On the evolution of adult head structures and the phylogeny of Hydraenidae (Coleoptera, Staphyliniformia)

External and internal head structures of adults of Orchymontiinae, Prosthetopinae, Hydraeninae and Ochthebiinae were studied and those of Ochthebius semisericeus and Limnebius truncatellus are described in detail. The results are evaluated with respect to their relevance for a reconstruction of hydraenid phylogeny and also compared with structural features found in adults of other staphyliniform families. The monophyly of Hydraenidae is supported by the presence of a plate‐like, trilobed premento‐hypopharyngeal extension, an unusual origin of m. tentoriohypopharyngalis, dorsal tentorial arms firmly fused with the head capsule, modified basal antennomeres, and palpigers connected by a transverse sclerotized bar. Orchymontiinae are monophyletic and the basal sister group of the remaining Hydraenidae. The presence of a ventral transverse genal bulge and of a pubescent antennal club with more than two antennomeres (reversal in some prosthetopines: e.g. Mesoceration abstrictum) are possible apomorphies of Hydraenidae excluding Orchymontiinae. Prosthetopinae are probably monophyletic and the sister group of Ochthebiinae + Hydraeninae. The latter clade is characterized by a distinct cupula formed by antennomere VI, a loose five‐segmented pubescent antennal club, and a modified antennal musculature. The presence of an unusual tentorio‐pharyngeal dilator is a shared derived feature of Ochthebiinae and the genus Davidraena. The monophyly of Ochthebiinae was confirmed and Ochtheosus is the sister group of the remaining ochthebiine genera, which are characterized by a perforated wall‐like structure formed by the posterior tentorial arms. The absence of this tentorial modification and the fimbriate galea are plesiomorphies retained in Ochtheosus. Calobius differs strongly from other subgenera of Ochthebius and a generic status may be appropriate. The monophyly of Hydraeninae is not supported. Hydraena was confirmed as a clade and Laeliaena and Limnebius are sister groups. The latter genus is characterized by several autapomorphies. The basal position of Orchymontiinae and Prosthetopinae suggests a Gondwanan origin of Hydraenidae and a primary preference for life in running water. Important evolutionary changes of head structures are complex transformations of the antennae and related structures. Yet, the use of the antennae as accessory breathing organs is not a groundplan feature of the family. The results of this study strengthen the case of staphylinoid affinities of Hydraenidae.     

Phylogenetic analysis of Staphyliniformia (Coleoptera) based on characters of larvae and adults

Abstract. One hundred and twenty-one morphological characters of larvae and adults of the series Staphyliniformia were scored (multistate coding) and analysed to determine the family group relationships of the polyphagan groups Scarabaeoidea, Histeroidea, Hydrophiloidea and Staphylinoidea. Cladograms were rooted with exemplars of Adephaga, Archostemata, Myxophaga and the polyphagan families Dascillidae, Derodontidae, Eucinetidae and Scirtidae. Analyses of the same dataset with multistate characters re-coded as presence/absence (144 characters) produced cladograms that were similar to those produced from analyses of the original characters. Cladograms produced from partitioned larval and adult characters differed strongly, with adult-only trees more similar to those produced by combined data. The results confirm the monophyly of Hydrophiloidea + Histeroidea and of Staphylinoidea (including Hydraenidae). The Epimetopidae + Georissidae are the only strongly supported clade within Hydrophiloidea. A clade comprising Hydrochidae, Spercheidae and Hydrophilidae, and a sister-group relationship between the latter two families were confirmed in analyses of the data with presence/absence coding. Helophoridae, Epimetopidae and Georissidae are probably not a monophyletic unit, and additional evidence is needed for a reliable placement of Helophoridae. Scarabaeoidea are placed as a sister taxon of Hydrophiloidea + Histeroidea, but support for this relationship is weak. The branching pattern ((Hydraenidae + Ptiliidae) + (Leiodidae + Agyrtidae)), and a clade comprising Scydmaenidae, Silphidae and Staphylinidae (= ‘staphylinid group’) are well founded. The branching pattern (Orchymontiinae + (Prosthetopinae + (Ochthebiinae + Hydraeninae))) within Hydraenidae is confirmed. Poor resolution at the base of the trees and the placement of some nonstaphyliniform taxa (Dascillidae, Derodontidae, Scirtidae and Eucinetidae) as a sister group to a clade comprising Scarabaeoidea, Hydrophiloidea and Histeroidea suggests that Staphyliniformia may be paraphyletic. It is recommended that series names are eliminated from the classification of Polyphaga, at least for the more ‘primitive’ groups.     

