On the head morphology of Grylloblattodea (Insecta) and the systematic position of the order, with a new nomenclature for the head muscles of Dicondylia

Abstract

External and internal head structures of adults of Galloisiana yuasai (Grylloblattodea) are described. The results are compared with conditions found in representatives of other lower neopteran lineages, notably in Austrophasma and Karoophasma (both Mantophasmatodea). Sutures and ridges of the head capsule are discussed. A new nomenclature for head muscles is presented for the entire Dicondylia (= Zygentoma + Pterygota). Galloisiana (like its sister taxon Grylloblatta) is mostly characterized by plesiomorphic features, such as the largely unspecialized orthopteroid mouthparts, the multisegmented filiform antennae, the presence of trabeculae tentorii, the absence of muscles associated with the antennal ampullae, the presence of musculus stipitalis transversalis (0mx11) and the presence of musculus tentoriofrontalis anterior (0te2). Autapomorphies of Grylloblattodea are: (i) compound eyes composed of only 60 ommatidia or less; (ii) a lacinia with a proximal tooth; (iii) a rounded submentum; (iv) loss of musculus craniohypopharyngealis (0hy3); and (v) loss of musculus labroepipharyngealis (0lb5). The phylogenetic evaluation of 104 characters of the head yields a branching pattern with Grylloblattodea as a sister group of Mantophasmatodea in clade Xenonomia. Putative synapomorphies of both taxa are: (i) a distinct angle (more than 60 • ) between the submentum and the mentum; (ii) posteriorly oriented labial palpi; (iii) a flat and lobe-like hypopharynx with a suspensorium far ventrad of the anatomical mouth opening; (iv) loss of musculus tentorioparaglossalis (0la6); and (v) a connection between the antennal ampulla and the supraoesophageal ganglion containing nuclei. Xenonomia is placed in a clade with the two dictyopteran terminals. Another monophyletic group is Embioptera + Phasmatodea. Most branches of the single tree obtained in our analysis are weakly supported. The results clearly show that more data and a much broader taxon sampling are required to clarify the phylogenetic interrelationships of the lower neopteran orders. However, our results narrow down the spectrum of possible solutions, and represent a starting point for future phylogenetic analyses, with an extensive concatenated dataset.

Musculoskeletal modeling of the dragonfly mandible system as an aid to understanding the role of single muscles in an evolutionary context

“…In many 'higher' insects such as certain Grylloblattodea, Mantodea and Orthoptera, a part or all of muscles 0md5-8 are absent (Blanke et al, 2012). We therefore suggest that muscles 0md5-8 do not play a crucial role during biting in winged insects like Ephemeroptera, Odonata and Polyneoptera and accordingly were reduced in some higher lineages of insects [see character matrices in, for example, Blanke et al (2012Blanke et al ( , 2013a and Wipfler et al (2011) for presence/ absence of these muscles within winged insect orders].…”

“…As we follow the terminology of Beutel et al (2013) and Wipfler et al (2011), and to allow for comparison with the literature record, we retained the term 'tendon' here. Because of this sclerotization, the material properties of this structure cannot be compared with tendon-like structures in, for example, vertebrates.…”

“…They possess a suite of six to seven mandibular muscles, thus showing a plesiomorphic muscle equipment with respect to all other winged insects except mayflies (Ephemeroptera), which possess eight (Staniczek, 2000). However, regarding their mandible joints and the configuration of the mandibular teeth (or incisivi), Odonata show the typical ball-and-socket joints and incisivi of many 'higher' insects (Neoptera; Blanke et al, 2012;Staniczek, 2000Staniczek, , 2001Wipfler et al, 2011). In particular, the mandibular system ( joint types, muscles, mandible motion) of Odonata, Ephemeroptera and Neoptera has been intensely studied concerning its phylogenetic value to infer the relationships of these three groups to each other (Staniczek, 2000(Staniczek, , 2001.…”

Review of the Gross Anatomy and Microbiology of the Phasmatodea Digestive Tract

“…Autapomorphies include prothoracic defense glands and small, pyriform appendages on the posterior midgut (tilgner et al 1999(tilgner et al , Beutel et al 2013 recently demonstrated as having a unique excretory function (Shelomi & Kimsey 2014). the sister order to the phasmatodea is most likely embiidina (webspinners) forming a "eukinolabia" clade, based on external morphology (Wipfler et al 2011, Friedemann et al 2012, Beutel et al 2013, rdnA (Flook & Rowell 1998, terry & Whiting 2005, expressed sequence tags (letsch et al 2012) and transcriptomics (Misof et al 2014). Future phylogenetic analyses are still required to resolve the relationships of the polyneopteran orders (trautwein et al 2012): in particular, comparisons of internal features are lacking due to the inconsistent anatomical studies.…”

Evolutionary phenomics and the emerging enlightenment of arthropod systematics

“…The tissue contrast of pure absorption contrast data are, however, very high, and therefore SRmCT might be considered an excellent alternative to histological (Wirkner and Richter 2007) will help surmount these issues. Examples of articles using SRmCT to infer arthropod systematics include Beutel et al (2009a), Friedrich and Beutel (2010), Huckstorf and Wirkner (2011), Talarico et al (2011), Wipfler et al (2011) and Friedemann et al (2012. Researchers have also used SRmCT to explore the characteristics of obscured fossil insects in amber (Tafforeau et al 2006;Lak et al 2008) and to partially reconstruct the internal phenomes of fossil insects (Pohl et al 2010).…”