Showing papers in "Palaeontology in 2001"
TL;DR: The body mass estimation of several limb bone dimensions (shaft cross‐sectional properties, articular sizes, and bone lengths) were examined using bivariate linear regression analyses to identify hyaenodontid creodonts from the Eocene–Oligocene of North America.
Abstract: The body mass estimation of several limb bone dimensions (shaft cross-sectional properties, articular sizes, and bone lengths) were examined using bivariate linear regression analyses. The sample included taxonomically and behaviourally diverse small to medium-sized Recent carnivorans and carnivorous marsupials. All examined limb bone dimensions indicated low errors (percentage standard error of estimate, 8–13) for the body mass estimations. Among them, humeral and femoral shaft properties correlated best with body weight, while limb bone lengths gave larger errors. Both humeral and femoral head dimensions have relatively large individual variations, and distal humeral articular dimensions seem to be influenced more by phylogenetic differences. The regressions based on each locomotor group gave slightly lower errors than those based on the total pooled sample. The results were then applied to hyaenodontid creodonts from the Eocene–Oligocene of North America. The estimated body masses (kg) are: Arfia, 5.4–9.5; Prototomus, <6.0; Pyrocyon, 2.6; Sinopa, 1.3–1.4; Tritemnodon, 7.6–13; Prolimnocyon, 1.6; Thinocyon, 0.7–2.5; Machaeroides, 12; Limnocyon, 7.8– 16; Hyaenodon, 9.1–43. The various limb bone dimensions give different body mass values, but the variation in estimates is smaller compared to those derived from dental or cranial measurements.
101 citations
TL;DR: It is concluded that microprismatic enamel made its appearance only once in the Cimolodonta and might have originated from unknown members of the Paracimexomys group with separated molar cusps and smooth enamel.
Abstract: We present a synopsis of high-rank multituberculate systematicsand a manually generated cladogram illustrating multituberculate interrelationships. We divide the Multituberculata into the paraphyletic suborder ‘Plagiaulacida’, an apparently monophyletic suborder Cimolodonta, and one family incertae sedis. Within ‘Plagiaulacida’ we recognise three informal lines: paulchoffatiid (three families), plagiaulacid (three families) and allodontid (two families and the genus Glirodon). The Cimolodonta are divided into an informal Paracimexomys group; three superfamilies: Ptilodontoidea, Djadochtatherioidea (new), and Taeniolabidoidea (restricted to Taeniolabididae); and five families (superfamily incertae sedis): Eucosmodontidae, Microcosmodontidae, Cimolodontidae, Boffiidae, and Kogaionidae; and some genera incertae sedis. New characters used in our analysis are (1) a tendency of molar cusps to coalesce; and (2) ornamentation of grooves, pits, and ridges on the molars. We argue that the Ptilodontoidea, and less certainly also the Cimolodontidae and Boffiidae, might have originated from amongthe plagiaulacid line, a possible intermediate link being the Paracimexomys group. The remaining Cimolodonta might have originated from unknown members of the Paracimexomys group with separated molar cusps and smooth enamel. The origin of two types of prismatic enamel and a relationship between them are stumbling blocks in understanding the origin of the Cimolodonta; we conclude that microprismatic enamel made its appearance only once. Revised diagnoses of high-rank multituberculate taxa, including lists of all known genera, are given.
98 citations
TL;DR: Scoyenia beerboweri is a new species of burrow from the late Ordovician (Ashgill) Juniata Formation in central Pennsylvania, USA as mentioned in this paper.
Abstract: Scoyenia beerboweri is a new ichnospecies of burrow from the late Ordovician (Ashgill) Juniata Formation in central Pennsylvania, USA. The burrows are abundant in red calcareous palaeosols, and were created by animals living at the time of soil formation, because they are filled with red sediment like that of the palaeosol matrix, and both cut across, and are cut by, nodules of pedogenic carbonate. The isotopically light carbon and oxygen of carbonate in the palaeosols indicate a terrestrial ecosystem of well-drained floodplains in a tropical seasonally-dry semi-arid palaeoclimate. Backfill layering within the burrows is evidence of a bilaterally symmetrical animal. Size distribution of the burrows reveals discontinuous growth, as found in arthropods. Ferruginized faecal pellets in the burrows indicate that they ingested sediment. For these reasons the burrows of Scoyenia beerboweri are most likely to be the work of millipedes. The nature of vegetation supporting them is unknown, although a single problematic plant-like fossil cast was found, and liverwort spores are widespread in rocks of this age. Vegetative biomass was limited judging from the degree of chemical weathering, extent of burial gleization and isotopic composition of carbon in the palaeosols. These distinctive respiration-dominated liverwort-millipede polsterlands lived at a time of global greenhouse climate, following Precambrian–Cambrian lichen-algal microbial earths and supplanted by Silurian brakelands of early vascular land plants.
91 citations
TL;DR: The first comprehensive taxonomic revision of the wood flora from Livingston Island is presented and the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous is discussed.
Abstract: The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity (Sahnioxylon; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov.
