Two New Species of Sucking Lice (Psocodea: Phthiraptera: Hoplopleuridae) from Chestnut Mice, Pseudomys gracilicaudatus and Pseudomys nanus (Rodentia: Muridae), in Australia.

We describe two new species of sucking lice in the genus Hoplopleura Enderlein, 1904 (Psocodea: Phthiraptera: Hoplopleuridae) from Australia: Hoplopleura gracilicaudatusa n. sp. from the eastern chestnut mouse Pseudomys gracilicaudatus (Gould) (Rodentia: Muridae), and Hoplopleura nanusa n. sp. from the western chestnut mouse Pseudomys nanus (Gould) (Rodentia: Muridae). Pseudomys Gray is the most speciose genus of rodents endemic to Australia with 24 species; however, only two Pseudomys species have been reported previously to be hosts of sucking lice. The description of the new species in the present study doubles the number of sucking louse species known to parasitize Pseudomys mice and increases the total number of sucking louse species known from endemic Australian rodents from 21 to 23. Pseudomys gracilicaudatus and P. nanus are closely related murines that diverged ~1 MYA with distinct and widely separated extant geographic distributions. The two new Hoplopleura species described in the present study share some morphological characters and likely co-evolved and co-speciated with their chestnut mouse hosts.

Disentangling lousy relationships: Comparative phylogenomics of two sucking louse lineages parasitizing chipmunks.

The evolution of obligate parasites is often interpreted in light of their hosts' evolutionary history. An expanded approach is to examine the histories of multiple lineages of parasites that inhabit similar environments on a particular host lineage. Western North American chipmunks (genus Tamias) have a broad distribution, a history of divergence with gene flow, and host two species of sucking lice (Anoplura), Hoplopleura arboricola and Neohaematopinus pacificus. From total genomic sequencing, we obtained sequences of over 1100 loci sampled across the genomes of these lice to compare their evolutionary histories and examine the roles of host association in structuring louse relationships. Within each louse species, clades are largely associated with closely related chipmunk host species. Exceptions to this pattern appear to have a biogeographic component, but differ between the two louse species. Phylogenetic relationships among these major louse clades, in both species, are not congruent with chipmunk relationships. In the context of host associations, each louse lineage has a different evolutionary history, supporting the hypothesis that host-parasite assemblages vary both across the landscape and with the taxa under investigation. In addition, the louse Hoplopleura erratica (parasitizing the eastern Tamias striatus) is embedded within H. arboricola, rendering it paraphyletic. This phylogenetic result, together with comparable divergences within H. arboricola, indicate a need for taxonomic revision. Both host divergence and biogeographic components shape parasite diversification as demonstrated by the distinctive diversification patterns of these two independently evolving lineages that parasitize the same hosts.

Identification of Lice Stored in Alcohol Using MALDI-TOF MS.

Lice pose major public and veterinary health problems with economic consequences. Their identification is essential and requires the development of an innovative strategy. MALDI-TOF MS has recently been proposed as a quick, inexpensive, and accurate tool for the identification of arthropods. Alcohol is one of the most frequently used storage methods and makes it possible to store samples for long periods at room temperature. Several recent studies have reported that alcohol alters protein profiles resulting from MS analysis. After preliminary studies on frozen lice, the purpose of this research was to evaluate the influence of alcohol preservation on the accuracy of lice identification by MALDI-TOF MS. To this end, lice stored in alcohol for variable periods were submitted for MS analysis and sample preparation protocols were optimized. The reproducibility and specificity of the MS spectra obtained on both these arthropod families allowed us to implement the reference MS spectra database (DB) with protein profiles of seven lice species stored in alcohol. Blind tests revealed a correct identification of 93.9% of Pediculus humanus corporis (Linnaeus, 1758) and 98.4% of the other lice species collected in the field. This study demonstrated that MALDI-TOF MS could be successfully used for the identification of lice stored in alcohol for different lengths of time.

Eight New Species of Sucking Lice (Psocodea: Phthiraptera) From Endemic Murine Rodents in Australia and an Updated Identification Key.

