Epiophlebia, Calvert, 1903

Blanke, Alexander, Büsse, Sebastian & Machida, Ryuichiro, 2015, Coding characters from different life stages for phylogenetic reconstruction: a case study on dragonfly adults and larvae, including a description of the larval head anatomy of Epiophlebia superstes (Odonata: Epiophlebiidae), Zoological Journal of the Linnean Society 174 (4), pp. 718-732 : 721

OF EPIOPHLEBIA

The prognathous, dorsoventrally flattened head is strongly sclerotized and covered by cuticle knobs ( Fig. 2D ). Setae are absent. The compound eyes are large and globular, and separated dorsally by slightly more than their own width. An occipital bar as encountered in adult Epiophlebia is absent; the occipital ridge is weakly developed. The eyes are located laterally on the head capsule but are oriented forwards, as the occiput covers the entire posterior side of the head ( Fig. 2B and D ). A distinct circumoccular ridge is absent; SR-µCT data equally show no internal thickening of the cuticle around the border of the eyes. An epistomal ridge is also absent. The positions of the three ocelli are barely discernible in the SEM images as distinct fields ( Fig. 2 ). SR-µCT data reveal that nerve tissue for each ocellus is present (Video Clip S5). The coronal and frontal sutures are absent; the vertex area is flat. The post-occiput is a thin semicircle around the occipital foramen, terminating at the posterior tentorial pits. The anteriorly oriented clypeus is divided into a thin anteclypeus that is not covered by cuticle knobs and a postclypeus that is not distinctly separated from the frons. The frons is flat and continuous with the vertex. The gena is formed as an anterior genal process ( Asahina, 1954: plate 55), which is continuous with the ventral part of the occipital area below the eyes ( Fig. 2a ). A suture or ridge clearly separating the anterior genal processes from the occiput could not be detected. A distinct subgena is also not discernible. The anterior tentorial pits originate just ventral to the anterior mandibular articulation.

Figures

Figure 2. Overview of the outer head anatomy of Epiophlebia superstes: A, ventral view with the right part displayed as a three-dimensional reconstruction in order to show the peculiar muscle arrangement of the labial prehensile mask; B, lateral view; C, frontal view; D, dorsal view. Abbreviations: acl, anteclypeus; agp, anterior genal process; antb, antennal base; cl, cleavage line; cr0lb1 + 2, cranial origin of labral muscles 0lb1 and 0lb2; cr0lb5, cranial origin of labral muscle 0lb5; cr0te3, cranial origin of tentorial muscle 0te3; e, eye; fl, flagellum; fr, frons; lbr, labrum; loc, lateral occellus; lp, labial palpus; moc, middle occellus; oc, occiput; ocr, occipital ridge; pcl, postclypeus; pe, pedicellus; prm, prementum; sc, scapus. For muscle references, see text and Table S2. Scale bar: 1 mm.