Pretarsal Claws Research Articles

<i>Andrena nimigracilis,</i> a New Species (Hymenoptera: Andrenidae) from México

Andrena nimigracilis Zabinski, new species, is described from a single male specimen from the state of Michoacán in México. It can be distinguished from males of all other species of North American Andrena by the following combination of characters: metasoma extremely narrow, humeral angle extremely weak, propodeum declivitous, genal area small, compound eye wide compared to its length, pretarsal claws with tooth, vertex ≤1.5x lateral ocellar diameter, and wings hyaline. Due to this unique morphology, this species currently cannot be placed into any Andrena subgenus, therefore placed as subgenus incertae sedis.

Material composition and mechanical properties of the venom-injecting forcipules in centipedes

BackgroundCentipedes are terrestrial and predatory arthropods that possess an evolutionary transformed pair of appendages used for venom injection—the forcipules. Many arthropods incorporate reinforcing elements into the cuticle of their piercing or biting structures to enhance hardness, elasticity or resistance to wear and structural failure. Given their frequent exposure to high mechanical stress, we hypothesise that the cuticle of the centipede forcipule might be mechanically reinforced. With a combination of imaging, analytical techniques and mechanical testing, we explore the centipede forcipule in detail to shed light on its morphology and performance. Additionally, we compare these data to characteristics of the locomotory leg to infer evolutionary processes.ResultsWe examined sclerotization patterns using confocal laser-scanning microscopy based on autofluorescence properties of the cuticle (forcipule and leg) and elemental composition by energy-dispersive X-ray spectroscopy in representative species from all five centipede lineages. These experiments revealed gradually increasing sclerotization towards the forcipular tarsungulum and a stronger sclerotization of joints in taxa with condensed podomeres. Depending on the species, calcium, zinc or chlorine are present with a higher concentration towards the distal tarsungulum. Interestingly, these characteristics are more or less mirrored in the locomotory leg’s pretarsal claw in Epimorpha. To understand how incorporated elements affect mechanical properties, we tested resistance to structural failure, hardness (H) and Young’s modulus (E) in two representative species, one with high zinc and one with high calcium content. Both species, however, exhibit similar properties and no differences in mechanical stress the forcipule can withstand.ConclusionsOur study reveals similarities in the material composition and properties of the forcipules in centipedes. The forcipules transformed from an elongated leg-like appearance into rigid piercing structures. Our data supports their serial homology to the locomotory leg and that the forcipule’s tarsungulum is a fusion of tarsus and pretarsal claw. Calcium or zinc incorporation leads to comparable mechanical properties like in piercing structures of chelicerates and insects, but the elemental incorporation does not increase H and E in centipedes, suggesting that centipedes followed their own pathways in the evolutionary transformation of piercing tools.

Ripidinelia daiboyui sp. nov. from mid-Cretaceous Kachin amber (Coleoptera: Ripiphoridae)

The second species of the ripidiine genus Ripidinelia Batelka & Prokop, R. daiboyui Li & Cai sp. nov., is reported from mid-Cretaceous Kachin amber of northern Myanmar. Ripidinelia daiboyui is distinguishable from R. burmiticola Batelka & Prokop by having 5-5-4 tarsi. The apically dentate pretarsal claws found in R. daiboyui are rarely present in Ripidiinae. Together with previous studies, our discovery emphasizes the palaeodiversity of Ripiphoridae during the late Mesozoic.

New fossils of Sphaeriusidae from mid-Cretaceous Burmese amber revealed by confocal microscopy (Coleoptera: Myxophaga)

Sphaeriusidae is a small family of tiny aquatic beetles in the suborder Myxophaga. In this study we characterize two new sphaeriusid fossils from the mid-Cretaceous Burmese amber with the help of confocal laser scanning microscopy. Sphaerius martini Li & Cai sp. nov. displays similarities with both extant Bezesporum and Sphaerius, although it can be readily recognized based on the parallel-sided prosternum. Crowsonaerius minutus Li & Cai gen. et sp. nov. differs from other genera of Sphaeriusidae in having unreduced apical maxillary palpomeres, lowered mesoventrite, large metacoxal plates, separated mesotrochanter and mesofemur, and equal pretarsal claws. The present study demonstrates the efficacy of confocal microscopy in studying minute and dark bioinclusions in amber.urn:lsid:zoobank.org:pub:6E6EDC20-744A-4A75-849A-4B6126628C15.

