Low-latitudinal standard Permian radiolarian biostratigraphy for multiple purposes with Unitary Association, Graphic Correlation, and Bayesian inference methods
“…4.6d of Suzuki and Aita (2012). According to Suzuki and Aita (2012) and Xiao et al (2018), the phylogenetic evolution of the genus can be summarized by the representative two-dimensional images of the eight species. We obtained measures for x c , a, and b from the images and thereby obtained values of the ratios of interest for each image.…”
Section: Discussionmentioning
confidence: 99%
“…This means that the genus is very popular among paleontological researchers. The phylogeny of the genus has been researched in detail (Riedel and Sanfilippo, 1971;Goll, 1972;Kellogg, 1980;Sanfilippo and Riedel, 1980;Suzuki and Aita, 2012;Xiao et al, 2018). There are approximately ten species of Didymocyrtis in the fossil record.…”
This paper discusses the geometrical properties of a radiolarian skeletal structure, namely, that of genus Didymocyrtis. We characterized the evolution of skeletal structures and analyzed the structures using geometry. We defined two ratios in order to quantify the geometrical properties of Didymocyrtis and verified that the two ratios changed with their phylogenic evolution. We also used the 3D skeletal data of a specimen of species D. tetrathalamus, which was obtained through micro X-ray CT. The cortical shell obtained in the 3D data was projected onto a spherical surface, and we determined the centers of the pores. Our analysis revealed that the number of pores is approximately 200 and their distribution is not regular. We also determined that the column-like parts of the skeleton, which connect the inner and upper parts of the specimen, do not lie on a plane and their intervals are not equal.
“…4.6d of Suzuki and Aita (2012). According to Suzuki and Aita (2012) and Xiao et al (2018), the phylogenetic evolution of the genus can be summarized by the representative two-dimensional images of the eight species. We obtained measures for x c , a, and b from the images and thereby obtained values of the ratios of interest for each image.…”
Section: Discussionmentioning
confidence: 99%
“…This means that the genus is very popular among paleontological researchers. The phylogeny of the genus has been researched in detail (Riedel and Sanfilippo, 1971;Goll, 1972;Kellogg, 1980;Sanfilippo and Riedel, 1980;Suzuki and Aita, 2012;Xiao et al, 2018). There are approximately ten species of Didymocyrtis in the fossil record.…”
This paper discusses the geometrical properties of a radiolarian skeletal structure, namely, that of genus Didymocyrtis. We characterized the evolution of skeletal structures and analyzed the structures using geometry. We defined two ratios in order to quantify the geometrical properties of Didymocyrtis and verified that the two ratios changed with their phylogenic evolution. We also used the 3D skeletal data of a specimen of species D. tetrathalamus, which was obtained through micro X-ray CT. The cortical shell obtained in the 3D data was projected onto a spherical surface, and we determined the centers of the pores. Our analysis revealed that the number of pores is approximately 200 and their distribution is not regular. We also determined that the column-like parts of the skeleton, which connect the inner and upper parts of the specimen, do not lie on a plane and their intervals are not equal.
“…The terminology of Follicucullidae species is shown in Figure 1. We adjusted the taxonomic concepts as we have discussed previously (Xiao et al 2018: p. 199). Figure 1.Diagrammatic illustration (not real species) showing the terminology and measured traits of Follicucullidae species (A) and sketch of the type species of the genera (B, Pseudoalbaillella scalprata ; C, Parafollicucullus fusiformis ; D, Longtanella zhengpanshanensis ; E, Kitoconus elongata ; F, Haplodiacanthus anfractus ; G, Holdsworthella permica ; H, Cariver charveti ; I, Curvalbaillella u-forma ; J, Follicucullus ventricosus ; K, Ishigaconus scholasticus ).…”
Section: Methodsmentioning
confidence: 99%
“…Bayesian statistics have been used ever more widely in recent years, including paleontology (e.g., Xiao et al 2018), applying algorithms of probability using the likelihood function based on probability theory and random variables. Bayesian discrimination can predict a sample classification based on prior information, but we could not identify any Bayesian methods that are relevant to HQT-II.…”
The classical taxonomy of fossil invertebrates is based on subjective judgments of morphology, which can cause confusion, because there are no codified standards for the classification of genera. Here, we explore the validity of the genus taxonomy of 75 species and morphospecies of the Follicucullidae, a late Paleozoic family of radiolarians, using a new method, Hayashi's quantification theory II (HQT-II), a general multivariate statistical method for categorical datasets relevant to discriminant analysis. We identify a scheme of 10 genera rather than the currently accepted 3 genera (Follicucullus, Ishigaconus, and Parafollicucullus). As HQT-II cannot incorporate stratigraphic data, a phylogenetic tree of Follicucullidae was reconstructed for 38 species using maximum parsimony. Six lineages emerged, roughly in concordance with the results of HQT-II. Combined with parsimony ancestral state reconstruction, the ancestral group of this family is Haplodiacanthus. Five other groups were discriminated, the Parafollicucullus, Curvalbaillella, Pseudoalbaillella, Longtanella, and Follicucullus–Cariver lineages. The morphological evolution of these lineages comprises a minimum essential list of eight states of four traits. HQT-II is a novel discriminant analytical multivariate method that may be of value in other taxonomic problems of paleobiology.
“…Pseudoalbaillella, a long-lived genus that diversified and dominated in the Late Carboniferous to Middle Permian, became relatively smaller in body size and less abundant in the Follicucullus monacanthus zone (Isozaki, 2009b), and then experienced global extinction before the G-LB (Wang and Yang, 2011). Follicucullus, a dominant genus that appeared in the Capitanian (Isozaki, 2009b;Wang and Yang, 2011;Ito et al, 2016;Xiao et al, 2018), also became less dominant at the end of the Capitanian but survived into the Lopingian (Isozaki, 2009b). In west Texas (USA), these Middle Permian radiolarians all disappeared before the end Capitanian (e.g., Nestell and Nestell, 2010).…”
Section: A Possible Biotic Crisis Of Radiolarian?mentioning
The Capitanian (Guadalupian) witnessed one of the major crises of the Phanerozoic and, like many other extinctions, it coincided with the eruption of large igneous province, in this case the Emeishan Traps of Southwest China. However, the timing and causal relationships of this event are in dispute. This study concentrates on the deep-water chert-mudstone strata of the Gufeng Formation and its transition to the Yinping Formation at Chaohu. Zircons from tuffs in the uppermost Gufeng Formation yield a U-Pb age of 261.6 ± 1.6 Ma, and comparison with sections around Emeishan suggests that they appeared in the Jinogondolella altudaensis conodont zone and persisted to the Jinogondolella xuanhanensis zone. This coincides with the Emeishan eruptions, and suggests that they probably derived from this province. Mineralogical and geochemical characteristics also show the tuffs are of acid volcanogenic origin and have a geochemical fingerprint of the ELIP. Our dating show that a crisis amongst radiolarians and a subsequent productivity decline occurred during the middle Capitanian, prior to the Guadalupian-Lopingian boundary. The Emeishan eruptions began immediately before this, indicating a likely causal relationship between these events. Major regression and marine anoxia/euxinia are two other important extinction-relevant environmental changes that occurred during this critical interval. The late Guadalupian crisis was of comparable magnitude to other mass extinctions (e.g., end-Triassic or end
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
