Leucobaeta semialba László 2022, comb. n.
Creators: name: László, Gyula M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Nolidae
Leucobaeta
Leucobaeta semialba

description: Leucobaeta semialba (Hampson, 1918) comb. n.
(Figs. 1–3, 17, 23)
Negeta semialba Hampson, 1918, Novitates Zoologicae 25(1): 204. Type locality: [Ghana] Gold Coast, Bibianaha. Holotype, ♀ (NHMUK).
Type material examined. Holotype, ♀, red ring label “Type H.T.” / “ Gold Coast. Bibianaha. 700 ft. XII.1911. H.G.F. Spurrell. 1912-275” / with handwritten: “ Negeta semialba type ♀. Hmpsn.”, QR code label with unique number: NHMUK 010917504 (NHMUK). (Fig. 1)
Additional material examined. Liberia. 1 ♂, Nimba Mts., ENNR, Nimba county (Cellcom road), 1000– 1100m, 7°32’45.88”N, 8°31’21.04”W, 16–28.xii.2018, Cold Cathode UV Light Trap (8W), Sáfián, Sz., Simonics, G. leg., ANHRT:2018.43, unique number: ANHRTUK 00073977, gen. slide No.: LGNA 955; 1 ♂, same site, 2–14.xii.2017, Aristophanous, M., Sáfián, Sz., Simonics, G., Smith, L. leg., ANHRT:2017.33, unique number: ANHRTUK 00142092; 3 ♂, 2♀, Mount Nimba, Cellcom Road, ENNR, Nimba County, 750–1100m, 7°32’35.89”N, 8°31’20.63”W, 14–28.xii.2017, Cold Cathode Light Bucket Trap, Sáfián, Sz., Simonics, G. leg., ANHRT:2017.33, unique numbers: ANHRTUK 00194493-00194496, gen. slide No.: LGNA 1293 (♀); 8 ♂, 1 ♀, Nimba County, Nimba Mts, ENNR, Cellcom road, 750m, 7°33’3.78”N, 8°31’46.49”W, 16–28.xii.2018, Cold Cathode UV Light Trap (8 W), Sáfián, Sz., Simonics, G. leg., ANHRT:2018.43, unique numbers: ANHRTUK 00073958, 00142173, 00142169-00142172, 00219576-00219578 (ANHRT). Nigeria. 1 ♂, Oyo State, Gambari Forest, 6.viii.1977, M.A. Cornes, QR code label with unique number: NHMUK 014046238, gen. slide No.: NHMUK 010316557 (NHMUK).
Diagnosis. In comparison with the Oriental Leucobaeta hemiphaea, L. semialba is considerably smaller in size (forewing length 5.5–8.0 mm, that of hemiphaea is 8.5–9.5 mm), the border of the whitish basal-antemedial area of the forewing is straight, while it is slightly curved in its ventral quarter in the Oriental species. The postmedial fascia consists of a very narrow cream line in L. semialba, while it is marked by a row of three to four black dots anteromedially in L. hemiphaea. In addition, the apical area of the forewing has a large amorphous dark brown patch in the Afrotropical species, whereas it is greyish white, without a distinct dark marking in L. hemiphaea.
In the male genitalia, compared to the type species of the genus, L. semialba has a somewhat longer, basally narrower uncus, and wider, reverse U-shaped medial recess of the tegumen (which is reverse V-shaped in L. hemiphaea). The valva is considerably narrower and longer with a broadly rounded apex in L. semialba, while it is rectangular and distally truncate in the Oriental species. The transtillae are medially fused with a shield-like medial plate in L. semialba, whereas they are connected by a membranous ribbon in L. hemiphaea. The costal process of L. semialba is markedly wider at the base and considerably longer than in L. hemiphaea forming a finger-like process outreaching the ventral margin of the valva, lacking a short, elongate medial crest which is present in the Oriental species. The phallus of L. semialba is armed with a large, robust, curved, claw-like carina, whereas L. hemiphaea lacks a carinal process, but its vesica bears a pair of large, thumbtack-shaped cornuti, which is absent in the Afrotropical species.
Comparing the female genitalia of the Afrotropical and Oriental species, the former has a conical ovipositor, with apically protracted papillae anales, while it is quadrangular and apically rounded, respectively, in L. hemiphaea. The posterior apophyses are longer, while the anterior ones are shorter in L. semialba than in its Oriental congener. The eighth tergite is considerably longer and medially more constricted and the anterior margin of the eighth sternite is evenly curved in both sides in the Afrotropical species, while the eighth sternite bears a pair of short and narrow, slightly conical, apically rounded anterior processes in L. hemiphaea. Further differences are expressed by the markedly shorter and less sclerotized ductus bursae, the much smaller appendix bursae and the presence of signum bursae in L. semialba.