Three new genera of Schizogyniidae (Parasitiformes: Mesostigmata) from a New Caledonian millipede (Spirobolida)

Three new monotypic genera of Schizogyniidae, Terrogynium gen. nov., Xenogynium gen. nov. and Zygogynium gen. nov., are described from a spirobolid millipede in New Caledonia. Terrogynium has females with chelicerae presumably modified for parasitism, and both sexes have numerous flattened ventral setae, convergent with many Paramegistidae. Xenogynium and Zygogynium are less-specialised genera with the former appearing closer to Terrogynium. Genus relationships are difficult to determine. These three genera are probably most closely related to each other but as a group it lacks convincing unique synapomorphies. Possible synapomorphies may instead reflect convergence for living on hosts, such as their shortened peritremes and loss of pretarsal claws, characters found elsewhere in the Schizogyniidae. The origins of the Schizogyniidae are discussed and a key to genera of Schizogyniidae is provided.

The first larval record of Migadopinae (Coleoptera: Adephaga: Carabidae) from mid-Cretaceous Kachin amber, northern Myanmar

A new genus and species of Carabidae (Coleoptera: Adephaga), Cretomigadops bidentatus gen. et sp. nov., is described based on a well-preserved specimen from mid-Cretaceous Kachin amber from northern Myanmar. It is a first instar shortly after hatching, with distinct, elongate frontal eggbursters and a disproportionally large head. Cretomigadops bidentatus gen. et sp. nov. displays typical adephagan features and is classified as a larva of Carabidae based on a strongly sinuate frontal suture. It is assigned to Migadopinae based on characters of the head, especially the presence of two acute subapical mandibular teeth. It differs from other known genera of this small subantarctic subfamily by its long urogomphus, elongate legs with equal pretarsal claws and a long abdominal segment X. It is the first definite Mesozoic larval record of Carabidae from amber. Differences between C. bidentatus gen. et sp. nov. and four other fossil caraboid larvae are also discussed. The mandibles with a falcate apical tooth and two additional sharp subapical teeth indicate that C. bidentatus gen. et sp. nov. was a specialized active predator and good at grasping and piercing small arthropods. The elongate and articulated urogomphi, the long legs, the well-developed stemmata and the pigmented cuticle indicate that the larva was a surface runner, moving mostly on the soil surface and hunting more or less fast-moving prey. In contrast to the subantarctic distribution of Migadopinae, C. bidentatus gen. et sp. nov. preserved in Burmite shows that the distribution range of the subfamily was wider in the Mesozoic.

A remarkable finding of Centroptilum Eaton, 1869 (Ephemeroptera: Baetidae) in Georgia, Turkey and Iran: one new species evidenced by morphology and DNA

The genus Centroptilum Eaton, 1869 is widely distributed in the West Palaearctic region, but poorly diversified as it previously only encompassed two valid species, C. luteolum (Müller, 1776) and C. pirinense Ikonomov, 1962. The discovery of a new congener, C. volodymyri Martynov, Godunko and Palatov, sp. nov., is therefore remarkable; the new species is described based on larvae collected in Georgia, Turkey and Iran in 2012–2019. This new species can be distinguished by the structure of the cuticle with flattened, stretched shallow, triangular and semilunar-shaped corrugations; scales and their bases densely scattered on body surface; features of the mouth parts, including the presence of an expanded laterally labrum, in combination with segment III of maxillary palp and superlinguae of hypopharynx rounded apically, without any pointed projections at the tip; numerous small teeth scattered proximally in two rows along inner margin of the pretarsal claw; the shape of denticulation along the posterior margin of the abdominal terga, and the number of prominent posterolateral spines on tergum VII; and the shape of gills II–VII, with a distinctly concave posterior margin. Together with a morphological description, data on the distribution and mitochondrial cytochrome c oxidase subunit I gene (COI) barcode sequences of the species are provided. The species delimitation of C. volodymyri Martynov, Godunko and Palatov, sp. nov. and C. luteolum is tested using COI barcode sequences. The data obtained show that the new species can be distinctly recognised as a separate lineage. The habitat preferences associated with the different parts of the area of C. volodymyri Martynov, Godunko and Palatov, sp. nov. are described and compared. Distribution of C. volodymyri Martynov, Godunko and Palatov, sp. nov. confirms the connections between Caucasian and Asian fauna of Ephemeroptera, as already demonstrated in various families and genera. Short notes on the distribution of mayfly species common to the Caucasus, north-western Iran and Central Asia are presented. http://www.zoobank.org/urn:lsid:zoobank.org:act:1D2B7557-0DEC-4ACD-8CA3-A6B50FCC4A51.

