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We present a genome assembly from an individual Eutrigla gurnardus (the grey gurnard; Chordata; Actinopteri; Scorpaeniformes; Triglidae). The genome sequence is 680.5 megabases in span. Most of the assembly is scaffolded into 24 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.51 kilobases in length.

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Scorpaena neglecta (Temminck and Schlegel, 1843) is a marine fish, in the family Scorpaenidae, order Scorpaeniformes, class Actinopterygii of the phylum Chordata. The first species of Scorpaena with a complete mitochondrial genome is described in the present study. The circular mitochondrial genome of S. neglecta has 17,202 bp with 54.75% A + T content and encodes 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), and two ribosomal RNA (rRNA). The phylogenetic tree indicates S. neglecta clustered into one branch and is closely related to other Scorpaenidae species. The mitochondrial genome structure and gene content of S. neglecta will support the study of evolution and phylogenetic relationships among Scorpaenidae species.

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BACKGROUND: The family Plectanocotylidae includes parasites of the gills of marine fish; although nine genera and about 20 species have been described, almost no molecular information is available. Putting aside Plectanocotyle elliptica Diesing, 1850, supposedly a parasite of the white perch Morone americana, never found again since its original description, two species were valid within Plectanocotyle Diesing, 1850 before this work: Plectanocotyle gurnardi (Van Beneden & Hesse, 1863) Llewellyn, 1941 and Plectanocotyle major Boudaya, Neifar & Euzet, 2006. METHODS: In this paper, we describe the third species of the genus Plectanocotyle and perform a comparative morphological and molecular analysis of the three species and of Triglicola obscura (Euzet & Suriano, 1974) Mamaev, 1976. Host fishes were also barcoded (COI) for confirmation of host identifications. RESULTS: Plectanocotyle lastovizae n. sp. is described from the gills of the streaked gurnard Chelidonichthys lastoviza collected off Algeria. The species is compared with specimens of Plectanocotyle cf. gurnardi (from C. lastoviza) from the same locality and P. major and T. obscura (both from the longfin gurnard C. obscurus). Molecules from Plectanocotyle cf. gurnardi could not be compared with P. gurnardi from the type-host and type-locality and we kept the status of the Mediterranean specimens as pending. Algeria is a new geographic record for P. major and T. obscura. Plectanocotyle lastovizae n. sp. is distinguished from the other species found in the Mediterranean by the measurements of clamps, number of testes, and COI sequences, with notable divergence (7.8-11.8%) from the other two species of the genus. DISCUSSION: We briefly present a list of currently known members of the family Plectanocotylidae, their biology and their hosts.

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During pelagic video transects off Santo Antão, Cabo Verde, we encountered the midwater scorpionfish Ectreposebastes imus in midwater between 300 and 800 m over a bottom depth of about 1000 m. The fish were typically positioned vertically with their heads pointing upwards. These first midwater observations of E. imus suggest migratory (potentially feeding) behaviour into the pelagic realm and hence a possible role of this species in the trophic coupling between the pelagic and benthic habitats in the deep seas of Cabo Verde and elsewhere in its global distribution.

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In this study, the complete mitochondrial genome of Cottiusculus nihonkaiensis was presented, and we also discussed its mitochondrial characteristics. The full length of the mitochondrial genome was 16,612 bp, containing 13 protein-coding genes (PCGs), two ribosomal RNAs (12S and 16S), 22 transfer RNA genes (tRNA), one non-coding control region (CR) and one origin of replication on the light-strand. Overall base composition of the complete mitochondrial DNA was 26.4% A, 17.4% G, 31.5% C, 24.7% T. The phylogenetic tree suggested that C. nihonkaiensis shared the most recent common ancestor with Gymnocanthus herzensteini, Gymnocanthus intermedius and Gymnocanthus tricuspis.

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Histological examination of Atka mackerel ovotestes reveals the possibility of intersexuality. Individuals with bisexual gonads have been caught in the North Pacific near the south-east coast of the Kamchatka peninsula. While intersex appeared to be normal females with developing ovaries, histological analysis showed the presence of both female and male tissue in the same gonad. Specifically, primary growth, cortical alveolar and primary vitellogenic oocytes were located among spermatogonia cysts. The prevalence of intersexuality in the population was less than 0.1%.

