthonous. Most of these taxa are known only from starfish beds, channel fill deposits probably representing submarine mass flows and preserving a biota probably derived from elsewhere, presumably shallower water. Only one crinoid species, Pisocrinus cf. campana Miller, is recognized as a common fossil away from the starfish beds and is a biostratigraphic marker for the base of the Wether Law Linn Formation, forming part of the Skenidioides‐Cyrtia Association. Crinoid columnals preserved perpendicular to bedding (that is, in putative life position) in Lamont’s bivalve bed, Deerhope Formation, are tentatively interpreted as being in situ by comparison with a similar occurrence in the Silurian of Arisaig, Nova Scotia. Two new species of crinoid are described, the cladid Dendrocrinus? sp. and the columnal morphospecies Pentagonocyclicus (col.) lamonti sp. nov.     

LATE ORDOVICIAN BRACHIOPODS FROM THE DULANKARA FORMATION OF THE CHU-ILI RANGE, KAZAKHSTAN: THEIR SYSTEMATICS, PALAEOECOLOGY AND PALAEOBIOGEOGRAPHY

Abstract:  Brachiopods from the late Ordovician (late Caradoc) Dulankara Formation of the Chu-Ili Range, Kazakhstan, are reviewed. Those from the upper two members of the formation, the Degeres and Akkol members, are systematically described. New genera from the Dulankara Formation are Nikitinamena (Plectambonitoidea: Leptellinidae), with type species Nikitinamena bicostata sp. nov., and Weberorthis (Orthoidea: Plectorthidae), with type species Mimella brevis Rukavishnikova. Another new genus is Glyptomenoides (Strophomenoidea: Glyptomenidae), with type species Rafinesquina girvanensis Salmon from the Caradoc of Girvan, Scotland. Other new species from the Dulankara Formation are Holtedahlina orientalis , Platymena tersa , Christiania proclivis , Leangella ( Leangella ) paletsae , Metambonites subcarinatus , Ogmoplecia nesca and Plectorthis licta . The ecology and assemblages of all three members of the Dulankara Formation are identified or reviewed, and their palaeogeographical significance assessed: the Chu-Ili Terrane (on which the Dulankara Formation was situated during the Ordovician) formed part of the relatively low-latitude peri-Gondwanan complex of terranes, and was probably not far from North and South China. The faunal links suggested between the Dulankara brachiopods and contemporary faunas from Australia are now perceived to be weaker than previously thought.     

川南布拖县乌科志留纪早期介形类丽足介目(Myodocopida)

乌科剖面位于四川布拖县乌科乡境内。在此剖面的石门坎组上碎屑岩段中产有相当丰富的介形类丽足介目,特别是球茎介科的化石。经研究、鉴定,初步划分出2个属和6个种,其中包括3个新种(Entomozoe bispinosa sp.nov.,E.suboblongasp.nov.,E.wukeensis sp.nov.),1个比较种和2个未定种。在分析上述属、种,特别是相关种的地质、地理分布特征的基础上,并参考其他门类化石(如腕足类动物群)和岩石性质,提出石门坎组上碎屑岩段可能要低于笔石M.crispus带上部,大致相当于志留纪兰多维列世特列奇期早期。Entomozoe和球茎介科的最早代表推测是产自石门坎组上碎屑岩段Entomozoe的那些分子,如E.suboblongasp.nov.,而非E.tuberosa(Jones),1861(或其亲缘种E.aff.tuberosa)(Siveter et al.,1990,2006)。文中还就上述丽足介目动物群的生态环境进行了分析,指出石门坎组上碎屑岩段可能是在陆棚浅水到相对较深水、能量较低的、温暖的开阔海环境下沉积的。     

Dissepiments in the graptolite Monograptus turriculatus

An example of the graptolite Monograptus turriculatus (Barrande, 1850) from the crispus Biozone (Silurian, Llandovery) of the Girvan district, Scotland, shows the first recorded instance of dissepiment formation in graptoloid graptolites. The dissepiments are formed by the fusion of thecal spines with the dorsal wall of the adjacent part of the succeeding whorl of this spiral graptolite. The formation of these structures appears easiest to envisage using models of the graptolite colony that do not involve extrathecal tissue. □ Graptolithina , Monograptus, morphology, functional morphology, Silurian, Llandovery.     