Study of the larva of Nosodendron fasciculare (Olivier 1790) (Coleoptera: Nosodendridae) with implications for the phylogeny of Bostrichiformia

Internal and external features of larvae of Nosodendron fasciculare were examined and compared to character states found in other groups of Derodontoidea and Bostrichoidea. Synapomorphic larval features indicate a sistergroup relationship between Nosodendridae and Derodontidae: tubercular surface structure, body compressed dorsoventrally, tergites with lateral projections, spiracles located on tubular processus. These families share three derived character states with Jacobsoniidae in one of two equally parsimonious trees. However, the monophyletic origin of Nosodendridae + Derodontidae + Jacobsoniidae is not sufficiently established at present. The monophyly of Bostrichoidea (Dermestidae + Bostrichidae + Anobiidae + Ptinidae) is suggested by hypognathism. Larvae of these families are characterized by the absence of the mandibular mola and a robust apical part of the mandible. The monophyly of Bostrichidae + Anobiidae + Ptinidae is indicated by a C-shaped, grub like body and the abdominal apex formed by an enlarged and rounded segment IX. Bostrychiformia are probably paraphyletic. A closer relationship between Bostrichoidea with Cucujiformia is suggested by the possession of cryptonephric malpighian tubules in adults. The specific type of cryptonephridism in Bostrichoidea is probably derived from this condition and is considered autapomorphic. The monophyly of Nosodendridae ( Nosodendron ) is supported by several autapomorphies. The assignment of the supposed larva of Nosodendron ovatum remains unclear. An inclusion of the dermestid genus Orphilus in Nosodendridae is rejected. Muscular features of larvae of Nosodendron (and Derodontus ) are largely plesiomorphic.     

Anatomy of the smallest coleoptera, featherwing beetles of the tribe nanosellini (Coleoptera, Ptiliidae), and limits of insect miniaturization

The internal structure of Nanosella sp., Primorskella sp., and Porophila sp. was described from serial sections and total preparations using light and transmission electron microscopy. The most important structural features related to miniaturization are the absence of midgut muscles, abortion of two Malpighian tubes, a decrease in the number of abdominal spiracles, strong reduction of the tracheal system, the absence of the heart, reduction of the circulatory system and its substitution by the fat body, strong oligomerization and concentration of the nervous system, a decrease in the size and number of neurons, and reduction of the left testis and left ovary. The internal structure of featherwing beetles was analyzed for the first time using 3D computer models, which allowed us to demonstrate changes in the relative volume of organs accompanying the body diminution. The excretory and digestive systems change isometrically, while others change allometrically. The relative volume of the musculature decreases, and that of the nervous and reproductive systems increases. The skeleton mass also increases. The possible factors limiting further diminution in Ptiliidae (egg size, the volume of the reproductive and nervous systems, and the skeleton mass) are discussed.     

Interrelationships of Staphyliniform groups inferred from 18S and 28S rDNA sequences, with special emphasis on Hydrophiloidea (Coleoptera, Staphyliniformia)

