Hemicordulia africana, Dijkstra, Klaas-Douwe B., 2007

Dijkstra, Klaas-Douwe B., 2007, Gone with the wind: westward dispersal across the Indian Ocean and island speciation in Hemicordulia dragonflies (Odonata: Corduliidae), Zootaxa 1438, pp. 27-48 : 38-40

Hemicordulia africana n. sp.

Figs 1 , 6, 11 , 17 .

Hemicordulia similis nec ( Rambur, 1842) – Martin (1906 in litt.).

Hemicordulia asiatica nec ( Selys, 1878) – Pinhey (1961: 105).

Hemicordulia africana n. sp. Holotype ♂ and paratype Ψ with labels: printed “Van Someren, Katera Forest. Masaka Uganda, Oct.-Nov.1953 ” and printed “V.G.L. van Someren Collection. Brit. Mus. 1959-468.” (BMNH) [examined].

Further material: MALAWI: 1 ď, Nkhata Bay, Mkuwazi Forest, 6.v.1966, E. Pinhey ( NMBZ). – MOZAM- BIQUE: 1 Ψ, blue, handwritten “Delagoa B. [= Maputo]”, printed and handwritten by Martin “Collection Selys, Hemicordulia similis Rb., Révision Martin 1906 Hemicordulia similis Rb. [but not listed by Martin (1907).]” ( ISNB). – SOUTH AFRICA (KwaZulu-Natal): 1 ď, Lake St Lucia, pools near small river, Barringtonia trees, 24.xi.1995, G. Carchini; 1 Ψ, Sodwana, small forest stream, 20.x.1996, G. Whiteley & J. Bannatyne; 1 Ψ, Sodwana, stream in Barringtonia forest, 21.xi.1996, G. Whiteley; 1 Ψ (perching high up on twig among trees, 100 m from water), Sodwana, near Lake Ngoboseleni, 9.ii.1997, M.J. Samways; 1 ď (hawking up and down roadside in forest), Cape Vidal, 10.ii.1997, M.J. Samways; 4 ď (hawking among trees and open bush next to forest), 1 Ψ (perching in shade, forest edge), Kosi Bay (26°57’S 32°49’E), among trees and bush, 45 m a.s.l., 16.xii.2000, M.J. Samways ( SUEC). – TANZANIA: 1 ď, Sibweza, 35 mi., Mpanda-Karema Rd., 1050 m a.s.l., 5.xi.1966, J. Kielland ( RMNH). – UGANDA: 1 ď (label states: “ Hemicordulia asiatica Selys F.C. Fraser det. 1953), Entebbe, 17.v.1952, E.C.G. Pinhey ( BMNH); 1 ď, Entebbe, v.1952, E.C.G. Pinhey ( NMKE); 2 ď (label states: “ Hemicordulia ? asiatica or sp.n. det. Miss C. Longfield”), Entebbe, x.1952, E.C.G. Pinhey ( BMNH); 4 ď, Entebbe, x.1952, E.C.G. Pinhey ( NMKE); 6 ď, 2 Ψ, Katera Forest, Masaka, x–xi.1953, V.G.L. van Someren ( BMNH); 7 ď, 1 Ψ, Katera, xi.1953, T.H.E. Jackson ( NMKE); 1 ď, Zika, 28.iii.1962, P.S. Corbet ( BMNH); 1 Ψ, Lake Nabugabo, 4.v.1999, V. Clausnitzer (Coll. V. Clausnitzer); 1 ď, 1 Ψ, Kibale National Park, Kanyawara, Makerere University Biological Field Station (0°35’N 30°20’E), open area, 1500 m a.s.l., 8–30.v.2001, R.H.A. van Grunsven ( RMNH); 1 ď, Semliki Game Reserve, 16.i.2002, C. Williams ( ZMMU).

Diagnosis. Smallest species, with very extensively yellow wing bases in females (see H. similis ).

Description. Holotype male. Measurements (mm): entire length: 44.5, abdomen length (without appendages): 29.5, Fw length: 29, Hw length: 28, Fw Pt: 1.7. Labium pale beige. Mandibles, genae, labrum, clypeus and broad area on lower frons pale brownish yellow. Dorsum of frons metallic green-blue, contrasting weakly with visible yellow on antefrons in dorsal view; vertex with weaker metallic lustre. Occipital triangle and occiput brown; occiput with paired rounded swellings. Postgenae and antennae black. Labrum, clypeus, frons, vertex and occipital triangle with long bristly black hairs. Labium, genae and occiput with finer whitish hairs. Prothorax dark brown. Synthorax metallic green with weakly contrasting large pale brownish yellow areas on anterior half of mesepisternum and centres of mesepimeron, metepisternum and metepimeron resulting in pattern of metallic bands posterior to humeral and metapleural sutures, both of which are narrower than pale areas between them. Mesokatepisternum, metakatepisternum and synthoracic venter pale brownish yellow, with dark transverse band on posterior poststernum. Synthorax covered with dense pale long hairs, especially long on mesepisternum; shorter, darker and denser hairs on antealar sinus. Legs black save for yellow coxae, trochanters, most of fore femora and a hint at base of mid femora. Keels present on anterior face of apical half of fore tibiae and almost whole length of hind tibiae (just falling short of their bases), but absent on middle tibiae. Venation blackish. Wing membrane clear, very narrowly and faintly yellow at extreme bases. Membranule dark brown, slightly paler at extreme base. Pt dark brown. Venation as for genus. 7 Ax in both Fw, 5 in Hw. 5 Px in Fw, 6–7 in Hw. Fw triangles with single cross-veins, Hw triangle uncrossed. Discoidal field of 2 rows of cells at base. Anal loops of 15 cells. Abdomen black with green-purple gloss, marked with weakly contrasting brownish yellow: tergites S1–3 largely pale but darker dorsally (S1–3) and laterally (S3), S4–8 pale laterally and ventrally, from base to apex on S4–6 sides and almost to apex on S7–8; S9–10 all black.

Sternites blackish brown. Cerci and epiproct slender, black ( Fig. 6, 11 ). Cerci with fairly pointed but blunt tips. Secondary genitalia as in Fig. 1 , hamule blackish brown.

Paratype female. Measurements (mm): entire length: 46, abdomen length (without appendages): 32.5, Fw length: 31, Hw length: 30, Fw Pt: 2.0. Larger and paler than holotype. Occiput bears a cluster of short thick brown bristles on each side, besides long pale hairs. Metallic green areas reduced, e.g. broken into two blocks on frons by pale median line, almost no gloss on vertex, and only intense on synthorax behind humeral and metapleural sutures. Fore and mid femora largely pale. All tergites except S9–10 laterally and ventrally yellow. Sternites blackish brown, except on S9–10 paler brown. Basal yellow in wings extensive, to arculus and halfway Ax 1–2 in Fw, and arculus and Ax 2 in Hw. 7 Ax in both Fw, 5 in Hw. 5 Px in Fw, 7 in Hw. Anal loops of 15–17 cells. Vulvar scale appressed, pale brown, extending over almost half of sternite S9, semi-circular with deep cleft ( Fig. 17 ). Cerci black, long and slender, 2.5x longer than S10.

Variation. Substantial. Pale markings are more extensive in females and younger specimens. Thorax and abdomen largely pale when teneral, but may loose pale markings almost completely when mature; typical mature males have restricted narrow lateral streaks on S5–8 or S6–8. The relative length of the vulvar scale and the shape of its cleft is variable, as in all species ( Table 2 ).

H. asiatica H. virens H. atrovirens H. similis H. africana

n (♂: Ψ) 17: 5 11: 6 13: 3 24: 9 33: 10 Etymology. The species is named for its native continent, after having been mistaken for a species named after Asia for about half a century.

Remarks. It is surprising that Fraser (in Pinhey 1961) did not recognise an African species, as the vulvar scale differs clearly from that of true H. asiatica . Pinhey (1985) indicated that his Natal material comprised of “all undersized males”. The species is indeed small, although Pinhey did not explain the background of his remark. The continental taxon is very close to the Madagascan H. similis , but the slight differences appear stable and warrant specific distinction.

