Comparative Morphology of the Orthopteran Thorax With a Discussion of Phylogenetically Relevant Characters

Fanny Leubner, Benjamin Wipfler, Sven Bradler (2017): Comparative Morphology of the Orthopteran Thorax With a Discussion of Phylogenetically Relevant Characters. Insect Systematics and Diversity 1 (1): 29-47, DOI: 10.1093/isd/ixx00

New insights into the evolution of the surface antennal sensory equipment in free-living and cave-dwelling beetles (Leiodidae: Leptodirini)

The stable environment of subterranean realms is characterized by constant darkness, temperature and humidity, and scarcity of resources. This led to similar adaptations in different lineages of animals, such as the reduction of eyes and pigmentation. It is common textbook knowledge that blindness in cave insects is compensated for by transformations of other sensorial structures, especially the antennae with their rich array of sensilla. We tested this hypothesis with 33 species of Leiodidae of the tribe Leptodirini (Coleoptera) with and without eyes and from hypogean and epigean environments. We documented and compared the number, types, arrangement and density of smooth and furrowed antennal sensilla on certain flagellomeres. Our statistical analysis that took effects of body size and phylogeny into consideration showed that (1) the number of these sensilla does not differ between hypogean or epigean beetles; (2) the same applies to length and diameter of the antennal sensilla; (3) there is a difference in density, but unexpectedly it is lower in hypogean species. Our finding thus contrasts with widely accepted earlier interpretations for those external antennal sensilla in the studied Leptodirini, showing that sensillar patterns are scarcely affected in these subterranean beetles if at all, and even less dense in blind and cave-living species. Our results thus add a new facet to the evolution of cave animals

Phylogenomics and the evolution of hemipteroid insects.

Hemipteroid insects (Paraneoptera), with over 10% of all known insect diversity, are a major component of terrestrial and aquatic ecosystems. Previous phylogenetic analyses have not consistently resolved the relationships among major hemipteroid lineages. We provide maximum likelihood-based phylogenomic analyses of a taxonomically comprehensive dataset comprising sequences of 2,395 single-copy, protein-coding genes for 193 samples of hemipteroid insects and outgroups. These analyses yield a well-supported phylogeny for hemipteroid insects. Monophyly of each of the three hemipteroid orders (Psocodea, Thysanoptera, and Hemiptera) is strongly supported, as are most relationships among suborders and families. Thysanoptera (thrips) is strongly supported as sister to Hemiptera. However, as in a recent large-scale analysis sampling all insect orders, trees from our data matrices support Psocodea (bark lice and parasitic lice) as the sister group to the holometabolous insects (those with complete metamorphosis). In contrast, four-cluster likelihood mapping of these data does not support this result. A molecular dating analysis using 23 fossil calibration points suggests hemipteroid insects began diversifying before the Carboniferous, over 365 million years ago. We also explore implications for understanding the timing of diversification, the evolution of morphological traits, and the evolution of mitochondrial genome organization. These results provide a phylogenetic framework for future studies of the group

