Phylogenetics and temporal diversification of the earliest true flies (Insecta: Diptera) based on multiple nuclear genes

Abstract Relationships among families of the lower Diptera (formerly suborder ‘Nematocera’) have been exceptionally difficult to resolve. Multiple hypotheses based on morphology have been proposed to identify the earliest lineages of flies and place the phylogenetic origin of the higher flies (Brachycera), but convincing support is limited. Here we resolve relationships among the major groups of lower Diptera using sequence data from four nuclear markers, including both ribosomal (28S rDNA) and protein‐coding (CAD, TPI and PGD) genes. Our results support both novel and traditional arrangements. Most unexpectedly, the small, highly‐specialized family Deuterophlebiidae appears to be sister to all remaining Diptera. Other results include the resolution of the traditional infra‐orders Culicomorpha (including a novel superfamily Simulioidea = Thaumaleidae + Simuliidae), Tipulomorpha (Tipulidae sensu lato + Trichoceridae) and Bibionomorpha sensu lato. We find support for a limited Psychodomorpha (Blephariceridae, Tanyderidae and Psychodidae) and Ptychopteromorpha (Ptychopteridae), whereas the placement of several enigmatic families (Nymphomyiidae, Axymyiidae and Perissommatidae) remains ambiguous. According to genetic data, the infra‐order Bibionomorpha is sister to the Brachycera. Much of the phylogenetic signal for major lineages was found in the 28S rDNA gene, whereas protein‐coding genes performed variably at different levels. In addition to elucidating relationships, we also estimate the age of major lower dipteran clades, based on molecular divergence time estimates using relaxed‐clock Bayesian methods and fossil calibration points.     

A phylogenetic interpretation of the Brachycera (Diptera) based on the larval mandible and associated mouthpart structures

Abstract. Based on outgroup comparison, the various components of the larval mandible of the Brachycera and their homologies are described. The final instar larval mandible of the Brachycera ground plan is comprised of a distal pointed hook and an inverted 'U'-shaped basal sclerite. The phylogenetic implications of the larval mandibular homologies and associated mouthpart structures for the current cladistic hypotheses of the Nematocera (Wood & Borkent, 1989) and orthorrhaphous Brachycera (Woodley, 1989) are evaluated.
A cladistic analysis of larval mouthpart characters largely supports the hypotheses of Wood & Borkent and Woodley. The presence of a pharyngeal filter is tentatively proposed as a synapomorphy of the Diptera exclusive of the Tipulomorpha and Bibionomorpha. Evidence is presented supporting a sister-group relationship between the Psychodomorpha ( sensu Wood & Borkent, 1989) and the Brachycera. The placement of the Pantophthalmidae in the Stratiomyomorpha is supported by the apomorphic development of the mandibular-maxillary complex and pharyngeal filter with posterior grinding mill. Additional larval mouthpart characters are proposed supporting the concept of the Eremoneura (Empidoidea + Cyclorrhapha). The ground plan of the Empidoidea appears to be characterized by the apomorphic development of a four-component mandible, in which the basal sclerite is subdivided into two connecting sclerites and a ventral sclerite. Morphological evidence is presented supporting the mandibular origin of the mouthhooks of the Cyclorrhapha.     

Phytogeny of the nematocerous families of Diptera (insecta)

The relationships of the nematocerous families of Diptera are cladistieally analysed using the parsimony programs PAUP and Hennig86. An extensive review, as well as a data matrix, is presented for 98 almost exclusively morphological characters (larva, 56; pupa, 6; adult, 36). Four infraorders are recognized, viz , Ptychopteromorpha, Culicomorpha, Blephariceromorpha, Bibionomorpha, and a clade containing the 'higher Nematocera' and Brachycera. Traditionally the family Nymphomyiidae or the infraorder Tipulomorpha (=Tipulidae, with or without Trichoceridae) are considered the most basal clade of the extant Diptera. On the basis of our cladistic analysis it is suggested that the Ptychopteromorpha-Culicomorpha clade is the sister-group of all other extant Diptera. We provide evidence that the Axymyiidae are part of a monophyletic Bibionomorpha. The latter infraorder is proposed as the sister-group of the higher Nematocera and Brachycera. We transfer the Tipulidae (Tipulomorpha) to the higher Nematocera, at a position next to Trichoceridae and near the Anisopodidae-Brachycera lineage. Previous hypotheses concerning nematocerous relationships are reviewed.     

