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.     

Discovery of the genus Suhpalacsa Lefèbvre (Neuroptera: Ascalaphidae: Ascalaphinae) in Japan, with description of a new species

Suhpalacsa iriomotensis sp. nov. (Neuroptera: Ascalaphidae: Ascalaphinae), is described from Iriomotejima Island, Japan. This new species can be easily distinguished from other species of the genus by the unique ventrolateral prominences of the male ectoproct. This is the first record of the genus Suhpalacsa from Japan. The morphology of the male ectoproct and the monophyly of Suhpalacsa are discussed briefly.     

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.     

The egg, repagulum, and larva of Byas albistigma (Neuroptera: Ascalaphidae): morphology, behaviour and phylogenetic significance

Abstract The external morphology and habits of the larval instars of the Central American ascalaphid Byas albistigma (Walker) are described for the first time, and its eggs and repagula (abortive eggs) are compared to those of a Brazilian Byas sp. described by New (1971). In most respects, all immature stages of Byas are shown to be much like those of another neuroptyngine (entire-eyed) owlfly, Ascaloptynx furciger (McLachlan). However, larvae of Byas are arboreal rather than terrestrial and possess a number of important morphological characters that are more primitive than those seen in Ascaloptynx Shared features of the two genera that may constitute the ground plan of the Neuroptynginae are discussed in some detail and are weighted according to their primitive or derived status.     

Tibial combs in the Cydnidae (Hemiptera: Heteroptera) and their functional, taxonomic and phylogenetic significance

Tibial combs in representatives of the family Cydnidae are described in detail for the first time. The structure was studied in 98 species of 58 genera representing all the subfamilies, among them 16 species were investigated using scanning electron microscopic (SEM) techniques. In addition, Parastrachia japonensis (Scott, 1880) of the family Parastrachiidae, and two species of Dismegistus Amyot and Serville, 1843 (a genus of uncertain systematic position within Pentatomoidea) have also been studied. Morphological terminology is proposed for all the structures connected with tibial combs and the term 'the tibial comb complex' is suggested; its functional, taxonomic and phylogenetic significance is also discussed. The genera of Cydnidae can be classified into two groups depending on differences in the tibial comb complex, when it is present; moreover, its absence in the tribe Scaptocorini (Cephalocteinae) is demonstrated for the first time and is regarded as an autapomorphy of this tribe. Data on the occurrence of tibial combs in other families of true bugs (Hemiptera: Heteroptera) are also briefly reviewed, and an anagenetic trend in their evolution in terrestrial Heteroptera is hypothesized. The presence of tibial combs on all legs is regarded as the most plesiomorphic state.     

The larval head of Raphidia (Raphidioptera, Insecta) and its phylogenetic significance

External and internal head structures of larval representatives of Raphidiidae are described. The obtained data were compared to characters of other neuropterid larvae and to larval characters of representatives of other endopterygote lineages. Characters potentially relevant for phylogenetic reconstruction are listed and discussed. The larvae of Raphidioptera differ distinctly from other neuropterid larvae in their morphology. They are mainly characterised by autapomorphic and plesiomorphic character states and few features indicate systematic affinities with other groups. Endopterygote groundplan features maintained in Raphidioptera are the complete tentorium, the free labrum, the full set of labral muscles, the presence of four extrinsic antennal muscles, the three-segmented labial palpi, the presence of a full set of extrinsic maxillary and labial muscles, the presence of a salivarium, and possibly the high number of stemmata. Apomorphies likely correlated with predaceous habits are the long gula, the protracted maxillae, the longitudinal arrangement of extrinsic maxillary muscles, and the elongated prepharyngeal tube. Highly unusual, potentially autapomorphic features are the presence of a dorsal ligament of the tentorium and paired gland-like structures below the pharynx. A prognathous or very slightly inclined head and slender mandibles without mola are features shared by larvae of all orders of Neuropterida. The parallel-sided head is a potential synapomorphy of Raphidioptera and Megaloptera. A fully prognathous head with anteriorly shifted posterior tentorial grooves and the presence of a parietal ridge and a distinct neck region are features shared with Corydalidae. Characters of the larval head are not sufficient for a reliable placement of Raphidioptera.     

Ontogeny and optics of the eyes of the common prawn Palaemon (Palaemon) serratus (Pennant, 1777)

A brief review of the work on crustacean compound eyes is given. Two main types of eye have been recognized: apposition and superposition. The ontogeny of the eyes of the common prawn Palaemon serratus is examined using a variety of methods: photography of live specimens, histological sections, SEM and TEM. In common with other decapod larvae, the common prawn hatches with apposition eyes having circular lenses packed hexagonally. After metamorphosis the gradual squaring of the eye facets, begun during the larval phase, is completed. This is an essential prerequisite for the functioning of the facultative superposition reflecting optics found in long-bodied decapods (e.g. shrimps, prawns and lobsters) and some Anomura. The possible phylogenetical significance of superposition, reflecting optics is also discussed.     

