Species Of Endoparasites Research Articles

Seasonal variation of gastro-intestinal helminths of three bat species in the dry forest of western Mexico

Studies on helminths of chiropterans are relatively uncommon compared to those of other animals, and seasonal changes in helminth load have been rarely examined. We characterized the gastro-intestinal helminth load of 3 bats species to test for the existence of seasonal changes in response to known seasonal environmental and bat prey fluctuations. We did not find seasonal variation in most of the cases. However, the prevalence of 4 endoparasite species was significantly higher during one of the seasons. The highest richness was registered in Pteronotus parnellii during the wet season. The effective number of species was higher during the dry season in the 3 species of Pteronotus. Diet seems to be an important driver of helminth infracommunity structure, but we found heterogeneous patterns in the relationship between diversity and load of helminths and seasonal patterns of bat's diets and abundance of potential intermediate hosts.

Fish parasites as indicators of organic pollution in southern Brazil.

Increasing urbanization along riverbanks is a constant source of stressors to the aquatic community, and the use of bioindicators is suitable to detect and monitor the effect of each stressor. We investigated the parasites of the 'cará' fish (Geophagus brasiliensis) as potential bioindicators in a river whose banks are subject to increasing anthropogenic pressure. Samples were taken at four points of the Sangradouro River, in Florianópolis, southern Brazil, bimonthly for 12 months. Water temperature, pH, dissolved oxygen, conductivity and salinity were measured at each point and water samples were taken for nutrient analysis (total nitrogen, nitrite, total ammonia nitrogen, total phosphorus, phosphate), and total and faecal coliforms. A generalized linear model (GLM) was constructed using the abundance of each parasite species as the response variable and biometric characteristic of the fish and water variables as possible predictors. Among the 137 fish examined, 114 (83.2%) were parasitized by at least one parasite species. Two species of ectoparasites (Sciadicleithrum guanduensis and Neascus-type metacercariae) and two species of endoparasites (Pandosentis aff. iracundus and Homalometron pseudopallidum) were observed. This is the first record of the genus Pandosentis in Brazilian waters and the first record of the species G. brasiliensis as a host for this parasite. Among the analysed groups of parasites, monogeneans and acanthocephalans proved to be the most sensitive to the concentrations of dissolved oxygen, faecal coliforms and total ammonia nitrogen in the water. Our study suggests that the abundance of both monoxenic and heteroxenous parasites can be negatively affected by organic pollution in the aquatic environment, reinforcing the potential of fish parasites as indicators of water quality.

Parasitic diversity of a wild Satanoperca jurupari population, an ornamental cichlid in the Brazilian Amazon

ABSTRACT Assessment of biodiversity is fundamental for the understanding of ecological interactions, but fish parasites were neglected in biodiversity estimates for a long time. The aim of this paper was to investigate the diversity of parasites in Satanoperca jurupari in the Amazon River system in Brazil. Of the fish examined, 90.0% were parasitized by one or more species of protozoans and metazoans, and a total of 3,110,094 parasites were collected. Ichthyophthirius multifiliis, Piscinoodinium pillulare, Sciadicleithum juruparii, Clinostomum marginatum, Posthodiplostomum sp., Genarchella genarchella, Argulus multicolor and Ergasilus coatiarus were found. However, I. multifiliis and P. pillulare were the most prevalent, abundant and dominant parasites, while A. multicolor and G. genarchella were the least prevalent and abundant parasites. The parasites had an aggregate dispersion, but E. coatiarus and the endoparasite species had a higher aggregation pattern. The species richness of parasites varied from 1 to 8 species per host, the Brillouin index varied from 0.32 to 1.09 and evenness varied from 0.01 to 0.47. The host size did not influence the diversity indices and the abundance of parasites, which did not affect the body condition of the hosts. Satanoperca jurupari is a new host for G. genarchella.

