Genus Macrodiplax Brauer, 1868
Type species: Diplax cora Brauer, 1867
The two species are both tolerant of brackish water and found predominantly in coastal pools. M. balteata occurs from the Caribbean Sea to the Gulf of California, M. cora from the western Pacific to the eastern African coast, but Selysiothemis nigra may be more correctly placed in this genus also. Records in the western Indian Ocean of M. cora are scattered: Oman, Socotra, Somalia, north-eastern South Africa and Mauritius. Probably undiscovered populations exist in Kenya and Mozambique. M. cora is superficially like the equally all-red Urothemis assignata, and may be overlooked elsewhere on the coast. It is medium-sized (hindwing 29-36 mm), with a broader black middorsal line extending along the full length of abdomen, less distinct yellow patch at hindwing base, and shorter and darker pterostigmas. [Adapted from Dijkstra & Clausnitzer 2014]
Male of genus is similar to Urothemis by (a) size, Hw 29-38 mm; (b) arculus in all wings usually closer to Ax1 than Ax2; (c) sectors of arculus in Fw often separate at or just distal to arculus; (d) distal Ax in Fw complete, extends across subcosta like proximal Ax; (e) Fw discoidal field of 2 cell-rows at base; (f) Fw triangle always of 1 cell, subtriangle 1-3; subtriangle of 3 cells [2-3]; (g) 7-8 Ax in Fw [6-9]; (h) at most Hw base with large dark patch; (i) Hw base not so broad, cells evenly proportioned; (j) S4 without transverse ridge, although colour pattern or scar-like seam may indicate its position, there is no ridge of similar magnitude as transverse ridge of S3 and lateral carina of S4. However, differs by (1) Fw discoidal field widens rather than narrows distally, 8-10 cells wide on wing border; (2) Hw base usually with orange rather than dark-brown marking; (3) hamule about as long as genital lobe; (4) Abd red with maturity, with black dorsal line from base to tip. [Adapted from Dijkstra & Clausnitzer 2014; this diagnosis not yet verified by author]
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.
- Dijkstra, K.-D.B, and Clausnitzer, V. (2014). The Dragonflies and Damselflies of Eastern Africa: handbook for all Odonata from Sudan to Zimbabwe. Studies in Afrotropical Zoology, 298, 1-264.
Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2019-03-26].