The tentorium and anterior head sulci in Dictyoptera and Mantophasmatodea (Insecta)

The tentorium, the anterior sulci of the head capsule (epistomal, subgenal, subantennal, circumantennal, and circumocular sulci), and the extension of the anterior tentorial pit were studied in 26 species of Blattaria (representing most principal lineages), 4 species of Mantodea (including the basal Mantoida schraderi), and 1 species each of Isoptera (the basal Mastotermes darwiniensis) and Mantophasmatodea (Austrophasma caledonense). The morphology of these head structures is compared with literature data on other insect orders, mainly Phasmatodea, Orthoptera, Dermaptera, Embioptera, and Plecoptera, and partly Odonata and Zygentoma. Characters are defined, presented in a matrix, and evaluated with regard to phylogenetic implications and homoplastic evolution. The structural relationships of the subantennal sulcus to the subgenal, circumocular, and circumantennal sulci, which are highly variable and strongly homoplastic (depending much on the size of the compound eyes) are a focal issue; several types of subantennal sulci are defined. The presence of an anterior transverse bridge in the tentorium (“perforated tentorium”) of all Dictyoptera here studied confirms the monophyly of this group. Mantophasmatodea lacks this element.     

Head anatomy of adult Coniopteryx pygmaea : Effects of miniaturization and the systematic position of Coniopterygidae (Insecta: Neuroptera)

External and internal head structures of adult Coniopteryx pygmaea Enderlein, 1906, one of the smallest known lacewings, are described in detail for the first time. Possible effects of miniaturization and two hypotheses on the phylogenetic position of Coniopterygidae are evaluated and compared with data from literature. Several convergent modifications in C. pygmaea and other miniaturized insect species are outlined, e.g., a relative increase in the size of the brain, simplification of the tracheal system with respect to the number of tracheae, and reduction of the number of ommatidia and diameter of the facets. Further, the ocular ridge is bell-shaped and countersunk into the head capsule. The cuticle is weakly sclerotized and equipped with wax glands which are unique in Neuroptera. The total number of muscles is not affected by miniaturization. The phylogenetic analysis yields Coniopterygidae as sistergroup to the dilarid clade based on one larval character, the shape of the stylets. The enforced basal position of Coniopterygidae is supported by one disputable synapomorphy of the remaining Neuroptera, the presence of paraglossae in adults.     

The adult head structures of Tipulomorpha (Diptera,Insecta) and their phylogenetic implications

Schneeberg, K. and Beutel, R.G. 2011. The adult head structures of Tipulomorpha (Diptera, Insecta) and their phylogenetic implications. —Acta Zoologica (Stockholm) 92 : 316–343. Head structures of adults of Tipula paludosa, Limonia sp. and Trichocera saltator were examined and described. The results are compared with conditions found in other dipterans and other antliophoran groups, notably Nannochoristidae. Several potential synapomorphies of a dipteran–nannomecopteran–siphonapteran clade are present in Tipuloidea and Trichocera, the labro‐epipharyngeal food channel, the loss of the galea and the postpharyngeal pumping apparatus. The sensorial field of the maxillary palpomere 3, a potential dipteran–nannomecopteran synapomorphy, is also present but modified. The presence of M. clypeolabralis, labellae and mandibular stylets are groundplan apomorphies of Diptera, with secondary loss of the mandibles in Tipuloidea, Trichoceridae and many other groups. Tipuloidea is supported by the origin of M. tentorioscapalis anterior on the head capsule, the reduction of M. frontobuccalis anterior and the loss of the ocelli. The reduced tentorium, the origin of two further antennal muscles on the head capsule, the maxillary sensorial field with sensilla in individual pits, the lacking dorsal prelabial concavity and the unpaired salivary channel entering the head are apomorphies of Tipulidae. Closer affinities of Tipulidae and Cylindrotomidae are suggested by pseudotracheae of the advanced type, which have evolved independently in this lineage. The results do neither support a basal placement of Tipuloidea nor close affinities with Brachycera.     

The rare Chrysopidae (Neuroptera) of southwestern Europe

Quantitative surveys of the chrysopid fauna from southwestern Europe, namely the Iberian and Italian peninsulas, France south of 46° N, and the west-Mediterranean Islands, were analysed. A total of 56 species of Chrysopidae were reported, of which three species were abundant. These, Chrysoperla carnea (Stephens, 1836) sensu lato, Dichochrysa prasina (Burmeister, 1839) and D. flavifrons (Brauer, 1850), comprised a large percentage of the specimens. For the rarer species, comments are made on their distributions, the enhanced geographic range of exotic ones, and on levels of endemism and stenotopy.     

