Anax gladiator Dijkstra & Kipping

Dijkstra, Klaas-Douwe B., Kipping, Jens & Mézière, Nicolas, 2015, Sixty new dragonfly and damselfly species from Africa (Odonata), Odonatologica 44 (4), pp. 447-678 : 539-544

Anax gladiator Dijkstra & Kipping sp. nov. – Swordbearer Emperor (Type Photo 24, Photos 31, 37– 38, Fig. 14)

Taxonomy

Belongs to the genetically, morphologically and ecologically distinct speratus -group of Anax Leach, 1815 (see below). Overlaps geographically with A. speratus Hagen, 1867 that is most similar in coloration, but probably also with A. congoliath Fraser, 1953 that is closer structurally and genetically ( Tree 3) ( Map 6). However, is highly distinct from both, and treated as such by Dijkstra & Clausnitzer (2014). A fourth species in this group has long remained in synonymy with A. speratus but replaces it from the Cape Verde Islands to Nigeria and possibly further east: A. rutherfordi McLachlan, 1883 is distinct genetically ( Tree 3) and has (1) smaller size on average, Hw 49.0– 54.0 mm (n= 5) rather than 52.0–57.0 mm (n = 10); (2) the apices of the mid and hind femora and anterio-exterior side of the front femora black, rather than all femora all red; (3) the apical borders of S 2–6 without lateral black dots; (4) the basal half of the dorsal ridge on S 10 distinctly raised, rather than low and sloping to apex; and (5) the epiproct 60 % as long as the cerci, rather than 50 % ( Fig. 14) [rejected synonymy].

Material studied

Holotype ♂: RMNH.INS.505566 , Congo-Kinshasa, Katanga , Upemba National Park, Kabwekanono, source area of Kafwi , stream through gallery forest and bogs in open grassy plains, 1770 – 1820 m a.s.l. (8.937 ° S 27.166 ° E), 16 -xi- 2011, leg. K.-D.B. Dijkstra, RMNH .

Further material: CONGO-KINSHASA ( Katanga ): 1 ♂ ( RMNH.INS.505567 ), as holotype, RMNH . 1 ♂ ( RMNH.INS.505596 ), Upemba National Park, Munte , river with grassy verges, gallery patches and rapids in miombo woodland, 1450 m a.s.l. (8.77 ° S 26.84 ° E), 18 -xi- 2011, leg. K.-D.B. Dijkstra, RMNH . 3 ♂, Lubumbashi , xi- 1952, leg. C. Seydel, MRAC . 1 ♂, Karavia (Elisabethville) , ix- 1951, leg. C. Seydel, MRAC . ZAMBIA (Northern Province): 1 ♂ ( RMNH.INS.508082 ), Shiwa N’gandu, Kapishya Hot Springs, Mansha River , calm section of clear blackwater river, 1434 m a.s.l.

(11.1702 ° S 31.6053 ° E), 13 -xii- 2014, leg. J. Kipping, RMNH. 1 ♂ ( Photo 37), same locality, 04-xii- 2014, CJKL . 1 ♂, Shiwa N’gandu, Kapishya Hot Springs , small clear stream and pools W of Kapishya, 1456 m a.s.l. (11.1939 ° S 31.5617 ° E), 06-xii- 2014, leg. J. Kipping, CJKL . 1 ♀, Shiwa N’gandu, Kapishya Hot Springs , ovipositing at small sandy and warm (36 ° C) stream flowing off hot springs to the nearby Mansha River , 1434 m a.s.l. (11.1706 ° S 31.6013 ° E), 04-xii- 2014, leg. J. Kipping, CJKL . ZAMBIA (Northwestern Province): 1 ♂ ( RMNH.INS.508081 ), Sakeji River S of Sakeji Mission School, E of Ikelenge , calm section of clear blackwater river, 1385 m a.s.l. (11.2355 ° S 24.3100° E), 25 -xi- 2014, leg. J. Kipping, RMNH . 1 ♂, same locality, same dates, CJKL .

Genetics

Five unique haplotypes (n= 5) nearest to A. congoliath ( Tree 3).

Male morphological diagnosis

Belongs to the speratus -group on account of (a) the unmarked frons; (b)the reddish femora contrasting with the black tibiae; (c) the presence of an accessory lamina on S 10, a small process visible between the cerci in dorsal view; (d) the cerci with broadened and rounded apices; and (e) the epiproct that is at least half as long as the cerci ( Fig. 14). Most recalls the sympatric A.speratus by (f) the entirely orange to red abdomen. However, is (1)small- er on average, Hw 49.0–54.0 mm (n= 12) rather than 52.0–57.0 mm (n = 11); (2) with maturity the frons and thorax remain green, rather than becoming orange to reddish; (3) the apical borders of S 2–6 lack lateral black dots; (4)S 10 has its dorsal ridge raised into a high triangular spike, rather than low and sloping down to apex; and (5) the epiproct is well over half as long as the cerci, rather than about half ( Fig. 14).

Etymology

Latin “sword-bearer” refers to the blade-like spike at the abdomen tip (noun in apposition).

Range and ecology

As with all speratus -group species inhabits streams and small rivers, rather than standing waters as other African Anax . These are nutrient-poor and slightly acidic with peat moss and/or blackwater, and typically open with some gallery or miombo forest nearby ( Photo 38), on sandy plateaus between 1 385 and 1 820 m a.s.l. in Katanga and northern Zambia. Flow can be fast but there are always calm sections, e.g., it was seen in Zambia along a lake below its inflow. Ovipositing females without guarding males were observed on a stream flowing from hot springs and in small pools beside a river. There is an unconfirmed record near the Nyika Plateau of northern Malawi (Allen Barlow pers. comm.) and a possible sighting in suitable habitat near Negage in northern Angola (obs. K.-D.B. Dijkstra) suggesting the species is widespread across the sandy plateaus of southern central Africa.