The ultrastructure of resurrection: Post-diapause development in an Antarctic freshwater copepod.

The copepod, Boeckella poppei, is broadly distributed in Antarctic and subantarctic maritime lakes threatened by climate change and anthropogenic chemicals. Unfortunately, comparatively little is known about freshwater zooplankton in lakes influenced by the Southern Ocean. In order to predict the impact of climate change and chemicals on freshwater species like B. poppei, it is necessary to understand the nature of their most resilient life stages. Embryos of B. poppei survive up to two centuries in a resilient dormant state, but no published studies evaluate the encapsulating wall that protects theses embryos or their development after dormancy. This study fills that knowledge gap by using microscopy to examine development and the encapsulating wall in B. poppei embryos from Antarctica. The encapsulating wall of B. poppei is comprised of three layers that appear to be conserved among crustacean zooplankton, but emergence and hatching are uniquely delayed until the nauplius is fully formed in this species. Diapause embryos in Antarctic sediments appear to be in a partially syncytial mid-gastrula stage. The number of nuclei quadruples between the end of diapause and hatching. Approximately 75% of yolk platelets are completely consumed during the same time period. However, some yolk platelets are left completely intact at the time of hatching. Preservation of complete yolk platelets suggests an all-or-none biochemical process for activating yolk consumption that is inactivated during dormancy to preserve yolk for post-dormancy development. The implications of these and additional ultrastructural features are discussed in the context of anthropogenic influence and the natural environment.

The discovery of Caligus quadratus Shiino, 1954 (Copepoda: Caligidae) in the Mediterranean Sea, with a new host record and supplementary morphological information obtained using confocal laser scanning microscope (CLSM) and 3D image processing.

In this study, supplementary information on the morphology of the siphonostomatoid copepod Caligus quadratus Shiino, 1954 (Copepoda: Caligidae) is given based on the new material collected from the gills of the Atlantic bluefin tuna, Thunnus thynnus (Linnaeus, 1758) caught in the Gulf of Antalya, Turkey. The morphology of C. quadratus is re-examined for the first time by adopting a recently developed visualisation technique by Kamanli et al. [1]. Appendages of Congo red stained specimens of C. quadratus were dissected and scanned using confocal laser scanning microscope (CLSM) and the CLSM images were processed using Dristhi software programme. 3D reconstructions of some confusing appendages were visualised using Drishti. Line drawing was used to depict the habitus of both female and male C. quadratus. Key diagnostic characters of C. quadratus are presented together with the newly observed additional taxonomic characters. In addition, previously misinterpreted and simply overlooked features in the previous descriptions of C. quadratus are also re-described. This is the first report of C. quadratus from the Mediterranean Sea and the Atlantic bluefin tuna constitutes a new host record for this caligid copepod.

Guanine crystals regulated by chitin-based honeycomb frameworks for tunable structural colors of sapphirinid copepod, Sapphirina nigromaculata.

Sapphirinid copepods, which are marine zooplankton, exhibit tunable structural colors originating from a layered structure of guanine crystal plates. In the present study, the coloring portion of adult male of a sapphirinid copepod, Sapphirina nigromaculata, under the dorsal body surface was characterized to clarify the regulation and actuation mechanism of the layered guanine crystals for spectral control. The coloring portions are separated into small domains 70-100 µm wide consisting of an ordered array of stacked hexagonal plates ~1.5 µm wide and ~80 nm thick. We found the presence of chitin-based honeycomb frameworks that are composed of flat compartments regulating the guanine crystal plates. The structural color is deduced to be tuned from blue to achromatic via yellow and purple by changing the interplate distance according to vital observation and optical simulation using a photonic array model. The framework structures are essential for the organization and actuation of the particular photonic arrays for the exhibition of the tunable structural color.

The brain and the corresponding sense organs in calanoid copepods - Evidence of vestiges of compound eyes.