Based on a comprehensive study of museum specimens, eight new species of sucking lice of the genus Hoplopleura Enderlein, 1904 (Psocodea: Phthiraptera: Hoplopleuridae), are described from six genera of Australian Old Endemic rodents: Conilurus Ogilby, 1838 (Rodentia: Muridae), Leggadina Thomas, 1910 (Rodentia: Muridae), Leporillus Thomas, 1906 (Rodentia: Muridae), Mesembriomys Palmer, 1906 (Rodentia: Muridae), Pogonomys Milne-Edwards, 1877 (Rodentia: Muridae), and Xeromys Thomas, 1889 (Rodentia: Muridae). The description of these new species increases the number of sucking louse species from endemic Australian rodents from 13 to 21 and extends the records of sucking lice to all of the 14 genera of endemic rodents in Australia. Our results show that sucking lice are much more diverse among rodents in Australia than previously known. Furthermore, the Australian Hoplopleura species are host specific-each Hoplopleura species, including the eight new species described in the present study, parasitizes only a single host species, except Hoplopleura irritans Kuhn and Ludwig, 1967 (Psocodea: Phthiraptera: Hoplopleuridae) and Hoplopleura melomydis Weaver, 2017 (Psocodea: Phthiraptera: Hoplopleuridae), each of which is found on two host species. An updated dichotomous key for identifying Australian Hoplopleura species is included.

Variation of mitochondrial minichromosome composition in Hoplopleura lice (Phthiraptera: Hoplopleuridae) from rats.

BACKGROUND: The family Hoplopleuridae contains at least 183 species of blood-sucking lice, which widely parasitize both mice and rats. Fragmented mitochondrial (mt) genomes have been reported in two rat lice (Hoplopleura kitti and H. akanezumi) from this family, but some minichromosomes were unidentified in their mt genomes. METHODS: We sequenced the mt genome of the rat louse Hoplopleura sp. with an Illumina platform and compared its mt genome organization with H. kitti and H. akanezumi. RESULTS: Fragmented mt genome of the rat louse Hoplopleura sp. contains 37 genes which are on 12 circular mt minichromosomes. Each mt minichromosome is 1.8-2.7 kb long and contains 1-5 genes and one large non-coding region. The gene content and arrangement of mt minichromosomes of Hoplopleura sp. (n = 3) and H. kitti (n = 3) are different from those in H. akanezumi (n = 3). Phylogenetic analyses based on the deduced amino acid sequences of the eight protein-coding genes showed that the Hoplopleura sp. was more closely related to H. akanezumi than to H. kitti, and then they formed a monophyletic group. CONCLUSIONS: Comparison among the three rat lice revealed variation in the composition of mt minichromosomes within the genus Hoplopleura. Hoplopleura sp. is the first species from the family Hoplopleuridae for which a complete fragmented mt genome has been sequenced. The new data provide useful genetic markers for studying the population genetics, molecular systematics and phylogenetics of blood-sucking lice.

Fragmented mitochondrial genomes evolved in opposite directions between closely related macaque louse Pedicinus obtusus and colobus louse Pedicinus badii.

We report for the first time the fragmented mitochondrial (mt) genomes of two Pedicinus species: Pedicinus obtusus and Pedicinus badii, and compared them with the lice of humans and chimpanzees. Despite being congeneric, the two monkey lice are distinct from each other in mt karyotype. The variation in mt karyotype between the two Pedicinus lice is the most pronounced among the congeneric species of sucking lice observed to date and is attributable to the opposite directions between them in mt karyotype evolution. Two of the inferred ancestral mt minichromosomes of the higher primate lice merged as one in the macaque louse whereas one of the ancestral minichromosomes split into two in the colobus louse after these two species diverged from their most recent common ancestor. Our results showed that mt genome fragmentation was a two-way process in the higher primate lice, and minichromosome merger was more common than previously thought.

Two New Species of Sucking Lice (Phthiraptera: Anoplura: Hoplopleuridae and Polyplacidae) from Grant's Rock Mouse, Micaelamys granti, in South Africa.

Two new species of sucking lice (Phthiraptera: Anoplura), Hoplopleura granti n. sp. (Hoplopleuridae) and Polyplax megacephalus n. sp. (Polyplacidae), are described from Grant's rock mouse, Micaelamys granti (Wroughton), from Northern Cape Province, South Africa. Adults of both sexes are illustrated via line drawings and differential interference contrast microscopy images, and are compared with previously described related species that parasitize related hosts: Hoplopleura patersoni Johnson from Aethomys chrysophilus (de Winton) (red veld rat), Aethomys kaiseri (Noack) (Kaiser's aethomys), and Micaelamys namaquensis (A. Smith) (Namaqua rock mouse); Hoplopleura aethomydis Kleynhans from M. namaquensis; Polyplax praomydis Bedford from A. chrysophilus and M. namaquensis; and Polyplax solivaga Johnson from A. chrysophilus. It is not known if these new species of lice are vectors of any pathogens.

