Shimbania mbarikaensis, Lehmann & Dalsgaard, 2023

Lehmann, Ingo & Dalsgaard, Thure, 2023, Revision of Saalmulleria Mabille, 1891 (Lepidoptera, Metarbelidae) from Madagascar with the description of three new genera and fifteen new species, Evolutionary Systematics 7 (1), pp. 133-182 : 133

Shimbania mbarikaensis sp. nov.

Figs 2d , 9c

Material examined.

Holotype male, Tanzania, Morogoro Region, Mbarika Mountains [also called Mbaraka Mountains, cf. Kielland 1990], "sud de Mahenge forêt” [= south of Mahenge Forest], 775 m, 22.April 2005, Ph. Darge [leg.], genitalia slide number 01/032009 I. Lehmann (MWM). Paratype male, same locality, "nr. Mahenge Forest " [near Mahenge Forest], 775 m, 22.-23. April 2005, R. Minetti [leg.], genitalia slide number 023/072016 I. Lehmann (RMCA).

Description.

Male. Head: ventrally dark-olive (without any chestnut colour), the rest is deep olive-buff, short scales with cream tips, glossy; eyes light brownish-olive with few small black spots and surrounded by long hair-like scales of dark-olive ventrally with a glint; a pair of pits is rudimentary on lower fronto-clypeus, a pair of rudimentary projections also present; pits behind labial palpi are narrow slits; antenna long, 0.41 length of forewing, bipectinate, shaft broad, branches long, 3.0 × width of shaft, not scaled, all branches are widely separated at base, but only 1.0 × width of branch (cf. Shimbania kaguruensis sp. nov.); shaft covered with ivory-yellow scales dorsally; labial palpi long, almost as long as eye-diameter, deep olive-buff.

Thorax: Patagia deep olive-buff, forming a collar ring, scales with light grey tips; tegulae with long hair-like dark chestnut scales with a light lilac glint. Metathorax have a scale-crest of deep olive-buff with a dark chestnut center. Hind legs deep olive-buff with fine hair-like scales with light grey tips, on lower part of tarsus dark olive dorsally; two pairs of long tibial spurs of unequal width and length, upper pair narrow ca. 1.9 mm and 2.1 mm, lower pair broader ca. 1.9 mm and 1.8 mm long. Forewing length 23.0 mm (22.0 mm in paratype) and wingspan is 49.0 mm (48.0 mm in paratype). Forewing upperside deep olive-buff with a light golden glint, only costal margin citrine-drab; below first half of 1A+2A a sepia patch; forewing with many narrow dark olive lines from costa to dorsum, most veins distinctly marked sepia including CuA2; a large and dark olive subterminal patch, broadly V-shaped, from R3 to near end of CuA1; termen without lunules; cilia short, 1.0 mm, deep olive-buff with grey tips and a glint. Underside of forewing is deep olive-buff with weak brownish-olive lines, citrine-drab along costa and a golden glint. Hindwing upperside is pale olive-buff with a light golden glint and weak brownish-olive lines; cilia as in forewing; underside as in forewing.

Abdomen: Deep olive-buff mixed with ivory-yellow hair-like scales with a light golden glint; abdominal tuft with hair-like scales of deep olive-buff and ivory-yellow, medium long, 1/4 length of abdomen. Genitalia with long uncus, 60% of length of whole gnathos, narrow graben-like surface ventrally is absent. Gnathos has gnathos arms that are large, one arm 45% the size of valva; upper part of the gnathos arm is a long band as long as 70% of basal width of valva, the lower part of the gnathal arm does not touch the other arm, it is of broad rectangular shape with a pronounced thorn-like structure and with its base 65% of the basal width of valva, a strongly serrate dorsal edge with two short thorn-like structures is present; the gnathal arms are connected ventrally by a narrow sclerotized band that is as broad as 20% of the transtilla and is widely bifurcated at the middle (also in paratype). The Gnathos arms end above the dorsal edge of the transtilla. The valva is broadly rectangular with a dorsal edge of 2.0 × the length of uncus, ventral edge of valva oblique, almost C-shaped (also in paratype), not S-shaped, with a tip that is broadly rectangular; sacculus not pronounced, broad, weakly sclerotized, 45% of length of ventral edge of valva; juxta well developed, with two ear-shaped lobes and a narrowly V-shaped emargination in between that is 60% the length of juxta, tips of lobes rounded. Phallus very large, as broad as 40% of basal width of valva and 40% longer than costal width of valva, strongly S-shaped and bent upwards at tip distally, vesica without cornuti.

