Metasomal Segment Research Articles

New pelecinid wasps from mid-Cretaceous Kachin amber, northern Myanmar (Hymenoptera: Pelecinidae)

Five new species in the family of Pelecinidae, Abropelecinus rasnitsyni sp. nov., Abropelecinus rectus sp. nov., Allopelecinus ruoyae sp. nov., Eopelecinus strangulatus sp. nov. and Stelepelecinus minutus sp. nov., are described and illustrated based on seven specimens from mid-Cretaceous Kachin amber. The metasoma of Eopelecinuss strangulatus sp. nov. provides new material to support the first pathway for the evolution of male metasoma as proposed by Guo et al. in 2016. Furthermore, the Stelepelecinus minutus sp. nov. with a long and petiole-like first metasomal segment offers new evidence to support the second proposed pathway for the evolution of male metasoma leading to a long-petiolate metasoma of extant male pelecinid wasps.

A new scolebythid-like chrysidoid genus and species (Hymenoptera: Chrysidoidea) with striking metasomal structure from the mid-Cretaceous Kachin amber

The Cretaceous fossil record of the aculeate superfamily Chrysidoidea has been greatly enriched in the past few years, thanks especially to the abundance of available material in the late Albian-early Cenomanian amber from the Kachin state (Myanmar). We here document the discovery of a new genus and species, Thagyaminobythus martini gen. et sp. nov., from Kachin amber, emphasizing the extraordinary diversity of chrysidoid wasps in this deposit. The genus is left as incertae sedis within the superfamily because it exhibits a combination of Scolebythidae, Bethylidae and Chrysididae features. We discuss the possibility that Thagyaminobythus martini gen. et sp. nov. could retract its posterior metasomal segments and the co-occurrence of such a structure in several chrysidoid families.

Morphological Study of Hemiscorpius Peters, 1861 (Scorpiones: Hemiscorpiidae) in Hormozgan Province, Southern Iran.

Hemiscorpius species are distributed in Africa and Asia. Seven species of this genus have been identified in Iran of which six species have been reported from Hormozgan province. Members of this genus are the most dangerous scorpions in Iran. corpions were collected by moving stones during the day and searching at night using portable UV lights from 2011 to 2022 from different areas in Hormozgan province. Three species were identified from Hormozgan province including Hemiscorpius acanthocercus, H.enischnocela and H. shahii which are endemic to Iran. These species have limited distribution and were reported only from the south of Iran. The number of trichobothria are 3, 10-12 and 15-17 in H. acanthocercus, H. enischnochela and H. shahii, respectively. The measured values showed that H. Shahii is larger than H. enischnochela and H. acanthocercus. Specimens of H. acanthocercus are brown to dark brown samples with dark metasomal segment V. There have been reports of death from biting this species. Members of H. enischnochela are light brown to yellow samples. Members of H. Shahii are large brown samples. All three species have sexual dimorphism. Although these three species can be distinguished based on their morphological characters, the molecular investigation is needed to confirm the validity of all species of this genus. Identifying species and determining their distribution range is very useful in facilitating education and treatment management.

Morphological Study of Hemiscorpius Peters, 1861 (Scorpiones: Hemiscorpiidae) in Hormozgan Province, Southern Iran

Hemiscorpius species are distributed in Africa and Asia. Seven species of this genus have been identified in Iran of which six species have been reported from Hormozgan province. Members of this genus are the most dangerous scorpions in Iran. Scorpions were collected by moving stones during the day and searching at night using portable UV lights from 2011 to 2022 from different areas in Hormozgan province. Three species were identified from Hormozgan province including Hemiscorpius acanthocercus, H.enischnocela and H. shahii which are endemic to Iran. These species have limited distribution and were reported only from the south of Iran. The number of trichobothria are 3, 10-12 and 15-17 in H. acanthocercus, H. enischnochela and H. shahii, respectively. The measured values showed that H. Shahii is larger than H. enischnochela and H. acanthocercus. Specimens of H. acanthocercus are brown to dark brown samples with dark metasomal segment V. There have been reports of death from biting this species. Members of H. enischnochela are light brown to yellow samples. Members of H. Shahii are large brown samples. All three species have sexual dimorphism. Although these three species can be distinguished based on their morphological characters, the molecular investigation is needed to confirm the validity of all species of this genus. Identifying species and determining their distribution range is very useful in facilitating education and treatment management.