Llandovery sporomorphs and graptolites from the Manbo Formation,the Mojiang County,Yunnan, China

Llandovery sporomorphs and graptolites have been recovered from the Manbo Formation, Mojiang area, western Yunnan, China, which belonged to the Indo-China Palaeoplate in the Palaeozoic. The graptolite fauna, including 8 genera and 12 species, is considered Mid Telychian, Llandovery in geological age, confirming the existence of Llandovery rocks in this region. The Silurian stratigraphical sequence of this area is reconsidered as in the ascending order: Manbo Formation (Llandovery–early Wenlock), Shuiqing Formation (late Wenlock–Ludlow) and unnamed formation (Pridoli?). The sporomorph assemblage from the Manbo Formation includes seven species in five genera. The dominant members of this assemblage are Tetrahedraletes medinensis and Laevolancis chibrikovae. Based on the low diversity and low abundance, the geological age of this assemblage is considered to be approximately the Telychian, Llandovery. The parent plants of sporomorphs probably inhabited the landmass near Mojiang area, these sporomorph-producing plants probably included bryophyte-like land plants and primitive vascular land plants. The sporomorph evidence shows that the South China and Indo-China palaeoplates may have been in close proximity (maybe with some continental bridges linking them) to each other at least in the Llandovery. They were also closely related with Gondwanaland in the Llandovery.     

Probing the deep shelf: a Lagerstätte from the Upper Ordovician of Girvan, southwestern Scotland

A deep‐water Konservat Lagerstätte from the lower Caradoc (Sandbian) at Girvan is dominated by the trilobite Diacanthaspis trippi, the carpoids Anatifopsis n. sp.? and a new genus of ctenocystoid together with the polyplacophoran Solenocaris solenoides and the brachiopod Onniella williamsi. Most of these are multi‐element organisms, with many specimens preserved in an articulated state in finely laminated rocks, indicating minimal disturbance and suggesting that the fauna is largely an in situ association. It contains few of the species known from other deep‐water sites of similar age at Girvan which contain diverse assemblages of trilobites and brachiopods absent from the Lagerstätte. The taphonomy of the site indicates preservation by rapid burial followed by early diagenesis under dysaerobic conditions. It provides a ‘taphonomic window’ on otherwise unknown faunas from distal shelf facies on the Ordovician Laurentian margin, and, moreover, is an important reminder of the hidden biodiversity that resided in thin‐shelled, multi‐element organisms.     

Huemacaspis (Trilobita, Kerfornellinae) from the Late Ordovician of the Argentine Cordillera Oriental

The trilobite genus Huemacaspis P?IBYL and VANěK, 1980 is redescribed from well-preserved material from the Santa Gertrudis Formation (early Caradoc), Argentine Cordillera Oriental. The new species H. gallinatoensis is described and figured. Huemacaspis is widely distributed in the southern part of the Central Andean basin during the early Caradoc and it is a key taxon for the correlation of different units from the Cordillera Oriental and Sierras Subandinas of Argentina and the Cordillera Oriental of Bolivia. This taxon is one of the few records of trilobites of early Caradoc age found in the shallow shelf environments of southwestern Gondwana. Huemacaspis is accommodated within the Kerfornellinae, a subfamily otherwise known from southern Central Europe and northern Africa. The trilobite fauna from the early Caradoc of the Central Andean basin suggests a faunal exchange with the latter regions indicating the persistence of a broadly similar biogeographic pattern to that documented in earlier Ordovician times.     

Neogene paleobiogeography and East African paleoenvironments: contributions from the Tugen Hills rodents and lagomorphs.

A minimum of 28 genera of rodents and one genus of lagomorph were recovered from the Tugen Hills, Baringo District, Kenya, from localities dating from over 15.5 to about 4.4 Ma. The middle Miocene (sites dated between 15.8 and 15.3 Ma) rodent fauna recovered primarily from the Kipsaramon site complex, Muruyur Formation, includes a mixture of characteristically early Miocene taxa, and more derived forms. Composition of the African rodent fauna changes dramatically with the introduction of myocricetodontines, democricetodontines, and dendromurines, immigrants primarily from southern Asia. In the Tugen Hills, these taxa are first found in the Kabasero localities, Ngorora Formation, at sites dating from 12.5-12.33 Ma. A second major change in the African rodent fauna reflects the introduction of murines, immigrants from southern Asia. In the Tugen Hills murines are first encountered at Kapcheberek, Lukeino Formation, dated to 5.9-5.7 Ma. One rodent genus from the Lukeino Formation (Arvicanthis), and two from the Tabarin locality, Chemeron Formation (Heliosciurus, Paraxerus; 4.5-4.4 Ma), represent the earliest records of these extant African genera. A cricetomyine from the Ngorora Formation (12.5 Ma) is likely the earliest report of this exclusively African group. One of the earliest African records of porcupines (Hystricide) is from the Lukeino Formation. Lagomorphs are poorly represented, but include one of the earliest African occurrences of the family Leporidae from the Mpesida Beds (bracketed by dates of 7-6.2 Ma), and possibly a new genus of leporid from the Kapcheberek locality. Analysis of the Tugen Hills small mammals in association with other African records suggests several episodes of dispersal between Africa and Eurasia during the middle and late Miocene. Rodents from Kipsaramon are indicative of forests in conjunction with more open habitats. Those from the Kapcheberek locality are suggestive of a savanna habitat. The rodents from the Tabarin locality suggest a woodland environment.     

