Iolaus njombe, Sáfián & Bayliss & Congdon, 2022

Sáfián, Szabolcs, Bayliss, Julian & Congdon, T. Colin E., 2022, Description of four IolausHübner, 1819 species in the subgenus PhiliolausStempffer & Bennett, 1958 from East Africa, assigned to the proposed I. maritimus species group (Lepidoptera, Lycaenidae, Theclinae), Zootaxa 5099 (1), pp. 46-64 : 52-54

Iolaus njombe sp. nov. Sáfián

FIGS.: 2G, J; 3G, J; 4D; 5D; 8C, 10

Holotype: ♂ TANZANIA, Njombe, S. Tanzania, 6000 ft. 4.1993. S.C. Collins bred. Gen. prep.: SAFI00367 . ABRI unique number: ABRI-2019-3069. Deposited in ABRI.

Paratypes: 1♂ TANZANIA, Njombe, S. Tanzania, 6000 ft. 4.1993. S.C. Collins bred. Gen. prep.: SAFI00366 , ABRI unique number: ABRI-2019-3068. 1♀ TANZANIA, Milo , III.2013. ABRI MH / PW . Gen. prep.: SAFI00368 . ABRI unique number: ABRI-2019-3070. Deposited in ABRI .

Description of male. Forewing length: 19.3 mm. Wingspan: 35 mm. General appearance as males of other species in the subgenera Argiolaus and Philiolaus with black ground colour overlaid by extensive iridescent blue on upperside, and dirty white underside with black and orange submarginal lines, two tails at the tip of veins 1 and 2 and a small kick at the tip of vein 3 on the hindwing. Upperside blue colour of royal blue tone with no greenish or silverish tinge. Slightly less than basal half of forewing covered with blue, except along costa, where black extends to base, leaving a broad, 2 mm black costal margin. Black outer margin very broad, over 2 mm at tornus. The outer edge of blue area evenly rounded, except in space 3 where edge of blue patch slightly lobed. Majority of hindwing covered with blue, except dark grey-black space 1a, along black costa, and the broad black margin between apex and tornus. Black margin almost evenly broad, 1.5–2 mm with slight blue scaling in spaces 1b, 2 and 3. Androconia cover most of cell and upper part of wing to black costa, dark greasy grey-black with black, well-defined oval heart. Tornal lobe dark claret-red, speckled with few blue scales, with black margin. Underside dirty white, with creamy tinge along forewing costa and very faint grey dusting along forewing and hindwing margin. Forewing with bright, slightly curving orange-red submarginal line between veins 2 and 8. Black, faint, 1 mm-long cell-closing streak also present. Forewing androconial hair tuft beige. On hindwing, prominent, orange-red inner submarginal line keeps strongly away from outer margin, reaching costa 5 mm from apex. Outer submarginal line absent. Tornal spot at the end of space 1a largely black, edged with claret-red and silvery-blue ring inwardly. That in space 2 claret-red, with silvery-blue ring, connected to tornal end of orange submarginal line. Tails black with white edge. Fringes short along outer margin of forewing, black on upperside, longer, grey along inner margin. Fringes black on hindwing outer margin, replaced by longer whitish hairs along inner margin. Fringes grey on forewing underside, white on hindwing. Head, thorax and abdomen black with greyish hairs on upperside, covered by white hairs on thorax underneath, abdomen with yellowish overlay. Palpi black on top, white below, twice as long as diameter of eyes. Eyes bald, black. Antennae black, speckled with tiny white dots underneath, only slightly thickened towards apex, their length shorter than half of forewing.

Male genitalia. General morphology like those of other species in the I. maritimus group as described above. Valvae moderately broad, oblong, ending in short acute tip, the lower edge of tip is rather strongly serrated. Cingulum well developed, tongue-like or triangular, the terminal cornutus on aedeagus strong, straight or curving gently downward, the inner one narrow, with serrated lower edge, curving slightly upwards. Third cornutus short, protruding laterally from tip.

Description of female. Forewing length: 21.2 mm. Wingspan: 39 mm. General appearance as females of other species in the subgenera Argiolaus and Philiolaus with black ground colour overlaid by blue and orange spotting along outer margin on hindwing in spaces 1a, 2 and 3. Underside dirty white with black and/or orange-red submarginal lines and two tails at the tip of veins 1 and 2 and a small kick at the tip of vein 3 on hindwing. Blue colour of light whitish sky-blue tone, slightly darker towards the bases and with a whitish area in the apical corner of the blue patch on forewing. Less than half of forewing covered with blue basally, costa broadly black to base. Outer edge of blue area evenly rounded. Basal half of hindwing covered with blue, between vein 1 and 7, grey between vein 7 and costa, except light blue base. Black submarginal line formed by prominent lunules in spaces 1b, 2, 3 and 4. Tornal lobe claret red, speckled with blue scales, with black margin, not conjoint with fused bright orange spotting in spaces 1b, 2 and 3. Tails black, edged with white. Underside colour and pattern and body identical to those of male.