The series Staphyliniformia is one of the mega‐diverse groups of Coleoptera, but the relationships among the main families are still poorly understood. In this paper we address the interrelationships of staphyliniform groups, with special emphasis on Hydrophiloidea and Hydraenidae, based on partial sequences of the ribosomal genes 18S rDNA and 28S rDNA. Sequence data were analysed with parsimony and Bayesian posterior probabilities, in an attempt to overcome the likely effect of some branches longer than the 95% cumulative probability of the estimated normal distribution of the path lengths of the species. The inter‐family relationships in the trees obtained with both methods were in general poorly supported, although most of the results based on the sequence data are in good agreement with morphological studies. In none of our analyses a close relationship between Hydraenidae and Hydrophiloidea was supported, contrary to the traditional view but in agreement with recent morphological investigations. Hydraenidae form a clade with Ptiliidae and Scydmaenidae in the tree obtained with Bayesian probabilities, but are placed as basal group of Staphyliniformia (with Silphidae as subordinate group) in the parsimony tree. Based on the analysed data with a limited set of outgroups Scarabaeoidea are nested within Staphyliniformia. However, this needs further support. Hydrophiloidea s.str., Sphaeridiinae, Histeroidea (Histeridae + Sphaeritidae), and all staphylinoid families included are confirmed as monophyletic, with the exception of Hydraenidae in the parsimony tree. Spercheidae are not a basal group within Hydrophiloidea, as has been previously suggested, but included in a polytomy with other Hydrophilidae in the Bayesian analyses, or its sistergroup (with the inclusion of Epimetopidae) in the parsimony tree. Helophorus is placed at the base of Hydrophiloidea in the parsimony tree. The monophyly of Hydrophiloidea s.l. (including the histeroid families) and Staphylinoidea could not be confirmed by the analysed data. Some results, such as a placement of Silphidae as subordinate group of Hydraenidae (parsimony tree), or a sistergroup relationship between Ptiliidae and Scydmaenidae, appear unlikely from a morphological point of view.     

Spiracle structure in scolopendromorph centipedes (Chilopoda: Scolopendromorpha) and its contribution to phylogenetics

The spiracles of scolopendromorph centipedes have long been a source of systematic characters based on their segmental distribution and gross morphology, but microscopic investigations to date have documented only a small number of species. A scanning electron microscopic survey of 34 species that samples the major groups of Scolopendromorpha reveals variability in such features as the structure of the peritremal margin, specific kinds of sensilla and glandular pores on the peritrema, projections on the valves that subdivide the atrium (in Scolopendrinae), and the form of the trichomes around the tracheal openings. Adding new characters from the spiracles to recent morphological datasets for phylogenetic inference reinforces the monophyly of major groups of Scolopendridae and is particularly informative for relationships within Scolopendrini. A bowl-like atrium with the tracheae opening between humps in its floor is more widespread in Scolopendromorpha than previously reported. Shared presence of spiracle muscles in Cryptopidae and Scolopendrinae may reflect convergent evolution of a subatrial cavity in these groups rather than being an apomorphic character for Scolopendromorpha as a whole.     

Morphology of the second- and third-instar larvae of Dermatobia hominis by scanning electron microscopy

Larvae of Dermatobia hominis 10–27 days old were collected from experimentally infected rats and their morphology was studied by scanning electron microscopy. The moult from the second to third instar occurs at 18 days, with emergence from the host at 30 days post-infection. The second-instar larvae bear on the pseudocephalon, antennae (coeloconic sensilla), and coeloconic and basicoconic sensilla on the maxillary sensory complex. The thoracic segments bear small backwardly-directed spines anteriorly and ventral trichoid and campaniform sensilla. The first four abdominal segments have small and large backwardly-directed spines that are absent on segments five and six. The seventh and eighth abdominal segments have medium-sized forwardly-directed spines. Abdominal segments are encircled by campaniform sensilla. The terminal end of the eighth abdominal segment bears the anus, prominent anal lobes and two spiracular openings on each spiracular plate. Spiracular plates show a radial sun ray pattern. The rear abdomen also bears an ecdysal aperture, several pores and eight coeloconic sensilla. Although there are slight morphological differences, the spines (predominantly flat and thorn-like) and sensilla (campaniform and coeloconic) of the third-instar larvae show a similar arrangement to that of second-instar larvae. Thoracic trichoid sensilla are not seen in third-instar larvae. A perispiracular gland aperture is situated above each posterior spiracular opening. These morphological features are compared with those of other cuterebrid larvae.     

Morphological aspects of the third instar larva of Haematobia irritans

The main morphological features of the cephalic region of the larva of Haematobia irritans (L.) are the oral grooves, tripartite labium and the antennomaxillary protuberances that have the dorsal, terminal and ventral sensory organs. The total number of sensilla that are found on the terminal organ differs from other cyclorrhaphous-fly larvae. The fan-shaped anterior spiracles usually consist of seven bulbous digits that are unequal in length. The creeping welts consist of notched, convex plates that split into two separate plates as they approach the midline of the venter. This characteristic has not been described previously for this species or other, higher, dipterous larvae. There are two posterior spiracles with an ecdysial scar, four fan-shaped and branching spiracular hairs and irregularly-shaped spiracular openings. The longitudinal anal opening is situated in the cuticular band that is known as the anal organ.     