74 citations
TL;DR: The available data on shell microstructure as well as most conchological characters do not support a close relationship between Ostreidae, Plicatulidae and Dimyidae.
Abstract: Based on new material from the Upper Triassic Nayband Formation of east-central Iran and on type material from the Alpine Triassic, the taxonomy of the cementing bivalve families Prospondylidae, Plicatulidae, Dimyidae and Ostreidae is examined and their phylogenetic relations are discussed. The Prospondylidae are characterized by the presence of an early pectiniform stage in their Palaeozoic genera which disappeared in most later forms due to ontogenetic pre-displacement of cementation. The Plicatulidae probably evolved from an ancestor within the Prospondylidae by the formation of strong crura, which allowed the reduction of the lateral part of the ligament. Their hinge was later modified by shifting resilifer and crura in a ventral direction and by forming a secondary ligament dorsally. The emended genera EoplicatulaPseudoplacunopsis represent different early stages of this development. The species Eoplicatula parvadehensis sp. nov. and Pseudoplacunopsis asymmetrica sp. nov. from the Nayband Formation are described. The shell of some early Ostreidae is characterized by the lack of structural chambers and by the presence of an originally aragonitic inner shell layer. For such forms, the new genus Umbrostrea is proposed, and the new species Umbrostrea emamiiUmbrostrea iranica are described. The available data on shell microstructure as well as most conchological characters do not support a close relationship between Ostreidae, Plicatulidae and Dimyidae.
65 citations
TL;DR: Riograndia guaibensis gen et sp nov as discussed by the authors, represented by a fragmentary skull and a lower jaw bearing a complete dentition, shows a more generalized morphology than Chaliminia from the Upper Triassic of Argentina and PachygenelusDiarthrognathus from the Lower Jurassic of South Africa, Canada and Greenland.
Abstract: A primitive ‘ictidosaur’ from lower Norian beds of southern Brazil, Riograndia guaibensis gen et sp nov, represented by a fragmentary skull and a lower jaw bearing a complete dentition, shows a more generalized morphology than Chaliminia from the Upper Triassic of Argentina and PachygenelusDiarthrognathus from the Lower Jurassic of South Africa, Canada and Greenland The frontal bone borders the orbit, and ventrally contacts the dorsal process of the palatine The secondary bony palate extends back to the last postcanine I1 and i2 are reduced, whereas I2-3 and i1 are hypertrophied Both PC 1–7 and pc 1–7 have blade-like crowns without cingula and with 5–9 small sharp cuspules The upper postcanine crowns are semicircular in labial view with the cuspules around their margins The lower postcanine crowns are asymmetrical with most of the cuspules dorsodistally distributed The possible origin of this peculiar dentition is interpreted as the retention of the juvenile dentition of ancestors The hypothesis that Riograndia guaibensis and the so-called ‘ictidosaurs’ might have been derived from gomphodont cynodonts is presented
60 citations
TL;DR: In this paper, the authors report on three-dimensional preserved acritarchs from the Doushantuo phosphorites at Weng'an in Guizhou Province and, for the first time, from Baokang in Hubei Province.
Abstract: During the last two decades, a diverse assemblage of multicellular algae, spherical microfossils, bacteria and cyanobacteria (the Weng'an Biota) has been reported from the Terminal Proterozoic Doushantuo phosphorite in south China, which provides an important window for evolutionary studies of multicellular life just before the Ediacaran animal radiation. In this paper we report on three-dimensionally preserved acritarchs from the Doushantuo phosphorites at Weng'an in Guizhou Province and, for the first time, from Baokang in Hubei Province. Our assemblage contains species of the genus Meghystrichosphaeridium Zhang, Yin, Xiao and Knoll, 1998 non Chen and Liu, 1986 including M. chadianensis (Chen and Liu) Zhang, Yin, Xiao and Knoll, emend. 1998, and M. reticulatum Xiao and Knoll, 1999; the genus Echinosphaeridium Knoll, 1992 including the species E. maximum (Yin) Knoll, 1992; the new genus Bacatisphaera including the new species B. baokangensis and the new genus Castaneasphaera including the new species C. speciosa. The latter shows a marked resemblance to similarly preserved phosphatized Palaeozoic acritarchs called ‘mazuelloids’, consistent with a phytoplanktonic mode of life for the global Doushantuo/Pertatataka microflora (DPM).
59 citations
TL;DR: The Maastrichtian Qahlah Formation of the Oman Mountains, a sequence of coarse siliciclastic sediments deposited on a shallow marine shelf above wavebase and at an equatorial palaeolatitude as mentioned in this paper contains intercalated carbonate hardgrounds and other hard substrates which were encrusted and bored.
