Late Ordovician cephalopods,tentaculitides, machaeridians and echinoderms from Kuh-e Faraghan,High Zagros,Iran

Ghavidel-Syooki, M., Evans, D.H., Ghobadi Pour, M., Popov, L.E., Álvaro, J.J., Rakhmonov, U., Klishevich, I.A. & Ehsani, M.D., 15.5.2015. Late Ordovician cephalopods, tentaculitides, machaeridians and echinoderm columnals from Kuh-e Faraghun, High Zagros, Iran. Alcheringa 39, 530–549. ISSN 0311-5518.

Late Ordovician (Katian, uppermost Acanthochitina barbata to Armoricochitina nigerica chitinozoan zones) cephalopods, tentaculitides, machaeridians and echinoderms are documented for the first time from the southern Zagros Ranges. A low-diversity cephalopod fauna includes Geisonocerina dargazense sp. nov., Isorthoceras sp. cf. I. bisignatum (Barrande) and other undetermined orthoceratides. The presence of Late Ordovician tentaculitides in the high- to mid-latitude margins of Gondwana has been documented previously, but no examples have been described in detail. Thus, Costatulites kimi sp. nov., which currently occurs associated with brachiopods characteristic of the Svobodaina havliceki (brachiopod) Association, represents the earliest undoubted record of tentaculitides in Gondwana. Machaeridians constitute a relatively common component of the Late Ordovician benthic faunas from the Mediterranean margin of Gondwana, but no previous records on the Gondwanan Iranian-Arabian segment have been reported. Three echinoderm taxa based on dissociated columnals are documented from the Armoricochitina nigerica chitinozoan Zone, including Sumsaricystis radiatus Stukalina, Ristnacrinus sp. and Rosulicrinus rosulus Stukalina.

Mohammad Ghavidel-Syooki [m_ghavidelsyooki@yahoo.com] Institute of Petroleum Engineering, Technical Faculty of Tehran University, PO Box 11365-4563, Tehran, Iran; David H. Evans [david.evans@naturalengland.org.uk], Natural England, Suite D, Unex House, Bourges Boulevard, Peterborough PE1 1NG, UK; Mansoureh Ghobadi Pour* [mghobadipour@yahoo.co.uk], Department of Geology, Faculty of Sciences, Golestan University, Gorgan, Iran; Leonid E. Popov [leonid.popov@museumwales.ac.uk], Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, UK; J. Javier Álvaro [jj.alvaro@csic.es], Instituto de Geociencias (CSIC-UCM), c/ José Antonio Novais 2, 28040 Madrid, Spain; Utkyr Rakhmonov, Kitab State Geological Reserve, 9 Ipak Yuli Street, Sakhrisabz, Uzbekistan; Inna A. Klishevich, Department of Historical Geology, Geological Faculty, St Petersburg State University, Universitetskaya Naberezhnaya 7/9, 199034 St Petersburg, Russia [inna@IK4848.spb.edu]; Mohammad H. Ehsani [mh_ehsani@hotmail.com], Institute of Petroleum Engineering, Technical Faculty of Tehran University, PO Box 11365-4563, Tehran, Iran. *Also affiliated with Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, UK.     

Fauna and biostratigraphy of the Cambrian (Series 2, Stage 4; Ordian) Tempe Formation (Pertaoorrta Group), Amadeus Basin,Northern Territory

A new faunal assemblage is reported from the Tempe Formation (Cambrian Series 2, Stage 4; Ordian) retrieved from the Hermannsburg 41 drillcore, Amadeus Basin, central Australia. Two trilobite taxa, including one new species Gunnia fava sp. nov., four brachiopod taxa, including the age-diagnostic Karathele napuru (Kruse), Kostjubella djagoran (Kruse) and Micromitra nerranubawu Kruse, together with a bradoriid, helcionellids, hyoliths, echinoderms, chancelloriids, sponges and problematic tubes are described. The fauna has close links to those of the neighbouring Daly, Georgina and Wiso basins and suggests that the Tempe Formation correlates with the Australian Ordian stage (either the Redlichia forresti or Xystridura negrina assemblage zones). The Giles Creek Dolostone in the eastern Amadeus Basin, previously regarded as coeval with the Tempe Formation, has recently been reported to be of early Templetonian age in its type section. The described taxa from the Tempe Formation confirm that these two sedimentary units are not contemporaneous and that regional stratigraphic schemes should be amended.     

