The complete mitochondrial genome of Haustorioides koreanus Jo, 1988 (Crustacea: Amphipoda: Dogielinotidae).

The mitochondrial genome of a dogielinotid amphipod, Haustorioides koreanus, was completely sequenced for the first time. The total mitogenome length of H. koreanus was 14,839 bp with 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. The phylogenetic tree confirmed that H. koreanus belongs to the families Hyalellidae in the same clade and to the suborder Senticaudata within Amphipoda. This is the first record of the complete mitochondrial genome sequence of the family Dogielinotidae.

Integrative description of Diosaccus koreanus sp. nov. (Hexanauplia, Harpacticoida, Miraciidae) and integrative information on further Korean species.

A new species of Diosaccus Boeck, 1873 (Arthropoda, Hexanauplia, Harpacticoida) was recently discovered in Korean waters. The species was previously recognized as D. ezoensis Itô, 1974 in Korea but, here, is described as a new species, D. koreanus sp. nov., based on the following features: 1) second inner seta on exopod of fifth thoracopod apparently longest in female, 2) outer margin of distal endopodal segment of second thoracopod ornamented with long setules in male, 3) caudal seta VII located halfway from base of rami (vs. on anterior extremity in D. ezoensis), and 4) sixth thoracopod with three setae in female (vs. 2 setae in D. ezoensis). In addition, there is also a mitochondrial COI sequence difference of more than 19.93% with D. ezoensis registered in NCBI. A key to Diosaccus species of the world is also provided, and new morphological features and DNA sequences are presented for two other harpacticoid species, Parathalestris verrucosa Itô, 1970 and Peltidium quinquesetosum Song & Yun, 1999. In order to clearly identify harpacticoids at the species level, both morphological and DNA sequence characteristics should be considered.

The complete mitochondrial genome of Undinula vulgaris (Dana, 1849) (Crustacea: Calanoida: Calanidae).

The present study reports, for the first time, the complete mitochondrial genome (mitogenome) of Undinula vulgaris. The total mitogenome length of U. vulgaris was 15,303 bp with 13 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and 1 non-coding region. Phylogenetic analysis showed that U. vulgaris belonged to the same family. This is the second report of the complete mitogenome sequence of the family Calanidae.

Two new species of Leptopsyllus from Korea (Copepoda, Harpacticoida, Paramesochridae).

Two new species of Leptopsyllus are described from the subtidal zone of Korea. Both species were assigned to the subgenus Leptopsyllus (Leptopsyllus) T. Scott, 1894, based on following three characters: two-segmented rami of P1, absence of endopod on P2 and P3, and presence of one-segmented endopod of P4. L. (L.) pundius sp. n. is most closely related to L. (L.) punctatus Mielke, 1894, however clearly distinguishable from it based on mandibular exopod with two setae, shape of P6, and caudal seta III ornamented with spinules in the new species. L. (L.) koreanus sp. n. is clearly distinguishable from its congeners by the second segment of P1 endopod armed with one element, male baseoendopod of P5 with one seta, and one segmented endopod of mandibular palp. The world distribution and updated key to the species of the genus Leptopsyllus are provided.

Two new species of the genus Emertonia Wilson, 1932 from Korean waters (Copepoda, Harpacticoida, Paramesochridae).

Two new species of the genus Emertonia were found from the west coast of Korea. The first new species, E. koreanasp. n., is closely related to E. acutifurcata. However, the new species is clearly distinguished by the presence of two modified pinnate setae on the P5 baseoendopodal lobe. All body somites of the new species except for the last two urosomites have strongly developed hyaline frills forming quadrilateral lappets. The second new species, E. simplexsp. n., superficially resembles E. mielkei in the structure of antennary exopod (with five setae), and the shape of P5. However, this new species differs from its congener mainly by having a caudal ramus 3.5 times as long as width, and P1 enp-2 with two claw-like setae. In addition, a key to the worldwide species of Emertonia is provided.

Two new species of the genus Wellsopsyllus (Copepoda; Harpacticoida; Paramesochridae) from the Yellow Sea.

A study of benthic harpacticoids from the intertidal zone of Gosapo Beach, on the west (Yellow Sea) coast of Korea, resulted in the discovery of two species of Wellsopsyllus Kunz, 1981. The first new species, Wellsopsyllus (Wellsopsyllus) egregius sp. nov., was allocated to the nominotypical subgenus by a combination of three characters: 1) a 3-segmented P4 exopod, 2) 1-segmented P2-P3 endopods, and 3) a P1 endopod-2 with one apical seta. However, it can be clearly distinguished from its congeners by the following characters: 1) a caudal rami with two blunt setae and the seta VII located sub-distally, 2) a P2 and P3 endopod represented by a small blunt process, and 3) the semioval shape of P5. The second new species was placed in the subgenus Scottopsyllus Apostolov & Marinov, 1988 according to the 3-segmented exopod and 2-segmented endopod of P4. Wellsopsyllus (S.) koreanus sp. nov. exhibits a unique combination of characters: 1) a dimpled distal margin of the female P5 endopodal lobe armed with two subequal setae, 2) a caudal seta V consisting of a stout spine-like base with a long cylindrical seta-like portion arising subdistally, and 3) a distinct bundle of five long inner setules on the P1 basis. We present a summary of the characters of all species in the genus Wellsopsyllus and propose an updated key for their identification. 

A new genus (Copepoda, Harpacticoida, Laophontidae) from Jeju Island of Korea.

A survey on the harpacticoid copepods from an intertidal zone in Hyeopjae sandy beach, Jeju Island, Korea, resulted in the discovery of an unusual laophontid, Jejulaophontehyeopjaeensis sp. n., which cannot be placed in any extant genus within the family. To accommodate the species, a new genus of the family Laophontidae T. Scott, 1905 is proposed and fully described here. The new species is closely related to the lineage of the five primitive genera, Carraroenia McCormack, 2006, Coullia Hamond, 1973, Hemilaophonte Jakubisiak 1933, Psammoplatypus Lee & Huys, 1999, and Robustunguis Fiers, 1992 (the CCHPR-lineage) by the reduced P2 endopod, ovate shape of the female P5 exopod and sexual dimorphism in the P3 endopod. However, it displays discrepancies from the species of the CCHPR-lineage in the presence of an inner seta on P3 and P4 exp-2, four setae on P4 enp-2, and an inner seta on P3 and P4 enp-2 in the female. Furthermore, no other species within the family Laophontidae has three setae on P2 exp-3 and a seta on P2 enp-2 at the same time. The new species has sexual dimorphism in the antennule, genital segmentation and the legs from P2 to P5. The terminal seta on the second endopodal segment of P2 in the male is longer than that in the female. The endopod of P3 is 3-segmented and displays a short inner apophysis on the second segment in the male. The outer setae on the exopod of P3 and P4 are distinctly thicker and stronger in the male than in the female. Mitochondrial cytochrome oxidase subunit I (mtCOI) sequencing of the new species has been realized in order to be used in future phylogenetic analysis.

A new species of the genus Tegastes (Copepoda: Harpacticoida: Tegastidae) from hydrothermal vents in the Okinawa Trough.

We describe a new species, Tegastes okinawaensis, from 583-711 meter-deep hydrothermal vents in the Okinawa Trough, Japan. This species is clearly distinguishable from its congeners by four combined characters, namely 1) the last three abdominal somites are depressed inwardly towards the body, 2) there is sexual dimorphism in the number of setae of P3 and P4, 3) the male antennule is 9-segmented, with the 7th segment formed by incomplete fusion of two segments, and 4) the caudal rami are small with a distorted quadrangular shape. Additionally, the species is easily distinguishable from its congeners by the distal endopodal segment of P4, which is armed with six setae - this character has never been reported in previous descriptions of congeners. This report is the first of a species in the genus Tegastes living at ocean depths of greater than 580 m in the northwestern Pacific.