Abdominal Spiracles Research Articles

Toxicity of 6-gingerol and Cymbopogon citratus against Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae): Mortality, detoxifying enzymes, and morphological ultrastructure alterations in lice

Pediculus humanus capitis (head louse), which causes pediculosis capitis, remains a global health concern. Plant products are efficient alternative pediculicides for treating the human ectoparasite P. h. capitis which is resistant to permethrin. The study evaluates the toxicity and mechanisms of 6-gingerol and Cymbopogon citratus leaf extract on P. h. capitis. Pediculus humanus capitis adult stages were exposed to three different dosages of 6-gingerol and C. citratus crude leaf extract on filter sheets for 5, 10, and 30 min, respectively. The biochemical approach was used to assess the activity of detoxifying enzymes including acetylcholinesterase (AChE), glutathione S-transferase (GST), and oxidase. Scanning electron microscope (SEM) was used to investigate the ultrastructure of the morphological body of lice. After 30 min, 6-gingerol and C. citratus leaf extract killed P. h. capitis completely. Bioassay periods significantly affected lice mortality (P < 0.05). The LC50 values for 6-gingerol and C. citratus extract were 1.79 μg/cm2 and 25.0 μg/cm2, respectively. 6-Gingerol and C. citratus leaf extract significantly lower AChE and GST activity (P < 0.05). Cymbopogon citratus also caused morphological ultrastructure changes in P. h. capitis, including an irregularly formed head, thorax, abdominal respiratory spiracles, and belly. 6-Gingerol and C. citratus leaf extracts could be used as an alternate pediculicide to decrease P. h. capitis populations.

The transcriptome of Icerya aegyptiaca (Hemiptera: Monophlebidae) and comparison with neococcoids reveal genetic clues of evolution in the scale insects

BackgroundScale insects are worldwide sap-sucking parasites, which can be distinguished into neococcoids and non-neococcoids. Neococcoids are monophyletic with a peculiar reproductive system, paternal genome elimination (PGE). Different with neococcoids, Iceryini, a tribe in non-neococcoids including several damaging pests, has abdominal spiracles, compound eyes in males, relatively abundant wax, unique hermaphrodite system, and specific symbionts. However, the current studies on the gene resources and genomic mechanism of scale insects are mainly limited in the neococcoids, and lacked of comparison in an evolution frame.ResultWe sequenced and de novo assembled a transcriptome of Icerya aegyptiaca (Douglas), a worldwide pest of Iceryini, and used it as representative of non-neococcoids to compare with the genomes or transcriptomes of other six species from different families of neococcoids. We found that the genes under positive selection or negative selection intensification (simplified as “selected genes” below) in I. aegyptiaca included those related to neurogenesis and development, especially eye development. Some genes related to fatty acid biosynthesis were unique in its transcriptome with relatively high expression and not detected in neococcoids. These results may indicate a potential link to the unique structures and abundant wax of I. aegyptiaca compared with neococcoids. Meanwhile, genes related to DNA repair, mitosis, spindle, cytokinesis and oogenesis, were included in the selected genes in I. aegyptiaca, which is possibly associated with cell division and germ cell formation of the hermaphrodite system. Chromatin-related process were enriched from selected genes in neococcoids, along with some mitosis-related genes also detected, which may be related to their unique PGE system. Moreover, in neococcoid species, male-biased genes tend to undergo negative selection relaxation under the PGE system. We also found that the candidate horizontally transferred genes (HTGs) in the scale insects mainly derived from bacteria and fungi. bioD and bioB, the two biotin-synthesizing HTGs were exclusively found in the scale insects and neococcoids, respectively, which possibly show potential demand changes in the symbiotic relationships.ConclusionOur study reports the first I. aegyptiaca transcriptome and provides preliminary insights for the genetic change of structures, reproductive systems and symbiont relationships at an evolutionary aspect. This will provide a basis for further research and control of scale insects.

Revision of Potamobates Champion, 1898 (Hemiptera: Heteroptera: Gerridae) and description of a new genus for P. thomasi Hungerford, 1937.

