Ontogenetic and intraspecific variation in the late Emsian – Eifelian (Devonian) conodonts Polygnathus serotinus and P. bultyncki in the Prague Basin (Czech Republic) and Nevada (western U.S.)
TL;DR: The stratigraphic distribution of these three species and the conodont zonation across the Emsian-Eifelian (Lower-Middle Devonian) boundary is reviewed and a decrease in the pit size during ontogeny in P. bultyncki is observed, although it is not confirmed whether intraspecific versus ontogenetic variation.
Abstract: Samples from populations of Polygnathus serotinus Telford 1975 and P. bultyncki Weddige 1977 from the Prague Basin and Nevada display normal variation for Devonian conodont species. A considerable number of previous authors, however, have proposed unnecessary synonyms of these two species, primarily because they have not recognized ontogenetic variation. In contrast, we interpret the variation as ontogenetic as well as intraspecific and present detailed synonymies as a result. A third species, P. praetrigonicus Bardashev 1992, which has been carried in open nomenclature for many years, is an important indicator of the basal costatus Zone in the Prague Basin, New York, and Nevada. We review the stratigraphic distribution of these three species and the conodont zonation across the Emsian-Eifelian (Lower-Middle Devonian) boundary. Polygnathus pseudocostatus sp. nov. (partitus-costatus zones, central Nevada) is described herein. We have observed a decrease in the pit size during ontogeny in P. bultyncki although we have not measured enough specimens to rule out intraspecific versus ontogenetic variation.
Citations
More filters
TL;DR: In this article, the Basal Choteč Event (BCE) at its type locality (Na Škrábku Quarry, Czech Republic) and selected sections of time-equivalent strata in the Appalachian Basin (USA), palynomorphs and dacryoconarids have proven responsive to changing environmental conditions.
Abstract: Abstract During recent studies of the Basal Choteč Event (BCE) at its type locality (Na Škrábku Quarry at Choteč Village, Prague Basin of the Barrandian area, Czech Republic) and selected sections of time-equivalent strata in the Appalachian Basin (USA), palynomorphs and dacryoconarids have proven responsive to changing environmental conditions. To date, there have been no detailed reports of dacryoconarids from the Appalachian Basin (AB) and none of palynomorphs from Bohemia or elsewhere. Palynomorphs of the Barrandian area comprise a more or less monospecific assemblage of prasinophycean algae interpreted here to represent an ecological epibole. Mazuelloids and scolecodonts are also present, whereas acritarchs, spores and chitinozoans are accessory components. Prasinophytes also predominate in coeval strata of the Appalachian Basin's northern region, whereas a chitinozoan species and morphotypes possibly assignable to fungi abound in the central region. Scolecodonts and acritarchs are regionally variable throughout the interval. The former are rare in the central region of the basin but are ubiquitous and sometimes abundant in the northern region. Dacryoconarids of the Appalachian Basin are also regionally variable. The dacryoconarid fauna of the northern region, however, descended from a previous Emsian fauna that diversified during the BCE and subsequently functioned as the foundation of the upper Eifelian faunas, while dacryoconarids of the central region represent an incursion epibole of Old World forms that entered the basin at the onset of the event interval and became extinct at its close. Among the dacryoconarids there are key taxa that serve as excellent biostratigraphic markers to identify the BCE in the Appalachian Basin. In both the Prague and Appalachian basins, the BCE occurs near the maximum transgression of the Devonian Ic sequence. Additional faunal changes are found in the Appalachian Basin leading up to the main body of the event.
15 citations
Cites background from "Ontogenetic and intraspecific varia..."
...Significant studies include papers by Klapper (1977), Klapper et al. (1978), Chlupáč et al. (1977), Weddige & Ziegler (1987), Galle & Hladil (1991), Zusková (1991), Hladil & Kalvoda (1993) and Klapper & Vodrážková (2013)....
[...]
TL;DR: In this article, the conodont biozonation of the Early Devonian interval (basal Lochkovian-early Emsian) in the Prague Synform includes 17 biozones.
13 citations
TL;DR: Analysis of pattern of variation in the number of dorso ventral files of eye lenses in two Devonian phacopid trilobites from the Prague Basin of the Czech Republic indicates that caution must be taken for taxonomical affiliation and biodiversity analyses of taxa in which the intraspecific variability is unclear.
Abstract: Arthropods are known to display a variable number of eye lenses and this number mostly increases during their development. In trilobites, most species possessing schizochroal eyes exhibit a notable intraspecific variation in the number of dorso ventral files of eye lenses that can be age related (i.e., growth) or not (i.e., living environment). Several previous studies have shown that some trilobite groups (e.g. phacopids) tend to have fewer lenses/files in representatives from the deeper habitats than those from shallower habitats. In this study, we analyzed the pattern of variation in the number of dorso ventral files of eye lenses in two Devonian phacopid trilobites from the Prague Basin of the Czech Republic. We quantified their intraspecific variability. To better understand the patterning, we compared more than 120 individuals. Data first reveal evidence of a bimodal distribution of lens/file number without intermediate forms among each of two studied populations of Prokops prokopi (Chlupac, 1971) and throughout the ontogeny of Pedinopariops insequens (Chlupac, 1977). Our results indicate that caution must be taken for taxonomical affiliation and biodiversity analyses of taxa in which the intraspecific variability is unclear. Additionally, we investigated possible relations of these bimodalities to the stratigraphical position of studied populations and to the paleoenvironment. In Prokops prokopi, a slightly different age of both populations, together with supposed differences in the local environments can be responsible for observed variability. In Pedinopariops insequens, stress conditions possibly related to the approaching onset of the Basal Chotec Event can be responsible for surprising intrapopulation variability. We speculate that the stress conditions could cause a bimodal selection and possibly also the change of ontogenetic trajectory within this species. Pedinopariops insequens was the only phacopid in the Prague Basin that crosses the Lower/Middle Devonian boundary and survived also the onset of Basal Chotec Event.
8 citations
TL;DR: Wright et al. as discussed by the authors described the operculate coral Calceola gervillei Bayle, 1878, from Early Devonian (likely upper Lochkovian to lower Pragian) strata, and is chosen as the type species of the monotypic new genus Gerviphyllum.
Abstract: Wright, A.J., Plusquellec, Y. & Gourvennec, R., February 2016. Devonian operculate corals (Calceolidae, Cnidaria) from the Massif Armoricain, France. Alcheringa 40, xxx–xxx. ISSN 0311-5518The operculate coral Calceola gervillei Bayle, 1878 is described for the first time on the basis of the type material from the Cotentin region of Normandy (North Armorican Domain), from Early Devonian (likely upper Lochkovian to lower Pragian) strata, and is chosen as the type species of the monotypic new genus Gerviphyllum. The new genus is also present in the l’Armorique Formation (lower Pragian) of the Plougastel Peninsula (Central Armorican Domain) as Gerviphyllum sp. cf. G. gervillei. One locality in the upper Emsian (Polygnathus serotinus Conodont Zone) Le Fret Formation, on the northern coast of the Crozon Peninsula, has yielded operculate coral specimens described here as ?Chakeola sp., the first (tentative) record of the genus outside eastern Australia, south China and Vietnam. The operculate coral Calceola coll...
Cites methods from "Ontogenetic and intraspecific varia..."
...In citing zonally important Armorican polygnathid conodont species, we follow Mawson & Talent (2003) and Klapper & Vodrážková (2013) in using Polygnathus; CZ = conodont zone....
[...]
References
More filters
01 Jan 1978
TL;DR: The regional dimension is highlighted in this context because most renewable energy projects are carried out on local scale, based on the regional resource potential and vulnerability to climate change is very much determined by regional land use and the location of energy infrastructure.
Abstract: Little scientific evidence is presently available on the actual impacts of climate change effects on the energy system. The possible affections have mainly been identified as a result of modelling exercises, which implies a high level of uncertainty with regard to the actual speed and extent of climate variations. The severest impacts are expected to occur in the longer-term horizon (between 2070 and 2100), but many experts, including the IPPC, warn of the risk of non-linear climate change and that changes may be quicker than expected. The regional dimension is highlighted in this context because most renewable energy projects are carried out on local scale, based on the regional resource potential. Furthermore, vulnerability to climate change is very much determined by regional land use and the location of energy infrastructure. It is therefore necessary that planners, law makers and companies design robust strategies for the sustainable development of local energy resources and the protection of the critical infrastructure.
1,432 citations
Book•
13 Oct 1988
TL;DR: Introduction Skeletal anatomy Whole animal anatomy Taxonomy The major conodont groups Paleoecology The phylum Conodonta Evolutionary patterns Appendixes Index
Abstract: Introduction Skeletal anatomy Whole animal anatomy Taxonomy The major conodont groups Paleoecology The phylum Conodonta Evolutionary patterns Appendixes Index
401 citations
"Ontogenetic and intraspecific varia..." refers background or methods in this paper
...[For the standard terminology used here, see Clark and Müller (1968) and Sweet (1981, 1988)]....
[...]
...…would have implications for the mode of formation of the “inverted cavity” (Lindström 1964; Lindström and Ziegler 1971), termed a “zone of recessive basal margin” (Sweet 1981, p. W9; Sweet 1988, textfigs 2.1, 2.5), or an “everted” basal cavity (von Bitter et al. 1986, p. 35; also p. 6–7)....
[...]
Journal Article•
167 citations
"Ontogenetic and intraspecific varia..." refers background in this paper
...…several authors as separate species, P. foliformis and P. totensis, both proposed by Snigireva (1975, see synonymy), but Weddige (1977), Klapper (1977), Pickett (1978, p. 102), Klapper and Johnson (1980) and Mawson (1987a) recognized that P. totensis represents immature specimens of P. serotinus....
[...]
01 Jan 1984
132 citations
"Ontogenetic and intraspecific varia..." refers background in this paper
...Note that once the costatus Zone was dropped as a name for an upper Famennian standard conodont zone (Ziegler and Sandberg 1984), the Eifelian zone came to be termed simply the costatus Zone (Johnson et al. 1986, p. 179)....
[...]
...Note that once the costatus Zone was dropped as a name for an upper Famennian standard conodont zone (Ziegler and Sandberg 1984), the Eifelian zone came to be termed simply the costatus Zone (Johnson et al....
[...]
97 citations
"Ontogenetic and intraspecific varia..." refers background in this paper
...The first occurrence of P. partitus, and consequently the base of the partitus Zone, were accepted as the defining level for the Lower (Emsian) – Middle Devonian (Eifelian) boundary by the International Commission on Stratigraphy in 1982 (Cowie et al. 1989, p. 81)....
[...]