The First Mitochondrial Genomes of Antlion (Neuroptera: Myrmeleontidae) and Split-footed Lacewing (Neuroptera: Nymphidae), with Phylogenetic Implications of Myrmeleontiformia

In the holometabolous insect order Neuroptera (lacewings), the cosmopolitan Myrmeleontidae (antlions) are the most species-rich family, while the closely related Nymphidae (split-footed lacewings) are a small endemic family from the Australian-Malesian region. Both families belong to the suborder Myrmeleontiformia, within which controversial hypotheses on the interfamilial phylogenetic relationships exist. Herein, we describe the complete mitochondrial (mt) genomes of an antlion (Myrmeleon immanis Walker, 1853) and a split-footed lacewing (Nymphes myrmeleonoides Leach, 1814), representing the first mt genomes for both families. These mt genomes are relatively small (respectively composed of 15,799 and 15,713 bp) compared to other lacewing mt genomes, and comprise 37 genes (13 protein coding genes, 22 tRNA genes and two rRNA genes). The arrangement of these two mt genomes is the same as in most derived Neuroptera mt genomes previously sequenced, specifically with a translocation of trnC. The start codons of all PCGs are started by ATN, with an exception of cox1, which is ACG in the M. immanis mt genome and TCG in N. myrmeleonoides. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA, with the exception of trnS1(AGN). The secondary structures of rrnL and rrnS are similar with those proposed insects and the domain I contains nine helices rather than eight helices, which is common within Neuroptera. A phylogenetic analysis based on the mt genomic data for all Neuropterida sequenced thus far, supports the monophyly of Myrmeleontiformia and the sister relationship between Ascalaphidae and Myrmeleontidae.     

A new species of Stenobiella Tillyard (Neuroptera, Berothidae) from Australia

Stenobiella variolasp. n., a new species of beaded lacewing (Neuroptera: Berothidae), is described and figured from south-eastern Australia. A preliminary key to Stenobiella species is presented.     

Divided and undivided compound eyes in Ascalaphidae (Insecta, Neuroptera) and their functional and phylogenetic significance

The external morphology of the compound eyes of 13 species of the Ascalaphidae family (Insecta, Neuroptera) from Africa, Asia and Europe was studied in relation to the habitat, phylogeny and time of activity during the day. The six species with undivided eyes (Haplogleniinae) are nocturnal; four inhabit more or less open terrain, while two inhabit more or less dense vegetation. Of the seven species with divided eyes (Ascalaphinae), three are diurnal, one is crepuscular and nocturnal, and three are nocturnal. It was found that two of the diurnal species inhabit open terrain and open forest, and one inhabits dense vegetation; the crepuscular and nocturnal species inhabits open terrain; and two of the nocturnal species inhabit open terrain, while one inhabits dense vegetation. The results are discussed in relation to the hypothesis that divided eyes evolved from undivided eyes, originally serving as an adaptation to daytime vision in open terrain.     

The larval head of Nevrorthidae and the phylogeny of Neuroptera (Insecta)

External and internal head structures of larvae of Nevrorthidae were described in detail. The results were compared to conditions found in other representatives of Neuroptera and the other two neuropterid orders. The cladistic analysis supported the monophyly of Neuroptera, Neuroptera exclusive of Nevrorthidae, Hemerobiiformia, and Myrmeleontiformia. Neuroptera exclusive of Nevrorthidae are supported by the formation of an undivided postmentum and the presence of cryptonephric Malpighian tubules. The highly specialized articulation of the neck (Rollengelenk) and the absence of a salivary duct are autapomorphies of Nevrorthidae. Ithonidae and Polystoechotidae form a clade and are the sister group of the remaining Hemerobiiformia, which are characterized by the complete lack of a gula and a terminal filament of the antenna. Within this lineage, a clade comprising Mantispidae, Dilaridae, Berothidae, and Rhachiberothidae is well supported. Larvae of Myrmeleontiformia are characterized by a complex transformation of head structures, with a hypostomal bridge, a small triangular gula, largely reduced maxillary grooves, and anteriorly shifted posterior tentorial grooves. The slender finger‐like mid‐dorsal apodeme is another autapomorphy of the group. Psychopsidae are placed as the sister group of the remaining Myrmeleontiformia, which are characterized by a conspicuous, protruding ocular region (often less distinct or even absent in Nemopteridae). Ascalaphidae are the sister group of Myrmeleontidae. Larvae of both families share the fusion of the tibia and tarsus in the hind leg. The larval characters analysed were not sufficient for full resolution of the myrmeleontiform and hemerobiiform lineages. The position of several families such as Osmylidae, Sisyridae, and Coniopterygidae remains uncertain. The results are in agreement with an aquatic ancestor of Neuroptera and secondarily acquired terrestrial habits within the lineage (Neuroptera exclusive of Nevrorthidae), and another invasion of the aquatic environment by Sisyridae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 533–562.     

