A revision of the genus Extenuipalpus Reck, 1959 (Trombidiformes: Tetranychoidea: Tenuipalpidae), with description of a new species.

Extenuipalpus is reviewed, covering its taxonomic history, a new genus diagnosis, body and leg chaetotaxy, and redescriptions of the three previously known species E. niekerkae (Meyer, 1979), E. quadrisetosus (Lawrence, 1940) and E. sagittus (Meyer, 1993) based on type material. We also describe a new species, E. situngu Beard & Ueckermann sp. nov. from glossy forest grape, Rhoicissus rhomboidea (E. Mey ex Harv.) Planch. (Vitaceae), and provide a key to species of Extenuipalpus.

The first cryptic genus of Ixodida, Cryptocroton n. gen. for Amblyomma papuanum Hirst, 1914: a tick of North Queensland, Australia, and Papua New Guinea.

We describe a new genus Cryptocroton n. gen. for Amblyomma papuanum Hirst, 1914, a tick of North Queensland, Australia, and Papua New Guinea.

Phoresy and Mites: More Than Just a Free Ride.

Mites are masters at attaching to larger animals, often insects, in a temporary symbiosis called phoresy that allows these tiny animals to exploit patchy resources. In this article, we examine phoresy in the Acari, including those that feed on their carriers in transit, from a broad perspective. From a phylogenetic perspective, phoresy has evolved several times from free-living ancestors but also has been lost frequently. Rotting logs appear to be the first patchy resource exploited by phoretic mites, but the evolution of rapid life cycles later permitted exploitation of short-lived resources. As phoresy is a temporary symbiosis, most species have off-host interactions with their carrier. These relationships can be highly complex and context dependent but often are exploitative of the carrier's resources or progeny. Transitions from phoresy to parasitism seem widespread, but evidence for transitions from obligate phoretic parasitism to permanent parasitism is weak.

A new subgenus, Australixodes n. subgen. (Acari: Ixodidae), for the kiwi tick, Ixodes anatis Chilton, 1904, and validation of the subgenus Coxixodes Schulze, 1941 with a phylogeny of 16 of the 22 subgenera of Ixodes Latreille, 1795 from entire mitochondrial genome sequences.

A new subgenus, Australixodes n. subgen., is described for the kiwi tick, Ixodes anatis Chilton, 1904. The subgenus Coxixodes Schulze, 1941 is validated for the platypus tick, Ixodes (Coxixodes) ornithorhynchi Lucas, 1846, sister group of the subgenus Endopalpiger Schulze, 1935. A phylogeny from mitochondrial genomes of 16 of the 22 subgenera of Ixodes (32 spp.) indicates, for the first time, the relationships of the subgenera of Ixodes Latreille, 1795, the largest genus of ticks.

Two New Phoretic Species of Heterostigmatic Mites (Acari: Prostigmata: Neopygmephoridae and Scutacaridae) on Australian Hydrophilid Beetles (Coleoptera: Hydrophilidae).

Many heterostigmatic mites (Acari: Prostigmata: Heterostigmata) display a wide range of symbiotic interactions, from phoresy to parasitism, with a variety of insects. Australia is expected to harbour a rich diversity of heterostigmatic mites; however, its phoretic fauna and its host associations remain mainly unexplored. We conducted a short exploration of Australian insect-associated phoretic mites in summer 2020 and found two new phoretic heterostigmatic species on a semiaquatic hydrophilid beetle species, Coelostoma fabricii (Montrouzier, 1860) (Coleoptera: Hydrophilidae). Here, we describe these two new species, Allopygmephorus coelostomus sp. nov. (Neopygmephoridae) and Archidispus hydrophilus sp. nov. (Scutacaridae), which both belong to the superfamily Pygmephoroidea. Both species are distinct from their congeners, with a plesiomorphic character, bearing a median genital sclerite (mgs). Our study reports both genera for the first time from Australia.