Potamobates Champion, 1898 (Hemiptera: Heteroptera: Gerridae) heretofore included 18 species distributed from southern Mexico to Peru. They display a distinct morphology, especially regarding the projections of abdominal segment VIII. Specific identification and delimitation are difficult, and the genus lacks a thorough revision and evaluation of inter- and intraspecific variation. Here, we revise Potamobates, redescribe and/or illustrate known species, and describe P. molanoi Floriano and Moreira, sp. nov. and Brailovskybates Floriano and Moreira, gen. nov. The new genus is erected for P. thomasi Hungerford, 1937 and is characterized by the following features: (1) abdomen elongated, longer than the mesothorax; (2) abdominal spiracles positioned at the center of the segments; (3) male abdominal segment VIII without projections; (4) male pygophore and proctiger not rotated in relation to the longitudinal axis of the body; (5) female abdominal tergum VIII subequal in length and width; (6) and posterior margin of female abdominal sternum VII not produced medially, with a pair of lateral projections.

‘Social glands’ in parasitoids? – convergent evolution of metapleural glands in Hymenoptera

AbstractFor over a century, the metapleural gland, an exocrine gland above the hind coxa, has been thought to be a unique structure for ants (Hymenoptera: Formicidae), and regarded as a catalyst for the ecological and evolutionary success of the family. This gland is one of the most researched exocrine glands in arthropods and its anatomy, ultrastructure, and chemistry are well documented. Herein, we describe an exocrine gland from the proctotrupoid wasp Pelecinus polyturator (Hymenoptera: Pelecinidae) with a similar position, structure, and chemistry to the ant metapleural gland: it is located just above the hind coxa, corresponds to an externally concave and fenestrated atrium, is composed of class 3 gland cells, and its extract contains relatively strong acids. We discover that the pelecinid gland is associated with the dilator muscle of the first abdominal spiracle, a trait that is shared with ants, but remained overlooked, possibly due to its small diameter, or obfuscation by the extensive metapleural gland. We also provide a biomechanical argument for passive emptying of the gland in both taxa. Pelecinids and ants with metapleural glands share a close association with soil. The pelecinid metapleural gland might therefore also have an antiseptic function as suggested for ants. We examined 44 other Hymenoptera families and found no glands associated with the oclusor apodeme or any signs of external modification. Our results strongly indicate that this complex trait (anatomical &amp; chemical) evolved independently in ants and pelecinid wasps providing an exceptional system to better understand exocrine gland evolution in Hymenoptera.

Morphological changes in the tracheal system associated with light organs of the firefly Photinus pyralis (Coleoptera: Lampyridae) across life stages.

Oxygen is an important and often limiting reagent of a firefly's bioluminescent chemical reaction. Therefore, the development of the tracheal system and its subsequent modification to support the function of firefly light organs are key to understanding this process. We employ micro-CT scanning, 3D rendering, and confocal microscopy to assess the abdominal tracheal system in Photinus pyralis from the external spiracles to the light organ's internal tracheal brush, a feature named here for the first time. The abdominal spiracles in firefly larvae and pupae are of the biforous type, with a filter apparatus and appear to have an occlusor muscle to restrict airflow. The first abdominal spiracle in the adult firefly is enlarged and bears an occlusor muscle, and abdominal spiracles two through eight are small, with a small atrium and bilobed closing apparatus. Internal tracheal system features, including various branches, trunks, and viscerals, were homologized across life stages. In adults, the sexually dimorphic elaboration and increase in volume associated with tracheal features of luminous segments emphasizes the importance of gas exchange during the bioluminescent process.

Sucking lice and spiracular transpiration: turning a liability into a benefit and a necessity.

Sucking lice feed on blood and therefore ingest more water than they require for maintaining hydration. This water must be excreted; however, unlike other blood-feeding insects, they do not produce urine but do become dehydrated within hours if unable to feed. Using human clothing lice and head lice, Pediculus humanus ssp., and high sensitivity balances, it was shown that recently fed lice lost mass consistently as water ingested with the blood meal was excreted via the respiratory system. If all spiracles were occluded using petroleum jelly, mass/water loss was inhibited. Blocking thoracic spiracles resulted in a slight reduction in the rate of mass loss compared with untreated lice, but blocking the abdominal spiracles resulted in an enhanced rate of mass loss. Lice immersed in water did not lose mass but maintained the same mass for several hours, after which they increased in mass as the tissues became turgid, indicating that the insects were able to block water ingress during the period of stability, but that after some time the mechanism failed allowing water to enter the lice by osmosis.

