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 with regard to 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 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.

Redescription, molecular features, and neotype deposition of Rhipicephalus pusillus Gil Collado and Ixodes ventalloi Gil Collado (Acari, Ixodidae)

Two species of ticks, Rhipicephalus pusillus Gil-Collado and Ixodes ventalloi Gil-Collado are redescribed, their molecular features (16S rDNA) compared with near species, and neotypes named and deposited. The male of R. pusillus is characterized by a smooth dorsal surface, with relatively short marginal grooves, not reaching the eyes and reaching the first festoon, longer than wide adanal plates, internally concave and widely rounded posteriorly, without internal spurs, accessory adanal plates not projecting over the cuticle, and a narrow, long and straight process on the spiracular plate. The female has very small porose areas, separated by 2.5-3 diameters, and a large triangular spur on the ventro-internal side of the palpal article 1. The nymph has lateral processes curved anteriorly in the ventral aspect of the basis capituli, long auriculae, and internal spurs on the four coxae. The larva of R. pusillus is separated by the presence of spurs on the ventral surface of palpal segment I, together with the rounded apices of the palpi. Features of 16S rDNA cluster this species near the R. sanguineus s.l. complex of species. The distinctive feature of the female of I. ventalloi is the long and curved auriculae, which are absent in every other species of Ixodes reported in the Western Palaearctic. The male is characterized by relatively long conscutal setae and deep and well defined cervical fields. The nymph is unique by having slightly apparent lateral carinae and small cornua, very abundant and long alloscutal setae, about six times longer than those on the scutum and internal spur of coxa I reaching coxa II. The larva of I. ventalloi has Md1-Md3 setae of the same size as the rest of the conscutal setae, which are only slightly longer than the scutal setae, cornua present, and anal groove clearly divergent. In addition to the unique combination of morphological features, the molecular 16rDNA sequence clearly separates I. ventalloi from other species of the I. ricinus group. We named and deposited in an internationally accessible collection the neotypes of both species, since the holotypes were lost.

Anomalies in Hyalomma marginatum larvae (Acari: Ixodidae) in relation to taxonomic studies

Morphological anomalies are most frequently noted in adult ticks. Therefore, in this paper, we describe interesting morphological anomalies in Hyalomma marginatum larvae from a laboratory-reared colony of Syrian specimens. Specimens with abnormalities were found among many thousands of larvae and analysed using scanning electron microscopy. Additionally, we analysed changes in the morphological traits (length and width of tarsi I and III; length and width of coxae I, II, and III) in abnormal specimens of H. marginatum larvae. Teratological changes were noted in the larval gnathosoma (reduction or elongation of chelicerae and change in the location of chelicerae on the basis capituli; abnormal shape and size of the palpal segment) and legs (fusion of four segments of adjacent legs and deformations of leg segments). The investigations have shown low variability of the morphometric traits of tarsi I and III as well as coxae I, II, and III in the H. marginatum larvae from the Syrian population, which can be used in the diagnostics of this species. Knowledge of different types of anomalies in tick larvae can prevent mistakes in identification of abnormal specimens collected in natural conditions.

Neuronal projections from the Haller's organ and palp sensilla to the synganglion of Amblyomma americanum§

The present study was conducted to elucidate the neuronal pathways between peripheral olfactory and taste sensilla and the synganglion in an Ixodidae tick species. The tarsus of the front legs (olfactory nerves) and the fourth palpal segment (gustatory nerves) of unfed Amblyomma americanum males and females were excised. A neuronal tracer, dextran tetramethylrhodamine, was used for filling of the sensory neurons. The synganglion preparations were examined using a confocal microscope. Neuronal arborizations from the Haller’s organ were confined to the olfactory lobes and the first pedal ganglion. The estimated number of olfactory glomeruli ranged from 16 to 22 per olfactory lobe in the females. The number of glomeruli was not counted in males because they were densely packed. Sensory neurons associated with sensilla at the distal end of the palpal organ projected into the palpal ganglion in the synganglion through the palpal nerve. Gustatory sensory neurons associated with palpal sensilla projected into a commissure with several bulges, which are confined in the palpal ganglion. The findings of distinct projection patterns of sensory neurons associated with the Haller’s organ and palpal organ in the lone star tick from this study advanced our knowledge on mechanisms of sensory information processing in ticks.

Antennal and palpal sensilla of Forcipomyia (Lasiohelea Kieffer) fairfaxensis Wirth, 1951 (Diptera: Ceratopogonidae) from Algonquin Park, Ontario

The antennal and palpal sensilla of Forcipomyia (Lasiohelea) fairfaxensis, a biting midge that bloodfeeds on frogs in Algonquin Park, Ontario, were examined by light and electron microscopy and compared with those of Culicoides species. A cluster of ~26 bulbous sensilla occurred in a pit on the third palpal segment (an intermediate number of sensilla compared with the mammalophilic and ornithophilic species). Four types of sensilla (chaetica, trichodea, basiconica, and coeloconica) found on the antennae differed in their distribution from, and were significantly higher in number than on either mammalophilic or ornithophilic ceratopogonids.

