Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species
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Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species. / Rasmussen, Jan Audun; Eriksson, Mats E.; Lindskog, Anders.
In: European Journal of Taxonomy, Vol. 774, 2021, p. 106-134.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species
AU - Rasmussen, Jan Audun
AU - Eriksson, Mats E.
AU - Lindskog, Anders
N1 - Publisher Copyright: © 2021, Museum National d'Histoire Naturelle. All rights reserved.
PY - 2021
Y1 - 2021
N2 - Drepanoistodus basiovalis (Sergeeva, 1963) is a common conodont species in Middle Ordovician strata of Baltica. For many years it has been widely accepted that the species encompasses a wide range of morphological plasticity. Hence, several different morphotypes that significantly deviate from the holotype have nonetheless been included in the broad species concept. In this study, we performed a detailed taxonomical study on 112 predominantly well-preserved specimens (geniculate elements) from the St. Petersburg region of Russia; 37 of these were selected for morphometric analyses together with 21 well-illustrated specimens from the published literature. The results demonstrate that, among the morphotypes that share some characteristics with D. basiovalis sensu lato, at least five species can be readily distinguished. Hence, three new species – Drepanoistodus iommii sp. nov., D. svendi sp. nov. and D. viirae sp. nov. – are here added to the previously known D. basiovalis and D. contractus (Lindström, 1955). In addition, some specimens were left under open nomenclature and assigned to Drepanoistodus aff. basiovalis and D. cf. suberectus (Branson & Mehl, 1933). In order to objectively compare the Drepanoistodus taxa and test the validity of the new species, we performed a Principal Component Analysis combined with non-parametric (PERMANOVA) tests based on 21 morphological characters.
AB - Drepanoistodus basiovalis (Sergeeva, 1963) is a common conodont species in Middle Ordovician strata of Baltica. For many years it has been widely accepted that the species encompasses a wide range of morphological plasticity. Hence, several different morphotypes that significantly deviate from the holotype have nonetheless been included in the broad species concept. In this study, we performed a detailed taxonomical study on 112 predominantly well-preserved specimens (geniculate elements) from the St. Petersburg region of Russia; 37 of these were selected for morphometric analyses together with 21 well-illustrated specimens from the published literature. The results demonstrate that, among the morphotypes that share some characteristics with D. basiovalis sensu lato, at least five species can be readily distinguished. Hence, three new species – Drepanoistodus iommii sp. nov., D. svendi sp. nov. and D. viirae sp. nov. – are here added to the previously known D. basiovalis and D. contractus (Lindström, 1955). In addition, some specimens were left under open nomenclature and assigned to Drepanoistodus aff. basiovalis and D. cf. suberectus (Branson & Mehl, 1933). In order to objectively compare the Drepanoistodus taxa and test the validity of the new species, we performed a Principal Component Analysis combined with non-parametric (PERMANOVA) tests based on 21 morphological characters.
KW - Baltica
KW - Conodont
KW - Drepanoistodus
KW - New species
KW - Ordovician
U2 - 10.5852/ejt.2021.774.1533
DO - 10.5852/ejt.2021.774.1533
M3 - Journal article
AN - SCOPUS:85117187350
VL - 774
SP - 106
EP - 134
JO - European Journal of Taxonomy
JF - European Journal of Taxonomy
SN - 2118-9773
ER -
ID: 282742363