Copepoda is one of the crustacean taxa with still unresolved phylogenetic relationships within Tetraconata. Recent phylogenomic studies place them close to Malacostraca and Cirripedia. Little is known about the morphological details of the copepod nervous system, and the available data are sometimes contradictory. We investigated several representatives of the subgroup Calanoida using immunohistochemical labeling against alpha-tubulin and various neuroactive substances, combining this with confocal laser scanning analysis and 3D reconstruction. Our results show that the studied copepods exhibit only a single anterior protocerebral neuropil which is connected to the nerves of two protocerebral sense organs: the frontal filament organ and a photoreceptor known as the Gicklhorn's organ. We suggest, on the basis of its position and the innervation it provides, that Gicklhorn's organ is homologous to the compound eye in arthropods. With regard to the frontal filament organ, we reveal detailed innervation to the lateral protocerebrum and the appearance of spherical bodies that stain intensely against alpha tubulin. A potential homology of these bodies to the onion bodies in malacostacan crustaceans and in Mystacocarida is suggested. The nauplius eye in all the examined calanoids shows the same basic pattern of innervation with the middle cup sending its neurites into the median nerve, while the axons of the lateral cups proceed into both the median and the lateral nerves. The early development of the axonal scaffold of the nauplius eye neuropil from the proximal parts of the nauplius eye nerves follows the same pattern as in other crustaceans. In our view, this specific innervation pattern is a further feature supporting the homology of the nauplius eye in crustaceans.

The re-discovery of Caligus lichiae Brian, 1906 (Copepoda: Caligidae) parasitic on two carangid fishes in the Mediterranean Sea, and the recognition of Caligus aesopus Wilson C. B., 1921 as a junior subjective synonym.

The caligid copepod Caligus lichiae Brian, 1906 is redescribed based on new material collected from the type-host, Lichia amia (Linnaeus), and from a second carangid, Seriola dumerili (Risso), both caught in the Gulf of Iskenderun, Turkey. Key diagnostic characters of both sexes are reported, supported by drawings and scanning electron microscopy images. Despite the commercial importance of its type-host, L. amia, C. lichiae has not been reported since its original description. After detailed comparison with recent descriptions of Caligus aesopus Wilson C. B., 1921, commonly found on S. dumerili, we recognise these two species as conspecific and propose to relegate C. aesopus Wilson C. B., 1921 to a junior subjective synonym of C. lichiae Brian, 1906. Caligus lichiae is a member of the C. confusus group of species and an identification key to species in this group is provided.

A new species of Clausidium Kossmann, 1874 (Copepoda: Cyclopoida) associated with ghost shrimps from the Persian Gulf, including female-male interlocking mechanisms and remarks on host specificity.

A new clausidiid copepod was found associated with the ghost shrimp Neocallichirus jousseaumei (Nobili) in the Persian Gulf, on the Iranian coast. The new species shares the armature formula of swimming legs 2 to 4 with C. persiaensis, but can be easily distinguished from its congeners by unique characteristics of the females: the prominent spine on endopodal segment 1 of the antenna, the armature of the maxilliped, and the elongated basis of the swimming legs. Distinguishing features observed in males include the distinct projections on the maxilliped and the armature of legs 1 and 4. In addition to traditional light microscopy-based descriptions, confocal laser scanning microscopy (CLSM) was used to obtain high resolution images and 3-D reconstructions of entire copepods. Structures of taxonomic importance that exhibit complex shapes (male maxilliped and female urosome) were scanned to generate 3-D prints that gave valuable insights about female/male interlocking mechanisms. The taxonomic status and host specificity of Clausidium spp. are discussed and a key to valid species is provided.

The discovery of Lepeophtheirus acutus Heegaard, 1943 (Copepoda: Caligidae) from two new elasmobranch hosts in the Mediterranean Sea, and a comparative redescription of Lepeophtheirus rhinobati Luque, Chaves et Cezar, 1998.

In this study, supplementary information on the morphology of the siphonostomatoid copepod Lepeophtheirus acutus Heller, 1865 is given based on new material collected from the ventral body surface and mouth cavity of common guitarfish, Rhinobatos rhinobatos (Linnaeus) and from the branchial cavity of bull ray, Aetomylaeus bovinus (Geoffroy Saint-Hilaire) caught in Iskenderun Bay, Turkey. This is the first report of L. acutus from Mediterranean waters. Key diagnostic characters of both sexes are reported, supported by light and scanning electron microscopy observations. In addition, Lepeophtheirus rhinobati Luque, Chaves et Cezar, 1998, which is closely related to L. acutus and has been reported from the same host genus, Rhinobatos, is reexamined based on paratypes stored in the collections of the United States National Museum of Natural History. Some of the key diagnostic characters which were incompletely known or lacking in the original description of both sexes of L. rhinobati are redescribed and/or presented for the first time.

