Showing papers by "Rolf G. Beutel published in 2009"

Phylogenetic analysis of Elateriformia (Coleoptera: Polyphaga) based on larval characters

Abstract: External and internal structures of larvae of Elateriformia were studied and interpreted phylogenetically. Detailed descriptions of the head of representatives of the superfamilies Dryopoidea (Lanternarius sp.; Heteroceridae), Elateroidea (Melanotus sp.; Elateridae), and Cantharoidea (Phosphaena sp.; Lampyridae) are presented. Internal structures of larvae of Eulichadidae, Callirhipidae, Psephenidae, Dryopidae, Limnichidae, Artematopidae, Drilidae, and Homalisidae were examined for the first time. Loss of the mandibular mola is a common derived feature of Elateriformia. Prognathism, the presence of a broad, sclerotized gula, and an abdominal apex which is formed by tergite IX are considered as synapomorphies of Dryopoidea + Elateroidea + Cantharoidea. The presence of a characteristic maxillolabial complex and vertically arranged extrinsic maxillary muscles strongly support a monophylum comprising Dryopoidea (excluding Eulichadidae and Ptilodactylidae partim), Elateroidea, and Cantharoidea. As currently defined, Ptilodactylidae are paraphyletic. A monophylum comprising Eulichadidae and Ptilodactylidae (excluding Araeopidius and Cladotominae) is supported by the presence of a rigid, articulated mandibular process and paired lobes of segment X, which border the anus laterally. The monophyly of Elateroidea, Cantharoidea, and Dryopoidea (excluding Callirhipidae, Eulichadidae, and Ptilodactylidae part.) is suggested by apomorphic features of the tentorium and by the origin of the vertical maxillary muscles from the strongly modified posterior tentorial arm. The monophyly of Dryopoidea (excluding Callirhipidae, Eulichadidae, and Ptilodactylidae part.) remains open to question. A sister-group relationship between the dryopoid families Limnichidae and Heteroceridae is indicated by a specialized vestiture of setae, a hyaline antennal appendage, and a sclerotized, cranial tentorial connecting bar. The monophyly of Araeopidius, Cladotominae, Chelonariidae, Psephenidae, Dryopidae, Lutrochidae, and Elmidae is suggested by the presence of a ventrally hinged operculum of segment IX. The presence of plumose setae on the mouthparts is a possible synapomorphy of Chelonariidae, Psephenidae, Lutrochidae, and Elmidae. The presence of three retractable anal gills is considered as a significant synapomorphy of the latter three families. The monophyly of Elateroidea + Cantharoidea is indicated by partial reduction and immobilization of the labrum, loss of labral muscles (Brachypsectra?), the presence of a strongly developed M. tentoriohypopharyngalis lateralis, and the presence of a setose pre-oral filter (groundplan). Complete fusion of clypeus and labrum is considered as a possible synapomorphy of the elateroid families (excluding Artematopidae) on the one hand, and of Cantharoidea (excluding Brachypsectridae) on the other. Highly aberrant, plate-like mandibles with restricted mobility and longitudinal sclerotizations of the prosternum are considered as synapomorphies of Cerophytidae, Throscidae, and Eucnemidae. An unusually small and wedge-shaped head capsule, antennae inserted on conspicuous elevations, and a lightly sclerotized, grub-like body are probably synapomorphies of the latter two families. Strongly sclerotized thoracic and abdominal segments with the pleura largely or completely concealed may point towards a closer relationship between Cebrionidae and the elaterid subgroup Elaterinae. The monophyly of Cantharoidea is suggested by the presence of a longitudinal mandibular groove (groundplan). The direct attachment of the vertical maxillary muscles to the posthypopharynx is probably a synapomorphic feature of Homalisidae, Lycidae, Drilidae, Phengodidae (?), and Lampyridae. The monophyly of Homalisidae, Phengodidae, and Lampyridae is strongly supported by the presence of abdominal luminous organs. Fifty-four equally parsimonious PAUP-generated trees required 37 steps whereas 39 steps were needed in the hand-made cladogram. A monophylum suggested by PAUP, comprising Artematopidae, Cebrionidae, Elateridae, and Cantharoidae is in contrast to the results of the mental phylogenetic analysis. Zusammenfassung Phylogenetische Analyse von larvalen Merkmalen der Elateriformia (Coleoptera: Polyphaga) Ausere und innere Strukturen von Larven der Elateriformia wurden untersucht und phylogenetisch interpretiert. Kopfe von Vertretern der Uberfamilien Dryopoidea (Lanternarius sp., Heteroceridae), Elateroidea (Melanotus sp., Elateridae) und Cantharoidea (Phosphaena sp., Lampyridae) sind detailliert beschrieben. Erstmalig wurden innere Strukturen von Larven der Eulichadidae, Callirhipidae, Psephenidae, Dryopidae, Limnichidae, Artematopidae, Drilidae und Homalisidae untersucht. Verlust der mandibularen Mola ist ein gemeinsames abgeleitetes Merkmal der Elateriformia. Prognathic, das Vorhandensein einer breiten, sklerotisierten Gula und eine vom Tergit IX gebildete Hinterkante des Abdomen werden als Synapomorphien der Dryopoidea + Elateroidea + Cantharoidea gewertet. Das Vorhandensein eines charakteristischen Maxillolabial-Komplexes und senkrecht angeordnete ausere Maxillenmuskeln sind starke Argumente fur ein Monophylum das die Dryopoidea (ohne Eulichadidae und Ptilodactylidae partim), Elate-roidea und Cantharoidea umfast. Die Ptilodactylidae nach dem derzeitigen Verstandnis sind paraphyletisch. Ein Monophylum das die Eulichadidae und Ptilodactylidae (ohne Araeopidius und Cladotominae) umfast kann durch das Vorhandensein cines steifen, mit der Mandibel gelenkig verbundenen Fortsatzes und paarigen, seitlichen Analloben des Segment X begrundet werden. Die Monophylie der Elateroidea, Cantharoidea und Dryopoidea (ohne Callirhipidae, Eulichadidae, und Ptilodactylidae part.) wird durch apomorphe Merkmale des Tentorium gestutzt und durch den Ursprung der vertikalen Maxillenmuskeln von den stark abgewandelten hinteren Tentorialarmen. Die Frage der Monophylie der Dryopoidea (ohne Callirhipidae, Eulichadidae, und Ptilodactylidae part.) bleibt offen. Ein Schwestergruppen-Verhaltnis zwischen den Familien Limnichidae und Heteroceridae (Dryopoidea) wird durch eine spezielle Behaarung der Kopfkapsel, einen durchsichtigen Anhang der Antenne und eine sekundare, craniale Tentorialbrucke nahegelegt. Ein Monophylum, das die Gattung Araeopidius, die Cladotominae, Chelonariidae, Psephenidae, Dryopidae, Lutrochidae und Elmidae umfast, kann durch das Vorhandensein eines ventral aufgehangten Operculum des Segment IX begrundet werden. Gefiederte Setae auf den Mundwerkzeugen sind eine mogliche Synapomorphie der Chelonariidae, Psephenidae, Lutrochidae und Elmidae. Das Vorhandensein von drei ruckziehbaren Analkiemen ist ein gewichtiges abgeleitetes Merkmal der drei letztgenannten Familien. Die Monophylie der Elateroidea + Cantharoidea wird durch die folgenden abgeleiteten Merkmale gestutzt: teilweise Reduktion und Immobilisierung des Labrum, Verlust der labralen Muskeln (Brachypsectra?), Vorhandensein eines stark entwickelten M. tentoriohypopharyngalis lateralis, Vorhandensein eines praoralen Borstenapparats (Grundmuster). Die vollige Verschmelzung von Clypeus und Labrum ist eine mogliche Synapomorphie der Familien der Elateroidea (ohne Artematopidae) einerseits und der Cantharoidea (ohne Brachypsectridae) andererseits. Sehr ungewohnliche, plattenartige Mandibeln mit eingeschrankter Beweglichkeit und in Langsrichtung verlaufende Sklerotisationen des Prosternum werden als Synapomorphien der Eucnemidae, Cerophytidae und Throscidae interpretiert. Ein ausergewohnlich kleiner, keilformiger Kopf, Antennen die auf auffallenden Erhebungen inserieren und ein sehr schwach sklerotisierter, madenartiger Korper sind gemeinsame abgeleitete Merkmale der zwei letztgenannten Familien. Ein stark sklerotisierter Rumpf mit weitgehend oder vollig verdeckten Pleuren deutet moglicherweise auf eine nahere Verwandtschaft zwischen den Cebrionidae und Elaterinae (Elateridae) hin. Die Monophylie der Cantharoidea wird durch das Vorhandensein einer Langsfurche der Mandibel nahegelegt (Grundmuster). Der direkte Ansatz der vertikalen Maxillenmuskeln am Posthypopharynx ist wahrscheinlich eine Synapomorphie der Homalisidae, Lycidae, Drilidae, Phengodidae (?) und Lampyridae. Fur die Monophylie der Homalisidae, Phengodidae und Lampyridae spricht das Vorhandensein von abdominalen Leuchtorganen. Insgesamt 54 gleich sparsame Computer-Stammbaume (PAUP) benotigen 37 Schritte gegenuber 39 Schritten im traditionell erstellten Cladogramm. Ein Monophylum das die Artematopidae, Cebrionidae, Elateridae und Cantharoidae umfast steht in Widerspruch zu den Resultaten der mentalen Merkmals-Analyse.