On the Head Morphology and Systematic Position of Helophorus (Coleoptera: Hydrophiloidea: Helophoridae)

External and internal features of the head of adults of Helophorus spp. were examined and described in detail. The 6 species under consideration show very little morphological variation. The only distinctive characters, which characterise groups of species, are the presence or absence of the mandibular retinaculum and the symmetric or asymmetric shape of the ultimate maxillary palpomere. Helophoridae is supported by several autapomorphies, e.g. a group of long hairs on the posterodorsal margin of galeomere II and the distinctly serrate hind margin of the right mola. Characters with a potential phylogenetic relevance are listed, presented as a data matrix and analysed cladistically. The monophyly of Hydrophiloidea + Histeroidea, Hydrophiloidea (excl. Hydraenidae), ((Helophoridae + Hydrochidae) + (Georissidae [+ Epimetopidae?])), Hydrophilidae and Sphaeridiinae was supported in all trees. The position of Spercheus remains ambiguous. It is either the sistergroup of the remaining Hydrophiloidea or of Hydrophilidae. Head structures of adults of Helophoridae and Hydrochidae show a remarkable similarity. The following apomorphic character states are shared by both taxa: dorsal side of labrum divided into 2 areas with different surface structure, mentum with 2 longitudinal ridges. A clade comprising these 2 families + Georissidae (and probably Epimetopidae) is supported by the metallic granulation of the dorsal side of the head capsule and a grooved frontoclypeal suture. The presence of tubular mandibular glands may be a derived groundplan feature of Hydrophiloidea + Histeroidea. The proposed interrelationships are partly in contrast to current hypothesis. The hypothesised character evolution may change, if a more extensive set of taxa (e.g. Horelophinae, Horelophopsinae) and characters, especially larval features are used (e.g. stigmatic atrium). Several derived characteristics of the clades listed above may have been secondarily lost in Hydrophilidae.     

Developmental changes in the embryo, pronymph, and first molt of the scorpion Centruroides vittatus (scorpiones: buthidae)

For the first time the scanning electron microscope was used to compare developmental changes in scorpion embryos and the first and second stadia. In the buthid species of this study, Centruroides vittatus, and all other scorpions, the newborn climb up on their mother's back and remain there without feeding for several days. At this location, they undergo their first molt and in a few days they disperse, fully capable of foraging in the terrestrial environment. The results here support earlier suggestions that the first stadium (pronymph) is a continuation and extension of embryological development. The first molt results in a nymph with exoskeletal features much like those in the adult. In the first molt the metasoma becomes relatively longer, and the sting (aculeus) becomes sharp and functional. The metasomal segments are modified for dorsal flexion and sting use. The embryos and the pronymphs have spiracles that open into an invagination near the posterior margin of flap-like abdominal plates in segments 4-7 of the ventral mesosoma. The second instars have spiracles that lead to book lungs farther anterior in sternites. Tubular legs with cylindrical segments in embryos and pronymphs become more sculptured and oval in the transverse plane. Each leg in the pronymph has a blunt, cup-shaped tip while distal claws (ungues, dactyl) are present in the second instar and subsequent stages. There are some sharp bristles and primordial sensilla in the pronymphs, but the second stadium has adult-like surface features: rows of knobs or granulations (carinae), serrations on the inner surfaces of cheliceral and pedipalpal claws, filtering hairs at the mouthparts, peg sensilla on the pectines, and mechano- and chemoreceptor sensilla on the body and appendages. Scorpion embryos and pronymphs have some structures like fossil scorpions thought to have been aquatic. There is a gradual development of features that appear to be terrestrial adaptations. Evidence is provided for the formation of the sternum from third and fourth leg coxal primordia and possibly from the first abdominal segment. This study is the first to provide evidence for a forward shift of the gonopore along with other structures in the anterior abdomen.     

