Mesonosa Tihelka, Li, Huang & Cai, 2020

Li, Yan-Da, Tihelka, Erik, Dahan, Loïc, Huang, Di-Ying & Cai, Chen-Yang, 2021, On the Nosodendridae from mid-Cretaceous amber of northern Myanmar (Coleoptera: Nosodendroidea), Zootaxa 5082 (3), pp. 223-244 : 238-239

Genus Mesonosa Tihelka, Li, Huang & Cai, 2020

( Figs 17–19 )

Type species. Mesonosa scandens Tihelka, Li, Huang & Cai, 2021 .

Material examined. Holotype of M. scandens, NIGP 173928.

Remarks. The maxillary and labial palpi of the holotype of M. scandens appears to be enlarged in both the widefield photos and the micro-CT reconstruction by Tihelka et al. (2021b). As noted by Tihelka et al. (2021b), this enlargement is merely an artefact. In the confocal photomicrographs it is clear that the maxillary and labial palpi M. scandens are slender ( Fig. 18B ). The apparent enlargement is caused by gas bubbles enclosing the palpi. The holotype of M. scandens was cited as sex indeterminate in Tihelka et al. (2021b). Our reexamination of the CT data reveals the genitalia inside the body of M. scandens , which are likely to be female ( Fig. 19 ).

Mesonosa is unique within Nosodendridae in having ventrally lobed tarsomeres 2–4 ( Fig. 18G–I ; Tihelka et al., 2021b). Mesonosa additionally differs from other fossil nosodendrids in having a prosternum without antennal grooves (figs 2D, 4C in Tihelka et al., 2021b) and antennomeres in the club very loosely connected ( Fig. 18C ).

Figures

FIGURE 17. General habitus of Mesonosa scandens Tihelka et al., holotype, NIGP173928, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 18. Details of Mesonosa scandens Tihelka et al., holotype, NIGP173928, under confocal microscopy. A, Head, dorsal view. B, Mouthparts, ventral view. C, Antenna, ventral view. D, Prothorax, ventral view. E, Anterolateral depression of metaventrite (arrowhead), ventral view. F, Mid leg. G, H, Fore leg. I, Mesotarsus. Abbreviations: an9–11, antennomeres 9–11; lbp, labial palp; msc, mesocoxa; msf, mesofemur; mst1–5, mesotarsomeres 1–5; mstb, mesotibia; msv, mesoventrite; mtv, metaventrite; mxp, maxillary palp; pc, procoxa; pn, pronotum; ps, prosternum; pt1–5, protarsomeres 1–5. Scale bars: 200 μm.

FIGURE 19. Female genitalia of Mesonosa scandens Tihelka et al., holotype, NIGP173928, serial horizontal virtual sections based on X-ray microtomographic reconstruction. Abbreviations: gc, gonocoxite; gs, gonostylus. Scale bar: 350 μm.