上扬子区奥陶纪三叶虫属Hexacopyge的新材料

描述上扬子区鄂西和湘西中及晚奥陶世桨肋虫类三叶虫Hexacopyge的 5个种 ,包括 2新种 ,即H .turbiniformis和H .yichangensis;讨论Hexacopyge的定义及其与相关属的关系。Hexacopyge在区内分布广、演化快 。     

Age of the Silurian Wuxiahe Formation in Langao,Northwest China: New conodont data

A recent study of conodonts from the Wuxiahe Formation (lower to middle part) in the Ziyang-Langao region suggested its age of middle Telychian (Llandovery) to lower Sheinwoodian (Wenlock), contradicted by subsequent graptolite studies indicating an age of late Telychian for the same interval. New samples from the Qiaoxi section for conodonts to re-access the age of the Wuxiahe Formation collected in this study show that the lower to middle part of the formation belongs to the Pterospathodus amorphognathoides amorphognathoides Biozone, suggesting the age of late Telychian; thus, the Llandovery–Wenlock boundary in the section is most probably higher than previously estimated, but its precise position is not determined since the identification of the Wenlock graptolite Cyrtograptus cf. lundgreni in the section is to be further confirmed. Based on the conodont faunas recognized in the Qiaoxi and Tianwancun sections, the base of the Wuxiahe Formation in the Ziyang-Langao region is diachronous, i.e., not higher than the upper Telychian Pterospathodus amorphognathoides amorphognathoides Biozone at Qiaoxi, but not lower than the lower Sheinwoodian Kockelella ranuliformis Biozone at the Tianwancun setion.     

Silicified Upper Ordovician trilobites from Pai‐Khoi,Arctic Russia

Abstract: A collection of silicified trilobites extracted from samples obtained by F. Nansen from the Upper Ordovician of Khabarovo, Pai Khoi, Russian Arctic is dominated by two new species of the proetide Lasarchopyge, a genus known hitherto only from the Argentine Precordillera. Comparison of Lasarchopyge with Scharyia reveals a range of common characters that support inclusion of both genera in the same family. The rest of the fauna comprises a metagnostid (Trinodus elspethi), an asaphid (Isotelus sp.), two remopleuridids (Remopleurides cf. caelatus and R. sp. nov. A), an aulacopleurid (Harpidella triloba), a lichid and an odontopleurid (Apianurus cf. barbatus), the last two being represented by very fragmentary material. T. elspethi, H. triloba, R. cf. caelatus and A. cf. barbatus are common to or closely resemble taxa from the Edinburg Formation, Virginia. Closely related taxa are present also in the Esbataottine Formation, NW Territories, Canada, and in the Albany Group, Girvan district, Scotland. All of these occurrences are of early Caradoc (Sandbian) age, and most lay at palaeolatitudes of 20°–30° south; all are interpreted as having been deposited on the outer shelf, which is consistent with their distribution.     

Cryptospore Assemblages from the Ordovician/silurian Boundary in the Puna Region, North-west Argentina

Palynomorph assemblages have been recovered from deposits believed to straddle the Ordovician/Silurian boundary, from the upper member of the Salar del Rincón Formation, in the Puna region of north-west Argentina. The palynomorph assemblages are dominated by terrestrial cryptospores, but also contain marine elements (acritarchs, prasinophycean algae and chitinozoans). The cryptospore assemblages are similar in composition to those described from coeval deposits worldwide, suggesting that the producers were cosmopolitan and tolerated a wide range of climatic conditions. They are correlated with the Imperfectotriletes spp. Interval Biozone (sub-biozone α) of the Imperfectotriletes spp.- Laevolancis divellomedia Assemblage Biozone, indicating a Hirnantian (latest Ordovician) age. Acritarchs include late Ordovician species such as Eupoikilosusa striata and Villosacapsula cf. setosapellicula , that coexist with the Llandovery species Dactylofusa estillis. Based on lithological and palynological evidence, an early Llandovery, or a late Hirnantian (post-glacial) age is proposed for the basal part of the upper member of the Salar del Rincón Formation.     