Abstract: Skeletal encrusters and carbonate hardgrounds are rare in siliciclastic sands and gravels because of high levels of abrasion and sediment movement. An exception to this is the Maastrichtian Qahlah Formation of the Oman Mountains, a sequence of coarse siliciclastic sediments deposited on a shallow marine shelf above wavebase and at an equatorial palaeolatitude. This unit contains intercalated carbonate hardgrounds and other hard substrates which were encrusted and bored. The hard substrates, comprising carbonate and silicate clasts, calcareous bioclasts (mollusc shells and coral fragments) and wood, supported a diverse encrusting and boring fauna dominated in biomass by the oyster Acutostrea. There are twelve bryozoan species and at least two serpulid worm species, most living cryptically. Other encrusters on exposed surfaces include the agglutinated foraminiferan Placopsilina and several species of colonial corals. Borings in the carbonate clasts and shells are predominantly those of bivalves (Gastrochaenolites), with subsidiary clionid sponge (Entobia) and acrothoracican barnacle (Rogerella) borings. The woodgrounds are thoroughly bored by teredinid bivalves (Teredolites). Of the common substrate types, carbonate hardground clasts support the greatest number of taxa, followed by chert clasts, with limestone rockground pebbles being depauperate. Clast composition and relative stability probably explain these differences. Individual clasts probably had variable and typically long colonisation histories. Detailed palaeoecological interpretation is constrained by taphonomic loss, time-averaging and clast transportation and reorientation. Evidence from the Qahlah Formation shows that tropical rocky-shore biotas in the Cretaceous were not impoverished as previously believed.
57 citations
TL;DR: This material represents the second oldest record for the caecilians, after the Jurassic Eocaecilia of North America, and the earliest caecilian record for Gondwana, and forms the basis of a new genus, Rubricacaecilia.
Abstract: Of living amphibian groups, the limbless burrowing caecilians are amongst the most highly specialised, but are the least known. Their fossil record is extremely poor, leaving unresolved questions as to their origins, relationships and early distribution. We describe here caecilian remains from a Lower Cretaceous (Berriasian) microfossil locality near Anoual, Morocco. This material represents the second oldest record for the group, after the Jurassic Eocaecilia of North America, and the earliest caecilian record for Gondwana. It forms the basis of a new genus, Rubricacaecilia, which appears slightly more derived than Eocaecilia, but lacks major features of crown-group taxa. We support the use of Apoda Oppel, 1811 for the crown-group alone, and Gymnophiona Rafinesque 1814 for the clade comprising stem-group taxa + Apoda.
54 citations
TL;DR: Analysis of the disparity of these four clades shows that they are significantly less morphologically variable than the original polyphyletic taxon, demonstrating the possible effects of taxonomic error on macroevolutionary studies of morphological disparity.
Abstract: The paraphyletic trilobite suborder Ptychopariina includes a large proportion of Cambrian trilobite diversity and is probably ancestral to most groups of post-Cambrian trilobites. Resolution of the phylogenetic relationships within the group is therefore crucial to a better understanding of the initial radiation of trilobites. The recognition of approaches that can successfully resolve the relationships of ptychoparioid taxa is an important first step towards this aim. Cladistic analysis was used to determine relationships within the Cambrian ptychoparioid trilobite family Conocoryphidae, and to test claims that the family is polyphyletic. Ninety-seven characters were coded for 40 conocoryphid species and nine non-conocoryphids. The results indicate that the family consists of four distantly related clades. Three are recognized here as distinct families, including an extensively revised Conocoryphidae, and the families Holocephalidae and Atopidae. The fourth clade is referred to the subfamily Acontheinae (Corynexochida) as the new Tribe Hartshillini. Analysis of the disparity of these four clades shows that they are significantly less morphologically variable than the original polyphyletic taxon, demonstrating the possible effects of taxonomic error on macroevolutionary studies of morphological disparity.
42 citations
TL;DR: Three lungfish species are recognized from tooth plates recovered from shales of the Mut Formation (Qusseir Group) in eastern Dakhleh Oasis, and it is demonstrated that many tooth plates assigned to this species subsequent to its original description do not belong within C. humei.
Abstract: Three lungfish species are recognized from tooth plates recovered from shales of the Mut Formation (Qusseir Group) in eastern Dakhleh Oasis. Ceratodus humei Priem, 1914 is identified on characters shared with the type specimen, and Neoceratodus africanus Haug, 1905 on characters shared with the type specimen and specimens assigned to this species by subsequent authors. Protopterus crassidens sp. nov. is represented by two recently found plates, as well as two plates previously considered to represent Ceratodus or Protopterus humei. These plates all bear three ridges and crests, unusually heavy mesial ridges, crushing bollard-like buccal cusps to the mesial ridges and thick, robust buccal margins. The status and characteristics of C. humei are reviewed and the general problems of interspecific variation of fossil lungfish tooth plates and species recognition based on tooth plates are discussed. The diagnosis of C. humei is revised and the species returned to its original generic assignment, based mainly on the broad sample of tooth plates from Dakhleh Oasis. This sample demonstrates that many tooth plates assigned to this species subsequent to its original description do not belong within C. humei. New specimens of N. africanus are described from Bahariya Oasis.
TL;DR: In this paper, the authors investigated the distribution of calcified algae, cyanobacteria and associated Microproblematica in the Ordovician marine limestones in the northern Tarim Basin, Xinjiang.