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.     

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.     

Evolutionary trends and their functional significance in chasmopine trilobites

In response to environmental pressures, speciation within the Chasmopinae involved the attempt to minimise the anterior blind spot. This was attempted in four different ways: by positioning the eyes progressively closer to the glabella, in the Chasmops-Toxochasmops lineage; on the sides of the cephalon, in Bolbochasmops and Rollmops; by elevating and reducing the size of the eyes, in Scopelochasmops ; and by the development of very large eyes in species of Chasmops and Toxochasmops. Development of different eye morphologies resulted in complementary cephalic morphological changes, involving frontal lobe convexity, position and orientation of glabellar furrows, size of hypostome and overall cephalic shape. The strong selection pressure acting on eye form in order to minimise the anterior blind spot suggests that the Chasmopinae may have led a predatory mode of life.     

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.     

昆虫复眼形态结构及感光机制研究进展

复眼是昆虫的主要视觉器官,昆虫复眼形态、结构的研究是理解昆虫感光的基础。本文从昆虫复眼的外部形态、内部微观结构和功能以及对光的感受机制作一简要综述,且对今后昆虫复眼的研究方向进行了展望。     

The function and phylogenetic implications of the tentorium in adult Neuroptera (Insecta)

Despite several recent analyses on the phylogeny of Neuroptera some questions still remain to be answered. In the present analysis we address these questions by exploring a hitherto unexplored character complex: the tentorium, the internal cuticular support structure of the insect head. We described in detail the tentoria of representatives of all extant neuropteran families and the muscles originating on the tentorium using 3D microCT images and analyzed differences in combination with a large published matrix based on larval characters. We find that the tentorium and associated musculature are a source of phylogenetically informative characters. The addition of the tentorial characters to the larval matrix causes a basad shift of the Sisyridae and clearly supports a clade of all Neuroptera except Sisyridae and Nevrorthidae. A sister group relationship of Coniopterygidae and the dilarid clade is further corroborated. A general trend toward a reduction of the dorsal tentorial arms and the development of laminatentoria is observed. In addition to the phylogenetic analysis, a correlation among the feeding habits, the development of the maxillary muscles, and the laminatentoria is demonstrated.     

Ultrastructure of pigmented eyes in Dorvilleidae (Annelida,Errantia, Eunicida) and their importance for understanding the evolution of eyes in polychaetes

Among polychaetes, the errant forms are the only group known so far possessing true multicellular eyes in adults which are preceded by bicellular larval eyes in many species. Most likely, two pairs of such eyes showing a specific structure belong to the ground pattern of Errantia = Aciculata. However, these eyes have primarily been investigated in only two subgroups of Errantia, but data on the third main taxon, Eunicida, are available for only two taxa. In the present investigation, the eyes in two additional species of Eunicida, the dorvilleids Protodorvillea kefersteini and Schistomeringos neglecta, were studied. In P. kefersteini, usually described as possessing one pair of small eyes, two pairs could be detected, whereas in S. neglecta only one pair was found. Each eye is made up of rhabdomeric photoreceptor cells, pigment cells and unpigmented supportive cells. Lenses or vitreous bodies are absent. From their structure most likely all eyes represent adult eyes and even the small anterior eyes in P. kefersteini structurally resemble miniaturized adult eyes. Neither persisting larval eyes nor unpigmented rhabdomeric ocelli were found in the two species. The observations in Dorvilleidae confirm the hypothesis of a common origin of adult eyes in Errantia.     

The sperm structure of Embioptera (Insecta) and phylogenetic considerations

The sperm structure of two species of Embioptera, Embia savignyi Westwood 1837 and Aposthonia japonica (Okajima 1926), was studied. Spermatozoa of both species exhibit a monolayered acrosome and a layer of material surrounding the sperm cells for most of their length. The presence of a 9+9+2 axoneme provided with accessory microtubules with 16 protofilaments, two accessory bodies and two crystallized mitochondrial derivatives are characters shared with other polyneopteran taxa. The supposed close relationship between Embioptera and Phasmatodea is not supported by characters of the sperm ultrastructure.     

大草蛉成虫复眼的外部形态及其显微结构

用扫描电镜和光学显微镜观察了大草蛉Chrysopa pallens Ramber成虫复眼的外部形态及明、暗适应和性别对其显微结构的影响。结果发现：（1）其复眼呈半球形,位于头部两侧,略成“八”字形排列,单个复眼约由3 600个小眼组成,最前和最后小眼之间的夹角约为180°,最上和最下小眼之间的夹角约200°;（2）小眼主要由角膜、晶锥和6～8个小网膜细胞、基膜组成,外围环绕有2个初级虹膜色素细胞和6个次级虹膜色素细胞,基膜处有色素颗粒分布;（3）暗适应时,晶锥开裂程度较大,远端5～7个网膜细胞核向远端移动,与晶锥近端相接或接近,次级虹膜色素颗粒亦向远端移动包围晶锥;明适应时,晶锥开裂程度小或闭合,远端网膜细胞核向近端移动,透明带显现,大部分次级虹膜色素颗粒亦向近端移动分布在小网膜细胞柱周围,包被透明带;（4）在相同的明、暗适应下,雌、雄成虫复眼的显微结构无明显差异。结果表明大草蛉复眼为透明带明显的重叠象眼,其小眼不但具有次级虹膜色素颗粒纵向移动的常规调光机制,还存在晶锥开闭、远端网膜细胞核移动和基膜色素颗粒纵向扩散的调光新机制。     

