Zygonyx denticulatus Dijkstra & Kipping

Klaas-Douwe B. Dijkstra, Jens Kipping & Nicolas Mézière, 2015, Sixty new dragonfly and dasmelfly species from Africa (Odonata), Odontologica 44, pp. 447-678 : 665-669

Zygonyx denticulatus Dijkstra & Kipping sp. nov. – Pale Cascader (Type Photo 59, Photos 47, 76–77, Fig. 35)

Taxonomy

Morphologically distinct from Z. flavicosta (see Z. annika sp. nov.) and genetically closer to western African specimens of that species than those found within 40 km of it around Upemba National Park, Katanga ( Tree 10). Treated as a distinct species by Dijkstra & Clausnitzer (2014), but the photograph on page 218 shows this species, and not Z. flavicosta ( Map 12).

Material studied

Holotype ♂. RMNH.INS.505335, Congo-Kinshasa, Katanga , Kiubo, Lufira (large, Kiubo Falls) and Luvilombo (small, rocky) rivers, and adjacent flooded areas, gallery forest and degraded miombo woodland, 840–880 m a.s.l. (9.52°S 27.05°E), 05-xi-2011, leg. K.-D.B. Dijkstra, RMNH.

Further material. ANGOLA (Huambo Province):2♂ (RMNH.INS.507908), Keve (Cuvo) River near Alto Hama, 1 415 m a.s.l. (12.2031°S 15.5952°E), 14- -v-2012, leg. J. Kipping, CJKL. 1♂ (RMNH.INS.507907), same locality and date, RMNH. CONGO-KINSHASA ( Katanga ): 6♂ (RMNH.INS.505334, RMNH.INS.505338, RMNH.INS.505357), 1♀ (RMNH.INS.505336), as holotype, RMNH. 2♂ 1♀ (RMNH.INS.505657), Kundelungu National Park, Masansa, small river with some gallery forest and falls in miombo woodland, 1 440–1 480 m a.s.l. (10.532°S 27.978°E), 22-xi-2011, leg. K.-D.B. Dijkstra, RMNH. 1♂, Kundelungu National Park, Lutshipuka, small river with some gallery forest and falls in miombo woodland ( Photo 47), 1 500–1 530 m a.s.l. (10.557°S 27.958°E), 26-xi-2011, leg. K.-D.B. Dijkstra, RMNH. ZAMBIA (Luapula Province): 1♂ (RMNH.INS.508074), 1♂♀, Mumbuluma Falls, 35 km NW of Mansa, large waterfall, 1 195 m a.s.l. (10.9301°S 28.7354°E), 05-iv-2011, leg. J. Kipping, CJKL. 1♂, Ntumbachushi Falls, 21 km SE of Mbereshi, large waterfall of Ngona River ( Photo 77), 1 154 m a.s.l. (9.8537°S 28.9448°E), 07-iv-2011, leg. J. Kipping, RMNH. 2♂, same locality, same dates, BMNH. 5♂ 1♀, same locality, same dates, CJKL. ZAMBIA (Northern Province): 1♂ (RMNH.INS.508071), Shiwa N’gandu, Kapishya Hot Springs, Mansha River, fast flowing rapids, 1 434 m a.s.l. (11.1702°S 31.6053°E), 06-xii-2014, leg. J. Kipping, RMNH. 1♂, same locality, same dates, CJKL. 1♂♀ (♂ RMNH.INS.508072, ♀ RMNH.INS.508073), Chishimba Falls W of Kasama, Kaela Fall, large waterfall, 1 315 m a.s.l. (10.1089°S 30.9167°E), 07- -xii-2014, leg. J. Kipping, RMNH.

Genetics

Nine unique haplotypes (n = 12) nearest to Z. flavicosta from western Africa, but more distant to the sympatric clade of Z. flavicosta ( Tree 10).

Male morphological diagnosis

Belongs to flavicosta -complex by (a) the modest size, Hw 35.0–39.0 mm (n =24); (b) the moderately dense venation, with 10½–12½ Ax in Fw; (c)the largely black hind legs; (d) the pointed and forward-curved apex of the anterior lamina ( Fig. 35); and (e) the pale subapical band on the dor- sum of S7 that stands out against largely dark S5–6. Differs from sympatric Z. flavicosta by (1) the dorsal dark metallic area that does not extend to the anterior side of the frons; (2) the pale brown and not blackish Pt ( Photo76); and (3)the presence of denticles on the apical border of the genital lobe ( Fig. 35). Also, (4) the labrum is often pale brown at least at its base, although it can be wholly black as in Z. flavicosta ; (5) the background colour of the thorax is browner and the pale stripes are often more fragmented and reduced, e.g., the stripe on the metepisternum is typically broken between the metastigma and wing base, or may be reduced to a single spot in that position, while the metepimeron may bear only one to three spots rather than a T-shaped stripe; and (6) the hook of the hamule often seems longer and more strongly curved, about as long as the width of its base, rather than about half ( Fig. 35).

Range and ecology

Fast-flowing sections and waterfalls of large streams and small rivers in gallery forest and open miombo woodland in Katanga , eastern Angola and north-eastern Zambia, recorded between 840 and 1 530 m a.s.l.