Head lice dispose of blood meal fluid through breathing tubules

The moment when you realize that your itchy child has an infestation of headlice can be an instant of pure horror suffused with relief. Horror at the thought of the hideous creatures dining on your child's blood, and relief that they can usually be cleared. It's a rite of passage. Most insects that feast on fluids pee large volumes as they process their liquid lunches. But not lice. In fact, they don't urinate at all, for fear of alerting their host to their presence. Yet they lose fluid and dehydrate rapidly if separated from their succulent host, desiccating within 24 h when unable to feed regularly. So how do these pernicious pests dispose of the large volumes of fluid they ingest each day? Headlouse expert Ian Burgess (Insect Research &amp; Development Ltd, UK) decided to find out.Fortunately, Burgess had access to a ready supply of fresh head lice: the school children of Cambridgeshire, UK. ‘Some of our regulars just give us a call when the kids next get lice’, says Burgess, who has been working with local schools and parents for 25 years, helping them to vanquish tenacious infestations. Fortunately, the larger and more robust human clothing louse (Pediculus humanus humanus) survives more easily in the lab, so Burgess was able to keep a colony content by simply offering them a rabbit to feed on once a day.Monitoring the insects’ masses before and after dining, Burgess recorded that the smaller head lice (P. h. capitis ∼0.68 mg) consumed ∼0.11 mg of blood, losing 75% of the mass they gained within 3 h. In contrast, the larger clothing lice (∼1.87 mg) downed more than 50% of their body mass in blood (∼0.98 mg), losing the mass more slowly. ‘Most head lice returned to their pre-feeding mass by approximately 4 h after feeding, compared with 17–24 h for clothing lice’, says Burgess, explaining that head lice dine little and often.However, when Burgess checked how fast the insects lost mass after feeding in air at different humidities, there was no difference in the rate of mass loss, even at 100% humidity. ‘If humidity affected the rate of water loss, then the lice exposed to a saturated atmosphere would have some difficulty eliminating water… through cuticular evaporation’, says Burgess. In other words, the lice must be actively pumping water out of their bodies instead of simply allowing it to evaporate like sweat. But which orifices were the insects losing water from?As insects breathe through a network of tubules (tracheae) that open at structures – spiracles – at the surface of the body, Burgess recorded the mass change of clothing lice as they excreted water after dining and found that the creatures lost 15% of their blood meal mass over the next 40 min. Then, after feeding the lice, he smeared Vaseline (petroleum jelly) over their spiracles and the thoracic spiracles turned out to be particularly critical: blocking them reduced the insects’ water loss by ∼50%. In addition, when Burgess blocked the spiracles by immersing the insects in water – which should allow them to lose water but without breathing air – the lice also failed to lose mass; they could no longer inhale oxygen to power water excretion through their spiracles.Most intriguingly, when Burgess coated the insects’ abdomens in Vaseline, that supercharged their ability to lose water. The partially smothered insects disposed of more than 25% of their blood meal through the remaining spiracles. Burgess suspects that blocking the abdominal spiracles stimulates a feedback mechanism that triggers each louse to work harder to excrete water, ‘with the result that it “overdoes” it’, he says.

Digestive And Tracheal System of Menopon Gallinae (Phthiraptera: Amblycera) Infesting Poultry Bird (Gallus Gallus Domesticus)

The digestive and tracheal system of a poultry shaft louse, Menopon gallinae (Phthiraptera: Amblycera) has been studied in greater details. Alimentary canal of louse was dissected out along with crop under stereozoom binocular microscope. Entire alimentary canal of M. gallinae was found more or less straight and has three basic parts (fore-gut, mid-gut and hind-gut) while crop-teeth was present in the crop. The posterior end of crop contains 20-30 well developed crop-teeth arranged in a single arced plate, in comb-like fashion. Mid-gut was found as simple tube and contributes nearly one half of the total length, while the hind-gut was marked by the opening of Malpighian tubules in alimentary canal. The heart of M. gallinae is of simplest kind, one chambered bulbous structure having three pairs of laterally placed ostia and supported by four pairs of alary muscles. In the tracheal system there were seven pairs of spiracles occurred on the terga of M. gallinae. The first pair of spiracle was found located close to legs while remaining six abdominal spiracles occur from segment 3rd to 8th. The degree of tracheation of various visceral organs has also been noted.