A pictorial field guide for the rapid identification of sandflies (DIPTERA: PSYCHODIDAE), commonly encountered in Pará state, Brazil.

A pictorial field guide to the 30 species of sandfly most commonly encountered in Pará State is presented, based on the easily recognised external characters of the length of the 5th palpal segment, thoracic infuscation, abdominal colour and head and body size. In most cases this allows identification to the species. In others, especially with females, it gives an indication of the species, which may then be confirmed with data from more detailed taxanomix studies. This type of field guide helps in teaching, rapid sorting of flies prior to dissection and in acquainting visitors with the variety of species present in a given area.A rapid technique for the taxonomic sorting of unmounted, freshly killed female sandflies is required, prior to the dissection of large numbers of a particular species. Such a method is useful in areas where numerous species occur in studies on natural flagellate infections, age determination and for ecological studies. With the above points in mind a pictorial field guide has been designed that enables the identification of unmounted, unmacerated specimens of the 30 more commonly encountered species of phleboto-mine sandflies (***) in Pará State, North Brazil. It is based on the easily recognised external characters of the length of the 5th palpal segment, thoracic infuscation, ad-dominal colour and proboscis and body size.Taxonomy of male phlebotomine sandflies is based on the structure of the genitalia and, as most of this is external, a wholly external character key is readily made. Female taxonomy, however, is based on the internal character of the cibarium, pharynx and sperma thecae. In order to produce an external character key we therefore return to an unso phisticated "phlebotometry" (see Martins et al., 1978 p. 3 for review), using relative lengths of the proboscis, palpal segments and body, along with the degree of infuscation. Ihis idea is not new; indeed many sandfly specialists presently use external characters to separate certain species (H. Fraiha, R. P. Lane, P. D. Ready, D. G. Young and R. D. Ward personal communications 1983 & 1984).A key used to separate five anthropophillic sandflies by Biagi (1966), in Mexico, was based mainly on palpal segment length and infuscation. Floch and Abonnenc (1952) stressed the use of relative lengths of palpal segments in their keys to the sandflies of French Guiana, and four members of the shannoni group have been similarly separated according to the degree of infuscation by Morales et al. (1982). The use of thoracic infuscation as a reliable character seems to be gaining favour, having been used by young & Fairchild (1974) and Ready & Fraiha (1981). Indeed Chariotis 1974) showed the usefulness of thoracic infuscation to sepenate 7 anthropophillic species, during studies onvesicular stomatitis in Panama. Identification using external characters is essential for work on viral isolations from sandflies, where bulk samples of whole sandflies are used.Perhaps the major advantage of a simple visual guide is for teaching purposes. Technical staff in this lnstitute are able to identify most of the species they encounter without having to use the standard, more unwieldly (and in many cases unavailable) internal character keys, and the guides presented below have allowed rapid species sorting prior to the dissection of sandflies in our leismaniasis study areas (Ryan et at. ,1985).

Descriptions of the larvae of four species of Procladius from Great Slave Lake (Chironomidae:Diptera)

Descriptions of larvae of Procladius denticulatus, Procladius culiciformis, Procladius freemani, and Procladius bellus collected from Yellowknife Bay (lat., 62°25′; long., 114°20′) are given. Procladius denticulatus was separated from the other species by its large size, a character which always proved distinctive. Procladius culiciformis and P. freemani were separated from one another through several measurements including those of the basal antennal segment and the basal palpal segment. Almost all characters of the head were useful in distinguishing the much smaller P. bellus from the other species.

Studies on the sense organs on the palps of selected culicine mosquitoes

Four structures are found on the maxillary palps of female culicine mosquitoes: microtrichia, scales, sensilla chaetica, and thin-walled, bulb-shaped organs. The bulb organs are localized on the distal half of the ventral part of palpal segment 4, have perforated walls, are carbon dioxide receptors (Kellogg, in press), and vary in number among the species from 29/palp on Aedes aegypti to 89/palp on Culex restuans. An explanation for observed behavioral responses to carbon dioxide is given.

A SYNOPSIS OF HOLCOPSIS (DIPTERA: TABANIDAE)

Four species are recognized in the genus Holcopsis Enderlein: bifenestrata (Osten Sacken 1886), fenestrata Enderlein 1923, bequaerti (Philip 1943) and pilifera (Philip 1943). All specimens for which the locality is known are from the State of Durango, Mexico. The genus is characterized and its possible relationship with Bolbodimyia Bigot is indicated. Collection data for all known specimens are given. The species are characterized by the use of a descriptive key. The wing, third antennal segment, and second palpal segment of the female of each species is illustrated.