A new praeaulacid genus with a new species in Praeaulacidae (Hymenoptera: Evanioidea) from mid-Cretaceous Myanmar amber

A new fossil praeaulacid wasp, Hadraulacus perrarus Li, Shih and Ren gen. et sp. nov., is described and figured from mid-Cretaceous Myanmar amber. The new genus is established based on the following characters: antenna with more than 25 antennomeres; metasoma distinctly longer than mesosoma with the first metasomal segment forming a long petiole; legs long and thin, with tibia spurs 1-1-2, claw with one small subbasal tooth; forewing with 1cu-a postfurcal, 1m-cu shorter than 1-M and 2m-cu, 2r-m absent, 3r-m present, 2 + 3rm nearly trapezoidal, and 1m-cu in contact with 2 + 3rm by a short section of M. In addition, this mid-Cretaceous praeaulacid wasp was preserved together with a cicada nymph, likely the result of an accidental assemblage.

Two new species of burrowing scorpions (Urodacidae: Urodacus) from the Pilbara region of Western Australia with identical external morphology†

Two new species of urodacid scorpion are described from the Pilbara region in Western Australia, where they are both patchily distributed along creek lines in the north-east of the region. Urodacus uncinus sp. nov. and Urodacus lunatus sp. nov. are indistinguishable based on external morphology: adults are medium-sized, yellow burrowing scorpions with remarkable sexual dimorphism in the telson, in which males have a uniquely swollen vesicle and an aculeus that is more strongly curved than other known species of Urodacus. The species are superficially similar to Urodacus similis L.E. Koch, 1977 and Urodacus yaschenkoi Birula, 1903 in the morphology of the first four metasomal segments, which are extremely short and not much longer than high. The two new species can only be discerned from each other based on the morphology of their hemispermatophores, which highlights the extremely conserved morphology of species in the genus and suggests that many new species await description with careful examination of their genitalia.

Филогенетические связи скорпионов рода Mesobuthus (Vaсhon, 1950) из Нижнего Поволжья и Южного Урала

The article presents data on the new location of scorpions of the genus Mesobuthus in the Orenburg Nature Reserve. The aim of the work is to determine the species on the basis of the identified morphological features of populations living in the Southern Urals (the territory of the Orenburg Nature Reserve, Orenburg region, Kuvandyksky Mountains. the district, the vicinity of Aituar village) and phylogenetic relationships with populations living on the territory of the Lower Volga region (Krasnoarmeysky district of the Saratov region, Kamyshinsky district of the Volgograd region, Akhtubinsky district of the Astrakhan region) based on a comparison of nucleotide sequences of COI gene fragments. DNA was isolated from metasomal segments and sequenced using the Sanger reaction. Multiple analysis was performed using the tools of the MEGA X software package. The data obtained by the authors in the course of their work contribute to the development of ideas about phylogenetic relationships between populations of scorpions of the genus Mesobuthus living in the Palearctic in the territories of the Sakhar-Gobi and Scythian steppe regions. In the course of the study, specific morphological features were identified for the Orenburg scorpion population, such as: the number of pectin teeth, the color of the chelicerae of the shell and tergite; the shape of the telson. Thus, the data obtained during the multiple analysis of the decoded DNA sequences confirm the presence of closely related links between the Lower Volga and South Ural scorpion populations. The distinctive features identified during morphological analysis are of interest for further comparative morphological studies in the framework of studying the phylogeny of the genus Mesobuthus.

