Trilobite Genera Research Articles

The Cambrian (Paibian–Jiangshanian; Steptoean) dokimocephalid trilobite Deckera Frederickson, 1949 in Laurentian North America

AbstractThe Cambrian dokimocephalid trilobite genus Deckera Frederickson, 1949 is a minor component of Steptoean (Jiangshanian) faunas of Laurentian North America. The original diagnosis emphasized strongly inflated palpebral areas of fixed cheeks and elevated palpebral lobes as important and novel characters. An appraisal of archival and new specimens from Oklahoma, Missouri, Pennsylvania, Nevada, Utah, and Newfoundland show that the genus is geographically widespread and likely represented by as many as nine species, although only two of them are named formally. Deckera cf. D. aldenensis Frederickson, 1949 from Nevada extends the stratigraphic range of Deckera down to the base of the Jiangshanian Stage, and new species from Nevada and Newfoundland take the genus down farther, into upper Paibian strata. Paibian species show that some basal members of the genus have weakly inflated, nearly flat palpebral areas with palpebral lobes that sit well below the crest of the glabella. A revised diagnosis of Deckera focuses on the broad cranidium with width across the palpebral lobes much greater than the sagittal length. Pygidia are known for a few species and all of them have an unusual flexure of the posterior margin and border. Lectotype and paralectotype specimens are designated for Deckera completa.

Revised Paleozoic depositional history of the central Rocky Mountains (Utah and Colorado)

Precise sedimentological, stratigraphic, paleontological, and geochronological data collected from Paleozoic strata of the Dinosaur National Monument (DNM) area (NW Colorado and NE Utah) allow for comprehensive revision of the depositional history of that part of the central Rocky Mountains.Recovery of multiple species of the trilobite genus Elrathiella from sandstone beds in the middle of the Lodore Formation assigns those deposits to the mid-Miaolingian Ehmaniella Zone near the top of the Wuliuan Stage. This is significantly older than the previous “Dresbachian” age estimate for those coarse clastics, which attributed them to deposition during the late Miaolingian (latest Drumian or Guzhangian). This age revision re-positions the southernmost boundary of widespread Miaolingian inner detrital belt deposits of Wyoming to within 90 km of an extensive area of central Colorado where strata of this age are absent, and middle Furongian successions rest directly on basement. The boundary between these two regions, one with and one without Miaolingian strata, is nearly coincident with the Cheyenne belt, an east–west oriented Precambrian continental suture zone at the northern margin of the Yavapai Terrane. This association supports the idea that deep-seated crustal-scale features controlled the Cambrian paleotopography of the Rocky Mountain region and, in turn, the regional pattern of Cambrian transgression across western Laurentia.Early cursory paleontological work suggested a Devonian age for a thick sandstone interval near the top of the Lodore Formation, based on phosphatic fossils. We demonstrate that these fossils are in fact Cambrian obolid brachiopod shells. However, we provide multiple lines of evidence, including carbonate δ13C chemostratigraphic data, distinctive lithofacies, and stratigraphic relationships to argue that a thin interval of shale and dolostone, as well as a previously unrecognized paleokarst and regolith interval at the top of what was mapped as Lodore Formation, are in fact part of the Upper Devonian Parting Formation. The thick sub-Mississippian paleoregolith is consistent with elevated rates of weathering during the Late Devonian–Early Mississippian. δ13C chemostratigraphic data for the Madison Limestone include a large double-peaked Kinderhookian positive isotopic excursion (up to ~6.5 ‰), providing a precise estimate of the timing of Mississippian transgression in this part of the Rocky Mountain region.Detrital zircon geochronologic data for Cambrian to Pennsylvanian strata show remarkably consistent patterns dominated by ~1100 Ma, ~1400 Ma, and ~1700 Ma peaks, reflecting relative igneous quiescence over much of the Paleozoic for this region, a span of ~200 m.y., despite some orogenic activity (e.g., Antler Orogeny, Ancestral Rockies) during that time interval.