Permian non-marine bivalves of the Falkland Islands and their palaeoenvironmental significance

Simões, M.G., Quaglio, F., Warren, L., Anelli, L.E., Stone, P., Riccomini, C., Grohmann, C.H. & Chamani, M.A.C. December 2012. Permian non-marine bivalves of the Falkland Islands and their palaeoenvironmental significance. Alcheringa 36, 543–554. ISSN 0311-5518.

We describe the occurrence of non-marine bivalves in exposures of the Middle Permian (Capitanian) Brenton Loch Formation on the southern shore of Choiseul Sound, East Falklands. The bivalves are associated with ichnofossils and were collected from a bed in the upper part of the formation, within a 25 cm thick interval of dark siltstones and mudstones with planar lamination, overlain by massive sandstones. The shells are articulated, with the valves either splayed open or closed. At the top of the succession, mudstone beds nearly 1.5 m above the bivalve-bearing layers yielded well-preserved Glossopteris sp. cf. G. communis leaf fossils. The closed articulated condition of some shells indicates preservation under high sedimentation rates with low residence time of bioclasts at the sediment/water interface. However, the presence of specimens with splayed shells is usually correlated to the slow decay of the shell ligament in oxygen-deficient bottom waters. The presence of complete carbonized leaves of Glossopteris associated with the bivalve-bearing levels also suggests a possibly dysoxic-anoxic bottom environment. Overall, our data suggest that the bivalves were preserved by abrupt burial, possibly by distal sediment flows into a Brenton Loch lake, and may represent autochthonous to parautochthonous fossil accumulations. The shells resemble those of anthracosiids and are herein assigned to Palaeanodonta sp. aff. P. dubia, a species also found in the Permian succession of the Karoo Basin, South Africa. Our results confirm that (a) the true distributions in space and time of all Permian non-marine (freshwater) bivalves are not yet well known, and (b) there is no evidence for marine conditions in the upper part of the Brenton Loch Formation.     

Palynology of glacial sediments from the Guandacol Formation (Middle Carboniferous) in the Cerro Bola area,Paganzo Basin,Argentina

The palynoflora of surface samples of glacial deposits from the Guandacol Formation in the Cerro Bola area of the Argentinian Paganzo Basin is documented. The existence of glacial related diamictites in this area has been previously ignored. The fossiliferous levels are located in section B of the formation, which corresponds to the earlier stages of deglaciation. The assemblage contains abundant monosaccate pollen grains whose global incoming is not older than early Namurian (Middle Carboniferous). Many species of this palynoflora are present in equivalent stratigraphic sequences of Argentina and can be referred to Sub-biozone A of the Raistrickia densa-Convolutispora muriornata Biozone (Namurian-Stephanian). New species described here are Cyclogranisporites rinconadensis and Tricidarisporites gutii.     

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.     

The architecture of Permian glossopterid ovuliferous reproductive organs

McLoughlin, S. & Prevec, R. 20 September 2019. The architecture of Permian glossopterid ovuliferous reproductive organs. Alcheringa XX, xxx–xxx. ISSN 0311-5518

A historical account of research on glossopterid ovuliferous reproductive structures reveals starkly contrasting interpretations of their architecture and homologies from the earliest investigations. The diversity of interpretations has led to the establishment of a multitude of genera for these fossil organs, many of the taxa being synonymous. We identify a need for taxonomic revision of these genera to clearly demarcate taxa before they can be used effectively as palaeobiogeographic or biostratigraphic indices. Our assessment of fructification features based on extensive studies of adpression and permineralized fossils reveals that many of the character states for glossopterids used in previous phylogenetic analyses are erroneous. We interpret glossopterid fertiligers to have been borne in loose strobili in which individual polysperms represent fertile cladodes of diverse morphologies subtended by a vegetative leaf or bract. Polysperms within the group are variously branched or condensed with ovule placement ranging from marginal to abaxial, in some cases occurring on recurved branchlets or in cupule-like structures. Glossopterid polysperms of all types are fringed by one or two ranks of wing-like structures that may represent the remnants of megasporophylls that were, ancestrally, developed on the fertile axillary shoot. Glossopterid fertiligers have similarities to the condensed bract/ovuliferous scale complexes of conifer cones, but comparisons with Mesozoic seed-ferns are hindered by insufficient data on the arrangement and homologies of the ovule-bearing organs of the latter group. Nevertheless, glossopterid polysperms differ from the ovuliferous organs of Mesozoic seed-ferns by longitudinal versus transverse folding, respectively.