Abstract: Boreholes between Kuqa and Korla, in the northern Tarim Basin, Xinjiang, penetrated Ordovician marine limestones at depths of 5–6.2km. From three boreholes 54 out of a total of 170 limestone samples contain calcified algae, cyanobacteria and associated Microproblematica. Calcified cyanobacteria (GirvanellaBotomaella, ?Subtifloria) account for 37 per cent of occurrences; green algae (Dasyporelleae and Vermiporella) 28 per cent; Microproblematica (NuiaBevocastriaRothpletzellaHalysis) 20 per cent; and ‘solenoporaceans’ 15 per cent GirvanellaNuia are common in the Early Ordovician deposits, and ‘solenoporaceans’ are abundant in the Mid-Ordovician. Dasyporelleae and Vermiporella are most abundant in Mid–Late Ordovician samples. Calcified cyanobacteria are common throughout the limestone succession, but particularly in the Mid Ordovician part. MoniliporellaContextaPlexaTexturata, and Villosoporella, hitherto placed in the supposed red algal family Moniliporellaceae Gnilovskaya, are here regarded as dasycladalean green algae. Despite some omissions, this Tarim flora broadly resembles others from Kazakhstan, Baltica and North America, indicating the generally cosmopolitan nature of Ordovician calcified algae and cyanobacteria.
TL;DR: It is concluded that Amphitherium probably had reached the grade of modern therians in the division between diphyodont premolars and monophyodont molars, and probably was secondarily increased in the number of molars.
Abstract: Four fragmentary mandibles from the Stonesfield Slate facies, Taynton Limestone Formation, Middle Bathonian (Middle Jurassic), England, represent two species of AmphitheriumA prevostiiA rixoni sp nov Both species had five lower premolariform teeth The composite formula for the lower dentition of Amphitherium appears to have been I/4, C/1, P/5, M/6–7 The seventh molar is not present in the presumably oldest individual, and its presence is regarded as probably an individual variation The mosaic evolution of patterns of differentiation of the postcanine dentition from nonmammalian cynodonts to modern therian mammals is reviewed It is concluded that Amphitherium probably had reached the grade of modern therians in the division between diphyodont premolars and monophyodont molars The common ancestor of Amphitherium and zatheres probably had lost the primitive pattern of posterior shift of the postcanine dentition, which appears to have consisted of five premolars and four or possibly five molars In Amphitherium the number of molars probably was secondarily increased
TL;DR: Parsimony analysis of partitioned datasets indicates that more phylogenetic information can be recovered from S rather than P or M element positions, although data from all three positional groups are preferable to data from just one.
Abstract: A numerical cladistic analysis of the conodont family Palmatolepidae has been undertaken to determine the applicability of the technique to group-wide systematic revision. Results suggest a new hypothesis of relationships that is considerably more parsimonious than trees compatible with existing hypotheses of relationships, or trees that are even loosely constrained stratigraphically. This may occur either because the fossil record is incomplete, because taxon sampling for the cladistic analysis is low, or because the most parsimonious trees approximate the true tree less well than do stratigraphically-constrained trees (or because of a combination of these factors). Although more taxa and more characters would be preferable in choosing between these possibilities, the tree derived solely from morphological data is adopted. Thus, stratigraphic data can be used to test hypotheses of relationships and construct phylogenies; hypotheses of relationships can be used to test the completeness of the conodont fossil record. Existing schemes of classification within the Palmatolepidae are rejected because most groups within them are either polyphyletic or paraphyletic. A new scheme is presented. Character changes suggest correlated, progressive and mosaic evolution within the Palmatolepidae. Parsimony analysis of partitioned datasets indicates that more phylogenetic information can be recovered from S rather than P or M element positions, although data from all three positional groups are preferable to data from just one. Thus, multielement taxonomy is essential to the resolution of conodont interrelationships.
TL;DR: Priohybodus cf. arambourgi is reported from the Tacuarembo Formation of Uruguay as mentioned in this paper, where 22 isolated teeth and a dorsal fin spine were found in a thin bone bed associated with abundant bone fragments, scales and teeth of semionotiform fishes and theropod dinosaurs.
Abstract: Priohybodus cf. P. arambourgi is reported for the first time from the Tacuarembo Formation of Uruguay. This species is a hybodontid shark known previously only from Upper Jurassic and Lower Cretaceous deposits of Saharan Africa and the Arabian Peninsula. The material (22 isolated teeth and a dorsal fin spine) was found in a thin bone bed, associated with abundant bone fragments, scales and teeth of semionotiform fishes and theropod dinosaurs. Until now, the age of the Tacuarembo Formation has been difficult to determine because its fossil content lacked useful biostratigraphic indicators. The finding of Priohybodus cf. P. arambourgi in that unit greatly expands the palaeobiogeographic range of the species, and allows us to propose a Late Jurassic–Early Cretaceous age for the Tacuarembo Formation.