Scanning electron microscopy studies on the first-instar larva of Dermatobia hominis

Abstract. First-instar larvae of Dermatobia hominis collected 1, 4 and 7 days after having penetrated experimentally infected rats, were studied by scanning electron microscope (SEM) observation. On the pseudocephalon there are basiconic and trichoid sensilla (antennal sensory complex), and basiconic, coeloconic and campaniform sensilla (maxillary sensory complex). The thoracic segments bear several rows of small, backwardly pointed, spines, and trichoid, campaniform, coeloconic and pit sensilla. The anterior spiracle is a minute opening. Both small and large spines directed posteriorly are on the first to fourth abdominal segments, which also bear coeloconic and companiform sensilla. These sensilla are present on the unarmed (fifth and sixth) and armed (seventh) abdominal segments. The seventh and the last (eight) abdominal segments have forwardly directed spines. Each spiracular plate has two spiracular openings and four spatulate-like structures called sun rays. The anus and the coeloconic sensilla are proeminent on the last segment. The results are compared with other parasitic dipteran larvae, and emphasize that the multiple types of sensilla on D. hominis larva may have importance in establishing the parasitic phase of the life cycle of this insect.     

The morphology of the larval head of Tipulidae (Diptera, Insecta) - The dipteran groundplan and evolutionary trends

External and internal head structures of the larva of Tipula montium are described in detail. The results are compared to conditions found in other representatives of Tipuloidea and other dipteran and antliophoran lineages. Despite of the conceivably basal position of Tipulomorpha within Diptera, the larvae are mainly characterised by derived features. The partially retracted head, the specific hemicephalic condition and several other derived character states support the monophyly of Tipuloidea. A clade comprising Tipuloidea excluding Pediciidae is suggested by the strongly retracted head, by deep dorsolateral incisions of the head capsule, by a distinctly toothed anterior premental margin, by the loss of the second extrinsic maxillary muscle, and possibly by the loss of the pharyngeal filter. Eriopterinae and Hexatominae are characterised by a tendency towards an extreme reduction of the head capsule. Limoniinae, Cylindrotomidae, and Tipulidae form a clade supported by the presence of a premaxillary suture. This implies the non-monophyly of Limoniidae. A feature shared by Cylindrotomidae and Tipulidae is the presence of a movable lacinia mobilis. However, this is arguably a plesiomorphic feature, as it also occurs in Nannochoristidae. Features of the larval head of Trichoceridae, which were included in Tipulomorpha, do not show affinities with those of Tipuloidea. Trichocerid larvae share a specialised subdivided mandible with larvae of psychodomorph groups. Tipuloidea are a highly specialised group. The characters examined did not reveal plesiomorphic features supporting a basal position, and features suggesting closer affinities with Brachycera are vague. The evolution of dipteran larval head structures was apparently strongly affected by the loss of legs and the tendency to live in cryptic habitats. Diptera are the group of Endopterygota with the highest number of apomorphic features of the larval head. The appendages are generally simplified and the muscular apparatus is strongly reduced. Specialised features evolving within dipteran lineages include specifically arranged brushes of hairs on the labrum and epipharynx, movable messores, subdivided mandibles, different mandibular brushes, and a far-reaching reduction of labial parts.     

Larval head morphology of Hydroscapha natans (Coleoptera, Myxophaga) with reference to miniaturization and the systematic position of Hydroscaphidae

 The head of third instar larvae of Hydroscapha natans was reconstructed three dimensionally on a computer. This technique allowed a detailed examination and presentation of internal features of a representative of the ’suborder’ Myxophaga, which is characterized by the very small size of the immature stages and adults. Larval character states of H. natans were compared with features found in other representatives of the Coleoptera. The monophyly of the Myxophaga (excluding Lepiceridae) is supported by several autapomorphies of the larval head: a broadened, transverse head, scale-like cuticular surface structures, round and flattened labral sensilla, short antennae with only two antennomeres, a ligula with papillae, and a broadened tentorial bridge. A monophylum comprising the Hydroscaphidae and Microsporidae is characterized by a very unusual semientognathous condition of the mouthparts and an unusual shape and large relative size of the brain. The last common ancestor of the Hydroscaphidae, Torridincolidae, and Microsporidae was probably living in hygropetric habitats. Several apomorphies have evolved in correlation with this peculiar life style. The very dense arrangement of muscles and other internal structures, and the unusual shape and size of the cerebrum have resulted from miniaturization. The overall complexity of the head is not reduced in comparison to larvae of other representatives of Coleoptera. A negative allometric relationship between body size and the size of the brain, and a correlation between brain size and the size of neurons was found in several species of Coleoptera examined. Accepted: 16 December 1997     