The male postabdomen of the "ancestral" archostematan beetle Tetraphalerus bruchi Heller, 1913 (Ommatidae) and its phylogenetic significance

External and internal features of the male postabdomen of Tetraphalerus bruchi were examined with a broad spectrum of morphological techniques and are described in detail. The conditions found in males of Tetraphalerus are compared to those in other archostematan beetles and members of other coleopteran suborders. The far-reaching reduction of the sternite I, structural modifications of sternite II, the retracted condition of the terminal segments, and ventromedially fused apodemes arising from the anterior margin of tergite IX are likely autapomorphies of Coleoptera. The male postabdomen of Tetraphalerus is less derived than in most other groups of Coleoptera. The sclerotized elements are symmetrical. In contrast to earlier statements on the archostematan male genital apparatus a distinctly developed, sclerotized basal piece is present. The aedeagus is trilobed and all elements of the copulatory apparatus are distinct. The muscular equipment is simple and moderately developed. All muscles (except the transverse muscles 61 and 62) occur pairwise and symmetrically. The distinct increase of the number of postabdominal muscles in representatives of the higher lineages of Coleoptera is likely linked with a torsion of the copulatory apparatus, which also results in asymmetries of the sclerotised parts. The testes of Tetraphalerus are long, multi-coiled tubes like in other archostematans, Myxophaga (Torridincola) and Adephaga. The presence of a deep notch on the parameres is a synapomorphy of Tetraphalerus and Omma. Curved parameres, a shortened distal portion, and a distinctly shortened penis are potential synapomorphies of Omma rutherfordi and Omma mastersi. The large size of the sclerotized part of the phallobase ('basal piece') and the division of the sclerotization of sternum IX are potential ground-plan autapomorphies of Archostemata, with secondary modification of the latter feature in Cupedidae. The reduced condition of the sclerotization of sternum VIII is an apomorphic condition which has likely evolved independently in Tetraphalerus and Paracupes. Further anatomical investigation of the male genital apparatus of Coleoptera and holometabolous insects in general is required for a reliable morphological and phylogenetic interpretation. Concerning the presence or absence of particular sclerotizations (e.g., 'basal piece' of phallobase) histological section series and Confocal Laser Scanning Microscopy can add more precise information to what can be observed using permanent preparations of macerated specimens.     

Evolution and phylogeny of the Diptera: a molecular phylogenetic analysis using 28S rDNA sequences

Portions of the large ribosomal subunit RNA gene (28S rDNA) encompassing the D1 and the D7 region were obtained from 16 dipteran species and families to reconstruct early phylogenetic events in the order Diptera. For outgroup comparison, the corresponding sequences were used from representative taxa of the Siphonaptera, Mecoptera, and Lepidoptera. A subset of 488 unambiguously alignable sites was analyzed with respect to important sequence evolution parameters. We found (1) sequence variability is significantly higher in double-stranded sites than in single-stranded sites, (2) transitions are close to saturation in most pairwise sequence comparisons, (3) significant substitution rate heterogeneity exists across sites, and (4) significant substitution rate heterogeneity exists among lineages. Tree reconstruction was carried out with the neighbor joining, maximum parsimony, and maximum likelihood methods. Four major subgroups are consistently and robustly supported: the Brachycera, the Culicomorpha, the Tipulomorpha sensu stricto, and the hitherto controversial Bibionomorpha sensu lato, which includes the families Sciaridae, Mycetophilidae, Cecidomyiidae, Bibionidae, Scatopsidae, and Anisopodidae. The phylogenetic relationships within or among these subclades and the positions of the families Psychodidae and Trichoceridae were not robustly resolved. These results support the view that the mouthparts of extant dipteran larvae evolved from a derived ground state characterized by subdivided and obliquely moving mandibles. Furthermore, sequence divergence and the paleontological record consistently indicate that a period of rapid cladogenesis gave rise to the major dipteran subgroups.     

