Palaeobiogeography of the Ordovician trilobite Prosopiscus,with a new species from western New South Wales

Prosopiscus is particularly important in Ordovician palaeobiogeography because of its wide geographic distribution in Gondwana and peri-Gondwanan regions. It appears to have been confined to low palaeolatitudes, representing a characteristic member of the warm water eastern Gondwanan shelf faunas. Trends in the distribution of the Ordovician genus can be observed due to its long stratigraphic range. Prosopiscus was restricted to, and may have originated in, Australia during the late Early Ordovician (Bendigonian-Chewtonian). By the Middle Ordovician (Darriwilian), Prosopiscus had dispersed to other parts of Gondwana and peri-Gondwana, including the North and South China blocks, Tarim, central Himalayas, and the Argentine Precordillera (South America). Possible explanations for the distribution of Prosopiscus are that: (1) there were no oceanic barriers preventing dispersal of trilobites between different regions of Gondwana, thus permitting uninhibited migration over vast distances; (2) Prosopiscus was not restricted to a specific biofacies; (3) a major eustatic transgression during the early Darriwilian may have facilitated the dispersal of Prosopiscus in allowing further development and expansion of marine environments; and (4) a prolonged planktonic larval stage may have permitted wide dispersal.

Prosopiscus lauriei sp. nov. is described from the late Early Ordovician (Bendigonian-Chewtonian) Tabita Formation at Mount Arrowsmith, northwestern New South Wales, Australia. The new species is closely related to P. praecox, from the Nora Formation, Georgina Basin, central Australia, and to P. magicus from northwest China.     

Possible fossil impression in sandstone from the late Palaeoproterozoic-early Mesoproterozoic Semri Group (lower Vindhyan Supergroup), central India

The Lower–Middle Ordovician Zitai Formation of the South China palaeoplate consists of a succession of purple red, nodular argillaceous limestones. Palaeogeographically, it is distributed along the southeastern margin of the Yangtze Platform, and is of late Floian to Dapingian age, correlative with the Dawan Formation of the Middle and Lower Yangtze Platform. In Shitai County, Anhui Province, East China, the Zitai Formation is rich in conodonts, enabling the recognition of four biozones based on first appearance data. Detailed palaeontological and biostratigraphical study of these conodonts reveals that the Ordovician conodont radiation in the Lower Yangtze Platform attained its first diversity peak low in the Oepikodus evae Biozone. This diversification is generally consistent with macroevolutionary trends of brachiopods of South China and graptolites of the Upper Yangtze Platform, but was earlier than that of trilobites and acritarchs of the same palaeoplate. Correlation with the sea-level curve for South China suggests that conodont diversity change during the Ordovician radiation was mainly controlled by regional sea-level fluctuations.     

Early Carboniferous Bivalvia from western Argentina

González, C. R., Early carboniferous Bivalvia from western Argentina. Alcheringa 18, 169–185. ISSN 0311-5518.

Lower Carboniferous deposits of western Argentina yield invertebrates and plant remains. In the Tournaisian epoch, a transgression from the ‘Pacific’ flooded the Rio Blanco Basin, forming a semi-restricted inland sea. Marine invertebrates of this age comprise the Malimanian fauna, which is based on the Protocanites-Rossirhynchus Assemblage. Eleven species of Bivalvia are here described Palaeoneilo subquadratum sp. nov., Malimania triangularis gen. et sp. nov., Phestia sp., Volsellina? sp. Posidoniella malimanensis sp. nov., Leptodesma? sp., Schizodus sp., Cypricardinia? sp., Edmondia? sp., Sanguinolites punillanus sp. nov., and Vacunella? sp. nov. They are accompanied by gastropods, trilobites, conularids and corals. The Malimanian fauna is regarded as a poorly to moderately varied assemblage that was influenced by some basinal restrictions. It was probably connected to faunas of Chile and Peru, and lived during a stage of mild climate before the beginning of the Late Palaeozoic ice age.     

New,early ostracods from the Ordovician (Tremadocian) of Iran: systematic,biogeographical and palaeoecological significance

New Tremadocian ostracod material from the Alborz Mountains of Iran confirms the early and widespread occurrence of the Ordovician genus Nanopsis, and the apparently simultaneous first appearance of ostracods in the fossil record at the level of the P. deltifer conodont biozone (485.5 Ma) from China to Argentina. Nanopsis pairidaeza sp. nov. adds to the pool of species diversity for the Early Ordovician, though documented Tremadocian ostracod generic diversity remains low, with only four genera. The presence of Early Ordovician ostracods in Alborz, their occurrence elsewhere in palaeocontinental Gondwana, Baltica and China coupled to their marked absence from the Tremadocian of Laurentia and Siberia, supports the notion of the earliest occurrence of ostracods centred on Gondwana/Baltica.     