Needmorella, a new trilobite genus of the Synphoriinae (Dalmanitidae) from the Lower–Middle Devonian of West Virginia

AbstractThe trilobite Needmorella new genus, with type species N. simoni new genus new species from the late Emsian to mid-Eifelian Needmore Shale of West Virginia, is a distinctive member of the subfamily Synphoriinae. It also occurs in the same formation in Pennsylvania and Virginia. It is not very similar to other Devonian representatives of the subfamily and is considered to have its origins in a morphologically less-derived ancestor because it shares certain similarities with Silurian genera, including the very short anterior cephalic border unmodified by crenulations or spines, S2 that is not largely reduced to a deep pit adaxially, the relatively low inflation of L3, and the well-defined interpleural furrows on the pygidium. Other particularly distinctive characters of the genus include the very long genal spines and the abaxially inflated and expanded posterior pleural bands on the thorax and pygidium that project slightly distally. The conventional concept of the Devonian synphoriine Anchiopsis Delo, 1935 appears to be incompatible with the holotype of the type species, judging from the early illustrations of the specimen, and the genus could be a synonym of Synphoria Clarke, 1894.UUID: http://zoobank.org/4a820e27-54ec-4f7b-a408-675e62b75154

Biogeographic patterns in Late Paleozoic trilobites

Based on cluster and correspondence analysis, Late Paleozoic trilobites are shown to display varying degrees of provincialism and cosmopolitanism through time. These distributional changes appear to coincide temporally with the closing of the Rheic Ocean and the onset and waning of the Late Paleozoic Ice Age. Early Tournaisan trilobite faunas, composed mainly of primitive phillipsid genera, display widespread distribution within ancestral deep-water environments of the Rheic Ocean. Middle to late Tournaisian through early Viséan trilobite genera were segregated into environmentally constrained endemic shelf faunas, and widespread to cosmopolitan deep-water biota. Reduced provincialism during the Serpukhovian is interpreted to have resulted from the onset of the Late Paleozoic Ice Age. Initiation of this profound global environmental perturbation is interpreted to have produced equatorially constricted climate zones and rapidly vacillating sea level and cylothemic deposits that created high levels of ecological stress within marine faunas. Early Pennsylvanian trilobite faunas exhibited weak levels of provincialism on either side of Pangea, with dominant faunal components displaying cosmopolitan tendencies. Trilobite faunas of the late Pennsylvanian were characterized by a few widespread to cosmopolitan genera, that exhibit ecologic generalist tendencies while inhabiting broad geographic and latitudinal ranges. Permian trilobites exhibit a progressive increase in provincialism through time which is interpreted to be the result of the ending of the Late Paleozoic Ice Age and the onset of greenhouse conditions.

A new look at Eccaparadoxides (Cambrian, Trilobita) and its biostratigraphic significance

Eccaparadoxides is a geographically widely distributed trilobite genus that occurs in the middle part of the Cambrian System. However, the systematically important morphologic characteristics that can be used to differentiate taxa are often problematical in their application. A review of the large number (over 30) of significant species or forms assigned to Eccaparadoxides clearly indicates that only the pygidia offer fairly reliable morphologic criteria that can be used taxonomically and phylogenetically. The pygidia allow for recognition of four different morphological groups (pusillus, lamellatus, pradoanus and asturianus) of which the asturianus group can only be questionably assigned to the genus. Species known only from cranidia cannot be assigned to Eccaparadoxides with certainty. This study refines the biostratigraphy for the interval from the upper Wuliuan to the middle Drumian and shows that this interval brackets the range of most Eccaparadoxides species. The genera or subgenera Baltoparadoxides, Rejkocephalus and Macrocerca are evaluated. Eccaparadoxides zelus, E. epimetheus and Eccaparadoxides? hestia are newly proposed species.

The Columbellidae (Gastropoda, Buccinoidea) in the Miocene Paratethys Sea—striking diversity of a negelected group