The mushroom bodies of the lower nematocera: A link between those of the higher diptera and other mecopteroids

Nematoceran Diptera are nonuniform in the structure of their mushroom bodies. Members of the more basal families (Ptychopteridae, Pediciidae, and Tipulidae) have bipartite mushroom bodies, characteristic of members of the other mecopteroid complex orders. In members of Bibionomorpha (Bibionidae and Anisopodidae), tripartite mushroom bodies have been found characteristic of Brachycera Orthorrhapha.     

The female postabdomen of the enigmatic Nannochoristidae (Insecta: Mecopterida) and its phylogenetic significance

Hünefeld, F. and Beutel, R.G. 2011. The female postabdomen of the enigmatic Nannochoristidae (Insecta: Mecopterida) and its phylogenetic significance. —Acta Zoologica (Stockholm) 00: 1–8. External and internal features of the female postabdomen of Nannochorista neotropica are described in detail. The conditions found in females of Nannochoristidae come closest to the ground plan of Mecopterida. This lineage is characterised by telescoping postabdominal segments, a presumptive autapomorphic feature that is modified in some antliophoran groups, but displayed by the nannochoristid species in a typical manner. More potential autapomorphies of Mecopterida, all present in Nannochoristidae, are the neo‐formation of an intersegmental muscle, a transverse muscle spanning between the genital appendages of segment VIII, a muscle connecting these appendages and the genital chamber and the loss of an intersegmental muscle. Plesiomorphic features of Nannochoristidae are the presence of paired genital appendages on segments VIII and IX. Information on the egg‐depositing substrates of the females is not available. The telescoping postabdomen is suitable for oviposition in soft substrates such as moist soil, or rotten plant materials in the riparian zone, and this is possibly a ground‐plan feature of Mecopterida. The results of recent phylogenetic analyses based on morphological data support a placement of Nannochoristidae in Antliophora, whereas the exact position of the group remains ambiguous. No characters of the female postabdomen were found supporting the monophyly of Mecoptera as conventionally circumscribed, that is Nannochoristidae + Boreidae + Pistillifera.     

The male postabdomen of Stolotermes inopinus: a termite with unusually well-developed external genitalia (Dictyoptera: Isoptera: Stolotermitinae)

Klass, K.‐D., Thorne, B. L. and Lenz, M. 2000. The male postabdomen of Stolotermes inopinus: a termite with unusually well‐developed external genitalia (Dictyoptera: Isoptera: Stolotermitinae). —Acta Zoologica (Stockholm) 81 : 121–130 Stolotermes inopinus has large external male genitalia (phallic lobe), which contrast with the small genital papillae or lack of external genitalia of other Isoptera. As in the genital papilla of Mastotermesdarwiniensis, a ventral sclerite pair is present, the gonopore is located ventroterminally on the phallic lobe, and the genital area is entirely symmetrical – suggesting that this may be the groundplan condition of Isoptera. The relations of the phallic lobe to surrounding components like the subgenital plate, paraprocts, and certain muscles and nerves indicate that the lobe of S. inopinus is homologous with the phallomeres of other Dictyoptera. The bilateral symmetry and simple structure, however, are in strong contrast to the asymmetry and high complexity found in male genitalia of Blattaria and Mantodea. The postabdominal nervous system of S. inopinus resembles that of the cockroach Periplaneta americana. Indications are given that the Stolotermitinae are related to the Kalotermitidae, Rhinotermitidae, and Termitidae rather than to the Termopsinae.     

