Orthetrum agaricum Dijkstra, 2015
Western Mushroom Skimmer

Type locality: Grand Gedeh County, Putu Iron Ore Mining concession, Liberia

Diagnosis

Male is nearest to its eastern counterpart O. saegeri by (a) moderate size, Hw 29.5-30.5 mm (n = 7); (b) the absence of cell-doublings in the radial planate and thus a single row of cells there; (c) all subcostal Ax dark; (d) the medium-sized dark brown Pt that are 10-11 % of Hw length, 3.0-3.3 mm; (e) Hw base faintly yellow, but never with a dark brown patch; (f) the slender abdomen, though shorter than Hw; and (g) the hamule excised anteriorly, with expanded hood- or mushroom-like hook that is turned outward, hugging and often partly concealed by the lobe. When not pruinose also similar by (h) the dorsa of S4-6 bearing pairs of pale subapical spots that lie closer to the dorsal than lateral carinae, while the appendages often remain pale. However, (1) the anterior excision at the base of the hood-like hamule hook has a straight rather than sigmoid profile; and (2) the out-turned part of the hamular hook is less than twice as long as wide in ventral view, rather than well over. When not pruinose also (3) only S4-6 have distinct pale subapical spots and S7 is black at most with hint of a spot, while O. saegeri typically has a similar spot there as on S4-6. [Adapted from Dijkstra, Kipping & Mézière 2015]

Habitat description

Mostly standing and often temporary waters, but also streams, in open areas in forest, but sometimes shaded by gallery forest. Often with emergent vegetation, coarse detritus, a soft (like muddy) bottom, and probably blackwater. From 200 to 700 m above sea level.

Distribution

confirmed: Ghana; Liberia

Map citation: Clausnitzer, V., K.-D.B. Dijkstra, R. Koch, J.-P. Boudot, W.R.T. Darwall, J. Kipping, B. Samraoui, M.J. Samways, J.P. Simaika & F. Suhling, 2012. Focus on African Freshwaters: hotspots of dragonfly diversity and conservation concern. Frontiers in Ecology and the Environment 10: 129-134.


Reference

  • Dijkstra, K.-D.B., Mézière, N., and Kipping, J. (2015). Sixty new dragonfly and damselfly species from Africa (Odonata). Odonatologica, 44, 447-678. [PDF file]

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2019-07-23].