雷氏黄萤幼虫呼吸系统和呼吸行为

研究雷氏黄萤Luciola leii Fu and Ballantyne幼虫的呼吸系统及其呼吸行为。结果表明:雷氏黄萤幼虫的呼吸系统中只有气管无气囊。前胸、中胸和后胸均分布有气门,无气管鳃,腹部1~8节分布有气门和气管鳃,气门腔基部和气管鳃基部相连,呈"√"状,气管鳃内气管与气门气管相连通。雷氏黄萤幼虫的呼吸行为分为3种:利用胸部气门呼吸、腹部气门呼吸和气管鳃呼吸,其中以腹部气门呼吸为主。     

Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters

A phylogenetic parsimony analysis of fifty-four larval characters of Myxophaga (excluding Lepiceridae) resulted in two minimal length cladograms. The monophyly of Torridincolidae, Hydroscaphidae and Microsporidae is supported by several autapomorphies: miniaturization, flattened body with laterally extended tergites, broadened head, scale-like surface structures, broad tentorial bridge, disc-shaped labral sensilla, spiracular gills and pupation in the last larval exuviae. Hydroscaphidae are the sister group of Microsporidae. Larvae of both families are characterized by semi-entognathous mouthparts, tergites with posterior rows of lancet-shaped setae, claws with flattened basal spines and balloon-shaped spiracular gills. The monophyly of all families is supported by autapomorphies. Torridincolidae excluding Delevea is defined as a monophylum by four derived character states: body ovoid, thorax semicircular and as long as abdomen, labral sensilla fused and abdominal sternite IX distinctly reduced and triangular. The monophyly of Torridincolinae (sensu Endrödy-Younga 1997b) is supported by two autapomorphies. The proposed branching pattern suggests that the early representatives of Myxophaga (excluding Lepiceridae) were living in aquatic conditions with a preference for hygropetric habitats. The tendency to live on rocks in running water and miniaturization have played an important role in myxophagan evolution.     

Extremely miniaturised and highly complex: The thoracic morphology of the first instar larva of Mengenilla chobauti (Insecta,Strepsiptera)

Thoracic structures of the extremely small first instar larva of the strepsipteran species Mengenilla chobauti (ca. 200 μm) were examined, described and reconstructed 3-dimensionally. The focus is on the skeletomuscular system. The characters were compared to conditions found in other insect larvae of very small (Ptiliidae) or large (Dytiscus) size (both Coleoptera) and features of “triungulin” larvae, first instar larvae of Rhipiphoridae, Meloidae (both Coleoptera), and Mantispidae (Neuroptera).The specific lifestyle and the extreme degree of miniaturisation result in numerous thoracic modifications. Many sclerites of the exo- and endoskeleton are reduced. Cervical sclerites, pleural ridges, furcae and spinae are absent. Most of the longitudinal muscles are connected within the thorax, and a pair of ventral longitudinal muscles is present in the pleural region of the meso- and metathorax. This results in a high intersegmental flexibility. Due to the size reduction and the correlated shift of the brain to the thorax, with 94 identified muscles the thoracic musculature appears highly compact. Compared to larger larvae the number of both the individual muscles and the muscle bundles are distinctly reduced. The thorax of the first instar larvae displays many additional strepsipteran autapomorphies. At least partly due to the highly specialised condition, potential synapomorphies with other groups were not found.     

