Tragogomphus grogonfla Dijkstra ^ZBK sp. nov. – Western Horntail (Type Photo 43, Photo 57, Fig. 27)

Taxonomy

Dijkstra (2007) proposed to restrict the genus Tragogomphus Sjöstedt, 1900 to the type species T. aurivillii Sjöstedt, 1900 from Cameroon and the closely similar T. ellioti Legrand, 2002 from Gabon. Populations in the Upper Guinea are genetically distinct from T. ellioti and differ clearly from both species in the male appendages (Fig. 27).

Material studied

Holotype ♂. RMNH.INS.503176, Sierra Leone, Eastern Province, Gola Forest, Sembehun (abandoned village), sandy stream and adjacent spring area in forest, 219–233 m a.s.l. (7.7598 ° N 10.7174 ° W), 11 -iii- 2011, leg. K.-D.B. Dijkstra & A. Dayeker, RMNH .

Further material. LIBERIA (Grand Gedeh County): 1 larva (RMNH.INS.501515), Putu Iron Ore Mining concession, Biodiversity Camp, sandy and gravelly streams and muddy seepage in rainforest, 299 m a.s.l. (5.6592 ° N 8.2041 ° W), 22 -i- 2011, leg. K.-D.B. Dijkstra & A. Dayeker, RMNH . 1 larva (RMNH.INS.501529), Putu Iron Ore Mining concession, Jerry’s Camp, complex of streams, seepages and (goldmining) pools east of camp in rainforest, 283 m a.s.l. (5.6732 ° N 8.2245 ° W), 24 -i- 2011, leg. K.-D.B. Dijkstra & A. Dayeker, RMNH . 1 larva (RMNH.INS.501648), same locality, 19 -ii- - 2011, leg. K.-D.B. Dijkstra & A. Dayeker, RMNH . LIBERIA (Nimba County): 1 ♀ (RMNH.INS.506080), West Nimba Proposed Forest Reserve, Van- yanpa Camp, 3.5 km S of Bentor, small sandy and rocky stream in rainforest, 447 m a.s.l. (7.4922 ° N 8.6998 ° W), 09-iii- 2012, leg. K.-D.B. Dijkstra & M. Darpay, RMNH . 1 ♂ (RMNH.INS.501463), 1 ♀ (RMNH.INS.501462), 2 larvae (RMNH.INS.501474, RMNH.INS.501475), Mt Tokadeh, “ladder falls” on road to old mine, springs, sandy stream and swampy forest (Photo 57), 600–660 m a.s.l. (7.445 ° N 8.658 ° W), 13–14 -i- 2011, leg. K.-D.B. Dijkstra, RMNH . 2 larvae (RMNH.INS.501683, RMNH.INS.501685), same locality, 18–19 -iii- 2011, leg. K.-D.B. Dijkstra, RMNH . 1 ♂ (RMNH.INS.506057), 1 larva (RMNH.INS.506060), Mt Beeton, stream towards summit, small rocky stream in rainforest, 785 m a.s.l. (7.5299 ° N 8.6638 ° W), 06-iii- 2012, leg. K.-D.B. Dijkstra & M. Darpay, RMNH . 1 larva (RMNH.INS.505694), eastern flank Mts Gangra and Yuelliton, lower Yehwah valley, rocky stream in forest, 505–522 m a.s.l. (7.5567 ° N 8.6153 ° W), 04-iii- 2012, leg. K.-D.B. Dijkstra & M. Darpay, RMNH . SIERRA LEONE (Eastern Province): 1 larva (RMNH.INS.503182), as holotype, leg. K.-D.B. Dijkstra & A. Dayeker, RMNH . 1 larva (RMNH.INS.503124), Gola Forest, Gagbe stream, 1 km W of Mogbaima, stream from uppercourse in forest to heavily disturbed area with diamond pits, 136 m a.s.l. (7.6574 ° N 10.7788 ° W), 03-ii- 2011, leg. K.- D.B. Dijkstra & A. Dayeker, RMNH .

Genetics

Seven unique haplotypes (n= 16) nearest to but distinct from T. ellioti from Gabon, although T. aurivillii from Cameroon was not sampled.

Male morphological diagnosis

Similar to T. ellioti and presumably the poorly known T. aurivillii by (a)fairly large size, Hw 31.0–33.0 mm (n = 2); (b) the pale medially narrowed bar across anterior half of the brown labrum; (c) the centrally depressed vertex, without a ridge between the lateral ocelli; (d) the denticles on the occipital ridge; (e) the anterior hamule’s short and curved hook on a low rounded base; (f) the wide-based cerci in lateral view with a sub-basal hump and concave dorsal profile; and (g) the up-curved branches of the epiproct thickened and somewhat recurved subapically (Fig. 27). However, (1) the dark interpleural and metapleural stripes are wider than the green stripes flanking them; (2) the most posterior black stripe on the thorax sides extends across the lower corner of the metepimeron, not dead-ended; (3) the epiproct branches have a marked dorsal angle subapically; and (4) the epiproct’s apices beyond the dorsal angle are short, not reaching beyond the tips of the cerci (Fig. 27).

Etymology

Name alludes to the pronunciation of ‘dragonfly’ by Mr Edward Rose, who assisted the author in Liberia (noun in apposition).

Range and ecology

Sandy and gravelly headwater streams between 150 and 800 m a.s.l. in rainforest in Liberia and adjacent Sierra Leone. The first true Tragogomphus species found outside Cameroon and Gabon.