TL;DR: In this article, the authors reported the first occurrence of permineralized plant fossils in volcaniclastic lithologies from China and in doing so describe a new species of cardiocarpalean ovule within tuffaceous sediments from a recently discovered locality near Pingquan, Hebei Province.
Abstract: In this paper we report the first occurrence of permineralized plant fossils in volcaniclastic lithologies from China and in doing so describe a new species of cardiocarpalean ovule permineralized within tuffaceous sediments from a recently discovered locality near Pingquan, Hebei Province, North China. The tuff is part of the Early Permian Taiyuan Formation which contains a diverse fossil plant assemblage that includes cordaitean spermatophytes, lepidodendralean lycophytes, equisetophytes, and filicalean ferns, all of which were typical of Permian floras of northern China at this time. Specimens of Cardiocarpusdabiziae sp. nov. have the characteristic platyspermic shape and vascularization of cardiocarpalean ovules, and display prominent protuberances on the exterior of the integument. The integument of the ovule is composed of three layers; a thick sarcotesta, a thin and comparatively dense sclerotesta, and a single layer of large endotesta cells. The pollen chamber produces a slender nucellar beak. In several specimens the megaspore membrane contains well-developed tissue of the megagametophyte. The ovules have prominent external integumentary protuberances which suggest that well-developed systems of plant/animal interactions were operative in Early Permian wetland biotas of the Cathaysian realm.
TL;DR: Benthic foraminifera are described for the first time from the Gibraltar Limestone Formation of the Rock of Gibraltar as mentioned in this paper, and are consistent with an Early Jurassic (Sinemurian) age for the upper part of the &62;460m-thick Gibraltar limestone.
Abstract: Benthic foraminifera are described for the first time from the Gibraltar Limestone Formation of the Rock of Gibraltar. The new species Siphovalvulina colomiS. gibraltarensisRiyadhella praeregularis occur with Duotaxis metula Kristan, Everticyclammina praevirguliana Fugagnoli, Siphovalvulina sp.,an atypically early example of Textulariopsis sp., and Nodosaria sp. Microflora are present as the probable cyanobacterium Cayeuxia ?piae Frollo, the alga Palaeodasycladus ?mediterraneus (Pia), and the disputed alga Thaumatoporella ?parvovesiculifera (Raineri). The foraminifera compare most closely with poorly-known taxa from Italy, Spain and Morocco, and are consistent with an Early Jurassic (Sinemurian) age for the upper part of the &62;460-m-thick Gibraltar Limestone. Most are textulariids and more primitive than species well known from the later Early Jurassic (Pliensbachian) of the Mediterranean region, especially Morocco and Italy. The biota as a whole is characteristic of inner carbonate platform environments widespread along the rifted western margins of the Early Jurassic Tethys, notably those recorded from Morocco, Italy and Greece as well as southern Spain.
TL;DR: More than 4200 kg of limestone, representing 980 productive samples, from the upper Middle and lower Upper Cambrian interval as it is developed at two, apparently stratigraphically continuous, key sections are studied in this paper.
Abstract: More than 4200 kg of limestone, representing 980 productive samples, from the upper Middle Cambrian, Upper Cambrian, and lowermost Ordovician in western and north-western Hunan were processed for paraconodonts, protoconodonts, and euconodonts. The focus of the present paper is on the upper Middle and lower Upper Cambrian interval as it is developed at two, apparently stratigraphically continuous, key sections. The collections studied, which include more than 20,000 specimens and are quite diverse taxonomically, prove that some protoconodonts and paraconodonts are useful biostratigraphically. Previously proposed protoconodont-paraconodont biozones in Hunan are revised and correlated with recently revised trilobite biozones, as well as with protoconodont-paraconodont and trilobite biozones in North China. Twenty-six species and seven conditionally identified species belonging to 13 genera are described. Among these, two genera (Huayuanodontus and Yongshunella) and two species (Westergaardodina elegans and Yongshunella polymorpha) are new. This study has special interest for Cambrian biostratigraphy because the two studied sections are global stratotype candidates for the Middle-Upper Cambrian series boundary. The level of the Upper-Middle Cambrian Series boundary, as currently recognized in China (at the base of the Linguagnostus reconditus Trilobite Biozone) is well marked in the paraconodont succession and can be traced into the Swedish standard succession using these fossils. By contrast, another level recently proposed as a potential global Middle-Upper Cambrian Series boundary level, the base of the Glyptagnostus reticulatus Trilobite Biozone, does not coincide with any marked change in the Hunan conodont species succession useful for local and regional correlation.
TL;DR: In this article, four new genera and species of arthropod, Cambronatus brasseli, Wingertshellicus backesiEschenbachiellus wuttkensis and Magnoculus blindi, are described from the Hunsruck Slate (Lower Emsian) of Germany.