Trilobites from the Middle Ordovician Stairway Sandstone,Amadeus Basin,central Australia

Abstract

During the Middle Ordovician (Darriwilian) sandstones and siltstones were deposited in the epicontinental Larapintine Sea, which covered large parts of central Australia. The Darriwilian Stairway Sandstone has, for the first time, been sampled stratigraphically for macrofossils to track marine benthic biodiversity in this clastic-dominated shallow-water palaeoenvironment situated along the margin of northeastern Gondwana. The faunas from the Stairway Sandstone are generally of low diversity and dominated by bivalves but include several animal groups, with trilobites representing 25% of the entire shelly fauna. Thirteen trilobite taxa are described from the Stairway Sandstone; the fauna displays a high degree of endemism. One new species, Basilicus (Parabasilicus) brumbyensis sp. nov. is described.     

A new Ordovician rostroconch mollusc from Kazakhstan

The rostroconch mollusc Eopteria aiteneria sp. nov. is described from the Late Ordovician Angrensor Formation of north-eastern Central Kazakhstan; it is the first and only known representative of this group from the Ordovician of central Asia. By the beginning of the Late Ordovician Eopteria and the family Eopteriidae were on the verge of extinction and the new Kazakhstan species represents the youngest preserved record of the family in the Ordovician. It is likely that the group found a refuge in the diverse, but rather conservative, faunal assemblage of the Hiberno-Salairian type associated with Late Ordovician carbonate algal build-ups and mud mounds which spread widely during the late Caradoc to mid Ashgill across Kazakhstanian volcanic island arcs and microplates.     

Early Miocene bivalves from the Cape Melville Formation,King George Island,West Antarctica

Seven species of marine bivalves, including six new taxa, are described from the Cape early Miocene Melville Formation which crops out on the Melville Peninsula, King George Island, West Antarctica. The bivalve assemblage includes representatives of the families Nuculidae, Ennucula frigida sp. nov., E. musculosa sp. nov.; Malletidae, Neilo (Neilo) rongelii sp. nov.; Sareptidae, Yoldia peninsularis sp. nov.; Limopsidae, Limopsis psimolis sp. nov.; Hiatellidae, Panopea (Panopea) sp. cf. P. regularis; and Pholadomyoida (Periploma acuta sp. nov.). Species studied come from four sedimentary sections measured in the upper part of the unit. Detailed morphologic features of nucloid and arcoid species are exceptionally well preserved and allow for the first time reconstruction of muscle insertions as well as dentition patterns of Cenozoic taxa. Known geological distribution of the species is in agreement with the early Miocene age assigned to the Cape Melville Formation. The bivalve fauna from Cape Melville Formation is the best known from Antarctic Miocene rocks, a time of complex geologic, paleogeographic and paleoclimatic changes in the continent. The new fauna introduces new taxonomic and palaeogeographic data that bear on the question of opening of sea gateways and distribution of Cenozoic biota around Antarctica.     

Middle Ordovician (early Dapingian) conodonts in the Central Andean Basin of NW Argentina

Carlorosi, J., Heredia, S. & Aceñolaza, G, 2013. Middle Ordovician (early Dapingian) conodonts in the Central Andean Basin of NW Argentina. Alcheringa 37, 1–13. ISSN 0311-5518.

This paper describes and analyzes the significance of a conodont fauna from the Alto del Cóndor Formation, exposed in the Los Colorados region of the Argentine Eastern Cordillera. Identified taxa are Baltoniodus triangularis, Baltoniodus sp. cf. B. triangularis, Drepanodus sp., Drepanoistodus basiovalis, Drepanoistodus sp. B., Erraticodon patu, Gothodus costulatus, Oistodus sp., Trapezognathus diprion, T. quadrangulum, Triangulodus sp. and Triangulodus? sp. The presence of Baltoniodus triangularis indicates the base of the Dapingian stage (Middle Ordovician). In addition, we report the coexistence of T. diprion and T. quadrangulum. The conodont association suggests a faunal affinity with Baltica and South China, both belonging to the Shallow-Sea Realm of the Temperate-Cold Domain.