Polyneopteran head morphology and its phylogenetic implications

Polyneoptera beinhaltet zehn traditionelle Insektenordnungen mit so diversen Vertretern wie sozialen Termiten, räuberischen Gottesanbeterinnen oder phytophagen Stab- und Gespenstschrecken. Die Verwandtschaftsverhältnisse zwischen den einzelnen Gruppen sind bisher vollkommen ungeklärt. Die vorliegende Arbeit hatte folgende Ziele: (1) Die Einführung einer neuen Terminologie für die Kopfmuskulatur der Dicondylia, (2) die Weiterentwicklung von morphologischen Techniken, (3) die Diskussion von Taxonomie im phylogenetischen Zusammenhang, (4) die detaillierte Beschreibung der Kopfmorphologie von 23 Polyneoptera sowie 13 Außengruppenvertretern , (5) die Rekon¬struktion der Verwandtschaftsverhältnisse basierend auf den Merkmalen des Kopfes und EST Daten sowie (6) die Erstellung von evolutiven Szenarien für den Kopf der Polyneoptera. Die kladistische Analyse von 149 Kopfmerkmalen unterstützt ein Schwestergruppenverhältnis zwischen den Libellen (Odonata) und den Eintagsfliegen (Ephemeroptera) sowie monophyletische Polyneoptera ohne die Bodenläuse (Zoraptera). Innerhalb der Polyneoptera wurde ein Schwestergruppenverhältnis zwischen Stab- und Gespenstschrecken (Phasmatodea) und Tarsenspinnern (Embioptera) sowie zwischen Grillenschaben (Grylloblattodea) und Gladiatoren (Mantophasmatodea) erhärtet. Die als gesichert geltende Monophylie der Springschrecken (Orthoptera) lässt sich nicht durch Kopfmerkmale begründen. Innerhalb der Geflügelten Insekten lässt sich ein deutlicher evolutiver Trend zur Vereinfachung der Kopfmuskulatur erkennen. Dieser findet innerhalb den Holometabolen Insekten mit einem Minimum von nur noch acht Kopfmuskeln seinen Höhepunkt

A new chameleon of the Trioceros affinis species complex (Squamata, Chamaeleonidae) from Ethiopia

A new species of chameleon, Trioceros wolfgangboehmei sp. nov., inhabiting the northern slopes of the Bale Mountains in Ethiopia, is described. It differs from its Ethiopian congeners by a combination of the following features: presence of a prominent dorsal crest with a low number of enlarged conical scales reaching along the anterior half of the tail as a prominent tail crest, a casque raised above the dorsal crest, heterogeneous body scalation, long canthus parietalis, rugose head scalation, high number of flank scales at midbody and unique hemipenial morphology. Based on morphological characteristics, phylogenetic discordances of previous studies and biogeographical patterns, this new species is assigned to the Trioceros affinis (Rüppell, 1845) species complex. An updated comprehensive key to the Trioceros found in Ethiopia is provided

Parallel evolution of novelties: extremely long intromittent organs in the leaf beetle subfamily Criocerinae

Extreme elongation of a part of the intromittent organ, the flagellum, has occurred several times in Criocerinae (Chrysomelidae). These leaf beetles have acquired a specialized pocket to store the flagellum in the abdominal cavity, at the same time allowing a quick control of movements of this structure during copulation. We investigated the morphogenesis of the intromittent organs of species with and without a flagellum to discuss the evolutionary background of parallel evolution of novel structures. We found that the specialized pocket is formed by the invagination of an epidermal layer and a resultant rotation of the primary gonopore. Invagination itself is a well-known phenomenon in morphogenetic processes, which leads us to hypothesize that the novelty is formed by co-opting a previously acquired genetic system. A large open-space is present within the intromittent organ during the entire morphogenesis in species without a flagellum, and the invagination in the species with a flagellum grows in the corresponding area. This means that there are no physical impediments for the growth of a large pocket. In addition the sites of muscular attachments in the species with a flagellum are also different from those without it. The differentiation of muscles is completed immediately before adult emergence, which means the muscles are adjustable during the entire morphogenesis in this group. Simple modifications probably based on a co-option of previously acquired genetic systems, the potential space for adding a new element, and an adjustable factor in morphogenesis of the intromittent organ facilitate the parallel evolution of the extreme elongation

Two new genera and two new species of Mantophasmatodea (Insecta, Polyneoptera) from Namibia

Two new species and two new genera (Pachyphasma, Striatophasma) of Mantophasmatodea are described from Namibia. Pachyphasma brandbergense is endemic to the Brandberg massif; Striatophasma occupies an extensive area south of the region inhabited by Mantophasma. Phylogenetic analyses (see Predel et al. in press) suggest a sistergroup relationship of Striatophasma and the South African Austrophasmatidae