Andricus protuberans Pujade-Villar & Ferrer-Suay IS A SEXUAL FORM (HYM., CYNIPIDAE, CYNIPINI)

We describe and illustrate the morphological characters of the male of Andricus protuberans Pujade-Villar & Ferrer-Suay, 2015 (Hymenoptera, Cynipidae), an oak gall wasp species considered an asexual generation in the original description. The reasons for this mistake are discussed, and the variability of this species in the metasomal segments is mentioned.

Revealing diagnostic characters through morphological evolution in cleptoparasitic spider wasps (Hymenoptera, Pompilidae, Ceropales)

AbstractSpider wasps (Hymenoptera: Pompilidae) cleptoparasites, such as Ceropales Latreille, have evolved the ability to steal the spiders from other pompilids. This behaviour is often observed with morphological adaptations that might mislead taxonomic decisions due to convergence. For instance, four subgenera, Bifidoceropales Wolf, Ceropales s. str., Hemiceropales Wolf and Priesnerius Móczár and six species‐groups are recognized within Ceropales; all with doubtful identification. We studied species of Ceropales in light of molecular and morphological characters to delimit lineages and to test the applicability of morphological traits in diagnosing them. We used the molecular nuclear markers long‐wavelength rhodopsin and 28S ribosomal RNA, and the mitochondrial Cytochrome C Oxidase I available at Genebank to reconstruct Bayesian and maximum likelihood phylogenetic trees. Our results disagree with the current subgeneric classification. We found that fore wing venation and the shape of the female posterior metasomal segments are key characters to differentiate lineages. We discuss morphological evolution of the sting apparatus using ancestral state reconstructions; and we propose Bifidoceropales as a junior subjective synonym of Ceropales s. str., whereas Priesnerius, stat. resurr. and Hemiceropales are redefined based on male and female morphological traits. This study raises important concerns, from the validity of diagnostic characters currently used to identify cleptoparasite spider wasps—and taxa with habitat constraints leading to homoplasies. Taxonomy can benefit from the reconstruction of ancestral traits by revealing reliable diagnostic characters. Moreover, our investigation provides a framework for evolutionary studies on hymenopteran cleptoparasitoids and sets the basis for future phylogenomic investigations on Ceropales by opening new perspectives for taxonomic acts and guiding taxonomic sampling efforts.

A unique yet technically simple type of joint allows for the high mobility of scorpion tails.

Although being one of the most well-known animal groups, functional and constructional aspects of scorpions and especially of their tail (metasoma) have so far been overlooked. This tail represents a special construction, as it consists of five tube-shaped segments made up of strong cuticle, which are movable against each other and thus manoeuvre the notorious stinger both quickly and very precisely in space. This high mobility of an exoskeletal structure can be attributed to the connection between the segments described here for the first time. This joint allows for the twisting and bending at the same time in a single, simple construction: adjoining metasomal segments each possess an almost circular opening posteriorly, where the next segment is lodged. Anteriorly, these segments possess two saddle-like protrusions laterally, which are able to rotate in two directions on the rim of the posterior circular opening of the previous segment allowing for twisting and bending. The metasomal joint is particularly noteworthy since its mechanism can be compared to that of arthropod appendages. The scorpion metasoma is actually the only known case in Chelicerata, in which an entire body section has been modified to perform tasks similar to that of an appendage while containing digestive organs. The joint mechanism can also inspire technical applications, for instance in robotics.