Mimicry in Cretaceous Bugs.

SummaryMimicry is ubiquitous in nature, yet understanding its origin and evolution is complicated by the scarcity of exceptional fossils that enable behavioral inferences about extinct animals. Here we report bizarre true bugs (Hemiptera) that closely resemble beetles (Coleoptera) from mid-Cretaceous amber. The unusual fossil bugs are described as Bersta vampirica gen. et sp. nov. and Bersta coleopteromorpha gen. et sp. nov. and are placed into a new family, Berstidae fam. nov. The specialized mouthparts of berstids indicate that they were predaceous on small arthropods. Their striking beetle-like appearance implies that they were either involved in defensive mimicry or mimicked beetles to attack unsuspecting prey. The latter would represent the first case of aggressive mimicry in the invertebrate fossil record. These findings enrich our understanding of the paleoecological associations and extinct behavioral strategies of Mesozoic insects.

Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels.

The immature stages of ten Mecinus species are described for the first time and those of two other species are redescribed, adding important chaetotaxy characters that were missing from previous descriptions. These species belong to six of the nine assemblages of Mecinus species previously established according to a phylogenetic analysis. All these groupings are confirmed on the basis of several characters of mature larvae and pupae. Moreover, all the species show several characters that are useful for distinguishing them from each other, including cryptic species that previously had few differential characters. Some characters that may be useful for separating Mecinus from other genera in the tribe are suggested. To confirm the taxonomic identification of some larvae, the mtCOII gene was obtained and compared with sequences from identified adult specimens. The most important characters for separating the immature stages of the genera and species groups in Mecinus are the number of palpomeres of the labial palpi (1 or 2), the number of air tubes of the thoracic and abdominal spiracles (unicameral or bicameral), and the number of epipharyngeal setae. The species studied herein were compared with those known from other genera in the tribe Mecinini. Two keys, one to the described larvae and the other to the pupae, are provided. Detailed biological data, several of which are new, on some species are reported.

The Tadpoles of Two Atelopus Species (Anura: Bufonidae) from the Sierra Nevada de Santa Marta, Colombia, with Notes on their Ecology and Comments on the Morphology of Atelopus Larvae

We describe for the first time the tadpole of two endemic harlequin frogs of the Sierra Nevada de Santa Marta, north of Colombia: Atelopus nahumae and A. laetissimus. In addition, we provide further morphological data for a third species, A. carrikeri. We also discuss some external morphological features for the tadpoles of these species and compare them with data currently available in the literature for the genus and with other larvae deposited in the amphibian collection of the Instituto de Ciencias Naturales of the National University of Colombia. The examined characters comprise eight morphometric variables and many traits of external morphology related with the oral apparatus, abdominal disc, fins, and dorsal color pattern. The tadpoles of A. nahumae and A. laetissimus are gastromyzophorous and morphologically similar, sharing a great number of features with their congeners. The tadpoles of A. nahumae, A. laetissimus, and A. carrikeri contrast morphometrically; total length and tail width are the morphometric traits that are useful to differentiate among them. They are also differentiated by the size of the abdominal sucker and spiracle. In A. carrikeri, the abdominal sucker is large relative to that of A. nahumae and A. laetissimus; the spiracle of A. laetissimus and A. carrikeri is not visible in ventral and dorsal view, whereas it is large and conspicuous in A. nahumae. The tadpoles of the species from Sierra Nevada de Santa Marta differ from most of their congeners found in the Cordillera Oriental and Central of Colombia by lacking a dark band on the fins and caudal musculature. We recorded abiotic factors of the microhabitat where tadpoles of A. nahumae were observed (temperature, dissolved oxygen, and water depth). Our results indicate that the probability of finding A. nahumae tadpoles depends on the depth of the stream.