Rediscovery of Ixodes confusus in Australia with the first description of the male from Australia, a redescription of the female and the mitochondrial (mt) genomes of five species of Ixodes.

We: (i) report the rediscovery of Ixodes (Sternalixodes) confusus Roberts, 1960 in Australia; (ii) redescribe the male and female of I. confusus; (iii) describe the mitochondrial (mt) genome of I. confusus from five ticks from four localities in Far North Queensland; and (iv) present the first substantial phylogeny of the subgenera of the Ixodes. The mt genomes of I. confusus, I. cornuatus, I. hirsti, I. myrmecobii and I. trichosuri are presented here for the first time. In our phylogeny from entire mt genomes (ca. 15 kb), the subgenus Endopalpiger was the sister-group to subgenera Sternalixodes plus Ceratixodes plus Exopalpiger whereas Exopalpiger was the sister to Sternalixodes plus Ceratixodes. [i.e. ((Endopalpiger) (Sternalixodes, Ceratixodes and Exopalpiger))]. Finally, we show that Ixodes anatis, the kiwi tick, may be closely related to the ticks of marsupials of Australia and Papua New Guinea.

Description of the female, nymph and larva and mitochondrial genome, and redescription of the male of Ixodes barkeri Barker, 2019 (Acari: Ixodidae), from the short-beaked echidna, Tachyglossus aculeatus, with a consideration of the most suitable subgenus for this tick.

BACKGROUND: Ixodes barkeri, a tick with a distinctive ventrolateral horn-like projection on palpal segment 1, was described in 2019 from two male ticks from the Wet Tropics of Far North Queensland, Australia. However, females lie at the core of the taxonomy and subgenus classification of Ixodes; hence, we sought specimens of female ticks, successfully recovering females, plus nymphs and larvae. Mitochondrial genomes are also desirable additions to the descriptions of species of ticks particularly regarding subgenus systematics. So, we sequenced the mt genomes of I. barkeri Barker, 2019, and the possible relatives of I. barkeri that were available to us (I. australiensis Neumann, 1904, I. fecialis Warburton & Nuttall, 1909, and I. woyliei Ash et al. 2017) with a view to discovering which if any of the subgenera of Ixodes would be most suitable for I. barkeri Barker, 2019. RESULTS: The female, nymph, larva and mitochondrial genome of Ixodes barkeri Barker, 2019, are described for the first time and the male of I. barkeri is redescribed in greater detail than previously. So far, I. barkeri is known only from a monotreme, the short-beaked echidna, Tachyglossus aculeatus (Shaw, 1792), from the highland rainforests of the Wet Tropics of Far North Queensland, Australia. CONCLUSIONS: Our phylogeny from entire mitochondrial genomes indicated that I. barkeri and indeed I. woyliei Ash et al., 2017, another tick that was described recently, are best placed in the subgenus Endopalpiger Schulze, 1935.

Sheltered life beneath elytra: three new species of Eutarsopolipus (Acari, Heterostigmatina, Podapolipidae) parasitizing Australian ground beetles.

In this study, we conducted a summer sampling of carabid beetles in eastern Australia to identify their associated parasitic mites. Here, we describe three new species of the genus Eutarsopolipus from under the elytra (forewings) of three native carabid species (Coleoptera: Carabidae): Eutarsopolipus paryavae n. sp. (pterostichi group) from Geoscaptus laevissimus Chaudoir; Eutarsopolipus pulcher n. sp. (leytei group) from Gnathaphanus pulcher (Dejean); and Eutarsopolipus chlaenii n. sp. (myzus group) from Chlaenius flaviguttatus Macleay. We further provide an identification key of the world species of pterostichi and leytei species groups as well as closely related species of the myzus group possessing similar characters including short cheliceral stylets. The significant diversity of Eutarsopolipus recovered here suggests that the current knowledge about Australian podapolipid mites (specially Eutarsopolipus) is still in its infancy and deserves further study.

