The enigmatic Mesozoic insect taxon Chresmodidae (Polyneoptera): New palaeobiological and phylogenetic data, with the description of a new species from the Lower Cretaceous of Brazil

Abstract

The morphology of the enigmatic, Mesozoic, aquatic insect family Chresmodidae is redescribed and its phylogenetic affinities among the polyneopterous orders discussed. Study of the complete venation of both fore-and hind wings observed in some specimens from the Spanish Barremian, permit us to postulate the hypothesis that the family belongs to the Archaeorthoptera, thus to the orthopteroid lineage rather than to crown-group Phasmatodea or to the more inclusive group Holophasmatodea (sensu GRIMALDI & ENGEL, 2005). New specimens from Spain, Lebanon, Brazil, and Germany permit a new re-description of some chresmodid body structures with concomitant implications for the phylogenetic position of the family. Chresmoda neotropica n. sp. is described from the Aptian-Albian of the Crato Formation (northeast Brazil). The functional morphology proposed for some of their specialized structures suggest a new hypothesis of Chresmoda palaeobiology, and related to this some implications for the localized palaeoenvironment as well as global palaeoclimate. The problematic Sternarthron spp. from the Upper Jurassic of Solnhofen were described as probable palpigrades (Arachnida: Palpigradi), based on type material originally thought to be fossil insects. The affinities of Sternarthron HAASE, 1890 have been questioned. Our restudy of HAASE's types clearly confirmed earlier assumptions that these fossils represent nymphal specimens of chresmodids. Consequently, Sternarthron has to be considered as an invalid junior synonym of the fossil insect genera Propygolampis WEYENBERGH, 1874 and Chresmoda GERMAR, 1839.

New stem-Phasmatodea from the Middle Jurassic of China

“…The comparatively low extant diversity in this order is mirrored by its rarity in the fossil record: a few tens of species are to varying extents convincingly assigned to this order (Birket-Smith, 1981;Gorochov, 1988Gorochov, , 1992Gorochov, , 1993Gorochov, , 1994Gorochov, , 2000Martynov, 1928;Nel et al, 2004Nel et al, , 2010Ren, 1997;Sharov, 1968Sharov, , 1971Tillyard, 1918;Wedmann et al, 2007;among others). However actual affinities of many fossil taxa remain uncertain (Grimaldi & Engel, 2005;Tilgner, 2000; and see discussion by Gorochov, 2000;Bradler & Buckley, 2011, with respect to Nel et al, 2010and Delclòs et al, 2008).…”

An early winged crown group stick insect from the Early Eocene amber of France (Insecta, Phasmatodea)

“…The tegmina of Gallophasma is complete and its wing venation is well preserved, showing several important characters that remain unknown in the described Archipseudophasmatidae (Zompro, 2001, 2004, 2005), especially specialized structures of the cubito‐median veins, namely basal fusion of convex CuA with R + M into a common stem; separation of M + CuA into a forked convex branch MA and a more neutral but convex posterior branch MP + CuA; concave CuP divided into branches, one of them (CuPa) reaching the posterior branch of M + CuA; convex CuA(+CuPa) separating from weakly concave MP some distance from wing base. Identical structures are found in Mesozoic taxa that were considered as stem group Phasmatodea, namely the marine insect Chresmoda , the Jurassic Orephasma and the Triassic Aeroplana (Delclòs et al, 2008: fig. 6).…”

“…The phylogenetic relationships of the Phasmatodea remain controversial, despite several recent morphological and/or molecular works, with possible relationships with Dermaptera, Embioptera, Grylloblattodea + Dictyoptera, Dictyoptera or Orthoptera [for a summary of the state of the art, see Delclòs et al (2008: 370)].…”

“…It is impossible to decide if this is because of the preservational state of these fossils or because they are truly absent. Delclòs et al (2008) demonstrated that at least some of the pre‐Cenozoic ‘Phasmatodea’ have a pattern of wing venation of the ‘orthopteroid’ type ( Orephasma Ren, 1997; Aeroplana Tillyard, 1918; Chresmoda Germar, 1839), suggesting close affinities of these fossil insects with the clade Archaeorthoptera Béthoux & Nel, 2002. Nevertheless, no certain affinity of these pre‐Cenozoic phasmid‐like insects and the true Euphasmatodea has been demonstrated.…”

Mesozoic giant fleas from northeastern China (Siphonaptera): Taxonomy and implications for palaeodiversity

“…Saurophthirus has recently been considered to be a specialized flea, like Tarwinia [10]. The genus Saurophthiroides was initially considered a relative of Saurophthirus but was subsequently discovered to be a synonym of Chresmoda [11]. However, Strashila is not an ectoparasite at all according to our recent study, including an account of the hitherto unknown female [12].…”