Description. Adult. (Figs. 1–3). Forewing length 5.5–8.0 mm. Antenna fasciculate in male, filiform in female.
Head relatively large, labial palp medium long, rather thick, porrect, pale brown; frons pale brown posteriorly, off-white anteriorly, vertex niveous; compound eye relatively large, globular. Thorax, collar, tegulae and abdomen bright white. Intraspecific variability limited. Sexual dimorphism negligible, expressed only by the somewhat darker hindwing of females.
Forewing relatively short and narrow, rather quadrangular, apically rounded. Basal and antemedial area bright white with a pair of elongate, pale grey costal dashes. Medial area dark brownish-grey, isolated abruptly from basal area by straight, oblique border, postmedial and tornal areas brownish grey, fading somewhat to pale grey towards tornus; dorsal half of postmedial area off-white, with a large round, dark brownish-grey apical patch. Transverse lines poorly visible except for the fine, evenly arcuate, postmedial line well-defined by creamy scales and the very narrow, continuous pale brownish-grey terminal line. Cilia long, darkening from pale grey to dark brown towards tornus.
Hindwing of male off-white in basal half, gradually darkened distally, pale greyish-brown near termen, that of female pale greyish-brown with a small off-white basal area; cilia pale yellowish-brown. Forewing underside dark graphite-grey in dorsal two-thirds, pale greyish-white in ventral third; hindwing underside pale grey, somewhat darker near termen; pattern undetectable.
Male genitalia. (Fig. 17). Uncus medium long, as long as vinculum, broad at base, abruptly tapered medially, gradually tapered distally, pointed apically. Tegumen medium long with narrow arms, medially widely open, arms forming a reverse U-shape. Valva moderately long and broad, as long as tegumen, apically evenly rounded, membranous. Valva costa almost straight, in basal half with a proximally smooth, distally sparsely setose triangular plate serving as a base for well-developed costal process; distal half of costa with narrow marginal sclerotization. Costal process long, medially arched, finger-like with rounded apex outreaching the ventral margin of valva. Sacculus short, broad at base, tapered distally, weakly sclerotized, sparsely setose, conjunct with costal process. Transtillae broad at base, tapered medially and strongly dilated apically, arms fused medially, forming a moderately large, proximally concave, distally rounded, shield-like plate. Fultura inferior (juxta) relatively small, heavily sclerotized, narrow V-shaped. Vinculum rather long, broad at base, abruptly tapered medially into conspicuously narrow, apically rounded, finger-like process (saccus). Phallus tubular, short and thin, straight, medially slightly dilated; coecum penis short and rounded, heavily sclerotized, apex armed with a conspicuously long, robust, medially curved, apically pointed claw-shaped carina process; vesica without cornuti or scobination.
Female genitalia. (Fig. 23). Ovipositor short, conical, papillae anales triangular, apically with a short protracted process, covered in fine setae, apophyses short and thin, apically pointed, posterior ones twice as long as anterior ones. Eighth tergite weakly sclerotized, short, medially constricted. Ostium bursae narrow, more or less round, antrum heavily sclerotized, relatively short, distal margin deeply concave, lateral margins gently arched, proximal margin rounded with a moderately sclerotized, short conical antero-lateral protrusion on right side. Ductus bursae short, membranous, twice as long as sclerotized antrum, medially slightly dilated. Cervix bursae with a short, rounded, sclerotized protuberance on right side. Distal third of corpus bursae conical, proximal part ovoidal, with semi-globular appendix bursae fused with corpus bursae antero-laterally. Signum bursae represented by a small, rounded, fine scobination.
Genetic divergence. Pairwise distance between L. semialba and the Madagascan endemic L. malagassa sp. n. is 7.1% and between L. semialba and the southeast African L. smithi sp. n. is 7.6–7.7%.
Distribution (Fig. 26). This rare species was described from a single female specimen collected in southern Ghana. An additional male specimen was found in the NHMUK collection from Gambari forest, South Nigeria. A short series of specimens was collected on recent ANHRT expeditions at a medium-high elevation in the Nimba Mountains, Liberia.
description: Published as part of László, Gyula M., 2022, On the taxonomy of Negeta semialba Hampson, 1918 with descriptions of two new Leucobaeta László, Ronkay & Witt, 2010 species (Lepidoptera, Nolidae, Nolinae), pp. 56-68 in Zootaxa 5091 (1) on pages 58-63, DOI: 10.11646/zootaxa.5091.1.2, http://zenodo.org/record/5840401