TITLE: Vivre à l'abri sous les élytres : trois nouvelles espèces d'Eutarsopolipus (Acari, Heterostigmatina, Podapolipidae) parasitant des carabes australiens. ABSTRACT: Dans cette étude, nous avons effectué un échantillonnage estival de carabes dans l'est de l'Australie pour identifier leurs acariens parasites associés. Nous décrivons trois nouvelles espèces du genre Eutarsopolipus sous les élytres (ailes antérieures) de trois espèces de carabes indigènes (Coleoptera : Carabidae) : Eutarsopolipus paryavae n. sp. (groupe pterostichi) de Geoscaptus laevissimus Chaudoir, Eutarsopolipus pulcher n. sp. (groupe leytei) de Gnathaphanus pulcher (Dejean) et Eutarsopolipus chlaenii n. sp. (groupe myzus) de Chlaenius flaviguttatus Macleay. Nous fournissons en outre une clé d'identification des espèces mondiales des groupes d'espèces pterostichi et leytei ainsi que des espèces étroitement apparentées du groupe myzus possédant des caractères similaires, y compris des stylets chélicéraux courts. La diversité importante des Eutarsopolipus collectés ici suggère que les connaissances actuelles sur les acariens podapolipidés australiens (en particulier Eutarsopolipus) en sont encore à leurs balbutiements et méritent une étude plus approfondie.

Contrasting species diversification of Eutarsopolipus (Acariformes: Podapolipidae) on Castelnaudia and Notonomus (Coleoptera: Carabidae).

Eutarsopolipus (Acari: Podapolipidae) is a large genus of mites parasitic in the subelytral space of carabid beetles. Herein, I explore the species radiations of Eutarsopolipus on the pterostichine genera Castelnaudia and Notonomus found in the rainforests of eastern Australia. Castelnaudia has an extraordinary radiation of podapolipid mite species, with most beetle species carrying multiple species of mites unique to each host. In contrast, each Notonomus species had just one species of Eutarsopolipus (with the exception of a single male mite of another species), and in four of the five host species examined, the single mite species could not be distinguished from each other. The host beetles and their new mite species are: Castelnaudia cordata with E. hebronae sp. nov., E. osculum sp. nov. and E. umbonatus sp. nov.; Castelnaudia eungella with E. savatus sp. nov.; Castelnaudia marginifera with E. labiatus sp. nov.; Castelnaudia mixta with E. mixtus sp. nov.; Castelnaudia porphyriaca with E. basiatus sp. nov., E. despoticus sp. nov. and E. teuceri sp. nov.; Castelnaudia septemcostata with E. nahmani sp. nov. and E. raveni sp. nov.; Castelnaudia setosiceps with E. hadros sp. nov.; Notonomus aurifer, N. dimorphicus, N. flos and N. spurgeoni with E. janus sp. nov.; and Notonomus transitus with E. biuncatus sp. nov. All the described species from Castelnaudia were from the ochoai species group, and the species on Notonomus were from the leytei species group. Ten additional undescribed species were also found on these hosts, all in numbers insufficient for description: nine from Castelnaudia (ochoai and pterostichi species groups) and one from Notonomus (undetermined species group). Synhospitality was common on Castelnaudia, with four species of Eutarsopolipus on C. cordata, C. eungella, C. porphyriaca and three on C. septemcostata. Co-infestation was also common, with one-third of infested beetles hosting two or more species of Eutarsopolipus. I speculate that the greater longevity and slower speciation rates of Castelnaudia have permitted more successful host-switching and speciation of its parasites.

Discovering and documenting Acari: the first twenty years in Zootaxa.