The dipteran sperm tail: ultrastructural characteristics and phylogenetic considerations

The sperm tail from representatives of several families of Diptera has been examined by high resolution electron microscopy and a computer analysis that improved the visualization of recorded patterns. A considerable variability in sperm tail structure is found within Diptera, and is actually greater than that of any other insect order. The 'generalized insect sperm axoneme'. which is characterized as a 9+9+2 axoneme and by the accessory microtubules having 16 protofilaments, was found only in some dipterans; these are members of Mycetophilidae. From this fact we conclude that Mycetophilidae is likely to be the most primitive extant dipteran group. Another mycetophilid, Boletina , was seen to have accessory tubules with 15 protofilaments as have members of families Dixidae, Chironomidae, Culicidae, and Bibionidae. The last two families have spermatozoa of a type designated as 9+9+'1' there is a central rod rather than two microtubules. We regard this 9+9+'1'pattern with 15 protofilaments to represent a synapomorphic feature. Representatives of the neatoceran families Tipulidae and Trichoceridae have accessory tubules with 13 protofilaments as do examined members of several brachyceran families. Brachycera is hence likely to be derived from the vicinity of the tipulid family. The intertubular material is small in Mycetophilidae and most nematoceran groups, whereas in Tipulidae and Brachycera it is enlarged; here it bridges the space between the accessory tubules and contains various inclusions.     

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.     

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 morphology and evolution of the female postabdomen of Holometabola (Insecta)

In the present article homology issues, character evolution and phylogenetic implications related to the female postabdomen of the holometabolan insects are discussed, based on an earlier analysis of a comprehensive morphological data set. Hymenoptera, the sistergroup of the remaining Holometabola, are the only group where the females have retained a fully developed primary ovipositor of the lepismatid type. There are no characters of the female abdomen supporting a clade Coleopterida + Neuropterida. The invagination of the terminal segments is an autapomorphy of Coleoptera. The ovipositor is substantially modified in Raphidioptera and distinctly reduced in Megaloptera and Neuroptera. The entire female abdomen is extremely simplified in Strepsiptera. The postabdomen is tapering posteriorly in Mecopterida and retractile in a telescopic manner (oviscapt). The paired ventral sclerites of segments VIII and IX are preserved, but valvifers and valvulae are not distinguishable. In Amphiesmenoptera sclerotizations derived from the ventral appendages VIII are fused ventromedially, forming a solid plate, and the appendages IX are reduced. The terminal segments are fused and form a terminal unit which bears the genital opening subapically. The presence of two pairs of apophyses and the related protraction of the terminal unit by muscle force are additional autapomorphies, as is the fusion of the rectum with the posterior part of the genital chamber (cloaca). Antliophora are supported by the presence of a transverse muscle between the ventral sclerites of segment VIII. Secondary egg laying tubes have evolved independently within Boreidae (absent in Caurinus) and in Tipulomorpha. The loss of two muscle associated with the genital chamber are likely autapomorphies of Diptera. The secondary loss of the telescopic retractability of the postabdomen is one of many autapomorphies of Siphonaptera.     

中国蝼蛄属研究及一新种记述(直翅目,蝼蛄科)

给出了中国蝼蛄属的检索表,并描述了该属1新种G.mabiana sp.nov..新种与尼泊尔种类 G.pygmaea相似,但可以通过如下特征加以区分:径脉末端不分岔,翅室呈三角形,阳茎基片横向骨片的侧端尖锐;此新种还与河南蝼蛄G.henana相似,区别为:新种前翅超过第5节背板,后翅到达第4节背板后缘,而河南蝼蛄G.henana前后翅均未伸达腹部第4节背板后缘;新种前胸背板无心纹斑,河南蝼蛄G.henana有;新种阳茎侧突囊弯钩状,后者为弯月形.     