Comparative morphology of scorpion metasomata: Muscles and cuticle

Scorpions are among the most popular research objects within Arachnida and there is an impressive body of knowledge about their biology, distribution, morphology, etc. Although the poison sting has gained a lot of attention due to its potential lethal effects to humans, hitherto, there has been no comparative morphological study on the metasoma, the body part that delivers the poisonous injection. The metasoma always consists of five body segments terminated by a poison sting, but it presents significant morphological variations, both between sexes and between species. Its form ranges from long and thin to short and rather reduced to thick and dominant. In this study, we investigated species representing major scorpion clades and most of the known morphological disparity. Using high-resolution micro-computer-tomography and 3D-reconstruction, we present the first 3D visualizations of metasomal exo-skeletal elements in combination with their musculature. Despite of morphological varying metasomal forms, in all investigated species, a repeating pattern of muscles was found: four pairs of muscles in metasomal segment one to four and two pairs of muscles in metasomal segment five. However, the metasomal muscles are characterized by an antero-posterior change in their shapes and sizes and interspecific variation was also found in the extrinsic metasomal musculature, i.e. the muscles that link metasoma to mesosoma.

New angarosphecid wasp (Hymenoptera: Apoidea, Angarosphecidae) from the mid-Cretaceous Burmese amber

A new genus and species of the family Angarosphecidae, Decasphex cretacicus gen. et sp. nov., from the mid-Cretaceous Burmese amber is described and illustrated. The new genus and species is most similar to Burmasphex Melo et Rosa, 2018 and can be easily distinguished in having female antenna 10-segmented (vs. 12-segmented), mesosoma more elongate, forewing with cell 2cua lower, and metasomal segments 1–3 not separated with deep constrictions. Ten-segmented female antenna is a novel morphotype example of the morphological diversity of Apoidea. A key to genera of the Angarosphecidae is provided.

A new ichneumonid genus (Hymenoptera: Ichneumonidae: Ctenopelmatinae) from the south of Russian Far East

A new genus and species, Petiolon cephalotes gen. et sp. nov., are described in the tribe Pionini (Ichneumonidae: Ctenopelmatinae) from Primorsky Territory of Russia. The new genus differs from other genera of the tribe by its unusually long, narrow and almost straight first metasomal segment without glymmae, very broad head which is 1.7 times as wide as mesoscutum (measured between tegulae), and unusually thick ovipositor with very thin lower valves in their apical 0.25. The latter character is typical for the Pionini.

Characterization of the fluorescence intensity and color tonality in the exoskeleton of scorpions

Scorpions are a mesodiverse and nocturnal group of arachnids inhabiting most biomes worldwide. Different species of scorpions have divergent adaptations to the substrate they live in, but most of them share an intriguing characteristic: their exoskeleton contains fluorophores that emit blue-greenish fluorescence under ultraviolet radiation. Although there are some reports in the literature on the study of fluorescence in scorpions, the biological functionality of this light emission is currently unknown and is under debate. In this work, the properties of emission from the scorpion's exoskeleton are studied by means of digitally processed photographs taken of living specimens under ultraviolet illumination and complemented with standard spectroscopic measurements of emission and excitation spectra. With the aim of identifying possible correlations between the fluorescence, the characteristics color of the exoskeleton and the biology of the scorpions, 4 families, 9 genera and 24 species were studied. Our results suggest that the intensity of fluorescence is heterogeneous throughout the scorpion's exoskeleton studied here in such a way that pedipalps and metasomal segments fluoresce more intensely than the mesosomal segments. The spectrum of fluorescence across species is practically identical, suggesting that the same fluorophores are present in their exoskeletons. However, the fluorescence intensity emitted by each species varies according to their characteristic color (associated with the exoskeleton optical reflectance). Since the coloration of the exoskeleton is determined by the concentration of melanin and other pigments according to the substrate where scorpions live in, we conclude by suggesting that fluorescence may correlate directly to the ecomorphotype of the scorpions.

The genus Trypoxylon Latreille (Hymenoptera: Crabronidae) in Korea: A revision of the species with flask-shaped metasomal segment 1

Korean Trypoxylon species with flask-shaped metasomal segment 1 is studied. Seven species are recognized, and of which an illustrated key is made. Among them, Trypoxylon imayoshii is new to Korea. Korean materials of Trypoxylon ussuriense and Trypoxylon regium that were groundlessly included in the Korean fauna are also recorded for the first time. For future research, selected characteristics of an unusual form clearly discrete from other known congeners are provided. The form is, however, unnamed herein because the only specimen is seriously decolored.

Revision of the ichneumon-flies of the genus Ischyrocnemis Holmgren, 1858 with resurrection of the genus Terozoa Förster, 1869 stat. resurr. (Hymenoptera: Ichneumonidae)

Genera Ischyrocnemis and Terozoa (both initially monotypic) have been synonymized by H. Townes (1971) and preliminary placed in the subfamily Metopiinae. The results of molecular analyses (Quicke et al. 2009) did not clarify their systematic position. In this work Terozoa Förster, 1869 gen. resurr. (=Parablastus M. Constantineanu, 1973, syn. nov.) is restored from synonyms and placed into the subfamily Tryphoninae. Terozoa includes three species: type of the genus, Terozoa quadridens Perkins, 1962 (= Parablastus bituberculatus M. Constantineanu, 1973, syn. nov.) and two more species described earlier in Parablastus – T. iberica (Kasparyan, 1999) comb. n. and T. anatolica (Gürbüz et Kolarov, 2005) comb. n. The genus Terozoa and species T. quadridens are new records for Russia (North Caucasus, Essentuki). A key to species is provided. Four new Western Palearctic species are in Ischyrocnemis: I. femorator sp. nov. (with two subspecies: Caucasian I.f. femorator subsp. nov. and I. f. turanicus subsp. nov. from Central Asia), I. kotenkoi sp. nov. from the Transcaucasia, I. nigrans sp. nov. from steppes of Eastern Ukraine, Volga region and Kazakhstan, and I. verae sp. nov. from Kopet-Dag. A key to five species of the genus is given. Ischyrocnemis is treated provisionally in Metopiinae after H. Townes (1971), G. Broad and M. Shaw (2005). The characters common for Ischyrocnemis and Metopiinae are discussed: Ischyrocnemis approaches to Metopiinae in having the face and clypeus completely fused and clypeal fovea entirely lacking, that is unusual for most of Ichneumonidae but is typical for many Metopiinae (Acerataspis, Colpotrochia, Periope, Hypsicera, Triclistus, etc.); epipleura very wide (in metopiine present in Colpotrochia, Periope, Hypsicera, Seticornuta, Triclistus, etc.). Unusual for Metopiinae 1st metasomal segment of Ischyrocnemis (without glymmae with spiracles beyond the middle, and strongly narrowed in front of spiracles) found in Periope and in many ways is similar to some other Metopiinae (in genera Apolophus, Colpotrochia).

Unique Metasomal Musculature in Sweat Bees (Hymenoptera: Apoidea: Halictidae) Revealed by Micro-CT Scanning

Bees of the family Halictidae (Apoidea: Anthophila) have three pairs of thick, bundled muscles that are circular to subcircular in cross section within the first metasomal segment, as revealed by micro-CT scanning of 16 species in 15 genera of five bee families. In nonhalictids and the basal halictid subfamily Rophitinae, these muscles are planar (flat and sheetlike), typically lying between the anterior air sacs and abdominal wall. In Nomiinae and Halictinae, these muscles, especially the dorsal-ventral pair, bulge into air-sac space, partly enveloped by air-sac membrane. A possible function may be to facilitate metasomal compression and contraction, and thus air flow. The bundled shape of these derived halictid muscles is similar to that of flight muscles, but further data is needed to determine if they are fibrillar, which would suggest a completely different function.

