Description of Discocotyle ciray n. sp. (Monogenea: Discocotylidae) from Parahucho perryi (Brevoort) from Hokkaido, Japan, with a redescription of D. sagittata (Leuckart, 1842).

Discocotyle sagittata (Leuckart, 1842) (Monogenea: Discocotylidae) is redescribed, based on specimens collected from the type host, Salmo trutta Linnaeus, from the type locality, Freiburg, Germany, supplemented with specimens from S. trutta and rainbow trout, Oncorhynchus mykiss (Walbaum) reared in an Austrian aquarium. The diagnosis of the genus Discocotyle Diesing, 1850 is emended. Discocotyle ciray n. sp. is described, based on immature, preadult and adult specimens from the salmonid, Parahucho perryi (Brevoort) at Eniwa, Hokkaido, Japan. Adult specimens of the new species were about twice as large as those of D. sagittata from S. trutta. When the type specimens of D. ciray n. sp. were examined together with museum specimens from P. perryi at Tsurui, Hokkaido, the body and clamp sizes were positively correlated to the host size. Their measurements from a smaller P. perryi at Tsurui overlapped with those of D. sagittata, showing that these size differences were not suitable differentiating keys. Discocotyle ciray n. sp. can be separated from D. sagittata by the morphologies of the female genital system (relatively anteriorly positioned ovary, short joint vaginal duct and much more strongly winding uterus). The genetic distances of COI mtDNA sequence between D. ciray n. sp. and D. sagittata were 18.0-18.6%. These remarkable genetic divergences also supported the distinct taxonomic status of D. ciray n. sp.

Prediction of early falls using adherence and balance assessments in a convalescent rehabilitation ward.

Objectives: To predict falls by adding an adherence assessment to a static balance ability assessment, and to evaluate fall prediction accuracy. Methods: This study included 416 patients who were admitted to a 45-bed convalescent rehabilitation ward over a 2-year period. The patients were assessed at the time of admission using the Standing Test for Imbalance and Disequilibrium (SIDE) and three additional, newly developed adherence items. Patients were divided into two groups: a group that experienced falls (fall group) and a group that did not experience falls (non-fall group) within 14 days of admission. The sensitivity and specificity of the assessment items for predicting falls were calculated. Results: Sensitivity was 0.86 and specificity was 0.42 when the cutoff was between SIDE levels 0-2a and 2b-4. Combining balance assessment using the SIDE with the memory and instruction adherence items improved fall prediction accuracy such that the sensitivity was 0.75 and the specificity was 0.64. Conclusions: Our analysis suggested that adherence assessment can improve fall risk prediction accuracy.

Effect of light exposure on circadian rhythm in theront excystment in Cryptocaryon irritans.

We examined the effects of light exposure on the theront excystment circadian rhythm in Cryptocaryon irritans using a newly invented apparatus, which enabled us to examine the excystment rhythms of theronts from tomonts with low labor. Using the apparatus, we examined the timings of theront excystment from tomonts exposed directly to light and from tomonts exposed to light-exposed seawater by counting the number of excysted theronts. We found that the theront excystment time changed only when tomonts were directly exposed to light, indicating that light reception is essential for circadian rhythm entrainment. When tomonts were exposed to light only once for 12 h, either on Day 1, Day 2, or Day 3 after leaving host and being encysted, the circadian rhythm was entrained according to the photoperiod given on tomonts. Tomonts exposed to a low light (1 lx) with 12L:12D photoperiod daily showed a circadian rhythm similar to that in tomonts exposed to an intense light (500 lx) under the same photoperiod. When tomonts were incubated at 22 °C, 25 °C, or 28 °C under the same photoperiod, almost the same circadian rhythm was developed, suggesting temperature has little effect on the circadian rhythm entrainment between the range, even though the date of excystment was delayed in lower temperatures. These results suggest the circadian rhythm of theront excystment can be entrained in tomonts on the seabed of inner bays where net-cage aquaculture is conducted, and be involved in the outbreaks of cryptocaryoniasis there.

Genomic diversity of wild and cultured Yesso scallop Mizuhopecten yessoensis from Japan and Canada.

The Yesso scallop Mizuhopecten yessoensis is an important aquaculture species that was introduced to Western Canada from Japan to establish an economically viable scallop farming industry. This highly fecund species has been propagated in Canadian aquaculture hatcheries for the past 40 years, raising questions about genetic diversity and genetic differences among hatchery stocks. In this study, we compare cultured Canadian and wild Japanese populations of Yesso scallop using double-digest restriction site-associated DNA (ddRAD) sequencing to genotype 21,048 variants in 71 wild-caught scallops from Japan, 65 scallops from the Vancouver Island University breeding population, and 37 scallops obtained from a commercial farm off Vancouver Island, British Columbia. The wild scallops are largely comprised of equally unrelated individuals, whereas cultured scallops are comprised of multiple families of related individuals. The polymorphism rate estimated in wild scallops was 1.7%, whereas in the cultured strains, it ranged between 1.35 and 1.07%. Interestingly, heterozygosity rates were highest in the cultured populations, which is likely due to shellfish hatchery practices of crossing divergent strains to gain benefits of heterosis and to avoid inbreeding. Evidence of founder effects and drift was observed in the cultured strains, including high genetic differentiation between cultured populations and between cultured populations and the wild population. Cultured populations had effective population sizes ranging from 9 to 26 individuals whereas the wild population was estimated at 25,048-56,291 individuals. Further, a depletion of low-frequency variants was observed in the cultured populations. These results indicate significant genetic diversity losses in cultured scallops in Canadian breeding programs.

Neuropsychological tests used for dementia assessment in Japan: Current status.

AIM: This study aimed to investigate the assessment tools dementia specialists use in clinical practice, reasons for their use and assessment-related factors. METHODS: A questionnaire survey was carried out from 15 September 2021 to 20 October 2021 among 1858 dementia specialists in Japan, with responses obtained via mail or using a Web form accessed via a Web address. RESULTS: Of the 1858 specialists who were sent the questionnaire, 574 responded, yielding a response rate of 32.2%. Almost all respondents stated that the main purposes of neuropsychological testing were to identify the pathophysiology and aid diagnosis. Most respondents identified behavioral and psychological symptoms of dementia as important factors for assessment. The most commonly used tests were the Hasegawa Dementia Scale-Revised and Mini-Mental State Examination, often used as screening tools. The Mini-Mental State Examination, Clock Drawing Test and Cube Copying Test were common assessments carried out directly by specialists. Quality of life and burden of care were less commonly assessed. CONCLUSIONS: Despite the main purpose of carrying out neuropsychological tests on dementia patients is to "understand the pathophysiology" and "aid in diagnosis," many assessment methods were chosen as screening methods carried out in a short time during clinic hours. The lack of evaluation of care burden and QOL, considered important by specialists, is an issue for the future in treating people with dementia, a life disability. Geriatr Gerontol Int 2023; ••: ••-••.

Identification of glycine betaine as a host-derived molecule required for the vegetative proliferation of the protozoan parasite Perkinsus olseni.

Perkinsus olseni is an industrially significant protozoan parasite of Manila clam, Ruditapes philippinarum. So far, various media, based on Dulbecco's Modified Eagle Medium and Ham's F-12 nutrient mixture with supplementation of fetal bovine serum (FBS), have been developed to proliferate the parasitizing trophozoite stage of P. olseni. The present study showed that P. olseni did not proliferate in FBS-deficient Perkinsus broth medium (PBMΔF), but proliferated well in PBMΔF supplemented with tissue extract of host Manila clams, indicating that FBS and Manila clam tissue contained molecule(s) required for P. olseni proliferation. Preliminary characterization suggested that the host-derived molecule(s) was a heat-stable molecule(s) with a molecular weight of less than 3 kDa, and finally a single molecule required for the proliferation was purified by high-performance liquid chromatography processes. High-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses identified this molecule as glycine betaine (=trimethylglycine), and the requirement of this molecule for P. olsseni proliferation was confirmed by an assay using chemically synthesized, standard glycine betaine. Although glycine betaine was required for the proliferation of all examined Perkinsus species, supplementation of glycine betaine precursors, such as choline and betaine aldehyde, enhanced the proliferation of 4 Perkinsus species (P. marinus, P. chesapeaki, P. mediterraneus and P. honshuensis), but not of 2 others (P. olseni and P. beihaiensis). Thus, it was concluded that the ability to biosynthesise glycine betaine from its precursors varied among Perkinsus species, and that P. olseni and P. beihaiensis lack the ability required to biosynthesize glycine betaine for proliferation.

Effects of temperature on Anisakis simplex sensu stricto L3 larvae experimentally challenged in rainbow trout (Oncorhynchus mykiss) and Mozambique tilapia (Oreochromis mossambicus).

Human anisakiasis is a foodborne disease that has been increasingly reported worldwide and is caused by the consumption of raw or undercooked seafood infected with zoonotic nematodes of the genus Anisakis Dujardin, 1845. One of the most frequently reported species, both in fish paratenic hosts as well as in human patients, is Anisakis simplex sensu stricto (s.s.), which is distributed within some of the globe's main fishing grounds in the North Pacific and Atlantic oceans. In order to clarify the influence of temperature on this parasite in vivo, third-stage larvae of A. simplex s.s. were surgically challenged in the body cavities of rainbow trouts (Oncorhynchus mykiss) and Mozambique tilapias (Oreochromis mossambicus). Larval survival and tissue migration were then analyzed after 6 and 12 weeks. The results showed that survival rates of larvae were lower at 27 and 33 °C than at 3, 9, 15 and 21 °C. Also, migration to the body muscle was observed to be highest at 9 °C. These results suggest that third-stage larvae of A. simplex s.s. are more adapted to lower temperatures in experimentally challenged fish, which may justify its distribution in cold northern waters.

Expression and functional analyses for estrogen receptor and estrogen related receptor of Yesso scallop, Patinopecten yessoensis.

Estrogen receptors (ERs) were known as estrogen-activated transcription factors and function as major reproduction regulators in vertebrates. The presence of er genes had been reported in Molluscan cephalopods and gastropods. However, they were considered as constitutive activators with unknown biological functions since reporter assays for these ERs did not show a specific response to estrogens. In this study, we tried characterization of ER orthologues from the Yesso scallop, Patinopecten yessoensis, in which estrogens had been proven to be produced in the gonads and involved in the spermatogenesis and vitellogenesis. Identified ER and estrogen related receptor (ERR) of Yesso scallops, designated as py-ER and py-ERR, conserved specific domain structures for a nuclear receptor. Their DNA binding domains showed high similarities to those of vertebrate ER orthologues, while ligand binding domains had low similarities with them. Both the py-er and py-err expression levels decreased in the ovary at the mature stage while py-vitellogenin expression increased in the ovary by quantitative real-time RT-PCR. Also, the py-er and py-err showed higher expressions in the testis than ovary during the developing and mature period, suggesting both genes might function in the spermatogenesis and testis development. The py-ER showed binding affinities to vertebrate estradiol-17ß (E2). However, the intensity was weaker than the vertebrate ER, indicating scallops might exist endogenous estrogens with a different structure. On the other hand, the binding property of py-ERR to E2 was not confirmed in this assay, speculating that py-ERR was a constitutive activator as other vertebrate ERRs. Further, the py-er was localized in the spermatogonia in the testis and in the auxiliary cells in the ovary by in situ hybridization, indicating its potential roles in promoting spermatogenesis and vitellogenesis. Taken together, the present study demonstrated that py-ER was an authentic E2 receptor in the Yesso scallop and might have functions for the spermatogonia proliferation and vitellogenesis, while py-ERR was involved in the reproduction by undiscovered manners.

Reduction of multiple-caregiver assistance through the long-term use of a transfer support robot in a nursing facility.

The long-term use of transfer support robots in nursing facilities is an important option for improving the efficiency of care work. The "Resyone" transfer support robot is a combination of an electric care bed and a wheelchair, and the wheelchair half of the bed can be detached at the touch of a button. The purpose of this study was to investigate how the long-term use of Resyone would improve the performance of transfer assists, such as reducing the need for multiple caregivers. One Resyone was installed in a nursing facility in Japan and 17 caregivers used it for more than 11 months. The time and number of caregivers required for each transfer assist were surveyed for three 1-week periods: 1 week before (Phase 1) and at 3 weeks (Phase 2) and 11 months (Phase 3) after the introduction of Resyone. In Phase 1, approximately 60% of all transfer assists were performed by two caregivers, but in Phase 2, this was reduced to approximately 20%, and finally, in Phase 3, all transfer assists were performed by a single caregiver. These results suggested that the long-term use of Resyone was associated with improved work efficiency in transfer assistance in a nursing facility.

Effects of temperature on eggs and larvae of Anisakis simplex sensu stricto and Anisakis pegreffii (Nematoda: Anisakidae) and its possible role on their geographic distributions.

Effects of temperature on development of eggs, recently hatched larvae and L3 larvae of the marine parasitic nematodes Anisakis simplex sensu stricto (s.s.) and A. pegreffii were examined in vitro. The eggs of A. simplex s.s. hatched at 3-25 °C and those of A. pegreffii hatched at 3-27 °C. Days before hatching varied between 2 days at 25 °C and 35-36 days at 3 °C in A. simplex s.s. and between 2 and 3 days at 27 °C and 65 days at 3 °C in A. pegreffii. Hatching rates of A. simplex s.s. were maintained high at temperatures between 3 and 25 °C but decreased to 0% at 27 °C. In contrast, those of A. pegreffii were lowest particularly at 3 °C, but also at 27 °C. The mean 50% survivals of hatched larvae ranged from 5.3 days at 25 °C to 82.3 days at 9 °C in A. simplex s.s., while in A. pegreffii it ranged from 1.2 days at 27 °C to 77.2 days at 9 °C. L3 larvae of A. pegreffii exhibited higher survival rates and activity than those of A. simplex s.s., particularly at 20 and 25 °C. These results suggest that the early stages of A. simplex s.s. are more adapted to lower temperatures whereas those of A. pegreffii are more tolerant to warm environments, which may correspond to their distribution patterns in Japan and Europe.

Molecular and microscopic identification of Eomarteilia granula infection in Manila clam Ruditapes philippinarum off the south coast of Korea.

A report on the new species Eomarteilia (=Marteilia) granula infecting Manila clam Ruditapes philippinarum from Japan in 2014 suggests the possibility of E. granula infecting other Manila clam populations in the Northwest Pacific region, including Korea. In this study, we report the first infections by E. granula in Manila clams off the south coast of Korea. Histology revealed Marteilia-like plasmodia in the digestive tubule epithelia. Tissue imprints demonstrated that each parasite sporangium enclosed 4 spores and transmission electron microscopy (TEM) revealed ultrastructure of primary cells enclosing secondary cells, which contained spores. Mature spores consisted of 3 sporoplasms: outermost, intermediate, and innermost. The outermost sporoplasm showed a peripheral electron-dense monolayer characteristic of E. granula. The 18S rDNA amplified from the Marteilia-like parasite yielded 1784-bp PCR amplicon sequences which were 99.8% similar to that of E. granula previously reported (as M. granula) from Japan. In the molecular phylogenetic analysis, the novel Marteilia-like organism formed a well-supported clade with E. granula. Accordingly, we concluded that the novel Marteilia-like parasite that we found infecting some Korean Manila clams is Eomarteilia granula. Field surveys revealed that the infection was limited to clams of the south coast of Korea, with the prevalence ranging from 3.3 to 5.0%.

A rise-assisting robot extends life space and improves facial expressions of nursing home residents.

BACKGROUND: The introduction of nursing care-support devices using robotic technology is expected to reduce the task burden in long-term care facilities. OBJECTIVE: To investigate the use of the rise-assisting robot, Resyone, in extending and improving the life space of nursing home residents with severe care needs. METHODS: We performed a feasibility study in which Resyone was used to facilitate visits to additional sites in and around the nursing home as part of the care package of three residents. Two weeks before and four weeks after implementation of the new arrangements, the 30 caregivers involved were asked to record transfer times and destinations, while also checking the residents' facial expressions. RESULTS: Before implementation, participants had limited life spaces, but afterwards they regularly visited additional destinations including the garden, home entrance and corridors, which previously they had not visited frequently. The residents' facial expressions became more positive and less negative. This study demonstrates that Resyone can enrich care activities in severely disabled individuals. CONCLUSION: These findings suggest that the sustainable use of Resyone would improve the quality of care at care facilities. Moreover, the extension of otherwise limited life space has the potential to improve care receivers' quality of life. TRIAL REGISTRATION: UMIN Clinical Trials Registry No. UMIN000039204 (20/01/2020); retrospectively registered; interventional study; parallel, non-randomized, single blinded. URL of trial registry records: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000044709 .

Life-Space Activities Are Associated with the Prognosis of Older Adults with Cardiovascular Disease.

Life-space activities are a measure of daily activity level. Here, we examined the association between life-space activities and prognosis in 129 cardiovascular diseases (CVD) patients 65 years of age or older (average age, 79.2 ± 7.6 years; mean left ventricular ejection fraction, 56.7 ± 13.2%) who had been admitted to our hospital for worsening CVD. Subjects were followed, and the primary endpoints were cardiovascular hospitalization and cardiovascular death. Receiver operating characteristic analysis produced a cutoff value for life-space assessment (LSA) score for increased risk of cardiovascular hospitalization for two years of 53.0 points (sensitivity, 55.9%; specificity, 82.1%). Kaplan−Meier analysis using this cutoff value revealed that the rates of cardiovascular hospitalization and cardiovascular death were significantly higher in subjects with an LSA score below the cutoff than in those with a score above the cutoff (both p < 0.001). Cox proportional analysis revealed that low LSA score was independently associated with cardiovascular hospitalization (HR, 2.540; 95% CI, 1.135−5.680; p = 0.023) and cardiovascular death (HR, 15.223; 95% CI, 1.689−137.180; p = 0.015), even after adjusting for age, sex, left ventricular ejection fraction, and log-transformed brain natriuretic peptide level. Thus, life-space activities are associated with prognosis in older adults with CVD.

Investigating proficiency using a lift-type transfer support device for effective care: comparison of skilled and unskilled nursing homes.

PURPOSE: The purpose of the study was to investigate whether the sustained use of the "Hug," a "hugging" type robotic transfer support device, could increase the level of quality of care. METHODS: The effect of proficiency on using the device was examined in terms of time spent for transfer, ratio of transfers using the device, and range of targets. The results were compared between skilled care facilities that had used the device for >24 months and unskilled facilities. RESULTS: The time spent for transfer at the unskilled facility was 4.6 min (2nd week after introduction), was reduced to 3.0 min (5th week), and 1.5 min at the skilled facility. The usage ratio at the unskilled facility was 13% and 30% (2nd and 5th week, respectively), while it was 97% in the skilled facility. Further, we identified wider in the range of target care recipients in the skilled facility. CONCLUSION: It takes time to master the use of Hug; however, its use was associated with many positive aspects, especially from the perspective of care recipients, e.g., better care, use of their own legs, and reduced time for transfers. These findings suggest that the widespread use of Hug would improve the quality of care.IMPLICATIONS FOR REHABILITATIONLess physically burdened on the caregivers using Hug, they can afford to talk to the care recipients.Using recipient's own legs during transfers, it prevents leg muscle disuse.As reduced time for transfers, recipients will have more opportunities to get out of bed.

Establishment and characteristics of Perkinsus beihaiensis in vitro isolates from Mediterranean mussels Mytilus galloprovincialis.

Two monoclonal in vitro isolates of Perkinsus beihaiensis were established from tissues of infected Mediterranean mussels Mytilus galloprovincialis, using a lipid concentrate and yeast extract medium (LpcYM) to induce enlarged prezoospoangia from histozoic trophozoites, and Perkinsus broth medium (PBM) to support subsequent zoosporulation and schizogonic proliferation from those cells. Zoospores of the isolates developed into uninucleate signet-ring trophozoites followed by schizonts typical of Perkinsus spp., but an additional type of unknown botryoidal cell clusters appeared and increased in density. These botryoidal cell clusters had second-generation daughter schizonts within which further internal cells were produced. Although botryoidal cell clusters in primary cultures rarely proliferated in PBM, cells contained by botryoidal clusters enlarged as prezoosporangia in LpcYM, and a large number of proliferative stages (i.e. trophozoites and schizonts typical for Perkinsus spp.) were obtained from these prezoosporangia in PBM. At lower cell density, trophozoites transformed into the botryoidal cell clusters in PBM, and the number of cells increased little, while trophozoites rapidly increased by typical schizogony at higher density in PBM. Based on these observations, we determined an optimal cell density for continuous culture of P. beihaiensis isolates, confirmed their ability to proliferate and survive after cryopreservation, and describe an experimental protocol to culture this most recently described species in the genus Perkinsus.

Benefits of a Balance Exercise Assist Robot in the Cardiac Rehabilitation of Older Adults with Cardiovascular Disease: A Preliminary Study.

We examined whether adding robot-supported balance exercises to cardiac rehabilitation improves the ability to balance in older adults with cardiovascular disease (CVD). We conducted a prospective study in 52 older adults who had been hospitalized for worsening CVD. Once weekly for four months, for a total of sixteen sessions as outpatients, the subjects used a Balance Exercise Assist Robot (BEAR) to perform balance exercises and an ergometer for aerobic exercises. Participants' mean age was 76.9 ± 6.8 years (range, 65−95 years), and their mean brain natriuretic protein level was 164.0 ± 190.0 pg/mL. After the intervention, participants showed significant improvements in gait speed (before, 1.06 ± 0.33 m/s; after, 1.23 ± 0.30 m/s; p < 0.001), Short Physical Performance Battery score (before, 10.02 ± 2.25; after, 10.88 ± 1.79; p ˂ 0.001), timed up-and-go (before, 11.11 ± 5.07 s; after, 9.45 ± 3.45 s; p ˂ 0.001), and knee extension (before, 26.97 ± 11.78 kgf; after, 30.13 ± 13.04 kgf; p = 0.001). Cardiac rehabilitation including exercises using BEAR improved physical functioning and the ability to balance in older adults with CVD. Frail and prefrail patients improved, whereas robust ones did not change.

Five new and two known species of Heterobothrium (Monogenea: Diclidophoridae) infecting puffers of the genus Takifugu from Japanese waters.

Seven species of puffers of the genus Takifugu caught in Japanese waters were examined for monogeneans on the gills. Five new species of Heterobothrium (H. gotoi n. sp. from T. porphyreus, H. tabetai n. sp. from T. vermicularis, H. aljufailiae n. sp. and H. iwatai n. sp. from T. snyderi, H. matsubarai n. sp. from T. stictonotus) and two known species (H. praeorchis Bychowsky, Mamaev & Nagibina, 1976 from T. pardalis, T. chrysops and T. flavipterus and H. bychowskyi Ogawa, 1991 from T. flavipterus) were found and described. Heterobothrium tetrodonis of Iwata (1991) was synonymized with H. bychowskyi. Currently, a total of 11 species of Heterobothrium, including the seven species in this study, were recorded from nine species of Japanese Takifugu spp. Ten species excluding H. praeorchis were found from a single host species, suggesting that they are highly host-specific and have co-evolved with the host Takifugu spp. Tagia Sproston, 1946 is synonymized with Heterobothrium. Earlier divergence of Heterobothrium of tetraodontid puffers in Diclidophoridae was suggested by the large subunit ribosomal DNA (rDNA) analyses, and interspecific relationships in this genus inferred from the internal transcribed spacer region of rDNA well corresponded to those inferred from their morphology and adhesive mode to the gills. Including the five new species and synonymization of Tagia with Heterobothrium, the genus Heterobothrium now comprises 19 species.

Supplementation with lipids enhances zoosporulation of Perkinsus species.

The protozoan parasite Perkinsus olseni is a major pathogen of marine mollusks. A large number of zoospores (the most infective stage) is required to experimentally examine the transmission and invasion processes of this parasite, but the conventional zoosporulation method in seawater is inefficient. A recent study found that P. olseni zoosporulation was highly enhanced in a nutrient-rich medium which was developed for trophozoite proliferation in Perkinsus. Here, we examined the effect of each medium component on P. olseni zoosporulation and found that lipids enhanced zoosporulation. Moreover, zoospores failed to develop into trophozoites in seawater supplemented with lipids, indicating that this zoosporulation method using seawater supplemented with lipids is ideal for preparing a large number of P. olseni zoospores for various biological assays. Lipid supplementation also significantly enhanced zoosporulation in P. honshuensis, P. chesapeaki, and P. marinus, although the enhancing effect of the lipid supplementation varied by species. Considering the limited availability of lipids in the sea water column, our findings suggest that Perkinsus zoosporulation likely occurs mainly in the vicinity of hosts (not in the sea water column), such as in the mantle cavity or on the body surface of mollusk hosts.

Emendation of the genus Neoheterobothrium and a proposal of a new genus Paraheterobothrium (Monogenea: Diclidophoridae) for five species of diclidophorids from Pleuronectiform fishes.

Neoheterobothrium chilense González, Oliva & Acuña, 2002 is redescribed based on newly collected specimens from the type host, Hippoglossina macrops and type locality (Coquimbo, Northern Chile). Type specimens of Neoheterobothrium hippoglossini Piasecki, Wierzbicka & Kempter, 2000 and Choricotyle exilis Crane, 1972 are also redescribed. These three diclidophorid monogeneans infecting pleuronectiform flatfishes have pre-ovarian seminal receptacle, ootype inside the semicircle of ovary and elongated pharynx, differentiated from the most similar Orbocotyle Euzet & Suriano, 1975 in that members of the latter genus possess post-ovarian seminal receptacle, post-ovarian ootype and cylindrical or pyriform pharynx. Paraheterobothrium n. g. is proposed for P. chilense n. comb. (type), P. hippoglossini n. comb., P. exilis n. comb., P. papillosum n. comb. and P. syacii n. comb. A redescription of Neoheterobothrium affine (Linton, 1898), the type species of the genus, based on voucher specimens confirmed differences from the new genus in the presence of lamellate plate in the anterior jaw of clamps, absence of seminal receptacle and ovoid pharynx. The genus Neoheterobothrium was emended and N. cynoscioni (MacCallum, 1917) and N. mcdonaldi Payne, 1987 were removed from the genus. Neoheterobothrium now comprises N. affine (type), N. insulare Oliva & Luque, 1995, N. hirame Ogawa, 1999, and N. paralichthyi Suriano & Labriola, 1999, all of them parasites of flatfishes of the genus Paralichthys. Molecular analyses with the internal transcribed spacer 1 distinguished the clade for Paraheterobothrium spp. (P. chilense n. comb. and P. papillosum n. comb.) and Neoheterobothrium spp. (N. hirame, N. affine and N. paralichthyi), supporting this taxonomic emendation.