Potential phylogenetic significance of the number of functional abdominal spiracles in beetle pupae, with focus on Staphylinoidea (Coleoptera)

The distribution of functional abdominal spiracles in pupae of Coleoptera is reviewed based on published descriptions and original observations. Aquatic Coleoptera typically have strong modifications, generally including dramatic reductions in the number of functional spiracles and often their modification into either spiracular gills or snorkels, as a response to their environment. But pupae of the great majority of Coleoptera, which are terrestrial, show broad stability across higher taxa. Most terrestrial beetles have at least the first five pairs of abdominal spiracles functional, up to and including a full set of eight pairs. However, the number is unexpectedly low in Scarabaeoidea and within Staphyliniformia, where Histeridae and all Staphylinoidea have a confirmed maximum of four pairs of spiracles. The relation between pupal size and number of functional spiracles in terrestrial pupae is explored, and it is suggested that those groups with an unexpectedly small number of functional spiracles may have passed through a “small-size bottleneck” in their ancestry. However, this hypothesis does not explain why several families of very small beetles in other groups of Coleoptera do not show a similar reduction, and little evidence was found to support a strong relation between pupal size and number of functional spiracles at lower taxonomic levels (below family). Whether pupae are exarate or obtect apparently also has little correlation with the number of functional spiracles. However, the consistency and stability of spiracular reductions in the above groups suggests that deep historical factors are involved and thus the reductions may be of phylogenetic significance. It is urged that establishing the number of functional spiracles in beetle pupae become as standard a feature of pupal descriptions as chaetotaxy and whether they are exarate or obtect.

The tracheal system in post-embryonic development of holometabolous insects: a case study using the mealworm beetle.

The tracheal (respiratory) system is regarded as one of the key elements which enabled insects to conquer terrestrial habitats and, as a result, achieve extreme species diversity. Despite this fact, anatomical data concerning this biological system is relatively scarce, especially in an ontogenetic context. The purpose of this study is to provide novel and reliable information on the post-embryonic development of the tracheal system of holometabolous insects using micro-computed tomography methods. Data concerning the structure of the respiratory system acquired from different developmental stages (larvae, pupae and adults) of a single insect species (Tenebrio molitor) are co-analysed in detail. Anatomy of the tracheal system is presented. Sample sizes used (29 individuals) enabled statistical analysis of the results obtained. The following aspects have been investigated (among others): the spiracle arrangement, the number of tracheal ramifications originating from particular spiracles, the diameter of longitudinal trunks, tracheal system volumes, tracheae diameter distribution and fractal dimension analysis. Based on the data acquired, the modularity of the tracheal system is postulated. Using anatomical and functional factors, the following respiratory module types have been distinguished: cephalo-prothoracic, metathoracic and abdominal. These modules can be unambiguously identified in all of the studied developmental stages. A cephalo-prothoracic module aerates organs located in the head capsule, prothorax and additionally prolegs. It is characterised by relatively thick longitudinal trunks and originates in the first thoracic spiracle pair. Thoracic modules support the flight muscles, wings, elytra, meso- and metalegs. The unique feature of this module is the presence of additional longitudinal connections between the neighbouring spiracles. These modules are concentrated around the second prothoracic and the first abdominal spiracle pairs. An abdominal module is characterised by relatively thin ventral longitudinal trunks. Its main role is to support systems located in the abdomen; however, its long visceral tracheae aerate organs situated medially from the flight muscles. Analysis of changes of the tracheal system volume enabled the calculation of growth scaling among body tissues and the volume of the tracheal system. The data presented show that the development of the body volume and tracheal system is not linear in holometabola due to the occurrence of the pupal stage causing a decrease in body volume in the imago and at the same time influencing high growth rates of the tracheal system during metamorphosis, exceeding that ones observed for hemimetabola.

Intricate but tight coupling of spiracular activity and abdominal ventilation during locust discontinuous gas exchange cycles.

