title: Tentorial mobility in centipedes (Chilopoda) revisited: 3D reconstruction of the mandibulo-tentorial musculature of Geophilomorpha.
abstract: Mandibular mechanisms in Geophilomorpha are revised based on three-dimensional reconstructions of the mandibulo-tentorial complex and its muscular equipment in Dicellophiluscarniolensis (Placodesmata) and Hydroschendylasubmarina (Adesmata). Tentorial structure compares closely in the two species and homologies can be proposed for the 14/17 muscles that attach to the tentorium. Both species retain homologues of muscles that in other Pleurostigmophora are traditionally thought to cause swinging movements of the tentorium that complement the mobility of the mandibles. Although the original set of tentorial muscles is simplified in Geophilomorpha, the arrangement of the preserved homologues conforms to a system of six degrees of freedom of movement, as in non-geophilomorph Pleurostigmophora. A simplification of the mandibular muscles is confirmed for Geophilomorpha, but our results reject absence of muscles that in other Pleurostigmophora primarily support see-saw movements of the mandibles. In the construction of the tentorium, paralabial sclerites seem to be involved in neither Placodesmata nor Adesmata, and we propose their loss in Geophilomorpha as a whole. Current insights on the tentorial skeleton and its musculature permit two alternative conclusions on their transformation in Geophilomorpha: either tentorial mobility is primarily maintained in both Placodesmata and Adesmata (contrary to Manton's arguments for immobility), or the traditional assumption of the tentorium as being mobile is a misinterpretation for Pleurostigmophora as a whole.
authors.affiliation: Institute of Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Koch
authors.affiliation: Department of Entomology, Biocentre Grindel and Zoological Museum, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schulz
authors.affiliation: Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Edgecombe
keywords: Evolutionary morphology; Myriapoda; head endoskeleton; histology; skeleto-muscular system