Trithemis hinnula Dijkstra, Mézière & Kipping, 2015

Dijkstra, Klaas-Douwe B., Kipping, Jens & Mézière, Nicolas, 2015, Sixty new dragonfly and damselfly species from Africa (Odonata), Odonatologica 44 (4), pp. 447-678 : 648-652

Trithemis hinnula Dijkstra, Mézière & Kipping sp. nov. – Mule Dropwing (Type Photo 55, Photos 52, 70– 71, Fig. 32)

Taxonomy

Damm et al. (2010) recovered Porpacithemis trithemoides Fraser, 1958 within their molecular phylogeny of Trithemis Brauer, 1868 . Morphology (see Dijkstra & Clausnitzer 2014) and COI data indicate that the genera/species Congothemis longistyla Fraser, 1953 , Anectothemis apicalis Fraser, 1954 , Porpacithemis dubia Fraser, 1954 and Lokithemis leakeyi Pinhey, 1956 are also related closely to each other and Trithemis osvaldae D’Andrea & Carfì, 1997 ( Tree 9). These genera were recognised for their open venation, but “ Congothemis ” longistyla and “ Porpacithemis ” dubia cannot even be separated using COI, nor can “ Anectothemis ” apicalis and T. osvaldae . “ Lokithemis ” leakeyi is more distinct, but all fall within the variation of Trithemis ( Tree 9). They also share typical generic characters of Trithemis such as the (a) small prothoracic hindlobe; (b) terminally narrowed Fw discoidal field; (c) high anterior lamina; and (d) large and prominently apical hook of the hamule. Furthermore, the female holotype of “ A. ” apicalis agrees in markings and venation with females collected with the male holotype of “ P. ” trithemoides also held in MRAC. All species are best considered as the longistyla -group within Trithemis (see diagnosis below) and we treat the listed genera as junior synonyms of Trithemis and the species T. trithemoides of T. apicalis [new synonymies]. An unnamed taxon with intermediate features but distinct COI sequences occurs with T.apicalis , T. dubia and T. osvaldae in Gabon, which is described here.

Material studied

Holotype ♂. RMNH.INS.508117 , Gabon, Haut-Ogooué Province, Ekala, Boubou stream at road Franceville-Bongoville , forest stream ( Photo 52), 421 m a.s.l. (1.6115 ° S 13.9115 ° E), 27 -i- 2012, leg. J. Kipping, RMNH . Further material. GABON (Haut-Ogooué Province): 1 ♂ ( RMNH.INS.554534 ), Bongoville-Léconi road after Ekala, old village of Boubou, Boubou River , sandy and gravelly (2 m wide, 60 cm deep), open on roadside, bushy near river, 393 m a.s.l. (1.6113 ° S 13.9105 ° E), 09-xii- 2012, leg.

N. Mézière & J. Lekogo, RMNH. 1 ♂ ( RMNH.INS.558877 ), Plateau Batéké, Léconi Valley, Eaux Claires to Camps des Pygmés , clearing near river, 434 m a.s.l. (1.4548 ° S 14.1784 ° E), 26 -x- 2013, leg. N. Mézière, RMNH .

Genetics

Two unique haplotypes (n = 3) form the well-supported sister-group of T.dubia / longistyla and T. apicalis / osvaldae combined ( Tree 9).

Male morphological diagnosis

Typical of the longistyla -group by (a) small size, Hw 26.5–27.5 mm (n = 3); (b) the glossy black dorsum of the frons; (c) Fw discoidal field being partly of 2 cell-rows; and (d) the absence of cell-doublings in the radial planate and thus a single row of cells there. However, (1) the pale thoracic marking are more reduced, i.e., when the mesepimeron and metepimeron still bear distinct pale bands the mesepisternum, as well as the metepisternum between the metastigma and metapleural suture, is unmarked; (2) Hw base has a weakly defined dark patch to about Cux, most like T. apicalis , which is not distinctly darker in the subcostal and cubital spaces as in T. dubia and T.longistyla ; (3) the hamule does not have a slender and sickle-like hook like T. dubia and T. longistyla , but also lacks the distinctly humped lobe of T. apicalis , T. leakeyi and T. osvaldae , instead having a rather short hook and a ridge-like lobe ( Fig. 32); (4) S 4–7 have distinct pale markings ventrally when their dorsum is wholly black, S 5–6 developing some pale grey pruinosity, rather like T. dubia but unlike T. apicalis where pruinosity is more blue and concentrated on the thorax and S 1–3; and (5) the cerci are of normal proportions, with their ventral angle at a third of their length from the apex, rather than a sixth as in T. dubia and T. longistyla ( Fig. 32).

Etymology

Latin “little female mule” refers to the intermediate morphology within the longistyla -group (noun in apposition).

Range and ecology

Swamps in gallery forest at 390 to 440 m a.s.l. on the sandy Batéké Plateau of south-eastern Gabon, where it occurs with T. dubia but is much scarcer. Males were mostly found on bare branches at the forest edge.