A Case of Linognathus setosus (von Olfers, 1816) (Phthiraptera: Anoplura) Infestation in a Dog.

This case report was prepared to give information about Linognathus setosus (von Olfers, 1816) detected on a 2-year-old male Rottweiler breed dog which was brought to a private veterinary clinic due to restlessness and itching. Lice were found especially on the head, neck and back regions of the dog in the examination for ectoparasites. Four female, 2 male and 9 nymph lice were collected from dog. The collected lice were preserved in eppendorf tubes containing 70% ethanol (C2H5OH) and were sent to the Department of Parasitology, Faculty of Veterinary Medicine Selçuk University for species identification. In the laboratory, the lice were left to be transparent in a 10% potassium hydroxide solution and passed through a series of alcohols (70% - 99% ethanol), glued onto the slide with Canadian balsam and examined microscopically. Lice were identified as L. setosus. Although this species has been reported in Turkey, there is no article about its morphological structure, biology and prevalence. Therefore, detailed informations about the morphological features of L. setosus are given to inform veterinarians and scientists working in this field.

Development of MALDI-TOF mass spectrometry for the identification of lice isolated from farm animals.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now routinely used for the rapid identification of microorganisms isolated from clinical samples and has been recently successfully applied to the identification of arthropods. In the present study, this proteomics tool was used to identify lice collected from livestock and poultry in Algeria. The MALDI-TOF MS spectra of 408 adult specimens were measured for 14 species, including Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus, Menacanthus stramineus, Menopon gallinae, Chelopistes meleagridis, Goniocotes gallinae, Goniodes gigas, Lipeurus caponis and laboratory reared Pediculus humanus corporis. Good quality spectra were obtained for 305 samples. Spectral analysis revealed intra-species reproducibility and inter-species specificity that were consistent with the morphological classification. A blind test of 248 specimens was performed against the in-lab database upgraded with new spectra and validated using molecular tools. With identification percentages ranging from 76% to 100% alongside high identification scores (mean = 2.115), this study proposes MALDI-TOF MS as an effective tool for discriminating lice species.

TITLE: Développement de la spectrométrie de masse MALDI-TOF MS pour l'identification de poux isolés d'animaux de ferme. ABSTRACT: La Spectrométrie de Masse à Temps de Vol par Désorption/Ionisation Laser Assistée après Matrice est maintenant utilisée pour l'identification rapide des microorganismes isolés à partir d'échantillons cliniques et a récemment été appliquée avec succès pour l'identification des arthropodes. Dans cette étude, cet outil protéomique a été utilisé pour identifier les poux prélevés sur le bétail et la volaille en Algérie. Les spectres MALDI-TOF MS de 408 spécimens adultes ont été mesurés pour 14 espèces, dont Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus, Menacanthus stramineus, Menopon gallinae, Chelopistes meleagridis, Goniocotes gallinae, Goniodes gigas, Lipeurus caponis et Pediculus humanus corporis élevé en laboratoire. Des spectres de bonne qualité ont été obtenus pour 305 échantillons. L'analyse spectrale a révélé une reproductibilité intra-espèce et une spécificité inter-espèces qui concordaient avec la classification morphologique. Un test à l'aveugle de 248 échantillons a été effectué par rapport à la base de données de notre laboratoire mise à niveau avec de nouveaux spectres et validée à l'aide d'outils moléculaires. Avec des pourcentages d'identification allant de 76 à 100 % et des scores d'identification élevés (moyenne : 2,115), cette étude propose MALDI-TOF MS comme un outil efficace pour distinguer les espèces de poux.

A New Species of Sucking Louse from the Mandrill from Gabon with a Review of Host Associations and Geographical Distributions, and Identification Keys to Members of the Genus pedicinus (Phthiraptera: Anoplura: Pedicinidae).