Comparative study of sensilla and other tegumentary structures of Myrmeleontidae larvae (Insecta,Neuroptera)

Antlion larvae have a complex tegumentary sensorial equipment. The sensilla and other kinds of larval tegumentary structures have been studied in 29 species of 18 genera within family Myrmeleontidae, all of them with certain degree of psammophilous lifestyle. The adaptations for such lifestyle are probably related to the evolutionary success of this lineage within Neuroptera. We identified eight types of sensory structures, six types of sensilla (excluding typical long bristles) and two other specialized tegumentary structures. Both sensilla and other types of structures that have been observed using scanning electron microscopy show similar patterns in terms of occurrence and density in all the studied species (with few exceptions). The sensilla identified are: coeloconica, placoidea, basiconica, trichodea type I, trichodea type II, and campaniformia. All these sensilla have mechano- or chemosensorial functions. Some regions of the larval body have been studied using SEM for the first time, such as the surface of the food canal, which bears sensilla coeloconica, and the abdominal segment X, that bears three types of sensilla: coeloconica, basiconica, and campaniformia. Sensilla placodea are newly reported on antlion larvae, being present on the mandibular base, pronotum, mentum, and cardum. Also, new locations of sensilla coeloconica (e.g., on rastra) and sensilla campaniformia (e.g., on odontoid processes) are noted. A novel porous texture with chemoreceptor function has been identified in the base of mandibles. A mechanism of dentate-notched surfaces that anchor maxillae and mandible, reinforcing the food canal, is detailed. All these sensorial structures, in addition to ocular tubercles for light caption and their great muscular system, confer to these larvae an extraordinary predation capacity to success hunting and living in such harsh environments.     

A combined morphological and molecular phylogenetic analysis of Parthenocissus (Vitaceae) and taxonomic implications

Parthenocissus (the Virginia creeper genus, Vitaceae) consists of 13 species and shows a disjunct distribution between Asia and North America. We investigated the inflorescence structure, calyx morphology, appendages on the inner side of petals, leaf epidermis, pollen and seed characters throughout the genus. A combined phylogenetic analysis with 27 morphological and 4137 molecular characters was conducted and the result was largely congruent with that of the previous molecular work, but with higher resolution. The combined analysis identified two clades corresponding to the Asian and North American taxa. Parthenocissus feddei was resolved as closely related to the clade containing P. cuspidifera, P. heterophylla and P. semicordata. The four species share synapomorphies of having conspicuously raised veinlets, an obscurely five‐ (to eight‐) lobed calyx, appendages on the inner side of petals covering the entire length of anthers and foveolate pollen exine ornamentation. Within the Old World clade, the pentafoliolate species were weakly supported as more closely related to species with both simple and trifoliolate leaves. Furthermore, the ancestral states of tendril apices, inflorescence structure, appendages on the inner side of petals and exine ornamentation of pollen grains were reconstructed on the molecular strict consensus tree. The appendages on the inner side of petals and exine ornamentation of pollen grains were suggested to be important characters in the taxonomy of Parthenocissus, especially for species with trifoliolate leaves. Finally, the previous classifications of Parthenocissus were evaluated within the phylogenetic framework. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, ?? , ??–??.     

Larva and pupa of Cyphopisthes descarpentriesi Paulian (Coleoptera: Scarabaeoidea: Ceratocanthidae) and their phylogenetic implications

Abstract Pupae and mature larvae of the Australian ceratocanthid beetle, Cyphopisthes descarpentriesi Paulian 1977, are described and extensively illustrated. This is the sixth species of the family for which immature stages are known and the first from the Australian region. Unlike other ceratocanthid larvae described before, those of Cyphopisthes Gestro lack stridulatory teeth on the middle and hind legs and any trace of a frontoclypeal suture on the cranium. Reduced one-segmented labial palpi in Cyphopisthes are unique in Scarabaeoidea. Monophyly of the family is not corroborated by larval characters. Absence of spiracular closing apparatus in larvae is reported in the family for the first time. Like pupae of Ceratocanthus White and Germarostes Paulian, those of Cyphopisthes have thoracic projections, but their shape and location are different. Spiracles are found on abdominal segments 2−4 of pupa; that on segment 2 differs in colour and location from the others.