Chitosan-silver nanocomposites in goldfish aquaria: A new perspective in Lernaea cyprinacea control.

Nanomedicine is a promising new research area in human and veterinary science. Metal nanoparticles have shown high biocidal activity against bacteria, fungi and viruses, few studies have focused on antiparasitic action. Therefore, this study aims to investigate the influence of chitosan-silver nanocomposites on the fish crustacean parasite Lernaea cyprinacea. The disease was detected in goldfish (Carassius auratus) aquaria during the spring. Molecular and morphometric characterizations of the parasite were performed using polymerase chain reaction for rRNA and scanning electron microscopy. Chitosan-silver nanocomposites were characterized using transmission electron microscopy and Zetasizer. Probit analysis of parasite mortality versus the logarithmic concentrations of the composites indicated that the 1h/LC50 was 5.495ppm. Parasites exposed to the chitosan-silver nanocomposites showed severe pathological alterations and adsorbed the composite particles on their cuticles. After aqueous exposure of the infected fish to the compound at its LC50 for 24h, the female lernaeids were completely dislodged. Moreover, the pathological findings indicated rapid skin wound healing and renewal at the parasitic injury site. Therefore, we concluded that chitosan-silver nanocomposites are potential parasitic control agents for ornamental glass aquaria, as they have detrimental effects on aquatic predators, such as copepods.

Scanning electron microscopy study of Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) from Tunisian waters and histopathological study of its effects on host.

Strabax monstrosus von Nordmann, 1864 (Copepoda: Chondracanthidae) is an ectoparasite and it was recently recorded from small red scorpionfish, Scorpaena notata Rafinesque, and red scorpionfish, Scorpaena scrofa L., collected from Tunisian coastal waters. Copepod females were found deeply embedded in the branchial cavity reaching the cardiac region with their mouth-parts. Observations of females and males using scanning electron microscopy showed a number of morphological features that have been previously overlooked or incompletely presented. In this study, we report for the first time the fine structures of appendages, mouthparts, external genital organs (nuptial organs), and other structures of male and female Strabax monstrosus. Histopathological study showed lesions in the cardiac region of the host fish which is the target site of the parasite. The presently reported finding is the first record of Strabax monstrosus from Scorpaena notata and Scorpaena scrofa collected from Tunisian waters.

Description of four new species and a revision of the genus Tripaphylus Richiardi in Anonymous, 1878 (Copepoda: Siphonostomatoida: Sphyriidae).

Tripaphylus Richiardi in Anonymous, 1878 is one of the genera of the Sphyriidae Wilson, 1919 and it currently accommodates ten species. Only scanty descriptions are available for the females and some males of the species. Tripaphylus specimens, described and illustrated in this paper, were collected from elasmobranch hosts off the South African coast or came from the private collection of the late Dr G. Benz. Collected specimens were fixed and preserved in 70% ethanol, examined by light - and scanning electron microscopy, and compared with the known species. Descriptions and illustrations are provided for the transformed adult females and males of T. elongatus (Wilson, 1932) and T. versicolor (Wilson, 1919) while illustrated descriptions of the transformed adult females are also provided for T. ferox (Wilson, 1919) and T. vaissierei (Delamare Deboutteville & Nuñes-Ruivo, 1954). Additionally, the material previously reported as T. ferox is considered to represent T. elongatus and that reported as T. lobatus (Kirtisinghe, 1964) is considered a junior synonym of T. vaissierei. Based on the collected material the transformed adult female and male of T. lewisi n. sp. are described as well as the adult transformed females of T. benzi n. sp., T. hoi n. sp., and T. beatricae n. sp. A summarised review of the main features is provided for each of the previously described T. musteli (van Beneden, 1851), T. hemigalei Kirtisinghe, 1964, T. australis (Kabata, 1993), T. triakis (Castro Romero, 2001) and T. asymboli (Turner, Kyne & Bennett, 2003). Furthermore, reasons are provided for the recommendation that T. hemigalei be considered a species inquirenda. An identification key to the transformed adult females of all species of Tripaphylus is provided and the host records are also updated.

Exotic "Gill Lice" Species (Copepoda: Lernaeopodidae: Salmincola SPP.) Infect Rainbow Trout (Oncorhynchus mykiss) and Brook Trout (Salvelinus fontinalis) in the Southeastern United States.