Members of the sucking louse genus Pedicinus are ectoparasites of cercopithecid primates in Africa, Asia, and Gibraltar. Pedicinus gabonensis n. sp. is described on the basis of adult male and female specimens collected from the mandrill (Mandrillus sphinx) in Gabon. The new species is compared morphologically with other members of the genus Pedicinus, and a nuclear elongation factor 1 alpha gene sequence is provided. Host associations and geographical distributions of the 18 previously recognized species of the genus and of P. gabonensis n. sp. are reviewed. Updated identification keys are provided for males and females of all known valid species of Pedicinus.

Annotated checklist of fleas (Insecta: Siphonaptera) and lice (Insecta: Anoplura) associated with rodents in Iran, with new reports of fleas and lice.

BACKGROUND & OBJECTIVES: Rodent species reported from Iran are subject of several studies, but the fauna called ectoparasite, infesting the rodents, along with their epidemic effects, are poorly known. In this study, ectoparasitic insect fauna of rodents found across the Iran were studied, to generate an annotated checklist of fleas and lice species. METHODS: Several field expeditions focused on different habitats of northeastern Iran were conducted between January 2017 and May 2018. Rodent trapping was carried out using custom-made mesh live traps and "Faragir" live traps baited mainly with scorched sunflower and gourd seeds. The trapped rodents were examined for ectoparasites on their body, and then released at their trapping point. The rodents and ectoparasite species were identified based on available keys. RESULTS: A total of 217 rodents belonging to 16 species of the families Calomyscidae, Cricetidae, Dipodidae, Mu- ridae and Sciuridae were captured. Five species of each fleas and lice were collected from the body of the trapped rodents. Three flea species, Ctenophthalmus pseudagyrtes, Nosopsyllus iranus and Xenopsylla buxtoni; and two louse species, Polyplax gerbilli and P. spinulosa, were recorded for the first time. INTERPRETATION & CONCLUSION: The study generated an annotated checklist of 79 species of fleas and 8 species of lice harboured by different species of rodents distributed in Iran which would be helpful in different taxonomic studies such as parasite-host coevolution, and also sanitation and health monitoring programs.

A New Species of Sucking Louse from the Long-tailed Ground Squirrel, Urocitellus undulatus, from Mongolia, with a Key to Species, and a Review of Host Associations and Geographical Distributions of Members of the Genus Linognathoides (Psocodea: Anoplura: Polyplacidae).

Members of the genus Linognathoides are ectoparasites of ground squirrels and marmots (Rodentia: Sciuridae) in the Nearctic, Palearctic, and Afrotropical regions. Linognathoides urocitelli n. sp. is described based on adult male and female and third-instar nymphal specimens collected from the long-tailed ground squirrel (Urocitellus undulatus) in Mongolia. The new species is compared morphologically to other members of the genus Linognathoides. Additionally, DNA sequences of a 610-base pair (bp) fragment of the nuclear 18S rDNA gene, a 452-bp fragment of the mitochondrial 12S rrnS gene, and a 363-bp fragment of the mitochondrial 16S rrnL gene are provided. Host associations and geographical distributions of the 11 previously recognized species of the genus, and of Linognathoides urocitelli n. sp., are reviewed. A dichotomous identification key to adults of all known species in the genus Linognathoides is provided.

Antarctophthirus microchir infestation in synanthropic South American sea lion (Otaria flavescens) males diagnosed by a novel non-invasive method.

Antarctophthirus microchir is a sucking louse species belonging to the family Echinophthiriidae and has been reported to parasitize all species of the subfamily Otariinae, the sea lions. Former studies on this ectoparasite mainly required fixation, immobilization, or death of host species and especially examinations of adult male sea lions are still very rare. Between March and May 2018, adult individuals of a unique "urban" bachelor group of South American sea lions (Otaria flavescens) living directly in the city of Valdivia, Chile, were studied regarding their ectoparasite infestation status. For first time, a non-invasive method in the form of a lice comb screwed on a telescopic rod and grounded with adhesive tape was used for sample taking process. Overall, during combing different stages of A. microchir were detected in 4/5 O. flavescens individuals, especially at the junction between the back and hind flippers. Our findings represent the first report of A. microchir infesting individuals of this synanthropic colony and fulfilling complete life cycle in a sea lion group despite inhabiting freshwater and in absence of females/pups. Our "telescopic lice comb apparatus" offers a new strategy to collect different stages of ectoparasites and a range of epidermal material, such as fur coat hair and superficial skin tissue for a broad spectrum of research fields in wildlife sciences in an unmolested and stress reduced manner.