Shedding light on the enigmatic extinct insect order Glosselytrodea: new diversity and key morphological insights into non‐tegmenized Permian forms

AbstractGlosselytrodeans are enigmatic extinct (Permian–Jurassic) insects classified in their own order. The monophyly of Glosselytrodea is not universally accepted and its large‐scale relationships remain problematic, namely because its diversity is largely known from hardened (i.e. tegmenized/‘elytrized’) forewings of allegedly derived forms. Thus, new data on the group’s early diversity and/or complete specimens are critical. Herein we describe the oldest glosselytrodean known,Moscheloptera phantasmagen. et sp. nov. (Permoberothidae), based on a forewing from the Niedermoschel black shale (Germany; early Permian). The holotype ofPermoberotha villosaTillyard (Permoberothidae) (a forewing) and a previously described complete conspecific specimen, both from Elmo (USA; early Permian), are reassessed and photographically figured for the first time. A new, completeP. villosaspecimen from Elmo preserves body structures hitherto not reported among glosselytrodeans, including complex pretarsal claws and detailed male genitalia. The holotypes of two further species,Sylvaelytron latipennatumNovokshonov (herein transferred to Permoberothidae) andArchoglossopterum shoricumMartynova (Archoglossopteridae), are also reassessed and figured. An emended diagnosis and an updated catalogue of the Glosselytrodea are provided.GlossopterumSharov is returned to its own family: Glossopteridae Sharov. Our findings substantially expand the knowledge of the Permoberothidae, which is the earliest glosselytrodean lineage and lacks sclerotization‐related forewing specializations. Although the exact phylogenetic position of glosselytrodeans is still unresolved, the female and male terminalia described herein almost certainly support them as early holometabolan insects, possibly closer to the mecopterid rather than the neuropteroid lineage. Shedding light on Glosselytrodea improves our understanding of the early evolution of the Holometabola.

Review of some mites of the genus Ololaelaps Berlese (Acari, Laelapidae) in Russia, with description of a new species.

This study provides additional morphological information and new illustrations for three species of Ololaelaps Berlese described by Bregetova Koroleva (1964) from RussiaO. caucasicus, O. sellnicki and O. ussuriensisto supplement the original descriptions. Since holotypes for these three species were not designated, a lectotype is chosen from among the syntypes of each examined species. We describe the adult male and female of Ololaelaps altaiensis Joharchi sp. nov., from specimens collected from moss on the shore of the Teletskoye Lake, in Altai Mountains, Russia. The new species is distinguished from other Ololaelaps species by its short peritremes, ending near the middle of coxae II. The new species also has elongate paradactyli, extending well beyond the pretarsal claws; this feature appears to be correlated with the species semiaquatic habitat, and such correlation between tarsal morphology and ecology occurs in other species of Ololaelaps and of Gaeolaelaps with similar habitats.

The first described fossil Oedemeridae (Insecta: Coleoptera) from Baltic amber

AbstractMolecular dating estimates the appearance of the family Oedemeridae in the Early Cretaceous. Several fossil representatives are known from Spanish (105 Ma) and Myanmar (99 Ma) ambers. The family also has been mentioned by several authors to occur in Eocene Baltic amber, but virtually no species was described until now. Here, we provide a description of the first fossil oedemerid species from Eocene Baltic amber, which is classified within subfamily Oedemerinae, in the extant genus Oedemera Olivier as Oedemera (s. str.) girulskii n. sp. The presence of appendiculate pretarsal claws and relatively large eyes separate the new species from its extant congeners.UUID: http://zoobank.org/24b0b919-8684-4908-b002-9521b071dcc8.

