Position of neck banded blenny Leptostichaeus pumilus (Perciformes: Zoarcoidei) in the system of the suborder Zoarcoidei as inferred from molecular genetic data

Molecular genetic study of genetic variations within COI, cytochrome b, and 16S rRNA of mitochondrial DNA in neck banded blenny Leptostichaeus pumilus, which was earlier assigned to the family Stichaeidae, indicates that the species is most close to a group combining the families Zoarcidae, Neozoarcidae, and Anarhichadidae. Significant genetic differences between neck banded blenny and the family Stichaeidae correspond to the level of divergence between other families of the suborder Zoarcoidei (Zaproridae, Ptilichthyidae, Pholidae, Cryptacanthodidae, and Bathymasteridae).     

Position of the genera <Emphasis Type=Italic>Lycenchelys</Emphasis> Gill and <Emphasis Type=Italic>Lycodapus</Emphasis> Gilbert in the family zoarcidae (Perciformes: Zoarcoidei) inferred from molecular genetic analysis

Sequence variation of the mitochondrial COI, cytochrome b, and 16S RNA genes, as well as nuclear RNF213 gene was examined in the genera Lycenchelys and Lycodapus with the purpose of determination of their positions in the system of the family Zoarcidae. It was demonstrated that the genus Lycodapus was considerably closer to the generic group of Lycogramminae (Lycogrammoides, Bothrocara, Allolepis, Bothrocarhichthys) than the genus Lycenchelys. However, on the phylogenetic trees both of these genera were located in the clade of the subfamily Lycodinae. Genetic heterogeneity of the genus Lycenchelys, represented by two species groups differing in distribution patterns (northeastern Pacific and Antarctic) and showing more profound differences than the genera of subfamily Lycodinae, was demonstrated.     

Phylogenetic relations in the family pholidae (Perciformes: Zoarcoidei) based on genetic and morphological data

Molecular-genetic study of Pholidae of the suborder Zoarcoidei was first performed. Analysis of variation of genes of COI, cytochrome b, and 16S rRNA of mitochondrial DNA indicates different phylogenetic isolation of the family taxa. The groundlessness of separating subgenera (or genera) Enedrias and Allopholis and the rightfulness of including them in the composition of the genus Pholis are shown. Genetic close relation of the genera Pholis and Rhodymenichthys and their differences from the genus Apodichthys are established. The obtained results agree with the data of Makushok (1958) who separated in the composition of the family two subfamilies—Pholinae (with genera Pholis and Rhodymenichthys) and Apodichthyinae (with the genera Apodichthys, Xererpes, and Ulvicola). A key to species, genera, and subfamilies of gunnels of the northern part of the Pacific Ocean is provided.     

Relationships of eelpouts of genus Zoarces (Zoarcidae, Pisces) inferred from molecular genetic and morphological data

Molecular genetic and morphological analysis of eelpouts of the genus Zoarces was carried out. Based on the mitochondrial DNA sequence variation, haplotypes of notched-fin eelpout, Z. elogatus, more closely related Fedorov eelpout, Z. fedorovi, and common eelpout, Z. viviparus, as well as of Andriyashev eelpout, Z. andriashevi, were grouped in one macrocluster. Haplotypes of American eelpout, Z. americanus, and blotched eelpout, Z. gillii, clustered separately from other species. The genetic differences between Z. gillii and the other eelpout species were very high for within-genus comparisons, constituting 7.62%. Species divergence in terms of morphological characters was generally consistent with molecular genetic data and confirmed distinct isolation of American eelpout, and especially of blotched eelpout.     

Position of the genus Azygopterus (Stichaeidae,Perciformes) in the system of the suborder Zoarcoidei as inferred from sequence variation of mitochondrial and nuclear genes

Analysis of sequence variation in the mitochondrial and nuclear genes in Azygopterus corallinus showed that this species was genetically close to the group uniting the representatives of the families Zoarcidae, Neozoarcidae, and Anarhichadidae. The considerable genetic differences between A. corallinus and the members of the family Stichaedae, to which it was assigned earlier, are consistent with the divergence estimates between the other families of the suborder Zoarcoidei (Zaproridae, Ptilichthyidae, Pholidae, Cryptacanthodidae, Bathymasteridae).     