On the systematic position of the family Gyrinidae (Coleoptera: Adephaga)

Abstract: Various characters of adult and larval members of Adephaga and Cupedidae were analyzed, and suggest that Gyrinidae are the sister-group of the remaining Adephaga, and are not closely related to the remaining aquatic Adephaga. The aquatic families Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae seem to form a well founded monophyletic unit. The following characters are considered as synapomorphies of Adephaga excluding Gyrinidae: bifurcate condition of the muscle (= M.) tentoriopraementalis inferior, reduction of hypopharynx, strongly developed prosternal process, reduction in size and specialized modification of the ventral sclerite of the mesothorax, strongly developed mesofurcal arms, a high mesopleural ridge, globular mesocoxae restricted to rotatory movements, invaginated sternum VIII (coxostemum), the strongly curved base of the median lobe of the aedeagus, which articulates with the parameres, the rotated position of the aedeagus in repose, fusion of the larval clypeolabrum with the frons and reduction of the larval lacinia. Mesal shifting of M. episterno-coxalis prothoracis, and the fusion of the apical portions of the malpighian tubules of either side are considered as synapomorphies of Adephaga excluding Rhysodidae and Gyrinidae. Lateral reduction of the meta “sternal” transverse ridge and the presence of the subcubital setal binding patch of the hind wing are considered as synapomorphic characters of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. We postulate that the metacoxal fusion occurred independently in gyrmids and the common ancestor of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. Consequently we consider this character state as another synapomorphy of Trachypachidae and Hydradephaga excluding Haliplidae and Gyrinidae. The following characters are considered as synapomorphies of Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae: Loss of tactile setae on the head capsule, metafurcal origin on the intercoxal wall, expansion of the intercoxal wall, elongation of the subcubital setal binding patch, loss of Mm. furca-coxale anterior and posterior, reduction of the larval abdominal segments IX and X, and the shifting of the uropmphi onto the ventral side of segment VIII. Presence of M. tentorio-mandibularis and M. stipitopalpalis intemus are certainly primitive features of adult gyrinids but the distribution of these character states among most members of Adephaga is yet unclear. Chemical defence gland constituents point towards a very isolated position of Gyrinidae. The old age of the group, documented by a larva found in upper Permian deposits, may support the hypothesis of a sister-group relation-ship between Gyrinidae and the remainder of Adephaga.

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

Abstract: 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.

Structure and function of the arolium of Mantophasmatodea (Insecta).

Abstract: All species of the insect order Mantophasmatodea characteristically keep the 5th tarsomere and pretarsus (arolium plus two claws) turned upwards and off the substrate. The unusually large arolium was studied in two species of Mantophasmatodea using bright field light microscopy, reflection microscopy, fluorescence microscopy, TEM, SEM, and Cryo-SEM. It contains an epithelial gland, numerous tracheoles, and nerves. The gland consists of enlarged epithelial cells with large nuclei, mitochondria, RER, golgi complexes, microtubules, and numerous secretion vesicles. Evidence for exocytosis of the vesicles into the gland reservoir between the epithelial gland and the thick cuticle could be observed. Cryo-SEM revealed that the ventral side of the arolium and distal part of its dorsal side are covered with a liquid film. Fluid footprints of arolia of individuals walking on a glass plate also indicate the presence of secretory fluid on the arolium surface. Behavioral experiments using animals with ablated arolia showed that representatives of Mantophasmatodea do not need their arolia to detect and respond to vibratory communication signals nor to catch small to medium-sized prey. Individuals with ablated arolia were not able to move upside down on a smooth glass plate. We conclude that Mantophasmatodea use their arolia for attachment when additional adhesion force is required (e.g. windy conditions, handling large prey, mating). They can bring their arolia in contact with the surface in a very fast reflex (18.0 ± 9.9 ms). The secretory fluid found on the surface is produced by the gland and transported to the outside, presumably through small pore channels, to enhance adhesion to the substrate. J. Morphol., 2009. © 2009 Wiley-Liss, Inc.

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

Abstract: 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.

Charles Darwin, beetles and phylogenetics

Abstract: Here, we review Charles Darwin’s relation to beetles and developments in coleopteran systematics in the last two centuries. Darwin was an enthusiastic beetle collector. He used beetles to illustrate different evolutionary phenomena in his major works, and astonishingly, an entire sub-chapter is dedicated to beetles in “The Descent of Man”. During his voyage on the Beagle, Darwin was impressed by the high diversity of beetles in the tropics, and he remarked that, to his surprise, the majority of species were small and inconspicuous. However, despite his obvious interest in the group, he did not get involved in beetle taxonomy, and his theoretical work had little immediate impact on beetle classification. The development of taxonomy and classification in the late nineteenth and earlier twentieth century was mainly characterised by the exploration of new character systems (e.g. larval features and wing venation). In the mid-twentieth century, Hennig’s new methodology to group lineages by derived characters revolutionised systematics of Coleoptera and other organisms. As envisioned by Darwin and Ernst Haeckel, the new Hennigian approach enabled systematists to establish classifications truly reflecting evolution. Roy A. Crowson and Howard E. Hinton, who both made tremendous contributions to coleopterology, had an ambivalent attitude towards the Hennigian ideas. The Mickoleit school combined detailed anatomical work with a classical Hennigian character evaluation, with stepwise tree building, comparatively few characters and a priori polarity assessment without explicit use of the outgroup comparison method. The rise of cladistic methods in the 1970s had a strong impact on beetle systematics. Cladistic computer programs facilitated parsimony analyses of large data matrices, mostly morphological characters not requiring detailed anatomical investigations. Molecular studies on beetle phylogeny started in the 1990s with modest taxon sampling and limited DNA data. This has changed dramatically. With very large data sets and high throughput sampling, phylogenetic questions can be addressed without prior knowledge of morphological characters. Nevertheless, molecular studies have not lead to the great breakthrough in beetle systematics—yet. Especially the phylogeny of the extremely species rich suborder Polyphaga remains incompletely resolved. Coordinated efforts of molecular workers and of morphologists using innovative techniques may lead to more profound insights in the near future. The final aim is to develop a well-founded phylogeny, which truly reflects the evolution of this immensely species rich group of organisms.

Phylogenetic analysis of Hydrophiloidea (Coleoptera: Polyphaga) based on molecular data and morphological characters of adults and immature stages

Abstract: An extensive combined data set comprising 160 morphological characters of adults and immature stages of Hydrophiloidea and sequences of six different genes were analysed using parsimony and a Bayesian approach. Analyses were carried out with equal weight for individual morphological and molecular characters, and alternatively with approximately equivalent weight for the entire partitions, i.e., 147 informative morphological characters × 9.5 ≈ 1383 informative molecular characters. With the former approach some conventional groups such as the histeroid lineage (Histeridae and Sphaeritidae), Helophorinae and Sphaeridiinae were recovered. However, the branching pattern as a whole is strongly in contrast to the results of previous studies. The results obtained with the modified weighting scheme (9.5:1) conform more to morphology based analyses. The monophyly of Hydrophiloidea, Histeridae + Sphaeritidae, Epimetopinae + Georissinae, Helophorinae, Sphaeridiinae and of the hydrophiline-sphaeridiine lineage is supported in the parsimony analysis. Spercheinae is placed as sister group of all the remaining hydrophiloid groups and a clade is formed by the subfamilies Epimetopinae, Georissinae, Hydrochinae and Helophorinae. In the Bayesian analysis the monophyly of Hydrophilidae is supported. Georissinae form a clade with Hydrochinae, and Epimetopinae are placed as sister group of a clade comprising Spercheinae + the hydrophiline-sphaeridiine lineage. Berosus is placed as the sister group of the remaining groups of Hydrophilinae-Sphaeridiinae in both analyses, and Sphaeridiinae are always nested within a paraphyletic Hydrophilinae. The divergent results of the different analyses show that important questions in the phylogeny of Hydrophiloidea such as for instance the placement of Spercheinae are still open.