TY  - JOUR
A1  - Rasmussen, Jan Audun
A1  - Eriksson, Mats E.
A1  - Lindskog, Anders
T1  - Middle Ordovician Drepanoistodus (Vertebrata, Conodonta) from Baltica, with description of three new species
T2  - European journal of taxonomy
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.
T3  - European journal of taxonomy  : EJT - 774:106-134 
KW  - conodont
KW  - Drepanoistodus
KW  - new species
KW  - Ordovician
KW  - Baltica
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/61678
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-616782
SN  - 2118-9773
VL  - 2021
IS  - 774
SP  - 106
EP  - 134
PB  - Muséum National d'Histoire Naturelle
CY  - Paris
ER  -