Osteology of the Graveldiver Scytalina cerdale (Perciformes: Zoarcoidei: Scytalinidae)

The Graveldiver, Scytalina cerdale, is a small, poorly known burrowing fish from the intertidal and subtidal zones of the west coast of North America, ranging from south‐central California to Alaska. This is the sole member of the family Scytalinidae, which is included in the Zoarcoidei. Although it was described over 120 years ago, it is rare in natural history collections and its anatomy is only imperfectly known. This article describes and illustrates the skeletal anatomy of S. cerdale based on newly prepared cleared and stained specimens. Many points of its anatomy are clarified or corrected (e.g., presence of the intercalars and ribs, in contrast to their reported absence) or described for the first time (e.g., structure of its gill‐arches). Previous hypotheses of its systematic placement within the Zoarcoidei are discussed. On the basis of preliminary comparisons, S. cerdale may have phylogenetic affinity with at least some members of the family Stichaeidae (e.g., Xiphister). However, further study is needed on the anatomy and inter‐relationships of the families of the Zoarcoidei before any conclusions can be made. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

Description of two new genera, Santelmoa and Bentartia and two new species of Zoarcidae (Teleostei, Perciformes) from the Southern Ocean

Two new genera of lycodine zoarcid fish, Santelmoa and Bentartia, and two new species, Santelmoa carmenae and Bentartia cinerea, are described from 13 specimens collected from the Gerlache Strait, Southern Ocean, at 1,056-m depth. Santelmoa can be distinguished from all other lycodine genera by the combination of the following characters: anterior portion of frontals fused; scapular foramen open; ceratohyal–epihyal articulation interdigitating; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar reaching the prootic; parasphenoid wing well developed; palatal arch well developed; posterior hyomandibular ramus short; post-temporal ventral ramus well developed; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. Bentartia differs from the remaining lycodine genera by the following combination of characters: basioccipital and exoccipitals fused; supraoccipital–exoccipital articulation broadly contacting; ceratohyal–epihyal articulation interdigitating; post-temporal ventral ramus weak; two posterior nasal pores; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar set posteriorly; palatal arch well developed; posterior hyomandibular ramus not elongate; parasphenoid wing high; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. The relationships of the two new genera are discussed.     

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

To determine the taxonomic position of wrymouths of the family Cryptacanthodidae in the system of the suborder Zoarcoidei, a study on molecular genetics and comparative morphology of Cryptacanthodes bergi from Peter the Great Bay (Sea of Japan) is conducted. Based on molecular genetic analysis using the genes of nuclear and mitochondrial DNA, Cryptacanthodes bergi is substantially similar to the representatives of the superfamily Stichaeoidae. Thus, the opinion of Makushok on a phylogenetically distinct position of wrymouths in relation to snake blennies and related families is not supported. The anatomical features of skull structure support the data of molecular genetics. The directions and time of distribution of wrymouths in the northwest Atlantic through the channel in the area of the Isthmus of Panama in approximately the late Miocene are discussed.     

Relationships among several species of the subfamily Gymnelinae (Zoarcidae) inferred from mitochondrial DNA sequence analysis

Nucleotide sequences of the mtDNA COI and cytochrome b genes were determined in Magadanichthys skopetsi, a member of the new monotypic genus Magadanichthys, endemic to the northern coast of the Sea of Okhotsk. Comparison of this species with other representatives of the subfamily Gymnelinae (family Zoarcidae) revealed high genetic similarity of M. skopetsi to Hadropareia middendorffii and considerable differences between these species and Gymnelopsis ochotensis.     

Brain and sensory organ morphology in Antarctic eelpouts (Perciformes: Zoarcidae: Lycodinae)

Eelpouts of the family Zoarcidae comprise a monophyletic group of marine fishes with a worldwide distribution. Centers of high zoarcid diversity occur in the North Atlantic and North Pacific, with important radiations into the Arctic, along southern South America, and into the Southern Ocean around Antarctica. Along with snailfishes (Liparidae), zoarcids form an important component of the non-notothenioid fauna in the subzero shelf waters of Antarctica. We document the anatomy and histology of the brains, cranial nerves, olfactory apparatus, cephalic lateral lines, taste buds, and retinas of three Antarctic zoarcid species, living at depths of 310-939 m, representing three of the nine genera from this region. The primary emphasis is on Ophthalmolycus amberensis, and we provide a detailed drawing of the brain and cranial nerves of this species. Although this brain reflects general perciform neural morphology, it exhibits a reduction of the (optic) tecta and the eminentia granulares and crista cerebellares of the lateral line system. Interspecific differences among the three species are slight. The olfactory rosette consists of three to four lamellae and the nasal sac, contrary to the claim of Fanta et al. ([2001] Antarct Rec, Natl Inst Polar Res, Tokyo 45:27-42), is not in communication with the cephalic lateral line system. Primary olfactory neurons are abundant and converge on branches of the olfactory nerve. Numerous taste buds are located in the lips. All three species lack an ocular choroid rete and have relatively thin retinas with a low cell density and a single bank of rods as the only type of photoreceptor. Neural diversification among Antarctic zoarcids has not involved the evolution of sensory specialists; brain and sensory organ morphologies do not approach the condition seen in primary deep-sea fishes, or even that of some sympatric non-perciform secondary deep-sea fishes, including liparids and muraenolepidids (eel cods). There may be phylogenetic constraints on brain morphology in perciforms such that we do not see extreme specialization in sensory and neural systems for deep habitats. We suggest that the brains and sensory organs of Antarctic zoarcids reflect habitation of 500-2,000-m depths and likely reflect morphologies seen in zoarcids living on continental slopes elsewhere in the world. This balance among the sensory modalities makes zoarcids relatively generalized among secondary deep-sea fishes and may be one of the reasons this opportunistic and adaptable group has been successful in colonizing a variety of emergent and ephemeral habitats.     