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The checklist by Robertson et al. (2017) of fishes from the tropical eastern Pacific included information on three members of the family Triglidae: Bellator loxias (Jordan, 1897), Prionotus ruscarius and P. stephanophrys Lockington, 1881. Unfortunately, the identification of four specimens as P. ruscarius is incorrect, as they are Bellator gymnostethus. We thank Benjamin Victor for bringing these misidentifications to our notice through his work with mtDNA sequence data from the Barcode of Life Database (BOLD: http://www.boldsystems.org). The photographs of the four specimens on the BOLD website clearly depict a Bellator species rather than a Prionotus. However, the photograph in the 2017 paper (Figure 75, page 78), is correctly identified and labelled as P. ruscarius, and this species was collected on the cruise of the Miguel Oliver discussed in Robertson et al. (2017), see Benavides Moreno et al. (2019). This correction brings the number of triglids collected on that cruise to four species.

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Occasional examinations of some marine fishes in Japan revealed, in addition to other parasites, the following eight species of philometrid nematodes (Philometridae) (all females only): Philometra kidakoi sp. n. from the ovary of Gymnothorax kidako (Temminck et Schlegel) (Muraenidae); Philometra pinnicola (Yamaguti, 1935) from the operculum of Epinephelus akaara (Temminck et Schlegel) (Serranidae); Philometra sebastisci Yamaguti, 1941 from the ovary of Sebastes cheni Barsukov (Scorpaenidae) (new host); Philometra madai Quiazon, Yoshinaga et Ogawa, 2008 from the ovary of Acanthopagrus schlegelii (Bleeker) (Sparidae) (new host); Philometra isaki Quiazon, Yoshinaga et Ogawa, 2008 from the ovary of Parapristipoma trilineatum (Thunberg) (Haemulidae); Philometra sp. from the ovary of Synanceia verrucosa Bloch et Schneider (Synanceiidae); Congerinema japonicum gen. et sp. n. from the subcutaneous tissue of Conger myriaster (Brevoort) (Congridae); and Clavinema mariae (Layman, 1930) from the operculum of Acentrogobius pflaumii (Bleeker) (Gobiidae). Specimens of all species are described based on light and scanning electron microscopical examinations. Philometra kidakoi sp. n. is the first gonad-infecting philometrid from the Muraenidae. The new monotypic genus Congerinema gen. n. is characterised by the unique net-like cuticular ornamentation on the female body. Clavinema mariae is considered to be a complex of several cryptic species and a need of the discovery of conspecific males is stressed (this also concerns other philometrid species with unknown males). At present, the fauna of philometrid nematodes parasitising marine fishes in Japanese waters is represented by 22 nominal species belonging to four genera.

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Complete mitochondrial genomes (mitogenomes) are important molecular markers for understanding the phylogenetics of various species. Although recent studies on the mitogenomes of the Scorpaeniformes species have been greatly advanced, information regarding molecular studies and the taxonomic localization of Platycephalidae is still sparse. To further analyze the phylogeny of Platycephalidae, we sequenced the complete mitogenome of Cociella crocodilus of the Platycephalidae family within Scorpaeniformes for the first time. The mitogenome was 17,314 bp in length, contained two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs), and two typical noncoding control regions (the control region (CR) and origin of the light strand (OL)). All PCGs used standard initiation codons ATG, apart from cox1. The majority of the tRNA genes could be folded into cloverleaf secondary structures, whereas the secondary structure of tRNASer (AGN) lacked a dihydrouridine (DHU) stem. The CR contained several conserved sequence blocks (CSBs) and eight tandem repeats. In addition, the phylogenetic relationship based on the concatenated nucleotides sequences of 13 PCGs indicated that the Platycephalidae species are relatively basal in the phylogenetic relationships of Scorpaeniformes. Our results may not only advance the origin and the evolution of Scorpaeniformes, but also provide information for the genetic evolution and taxonomy of the teleostean species.

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Here, we report the complete mitochondrial genomes of the Sculpins species Gymnocanthus intermedius and Gymnocanthus herzensteini. The mitogenomes were determined to be 16,639 bp for G. intermedius and 16,691 bp for G. herzensteini. The mitogenomes comprised 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a non-coding region. We then used the mitogenome data to construct a phylogenetic tree for these two species and an additional three species within the order Scorpaeniformes.