Abstract: Four new genera and species of arthropod, Cambronatus brasseliWingertshellicus backesiEschenbachiellus wuttkensis and Magnoculus blindi, are described from the Hunsru¨ck Slate (Lower Emsian) of Germany All four occur in the Wingertshell Member in the vicinity of Bundenbach They preserve remarkable details of the ventral morphology, including the appendages, as a result of pyritization In each case the body consists of just two tagmata, a cephalon and a large number of similar trunk somites Both CambronatusWingertshellicus have fluke-like appendages making up a tail fan The affinities of these arthropods lie with the Crustacea, apart from Magnoculus, which is an arachnomorph, but they do not fall within those clades with modern representatives They show that morphologies other than those represented by trilobites and modern arthropod groups persisted long after the Cambrian, at least in muddy bottom marine settings
TL;DR: The crinoids and blastoids from the Pilton (Beds) Formation of the type Devonian of north Devonshire are revised in this paper, showing that the majority of these fossils are Famennian, although three specimens from Fremington are probably Early Carboniferous (Tournaisian).
Abstract: The crinoids and blastoids from the Pilton (Beds) Formation of the type Devonian of north Devonshire are revised. These fossils were monographed by the Rev. G. F. Whidborne in 1898, but have not been studied since that time. Recent studies on various groups of fossils from the Pilton and related rocks in North Devon confirm that the great majority of these fossils are Famennian, although three specimens from Fremington are probably Early Carboniferous (Tournaisian). We identify four blastoid taxa from a fauna that is sparse and poorly preserved; two spiraculates, one fissiculate, and one taxon unidentifiable at the ordinal level. Mesoblastus cf. M. crenulatus from the Gattendorfia Zone (Lower Carboniferous) near Fremington is the oldest known representative of this genus. The crinoid fauna is somewhat more diverse, but the preservation is equally poor. No changes are made in the flexible crinoids. Among camerate crinoids, one species is reassigned to Eumorphocrinus and one is retained in Actinocrinites. Specimens of some crinoids, such as Rhodocrinites and Megistocrinus, are so poorly preserved that certain identification was not possible. The hexacrinoid Adelocrinus, relegated to uncertainty for 150 years, is here shown to be a valid genus that is very similar to Arthroacantha, but not synonymous with it. Among the cladid crinoids, the dominant groups are those within the Superfamily Scytalocrinacea, which includes Bridgerocrinus, Sostronocrinus, and Scytalocrinus, all of which are placed in the new family Sostronocrinidae. One new species, Glossocrinus whidbornei, is named. Non-pinnulate cladids, common in older Devonian rocks, do not occur. The fauna shows considerable similarity with faunas from eastern North America and Germany. It shows less resemblance to the extensive Famennian crinoid and blastoid fauna of north-western China, despite some remarkable congruencies, especially the occurrence of very similar species of Actinocrinites in these widely separated areas.
TL;DR: In this paper, an elaboration of a little known technique involving the use of polarised light sources, together with a polarising filter over the camera lens, is described and used to demonstrate its usefulness in the photography of low contrast fossils.
Abstract: An elaboration of a little known technique involving the use of polarised light sources, together with a polarising filter over the camera lens is described and used to demonstrate its usefulness in the photography of low contrast fossils.
TL;DR: The apparent presence of two pairs of antennae constitutes the first available morphological evidence for a close relationship between this species and, by association, all thylacocephalans, and the Crustacea.
Abstract: A continuing study of a collection of marine arthropods from the Upper Cretaceous of Sahel Alma in Lebanon has uncovered a new genus and species of the problematic arthropod group Thylacocephala. The apparent presence of two pairs of antennae constitutes the first available morphological evidence for a close relationship between this species and, by association, all thylacocephalans, and the Crustacea.
TL;DR: The investigated fauna contains the youngest astylospongiids known and the oldest well‐preserved, and most diversified Palaeozoic hexactinosans.
Abstract: The rich fauna of Late Devonian (Late Frasnian) siliceous sponges from the Holy Cross Mountains, Poland is composed of 15 species and 11 genera. Both astylospongid demosponges (lithistids) and hexactinosan hexactinellids are present. The following new genera and/or species are proposed: D regulara Rigby and Pisera sp. nov., Jazwicella media Rigby and Pisera gen. et sp. nov., Astyloscyphia irregularia Rigby and Pisera gen. et sp. nov., A. turbinata Rigby and Pisera gen. et sp. nov., Astylotuba modica Rigby and Pisera gen. et sp. nov., Paleoregulara cupula Rigby and Pisera gen. et sp. nov., Paleoramospongia bifurcata Rigby and Pisera gen. et sp. nov., Cordiospongia conica Rigby and Pisera gen. et sp. nov., Paleocraticularia elongata Rigby and Pisera gen. et sp. nov., P gigantia Rigby and Pisera gen. et sp. nov., Polonospongiadevonica Rigby and Pisera gen. et sp. nov., P fistulata Rigby and Pisera gen. et sp. nov., Urnospongia modica Rigby and Pisera gen. et sp. nov., and Conicospongia annulata Rigby and Pisera gen. et sp. nov. The investigated fauna contains the youngest astylospongiids known and the oldest well-preserved, and most diversified Palaeozoic hexactinosans. The sponge fauna constituted a significant element of a brachiopod-coral-sponge assemblage that inhabited a deep slope of the local Dyminy Reef structure, during its final phase of growth, in a clearly hemipelagic setting. This fauna is limited to the intrashelf depression within an incipiently drowned carbonate platform.