Acari represent the most diverse group within the arachnids with some 60,000 described species. It is generally believed that most species of mites are waiting to be discovered and described. Zootaxa was the most important journal for mite taxonomy during the last twenty years (2001 to 2020). It published 1305 papers by 1057 authors during these two decades, with descriptions of 3271 new taxa/names, which account for 24.4% of the total indexed in Zoological Record. The numbers of new synonyms of Acari in Zootaxa (334) also accounted for nearly a quarter (24.9%) of the total published during this period. These data indicate that Zootaxa has been an important and leading journal for acarologists to document the diversity of mites and ticks in the world.

Dorsal setae in Raoiella (Acari: Tenuipalpidae): Their functional morphology and implication in fluid secretion.

The setae of mites are not regarded as secretory structures, yet in the flat mite genus Raoiella, each developmental stage presents droplets of fluid associated with the tips of their dorsal setae. To understand the origin of this fluid, the ultrastructure of the dorsal setae is investigated in females of Raoiella bauchani Beard & Ochoa and the invasive pest species Raoiella indica Hirst using scanning and transmission electron microscopy techniques. The dorsal setae are barbed along their entire length and have either a broadened plumose or a flat spatulate tip. Ultrastructurally, they present the typical features of mechanoreceptors, but have a "hollow" axis represented by a protoplasmatic core containing dendritic branches. This combination of ultrastructural characters indicates that the setae might be multimodal receptors: acting as both mechanoreceptors and contact chemoreceptors. The epidermal cells that underlie the setal sockets are columnar and have an ultrastructure that suggests they have a glandular function. Moreover, these cells present regular microvilli apically and form extracellular cuticular canals, containing epicuticular filaments, that are connected with the microvilli proximally and which open via pores onto the surface of the setal base distally. This arrangement indicates that the secretion from the microvilli passes into the canals and is then conducted to pores at the base of the seta, where it then accumulates and moves up the setal shaft, along the longitudinal grooves of the barbs. Based on similar arrangements in some insect taxa, the organization of the structures here observed in Raoiella suggests the passage of a non-polar, water insoluble, lipoid fluid through the cuticle, the function of which is still obscure.

The megisthanid mites (Mesostigmata: Megisthanidae) of Australia.

The Australian Megisthanidae are revised, resulting in the description of five new species from passalid beetles (Coleoptera: Passalidae) in Queensland: M. manonae sp. nov. from Mastachilus australasicus; M. simoneae sp. nov. from Mastachilus polyphyllus; M. southcotti sp. nov. from Aulacocyclus fracticornis; M. womersleyi sp. nov. from Protomocoelus australis; and M. zachariei sp. nov. from Aulacocyclus kaupii. Megisthanus womersleyi is also based on material from Misima Island, Papua New Guinea, originally identified as Megisthanus doreianus Thorell, 1882. Megisthanus modestus Berlese, 1910, is redescribed based on material from Pharochilus spp. collected from Canberra, New South Wales, Queensland and Tasmania. The Papua New Guinean species Mastachilus papuanus Womersley, 1937 is diagnosed and discussed in relation to the other species from New Guinea. Additional collections of Megisthanus leviathanicus Seeman, 2017 and M. thorelli Womersley, 1937 are also reported. A genus description and a key to the eight Australian species of Megisthanus are provided.

Two new species of Australian Eutarsopolipus (Acariformes: Podapolipidae) from Nurus medius (Coleoptera: Carabidae).

Eutarsopolipus burwelli sp. nov. and E. echinatus sp. nov. (Acari: Podapolipidae) are described from Nurus medius Darlington, 1961 (Coleoptera: Carabidae), a large burrowing carabid beetle found in the rainforests of coastal central Queensland, Australia. Eutarsopolipus burwelli belongs to the ochoai species group, which is herein refined, and E. echinatus is placed tentatively in the pterostichi species group. A revised key to the species groups of Eutarsopolipus is provided. The synhospitalic species of Eutarsopolipus are reviewed and synhospitality within the genus is discussed.

New species of Eutarsopolipus (Trombidiformes: Podapolipidae) from the pterostichine genera Castelnaudia and Trichosternus (Coleoptera: Carabidae) in Australia.

Three new species of Eutarsopolipus Berlese are described from the flightless pterostichine carabid genera Castelnaudia Tschitscherine and Trichosternus Chaudoir found in rainforests in eastern Queensland: Eutarsopolipus piraticus sp. nov. from Trichosternus frater Darlington and T. mutatus Darlington in north-east Queensland; E. uncatus sp. nov. from C. obscuripennis (Macleay) in north-east Queensland; and E. verberatus sp. nov. from Castelnaudia eungella (Darlington) in middle-eastern Queensland and C. wilsoni (Castelnau) in south-east Queensland. These species are unique in Eutarsopolipus by having large hook-like unguinal setae on tarsi II-III. All species differ by only a few minor features, and the geographically isolated populations of E. verberatus could not be distinguished reliably. Surprisingly, the presence/absence of leg I claws and seta v″ on femur I, which have been used to create species groups, is intraspecifically variable. Species delimitation and the tarsal setation of Podapolipidae, particularly Eutarsopolipus, are also discussed.

A revision of the Heatherellidae (Parasitiformes: Mesostigmata) with a new genus and two new species from Australasia.

The discovery of a new genus of Heatherellidae in New Zealand has led us to revise this enigmatic family and its constituent genera. Aheatherella n. gen., based on A. mira n. sp. from the North Island of New Zealand, lacks some of the derived character states that link the Australian Heatherella, most notably the lack of sexual dimorphism in the dorsal shields and in the presence of peritremes in adult Aheatherella. Heatherella osleri n. sp. is described from New South Wales, extending the distribution of this genus beyond Queensland. New collection records of H. callimaulos and a key to the genera and species of the family are provided. We propose that the Heatherellidae-previously placed in its own cohort outside the Gamasina-are best considered a superfamily of gamasine mites within the subcohort Epicriiae.

A new tribe of tarsonemid mites (Trombidiformes: Heterostigmatina) parasitic on tetrigid grasshoppers (Orthoptera).

Podotarsonemini tribe nov. (Tarsonemidae: Acarapinae), with one nominate genus Podotarsonemus gen. nov., is proposed for seven new species of tarsonemid mites collected from the hindwings of pygmy grasshoppers of the family Tetrigidae (Orthoptera). The new tribe is placed within the tarsonemid subfamily Acarapinae on the basis of several morphological synapomorphies, as well as on parasitism of insects. In light of this new tribe, a revised description of the Acarapinae is provided, as are full tribal, generic and species descriptions for the Podotarsonemini, and a key to species. In view of Podapolipidae, the sister family of Tarsonemidae, consisting entirely of obligatory parasitic mites, the distinction between the two constituent sister families of Tarsonemoidea as well as the ancestral feeding habits of that superfamily are considered. These mites and their host grasshoppers were collected from Bolivia, Ecuador, Honduras, southern India, Japan, Papua New Guinea, South Africa and two localities in north-eastern Australia. This distribution suggests that the Podotarsonemini are an ancient lineage of Tarsonemidae that radiated on the Gondwanan Tetrigidae during the Jurassic.

Two new species of Tenuipalpus Donnadieu, 1875 (Acari: Trombidiformes: Tenuipalpidae) from Iran.

Two new flat mite species (Acari: Trombidiformes: Tenuipalpidae), Tenuipalpus iranicus sp. nov. ex. Salix aegyptiaca (Salicaceae) and Tenuipalpus kermanicus sp. nov. ex. Tamarix aphylla (Tamaricaceae) from the Hormozgan and Kerman provinces of Iran, respectively, are described and illustrated. These species belong to the proteae species group. Tenuipalpus iranicus sp. nov. is placed in the xerocolus subgroup due to having two pairs each of setae 3a and 4a, and T. kermanicus sp. nov. is placed in the keiensis subgroup because it has one pair of setae 3a and two pairs of 4a.