The puzzling, rarely encountered European lacewings Chrysoperla ankylopteryformis and C. renoni (Neuroptera: Chrysopidae): one species or two?

ABSTRACT Two of the most intriguing yet poorly understood taxa in the Chrysoperla carnea-group of green lacewings are the European species (alternatively, forms or ecotypes) known as Chrysoperla renoni and C. ankylopteryformis. These two rare taxa have been variously combined and separated by systematists over the years, but their taxonomic status remains controversial, partly because the two have very unusual characteristics, and partly because they are simply difficult to find in nature. Here, we introduce new observations and experimental results, gathered from living individuals collected at new localities in Hungary (C. renoni) and Spain (C. ankylopteryformis). These data encompass duetting song phenotype, mate choice and species recognition, body colour, pretarsal claw dimensions, wing setal length, and predominant habitat associations. The inheritance of several of these traits is also explored, by hybridising each of the two focal taxa with their abundant, co-occurring relative in the carnea-group, C. pallida. Our findings support recognition of C. renoni and C. ankylopteryformis each as valid, independent species, thereby also raising the latter species from its current synonymy with C. renoni (formally, Chrysoperla ankylopteryformis Monserrat & Díaz-Aranda, 1989 stat. rev.). We propose an evolutionary hypothesis to explain the reproductive isolation of these species from one another, as well as from C. pallida. https://www.zoobank.org/urn:lsid:zoobank.org:pub:7800468B-0E79-4634-B523-FDF18BC3EC95

Burrowing specializations in a lacewing larva (Neuroptera: Dilaridae)

Dilaridae are an ancient relict lineage of lacewings, whose life history is poorly known. We investigated the external morphology of the first and second instar larvae of Dilar duelli Aspöck U. and Aspöck H., 1995, based on reared and collected specimens by means of scanning electron microscopy. Larvae of Dilar are characterized by straight mandibulo-maxillary stylets, strengthened antennae and palps, absence of stemmata, robust prothoracic legs with asymmetrical pretarsal claws, greatly elongate and cylindrical abdomen, and large pygopods, all of these features appear to be adaptations to fossorial habits, allowing the larvae to move in the soil. Dilar undergoes drastic developmental changes between larval instars, changing from minute, stout first instars to long, slender third instars, characterized by an overly developed abdomen. Larvae of Dilaridae share several morphological and developmental features with Mantispidae and Berothidae, although phylogenetic evidence suggests that these traits arose independently in association with similar life habits.

Adhesion of Individual Attachment Setae of the Spider Cupiennius salei to Substrates With Different Roughness and Surface Energy

Dynamic adhesion is a key ability for animals to climb smooth surfaces. Spiders evolved, convergent to geckos, a dry adhesive system made of setae branching into smaller microtrichia ending as spatulae. Several previous studies concentrated either on the whole adhesive claw tuft on the spider´s foot that consists of attachment setae or on the single adhesive contact elements, the microtrichia with spatula-shaped tips. Here, the adhesion of single setae of the spider Cupiennius salei was examined and the morphology of the pretarsus and the fine structure of the setae were studied in further detail. Using individual setae fixed to force sensing cantilevers, their adhesion at different contact angles with a glass substrate was measured as well as their adhesive performance on substrates with different roughness and on smooth surfaces with different surface energies. The results show an individual variability of the adhesive forces corresponding to the seta morphology and especially to the seta tip shape. The tip shapes of the setae vary largely even in neighboring setae of the pretarsal claw tuft that comprises approximately 2,400 setae. Regarding surface energy of the substrate, the adhesion force on hydrophobic polytetrafluoroethylene was 30% of that on a hydrophilic glass substrate, which points to the importance of both van der Waals interactions and hydrogen bonds in spider adhesion.

Megabythinus gen. nov., a new stem-group Pselaphinae from mid-Cretaceous Myanmar amber (Coleoptera, Staphylinidae)

Megabythinus spinitibialis gen. et sp. nov. is described from Burmese amber and placed as a stem-group member of the tribe Bythinini. It shares with Boreotethys Parker the second tarsomeres shorter than third tarsomeres, but can be readily separated by the much larger body size, elongate antennomeres, and presence of two asymmetric pretarsal claws.

