The taxonomic status of Theragra finnmarchica Koefoed, 1956 (Teleostei: Gadidae): perspectives from morphological and molecular data
Abstract:The gadoid fishes Theragra finnmarchica from the coast of northern Norway and Theragra chalcogramma from the north-east Pacific could not be taxonomically discriminated by sequencing the mitochondrial cytochrome c oxidase I (COI) gene. However, the taxa differed in 10 of 42 non-osteological and in four of 17 osteological characters. Ontogenetic changes were found for 16 of the examined non-osteological characters. Five taxon-specific characters, unaffected by ontogenetic scaling, were examined by discriminant analysis. A 100% correct classification was obtained from a discriminant function based on number of pyloric caeca and number of gill rakers on the upper part of the gill arch. However, all examined characters overlapped between the two taxa, except the number of pyloric caeca. On the basis of their genetic similarity and slight morphological differences, T. finnmarchica should be considered a junior synonym of T. chalcogramma.
Document Type: Regular Paper
Affiliations: 1: Bergen Museum, University of Bergen, Muséplass 3, N-5007 Bergen, Norway 2: Department of Aquatic BioSciences, Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway
Publication date: 2008-10-01