Phylogeny of scolopendromorph centipedes (Chilopoda): morphological analysis featuring characters from the peristomatic area

Alternative schemes for the higher‐level systematics of the centipede order Scolopendromorpha have been established from characters of trunk segmentation, including the segmental position of spiracles, and the presence or absence of eyes. A comparative survey of the preoral chamber by light and scanning electron microscopy contributes 16 new characters of the epipharynx and hypopharynx, sampled from 26 species that represent 20 genera. These new data together with 49 additional morphological characters permit cladistic analysis of the major scolopendromorph groups. The shortest cladograms resolve blind Scolopendromorpha as a basal grade within which a clade now classified as Plutoniuminae + Scolopocryptopidae (supported by unreversed characters from the preoral chamber) is sister to the remaining scolopendromorphs. A unique row of bullet‐shaped sensilla between the labral and clypeal parts of the epipharynx provides a new autapomorphy of the Scolopendromorpha. Either 21 or 23 trunk segments optimize at the base of the Scolopendromorpha but in either case homoplasy is forced on the cladogram. New characters from the epipharynx give additional support for the monophyly of several traditional groupings, including Cryptopinae, Scolopendridae, Otostigmini, and Scolopendrini, and a basal resolution of Asanadini within Scolopendridae. Of the two competing hypotheses for the position of the enigmatic Mediterranean Plutonium zwierleini—being either sister to the cryptopid Theatops or sister to all other Scolopendromorpha—the former hypothesis is strongly supported; spiracles on all trunk segments in Plutonium are homoplastic with the state in Geophilomorpha. Observations on feeding behaviour are needed to illuminate convergence in characters of the epipharynx and mandible in Edentistoma (Otostigminae) and Campylostigmus (Scolopendrini). © The Willi Hennig Society 2008.     

Functional morphology of the feeding apparatus and evolution of proboscis length in metalmark butterflies (Lepidoptera: Riodinidae)

An assessment of the anatomical costs of extremely long proboscid mouthparts can contribute to the understanding of the evolution of form and function in the context of insect feeding behaviour. An integrative analysis of expenses relating to an exceptionally long proboscis in butterflies includes all organs involved in fluid feeding, such as the proboscis plus its musculature, sensilla, and food canal, as well as organs for proboscis movements and the suction pump for fluid uptake. In the present study, we report a morphometric comparison of derived long‐tongued (proboscis approximately twice as long as the body) and short‐tongued Riodinidae (proboscis half as long as the body), which reveals the non‐linear scaling relationships of an extremely long proboscis. We found no elongation of the tip region, low numbers of proboscis sensilla, short sensilla styloconica, and no increase of galeal musculature in relation to galeal volume, but a larger food canal, as well as larger head musculature in relation to the head capsule. The results indicate the relatively low extra expense on the proboscis musculature and sensilla equipment but significant anatomical costs, such as reinforced haemolymph and suction pump musculature, as well as thick cuticular proboscis walls, which are functionally related to feeding performance in species possessing an extremely long proboscis. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 291–304.     

Muscle development in the abdominal region of Larval Hylidae (Amphibia: Anura)

Larval muscle development in the abdominal region of five species of hylid frogs (Scinax nasicum, S. fuscovarium, Hyla andina, Phyllomedusa boliviana, Gastrotheca gracilis) was studied using differential staining techniques. These five species represent three major hylid subfamilies. The development of the main abdominal muscles, the rectus abdominis, the two lateral muscles (obliquus externus and transversus), and the lateral pectoralis abdominalis is described. The number of myotomes of the rectus abdominis varies between five and six, and the abdominal muscles associated with the rectus abdominis (obliquus externus, pectoralis abdominalis, and rectus cervicis) vary interspecifically in time of appearance and configuration. The presence of gaps in the configuration of the rectus abdominis has been related to the lotic habits of the larvae. However, our observations indicate the presence of such gaps in larvae that inhabit lentic environments as well. These results suggest that the presence of these gaps is unrelated to larval habitat. There are relatively small differences in muscle morphology among these closely related species, which apparently cannot be explained by morphological adaptations related to their ecology. In the species studied, the number of elements that form the abdominal musculature in larvae is equal to that observed in adults. Likewise, the general morphology of the muscles is ontogenetically conserved. This suggests that both the axial skeleton and musculature are more ontogenetically conserved in relation to the substantial changes that are observed in the skull and head muscles of developing anurans. J. Morphol. 241:275–282, 1999. © 1999 Wiley‐Liss, Inc.