Living on a sticky trap: natural history and morphology of Bactrodes assassin bugs (Insecta: Hemiptera: Reduviidae: Bactrodinae)

ABSTRACT Plants with glandular trichomes have been shown to attract specialist, mutualistic predatory insects. Despite recent advances in understanding the plant component in this association, few sticky plant specialist insects are well documented and their adaptations to the sticky plant environment are understudied. We here describe and illustrate, for the first time, aspects of the natural history and morphology of a small clade of predatory hemipteran insects, the Bactrodinae (Reduviidae). Our study suggests that these insects are exclusively associated with plant species with glandular trichomes. The relationship is not specific as one species of Bactrodes Stål may be associated with multiple species, genera or even families of plants. We document a unique clamp-like structure formed by one of the pretarsal claws and opposing tarsal spine-like setae that enables Bactrodinae to grasp trichomes and walk on leaves densely covered with trichomes. We further present observations of Bactrodes species scavenging on insects entrapped on leaves. Bactrodinae also oviposit on their host plants, and females engage in behaviours that we interpret as maternal egg guarding, a life history strategy that is rare in predatory true bugs. We speculate that instead of or in addition to decreasing egg predation or egg parasitism, female egg guarding may be a response to the limited availability of sticky plants and a strategy against cannibalism.

Morphology and chaetotaxy of Neotropical Haliplus larvae (Coleoptera: Haliplidae)

Larvae of 2 Neotropical species of Haliplus Latreille, 1802 ( H. indistinctus Zimmermann, 1928 and H. subseriatus Zimmermann, 1921) are described and illustrated including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, and legs. Except for the legs, this is the first treatment of larval primary chaetotaxy for the family Haliplidae. The larvae studied herein have 10 abdominal segments, with segment X forking into 2 caudal projections, 1 pretarsal claw, a clasping device on prothoracic legs, and numerous short tracheal gills on the body, characteristics typically found in haliplid larvae. Regarding primary chaetotaxy, they are characterized by the absence of several setae and pores which are commonly present among other families of Hydradephaga, namely seta FR6 on the frontoclypeus, seta PA16 on the parietal, setae AN2 and AN3 and pore ANg on the antenna, setae MX13 and MX14 on the maxilla, and seta CO6 on the coxa. Mandibular seta MN2 is also strongly developed as compared to other hydradephagans. The larvae of the 2 described species can be separated by comparing the distance from the base of segment X to the point at which it forks into caudal projections.

The endoparasitic larval stages of Eoxenos laboulbenei: An atypical holometabolan development (Strepsiptera, Mengenillidae)

Endoparasitic larval stages of Eoxenos laboulbenei were documented with different techniques, with a main focus on the male tertiary larva. Two discrete endoparasitic stages occur, the secondary and the tertiary larva. The presence of large compound eyes and externally visible wing buds in the tertiary larva is a unique feature within Holometabola. The brain with large optic lobes is followed by a single postcephalic ganglionic complex. The cephalic musculature is greatly reduced but pharyngeal dilators and muscles associated with the mouth field are present. Postcephalic sclerites are absent except for the pronotum. The segmented legs bear filiform pretarsal claws. The indirect flight muscles fill up a large part of the metathorax. The 10-segmented abdomen lacks appendages. Pleural folds are present on the thorax and abdomen. The digestive tract is characterized by a very short oesophagus. The large midgut and the narrow hindgut are disconnected. Six short Malpighian tubules are present. Large testes fill out almost the entire abdomen. In contrast to the tertiary larva, the muscles of the secondary larva are not fully differentiated. Cephalic appendages are present as bud-shaped anlagen. The legs lack a pretarsal claw. The developmental transformations are outlined and discussed, also with respect to phylogenetic implications.

The larval morphology of the spongefly Sisyra nigra (Retzius, 1783) (Neuroptera: Sisyridae).