TL;DR: It is suggested that Eremopezus represents an endemic African group that independently attained large size and flightlessness and is linked to any known ratite lineage, to the Phorusrhacoidea, or to the extinct predatory birds of the Eocene.
Abstract: Eremopezus eocaenus Andrews, 1904 is a giant groundbird from upper Eocene deposits of the Fayum, Egypt, which has hitherto been known from non-diagnostic fragmentary material. New fossils collected from quarry L-41 of the Jebel Qatrani Formation include two well-preserved distal tarsometatarsi and an associated whole tarsometatarsus and distal tibiotarsus that allow a more precise evaluation of the phylogenetic position and tarsal function of Eremopezus. Unlike most ratites, the distal tarsometatarsus has a patent distal foramen and a slight hallucal digit. The trochlea for digits II and IV are only slightly reduced in size, are splayed to the right, and the heads lack deep grooving. These features resemble the condition seen in BalaenicepsSagittarius, suggesting active use of the toes in grasping or manipulation, rather than the condition in graviports and cursors, which have reduced medial and lateral trochleae often with distinct grooving of the heads. The limb is relatively long and gracile, another difference from graviports. There is no compelling evidence to link Eremopezus to any known ratite lineage, to the Phorusrhacoidea, or to the extinct predatory birds of the Eocene (e.g. Diatryma, Gastornis). We suggest that Eremopezus represents an endemic African group that independently attained large size and flightlessness.
TL;DR: In this article, a succession of 38 upper Llandovery-lower Wenlock chitinozoan taxa from graptolitic horizons in the Banwy River section (Powys, Wales) is described.
Abstract: The succession of 38 upper Llandovery–lower Wenlock chitinozoan taxa from graptolitic horizons in the Banwy River section (Powys, Wales) is described. Five new species are named: Bursachitina nestoraeConochitina leviscapulaeConochitina mathrafalensisBelonechitina caveiBelonechitina meifodensis. A further ten taxa are described under open nomenclature. Seven chitinozoan biozones are recognized in the Banwy River section, three of which (Cingulochitina bouniensisConochitina acuminataSalopochitina bella) are new. The base of each biozone is correlated with the graptolite biostratigraphical scheme as follows: Angochitina longicollis Biozone — upper spiralis Biozone; Conochitina acuminata Biozone — lowermost lapworthi Biozone; Margachitina banwyensis Biozone — upper lapworthi Biozone; Margachitina margaritana Biozone — lowermost insectus Biozone; Cingulochitina bouniensis Biozone — upper murchisoni Biozone; Salopochitina bella Biozone — upper firmus Biozone. The succession of chitinozoan biozones in the Banwy River section is compared with that in other sections which have graptolite biostratigraphical control. This has highlighted the following: (1) the correlation of the base of the dolioliformis Biozone with the graptolite biozonation is imprecise; (2) E. dolioliformis is recorded only from levels after the first A. longicollis in Sweden (although this may reflect previously unrecognized synonymies); (3) the longicollis Biozone may be diachronous, its base correlating with levels low in the Telychian in Sweden, Norway and Estonia and with the upper Telychian spiralis Biozone in Wales and the Prague Basin; (4) data herein and from the Prague Basin indicate that the base of the margaritana Biozone correlates with a level low in the insectus Biozone.
TL;DR: These are the first fossil records of Trachelas, Enacrosoma and Pseudosparianthis, giving them stratigraphic ranges of 15–20 my; the genera Anelosimus, Cyclosa and Agyneta are unknown in the fossil record.
Abstract: Trachelas poinari sp. nov. (Corinnidae), Miagrammopes sp. indet. (Uloboridae) and the first indisputable fossil Lycosidae (gen. et sp. indet.) are newly identified and described in Miocene amber from the Dominican Republic. The following are junior synonyms: Nops segmentatus Wunderlich, 1988 of N. lobatus Wunderlich, 1988 (Caponiidae); Azilia muellenmeisteri Wunderlich, 1988 of A. hispaniolensis Wunderlich, 1988 (Tetragnathidae); and Lyssomanes galianoae Reiskind, 1989 of L. pristinus Wunderlich, 1986 (Salticidae). The specimens described as Nops sp. (Caponiidae), Selenops beynai Schawaller, 1984, S. sp. 1, and S. sp. 2 (Selenopidae) by Wunderlich (1988) are unrecognizable as distinct species. The following new combinations are presented: gen. indet. clypeatus (Wunderlich, 1988) (=Anelosimus clypeatus) (Theridiidae); Meioneta bigibber (Wunderlich, 1988) (=Agyneta bigibber), M.fastigata (Wunderlich, 1988) (=Agyneta fastigata), M. separata (Wunderlich, 1988) (=Agyneta separata) (Linyphiidae); Enacrosoma verrucosa (Wunderlich, 1988) (=Cyclosa verrucosa) (Araneidae); Pseudosparianthis pfeiferi (Wunderlich, 1988) (=Tentabunda pfeiferi) (Sparassidae). Theridion wunderlichi nom. nov. is proposed as a replacement name for T. ovale Wunderlich, 1988 (nom. preocc.). The previously unknown male of Styposis pholcoides Wunderlich, 1988 (Theridiidae) is described. Additional features of Argyrodes crassipatellaris Wunderlich, 1988 (Theridiidae) are described; this species is transferred from the trigonum to the cancellatus species group. Nine specimens belonging to six previously described species, and six juvenile Selenops sp. (including one exuvium) are newly identified. These are the first fossil records of Trachelas, Enacrosoma and Pseudosparianthis, giving them stratigraphic ranges of 15–20 my; the genera Anelosimus, Cyclosa and Agyneta are unknown in the fossil record.
