Hidden surface microstructures on Carboniferous insect Brodioptera sinensis (Megasecoptera) enlighten functional morphology and sensorial perception

Abstract

Megasecoptera are insects with haustellate mouthparts and petiolate wings closely related to Palaeodictyoptera and one of the few insect groups that didn’t survive the Permian-Triassic mass extinction. Recent discovery of Brodioptera sinensis in early Pennsylvanian deposits at Xiaheyan in northern China has increased our knowledge of its external morphology using conventional optical stereomicroscopy. Environmental scanning electron microscopy (ESEM) of structures, such as antennae, mouthparts, wing surfaces, external copulatory organs and cerci have shed light on their micromorphology and supposed function. A comparative study has shown an unexpected dense pattern of setae on the wing membrane of B. sinensis. In addition, unlike the results obtained by stereomicroscopy it revealed that the male and female external genitalia clearly differ in their fine structure and setation. Therefore, the present study resulted in a closer examination of the microstructure and function of previously poorly studied parts of the body of Paleozoic insects and a comparison with homologous structures occurring in other Palaeodictyopteroida, Odonatoptera and Ephemerida. This indicates, that the role and presumptive function of these integumental protuberances is likely to have been a sensory one in the coordination of mouthparts and manipulation of stylets, escape from predators, enhancement of aerodynamic properties and copulatory behaviour.

New insights on basivenal sclerites using 3D tools and homology of wing veins in Odonatoptera (Insecta)

“…Such basal organization of the veins CP and ScA distally forming the leading edge of the wing is also known in Namuroningxia elegans Prokop and Ren, 2007 (Palaeodictyoptera: Namuroningxiidae) 28 . The examination of latter species by ESEM uncovered the cuticular microstructures as knob like tubercles on these veins and simultaneously showed also the presence of a vein CA in the leading edge of the wing in this Palaeodictyoptera 29 . This character is also a putative synapomorphy of Odonatoptera with the Palaeodictyoptera, to be searched in the Ephemeroptera and the Neoptera too.…”

Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins

“…Palaeodictyoptera were one of a series of orders in the Palaeodictyopterida, a diverse clade of insects with permanently outstretched wings, except for Diaphanopterodea, which possessed a unique wing flexion. Palaeodictyoptera, along with their relatives within this superorder, possessed piercing-sucking mouthparts that formed a beak, which perhaps allowed them to feed on plant fluids, representing an early dietary specialization among insects [10][11][12]. Palaeodictyoptera had wings with a comparatively simple arrangement of veins, lacking the basal fusions between the principal longitudinal sectors, and corresponding to putative hypotheses of the overall pterygotan ground plan wing form [13].…”

Redefining the extinct orders Miomoptera and Hypoperlida as stem acercarian insects

“…Other interpretations by Kukalová-Peck [ 112 ], Laurentiaux [ 93 ], or even Dohrn [ 113 ], remain more reasonable, describing very long stylet-like mandibles, and long maxillary palps, but without information on other parts such as laciniae. Prokop et al [ 114 ] demonstrated these parts with microstructures by the use of ESEM on Brodioptera sinensis (Megasecoptera) bearing presumably shorter labium that consists of a pair of lobes. Even though these structures are reminiscent of those of Hemiptera (except presence of maxillary palps), they are certainly the result of convergence as already proposed by Laurentiaux [ 64 ] and Emeljanov [ 115 ], and are not synapomorphies with those Acercaria with piercing mouthparts.…”