Female. Unknown.

Diagnosis.

Shimbania mbarikaensis sp. nov. can be separated from all other congeners by its shape of the valvae that are broadly rectangular and elongated with an oblique ventral edge that is almost C-shaped and is not suddenly bent inwards. This shape of the valvae is similar to S. baginerichardi sp. nov., but in the latter species, the valvae are short with a dorsal edge of only 1.3 × the length of uncus while in S. mbarikaensis sp. nov. the dorsal edge is 2 × the length of uncus (the uncus has the same length in both species). Both species differ in the width of the tegumen (viewed ventrally) that is only 30% as broad as the basal width of valva in S. mbarikaensis sp. nov. but 50% as broad as the basal width of valva in S. baginerichardi sp. nov. The dark-olive as well as deep olive-buff head (without any chestnut colour) is remarkable and differs to S. puguensis sp. nov. and S. pwaniensis sp. nov. that have mainly dark chestnut scales on the head.

Distribution.

Shimbania mbarikaensis sp. nov. is only known from an submontane habitat south of Mahenge Forest. Kielland (1990) described the “Mbaraka” (= Mbarika) Mountains as seen from Muhulu Forest (located south of Mahenge Forest at 8°49'57"S, 36°39'32"E) as "uninhabited … several patches of forest on hilltops". The Mbarika-Mahenge mountain chain belongs to the "southern Eastern Arc Mountains" ( Lovett 1998) and is located ca. 290-300 km inland from the coast of the Indian Ocean. The isolated forest patches on hilltops as seen by Jan Kielland have high species diversities as well as species of restricted distribution, e.g. trees like Allanblackia stuhlmannii Engl. ( Guttiferae ) and Dombeya amaniensis Engl. ( Sterculiaceae ). The forests are edged by woodland with scattered trees, e.g. Combretum molle R. Br. ( Combretaceae ) and Erythrina abyssinica Lam. ( Leguminosae - Papilionaceae ) (CELP 2007). The altitudinal range of submontane forest is from ca. 700-1.300 m; montane forest from 1.300 m - ca. 1.477 m. The Mbarika-Mahenge mountain chain is among the four Eastern Arc Mountains with the most pronounced dry season. Hence, Shimbania mbarikaensis sp. nov. is classified here as a submontane species of drier forest and/or woodland that is endemic to the Mahenge-Mbarika mountain chain (altitude up to 1.496 m; combined forest cover of all patches 291 km2 with very little closed forest cf. Newmark 2002). Due to the small size of all forest patches on this mountain chain S. mbarikaensis sp. nov. is potentially threatened.

Etymology.

Shimbania mbarikaensis is named for the Mbarika-Mahenge mountain chain (Tanzania) that is the least scientifically studied among the Eastern Arc Mountains, and is among the three mountains with the highest losses of original forest cover in the last 200 years (89.3%) ( Newmark 2002).

The gender of the new species name is feminine.

Figures

Figure 2. a. Shimbania pwaniensis sp. nov., holotype, male, Tanzania, Pwani Region, road from Dar es-Salaam to Chalinze, near the railway crossing, ca. 2 km from Ruvu River; b. S. puguensis sp. nov., holotype, male, Tanzania, Pwani Region, Pugu Forest; c. S. kaguruensis sp. nov., holotype, male, Tanzania, Morogoro Region, Kaguru Mountains; d. S. mbarikaensis sp. nov., holotype, male, Tanzania, Morogoro Region, Mbarika Mountains, south of Mahenge Forest; e. S. kerstinhempae sp. nov., holotype, female, Tanzania, Arusha Region, Usa River, Danish Volunteer Training Centre.

Figure 9. a. Shimbania puguensis sp. nov., paratype, male, Tanzania, Pwani Region, Kisarawe Forest; b. S. kaguruensis sp. nov., holotype, male, Tanzania, Morogoro Region, Kaguru Mountains; c. S. mbarikaensis sp. nov., holotype, male, Tanzania, Morogoro Region, Mbarika Mountains (also called Mbaraka Mountains), south of Mahenge Forest; d. S. wanjakinuthiaae sp. nov., holotype, male, Republic of South Africa, Province KwaZulu-Natal, ca. 5 km north of Hluhluwe, probably collected on Hluhluwe Farm.