The morphology of mature larvae of Sisyra nigra was studied and documented with a broad spectrum of techniques. Special emphasis is on the cephalic anatomy and on the digestive tract. Cephalic structures are highly modified, with numerous autapomorphic conditions, including a globular head capsule, an extended area with large cornea lenses, a massive tentorium, a strongly developed prepharyngeal pumping apparatus with a horizontal arrangement of dilators, a sharp bend between the prepharynx and pharynx, and an unusual filter apparatus at the entrance of the large crop. The thoracic and abdominal muscle sets, and the legs are largely unmodified. Postcephalic apomorphies are conspicuous tergal setiferous tubercles, trifid setiferous pleural projections, single pretarsal claws, zigzag-shaped abdominal tracheal gills, and a dense vestiture of setae on the terminal abdominal segments. Mandibulo-maxillary stylets curved outwards are an unusual apomorphy also found in the semiaquatic larvae of Osmylidae. Semiaquatic or aquatic habits and secondarily multisegmented antennae are potential synapomorphies of these two groups and Nevrorthidae (Osmyloidea). A sistergroup relationship between Sisyridae and Nevrorthidae suggests that fully aquatic habits of larvae may be a synapomorphy of both families. A specialized terminal antennal seta is a potential groundplan apomorphy of Neuroptera, with secondary loss in Nevrorthidae and Ithonidae + Myrmeleontiformia, respectively. A trumpet-shaped empodium is likely an apomorphy of Neuroptera excluding Coniopterygidae and Osmyloidea, and the secondary loss an apomorphy of Ithonidae on one hand, and Myrmeleontiformia excl. Psychopsidae on the other.

Waidelotinae, a new subfamily of Pyrochroidae (Coleoptera: Tenebrionoidea) from Baltic amber of the Sambian peninsula and the interpretation of Sambian amber stratigraphy, age and location.

Waidelotus hoffeinsorum gen. et sp. nov. is described from Eocene Baltic amber and assigned to Waidelotinae subfam. nov. within family Pyrochroidae (Coleoptera). The new subfamily differs from the other subfamilies by the following combination of features: penultimate tarsomere of all tarsi deeply bilobed, antepenultimate tarsomere of each pro- and mesothoracic tarsus slightly bilobed, antepenultimate tarsomere of metathoracic tarsi slightly widened apically; pronotum laterally margined in basal half; eyes emarginate; pretarsal claws appendiculate; prosternal intercoxal process incompletely separating prothoracic coxae; pronotum with fine posterior submarginal groove; head without distinct constriction behind eyes; posterior pronotal pits absent; and elytral pubescence homogenous. It is the only authentic species of Pyrochroidae (Coleoptera) from Baltic amber, pending final placement of Palaeopyrochroa crowsoni Abdullah, 1965. Additionally, the available data on stratigraphy of amber-bearing strata on the Sambian peninsula, and the age and location of Eocene amberiferous forests are discussed. A middle Eocene (mostly Bartonian) age is interpreted for the extinct Central European resin-producing forests resulting in the Sambian amber deposits.

Sinopyrophorinae, a new subfamily of Elateridae (Coleoptera, Elateroidea) with the first record of a luminous click beetle in Asia and evidence for multiple origins of bioluminescence in Elateridae.

The new subfamily Sinopyrophorinae within Elateridae is proposed to accommodate a bioluminescent species, Sinopyrophorusschimmeli Bi & Li, gen. et sp. nov., recently discovered in Yunnan, China. This lineage is morphologically distinguished from other click-beetle subfamilies by the strongly protruding frontoclypeal region, which is longitudinally carinate medially, the pretarsal claws without basal setae, the hind wing venation with a well-defined wedge cell, the abdomen with seven (male) or six (female) ventrites, the large luminous organ on the abdominal sternite II, and the male genitalia with median lobe much shorter than parameres, and parameres arcuate, with the inner margin near its apical third dentate. Molecular phylogeny based on the combined 14 mitochondrial and two nuclear genes supports the placement of this taxon far from other luminescent click-beetle groups, which provides additional evidence for the multiple origin of bioluminescence in Elateridae. Illustrations of habitus and main diagnostic features of S.schimmeli Bi & Li, gen. et sp. nov. are provided, as well as the brief description of its luminescent behavior.