Timeline of the evolution of eelpouts from the suborder Zoarcoidei (Perciformes) based on DNA variability

Based on the analysis of variability of mitochondrial and nuclear DNA and calibration of the molecular clock using the paleontological data, the divergence time of the eelpouts is assessed. The temporal frames of the evolution of the suborder Zoarcoidei are restricted to the Late Oligocene and the middle of the Late Miocene, within a diapason of approximately 12 Ma. The families Bathymasteridae and Cebidichthyidae were the first to separate from the common ancestor, 14.7–22.5 and 13.1–19.1 Ma, respectively. The differentiation of other families occurred between the Middle and the Late Miocene approximately 10–15 Ma. The period from the Late Miocene to the Mid-Pliocene (3.6–7.8 Ma), most likely, was the time of the appearance and distribution of the present species of the suborder. Assessment of the DNA divergence rate in the eelpouts conducted in this study is in accordance with known evolutionary scenarios and with key steps of geological development of the World Ocean.     

Genus Leptostichaeus and its position in the taxonomy of fishes (Perciformes: Zoarcoidei, Stichaeidae)

Up to the present, the genus Leptostichaeus has been considered as belonging to subfamily Lumpeninae. A series of characters was analyzed for family and subfamily diagnostics within the group Stichaeidae. It was found that, in combination of all examined characters, the genus Leptostichaeus is either similar to Azygopterus or occupies an intermediate position between the latter and other members of the family Stichaeidae. The genus Leptostichaeus is transferred into the group Azygopterinae, which is revalidated as a subfamily within the family Stichaeidae.     

Position of enigmatic miniature trichomycterid catfishes inferred from molecular data (Siluriformes)

Trichomycteridae is a well‐corroborated catfish family that comprises about 300 valid species distributed in eight subfamilies. The phyletic status of the Trichomycterinae is uncertain, with different hypothesis regarding the position of the miniaturized Trichomycterus hasemani group. This group comprises four valid species, and neither its monophyly nor its positioning among the Trichomycteridae was tested in a phylogenetic framework. Bayesian Inference and Maximum Likelihood analyses of a molecular data set comprising the mitochondrial genes 12S and 16S and the nuclear genes H3, MYH6 and RAG2 (2983 bp) for 26 taxa highly supported the miniature catfish T. hasemani group as monophyletic and sister to the Tridentinae, consequently recognized as a new genus of this subfamily. Potamoglanis gen. nov. is diagnosed by seven character states: an angle of 35–40° between the main longitudinal axis of the head and the main axis of the autopalatine; thin tubular shape of the second ceratobranchial; presence of six or seven anal‐fin rays; eyes dorsally placed on head; opercular and interopercular odontodes patches not juxtaposed; absence of a distal process on the hyomandibula and presence of a long process on the anterior region of the hyomandibula. Potamoglanis gen. nov is similar to the Tridentinae genera by the presence of a wide cranial fontanelle; presence of a short ventral process in the opercular bone and by the origin of the dorsal fin placed in a vertical through the anal‐fin origin.     

Ericandersonia sagamia, a new genus and species of deep-water eelpouts (Perciformes: Zoarcidae) from Japan

A new genus and species of deep-water zoarcid fish, Ericandersonia sagamia, is described on the basis of four specimens collected from Sagami Bay, Japan, at depths of 880–930 m. This species is placed in the subfamily Gymnelinae and is distinguished from all genera of gymnelines by the following characters: pseudosubmental crest present; frontals partially fused dorsally; parietals meeting in midline; pelvic fins absent; ventral ramus of posttemporal weak; postorbital head pores 5; pectoral-fin rays 14. The phylogenetic analysis (based on 42 morphological characters) indicates that its position is outside the highly modified (= advanced) genera Seleniolycus, Melanostigma, Puzanovia, Nalbantichthys, Opaeophacus, and Andriashevia.     

Specific features of distribution and ecology of Lycenchelys fedorovi (Zoarcidae) in Pacific waters off the northern Kuril Islands

On the basis of material for 1993–2002, data are provided on occurrence, spatial-bathymetric distribution, and size composition of Lycenchelys fedorovi, as well as on species that occur simultaneously with it in catches in Pacific waters off the northern Kuril Islands. This relatively scarce, medium-sized representative of the family Zoarcidae (maximum length of 42 cm, body weight 200 g) during the period of studies occurred only at the site to the south of the Fourth Kuril Strait in the range of depths 220–775 m at the near-bottom temperature of 1.6–4.2°C. The dependence between the depth of catch and sizes of L. fedorovi was analyzed. It was shown that the size of its catches in Pacific waters off the northern Kuril Islands is subjected to some interannual, seasonal, and diurnal dynamics.     

On the interrelationships of the genera of creediidae (Perciformes: Trachinoidei)

An osteological study of representatives of the seven genera of creediids supports the view that the family is monophyletic. New diagnostic characters include the form of the pelvis, mesopterygoid, and ectopterygoid. Characters are given which distinguish members of Creediidae from other fishes. Three lineages of creediids are recognized on the basis of osteological and external characters, withSchizochirus insolens, the least derived and the most distinctive species, comprising the first lineage, the species ofCreedia the second, and those ofLinmichthys, Tewara,Crystallodytes, Chalixodytes, andApodocreedia the third.     

On the systematic position of the genus Petroschmidtia Taranetz et Andriashev, 1934 (Perciformes: Zoarcidae)

Following a comparative analysis of the morphological characters of the representatives of the genera Petroschmidtia and Lycodes, some previously proposed diagnostic characters of Petroschmidtia are confirmed and ascertained and several additional characters are suggested. The conclusion on the taxonomic validity of the genus Petroschmidtia is confirmed. Petroschmidtia differs from Lycodes in the following features: teeth and tooth plates on the vomer and palatinum are lacking; bone fontanels of the supraorbital canal on the frontale are lacking; the vomer is shortened; the ethmoidalia lateralia are narrowed, bearing a pocketlike cavity inside the lateral lobes; the fan-like expanded outgrowth of the supraoccipitale is short, blunt; the dentale is shortened; the radialia are dorsoventrally flattened, the lowest of which is the largest. The genus Petroschmidtia is assumed to be morphologically more closely related to Lycodes than any other of the Lycodinae.     

Relationships and position of the taxa of the subfamily Xiphisterinae in the system of the suborder Zoarcoidei (Perciformes)

Analysis of the nucleotide sequences of mitochondrial and nuclear DNA genes was used to examine the relationships and position of the subfamily Xiphisterinae in the system of the suborder Zoarcoidei. This study showed the genetic heterogeneity of Xiphisterinae and the propriety of its division into two subfamilies: Xiphisterinae with the genera Xiphister and Phytichthys and Cebidichthyinae with the genera Cebidichthys, Dictyosoma, Esselenichthys, and Nivchia. The genetic differences between the two subfamilies were not less, but in some cases even greater than the differences between families within the suborder; therefore, they should be raised to the rank of a family, Xiphisteridae and Cebidichthyidae, and classified not within the superfamily Stichaeoidae but rather as independent taxa of the suborder Zoarcoidei.     

Relationships of eelpouts of the genus <Emphasis Type="Italic">Zoarces</Emphasis> (Zoarcidae,Pisces) inferred from molecular genetic and morphological data

Abstract-Molecular genetic and morphological analysis of eelpouts of the genus Zoarces was carried out. Based on the mitochondrial DNA sequence variation, haplotypes of notched-fin eelpout, Z. elogatus, more closely related Fedorov eelpout, Z. fedorovi, and common eelpout, Z. viviparus, as well as of Andriyashev eelpout, Z. andriashevi, were grouped in one macrocluster. Haplotypes of American eelpout, Z. americanus, and blotched eelpout, Z. gillii, clustered separately from other species. The genetic differences between Z. gillii and the other eelpout species were very high for within-genus comparisons, constituting 7.62%. Species divergence in terms of morphological characters was generally consistent with molecular genetic data and confirmed distinct isolation of American eelpout, and especially of blotched eelpout.