Les assemblages de graptolites du llandovery dans le synclinorium du Ménes-Bélair (Massif Armoricain)

Ampelites in the lower member of the Formation 0839 de la Lande-Murée (Silurian of the Ménez-Bélair Syncline) have yielded rich and well-preserved graptolite faunas. This material, and that in older collections, indicates the presence of all or part of the Turriculatus, Crispus and Griestoniensis Zones. Earlier Llandovery graptolite zones are not represented in the Ménez-Bélair Syncline and breaks encompassing the Lower Llandovery and the earliest part of the Upper Llandovery is envisaged.     

Aeronian (Llandovery, Lower Silurian) palynomorphs and graptolites from the Lipeón Formation, Eastern Cordillera, north-west Argentina

The lower levels of the Lipeón Formation, in the Eastern Cordillera, north-west Argentina, yield a marine-dominated palynomorph assemblage, together with graptolites of mid to late mid Llandovery age (Demirastrites convolutus and probably Stimulograptus sedgwickii zones). The palynomorph assemblage is dominated by acritarchs, but also contains algae and terrestrial cryptospores. Crassiangulina variacornuta, considered a potentially good global biostratigraphical marker for the Upper Llandovery is recovered for the first time from the Silurian of Argentina. The occurrence of this species in strata not younger than late Aeronian, and independently dated by graptolites, indicates an early first appearance for Crassiangulina variacornuta, in the Lipeón Formation, below the Aeronian/Telychian boundary. The lower part of the unit corresponds to a quiet marine environment; thus supporting that Crassiangulina variacornuta is a facies-sensitive acritarch.     

NEW CRINOIDS (ECHINODERMATA) FROM THE LLANDOVERY (LOWER SILURIAN) OF THE BRITISH ISLES

Abstract:  British Llandovery crinoids remain poorly known. Three species are documented herein that were originally described, but not published, by W. H. C. Ramsbottom. Clematocrinus ramsbottomi Fearnhead sp. nov. (Tortworth Inlier, Gloucestershire; Telychian) has a heteromorphic column, N434243414342434, radices directed away from the crown, and ten long, uniserial arms with a pustular aboral sculpture and long, slender pinnules. Clematocrinus spp. are widely distributed in the Silurian of England. Ptychocrinus mullochillensis Fearnhead and Donovan sp. nov. (Girvan district, Strathclyde; Rhuddanian) is the second report of this Upper Ordovician–Lower Silurian genus from outside North America. Although incompletely known, this species is distinguished by its hidden infrabasals, 20 arms and sunken interbrachial plates with a strongly stellate sculpture. Petalocrinus bifidus (Bather MS) Donovan and Fearnhead sp. nov. (Woolhope Inlier, Herefordshire; Telychian) is locally common enough to give its name to a mappable lithostratigraphic unit, the Petalocrinus Limestone. Unlike other Petalocrinus species known from the Silurian of China, northern Europe and North America, the fused arms of P. bifidus are divided in two by a proximal adoral ridge and an associated distal notch. Unlike extant crinoids, Petalocrinus probably lived as a rheophobe; the fused arms may have acted to deter predators.     

湖北宜昌地区晚奥陶世三叶虫动物群及分带序列

从湖北宜昌黄花场和普溪河桥宝塔组剖面获得的新材料,极大地丰富了华南晚奥陶世三叶虫动物群内容,包括22属、1亚属、31种之多。新材料保存完美,很大程度上完整了有关三叶虫的形态特征。RemopleuridesamphitryonoidesLu,1975一种由于新发现了活动颊、唇瓣、胸部及尾部,证明它确实是Remopleurides的成员,排除了对该种归属的怀疑。文中建立了1新属和2新种:Pentacopygepuxiheensisgen.etsp.nov.,Lamproscutellum?limbatumsp.nov.。同时,以桨肋虫类为基础在宝塔组Nankinolithus带之下进一步划分出4个三叶虫带,从下到上依次为Pentacopygepuxiheensis间隔带,Hexacopygeyichangensis间隔带,Remopleuridesamphitryonoides延限带(普溪河段,卡拉道克中期),和Dislobosaspisguizhouensis延限带(临湘段下部,卡拉道克晚期)。     

Chitinozoan biostratigraphy of the basal Wenlock Series (Silurian) Global Stratotype Section and Point

Diverse and abundant assemblages of chitinozoans allow the recognition of the upper part of the Margachitina margaritana Biozone in the uppermost Llandovery and lowermost Wenlock series of the Hughley Brook section. The Cingulochitina bouniensis and Salopochitina bella biozones are identified in the lower part of the Buildwas Formation, Wenlock Series. The chitinozoan data indicate that the base of the Wenlock Series most probably correlates with a level in the upper centrifugus or lower murchisoni graptolite biozones. Chitinozoans also indicate that the base of the riccartonensis graptolite Biozone may occur within the Buildwas Formation and not the overlying Coalbrookdale Formation.     