Stephen McLoughlin* [steve.mcloughlin@nrm.se], Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, Sweden; Rose Prevec [r.prevec@am.org.za], Department of Earth Sciences, Albany Museum, 40 Somerset Street, Makhanda, 6139, Eastern Cape, South Africa, and Department of Botany, Rhodes University, PO Box 94, Makhanda, 6140, Eastern Cape, South Africa.     

New occurrence of Cambroclavus absonus from the lowermost Cambrian of North China and its stratigraphical importance

Li, L.-Y., Zhang, X.-L., Yun, H. & Li, G.-X., October 2015. New occurrence of Cambroclavus absonus from the lowermost Cambrian of North China and its stratigraphical importance. Alcheringa 40, xxx–xxx. ISSN 0311-5518.

The problematic Small Shelly Fossil Cambroclavus absonus is described from the Xinji Formation in the Longxian area, which is located near the southwestern margin of the North China Platform. The Xinji Formation, the basal rock unit of the Cambrian in the studied area, yields an assemblage of skeletal fossils that share many common elements with contemporary faunas from South Australia. Sclerites of C. absonus reported herein represent the first occurrence of the species outside Australia, thus extending the palaeogeographic range of the taxon to northern China. To date, palaeogeographic occurrences of Cambroclavus sclerites are restricted to the Peri-Gondwana realm, including South China, Australia, Tarim, Kazakhstan, North China and Western Europe. These occurrences are divided into a Southern Group realm and Northern Group realm. Stratigraphically, Cambroclavus occurs mostly in Cambrian Stage 3 and has three occurrences in Stage 5, separated by Stage 4 in which Cambroclavus has not yet been found. The first appearance datum of Cambroclavus in Cambrian Stage 3 is of importance for regional and inter-regional correlations. In particular, the presence of Cambroclavus absonus in North China allows species-level correlation between North China and South Australia.

Luoyang Li [lly@stumail.nwu.edu.cn], Xingliang Zhang [xzhang69@nwu.edu.cn], Hao Yun [yunhao@stumail.nwu.edu.cn], Early Life Institute and State Key Laboratory Of Continental Dynamics, Department of Geology, Northwest University, Xian 710069, PR China; Guoxiang Li [gxli@nigpas.ac.cn], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, PR China.     

Spondylodendron pranabii—the dominant lycopsid of the late Mississippian vegetation of the Kashmir Himalaya

Cleal, C.J., Bhat, G.M., Singh, K.J., Dar, A.M., Saxena, A. & Chandra, S., February 2016. Spondylodendron pranabii—the dominant lycopsid of the late Mississippian vegetation of the Kashmir Himalaya. Alcheringa 40, xxx–xxx. ISSN 0311-5518.

The Sepukhovian fossil floras of the northern margins of Gondwana, on the shores of the Palaeotethys, are dominated by remains of an eligulate, mainly monopodial lycopsid with persistent leaves. The stems show considerable morphological and preservational variation that has historically resulted in the fossils having been assigned to many fossil-species and -genera. However, there is now clear evidence that this simply reflects variation within a single fossil-species, reflecting biological variation and the effects of variable taphonomy, for which the correct taxonomic name is Spondylodendron pranabii (Pal) comb. nov. Part of this morphological variation might have been due to variations in growth rate during the life of the individual plants, which in turn might reflect stressed growing conditions in a wetland habitat. The systematic position of Spondylodendron remains uncertain, owing to the lack of unequivocal evidence of reproductive structures, but it might have affinities with the Sublepidodendraceae.

Christopher J. Cleal [chris.cleal@museumwales.ac.uk], Department of Natural Sciences, National Museum Wales, Cathays Park, Cardiff CF10 3NP, UK; G.M. Bhat [bhatgm@jugaa.com] and A.M. Dar, Department of Geology, University of Jammu, Jammu, India; Kamal Jeet Singh, [kamaljeet31@hotmail.com] and Anju Saxena [anju_saxena2002@yahoo.co.in], Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226007, (U.P.) India; Shaila Chandra, Flat Number 105, Beverly Park Apartment 422, New Hyderabad, Lucknow-226007, (U.P.) India.