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We collected specimens of Microcotyle spp. from two species of scorpaeniform fishes off Algeria, namely Scorpaena notata and Helicolenus dactylopterus. The identification of both fishes was confirmed by molecular barcoding of the COI gene. Sequences of COI gene were also obtained for both parasite species. The species from S. notata is described as Microcotyle algeriensis n. sp., on the basis of morphological differences from other species (number of clamps, number of spines in genital atrium, number of testes). Its COI sequence differs from M. sebastis Goto, 1894 (from Sebastes schlegeli from a fish farm in South Korea) by 14.6%. The species from H. dactylopterus is distinct from M. algeriensis on the basis of morphology (number of clamps, number of spines in genital atrium) and COI sequence (4.5% divergence) and is also distinct from M. sebastis in its COI sequence (12.3%). We refrained from describing it as new because M. sebastis, a species originally described from scorpaeniform fishes off Japan, has been recorded in various hosts in the North and South Pacific, Atlantic and Mediterranean (for the latter, in the same host, H. dactylopterus). We believe that correct specific assignment of species of Microcotyle from scorpaeniform fishes needs a detailed morphological and molecular study of representatives from various locations and hosts.

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Phylogenetic relationships among members of the New World searobin genera Bellator and Prionotus (Family Triglidae, Subfamily Prionotinae) and among other searobins in the families Triglidae and Peristediidae were investigated using both mitochondrial and nuclear DNA sequences. Phylogenetic hypotheses derived from maximum likelihood and Bayesian methodologies supported a monophyletic Prionotinae that included four well resolved clades of uncertain relationship; three contained species in the genus Prionotus and one contained species in the genus Bellator. Bellator was always recovered within the genus Prionotus, a result supported by post hoc model testing. Two nominal species of Prionotus (P. alatus and P. paralatus) were not recovered as exclusive lineages, suggesting the two may comprise a single species. Phylogenetic hypotheses also supported a monophyletic Triglidae but only if armored searobins (Family Peristediidae) were included. A robust morphological assessment is needed to further characterize relationships and suggest classification of clades within Prionotinae; for the time being we recommend that Bellator be considered a synonym of Prionotus. Relationships between armored searobins (Family Peristediidae) and searobins (Family Triglidae) and relationships within Triglidae also warrant further study.

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The complete mitochondrial genome of the devil firefish Pterois miles (Bennett, 1828) was obtained using next generation sequencing approaches. The genome sequence was comprised of 16,497 bp exhibiting the standard vertebrate mitochondrial gene arrangement. Regions of gene overlap, tRNA lengths, as well as start and stop codons were similar to those observed in closely related families (i.e. Sebastidae, Peristediidae). Phylogenetic reconstructions support the polyphyly of Scorpaeniformes, and confirm the close relationship of Scorpaenidae and Sebastidae.

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Despite recent progress on the higher-level relationships of the Cottoidei and its familial components, phylogenetic conflict and uncertainty remain within the Cottoidea. We analyzed a dataset composed of 4518 molecular (mitochondrial 12S, tRNA-Val, 16S, and cytochrome b and nuclear TMO-4c4, Histone H3, and 28S) and 72 morphological characters for 69 terminals to address cottoid intrarelationships. The resulting well-resolved phylogeny was used to produce a revised taxonomy that is consistent with the available molecular and morphological data and recognizes six families: Agonidae, Cottidae, Jordaniidae, Psychrolutidae, Rhamphocottidae, and Scorpaenichthyidae. The traditional Agonidae was expanded to include traditional hemitripterids and Hemilepidotus. The traditional Cottidae was restricted to Leptocottus, Trachidermus, and the riverine, lacustrine, and Lake Baikal freshwater cottoids. Jordaniidae (Jordania and Paricelinus) was separated from the traditional cottids; Psychrolutidae was expanded from the traditional grouping to include nearly all traditional marine cottids and the single species of bathylutichthyid. Rhamphocottidae was expanded to include the traditional ereuniids, and Scorpaenichthyidae separated Scorpaenichthys from the traditional cottids. The importance of early-life-history characters to the resulting phylogeny and taxonomy were highlighted.

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