Relationships and position of wrymouths of the family cryptacanthodidae in the system of the suborder Zoarcoidei (Pisces, Perciformes)

Osteology and ontogeny of the wrymouths, genusCryptacanthodes(Cottiformes:Zoarcoidei:Cryptacanthodidae)

“…He, however, cited clear morphological differences between these species and opted against synonymizing them (e.g., C. aleutensis almost always lacked palatine teeth, whereas C. bergi always had one or two: means in his study being 0.03 vs. 1.4 palatine teeth, respectively). The taxonomic separation of C. aleutensis and C. bergi recently has been supported by genetic evidence, with the two species having 6.3% divergence in COI, which is similar to the difference, for example, between C. bergi and C. giganteus (Radchenko et al, 2011). Nawojchik (1986) concluded that C. maculatus was sister to C. bergi 1 C. aleutensis, with C. giganteus forming the sister species of all other cryptacanthodids.…”

“…Although they only included C. giganteus in their molecular data set, Radchenko et al () discussed at length the relationships of the four species, and considered C. maculatus and C. giganteus to be closely related, and these two species together to form the sister‐group of C. bergi + C. aleutensis . This interpretation was based solely on their large size and overall similarity (“These species differ from each other in only the presence of scales on the body of representative of [ C. giganteus ]… and they are similar based on other characters;” Radchenko et al, :497). In fact, all cryptacanthodids are similar in virtually all morphological characters presented by these authors (their Table 3), with the exception of number of dorsal‐fin spines (73–77 in C. maculatus and C. giganteus , vs. 60–70 in C. aleutensis and 66–69 in C. bergi ).…”

“…As Nawojchik (:61–62) stated “The status of C. maculatus as the only Atlantic wrymouth raises obvious zoogeographic questions. For example, if the cryptacanthodids had a Pacific origin, which seems highly likely…how did C. maculatus reach the Atlantic?” Radchenko et al (:497), who considered C. giganteus and C. maculatus to be sister species, stated “the occurrence of a single ancestral form can be suggested. This form entered the northwest Atlantic, most likely, before the divergence of the group C. aleutensis + C. bergi from C. giganteus .” This supposition was based on a rough molecular clock calculated by these authors, which suggested a divergence time of 6.1–7.6 million years for the cryptacanthodid species, and 9.3–13.7 million years for the family itself.…”

Position of Krusensterniella genus (Gymnelinae, Zoarcidae) in the system of Zoarcidae fish family according to molecular genetic data

“…The aim of the study was to determine the Krusen sterniella genus position in the Zoarcidae fish family based on molecular genetic study. This approach dem onstrated a high effectiveness in solving similar prob lems on the development of systematics of other taxa from the Zoarcoidei suborder (Radchenko et al, 2008(Radchenko et al, , 2010a(Radchenko et al, , 2010b(Radchenko et al, , 2011(Radchenko et al, , 2012Chereshnev et al, 2009).…”

Osteology of the prowfish, Zaprora silenus (Cottiformes: Zoarcoidei: Zaproridae)

“…With slightly different taxon sampling, Radchenko et al () recovered Zaprora as the sister‐group of a clade including lumpenine stichaeids, Ptilichthys , pholids, neozoarcines, and other zoarcids (albeit weakly supported; 71% posterior probability). In a subsequent Bayesian analysis of the similar mitochondrial data, Radchenko et al () again found a weakly supported sister‐group relationship between Zaprora and some of the lumpenine stichaeids ( Acantholumpenus and Leptoclinus ), with Cryptacanthodes emerging as a well‐supported sister‐group of this clade. However, much of this resolution was lost in their analysis of a nuclear gene ( RNF213 ).…”