Sexual dimorphism and reproductive behavior in the Brazilian scorpionTityus pusillus(Scorpiones, Buthidae)

AbstractWe studied sexual dimorphism (SD) and reproductive behavior in the litter‐dwelling scorpion,Tityus pusillus. SD was determined by measuring seven body structure attributes (prosoma, mesosoma, and metasoma lengths, and pedipalp chelae and metasomal segment V lengths and widths) in 634 individuals (211 males and 423 females) from the Arachnological Collection of the Universidade Federal de Pernambuco. Reproductive behavior was observed in 55 couples during nocturnal activity observations conducted in the laboratory. In addition, we evaluated gestation time, hemispermatophore replacement, and sequential courtship. Individuals ofT. pusillusexhibited typical reproductive behavior, with a short courtship time (averaging 10±5 min). Males only accepted new partners at least 48 h after first mating, suggesting that this period may be necessary for hemispermatophore production. Females did not accept new partners for 24–48 h after their first mating. The average gestation period was 85±12 d, ranging 60–100 d. Our results showed a more complex picture of SD than previously described for this species, including features characteristic of both sexual size dimorphism (SSD) and sexual body component dimorphism in scorpions. In general, considering the relatively large size of the prosoma and mesosoma inT. pusillus, it seems reasonable to conclude that female‐biased SSD exists in the species, and that male‐biased sexual body component dimorphism is evident in the metasoma and chelae.

Tersilochinae (Hymenoptera: Ichneumonidae) of Vietnam, Part 2: genus Barychemis Forster, 1869

The genus Barycnemis Forster, 1869 (Hymenoptera: Ichneumonidae: Tersilochinae) is most abundant and species rich in the Holarctic region where about 35 species are known, i.e. 15 species in the Nearctic region and 26 in the Palaearctic region. Beyond the Holarctic region, one species occurs in Central America, two in the Oriental region and one in Australia. Only two species of Barycnemis were recorded from the Oriental region till now: B. dissimilis (Gravenhorst, 1829) from Nepal and B. sanctijohanni (Rao et Kurian, 1951) from North India. Nothing was known about the occurrence of the genus Barycnemis in Vietnam until present day. In this paper, two species of Barycnemis, B. dissimilis and B. liliputana sp. nov., are found to occur in Vietnam. Barycnemis liliputana sp. nov., with body length 1.6 mm and fore wing length 1.4 mm, is the smallest known tersilochine species. The new species may easily be recognized by its extremely small size, very slender antennal flagellum with only 14–16 flagellomeres and highly polished head and mesosoma. It resembles B. gracillima (Thomson, 1889) occurring in Europe, Caucasus and Kazakhstan as both have a similar head and slightly depressed ovipositor, but B. liliputana differs from this species, in addition to the characters listed above, by its slender first metasomal segment with small glymma (similar to those in B. dissimilis and B. tobiasi Khalaim, 2004) and slender legs. Barycnemis dissimilis is also recorded from Taiwan and North India. The genus Barycnemis is recorded from Vietnam and Taiwan for the first time. An identification key to the two Barycnemis species occurring in Vietnam is provided.

The life history of the parthenogenetic scorpion Lychas tricarinatus (Simon, 1884) from Odisha province, India and supplementary notes on Tityus trivittatus Kraepelin, 1898 (Scorpiones, Buthidae)

Observations on the entire life cycle of most scorpion species are scarce. Here, we present precise data of the embryonic and postembryonic development for Lychas tricarinatus with additional notes on Tityus trivittatus. By rearing captive-born Lychas tricarinatus specimen from the Odisha province (India) in isolation until maturation, we could show that virgin females gave birth to offspring proving that specimens are capable of parthenogenetic reproduction. Further, we describe an all-female population of Tityus trivittatus from the Corrientes province (Argentina), which originated from a fully bi-sexual population. In addition we describe the ontogenetic development of these two parthenogenetic, buthid scorpions under laboratory conditions. The Dyar’s constant was evaluated for the carapace, metasomal segment V, and the movable finger of the pedipalp among the instars. The calculated growth factor has a total grand average of 1.26. Lychas tricarinatus females reached maturity after 220days postembryonic development. Moreover, L. tricarinatus females started to reproduce in the 6th or 7th instar and gave birth to an average of 21 neonates after 96days of embryonic development. Tityus trivittatus matured in the 5th or 6th instar and gave birth after 230days to an average of 13 neonates.