Female genitalia. Papillae analis small (<1 mm), weakly sclerotized, almost flat. with dense hair, apophyses straight, shorter than 1 mm. Lamella antevaginalis strongly sclerotized, its terminal end bilobed, anteriorly, ending in strongly sclerotized mouth of ductus. Mouth of ductus broad, sclerotized almost all the way to bursa, narrows down strongly before the mouth of bursa. Bursa copulatrix completely membranous, fig shaped.

Variation. The male paratype has a small round claret-red spot in the hindwing black margin in space 1b. Red spotting appears variably in the hindwing subtornal area in various species in the subgenera Argiolaus and Philiolaus .

Differential diagnosis. I. njombe differs from I. maritimus , I. uluguru and I. collinsi with the presence of a small, black cell-closing streak on the forewing underside, present in both sexes ( Figs. 2J ; 6J ). This feature is typical in I. stewarti ( Figs. 2K, L ; 6K, L ). However, the male genitalia of I. njombe differ from that species and the newly described I. bundali with the presence of a well-developed process on the vinculum and the acute tip of valva with strong serration on its lower edge ( Figs. 3G ; 4D ).

Biology and habitat. The biology of I. njombe is unknown, the larval foodplant is almost certainly a species of Loranthaceae in the Taxilloid group. Its habitat is probably montane forest.

Etymology. The species is named after Njombe town in the Kipengere Range in western Tanzania, the type locality of I. njombe .

Discussion. I. njombe is only known from two localities on the Kipengere Range in southwestern Tanzania, east of the northern corner of Lake Malawi. This mountainous area is part of the East African Rift ecosystem (also referred to as Tanzanian Southern Highlands), which is home of numerous endemic butterflies, including at least four described Iolaus species ( Heath 1985, https://programs.wcs.org/portals/49/media/file/Butterflies.pdf). I. njombe could easily prove endemic to the Kipengere Range, or the eastern escarpments of the Lake Malawi Rift, but examination of further material is required to understand its distribution.

Figures

FIGURE 2. Males: I. maritimus usambara (Tanzania, Usambara) upperside—A, underside—D; I. uluguru (holotype) upperside—B, underside—E; I. collinsi (holotype) upperside—C, underside—F; I. njombe (holotype) upperside—G, underside—J; I. stewarti (Malawi, Nyika Plateau) upperside—H, underside—K; I. bundali (holotype) upperside—I, underside—L.

FIGURE 3. Male genitalia: I. maritimus usambara (Tanzania, Usambara, Gen. prep.: SAFI00375) lateral view—A, aedeagus— D; I. uluguru (holotype, Gen. prep.: SAFI00369) lateral view—B, aedeagus—E; I. collinsi (holotype, Gen. prep.: SAFI00359) lateral view—C, aedeagus—F; I. njombe (Tanzania, Njombe, Gen.prep.: SAFI00366) laterial view—G, aedeagus—J; I. stewarti (Malawi, Nyika Plateau, Gen. prep.: SAFI00210) lateral view—H, aedeagus—K; I. bundali (holotype, Gen. prep.: SAFI00212) lateral view—I, aedeagus—L.

FIGURE 4. Male genitalia (posterior view): I. maritimus usambara (Tanzania, Usambara, Gen. prep.: SAFI00375)—A; I. uluguru (holotype, Gen. prep.: SAFI00369)—B; I. collinsi (holotype, Gen. prep.: SAFI00359)—C; I. njombe (Tanzania, Njombe)— D; I. stewarti (Malawi, Nyika Plateau, Gen. prep.: SAFI00210)—E; I. bundali (holotype, Gen. prep.: SAFI00212)—F.

FIGURE 6. Females: I. maritimus usambara (Tanzania, Usambara) upperside—A, underside—D; I. uluguru (paratype, Tanzania, Uluguru Mountains) upperside—B, underside—E; I. collinsi (paratype, Mozambique, Mount Namuli) upperside—C, underside—F; I. njombe (paratype, Tanzania, Njombe) upperside—G, underside—J; I. stewarti (Malawi, Nyika Plateau) upperside—H, underside—K; I. bundali (paratype, Tanzania, Bundali Hills) upperside—I, underside—L.