Mitochondrial Genome Fragmentation Unites the Parasitic Lice of Eutherian Mammals.

Organelle genome fragmentation has been found in a wide range of eukaryotic lineages; however, its use in phylogenetic reconstruction has not been demonstrated. We explored the use of mitochondrial (mt) genome fragmentation in resolving the controversial suborder-level phylogeny of parasitic lice (order Phthiraptera). There are approximately 5000 species of parasitic lice in four suborders (Amblycera, Ischnocera, Rhynchophthirina, and Anoplura), which infest mammals and birds. The phylogenetic relationships among these suborders are unresolved despite decades of studies. We sequenced the mt genomes of eight species of parasitic lice and compared them with 17 other species of parasitic lice sequenced previously. We found that the typical single-chromosome mt genome is retained in the lice of birds but fragmented into many minichromosomes in the lice of eutherian mammals. The shared derived feature of mt genome fragmentation unites the eutherian mammal lice of Ischnocera (family Trichodectidae) with Anoplura and Rhynchophthirina to the exclusion of the bird lice of Ischnocera (family Philopteridae). The novel clade, namely Mitodivisia, is also supported by phylogenetic analysis of mt genome and cox1 gene sequences. Our results demonstrate, for the first time, that organelle genome fragmentation is informative for resolving controversial high-level phylogenies.

Prevalence and risk factors associated with ectoparasite infestation of buffaloes in an Amazonian ecosystem.

BACKGROUND: The water buffalo (Bubalus bubalis) is well adapted in some regions of the Amazon. Of all Brazilian states, Pará contains the largest number of this species, with 510,000 animals, approximately 38% of the Brazilian buffaloes. Despite the socioeconomic importance of bubaline farming in the northern region, little is known about the prevalence of ectoparasites that affect buffalo herds. This study aimed to identify the species of buffalo ectoparasites in the municipality of Santarém, Pará, and to determine possible risk factors related to ectoparasitic infestation. A cross-sectional study was conducted by sampling 60 rural properties and 621 buffaloes for ectoparasites. When present, ectoparasites were collected for subsequent identification. RESULTS: Of all the animals sampled, 18.5% (115/621) had ectoparasites, 7.8% (49/621) had ticks from the species Rhipicephalus (Boophilus) microplus and Amblyomma cajennense (sensu stricto), and 11.5% (72/621) had lice from the Haematopinus tuberculatus species. Six animals presented mixed infestations of ticks and lice. Among the sampled farms, 51.6% (31/60) had at least one animal infested with ectoparasites. The prevalence of ticks and lice on buffaloes was associated with the farm site, with higher prevalence (11.5% ticks, 15.4% lice) in animals at dry land (OR: 16.7 and 5.7 for ticks and lice, respectively) when compared with floodplains (0.5% ticks, 3.4% lice). Buffaloes aged 1 to 12 months had more ticks whereas buffaloes aged 13 to 24 months had more lice (P < 0.05). CONCLUSIONS: Buffaloes bred in the municipality of Santarém present different levels of tick and lice infestation according to the direct influence of Amazon ecosystem characteristics. The floodplain environment, widely used for buffalo farming, contributes toward minor ectoparasite infestations in these animals.

A New Species of Sucking Louse (Phthiraptera: Anoplura: Polyplacidae) From the Gray Mouse Lemur, Microcebus murinus (Primates: Cheirogaleidae), in Madagascar.

Lemurpediculus madagascariensis sp. nov. (Phthiraptera: Anoplura: Polyplacidae) is described from the Gray Mouse lemur, Microcebus murinus (J. F. Miller) (Primates: Cheirogaleidae), from Ankarafantsika National Park, Madagascar. Lemurs were trapped using Sherman Live Traps and visually inspected for lice, which were preserved in 90% ethanol. Adults of both sexes and the third-instar nymph of the new species are illustrated and distinguished from the four previously known species of Lemurpediculus: L. verruculosus (Ward); L. petterorum Paulian; L. claytoni Durden, Blanco, and Seabolt; and L. robbinsi Durden, Blanco, and Seabolt. It is not known if the new species of louse is a vector of any pathogens or parasites.

Two New Species of Sucking Lice (Phthiraptera: Anoplura: Polyplacidae) From Endangered, Hibernating Lemurs (Primates: Cheirogaleidae).