Discontinuous gas exchange (DGE) is the best studied among insect gas exchange patterns. DGE cycles comprise three phases, which are defined by their spiracular state: closed, flutter and open. However, spiracle status has rarely been monitored directly; rather, it is often assumed based on CO2 emission traces. In this study, we directly recorded electromyogram (EMG) signals from the closer muscle of the second thoracic spiracle and from abdominal ventilation muscles in a fully intact locust during DGE. Muscular activity was monitored simultaneously with CO2 emission, under normoxia and under various experimental oxic conditions. Our findings indicate that locust DGE does not correspond well with the commonly described three-phase cycle. We describe unique DGE-related ventilation motor patterns, coupled to spiracular activity. During the open phase, when CO2 emission rate is highest, the thoracic spiracles do not remain open; rather, they open and close rapidly. This fast spiracle activity coincides with in-phase abdominal ventilation, while alternating with the abdominal spiracle and thus facilitating a unidirectional air flow along the main trachea. A change in the frequency of rhythmic ventilation during the open phase suggests modulation by intra-tracheal CO2 levels. A second, slow ventilatory movement pattern probably serves to facilitate gas diffusion during spiracle closure. Two flutter-like patterns are described in association with the different types of ventilatory activity. We offer a modified mechanistic model for DGE in actively ventilating insects, incorporating ventilatory behavior and changes in spiracle state.

The transition from water to air in aeshnid dragonflies is associated with a change in ventilatory responses to hypoxia and hypercapnia

Dragonflies are amphibiotic, spending most of their lives as aquatic nymphs before metamorphosing into terrestrial, winged imagoes. Both the nymph and the adult use rhythmic abdominal pumping movements to ventilate their gas exchange systems: the nymph tidally ventilates its rectal gill with water, while the imago pumps air into its tracheal system through its abdominal spiracles. The transition from water to air is known to be associated with changes in both respiratory chemosensitivity and ventilatory control in vertebrates and crustaceans, but the changes experienced by amphibiotic insects have been poorly explored. In this study, dragonfly nymphs (Anax junius) and imagoes (Anax junius and Aeshna multicolor) were exposed to hypoxia and hypercapnia while their abdominal ventilation frequency and amplitude was recorded. Water-breathing nymphs showed a significant increase in abdominal pumping frequency when breathing hypoxic water (<10 kPa O2), but no strong response to CO2, even in severe hypercapnia (up to 10 kPa CO2). In contrast, both species of air-breathing imago increased their abdominal pumping amplitude when exposed to either hypoxia or hypercapnia, but did not show any significant increase in frequency. These results demonstrate that aquatic dragonfly nymphs possess a respiratory sensitivity that is more like other water breathing animals, being sensitive to hypoxia but not hypercapnia, while their air-breathing adult form responds to both respiratory challenges, like other terrestrial insects. Shifting from ventilating a rectal gill with water to ventilating a tracheal system with air is also associated with a change in how abdominal ventilation is controlled; nymphs regulate gas exchange by varying frequency while imagoes respond by varying amplitude.

Contribution to the cytogenetics of Kuwaniini scale insects (Homoptera, Coccinea, Margarodidae s.l.).

Jansenus burgeri Foldi, 1997 (Margarodidae s.l., Xylococcinae, Kuwaniini) was studied cytogenetically for the first time. It was shown that the species reproduces bisexually, displays XX/X(0) sex chromosome system and 2n=6/5 (female/male) including two pairs of long autosomes and a pair of shorter X-chromosomes in female. The chromosome complement, adult female morphology and the life cycle of J. burgeri are illustrated. The cytogenetic data are in fact the first ones for Kuwaniini scale insects, because Kuwania oligostigma De Lotto, 1959 briefly cytogenetically studied by Hughes-Schrader (1963), in my opinion, may be excluded from the genus Kuwania Cockerell, 1903 and the tribe Kuwaniini, since this species shows aberrant morphological characters, specifically the total absence of abdominal spiracles and the presence of tubular ducts.

On Wet Rocks with Snorkels: Immature Stages ofTritonusCascade Beetles with Unusual Modification of Spiracles (Coleoptera: Hydrophilidae: Laccobiini)

The egg case and larvae of all three instars of the cascade beetle Tritonus complanatus Short, 2008 (Coleoptera: Hydrophilidae) are described based on specimens found co-occurring with adults and associated with them by comparing histone 3 nDNA sequences. The morphology of the larva is congruent with the phylogenetic position of Tritonus Mulsant, 1844 in the Paracymus-group of the Laccobiini, but also exhibits characters shared with larvae of Hydrobiusini, and some presumed adaptations to the hygropetric life style. The larva has open mesothoracic and abdominal spiracles situated on top of long spiracular tubes in the first instar, likely working as ‘spiracular snorkels’, and on low tubercles in later instars, along with a well-developed spiracular atrium. Similar spiracular morphology was found in the larva of the terrestrial laccobiine genus Tormus Sharp, 1884, and a brief examination of larvae of few other genera (Oocyclus Sharp, 1882, Hydrobius Leach, 1815) reveals that the peripneustic spiracular system (mesothoracic plus 8 abdominal functioning spiracles) may be more widespread in larval Hydrophilidae than currently believed.