Evaluation of the Salinic I tectonic, Cancañiri glacial and Ireviken biotic events: Biochemostratigraphy of the Lower Siluriansuccession in the Niagara Gorge area, Canada and U.S.A.

Well-preserved brachiopods from the Niagara Gorge area, Anticosti Island, Britain, Gotland and Estonia were utilised to delineate a complex isotopic evolution for Llandovery-Wenlock seawater. The Sr-isotope record reflects the Salinic I tectophase of the Late Llandovery in the continuous increase in ⁸⁷Sr/⁸⁶Sr values from 0.708070 to 0.708346. The Salinic II tectophase is marked by relative constancy of Sr isotope values until the Late Wenlock when it rises from 0.708345 to 0.708430. The second tectonic phase was therefore likely only of a regional nature. The carbon isotopes during the Llandovery fall within a band of about − 1‰ to + 3‰, a range comparable to modern low-latitude brachiopods. A large positive δ¹³C excursion of about 3‰, identifies the Ireviken event/excursion, characterizes the Early Wenlock. The biotic crisis and the isotope excursion itself may be ultimately related to the onset and duration of the Cancañiri glaciation, although a direct causative scenario is as yet unknown. The oxygen isotopic trends of well-preserved brachiopods clearly reflect a warm climate interval during the latest Llandovery associated with the Silurian sea level highstand. Subsequently, in the Early Wenlock, the sea level fell with the onset of the Cancañiri glaciation in the southern hemisphere. This is reflected in a significant positive δ¹⁸O excursion, particularly in brachiopods from the Niagara Gorge area. Brachiopods from lower latitudes were awash in warm tropical currents and therefore exhibit somewhat more negative δ¹⁸O values, indicating a lesser cooling gradient.     

First record of a middle pliocene hominid from the Siwalik Hills of South Asia

The Siwalik Hills have yielded what is perhaps the world’s most ancient early hominid. In December 1992 I discovered a hominid mandibular ramus and a hominid femur in association with stone tools in the Tatrot Formation of the upper Siwalik. The discovery was made from the Tatrot Formation exposed at Khetpurali Village in Haryana, North India. The teeth are bunodont, having a lingually inclined wear plane. The P3 is molariform and single rooted. The femur is platymeric and has medullary stenosis. The stone tools are chopper types. Magnetostratigraphic dating of the Tatrot Formation ranges from 2.47 Myr at the top to 5.44 Myr at the base. The hominid — yielding bed is dated at 3.40 Myr — Middle Pliocene. The palaeoecology of the Tatrot Formation suggests open savannah. The discovery will cast new light on the origin and migration of the early hominids, and hopefully will contribute to a solution of the 100-year-old dispute about the African or Asian origin of humans.     

Early Silurian(Telychian)rugose coral fauna of Daguan area, northeast Yunnan Province,China

Study on rugose coral fauna of the Sifengya Formation(early Telyehian)and Daluzhai Formation (mid-late Telychian)in Daguan area,northeast Yunnan Province,China was carded out.Rugose coral fauna of the Sifengya Formation included 18 genera and 34 species,while Daluzhai Formation with nine genera,ten species.We described rugose coral fauna(12 genera,19 species)including one new genus and five new species,i.e.Protoketophyllum daguanense gen.et sp.nov..Crassilasma huanggexiense sp.nov.,Pseudophaulactis heae sp.nov.,P.convolutus sp.nov.,and Shensiphyllum minor sp.nov..The characteristics and geological significance of rugose coral fauna of Sifengya Formation and Daluzhai Formation were analyzed.Particularly,mgose coral fauna of the Sifengya Formation represent early Telychian rugosan fauna in the Upper Yangtze region and improve the sequences of early Silurian(Llandovery)mgose coral assemblages in Yangtze region.It is therefore very meaningful to further analyze radiation period of rugose coral fauna in such epoch.