We document 37 Columbellidae species, placed in 15 genera, from the middle Miocene of the Paratethys Sea, adding about 20% of new species to the previously known Columbellidae fauna of the Paratethys. This distinct increase is based on a careful revision of museum material that was collected during the 19th century. A detailed revision revealed numerous misidentifications of published material, which greatly distorted the understanding of many species in the literature. The revised fauna reveals only minimal affinities with coeval faunas from the Proto-Mediterranean Sea and suggests a palaeogeographic subdivision within the Central Paratethys between northern and southern basins. A major drop in columbellid diversity occurred at the Langhian/Serravallian boundary, coinciding with the Miocene Climatic Transition. This event led to a severe diversity decline from a high Langhian level of 32 species, which was comparable in the number of columbellid species to that of the modern Red Sea and tropical West Africa (~23 species), down to a diversity level of nine species, equalling that of the modern Mediterranean Sea.
 Auingeria nov. gen., Bellacolumbella nov. gen., Martaia nov. gen. and Defensina nov. gen. are introduced as new genera. Mitrella dacica nov. sp., Mitrella demaintenonae nov. sp., Mitrella elongatissima nov. sp., Mitrella viennensis nov. sp. and Zafrona sphaerocorrugata nov. sp. are described as new species. Costoanachis venzoi is proposed as replacement name for Anachis (Costoanachis) subcorrugata Venzo & Pelosio, 1963 non Columbella (Anachis) subcorrugata Boettger, 1906.
 Lectotypes are designated for Columbella (Anachis) guembeli Hoernes & Auinger, 1880, Columbella januskiewiczi Friedberg, 1938, Columbella (Mitrella) fallax Hoernes & Auinger, 1880, Atilia (Macrurella) hilberi Cossmann, 1901, Columbella petersi Hilber, 1879, Columbella (Mitrella) complanata Sacco, 1890, Columbella (Mitrella) bittneri Hoernes & Auinger, 1880, Columbella (Orthurella) elongata var. convexula Sacco, 1890, Columbella (Anachis) moravica Hoernes & Auinger, 1880, Columbella (Mitrella) bucciniformis Hoernes & Auinger, 1880, Columbella (Anachis) haueri Hoernes & Auinger, 1880, Columbella (Anachis) austriaca Hoernes & Auinger, 1880, Pyrene (Anachis) bellardii grussbachensis Csepreghy-Meznerics, 1969, Columbella (Anachis) dujardini Hoernes & Auinger, 1880, Columbella (Anachis) zitteli Hoernes & Auinger, 1880, Columbella (Nitidella) karreri Hoernes & Auinger, 1880, and Columbella (Nitidella) katharinae Hoernes & Auinger, 1880.
 Scabrellana is introduced as replacement name for the trilobite genus Scabrella Wenndorf (1990) non Scabrella Sacco, 1890.

Revision of the late Cambrian trilobite genus Archikainella

Later Cambrian trilobite genera Archikainella and Chencunia are respectively based solely on cranidia and pygidia. An articulated exoskeleton found recently from southwestern Guangxi Zhuang Autonomous Region, South China reveals that these two genera are congeneric, and Chencunia is a junior synonym of Archikainella. The new finding also indicates that Metaacidaspis is a junior synonym of Archikainella. This new articulated material is assigned to the previously described species Archikainella vomerinus. It represents the earliest known articulated lichakephalid trilobite. A malformed thoracic segment is recognized in this specimen, likely caused by teratological/pathological conditions. Xuejian Zhu* [xuejianzhu9@hotmail.com], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China; Shanchi Peng [scpeng@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China; Tatyana V. Pegel [pegel@mail.ru], Siberian Research Institute of Geology, Geophysics and Mineral Resources, Novosibirsk, Russia; Jingxun Zuo [jxzuo2013@sina.com], Henan Institute of Geological Survey, Zhengzhou, China.

Satunarcus, a new late Cambrian trilobite genus from southernmost Thailand and a reevaluation of the subfamily Mansuyiinae Hupé, 1955

AbstractThe Ao Mo Lae Formation of the Tarutao Group crops out on Thailand's Tarutao Island and contains a diverse assemblage of late Furongian trilobite taxa, including several endemic forms. This study presents a new genus and species, Satunarcus molaensis, discovered at two locations on the island. A cladistic analysis of the kaolishaniid subfamily Mansuyiinae in light of Satunarcus and similar genera known from across upper Cambrian equatorial Gondwanan rocks suggests that the subfamily is polyphyletic in its current definition, and thus is not a natural group. Separating Mansuyia Sun, 1924 from the other taxa conventionally placed in Mansuyiinae permits recognition of a previously unrecognized monophyletic subfamily Ceronocarinae new subfamily. As established herein, this kaolishaniid subfamily contains Satunarcus n. gen. and all genera previously recognized as Mansuyiinae. with the exception of Mansuyia itself. Ceronocarinae n. subfam. occur in middle Jiangshanian to middle Cambrian Stage 10 sedimentary rocks from Australia, South China, North China, and Sibumasu, with most genera endemic to Australia.UUID: http://zoobank.org/618c5136-73f0-4912-a7d3-e56559d2a76c