Tracheal system and biology of the Early Cretaceous Saurophthirus longipes Ponomarenko, 1976 (Insecta, ?Aphaniptera, Saurophthiroidea stat. nov.)

The tracheal system of Saurophthiridae is described based on female fossils of Saurophthirus longipes Ponomarenko, 1976. Three very wide tracheal trunks are found running dorsolaterally along each side of the body. The tracheal system is amphipneustic, with the large mesothoracic and very large 8th abdominal spiracles. The 9th and following segments are able to turn back to open posterior spiracles for breathing. Taken together, these features are characteristic of air breathing aquatic insects. This urges us to modify the former hypothesis about parasitism of Saurophthirus on pterosaur wing membrane. We suppose that Saurophthirus females had gonotrophic cycles: they imbibed blood enough for maturation of a large egg batch, then retreated to a water body as a safe place for digesting and egg maturation, and after oviposition climbed onto emergent plants and waited for pterosaurs patrolling over the water and looking for fish, to start a new cycle. The families Saurophthiridae, Pseudopulicidae, and Tarwiniidae are united in the superfamily Saurophthiroidea Ponomarenko, 1986, stat. nov.

Two new glaphyrids (Coleoptera, Scarabaeoidea) from the Jehol Biota, China

Two new species, Cretohypna puncta sp. nov. and Cretohypna robusta sp. nov., of Glaphyridae are described and illustrated. These fossils were collected from the Jehol Biota, Lower Cretaceous Yixian Formation of Liutiaogou Village in Ningcheng, Inner Mongolia, China. Up to date, 18 fossil species in 6 genera of Glaphyridae have been reported, among which ten species are from China. Respective keys to the Mesozoic genera of Glaphyridae and to species of Cretohypna Yan, Nikolajev & Ren, 2012 are provided. This is the first report of spiracles in fossil Glaphyridae leading to a hypothesis that the character of the 7th abdominal spiracles present in pleural membrane is a plesiomorphy for Glaphyridae.

New Carboniferous fossils of Spilapteridae enlighten postembryonic wing development in Palaeodictyoptera

AbstractA new palaeodictyopterid nymph Bizarrea obscura gen.n. et sp.n. (Spilapteridae) and a new adult specimen of Homaloneura cf. dabasinskasi Carpenter are described from the Pennsylvanian (Moscovian) ironstone nodules of Mazon Creek (IL, U.S.A.). Both taxa share enlarged prothoracic lobes (interpreted by some as winglets), heteronomous meso‐ and metathoracic wing pads or wings, a slender abdomen with pointed laterotergites, and a unique division of the abdominal segments by two transverse sulci. An alternative hypothesis for the placement of Bizarrea within Homoiopteridae is considered on the basis of its large body size and relatively short wing pads. Based on the morphology of the new material, postembryonic development of wing pads in Palaeodictyoptera (Palaeodictyopterida) is reconsidered. Detailed investigation of the abdominal segments, including examination by scanning electron microscopy, reveals the presence of subcircular, sclerotized structures partially covered at the bases of the nymphal laterotergites I–VII, ?VIII. Based on their position and shape, these structures are interpreted as abdominal spiracles, and thus a terrestrial or semiaquatic habitat for these immatures is hypothesized. Moreover, our discovery of the same, supposedly homologous structures in the enigmatic Vogesonymphidae (Permoplectoptera), from the Middle Triassic of Grès à Voltzia in France, is evidence for the parallel coexistence of ancestrally terrestrial and derived aquatic lineages of Ephemerida (Ephemeropterida) in early Mesozoic ecosystems.This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:A7270D99‐5B48‐4EAC‐AEB8‐EFB8A9F55FBD.