Salmincola californiensis infected 25 of 31 (prevalence 0.8; intensity 2-35 [mean 6.6 ± standard deviation 7.7; n = 25]) rainbow trout, Oncorhynchus mykiss, from a private trout farm connected to the Watauga River, North Carolina. Salmincola edwardsii infected all of 9 (1.0; 2-43 [9.3 ± 13.0; 9]) brook trout, Salvelinus fontinalis, from Big Norton Prong, a tributary of the Little Tennessee River, North Carolina. Both lernaeopodids are well-known salmonid pathogens, but neither is native to, nor has been previously taxonomically confirmed from, the southeastern United States. Herein, we (1) use light and scanning electron microscopy to identify and provide supplemental morphological observations of these lernaeopodids, (2) furnish complementary molecular sequence data from the 28S rDNA (28S), and (3) document the pathological effects of gill infections. We identified and differentiated these lernaeopodids by the second antenna (exopod tip with large [S. californiensis] vs. slender [S. edwardsii] spines; endopod terminal segment with subequal ventral processes shorter than [S. californiensis] vs. longer than or equal to [S. edwardsii] dorsal hook), maxilliped palp (length typically ≤1/3 [S. californiensis] vs. 1/3-1/2 [S. edwardsii] subchela length exclusive of claw), and bulla (sub-circular and concave on manubrium's side [S. californiensis] vs. non-stellate [S. edwardsii]). Analysis of the 28S rDNA sequences confirmed our taxonomic assignments as demonstrated by 100% sequence similarity among the sympatric, morphologically-conspecific isolates. Histopathology revealed focal gill epithelial hyperplasia, obstruction of interlamellar water channels, lamellar fusion, and crypting of gill filaments. High intensity infections by either lernaeopodid are surveillance-worthy because they are potentially pathogenic to trout in the southeastern United States.

The discovery of Caligus macrurus Heller, 1865 (Copepoda: Caligidae) in the Mediterranean Sea, and the recognition of Sciaenophilus van Beneden, 1852 as a junior synonym of Caligus Müller, 1785.

The siphonostomatoid parasitic copepod Caligus macrurus Heller, 1865 is redescribed based on new material collected from the gill filaments and pharynx of tripletail Lobotes surinamensis Bloch (Lobotidae) caught in Iskenderun Bay, Turkey. Key diagnostic characters and newly observed taxonomic features are reported, supported by light and scanning electron microscopy observations. This is the first report of C. macrurus from Mediterranean waters. Caligus macrurus is also recognised as conspecific with the better known Caligus bennetti Causey, 1953, found on the same host, which becomes a junior subjective synonym of C. macrurus. Caligus O.F. Müller, 1785 and Sciaenophilus van Beneden, 1852 have both been treated as valid genera within the family Caligidae although numerous doubts have been expressed over the validity of the latter. The morphological evidence does not support generic level distinction and we recommend the transfer of all species currently placed in Sciaenophilus into Caligus as C. tenuis (van Beneden, 1852), C. pharaonis von Nordmann, 1832, C. nibeae Shen, 1957 and C. macrurus.

Schistobrachia kabata sp. nov. (Siphonostomatoida: Lernaeopodidae) from rajiform hosts off South Africa.

The genus Schistobrachia Kabata, 1964 (Lernaeopodidae: Siphonostomatoida) currently accommodates five species of which two infect holocephalans and three utilize elasmobranchs. Kensley & Grindley (1973) reported three females from "Dipturus batis" (Linnaeus, 1758) collected in Table Bay, South Africa, which they assigned to S. ramosa (Krøyer, 1863), a species previously known only from the North Atlantic. Re-examination of these specimens (labelled Charopinus ramosus Krøyer, 1863 and deposited in the Iziko South African Museum) and additional Schistobrachia material newly collected from the gills of various Rajiformes off the South African west and south coasts, showed that Kensley & Grindley's (1973) earlier record of S. ramosa was misidentified and in reality represents a distinct species, S. kabata sp. nov. Both sexes of the new species are described using light and/or scanning electron microscopy.

Discovery of the male of the rare caligiform copepod Kabataia Kazachenko, Korotaeva & Kurochkin, 1972 (Copepoda: Siphonostomatoida), with a reconsideration of its phylogenetic affinities.

We report the discovery of the male of the rare caligiform copepod Kabataia ostorhynchi Kazachenko, Korotaeva & Kurochkin, 1972 on the gills of the type-host Oplegnathus woodwardi (Waite, 1900) captured in the Southern Ocean, off Australia. Light and scanning electron microscopy confirmed the unusual body plan of Kabataia Kazachenko, Korotaeva & Kurochkin, 1972, where only the first pedigerous somite is incorporated into the cephalothorax and the second and third pedigerous somites are fused to form a double-somite, visible both dorsally and ventrally. The adult female carries paired dorsal plates originating from the second pedigerous somite within this double-somite. In the male the second and third pedigerous somites are free and paired dorsal plates are present on the former. Kabataia exhibits sexual dimorphism in an unusually wide range of limbs. Most remarkable is the tubular extension from the exit pore of the maxillary gland at the base of the maxilla which reaches beyond the anterior margin of the mouth tube; this is present in the male only. Kabataia exhibits a functional articulation between the first and second pedigerous somites and thus lacks the diagnostic apomorphy of the family Trebiidae (incorporation of both first and second pedigerous somites into the cephalothorax). We propose to transfer Kabataia to the Pandaridae, since it shares the key synapomorphies of this family. Furthermore, we propose to transfer Innaprokofevnas Kazachenko, 2001 to the Dissonidae, which leaves Trebius Krøyer, 1838 as the only genus within the Trebiidae. The correct spelling of Philorthragoriscus Horst, 1897 is noted.

Parasitic copepods infesting the olfactory sacs of skates from the southwestern Atlantic with the description of a new species of Kroeyerina Wilson, 1932.

The olfactory sacs of 488 specimens belonging to 18 species of rajid and arhynchobatid skates from the Argentine Sea were sampled for parasites. No parasitic copepods were found in 11 host species, but siphonostomatoid specimens referable to Kroeyerina Wilson, 1932 (Kroyeriidae) and Brianella corniger Wilson, 1915 (Lernaeopodidae) were found on the spotback skate Atlantoraja castelnaui (Miranda Ribeiro, 1907), the smallnose fanskate Sympterygia bonapartii Müller & Henle, 1841, the bignose fanskate Sympterygia acuta Garman, 1877 and the zipper sand skate Psammobatis extenta (Garman, 1913) (Rajiformes: Arhynchobatidae). Additionally, specimens of B. corniger were found in the olfactory sacs of the Rio skate Rioraja agassizii (Müller & Henle, 1841) and attached to the pectoral fins of the Magellan skate Bathyraja magellanica (Philippi, 1902) and the smallthorn sand skate Psammobatis rudis Günther, 1870. A new species, Kroeyerina sudamericana sp. nov., is described and illustrated. The new species most closely resembles Kroeyerina nasuta Wilson, 1932, but can be distinguished from it by the different armature of the antennule, a proportionally shorter genital complex and the chela of the antenna which, when closed, leaves a gap between the corpus and claw, the latter having no spines. The new species represents the first record of Kroeyerina in South American marine waters. The present study also extends the distribution range of B. corniger, previously known only from the Pacific, to include Atlantic waters, and records seven new host species, all of which are members of the Arhynchobatidae.

Lernanthropid copepods parasitic on marine fishes in Turkish waters, including two new records.

A review of Lernanthropidae (Copepoda: Siphonostomatoida) recorded on marine fish species in the Mediterranean and Turkish seas is presented together with the first records of two species of the genus Lernanthropus de Blainville, 1822 that are new to the Turkish coasts. The newly recorded parasites are: Lernanthropus gisleri van Beneden, 1852 from the gill filaments of Umbrina cirrosa (Linnaeus, 1758) and Lernanthropus callionymicola El-Rashidy & Boxshall, 2012 from the gill filaments of the Red Sea immigrant dragonet Callionymus filamentosus Valenciennes, 1837. General morphology, measurements and key diagnostic characters of both species are presented, based on light and scanning electron microscopy. In addition, some contradictions are noted in previous descriptions of L. gisleri and some newly observed structural details of L. callionymicola are also presented.

Colobomatus kimi sp. nov. (Copepoda: Philichthyidae) parasitic in the dwarf goatfish Upeneus parvus Poey, 1852 (Perciformes: Mullidae) in the South Atlantic Ocean.