Lemurpediculus robbinsi sp. nov. is described from Crossley's dwarf lemur, Cheirogaleus crossleyi A. Grandidier, and Lemurpediculus claytoni sp. nov. is described from Sibree's dwarf lemur, Cheirogaleus sibreei Forsyth Major, from Madagascar. Both sexes of each new louse species are illustrated and distinguished from the two previously known species of Lemurpediculus: L. verruculosus (Ward) and L. petterorum Paulian. With the addition of two new species to the genus, an amended description of Lemurpediculus is provided. The two hosts of the new louse species are morphologically similar, endangered, obligately hibernating lemurs. These two species of lemurs are sometimes sympatric in rainforests in eastern Madagascar. Despite the morphological similarity of the two host species, their lice are morphologically distinct and are easiest to identify based on the shape of the subgenital plate of the female and the shape of the genitalia in the male. Both new species of lice should be considered to be endangered because their hosts are endangered. It is not known if either of the new species of lice are vectors of pathogens or parasites to their hosts.

The Mitochondrial Genome of the Guanaco Louse, Microthoracius praelongiceps: Insights into the Ancestral Mitochondrial Karyotype of Sucking Lice (Anoplura, Insecta).

Fragmented mitochondrial (mt) genomes have been reported in 11 species of sucking lice (suborder Anoplura) that infest humans, chimpanzees, pigs, horses, and rodents. There is substantial variation among these lice in mt karyotype: the number of minichromosomes of a species ranges from 9 to 20; the number of genes in a minichromosome ranges from 1 to 8; gene arrangement in a minichromosome differs between species, even in the same genus. We sequenced the mt genome of the guanaco louse, Microthoracius praelongiceps, to help establish the ancestral mt karyotype for sucking lice and understand how fragmented mt genomes evolved. The guanaco louse has 12 mt minichromosomes; each minichromosome has 2-5 genes and a non-coding region. The guanaco louse shares many features with rodent lice in mt karyotype, more than with other sucking lice. The guanaco louse, however, is more closely related phylogenetically to human lice, chimpanzee lice, pig lice, and horse lice than to rodent lice. By parsimony analysis of shared features in mt karyotype, we infer that the most recent common ancestor of sucking lice, which lived ∼75 Ma, had 11 minichromosomes; each minichromosome had 1-6 genes and a non-coding region. As sucking lice diverged, split of mt minichromosomes occurred many times in the lineages leading to the lice of humans, chimpanzees, and rodents whereas merger of minichromosomes occurred in the lineage leading to the lice of pigs and horses. Together, splits and mergers of minichromosomes created a very complex and dynamic mt genome organization in the sucking lice.

A new species of sucking louse (Phthiraptera: Anoplura: Linognathidae) from Günther's Dikdik (Madoqua guentheri) in Kenya.

Linognathus samburi n. sp. is described from adult male and female specimens collected from a juvenile female Günther's dikdik (Madoqua guentheri) live-trapped near Olturot Village, Samburu district (Rift Valley Province) in northern Kenya. The new species is distinguished from other species of Linognathus including Linognathus geigyi and Linognathus damarensis, both of which parasitize Kirk's dikdik (Madoqua kirkii). A dichotomous key to the species of Linognathus that are known to parasitize dikdiks is included.

Antarctophthirus carlinii (Anoplura: Echinophthiriidae), a new species from the Weddell seal Leptonychotes weddelli.

As a part of an ongoing long-term study on the biology of pack-ice seals in Antarctica, we had the opportunity to collect lice from Weddell seals (Leptonychotes weddelli). We did not find the original description of this host-parasite association. Antarctophthirus ogmorhini had previously been reported as a parasite for the Weddell seal, but the information is, to a certain extent, confusing. During the development of the present study, we had access to literature concerning the presence of A. ogmorhini on this host, which, to our knowledge, was not determined in any of the previous works on this species. We compared lice collected from Weddell seals with A. ogmorhini obtained from the type host, the leopard seal (Hydrurga leptonyx), and we found that both species can be distinguished. The main differences are the characteristic pattern of chaetotaxy in the dorsal side of the head in lice from Weddell seals, the size and form of the pseudopenis, and the distribution and size of the fringe of setae surrounding the genital opening. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we proposed that lice from Weddell seals constitute a new species. In the present work, we described and illustrated adults of this new species collected from Weddell seals during the austral summer of 2014 at the Danco Coast, Antarctic Peninsula.