Comparative morphological assessment and phylogenetic significance of the wing base articulation in Psylloidea (Insecta,Hemiptera, Sternorrhyncha)

The wing articulation sclerites, as well as wing base environment, of phylogenetically distant Psylloidea taxa were examined by optical and electron microscopy in order to estimate the phylogenetic significance of observed morphological patterns. The basiradial bridge is strongly developed and links the fused humeral plate, basisubcostale, basiradiale and second axillary sclerite to the fused veins R + M + Cu. The proximal median plate has a vertical orientation, which may have a role in moving the wing forward and backward. The weak sclerotization posteriad of the second axillary sclerite and anteriad to the third axillary sclerite facilitates the backward movement of the wing. The horizontal hinge (= basal hinge), the vertical hinge and the torsional hinge are the most important fold- and flexion-lines for the mobility of the wing, whereas humeral folds and the anterior axillary fold-line play a minor role. The basalare presents two horns or processes that are autapomorphic traits for the superfamily Psylloidea. The monophyly of Psylloidea is also supported by the absence of the subalare, of the median notal wing process and of the anterior arm of the third axillary sclerite (lacking articulation with second axillary sclerite). Major interspecific variations are observed in tegula, first axillary sclerite and basalare shape and size. The second distal median plate is absent in Homotoma ficus (Homotomidae) and Glycaspis brimblecombei (Spondyliaspidinae), whereas it is present in Calophya schini (Calophyidae) and Psylla buxi (Psyllinae/Arytaininae); the presence of this sclerite could be a synapomorphy linking Calophyidae and the “psyllid assemblage”.     

The sperm structure of <Emphasis Type="Italic">Galloisiana yuasai</Emphasis> (Insecta,Grylloblattodea) and implications for the phylogenetic position of Grylloblattodea

The sperm ultrastructure of the Grylloblattodea Galloisiana yuasai was described and the sperm characters were comparatively examined in several orthopteroid insect orders for inferring the phylogenetic placement of the Grylloblattodea. The spermatozoa of G. yuasai are joined in bundles (spermatodesms) containing 200 units. Major features of these spermatozoa include a monolayered acrosome, a 9+9+2 axoneme with 16-pfs accessory microtubules and expanded intertubular material, and an evident “centriole adjunct”. The diffused material observed between the axoneme and the mitochondrial derivatives is considered to be an extension of the three connecting bands observed in other orthopteroid taxa, similar to what happens in some orthopteran lineages. The presence of the connecting bands, even though modified in G. yuasai, suggests that the Grylloblattodea are to be placed in a clade with Mantophasmatodea, Mantodea and Orthoptera.     

The ovipositor apparatus of basal Hymenoptera (Insecta): phylogenetic implications and functional morphology

The skeleto‐musculature of the ovipositor apparatus and the external sculpture of the 1st and 2nd valvulae was studied in representatives from all ‘symphytan’ families. Nineteen informative characters were coded and scored. The distribution of character states are discussed with reference to recent cladistic treatments of the Hymenoptera. Putative autapomorphies of the Hymenoptera are the presence of cordate apodemes on T9 and basal articulations and associated musculature between the 2nd valvifers and the 2nd valvulae. It is a ground plan feature of the order to have the gonocoxites of abdominal segment 8 fused with the gonangula. The configuration of the musculature of the ovipositor apparatus did not display much variation among the taxa examined, except within the Pamphilioidea. There is considerable variation in the external ovipositor sculpture within the Tenthredinoidea. Putative synapomorphies for the tenthredinoid families except the Blasticotomidae are the presence of alternating strongly and weakly sclerotized zones on the first and/or second valvulae and the presence of serrulae on the sawteeth. The presence of transverse rows of large ctenidia on the 1st valvulae is an autapomorphy of the Diprionidae. Fusion of the 2nd valvifers and the 3rd valvulae is a synapomorphy for the Argidae + Pergidae. The ovipositor apparatus of the Pamphilioidea is highly derived, putative autapomorphies being the close association between T9 and the first valvifers, the reduction of the distal parts of the 1st valvulae, and the fusion of the 2nd valvulae for their entire length. The changes in the ovipositor apparatus of Pamphilioidea are associated with a decrease in the amount of work it has to perform during ovipositing, as the eggs are placed predominantly externally on the substrate. The ovipositor apparatus of the ‘Siricoidea’ is enlarged and modified for ovipositing into wood. Putative synapomorphies of the ‘Siricoidea’ + Orussidae + Apocrita are the presence of sawteeth only distally on the ovipositor and elongation of the cordate apodemes of T9.     