Scleritome construction,biofacies, biostratigraphy and systematics of the tommotiid Eccentrotheca helenia sp. nov. from the Early Cambrian of South Australia

Abstract: Large collections of Eccentrotheca helenia sp. nov. from the lower Cambrian Wilkawillina and Ajax limestones in the Arrowie Basin, South Australia, contain abundant low, cap‐shaped and high, laterally compressed isolated sclerites in addition to partially articulated tubular specimens. The scleritome of Eccentrotheca helenia sp. nov. is fully described for the first time and shown to be formed by ontogenetic fusion of sclerites into successively stacked sclerite rings, forming a larger, tubular structure. The apical termination of the tube is highly variable, but is primarily constructed by low, cap‐shaped sclerites and characterised by a central aperture of variable inclination. The adapical portion of the tube is predominantly constructed by high, laterally compressed sclerites, but individual sclerite rings can contain both cap‐shaped and laterally compressed sclerites along with sclerites of intermediate morphology. The apical aperture presumably housed organic structures for attachment to a hard substrate, but the scleritome also occasionally preserves small lateral perforations between fused sclerites, which may have served to stabilise the scleritome by providing additional points of anchorage. In the Arrowie Basin, E. helenia is found in association with archaeocyath‐microbial‐spongiomorph‐dominated bioherms and most likely inhabited pendant or cryptic habitats within these bioherms. Eccentrotheca‐like sclerites form an integral part of the scleritomes of many tommotiids which may confuse taxonomic analysis. Sclerites previously assigned to ‘E.’guano, consistently occur together with sclerites of Kulparina rostrata in stratigraphic intervals consistently older than strata hosting E. helenia. Rare fused specimens indicate that the sclerites of K. rostrata and ‘E.’guano belong to the same scleritome.     

The male postabdomen and genital apparatus of †Mengea tertiaria,a strepsipteran amber fossil (Insecta)

The male genital apparatus of a fossil insect including internal soft parts is described in detail for the first time. The conditions found in an approximately 42‐My‐old specimen of ?Mengea tertiaria embedded in Baltic amber are compared to what is found in other extinct and extant strepsipterans, notably members of the basal ‘Mengenillidae’ (probably paraphyletic). The postabdomen of ?Mengea is very similar to what is present in other fossil and extant members of Strepsiptera. Only few structural features vary within the group, but it differs strongly from the apparatus in other holometabolan lineages. The slender, exposed tergite IX, the complete absence of parameres, a sperm pump formed by a strongly developed muscularis (layers of mainly circular muscle fibres) around the proximal part of the ejaculatory duct and the presence of four specific muscles are potential autapomorphies of the Strepsiptera. A presumptive strepsipteran ground plan feature found in ?Mengea is the nearly straight, simple penis, which is also present in ?Protoxenos, ?Cretostylops, Bahiaxenos, Mengenilla, Eoxenos and Congoxenos. This strongly suggests that males of ?Mengea (and other stem group strepsipterans) copulated in a very similar way as males of extant members of the group with free‐living females (e.g. Mengenilla). In contrast, the penis of stylopidian males, which copulate with females parasitizing in pterygote hosts, is hook shaped. A sister group relationship between ?Mengea and Strepsiptera s.s. (extant groups) is supported by a distinctly weaker sclerotization of the abdominal tergites, compared to the corresponding sternites. The study of other stem group strepsipterans using μ‐computer tomography should have high priority. This technique has a great potential to facilitate morphological reconstruction and phylogenetic placement of amber fossils.     

The female abdomen of the viviparous earwig Hemimerus vosseleri (Insecta: Dermaptera: Hemimeridae), with a discussion of the postgenital abdomen of Insecta

The viviparous, epizoic African earwigs of the genus Hemimerus are currently regarded as the sister taxon of the remaining Dermaptera (Forficulina). Exoskeleton, musculature, and part of the nervous system of the female abdomen, from segment IV on, are described. The morphological interpretation and homology relations of most components are discussed, using previous and original data on Forficulina, Zygentoma, Ephemeroptera, Orthoptera and Dictyoptera as a comparative framework. In the mid-abdominal segments some interesting similarities with Zygentoma are indicated. Focal issues in the postgenital abdomen are the terminal dorsal sclerites, the cercal muscles, and the paraprocts and associated muscles. Earlier hypotheses on the dermapteran postabdomen (opisthomere and pseudocercus hypotheses) and results from ontogenetic studies are scrutinized. Some interesting features detected in female Hemimerus are the immobilization of terga VIII-X by means of a thick internal cuticle layer, the lack of dorsal muscles on these terga, the shift of some insertions of cercal and rectal muscles from tergum X to tergum IX, and minute pits on the venters IX and X that could be spiracle vestiges. Some of these features occur also in other Dermaptera. Some abdominal characters suggest that Hemimerus is nested within the Forficulina. The lack of the clasper-shape in the cerci is not a strong argument against this.     