A new species of copepod, Colobomatus kimi sp. nov., belonging to the cyclopoid family Philichthyidae Vogt, 1877, is proposed based on female specimens collected from the pores of the cephalic sensory system of the dwarf goatfish, Upeneus parvus Poey from the southeastern Brazilian coastal zone. The new species can be distinguished from its closest congeners by the unique combination of characters displayed by the female, including the forked caudal rami, the position of the midventral cephalic process shorter in relation to the lateral cephalic processes, and the presence of paired genital processes. The new species is the first member of Colobomatus Hesse, 1873 found to parasitize mullids of the genus Upeneus.

A review of the Taeniacanthus balistae species group (Crustacea: Copepoda: Taeniacanthidae), with descriptions of two new species.

The Taeniacanthus balistae species group is characterized by two displaced elements on an outwardly curved and elongated terminal exopodal segment of leg 4. Members of this group parasitize tetraodontiform fishes. The group is reviewed herein based on both new material collected from tetraodontiform fishes and re-examination of voucher specimens housed at the Smithsonian Institution, U.S.A. Five species are considered valid in this group, including two new species described here, Taeniacanthus dojirii sp. nov. from diodontid hosts collected from the Indo-West Pacific and Taeniacanthus ryukyuensis sp. nov. from balistid hosts collected from the Ryukyu Islands, Japan. Taeniacanthus dojirii sp. nov. differs from other members of the group by having in the female stout spines on the terminal endopodal segment of legs 2 to 4 and on the exopod of leg 5, as well as highly reduced setae on the last two exopodal segments of leg 4. Taeniacanthus ryukyuensis sp. nov. differs from other members of the group by having in the female 16-18 incomplete rows of spinules on the anal somite, minute teeth on the straight terminal claw of the maxilliped and well-developed spinulated flanges on the rami of legs 2 to 4. Supplemental morphological observations, as well as new host and locality records for Taenicanthus balistae (Claus, 1864) and Taeniacanthus similis Dojiri & Cressey, 1987, are also provided.

A new species of Monstrilla Dana, 1849 (Copepoda: Monstrilloida: Monstrillidae) from Korea, including a key to species from the north-west Pacific.

A new species of monstrilloid copepod belonging to the genus Monstrilla Dana, 1849 is recorded from South Korea. Specimens were obtained between May of 2012 and January of 2014 from inshore waters along the coasts of the East Sea, South Sea, and Jeju Island, using a light trap installed at quays and wharves overnight. Monstrilla ilhoii sp. nov. is characterized by a remarkable combination of a large body size (females about 3.8 mm long, males about 2.8 mm long), a polygonal ridge pattern (cuticular reticulation) over the entire body surface, and an antennule armature featuring a supernumerary spiniform seta (4d3) in females and a dagger-shaped distal spine (62) in both sexes. In other respects M. ilhoii sp. nov. most closely resembles M. lata Desai & Bal, 1963; both species have one and three setae on the endopodal and exopodal lobes, respectively, of female leg 5, a horseshoe-shaped male genital apparatus with marked undulations along the whole distal margin, and six setae on each caudal ramus in both sexes. This paper provides a description of the new species, taxonomic remarks on its morphological features, and differential diagnoses with respect to its allies. Scanning electron microscopy was used to document significant morphological microcharacters. The species of Monstrilla known from five sub-regions of the north-west Pacific are enumerated with the source references, and keys to the females and males of these species are provided.

Two new species of the genus Monstrillopsis Sars, 1921 (Copepoda: Monstrilloida: Monstrillidae) from South Korea.

Monstrilloid copepods of the genus Monstrillopsis Sars, 1921 are recorded from Korea, as well as from the northwestern Pacific, for the first time. Specimens were obtained using a light trap set overnight at piers or seawalls in small harbors. Males of two new species were found and are described herein with remarks on their affinities and detailed drawings and SEM photographs of their morphological features. Monstrillopsis longilobata sp. nov. is allied to M. chathamensis Suárez-Morales & Morales-Ramírez, 2009 and M. sarsi Isaac, 1974 in having the character combination of a long, claw-like apical spinous process on the male antennule and elongate genital lappets. It differs from them in having conspicuous transverse striations on the dorsal surface of the cephalothorax and extremely long male genital lappets, which extend far beyond the anterior margins of the caudal rami. Monstrillopsis coreensis sp. nov. also has a claw-like apical spinous process of the male antennule and conspicuous transverse striations on the dorsal surface of the cephalothorax, but it differs from M. longilobata in having a much longer and stronger apical spine of the antennule and a relatively shorter and undulating genital apparatus.