Josefina Carlorosi [josefinacarlorosi77@gmail]com], INSUGEO—Universidad Nacional de Tucumán—CONICET, Miguel Lillo 205, (4000) Tucumán, Argentina; Guillermo F. Aceñolaza [acecha@webmail.unt.edu.ar], Universidad Nacional de Tucumán—CONICET, Miguel Lillo 205, (4000) Tucumán, Argentina; Susana Heredia [sheredia@unsj.edu.ar], CONICET–CIGEOBIO and Instituto de Investigaciones Mineras, Facultad de Ingeniería, Universidad Nacional de San Juan, Urquiza y Libertador, (5400) San Juan, Argentina. Received 22.8.2012; revised 18.10.2012; accepted 24.10.12.     

New corystosperm ovulate fructifications from the Middle Triassic of eastern Australia

The genus Umkomasia Thomas is emended to include the corystosperm ovulate inflorescent genera Pilophorosperma Thomas and Karibacarpon Lacey. Three new species of large inflorescences are described and illustrated: Umkomasia polycarpa sp. nov. from the Esk Formation of Queensland and U. distans sp. nov. and U. sessilis sp. nov. from the Basin Creek Formation of New South Wales.     

Biostratigraphic potential of Middle Cambrian hyoliths from the eastern Georgina Basin

Fourteen hyolith taxa are documented from the Middle Cambrian (Templetonian to Floran) of the eastern (Queensland) portion of the Georgina Basin, Australia, as a contribution toward a prospective Australian Cambrian hyolith biozonation. The described fauna is from the Beetle Creek Formation (including Monastery Creek Phosphorite Member) and Gowers Formation. Additionally, the enigmatic Cupittheca and some indeterminate hyoliths are figured to illustrate aspects of hyolith morphology. Guduguwan hardmani, widespread in Ordian-early Templetonian strata of northern Australia, is here recorded from the early Templetonian of the eastern Georgina Basin. A new family Gakidae is established for sulcavitide hyolithomorphs with a conch of pentagonally tabernacular transverse section, to include Gaka, Kalkatungu gen. nov. and possibly Dorsolinevitus. New genera are the hyolithid Yalarrnga mara gen. et sp. nov., sulcavitid Kulangarra kutjurru gen. et sp. nov., gakid Kalkatungu murlu gen. et sp. nov. and angusticornid Yuku tjurtu gen. et sp. nov.; new species are Loculitheca kunka sp. nov., Carinolithes tjikilirri sp. nov., ?Sololites kankari sp. nov., ?Shandongolithes thakal sp. nov., ?Gerkella thuka sp. nov. and ?Yacutolituus rakatju sp. nov. Taxa in open nomenclature are Foersteotheca cf. dubecensis, ?Holmitheca sp. and ?Dorsojugatus sp. On present knowledge, the potential for an Australian Cambrian hyolith biozonation is limited in the Early Cambrian, but for the Middle Cambrian, G. hardmani is a widespread Ordian-early Templetonian indicator, while hyolith distribution in the Monastery Creek Phosphorite Member suggests a faunal turnover at or about the incoming of Acidusus atavus which may provide a basis for biozonation in the Floran stage.     

Late Carboniferous marine invertebrate zones of eastern Australia

Brachiopods of the Marginirugus barringtonensis and Levispustula levis Zones comprise the youngest of three major Carboniferous biostratigraphic units in eastern Australia. The remarkable change in the composition of marine invertebrates between the second and third of these units, a transition that only two brachiopod species are known to survive, has been attributed to the isolation of eastern Australia and to a drop in temperature. The Marginirugus barringtonensis and Levipustula levis Zones are redefined from reference sections in the Myall region, N.S.W.; the L. levis Zone now includes the Syringothyris bifida Zone of Campbell (1961). Faunal sequences show that these two zones are closely related and that there is no hiatus between them, as formerly proposed by McKellar (1965). Conodonts identified by Mr. D. Crane indicate a late Viséan to early Namurian age for the Marginirugus barringtonensis Zone, and an age of early Namurian for the base of the Levipustula levis Zone; brachiopod evidence indicates that the L. levis Zone extends into the Westphalian. The younger Auriculispina levis Zone from the Yarrol Basin may be coeval with the Trigonotreta campbelli Zone from N.S.W. Faunas from both the L. levis and A. levis Zones are present in Argentina and many species from the L. levis Zone have affinities with forms from the Baikal region, U.S.S.R. Correlations based on the zones have eliminated the need for a hiatus between the Branch Creek and Baywulla Formations in the Yarrol Basin.