Phylogenetic relevance of the genital sclerites of Neuropterida (Insecta: Holometabola)

Abstract Segment 9 of male Raphidioptera, comprising tergite, sternite, gonocoxites, gonostyli and gonapophyses, is a benchmark for homologies in the male and female terminalia of the three Neuropterida orders Raphidioptera, Megaloptera and Neuroptera. The segments relating to genitalia are 9, 10 and 11 in males and 7, 8 and 9 in females. Results from holomorphological and recent molecular cladistic analyses of Neuropterida agree in supporting the sister‐group relationships between: (1) the Raphidioptera and the clade Megaloptera + Neuroptera, and (2) the suborder Nevrorthiformia and all other Neuroptera. The main discrepancy between the results of these studies is the nonmonophyly of the suborder Hemerobiiformia in the molecular analysis. The monophyly of the Megaloptera (which has been repeatedly questioned) is further corroborated by a hitherto overlooked ground pattern autapomorphy: the presence of eversible sacs within the complex of the fused gonocoxites 11 in Corydalidae and Sialidae. The recently discovered paired complex of gonocoxites 10 (parameres) in Nipponeurorthus (Nevrorthidae) indicates that the curious apex of sternite 9 of Nevrorthus and Austroneurorthus is the amalgamation of the sclerites of gonocoxites 10 with sternite 9, interpreted as synapomorphic. In the molecular study, the Nevrorthidae, Sisyridae and Osmylidae branch off in consecutive splitting events, a result that is supported by the analysis of male genital sclerites reported here. Extraordinary parallel apomorphies (e.g. excessive enlargement and modification of gonocoxites 10 ending in a thread‐like ‘penisfilum’) in derived representatives of Coniopterygidae, Berothidae, Rhachiberothidae and Mantispidae corroborate the dilarid clade of the morphological analysis and leads us to hypothesize a sister‐group relationship of the Coniopterygidae with the dilarid clade. A re‐interpretation of the tignum of Chrysopidae as gonocoxites 11 means that the structure previously called the gonarcus represents the fused gonocoxites 9. In Hemerobiidae, the corresponding sclerite is consequently also homologized as fused gonocoxites 9. The enlargement of the lateral wings of the gonocoxites in both families is interpreted as a synapomorphy. Excessive enlargement of gonostyli 11 in the Polystoechotid clade and Myrmeleontiformia supports a sister‐group relationship of these two clades. The occurrence of certain serial homologues of female genitalia structures (gonocoxites and gonapophyses), such as the digitiform processus together with the flat appendices in segment 8 of certain Myrmeleontidae, or the wart‐like processus together with the flat circular sclerites in segment 7 of certain Berothidae, as well as the presence of gonocoxites 8 as pseudosternites in certain Nemopteridae and Coniopterygidae, are probably character reversals. The digitiform processus of tergite 9 (pseudogonocoxites) in Rhachiberothidae and Austroberothella (Berothidae) are either independently developed acquisitions with a function in oviposition, or are homologous sclerites, possibly of epipleurite origin.     