Comparing and contrasting life history variation in four aphid hyperparasitoids

1. In primary parasitoids, significant differences in life history and reproductive traits are observed among parasitoids attacking different stages of the same host species. Much less is known about hyperparasitoids, which attack different stages of primary parasitoids. 2. Parasitoids exploit hosts in two different ways. Koinobionts attack hosts that continue feeding and growing during parasitism, whereas idiobionts paralyse hosts before oviposition or attack non-growing host stages, e.g. eggs or pupae. 3. Koino-/idiobiosis in primary parasitoids are often associated with different expression of life history trade-offs, e.g. endo- versus ectoparasitism, high versus low fecundity and short versus long life span. 4. In the present study, life history parameters of two koinobiont endoparasitic species (Alloxysta victrix; Syrphophagus aphidivorus), and two idiobiont ectoparasitic species (Asaphes suspensus; Dendrocerus carpenteri) of aphid hyperparasitoids were compared. These hyperparasitoids attack either the parasitoid larva in the aphid before it is killed and mummified by the primary parasitoid or the parasitoid prepupa or pupa in the dead aphid mummy. 5. There was considerable variation in reproductive success and longevity in the four species. The idiobiont A. suspensus produced the most progeny by far and had the longest lifespan. In contrast, the koinobiont A. victrix had the lowest fecundity. Other developments and life history parameters in the different species were variable. 6. The present results reveal that there was significant overlap in life history and reproductive traits among hyperparasitoid koinobionts and idiobionts, even when attacking the same host species, suggesting that selection for expression of these traits is largely association specific.

Population expansion and individual age affect endoparasite richness and diversity in a recolonising large carnivore population

The recent recolonisation of the Central European lowland (CEL) by the grey wolf (Canis lupus) provides an excellent opportunity to study the effect of founder events on endoparasite diversity. Which role do prey and predator populations play in the re-establishment of endoparasite life cycles? Which intrinsic and extrinsic factors control individual endoparasite diversity in an expanding host population? In 53 individually known CEL wolves sampled in Germany, we revealed a community of four cestode, eight nematode, one trematode and 12 potential Sarcocystis species through molecular genetic techniques. Infections with zoonotic Echinococcus multilocularis, Trichinella britovi and T. spiralis occurred as single cases. Per capita endoparasite species richness and diversity significantly increased with population size and changed with age, whereas sex, microsatellite heterozygosity, and geographic origin had no effect. Tapeworm abundance (Taenia spp.) was significantly higher in immigrants than natives. Metacestode prevalence was slightly higher in ungulates from wolf territories than from control areas elsewhere. Even though alternative canid definitive hosts might also play a role within the investigated parasite life cycles, our findings indicate that (1) immigrated wolves increase parasite diversity in German packs, and (2) prevalence of wolf-associated parasites had declined during wolf absence and has now risen during recolonisation.

Parasitofauna of Brown Bear (Ursus arctos) in the Protected Landscape Area CHKO — Poľana

Abstract During the years 2015—2016 we obtained 15 samples of faeces of brown bears (Ursus arctos) and 2 samples of gastrointestinal (GI) tracts of young female brown bears for helminthological examinations. The samples of faeces were collected from various sites in the protected landscape area CHKO-Poľana, and the gastrointestinal tracts originated from bears hunted down in the same area within permitted regulation of bear population for 2015. Of the 17 samples collected from the CHKO-Poľana area, 13 were positive for the presence of parasites (76.47 %). Parasitological examinations revealed the presence of 5 species of endoparasites: Eimeria, Cryptosporidium, Sarcocystis, Baylisascaris and Ancylostoma. Roundworms Baylisascaris transfuga (46.15 %) and Ancylostoma spp. (30.77 %) were the dominant species. Observation of the seasonal dynamics showed the highest prevalence of parasites during autumn and winter.

Epidemiology and geographical distribution of gastrointestinal parasitic infection in humans in Slovakia

Summary Examinations of the set of 2,760 samples of human stools revealed the current epidemiological situation in the occurrence of gastrointestinal parasitoses in Slovakia. Prevalence of gastrointestinal parasitic infection was P = 6.81 % out of which the protozoan infections was P = 2.64 % and helminthiases P = 4.17 %, in the representation of endoparasitic species Entamoeba coli, Giardia intestinalis, Blastocystis hominis, Endolimax nana, Ascaris lumbricoides, Trichuris trichiura and Enterobius vermicularis. The species with the highest proportion from the protozoa was Entamoeba coli (P = 0.79 %) and from the helminths Ascaris lumbricoides (P = 3.73 %). The highest prevalence of protozoan infections (P = 3.27 %) was found in the age group 8 – 18 yearly and helminthic infections (P = 5.84 %) in the lowest age group of children at the age of 1 month to 7 years. Almost regularly, there was most frequently infection with Endolimax nana, Giardia intestinalis and Ascaris lumbricoides. By comparison of all age categories, a high statistical significance of differences in the prevalence of helminthiases was found, which most frequently infected children aged from 1 month to 7 years (X2, p≤ 0.0001). The statistical significance of differences in the incidence of protozoan infections (X2, p≤ 0.01) and helminthiases (X2, p≤ 0.0001) was recorded between the compared regions of Slovakia (Western, Central and Eastern Slovakia) with the highest prevalence in the eastern region of Slovakia.