Taxa described from the Marginirugus barringtonensis and Levipustula levis Zones in the Myall region include Yagonia gibberensis Roberts gen. et sp. nov., Bulahdelia myallensis Roberts gen. et sp. nov., Alispirifer yagonensis Thompson sp. nov., A. alatus Thompson sp. nov., Licharewia bootiensis Thompson sp. nov., Spirifer pristinus (Maxwell), Spiriferi sp., Neospirifer campbelli Maxwell and N. senilis Maxwell.     

First soft-bodied fossil from the Ordovician of Peru

Konservat-Lagerstätten are a source of insurmountable information on the diversity of fossil assemblages during the lower Palaeozoic. Soft-bodied fossils are especially rare in South America, but a new locality has been discovered from the Middle Ordovician of Peru that has produced the fairly well-preserved possible palaeoscolecidan Juninscolex ingemmetianum gen. et sp. nov. The distinctive characteristics of this worm make it similar to European taxa within the group.     

Gracilitheca and Nephrotheca (Hyolitha,Orthothecida) in the Cambrian of the Barrandian area,Czech Republic

VALENT, M., FATKA, O. & MAREK, L., iFirst article. Gracilitheca and Nephrotheca (Hyolitha, Orthothecida) in the Cambrian of the Barrandian area, Czech Republic. Alcheringa, 1–10. ISSN 0311-5518.

Five orthothecid hyoliths, Gracilitheca mirabilis sp. nov., Gracilitheca triangularis sp. nov., Gracilitheca sp., Nephrotheca betula sp. nov. and Nephrotheca sp. are described from the ‘middle’ Cambrian Buchava Formation of the Skryje–Tý?ovice Basin in the Czech Republic. The new forms are based on about forty well-preserved external and internal moulds of conchs; opercula of all species remain unknown. Stratigraphic ranges and geographic distributions within the Skryje Tý?ovice Basin are established for all taxa.     

Carboniferous and Permian Rugosochonetidae (Brachiopoda) from West Spitsbergen

The rugosochonetid brachiopod species Lissochonetes geinitzianus from the Kazimovian of the Nordenskioldbreen Formation, and Dyoros (Dyoros) mucronata sp. nov., Dyoros (Dyoros) spitzbergianus and Lissochonetes superba from the Artinskian to latest Permian Kapp Starostin Formation in West Spitsbergen are described and figured. Dyoros is generally restricted to the Boreal Realm, whereas Lissochonetes is mostly distributed in the Boreal Realm, but occasionally present in the Palaeoequatorial and Gondwanan Realms.     

A new crustacean clam shrimp (Spinicaudata: Eosestheriidae) from the Upper Triassic of Argentina and its importance for ‘conchostracan’ taxonomy

A new species of a fossil crustacean clam shrimp (Spinicaudata: Eosestheriidae) Menucoestheria wichmanni is described from the lower Upper Triassic Vera Formation (Los Menucos Complex) in Río Negro Province, southern Argentina. This discovery represents the first record of this family in the Triassic of Argentina and the southernmost record of South American Triassic ‘conchostracans’ (Spinicaudata). The new species shows close affinities with Middle Jurassic faunas from Antarctica and offers important data on the taxonomy (notably the use of ornamentation characters), palaeobiogeography (as South America hosts the oldest-known fossils of this family) and evolution of the Gondwanan faunas. Other South American eosestheriid species are tentatively recognized. Menucoestheria is hypothesized to be the ancestral form of the Triassic–Jurassic Gondwanan eosestheriids. Relationships between European and Gondwanan eosestheriids remain unresolved.     

First record of fossil woods from the Mariño Formation (Miocene), Mendoza,Argentina and their palaeobiogeographical implications

The first Miocene records of silicified fossil woods from the Mariño Formation, Potrerillos area, Andes Precordillera, Mendoza province, Argentina are described. Rhaphithamnoxylon artabeae gen. et sp. nov. is described as the first fossil wood referable to Verbenaceae from Argentina. This new fossil species is related to extant Rhaphithamnus Miers, sharing the following anatomical features: diffuse porosity, distinct growth ring boundaries, numerous small to very small vessels, commonly in radial multiples, 1–3 seriate rays, and heterocellular and scarce paratracheal axial parenchyma. Rhaphithamnus contains only two extant species: R. spinosus (A.L. Juss.) Moldenke, which occurs in the Valdivian forests of Chile and Argentina, and R. venustus (Philippi) Robinson, which is endemic to the Juan Fernández Islands. Representatives of Verbenaceae are distributed predominantly in the Americas from Patagonia (Argentina) to Canada, and they are inferred to have originated in South America. The fossil wood described herein provides new age and geographical constraints on the raphithanoid lineage within Verbenaceae. Other fossil woods recorded from the Mariño level are retained under open nomenclature, as they possess a combination of mostly solitary broad vessels, and smaller vessels in radial multiples or in clusters, with numerous, vasicentric to confluent axial parenchyma, and heterocellular, high rays. Thus, they have features akin to dicotyledonous lianas or vine-like or small shrub species.     