The phylogenetic relationships among infraorders and superfamilies of Diptera based on morphological evidence

Members of the megadiverse insect order Diptera (flies) have successfully colonized all continents and nearly all habitats. There are more than 154 000 described fly species, representing 10–12% of animal species. Elucidating the phylogenetic relationships of such a large component of global biodiversity is challenging, but significant advances have been made in the last few decades. Since Hennig first discussed the monophyly of major groupings, Diptera has attracted much study, but most researchers have used non‐numerical qualitative methods to assess morphological data. More recently, quantitative phylogenetic methods have been used on both morphological and molecular data. All previous quantitative morphological studies addressed narrower phylogenetic problems, often below the suborder or infraorder level. Here we present the first numerical analysis of phylogenetic relationships of the entire order using a comprehensive morphological character matrix. We scored 371 external and internal morphological characters from larvae, pupae and adults for 42 species, representing all infraorders selected from 42 families. Almost all characters were obtained from previous studies but required revision for this ordinal‐level study, with homology assessed beyond their original formulation and across all infraorders. We found significant support for many major clades (including the Diptera, Culicomorpha, Bibionomorpha, Brachycera, Eremoneura, Cyclorrhapha, Schizophora, Calyptratae and Oestroidea) and we summarize the character evidence for these groups. We found low levels of support for relationships between the infraorders of lower Diptera, lower Brachycera and major lineages of lower Cyclorrhapha, and this is consistent with findings from molecular studies. These poorly supported areas of the tree may be due to periods of rapid radiation that left few synapomorphies in surviving lineages.     

The female postabdomen and internal genitalia of the basal moth genus Agathiphaga (Insecta: Lepidoptera: Agathiphagidae): morphology and phylogenetic implications

The female postabdomen of Agathiphaga vitiensis terminates in a telescope‐type extensible oviscapt with an apial ‘oviscapt probe’ composed of fused segments behind VIII. Exceptionally within the Lepidoptera two pairs of long ‘anterior apophyses’ arise from segment VIII, from the dorsum and venter. Agathiphaga has the most elaborate postabdominal musculature recorded from female Lepidoptera, comprising 24 muscle sets of which nine may be family autapomorphies. Apophysis musculature does not permit unambiguous homologizing of the single anterior apophysis in Lepidoptera–Glossata with either the dorsal or ventral pair in Agathiphaga, but is compatible with an interpretation of the glossatan anterior apophyses as a composite formation. Nine muscle sets shared with rhyacophilid caddisflies are ascribed to the amphiesmenopteran ground plan. The spermathecal duct represents an intermediate stage between the simple type present in Micropterigidae and the ‘two‐compartment type’ characteristic of almost all other Lepidoptera. The spermatheca has no lagena. The bursa copulatrix is small and simple. Accessory glands are very large, simple sacs. There are 40 + ovarioles per ovary. A terminal cloaca is extremely short. The numerous ovarioles potentially support a sister‐group relationship between Agathiphagidae and all other Lepidoptera, whereas the spermathecal duct histology supports the alternative conservative placement of the family as sister group of all nonmicropterigid Lepidoptera. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 905–920.     

The larval head of Exechia (Mycetophilidae) and Bibio (Bibionidae) (Diptera)

Exechia and Bibio have retained several plesiomorphic groundplan features of Diptera and Bibionomorpha, including a fully exposed and sclerotized head capsule, the transverse undivided labrum, the absence of movable premandibles, and undivided mandibles without combs. The fusion of the hypostomal bridge with the head capsule and largely reduced antennae are derived features shared by both taxa. The absence of teeth at the anterior hypostomal margin is a potential autapomorphy of Bibionomorpha. A basal position of Anisopodidae is suggested by a number of plesiomorphies retained in this family. Apomorphies of Bibionomorpha excluding Anisopodidae are the reduction of tentorial elements, the partial fusion of the labrum and clypeus, one-segmented antennae, the absence of a separate submental sclerite, the loss of the labial palpus, and the reduction of the pharyngeal filter apparatus. Head structures of Bibio are largely unmodified. The subprognathous orientation is one of few autapomorphic features. In contrast, the mouthparts of Exechia are highly modified in correlation with the specialized food uptake. The rasping counterrotating movements of maxillae and mandibles with teeth oriented in opposite directions are carried out by strongly developed extensors and flexors of the paired mouthparts. The modified labium mechanically supports the “drill head” formed by the mandibles und maxillae. The necessary stability of the head capsule is provided by the hypostomal bridge which also compensates the far-reaching reduction of the tentorium.