Developmental pattern of the bony tentorium of spider monkeys (Ateles)

Based on their developmental patterns, the bony tentorium (BT) and bony falx (BF) of mammals can be classified into two types, the carnivoran type and the dolphin type. The former develops as part of the skull bones during the fetal period and is already completed at birth, while the latter is gradually formed by ossification in the tentorium cerebelli (TC) and falx cerebri (FC) during the course of aging. The BT of spider monkeys is assigned to the dolphin type.     

Sperm ultrastructure and spermiogenesis of Coniopterygidae (Neuroptera, Insecta)

The spermiogenesis and the sperm ultrastructure of several species of Coniopterygidae have been examined. The spermatozoa consist of a three-layered acrosome, an elongated elliptical nucleus, a long flagellum provided with a 9+9+3 axoneme and two mitochondrial derivatives. No accessory bodies were observed. The axoneme exhibits accessory microtubules provided with 13, rather than 16, protofilaments in their tubular wall; the intertubular material is reduced and distributed differently from that observed in other Neuropterida. Sperm axoneme organization supports the isolated position of the family previously proposed on the basis of morphological data.     

Complete mitochondrial genome of Bactrocera ritsemai (Insecta: Tephritidae) and phylogenetic relationship with its congeners and related tephritid taxa

Bactrocera ritsemai is a dacine fruit fly found in Indonesia. We report here the complete mitogenome of this fruit fly from Lombok, Indonesia determined by Illumina MiSeq sequencing and its phylogenetic relationship with its congeners and related tephritid taxa. The whole mitogenome of B. ritsemai had a total length of 15,927 bp, comprising 37 genes – 13 protein-coding genes (PCGs), 2 ribosomal ribonucleic acid (rRNA) and 22 transfer ribonucleic acid (tRNA) genes – and a control region (D-loop). Of the PCGs, 6 (atp6, cob, cox2, cox3, nad4, nad4l) had ATG start codon, 4 (nad2, nad3, nad5, nad6) had ATT, and one each had ATA (nad1), GTG (atp8) and TCG (cox1). Seven PCGs (atp6, atp8, cox2, cox3, nad2, nad4l, nad6) had TAA stop codon, 3 (cob, nad3, nad4) had TAG, and 3 had incomplete stop codon (cox1 – TA; nad1, nad5 – T). The TΨC-loop of tRNA was absent in trnF while trnS1 lacked the DHU-loop. Phylogenetic analysis based on 15 mt-genes (13 PCGs + 2 rRNA genes) indicated B. ritsemai forming a sister group with B. umbrosa and the subgenus Bactrocera was monophyletic. The genera Bactrocera and Zeugodacus were monophyletic while the subfamilies Dacinae and Tephritinae were paraphyletic. A broader taxa sampling of the Tephritidae is needed to better elucidate the phylogenetics and systematics of the tribes and subfamilies of tephritid fruit flies.     

The antennae of neopseustid moths: Morphology and phylogenetic implications, with special reference to the sensilla (Insecta, Lepidoptera, Neopseustidae)

The antennae of Lepidoptera Neopseustidae were examined with the scanning electron microscope. The studied species, Nematocentropus cfr. omeiensis, Neopseustis meyricki, Synempora andesae, Apoplania valdiviana and Apoplania penai possess nine types of antennal flagellum sensilla: multiporous large sensilla basiconica, multiporous thin sensilla basiconica, multiporous small sensilla basiconica, multiporous sensilla trichodea, multiporous sensilla coeloconica; uniporous sensilla chaetica; aporous sensilla chaetica, aporous stylus-shaped sensilla chaetica, aporous sensilla styloconica.The multiporous sensillum type here termed “multiporous large sensillum basiconicum” is unknown from other Lepidoptera and probably constitutes an autapomorphy of the family Neopseustidae. This sensillum type is remarkable by having a single base in female Apoplania and Synempora while in male Apoplania it has a bifid or trifid base, and in male Synempora it is composed of two or three incompletely separated hairs. This may be the first recorded example of a sexually dimorphic lepidopteran sensillum type. The stylus-shaped sensillum chaeticum is a primitive type which occurs only in some lower Lepidoptera.     