TL;DR: Achanarella trewini as mentioned in this paper is a torpedo-shaped jawless vertebrate with a strongly hypocercal tail and well-developed anal fin, which has at least 13 branchial openings with possibly more than 20.
Abstract: A new jawless vertebrate, Achanarella trewini gen. et sp. nov., is described from some recently discovered, relatively well–preserved specimens from the Achanarras fish bed at Achanarras Quarry, northern Scotland. The Achanarras fish bed is of Middle Devonian (Eifelian) age. Achanarella is a torpedo–shaped jawless vertebrate with a strongly hypocercal tail and well–developed anal fin. It has at least 13 branchial openings with possibly more than 20. It is scaleless. Achanarella compares well with the Frasnian Euphaneropidae of the Escuminac Formation in Quebec, Canada, and Cornovichthys blaauweni Newman and Trewin, 2001, also from the Achanarras fish bed. It differs from these forms mainly in being extremely long and thin and having a very small head compared with body length.
TL;DR: A small brachiopod fauna is described from the carbonate rocks of the basal Shazipo Formation of the Baoshan Block, western Yunnan, south-west China, including significant new ventral and dorsal internal morphological features of Cryptospirifer omeishanensis Huang as discussed by the authors.
Abstract: A small brachiopod fauna is described from the carbonate rocks of the basal Shazipo Formation of the Baoshan Block, western Yunnan, south-west China, including significant new ventral and dorsal internal morphological features of Cryptospirifer omeishanensis Huang. This fauna is regarded as Wordian (Middle Guadalupian, Middle Permian) because of the presence of Cryptospirifer omeishanensis Huang and associated fusulinids (Neoschwagerina craticulifera Zone). Palaeobiogeographically, the brachiopod fauna is of considerable interest because of its admixed nature characterized by typical warm-water Cathaysian elements intermingled with temperate Peri-Gondwanan taxa. This in turn is interpreted to indicate that the Baoshan Block may have been situated in an intermediate palaeogeographical position between Gondwanaland to the south and Cathaysia to the north during the Mid Permian and, as such, it probably furnished an important ‘stepping stone’ for the dispersal of Mid Permian eastern Tethyan marine invertebrate taxa (e.g. Cryptospirifer) to the western Tethys.
TL;DR: The brachiopods described herein from Hamakhtesh Hagadol comprise a fauna located at the northernmost part of the Indo‐African Faunal Realm within the Jurassic Ethiopian Province.
Abstract: The Callovian Zohar and Matmor formations in the Negev, southern Israel, consisting of marls, shales and limestones, have yielded 13 brachiopod species (2 rhynchonellids, 11 terebratulids), referred to 12 genera, of which one genus and five species are new: Apatecosia inornata, Bihenithyris mediocostata, Digonella boylani sp. nov., Dissoria bretti sp. nov., Burmirhynchia jirbaensis, Kutchithyris landeri sp. nov., Pleuraloma triangulatum, Polyplectella debriani gen. et sp. nov., Ptyctothyris daghaniensis, Somalirhynchia africana, Striithyris saudiarabica, S. telemi sp. nov., and Zeilleria sp. The brachiopods described herein from Hamakhtesh Hagadol (Kurnub Anticline) comprise a fauna located at the northernmost part of the Indo-African Faunal Realm within the Jurassic Ethiopian Province.
TL;DR: The first Mesozoic centipede was described by as mentioned in this paper from the Lower Cretaceous (Aptian) Crato Formation of north-east Brazil, which is known from Dominican and Baltic amber, the Carboniferous (Westphalian D) Francis Creek Shale of Mazon Creek, Illinois, and the Silurian and Devonian of Britain.
Abstract: The first Mesozoic scutigeromorph centipede (Myriapoda: Chilopoda), Fulmenocursor tenax gen. et sp. nov., is described from the Lower Cretaceous (Aptian) Crato Formation of north-east Brazil. Previously described fossil Scutigeromorpha are known from Dominican and Baltic amber, the Carboniferous (Westphalian D) Francis Creek Shale of Mazon Creek, Illinois, the Silurian and Devonian of Britain, and the Devonian of New York State.