Section: Comparative Discussion Of Ellipsotaphrid Generamentioning
confidence: 99%
“…Type species: Aeglina monophthalma Klouček 1916. Original designation of Whittard 1952, p. 312. From the Dobrotivá Formation, late Darriwilian, (Llandeilian) or earliest Katian, Czech Republic.…”
Section: Systematic Palaeontologymentioning
confidence: 99%
“…Amicus Koroleva 1967 (type species Amicus montanus ) was included by Kobayashi & Hamada (1971) in their Ellipsotaphrinae (herein Ellipsotaphridae) but, as was pointed out by Marek (1977, p. 70), this genus has much more in common with cyclopygid genera now placed in the Pricyclopyginae. Marek also included Whittard's (1952) genus Psilacella in the Ellipsotaphridae, as did Fortey & Owens (1987), largely because of its three linear pairs of glabellar furrows but it is here excluded, as there is nothing in Psilacella comparable with the diagnostic ‘foreglabella’ typical of ellipsotaphrid genera. Psilacella is considered to be probably a micropariine cyclopygid.…”
Following Fortey and Owens (1987), the Ordovician trilobite taxon Ellipsotaphrinae is established as valid, but is argued to have full family status within the Cyclopygoidea. It encompasses the existing genera Ellipsotaphrus, Girvanopyge Gamops and Circulocrania together with two new genera proposed herein, Arisemolobes and Synaptotaphrus. Typical ellipsotaphrid genera have a totally circumscribed ‘foreglabella’, incorporating extended S1 furrows and a portion of the occipital furrow. The known range of the family is Floian to Katian. Genera are conservative in form throughout their ranges and are widespread. All occur only in deeper water sediments with palaeooceanic access. Ellipsotaphrus monophthalmus and Ellipsotaphrus infaustus are reassessed and Ellipsotaphrus zhongguoensis, from the Katian of China, is regarded as a junior synonym of the Katian Girvan species Ellipsotaphrus pumilio. Girvanopyge [ = Cremastoglottos; Nanlingia; Waldminia] is demonstrated, partly on the basis of new material from the Katian of Girvan, to be an ellipsotaphrid cyclopygoid and not to have a close affinity to the remopleuridids, as had been clained. Girvanopyge barrandei, from the Katian of the Czech Republic, is synonymised with Girvanopyge caudata from China. Gamops is revived for forms showing a relationship to both Girvanopyge and Ellipsotaphrus. It encompasses three Czech species including the Dapingian Gamops triangulatus, which probably also occurs in correlative strata in South Wales. The systematic treatment is supported by new material from the Upper Ordovician of the Girvan district, and the relevant geology of this area is described in detail. New species proposed are: Arisemolobes zhouzhiyii, Synaptotaphrus oarion and Circulocrania ? dichaulax.
Section: Comparative Discussion Of Ellipsotaphrid Generamentioning
confidence: 99%
“…Type species: Aeglina monophthalma Klouček 1916. Original designation of Whittard 1952, p. 312. From the Dobrotivá Formation, late Darriwilian, (Llandeilian) or earliest Katian, Czech Republic.…”
Section: Systematic Palaeontologymentioning
confidence: 99%
“…Amicus Koroleva 1967 (type species Amicus montanus ) was included by Kobayashi & Hamada (1971) in their Ellipsotaphrinae (herein Ellipsotaphridae) but, as was pointed out by Marek (1977, p. 70), this genus has much more in common with cyclopygid genera now placed in the Pricyclopyginae. Marek also included Whittard's (1952) genus Psilacella in the Ellipsotaphridae, as did Fortey & Owens (1987), largely because of its three linear pairs of glabellar furrows but it is here excluded, as there is nothing in Psilacella comparable with the diagnostic ‘foreglabella’ typical of ellipsotaphrid genera. Psilacella is considered to be probably a micropariine cyclopygid.…”
Following Fortey and Owens (1987), the Ordovician trilobite taxon Ellipsotaphrinae is established as valid, but is argued to have full family status within the Cyclopygoidea. It encompasses the existing genera Ellipsotaphrus, Girvanopyge Gamops and Circulocrania together with two new genera proposed herein, Arisemolobes and Synaptotaphrus. Typical ellipsotaphrid genera have a totally circumscribed ‘foreglabella’, incorporating extended S1 furrows and a portion of the occipital furrow. The known range of the family is Floian to Katian. Genera are conservative in form throughout their ranges and are widespread. All occur only in deeper water sediments with palaeooceanic access. Ellipsotaphrus monophthalmus and Ellipsotaphrus infaustus are reassessed and Ellipsotaphrus zhongguoensis, from the Katian of China, is regarded as a junior synonym of the Katian Girvan species Ellipsotaphrus pumilio. Girvanopyge [ = Cremastoglottos; Nanlingia; Waldminia] is demonstrated, partly on the basis of new material from the Katian of Girvan, to be an ellipsotaphrid cyclopygoid and not to have a close affinity to the remopleuridids, as had been clained. Girvanopyge barrandei, from the Katian of the Czech Republic, is synonymised with Girvanopyge caudata from China. Gamops is revived for forms showing a relationship to both Girvanopyge and Ellipsotaphrus. It encompasses three Czech species including the Dapingian Gamops triangulatus, which probably also occurs in correlative strata in South Wales. The systematic treatment is supported by new material from the Upper Ordovician of the Girvan district, and the relevant geology of this area is described in detail. New species proposed are: Arisemolobes zhouzhiyii, Synaptotaphrus oarion and Circulocrania ? dichaulax.
“…Fortey and Owens (1978, 1987) suggested correlation of the Henllan Ash Member with the Bolahaul Member or the Pibwr Member, or both, based on its abundant trilobite fauna (Whittington, 1966), and therefore with the middle Moridunian Stage. Graptolites from the uppermost Henllan Ash Member were re-examined by Zalasiewicz (1984), who identified a fauna characterized by Expansograptus cf.…”
The Arenig Fawr area of North Wales constitutes the type area for the British Lower to Middle Ordovician Arenig Series and is complemented by sections in the Carmarthen and Whitland areas of South Wales. We describe chitinozoan assemblages from both areas in order to aid correlation of the Arenig Series in its type region with the global Ordovician series and stages. Chitinozoans recorded from Arenig Fawr provide permissive rather than conclusive evidence but suggest that the Henllan Ash Member correlates with the upper Floian Stage Slice Fl3 or lower Dapingian Stage Slice Dp1. Better results were obtained from South Wales where six chitinozoan assemblages are distinguished, ranging in age from late Tremadocian to middle Darriwilian (early Llanvirn). Most species are known from South China, Gondwana and/or Baltica where there are controls on ranges. They show that much of the lower Arenig (Moridunian) succession in South Wales correlates with the upper Floian Stage (Fl3). Correlatives of the lower and middle Floian Stage (Fl1, Fl2), if present, must be represented by the Ogof Hên Formation and lowest Carmarthen Formation. Chitinozoan assemblages from the upper Arenig Series (Fennian Stage) are more readily correlated with Gondwanan biozones and indicate correlation of the Fennian Stage with the Dapingian and lower Darriwilian (Dw1) stages. The middle Arenig Whitlandian Stage is constrained in South Wales to an interval from the uppermost Floian Stage to the basal Dapingian Stage, resulting in an inferred increased rate of sediment accumulation.
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