Cephalic morphology of Hymenopus coronatus (Insecta: Mantodea) and its phylogenetic implications

External and internal head structures of the mantodean Hymenopus coronatus are examined and described in detail. The results are elaborately compared with the literature. Strong crests on the anterior tentorial arms that articulate with the subantennal suture, a parietal suture and glossae and paraglossae with anteriorly bent tips are proposed as new potential apomorphies for Mantodea while a head capsule being wider than long, enlarged compound eyes, the presence of a frontal shield or scutellum, lateral lobes in the anterior tentorial arms, the presence of a transverse and an interantennal suture and the reduction of the mentum are confirmed as apomorphies, As potential apomorphies for Dictyoptera the reduction of Musculus tentoriobuccalis lateralis (M. 49) is newly presented and a “perforate” tentorium, lacinial incisivi that are located in a galeal pouch and the presence of a postmola are confirmed. The present study shows the value of cephalic morphology for phylogenetic analysis but also points out that further studies including evolutionary key taxa are essential for resolving the evolutionary adaptations among dictyopterans.     

Head morphology of Caurinus (Boreidae, Mecoptera) and its phylogenetic implications

External and internal head structures of Caurinus dectes were examined and described in detail. The features are compared to conditions found in other groups of Antliophora. Caurinus is obviously crucial for the reconstruction of the mecopteran and antliophoran groundplan. It displays a remarkable series of plesiomorphic character states such as a complete clypeolabral suture, the presence of M. hypopharyngomandibularis (M. 13) and M. frontohypopharyngalis (M. 41), a subdivided clypeus, a short head without rostrum, a dorsal tentorial arm attached to the head capsule, the absence of a cranial dilator of the antenna, and large mandibles with a well developed apical tooth, two distinct subapical teeth, and a basal molar part. The first three plesiomorphic features render potential autapomorphies of Mecoptera in the traditional sense invalid. Autapomorphies of Caurinus are the distinctly flattened labrum, the absence of the labroepipharyngeal muscle, the very large size of M. 13, the strongly enlarged penultimate palpomeres, the partition of M. 41, the very strongly developed precerebral sucking chamber, strongly curved optic lobes, the presence of a large protocerebral extension in the genal region and deep posterior excavations of the protocerebrum. The maxillolabial plate, the absence of cardines as separate structures, the reduction of ocelli, and the origin of maxillary palp muscles on a median ridge or area of the maxillolabial plate are likely autapomorphies of Boreidae. Another potential autapomorphy of the family is the presence of longitudinal furrows on the mandibles. However, they are absent in Boreus. The thick strongly sclerotised, median ridge of the maxillolabial plate, the missing retractibility of the prementum, the absence of extrinsic labial muscles, and the presence of a median ridge on the prepharyngeal roof suggest a clade Boreus + Hesperoboreus. The origin of extrinsic maxillary muscles from the clypeus has probably evolved independently in Boreus and Hesperoboreus, and in Panorpa, respectively. The absence of M. craniolacinialis and the presence of a row of several subapical mandibular teeth are autapomorphies of Boreus. The presence of a specific intrinsic muscle of the salivary duct and a membranous galea enclosing the labrum and mandibular base are derived features shared by Boreidae and Pistillifera (galea absent in Nannochorista, Siphonaptera and Diptera). The loss of M. frontolabralis (M. 8) is a potential apomorphy of Mecoptera incl. Siphonaptera. A sister group relationship between Boreidae and Siphonaptera is not supported by characters of the adult head. Head structures of Siphonaptera are extremely modified in correlation with ectoparasitic habits.     

The sperm ultrastructure of Caurinus dectes Russell (Mecoptera: Boreidae) and its phylogenetic implications

The sperm structure of the enigmatic mecopteran species Caurinus dectes (Boreidae) is described for the first time. Diagnostic features are the bi-layered acrosome, a cylindric nucleus provided with two longitudinal opposite grooves, and a simple 9 + 2 axoneme which degenerates in the posterior tail end. The results are conform with the monophyly of Mecoptera including Boreidae. A possible autapomorphy of the order is the presence of the two longitudinal opposite grooves along the nucleus, and the presence of two electron-dense fibres beneath the axoneme. Some apparently plesiomorphic features are preserved in the sperm of Caurinus. Features characterizing the distal part of the flagellum, including the presence of an axial cylindrical structure and the distinctive type of axoneme degeneration, are potential synapomorphies of Caurinus and Boreus, i.e. autapomorphic traits of Boreidae.     

Chromosome numbers in antlions (Myrmeleontidae) and owlflies (Ascalaphidae) (Insecta,Neuroptera)

A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies.