Showing papers by "Rolf G. Beutel published in 2007"

Head structures of Karoophasma sp. (Hexapoda, Mantophasmatodea) with phylogenetic implications

Abstract: External and internal head structures of adults of Karoophasma sp. were examined and described. The results are compared with conditions found in other representatives of Mantophasmatodea and members of other lower neopteran groups. The X-shaped apodeme of the frons, the unpigmented oval area enclosed by apical branches of the anterior tentorial arms, the oval sclerotisation at the base of the labrum, the sclerotized rounded apical part of the galea, and the loss of M. labroepipharyngalis are probably autapomorphic for Mantophasmatodea. Plesiomorphic features (groundplan of Neoptera) are the orthognathous condition, the absence of parietal ridges, the absence of a gula, the absence of a ‘perforation of the corpotentorium’, the multisegmented antennae inserted between the compound eyes, the general arrangement of the mouthparts, the shape and composition of the maxillae and labium, and the nearly complete set of muscles. The presence of a transverse muscle connecting the antennal ampullae is a potential synapomorphy of Orthoptera, Phasmatodea and Dictyoptera. Character states suggesting affinities with Grylloblattodea are the absence of ocelli, the elongation of the corpotentorium, and the very similar mandibles with widely separated bases and completely reduced molae. Whether predacious habits are a synapomorphic feature of Mantophasmatodea and Grylloblattodea is uncertain. The retained orthognathous condition in Mantophasmatodea and Mantodea is likely related with different specialized preying techniques in both groups, i.e. rapid forward pushes of the head–prothorax complex, and the use of raptorial legs, respectively. Zusammenfassung Ausere und innere Kopfstrukturen von Imagines von Karoophasma sp. wurden untersucht und beschrieben. Die Ergebnisse wurden mit Befunden bei anderen Vetretern der Mantophasmatodea und bei potentiell nah verwandten Gruppen verglichen. Das x-formige Frontalapodem, die unpigmentierten, von apikalen Auslaufern der vorderen Tentorialarme abgegrenzten ovalen Felder, die ovale Sklerotisation an der Basis des Labrum, der sklerotisierte, abgerundete Apikalteil der Galea und der Verlust von M. labroepipharyngalis sind wahrscheinlich Autapomorphien der Mantophasmatodea. Plesiomorphe Merkmale (Grundplan der Neoptera) sind die Orthognathie, das Fehlen von Parietalleisten, einer Gula und einer ‘Perforation des Corpotentorium’, die zwischen den Komplexaugen inserierenden vielgliedrigen Antennen, die Anordnung der Mundwerkzeuge, die Form und Zusammensetzung der Maxillen und des Labiums, und der nahezu vollstandige Satz von Kopfmuskeln. Das Vorhandensein eines transversalen Muskels, der die Antennenampullen verbindet, ist eine potentielle Synapomorphie der Orthoptera, Phasmatodea und Dictyoptera. Er fehlt bei den Mantophasmatodea. Apomorphe Merkmale, die ein Schwestergruppenverhaltnis mit den Grylloblattodea nahelegen, sind das Fehlen von Ocellen, die Verlangerung des Corpotentorium und die sehr ahnlichen, an der Basis weit voneinander getrennten Mandibeln ohne Mola. Ob die rauberische Lebensweise der Mantophasmatodea und Grylloblattodea eine Synapomorphie darstellt, ist unklar. Die bei den Mantophasmatodea und Mantodea beibehaltene Orthognathie ist wahrscheinlich bei beiden Gruppen mit unterschiedlichen, spezialisierten Jagdtechniken korreliert, mit schnellen Vorstosen des Kopf–Prothorax–Komplexes einerseits, und mit dem Einsatz von spezialisierten Fangbeinen andererseits.

Phylogenetic analysis of Anacaenini (Coleoptera: Hydrophilidae: Hydrophilinae) based on morphological characters of adults

Abstract: The skeletal features of adults of fifty species of Anacaenini (Coleoptera: Hydrophilidae) and six outgroup taxa belonging to Hydrophilini and Laccobiini were examined. Eighty-one characters were selected and analysed cladistically. The resulting trees confirm the sister group relationship of Anacaenini and Laccobiini. Paracymus forms a clade within Laccobiini, as sister group of Oocyclus. Par- anacaena is highly polyphyletic and, like Hebauerina, Grodum and Enigmata deeply nested within a complex formed mainly by Anacaena species (Anacaena complex). The position of Gentilina remains ambiguous, but is also likely to be nested within this group. Notionotus is also part of this clade and clearly is monophyletic. Phelea, Crenitis and Notohydrus are distinctive groups which split off successively at the base of the Anacaena complex. On the basis of our results Enigmata Hansen (syn.n.), Gentilina Hebauer (syn.n.), Grodum Hansen (syn.n.) and Hebauerina Gentili (syn.n.) are synonymized with Anacaena Thomson.

Thoracic morphology of adults of Derodontidae and Nosodendridae and its phylogenetic implications (Coleoptera)

Abstract: External and internal structures of the thorax of six adult representatives of the families Derodontidae and Nosodendridae were examined. A detailed description of the skeleton and musculature is presented for Derodontus maculatus and Nosodendron sp. Phylogenetically relevant characters are discussed and analysed cladistically. A basal origin of Derodontidae within Polyphaga and a sister-group relationship between this suborder and the remaining Coleoptera are not supported. Muscular and skeletal features of Derodontidae are largely consistent with the typical polyphagan pattern and the group is characterized by many specialized features. Previous references to the family as ‘primitive’ are unjustified. The absence of a firm connection between the meso- and metaventrite is a secondary feature, as seen in Scirtoidea and some members of Leiodidae. The contact of the metanepisternum with the mesocoxal cavity is probably also an autapomorphic condition. Two derived muscular features are shared by Derodontidae and Nosodendridae, and several muscle losses are shared by these two families and Scirtoidea and Dascillidae. The monophyly of Derodontidae and a sister-group relationship between Peltastica and the remaining genera are confirmed. Laricobius and Nothoderodontus are probably sister groups. Nosodendron is characterized by several autapomorphic features. Whether the flight musculature is reduced in all members of Nosodendridae is unclear.

Are Polyphaga (Coleoptera) really a basal neopteran lineage – a reply to Kazantsev

Abstract: In a study on the mandible and mandibular articulation of larvae of the lycid genus Platerodrilus Kazantsev proposes a phylogenetic scheme with Polyphaga as a basal group of Neoptera and Lycidae as a basal group within Polyphaga. Here we point out different problems with his interpretation. The taxon sampling was not sufficient. The characters of endopterygote larvae cannot be compared to characters of adults in a phylogenetic context. The neotenic characters of female and adult male Lycidae are not sufficiently taken into account. A phylogenetic hypothesis should be based on multiple character systems and all available data must be considered. Kazantsev based his conclusions on a single isolated character complex. His hypothesis is in deep conflict with a phylogeny based on the molecular data, which clearly show that Lycidae are nested within Elateroidea. The molecular and morphological evidence also implies that females are aberrant neotenic forms and by no means ‘primitive’. Kazantsev's hypothesis is problematic because the presented data are insufficient and the character evaluation is not based on a numerical analysis.