Range and ecology. Probably confined to eastern Africa ( Fig. 24 ). The first records are from Entebbe, where also found recently ( Pinhey 1961; Graves 1999). Later found in Malawi and KwaZulu-Natal ( Pinhey 1966; 1985). Interestingly, the single Malawian site is also the only inland African locality for Teinobasis alluaudi and the only Malawian site for Gynacantha immaculifrons , two other suspected trans-oceanic arrivals (Fig. 26). The present records are the first for Mozambique and Tanzania, although Tsuda (2000) did list ‘ H. asiatica ’ for Mozambique, probably because Pinhey (1981) predicted its presence. Lindley (1974) listed H. asiatica for the “high forest” of Côte d’Ivoire without providing details. This anomalous record may pertain to Idomacromia Karsch. H. africana “hawks up and down on the edges of forests or in forest glades, often high in the air” ( Pinhey 1961), but its ecology is otherwise unknown. Adults have been observed from October up to February in South Africa and up to May elsewhere.

Figures

FIGURE 1. Secondary genitalia of Hemicordulia africana n. sp. in lateral view.

FIGURES 2 – 11. 2 – 6, Male appendages of Hemicordulia species in dorsal view. (2) H. asiatica; (3) H. virens; (4) H. atrovirens n. sp.; (5) H. similis; (6) H. africana n. sp.; 7 – 11, Male appendages of Hemicordulia species in lateral view. (7) H. asiatica; (8) H. virens; (9) H. atrovirens n. sp.; (10) H. similis; (11) H. africana n. sp.

FIGURES 12 – 17. Vulvar scale and S 9 of Hemicordulia species in ventral view. (12) H. asiatica; (13) H. virens; (14) H. atrovirens n. sp.; (15) aberrant H. similis (cf. Fraser 1949); (16) typical H. similis; (17) H. africana n. sp.

FIGURES 24 – 25. Geographic (24) and altitudinal (25) distribution of H. africana n. sp. relative to large water bodies. Filled circles are known records (present paper), open circles forested localities near large waterbodies that have recently been intensively surveyed by V. Clausnitzer (pers. comm.), except Mbala by Pinhey (1984). Many sites in the region away from large water bodies have also been researched. A line connects each site to the altitude of the nearest large water body.

Tables

TABLE 2. Comparison of the discussed Hemicordulia species. Figures represent averages for continuous measures and sums, and modi for counts (frequencies given), with ranges given in brackets. The extent of the vulvar scale along S 9 is measured as the distance from the base of the scale to its tip, divided by the distance from its base to the tip of sternite S 9. Relative characters are defined in comparison to H. africana n. sp. and H. asiatica (see Table 1 for details), e. g. the extent of yellow in female wing bases in H. similis is intermediate between the extensive state in H. africana n. sp. and the restricted state in H. asiatica.

Range	India to Myanmar	Mauritius	Réunion	Madagascar; Mahé	eastern Africa
Hw length (♂)	31.0 (30.0–32.5)	34.0 (32.0–36.0)	35.3 (32.5–37.5)	29.2 (27.5–31.5)	28.7 (27.0–30.0)
Hw length (Ψ)	33.2 (31.0–34.5)	36.4 (35.5–37.5)	38.5 (38.0–39.0)	31.3 (30.0–32.5)	29.8 (28.0–32.5)
Fw Ax	7 in 65% (7–8)	8 in 72% (7–9)	8 in 69% (7–9)	7 in 82% (6–8)	7 in 88% (7–9)
Fw Px	6 in 67% (5–6)	7 in 63% (6–8)	7 in 66% (6–9)	5 in 71% (5–6)	5 in 81% (5–6)
Paired dark blotches at base of labrum	absent or vague	absent	vague	distinct	absent
Green on frons	extensive	reduced	extensive	extensive	reduced
Extent of yellow in wing bases (Ψ)	restricted	intermediate	intermediate	restricted to inter- mediate	extensive
Angle of vulvar scale incision (Ψ)	35–55°	20–30°	0–15°	30–50°	10–30°
Extent of vulvar scale along S9 (Ψ)	30–35%	25–35%	25–35%	35–40%	35–45%