Pennsylvanian (Carboniferous) brachiopods from the Itaituba Formation of the Amazon Basin,Brazil

A new brachiopod fauna is described from the lower Itaituba Formation at the Caima Quarry 2 section in the Itaituba area, Amazon Basin, Brazil. The Amazonoproductus amazonensis-Anthracospirifer oliveirai Assemblage is proposed for this fauna, which is considered early Pennsylvanian (Morrowan) as constrained by associated conodont and fusulinacean faunas. Nine brachiopod taxa are described herein, including Amazonoproductus amazonensis gen. et sp. nov., and Buxtonioides itaitubensis sp. nov. and Linoproductus caima sp. nov. The new tribe Marginovatini of the Linoproductoidea (the Productida) is also proposed.     

A new Late Ordovician microdomatid gastropod genus from Seville,south west Spain,with a revision of Ordovician Microdomatoidea

A new microdomatid gastropod, Eopagodea sevillana gen. and sp. nov., is described from the Late Ordovician (pre-Hirnantian Ashgill) limestones of Seville, Ossa Morena Zone, Spain. Palaeozoic microdomatids lived in shallow-water environments and were restricted to warm-water regions. Occurrence of microdomatid gastropods in the pre-Hirnantian Ashgill limestones of the Cerrón del Hornillo syncline (Ossa Morena Zone, Spain) is interpreted as an example of an influx of warm-water faunal elements into the otherwise cool to cold climate of the Mediterranean region during a short-termed, pre-Hirnantian increase of palaeotemperatures. The Late Ordovician microdomatid genus Daidia Wilson, 1951, is revised and two new Late Ordovician (Ashgill) subspecies of Daidia cerithioides (Salter, 1859) are described: Daidia cerithioides sewardensis n. subsp. from the Don River area of the York Mountains, Seward Peninsula, western Alaska, and Daidia cerithioides wilsonae n. subsp. from the Little East Lake Formation of northwestern Maine.     

Revision of two phragmodontid species (Conodonta) from the Darriwilian (Ordovician) of the Canning Basin in Western Australia and phylogeny of the Cyrtoniodontidae

Zhen, Y.Y. 9 July 2019. Revision of two phragmodontid species (Conodonta) from the Darriwilian (Ordovician) of the Canning Basin in Western Australia and phylogeny of the Cyrtoniodontidae. Alcheringa XX, xxx–xxx. ISSN 0311-5518

Based on re-examination of the material used in the original study from the subsurface Goldwyer and Nita Formations (middle Darriwilian, Middle Ordovician) of the Canning Basin, Western Australia, two phragmodontid species (Phragmodus polystrophos Watson and Ph. spicatus Watson) are revised as having a septimembrate apparatus including geniculate (Ph. polystrophos) or nongeniculate (Ph. spicatus) M, triform alate Sa, modified tertiopedate (Ph. polystrophos) or tripennate (Ph. spicatus) Sb, modified bipennate Sc, modified quadriramate Sd, carminate Pa and pastinate Pb elements. Characterized by a carminate Pa element in their respective species apparatuses, these two species demonstrate a close phylogenetic relationship with Phragmodus cognitus Stauffer from the Late Ordovician (Sandbian) of North America. These distinctive shared characters have allowed their accommodation within a new genus, Protophragmodus gen. nov., which represents an evolutionary lineage separated from species of Phragmodus Branson & Mehl (sensu stricto). In addition, it is postulated that the Cyrtoniodontidae might have originated in the early–middle Darriwilian from ‘Plectodina’ in shallow-water settings, with Phragmodus (sensu stricto), the most derived part of the family, perhaps directly evolving from Protophragmodus gen. nov. in the late Darriwilian and then becoming cosmopolitan, deeper-water dwellers in the Late Ordovician.

Y.Y. Zhen [yong-yi.zhen@planning.nsw.gov.au], Geological Survey of New South Wales, W.B. Clarke Geoscience Centre, 947–953 Londonderry Road, Londonderry, NSW 2753, Australia.