Early Silurian (Llandovery) Trilobite fauna from

The aim of this study is to analyze the assemblage of trilobites in the Silurian sequences of Iran by exploring stratigraphic section of the Silurian Niur Formation (Asadli section). Based on comprehensive field studies and laboratory investigations three Trilobite genera were identified in the study area including Calymene blumenbachii, Gravicalymene convolva, Dalmanites brevigladiolus and Calymene sp. according to this trilobite assemblage a Rhuddanian to Telychian stages (Llandovery) is suggested for deposition of the study strata. The recognized trilobite fauna will be used as a base for future geological studies on the Silurian strata in Kopeh-Dagh Basin. This is the first report of trilobites from the Silurian (Llandovery) Niur Formation in Asadli section, north- east, Iran.

Redefining the Tonto Group of Grand Canyon and recalibrating the Cambrian time scale

Abstract We applied tandem U-Pb dating of detrital zircon (DZ) to redefine the Tonto Group in the Grand Canyon region (Arizona, USA) and to modify the Cambrian time scale. Maximum depositional ages (MDAs) based upon youngest isotope-dilution DZ ages for the Tapeats Sandstone are ≤508.19 ± 0.39 Ma in eastern Grand Canyon, ≤507.68 ± 0.36 Ma in Nevada, and ≤506.64 ± 0.32 Ma in central Arizona. The Sixtymile Formation, locally conformable below the Tapeats Sandstone, has a similar MDA (≤508.6 ± 0.8 Ma) and is here added to the Tonto Group. We combined these precise MDAs with biostratigraphy of trilobite biozones in the Tonto Group. The Tapeats Sandstone is ca. 508–507 Ma; the Bright Angel Formation contains Olenellus, Glossopleura, and Ehmaniella biozones and is ca. 507–502 Ma; and the Muav Formation contains Bolaspidella and Cedaria biozones and is ca. 502–499 Ma. The Frenchman Mountain Dolostone is conformable above the Muav Formation and part of the same transgression; it replaces McKee’s Undifferentiated Dolomite as part of the Tonto Group; it contains the Crepicephalus Biozone and is 498–497 Ma. The Tonto Group thickens east to west, from 250 m to 830 m, due to ∼300 m of westward thickening of carbonates plus ∼300 m of eastward beveling beneath the sub-Devonian disconformity. The trilobite genus Olenellus occurs in western but not eastern Grand Canyon; it has its last appearance datum (LAD) in the Bright Angel Formation ∼45 m above the ≤507.68 Ma horizon. This extinction event is estimated to be ca. 506.5 Ma and is two biozones below the Series 2–Miaolingian Epoch boundary, which we estimate to be ca. 506 Ma. Continued tandem dating of detrital grains in stratigraphic context, combined with trilobite biostratigraphy, offers rich potential to recalibrate the tempo and dynamics of Cambrian Earth systems.

The lower Ovetian Stage (lower Cambrian Stage 3) trilobite zonation in Spain and correlation with West Gondwana

ABSTRACT New trilobites from the upper part of the Pusa Formation (base of Cambrian Stage 3) in Central Spain are studied for their systematic and biostratigraphic significance. The trilobites Proabadiella toletana n. gen. et sp., Proabadiella vidalii n. gen. et sp., and a genus et species indet. are recorded with other fossils from the lower Ovetian regional Stage and archaeocyathan Zone I, which had, until now, provided only undetermined trilobites. The Proabadiella morphology is intermediate between that of the oldest genera of trilobites belonging to the families Abadiellidae and Bigotinidae, confirming the old age inferred for the new trilobites co-occurring with the archaeocyathan assemblage. Our findings permit presenting a new trilobite zonation for the lower Ovetian regional Stage (lower Cambrian Stage 3). A correlation is proposed with the other stratigraphically lowermost trilobites recorded globally.

Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities

Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.

Cambrian trilobites from the Huérmeda Formation (Iberian Chains, north‐east Spain) and the inadequacy of the Marianian Stage

AbstractA taxonomic study of the trilobites found in the Marianian parastratotype of the Iberian Chains, north‐east Spain, results in the recognition of the new redlichiid Redlichia isuelaensis sp. nov., the ellipsocephalid Lusatiops ribotanus, and the saukiandids Onaraspis garciae sp. nov., Paulaspis tiergaensis gen. et sp. nov. and Luciaspis matiasi gen. et sp. nov. The diagnosis of the new Subfamily Onaraspininae (Saukiandidae) and its genera takes into account distinct differences in the thorax, which is subdivided into prothorax with spinose and/or macropleural tergites and opistothorax with micropleurid segments. Onaraspis geyeri sp. nov. is erected based on material previously described in Jordan, which was assigned to poorly preserved material of Myopsolenites palmeri from Israel. The temporal correlation of Marianian endemic‐dominant trilobites throughout the Variscan tectonostratigraphic units of the Iberian Peninsula is not supported by acritarchs, archaeocyaths or trilobites. Three diachronous horizons have been proposed to mark the base of the Marianian (based on the first occurrence of two trilobite genera and one archaeocyathan assemblage zone) and two diachronous horizons for the top (based on the first and last occurrence of different trilobite genera). As a result, the Cambrian Epoch‐2 Marianian Stage is ill‐defined and rendered invalid for correlation throughout the Iberian Peninsula.

Inferring ancestral range reconstruction based on trilobite records: a study-case on Metacryphaeus (Phacopida, Calmoniidae)

Metacryphaeus is a calmoniid trilobite genus from the Devonian Malvinokaffric Realm, exclusive to the Gondwanan regions. It includes eleven species, which are for the first time included here in a single phylogenetic analysis. The resulting hypotheses establish relations among the Metacryphaeus species with few ambiguities, also suggesting the inclusion of both Plesiomalvinella pujravii and P. boulei within the genus, as originally considered. The results of palaeobiogeographic analyses employing the Dispersal-Extinction-Cladogenesis (DEC) model reinforce the hypothesis that Bolivia and Peru form the ancestral home of Metacryphaeus. The radiation of the genus to other Gondwanan areas took place during transgressive eustatic episodes during the Lochkovian–Pragian. The Lochkovian dispersal occurred from Bolivia and Peru to Brazil (Paraná and Parnaíba basins) and the Falklands, and Pragian dispersal occurred towards South Africa. Dispersal events from Bolivia and Peru to the Parnaíba Basin (Brazil) were identified during the Lochkovian–Pragian, suggesting the presence of marine connections between those areas earlier than previously thought.

A new trilobite species from the upper Rhuddanian (lower Silurian) of South China, and its biogeographical implications

Wei, X. & Zhan, R. B., 20 September 2018. A new trilobite species from the upper Rhuddanian (lower Silurian) of South China, and its biogeographical implications. Alcheringa 43, 33–42. ISSN 0311-5518.Xin Wei [xwei@nigpas.ac.cn]. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Science and Technology of China, Hefei, 230026, PR China; Renbin Zhan [rbzhan@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, PR China; University of Chinese Academy of Science, Beijing, 100049, PR China.Anacaenaspis yanpingensis sp. nov., from the lower Niuchang Formation (upper Rhuddanian, lower Llandovery, lower Silurian), is the first record of this genus from South China. The biogeographical distribution of Anacaenaspis and some other trilobite genera from South China (e.g., Gaotania, Hyrokybe, Aulacopleura and Raphiophorus) in the Llandovery evidences faunal exchanges between Avalonia–Baltica, Laurentia, Australia and South China. We attribute these dispersals to prevailing ocean currents, and especially equatorial countercurrents, which would have propagated dispersals during the Rhuddanian, shortly after the end-Ordovician mass extinction.

The homonyms Brachypleura Angelin, 1854 (Trilobita) and Brachypleura Günther, 1862 (Actinopterygii) with discussion of N. P. Angelin's published work

Abstract. The trilobite genus Brachypleura Angelin, 1854 (type species Remopleurides sexlineatus, Angelin, 1851) is a homonym of Brachypleura Gunther, 1862 applied to a species of flounder, and has priority over the latter. The holotype of the type species of Brachypleura is well preserved and was figured by Nikolaisen (1983). Brachypleura Angelin, 1854 is not synonymous with the trilobite genus Amphitryon Hawle & Corda, 1847. Sculptaspis Nikolaisen, 1983 is a junior subjective synonym of Brachypleura Angelin, 1854. The details of the publications by Nils Peter Angelin (1851–52, 1854, 1878) are discussed in detail.

Revision of Diagnostic Features of the Trilobite Genus Bhargavia (Ellipsocephaloidea) from the Parahio Valley (Spiti), Northwest Himalaya, India

Revision of Diagnostic Features of the Trilobite Genus Bhargavia (Ellipsocephaloidea) from the Parahio Valley (Spiti), Northwest Himalaya, India

The middle lower Cambrian (Ovetian)Lunagraulosn. gen. from Spain and the oldest trilobite records

AbstractThe type material ofAgraulos antiquusSdzuy, 1961 from the La Herrería Formation, northern Spain, is revised together with additional material and included in the new genusLunagraulos. The stratigraphical range ofLunagraulos antiquus(Sdzuy, 1961) – occurring below that of the trilobite species of the generaLunolenus,MetadoxidesandDolerolenusin the type locality of Los Barrios de Luna in the province of León, northern Spain – and the accompanying ichnofossil assemblage demonstrate an Ovetian age (lower part of Cambrian Stage 3, currently being discussed by the International Subcommission on Cambrian Stratigraphy) for this species. Moreover, the trilobiteLunagraulos tamamensisn. gen. n. sp. is found in the Tamames Sandstone near the village of La Rinconada in the province of Salamanca, central Spain. The biostratigraphical position of this new taxon and its accompanying ichnoassemblage is also analysed and assigned to the lowermost Ovetian Stage. The genusLunagraulosis therefore the oldest agraulid found in the fossil record. The exceptional presence ofLunagraulosin a marine coarse siliciclastic succession – a facies rather typical for the ichnofossilsCruzianaandRusophycus, some of the oldest signs of trilobite activity – suggests that first trilobite representatives may have inhabited high- to middle-energy, marine environments. This hypothesis may also explain both the taxonomic and biostratigraphic heterogeneity of the first trilobite genera appearing across the world, due to preservation problems in this type of facies. Comparison of theLunagraulos biostratigraphy with other coeval Spanish fossil assemblages allows us to propose its intercontinental correlation with the oldest records of currently known trilobites.

Agraulos longicephalus and Proampyx? depressus (Trilobita) from the Middle Cambrian of Bornholm, Denmark

The trilobite genus Agraulos Hawle & Corda 1847 has within Scandinavia been recorded only from Bornholm, Denmark, where its representatives occur in the Middle Cambrian Paradoxides paradoxissimus Superzone of the Alum Shale Formation. Only cranidia have been found so far, representing Agraulos longicephalus (Hicks 1872) and the rare “Agraulos” depressus Grönwall 1902.

Lower Ordovician trilobites from the Septembersø formation, North-East Greenland

McCobb, L.M.E., Boyce, W.D., Knight, I. & Stouge, S., 2014. Lower Ordovician trilobites from the Septembersø formation, North-East Greenland. Alcheringa 38, 575–598. ISSN 0311-5518.The informally named Septembersø formation is a 76 m thick succession of microbial and peritidal shelf carbonates deposited on the North-East Greenland shelf of Laurentia. The formation, assigned to the lower part of the Cape Weber Formation in all previous studies, lies disconformably upon the Skullrockian Antiklinalbugt Formation (revised) and conformably below the Tulean to Blackhillsian Cape Weber Formation (revised) in the Fimbulfjeld Group. With the exception of Randaynia, the modest trilobite fauna recovered from the Septembersø formation consists exclusively of bathyurids, and all represent new species. Both Chapmanopyge knudseni sp. nov. and Punka adamsi sp. nov. are represented by sufficient material to merit specific names. The remaining taxa, belonging to Bolbocephalus, Peltabellia, Randaynia and Chapmanopyge are left in open nomenclature. The trilobite genera present suggest that the Septembersø formation is referable to the Tulean Stage of the Ibexian Series, latest Tremadocian/earliest Floian in Global Standard terms.Lucy M. E. McCobb [lucy.mccobb@museumwales.ac.uk], Department of Natural Sciences, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, UK; W. Douglas Boyce [dougboyce@gov.nl.ca] and Ian Knight [ianknight@gov.nl.ca], Geological Survey, Newfoundland and Labrador Department of Natural Resources, PO Box 8700, St. John’s, NL, Canada A1B 4J6; Svend Stouge [svends@snm.ku.dk], Natural History Museum of Denmark (Geological Museum), Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark.