Evolutionary trends of the genus Ancyrogondolella (Conodonta) and related taxa in the Norian (Late Triassic)

Karádi, Viktor

doi:10.1007/s12583-020-1381-z

Cited by 13 publications

(6 citation statements)

References 27 publications

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“…sp., that show transitional characters towards Middle Norian faunas appear in sample D16A, still in the lower part of the Lacian 3, although they remain quite rare at this level. The slight forward shifting of the pit in front of the platform midlength, the prolongation of the posterior carina and the posterior prolongation of the keel are morphological developments that become dominant in the Alaunian 1 (Karádi, 2021). Notable is the asymmetry of the keel termination with the gradual loss of the secondary lobe, a feature that was also recognized by Kozur (1989a) and Orchard (2018).…”

Section: Discussionmentioning

confidence: 65%

New Advances in Biostratigraphy of the Lower/Middle Norian Transition: Conodonts of the Dovško Section, Slovenia

et al. 2021

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This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dovško Section in Slovenia, which represents the eastern part of the Slovenian Basin. The age of the section ranges from the Lacian 1 to the Alaunian 1. The Lacian part of the succession is predominantly characterized by the representatives of the genus Ancyrogondolella. Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition. This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament- dominated wackestone-packstone, and the formation of small neptunian dykes, which may reflect environmental perturbations and/or a change in basin geometry. The proliferation of the genera Epigondolella and Mockina is observed in the Alaunian part of the section, though the genus Ancyrogondolella is still present in this interval. Systematic description of the conodont taxa is provided, and seven new species and two new subspecies are established. The new advances will be of great value in further biostratigraphic studies, especially in areas without ammonoid faunas, and in the reconstruction of the paleogeography of the Slovenian Basin.

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Section: Discussionmentioning

confidence: 65%

New Advances in Biostratigraphy of the Lower/Middle Norian Transition: Conodonts of the Dovško Section, Slovenia

et al. 2021

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“…6, figs 1–7). Another bias is caused by gradual evolutionary trends that can happen in short timespans and affect not only intrageneric lineages (Orchard 1983; Karádi 2021) but even a single species. Such examples can be seen in the descriptions of the Carnian–Norian boundary species Kraussodontus peteri , Quadralella deflecta and Q. posteroexpansa provided by Orchard (2014), who used the platform length versus blade length ratio, the element size and carina length, and variance in the pit position to distinguish stratigraphically older and younger morphotypes within the species.…”

Section: Discussionmentioning

confidence: 99%

“…Visible in the lateral outline of the element. See Figure 2A and Karádi (2021, fig. 3) for examples.…”

Section: Methodsmentioning

confidence: 99%

Potential of closed contour analysis for species differentiation and holotype designation: a case study on lower Norian (Upper Triassic) conodonts

Virág

Karádi

2023

Palaeontology

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Geometric morphometric approaches become increasingly applied in the fields of biology and palaeontology. Taxonomy is a good example, where a long‐standing intention of scientists is to eliminate subjectivity as much as possible. In the case of biostratigraphically important conodont elements, the application of such methods is not widespread. Only a handful of studies attempted to deal with the morphological variance of conodont elements from this aspect. The detailed description of five lower Norian (Upper Triassic) taxa (Ancyrogondolella quadrata, A. rigoi, A. triangularis, A. uniformis and Metapolygnathus mazzai) is presented here based on landmarks and Fourier analysis of the P1 element and keel outlines. Both methods led to similar outcomes regarding taxonomic differentiation and exposing shape variability. Consensus shapes were generated to objectively reveal the typical contour shape of each taxon, which allowed their comparison with each other, and with the members of their respective sample population including the holotypes. The results demonstrated that the holotype of a taxon is generally not an average representative, but rather a peripheral form with well separable morphological characteristics. Ancyrogondolella quadrata and A. rigoi turned out to represent a morphological continuum with ample transitional forms between these two end‐members that may cause bias in their biostratigraphic applicability, however their combined shape variance seems to be too large for uniting them into a single species. Given the results that may be too subtle to realize based solely on qualitative observations, future taxonomic studies and type material designation could greatly benefit from the application of similar methodologies.

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“…Conodonts were reasonably diverse in much of the Late Triassic period and show tendencies toward (i) shortening of the platform, (ii) increasing ornaments on the platform and (iii) forward-shifting of the basal cavity (Mazza et al 2010(Mazza et al , 2012Kiliç et al 2015;Karádi, 2021).…”

Section: D Implications For Conodont Evolutionmentioning

confidence: 99%

The Ladinian–Carnian conodont fauna at Yize, Yunnan, southwestern China, with implications for conodont palaeoecology and palaeogeography

Zhang

Sun²

2023

Geol. Mag.

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Subdivisions of Ladinian–Carnian boundary beds and the lower Carnian strata in South China are challenging owing to a paucity of west Tethyan ammonoids. We investigated a conodont fauna in a continuous section at Yize in eastern Yunnan Province to provide a biostratigraphic solution. Five genera and 24 conodont species are recognized, and five conodont zones are established. The zones are, in ascending order, the Paragondolella inclinata Zone, the Quadralella polygnathiformis Zone, the Quadralella praelindae Zone, the Quadralella auriformis Zone and the Quadralella robusta Zone. The Ladinian–Carnian boundary is provisionally defined by the first occurrences of Quadralella polygnathiformis and Quadralella intermedia in the cherty limestone member of the Zhuganpo Formation. Regional correlations via conodont biostratigraphy indicate that the Zhuganpo Formation is probably diachronous, with a maximal range spanning the upper Ladinian to the lower Carnian. Amongst all common late Ladinian – early Carnian conodont genera, Paragondolella, Quadralella and Mazzaella are probably cosmopolitan. Budurovignathus was restricted to a few basins and probably preferred offshore or deep-water environments.

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Evolutionary trends of the genus Ancyrogondolella (Conodonta) and related taxa in the Norian (Late Triassic)

Cited by 13 publications

References 27 publications

New Advances in Biostratigraphy of the Lower/Middle Norian Transition: Conodonts of the Dovško Section, Slovenia

New Advances in Biostratigraphy of the Lower/Middle Norian Transition: Conodonts of the Dovško Section, Slovenia

Potential of closed contour analysis for species differentiation and holotype designation: a case study on lower Norian (Upper Triassic) conodonts

The Ladinian–Carnian conodont fauna at Yize, Yunnan, southwestern China, with implications for conodont palaeoecology and palaeogeography

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