Description of a new endoparasitic copepod genus and species (Lamippidae) that induces gall formation in leaves of the sea pen Ptilosarcus gurneyi (Octocorallia) from British Columbia

A new genus and species of gall-forming endoparasitic copepod of the family Lamippidae is described from the orange sea pen Ptilosarcus gurneyi (Gray, 1860) collected in British Columbia, Canada. Lamippid copepods (over 50 species) are obligate endoparasites, some of which form galls in a variety of soft corals (Alcyonacea and Pennatulacea). Ptilosarcoma athyrmata n. gen., n. sp. is the first lamippid formally described from any species of Ptilosarcus Verrill, 1865. In total, 143 galls from six sea pens were dissected and found to typically contain one female and male copepod pair. Infested leaves of P. gurneyi had 1.4 ± 0.6 (n = 143) galls per leaf. Using light and scanning electron microscopy, the copepods were examined and found to most closely resemble those belonging to the genus Isidicola Gravier, 1914, based on the presence of maxillipeds and lack of acicules on the caudal rami; however, they are distinct from the sole species of Isidicola based on aspects of antennal morphology. We conclude that Lamippina laubieri Bouligand, 1960 is a synonym of L. aciculifera (Zulueta, 1908), thus the family presently contains 52 species and one subspecies. A key to lamippid genera and a table of all lamippid genera and species with all known hosts and locality records are provided.

Morphophysiological and cuticular chemical alterations caused by Xenos entomophagus endoparasites in the social wasp Polistes ferreri (Hymenoptera, Vespidae).

Social wasps can face many challenges during their colony cycle, including the presence of parasites. The order Strepsiptera is among the main parasites of the wasp genus Polistes. The aim of this study was to evaluate the effect of an endoparasite species on the host Polistes ferreri, with the hypothesis that females of this social wasp would undergo morphophysiological alterations as well as changes in their cuticular chemical profile caused by the obligate endoparasite. On average, parasitism was found in 10% of the colonies studied. All the parasitized females showed filamentous ovarioles without developing oocytes, which indicates a physiological castration. Moreover, the endoparasites present in the gaster of females caused its volume to increase, and the presence of endoparasites changed the cuticular chemical profiles of females, confirming our hypothesis. It is likely that this parasitism effect could hamper the maintenance of wasp colonies.

Gastrointestinal helminths and external parasites of domestic rats trapped from residential areas within Maiduguri Municipality, Nigeria

A survey of domestic rats was conducted to investigate the prevalence of gastrointestinal helminths and external parasites in Maiduguri municipal between February and June 2015. Rats were randomly collected from residential sites within Maiduguri metropolis by trapping using mechanical and glue board traps. Trapped rats were examined for external parasites, humanely sacrificed and subjected to detailed postmortem examination for recovery of gastrointestinal helminths using standard methods. Parasites were identified using key morphological characteristics. Out of 85 rats sampled in the study, a total of 7(8.2%) were positive for gastrointestinal helminths. The only species of helminth identified was Hymenolepis diminuta. There was no significant difference in prevalence of gastrointestinal helminths among different age groups and sexes (P>0.05). The overall prevalence of ectoparasites was 9.4% and there was no significant difference in prevalence rates among different age groups and sexes (P>0.05). The prevalence of flea (5.9%) was higher than lice (3.5%). The two species of ectoparasites identified in the study were Ctenocephalides canis (5.9%) and Polyplax spinulosa (3.5%). It was concluded from this study that domestic rats trapped from Maiduguri harbor some species of endoparasites and ectoparasites which are potentially zoonotic or may serve as vectors of important zoonotic pathogens.Keywords: Domestic rats, Ecto-parasites, Gastrointestinal helminths, Maiduguri, Prevalence

Non-invasive genetic sampling reveals diet shifts, but little difference in endoparasite richness and faecal glucocorticoids, in Belizean felids inside and outside protected areas

Abstract:Many Neotropical felids are threatened with extinction due to direct effects of habitat destruction and/or human persecution. However, indirect and synergistic effects of human-felid conflict remain under-studied and potentially include increased stress and diet shifts that may negatively impact felid health. We hypothesized that faecal glucocorticoid metabolites (FGM) and endoparasite species richness (ESR) would be higher, and diet would shift, for felids outside protected areas where conflict occurs. In north-western Belize, a scat-detector dog located 336 faecal samples, identified to species and individual using DNA analyses. DNA amplification success was substantially higher within protected areas than outside. We detected jaguar, puma, ocelot, jaguarundi and domestic cat. FGMs were higher in puma and jaguarundi than in other felids, while ESR was similar across felids with domestic cats exhibiting the highest number of genera. Diet partitioning occurred among felids, but domestic cats may compete with ocelot and jaguarundi for small prey. Outside of protected areas, large cats shifted their diet to smaller prey and livestock remains were not found. Contrary to our hypotheses, FGM and ESR did not differ inside versus outside protected areas, but sample sizes were low in human-modified areas. We provide a baseline on wild felid adrenal activity, endoparasites and diet and suggest improvements to increase sample sizes outside protected areas. Our research provides a template for expanding non-invasive sampling approaches more widely across the range of Neotropical felids.

Gastrointestinal parasites of maned wolf (Chrysocyon brachyurus, Illiger 1815) in a suburban area in southeastern Brazil

We examined 42 maned wolf scats in an unprotected and disturbed area of Cerrado in southeastern Brazil. We identified six helminth endoparasite taxa, being Phylum Acantocephala and Family Trichuridae the most prevalent. The high prevalence of the Family Ancylostomatidae indicates a possible transmission via domestic dogs, which are abundant in the study area. Nevertheless, our results indicate that the endoparasite species found are not different from those observed in protected or least disturbed areas, suggesting a high resilience of maned wolf and their parasites to human impacts, or a common scenario of disease transmission from domestic dogs to wild canid whether in protected or unprotected areas of southeastern Brazil.

Patterns of parasitism in the cooperatively breeding meerkat: a cost of dominance for females

Within animal societies, demographic and social factors, as well as the different reproductive efforts of group members, may influence individual patterns of reproductive success and parasitism. In mammals, such relationships have been studied primarily in male-dominant species. To better understand these linkages in other social systems, we studied a female-dominant cooperative breeder, the meerkat (Suricata suricatta). This species is characterized by intense intrasexual competition and extreme reproductive skew in both sexes. Within adults, we examined heterogeneities in infection by 6 species of endoparasites in relation to host factors (e.g., weight, age, social status, sex, and group size). We explored potential trade-offs between reproduction and parasitism in dominant and subordinate animals of both sexes. Whereas weight and age were predictive of a few parasite taxa, social status or sex predicted parasite species richness and patterns of infection for the majority of parasites examined. Moreover, a significant interaction between sex and status for 2 nematode taxa revealed that dominant females were the most at risk of infection. Lastly, a positive relationship between group size and parasitism was evident in females only. In sum, compared with subordinates, dominant meerkats may experience increased exposure to directly transmitted parasites. Coupled with hormone-mediated immunosuppression, the increased susceptibility of dominant females may reflect energy allocation for preferentially maintaining dominance and breeding status over parasite defense. In species in which female intrasexual competition is intense, this trade-off between reproduction and health may be more pronounced in females than in males.

Description of four new endoparasitic species of the family Splanchnotrophidae (Copepoda, Poecilostomatoida) from nudibranch and sacoglossan gastropod hosts

The Splanchnotrophidae are a worldwide-distributed family of endoparasitic copepods, utilising shell-less opisthobranch gastropod hosts. Using scanning electron microscopy, we describe three new Ismaila Bergh, 1867 species infesting nudibranch hosts from southern Chile. Ismaila volatilis spec. nov. infests the proctonotid Janolus sp. and differs from all congeners by the size and number of dorsal bulges, the number of processes on the maxilla, and the thickness of thoracic appendages. Ismaila chaihuiensis spec. nov. was found in the doridoidean Diaulula punctuolata (D’Orbigny, 1837) and is diagnosed by a pore situated on a prominent bulge above the labrum. Ismaila genalis spec. nov. from a polycerid Holoplocamus papposus Odhner, 1926 host differs from its congeners in the size and form of the ventral bulges present on the head. These discoveries further broaden the range of splanchnotrophid host taxa; they are in line with earlier hypotheses of strict host specificity of Ismaila species and support Chile as a hotspot for Ismaila radiation. Herein, we present a key to the identification of all 14 Ismaila species. In Sulawesi (tropical Indo-West Pacific), Arthurius gibbosa spec. nov. infests the sacoglossan Elysia macnaei Marcus, 1982. The new species differs from both congeners by the short and stubby dorsal bulges. Uniquely among splanchnotrophids, long thoracic appendages are absent. Arthurius Huys, 2001 thus is the morphologically most divergent genus of the Splanchnotrophidae, but it is well characterized by the loss of several mouthparts and the preference for sacoglossan hosts. Currently, the distribution of the genus is limited to the Indo-West Pacific.

New records of parasites in free-ranging Andean bears from Peru

Abstract I analyzed 28 fecal samples from Andean bears (Tremarctos ornatus) collected between 2003 and 2007 from the Laquipampa Wildlife Refuge and Yanachaga Chemillen National Park, Peru. I used the direct faeces test and spontaneous sedimentation tube technique to detect cysts, ova, and larvae. To detect intestinal coccidia, I applied acid stain using the Ziehl–Neelsen modified method. I detected parasites in 16 scats (57.1%), identifying 3 protozoa for the first time in the Andean bear: Blastocystis sp., Cryptosporidium sp., and Giardia sp.; as well as 3 nematodes: Strongyloides sp., an undetermined species of Ascarididae, and Ancylostomatidae. The greatest prevalence of parasites were of the family Strongyloididae (25.0%), followed by Ascarididae (21.4%), and Cryptosporidiidae (14.3%). Parasites were found in a greater percentage of scats collected during the dry season (87.5%) compared with the rainy season (16.7%). Overall, 8 species of endoparasites and 1 species of ectoparasite have been identifie...

Fine structure and cellular responses at the host–parasite interface in a range of fish–helminth systems

A series of ultrastructural-based studies were conducted on the interface region in different fish–helminth systems: (a) an intestinal infection of the cestode Monobothrium wageneri in tench, Tinca tinca; (b) an extensive intestinal submucosa and mucosal infection in tench by metacercariae of an unidentified digenean trematode; (c) an intestinal infection in brown trout, Salmo trutta, by the acanthocephalan Dentitruncus truttae; (d) an extraintestinal infection by larvae of the acanthocephalan, Pomphorhynchus laevis in three-spined sticklebacks, Gasterosteus aculeatus; and (e) an infection in the livers of Eurasian minnow, Phoxinus phoxinus, by larvae of the nematode Raphidascaris acus. Endoparasitic helminths frequently cause inflammation of the digestive tract and associated organs, inducing the recruitment of various immune cells to the site of infection. In each of the fish–helminth systems that were studied, a massive hyperplastic granulocyte response involving mast cells (MCs) and neutrophils in close proximity to the helminths was documented. The current study presents data on the interface region in each fish–helminth system and documents the penetration of mast cells granules within the tegument of P. laevis larvae. No extracellular vesicles containing tegumental secretions from any of the four different taxa of endoparasitic helminths species at the host–parasite interface region were seen.

Different parasite faunas in sympatric populations of sister hedgehog species in a secondary contact zone.

Providing descriptive data on parasite diversity and load in sister species is a first step in addressing the role of host-parasite coevolution in the speciation process. In this study we compare the parasite faunas of the closely related hedgehog species Erinaceus europaeus and E. roumanicus from the Czech Republic where both occur in limited sympatry. We examined 109 hedgehogs from 21 localities within this secondary contact zone. Three species of ectoparasites and nine species of endoparasites were recorded. Significantly higher abundances and prevalences were found for Capillaria spp. and Brachylaemus erinacei in E. europaeus compared to E. roumanicus and higher mean infection rates and prevalences for Hymenolepis erinacei, Physaloptera clausa and Nephridiorhynchus major in E. roumanicus compared to E. europaeus. Divergence in the composition of the parasite fauna, except for Capillaria spp., which seem to be very unspecific, may be related to the complicated demography of their hosts connected with Pleistocene climate oscillations and consequent range dynamics. The fact that all parasite species with different abundances in E. europaeus and E. roumanicus belong to intestinal forms indicates a possible diversification of trophic niches between both sister hedgehog species.

Diversity, distribution and nature of faunal associations with deep-sea pennatulacean corals in the Northwest Atlantic.

Anthoptilum grandiflorum and Halipteris finmarchica are two deep-sea corals (Octocorallia: Pennatulacea) common on soft bottoms in the North Atlantic where they are believed to act as biogenic habitat. The former also has a worldwide distribution. To assist conservation efforts, this study examines spatial and temporal patterns in the abundance, diversity, and nature of their faunal associates. A total of 14 species were found on A. grandiflorum and 6 species on H. finmarchica during a multi-year and multi-site sampling campaign in eastern Canada. Among those, 7 and 5 species, respectively, were attached to the sea pens and categorized as close associates or symbionts. Rarefaction analyses suggest that the most common associates of both sea pens have been sampled. Biodiversity associated with each sea pen is analyzed according to season, depth and region using either close associates or the broader collection of species. Associated biodiversity generally increases from northern to southern locations and does not vary with depth (∼100–1400 m). Seasonal patterns in A. grandiflorum show higher biodiversity during spring/summer due to the transient presence of early life stages of fishes and shrimps whereas it peaks in fall for H. finmarchica. Two distinct endoparasitic species of highly modified copepods (families Lamippidae and Corallovexiidae) commonly occur in the polyps of A. grandiflorum and H. finmarchica, and a commensal sea anemone frequently associates with H. finmarchica. Stable isotope analyses (δ13C and δ15N) reveal potential trophic interactions between the parasites and their hosts. Overall, the diversity of obligate/permanent associates of sea pens is moderate; however the presence of mobile/transient associates highlights an ecological role that has yet to be fully elucidated and supports their key contribution to the enhancement of biodiversity in the Northwest Atlantic.

Endoparasites of some economically important food fishes of River Jhelum, Kashmir (India).

During the present study endo-parasitic fauna of fish at different sites of River Jhelum were analysed. Four different species of endoparasites were recovered from Schizothorax species which include Adenoscolex kashmirensis Mehra, 1930, Bothriocephalus acheilognathi Yamaguti, 1934, Echinorhynchus sp., Pomphorhynchus kashmirensis Kaw, 1941, belong to Phylum Platyhelminths and Phylum Acanthocephala. Prevalence and generation time were inversely proportional to each other. Prevalence and mean abundance were highest at Qamarwari. Diversity was more at Tengpora. Cestodes including Adenoscolex kashmirensis and Bothriocephalus acheilognathi were more dominant than Pomphorhynchus kashmirensis and Echinorhynchus sp.

Golfingicola abyssalis gen. et sp. nov., a new endoparasitic copepod (Crustacea) in a sipunculan from abyssal depths of the Northwest Pacific Ocean

Marine copepods, which inhabit the entire water column down to the seafloor, are key contributors to the food web, mainly providing a food source for many organisms in the form of zooplankton. Furthermore, they also play an important ecological role as associates or even parasites with various degrees of harm to their hosts. Copepods are found in almost all habitats and can be associated with virtually every metazoan group. A female and four males of a new endoparasitic copepod genus and species (Golfingicola abyssalis) are described from the trunk celom of the sipunculan Golfingia muricaudata (Southern, 1913), collected from the abyssal depths of the Northwest Pacific Ocean near the Kuril–Kamchatka Trench. This sipunculan species is a typical deep sea representative of the northwestern Pacific region, occurring in the Bering Sea and the abyssal regions east of the Kuril Island chain. Despite numerous records of this species, a copepod association has not been reported prior to this paper. The new parasitic copepod species is tentatively placed in the Akessonia group given its endoparasitic behavior in Sipuncula, the elongated shape, the enlarged egg strings, and the presence of subchelate antenna, as well as lateral processes in males. Golfingicola abyssalis, however, shows some peculiarities that clearly differentiate it from the remaining endoparasites in Sipuncula. As the first abyssal endoparasite in Sipuncula, the species is characterized by the complete lack of any processes in females, the presence of a mandible in females, a weakly defined prosome–urosome boundary in females, the presence of a mouth in males, the free living behavior of males, a distinctly reduced number of trunk processes in males, as well as a more modified male antenna, displaying an endopodite and a highly modified setal element. A detailed review on the morphological characters of the four species currently grouped in the Akessonia group, and systematic and biogeographic information of their relevant host taxa is provided. On the basis of morphological and ecological similarities, the new species seems to be more closely related to the northern Atlantic Akessonia occulta Bresciani and Luetzen, 1962 than to Siphonobius gephyreicola Augener, 1903 and Coelotrophus nudus Ho et al., 1981.