Megagonoleon nigrescens (New, 1985)

Machado, Renato Jose Pires & Oswald, John David, 2020, Morphological phylogeny and taxonomic revision of the former antlion subtribe Periclystina (Neuroptera: Myrmeleontidae: Dendroleontinae), Zootaxa 4796 (1), pp. 1-322 : 223-226

Megagonoleon nigrescens (New, 1985) , new combination

( Figs. 110 , 113–114 )

http://zoobank.org/NomenclaturalActs/ 0C70E1F2-8138-4C9F-BB3E-07A8853084A5

Austrogymnocnemia nigrescens New, 1985:24 (OD); New 1996:68 (cat); Stange 2004:99 (cat); Oswald 2018 (cat); Machado et al. 2019 (tree).

Diagnosis. Forewing with numerous brown marks; hind wing with rhegmal spot small; clypeus with two dark brown spots; tibial spurs absent; female lateral gonapophysis about same size as ectoproct; female posterior gonapophysis without cavisetae; male mediuncus mostly membranous with a central sclerotized triangle.

Description. Lengths: forewing: 20–22 mm; hind wing: 18–21 mm.

Head ( Figs. 113 a–b): Labrum pale to light brown; set with a line of elongate setae. Clypeus pale with two lateral curved brown spots dorsally; set with some elongate black setae. Frons dark brown, covered with many white setae. Gena pale. Vertex raised; in anterior view pale, with two short transverse dark brown marks laterally and a rounded central dark spot; in dorsal view mostly pale with two central perpendicular dark brown lines and two black marks posterolaterally; covered with short black setae, and few white ones on posterior margin. Ocular setae very short and white. Antennae clubbed; elongate,> 3x length of pronotum; distance between width; mostly dark brown, with distal margin of basal flagellomeres pale, and three or four subapical flagellomeres pale on anterior surface; torular membrane pale; flagellomeres almost as long as wide at base, apical ones much wider than long; scape and pedicel covered with short white setae, flagellum set with small black setae. Mandibles mostly pale, with tip black. Palpi, maxillary and labial mostly pale with dark brown marks (entirely dark brown in some specimens); apical labial palpomere fusiform, palpimacula opening oval-shaped, located medially.

Thorax ( Fig. 113b ): Pronotum wider than long; posterior margin as wide as anterior; subapical furrow present; mostly pale except for some dark brown areas as follows: a broad medial band, and two sinuous bands laterally encircling a pale area on posterior half; beset with white setae mostly short with some marginal long setae, some specimens with few black setae in posterior margin. Mesonotum mostly dark brown to grey (in general medial area darker) with two longitudinal yellow bands around central area; covered with short white setae and some black setae on prescutum. Metanotum colour similar to mesonotum; covered with short white setae. Pterothoracic pleura dark brown with some pale areas on sclerites borders in some specimens; covered with white setae; Miller’s organ present.

Wings ( Fig. 113c ): Fairly broad with tip acute, anterior and posterior Banksian lines present in both wings, veins mostly dark brown, but some veins intercalated with white spots, and others completely white, beset with short black setae. Male pilula axillaris present. Forewing membrane mostly hyaline but with numerous brown marks in posterior margin, pterostigma, subcostal area, mediocubital area, around radial crossveins, and two apical lines surrounding gradate veins; tip of pterostigma white; CuA fork located near RP origin; three or four presectoral crossveins; subcostal veinlets simple; posterior area narrower than prefork area. Hind wing membrane mostly hyaline except for a small brown mark beneath pterostigma, and a small rhegmal spot; pterostigma tip white; MP fork located near RP origin; subcostal veinlets simple; one presectoral crossvein.

Legs ( Figs. 113 a–b): All pair of legs, femur elongate (about twice longer than coxa); tibia, femur and tarsi about same size; tibial spurs absent; T2, T3 and T4 about same size, T1 and T5 about same size, near twice longer than T2; claws slightly longer than half of T5 length; coxa, trochanter, femur, and tibia set with short white setae; femur, tibia and tarsi set with short black setae, and scattered long black setae; T5 ventrally with two rows of thick, long, black setae. Proleg sense hair absent; tibia with antennal cleaning setae ventroapically; coxa dark brown, trochanter light brown, femur dark brown with internal surface pale, tibia mostly pale with three dark brown marks on anterior surface; tarsi dark brown, except T1, pale. Mesoleg with same colour pattern of proleg, except for tibia in some specimens, dark brown with three pale rings. Metaleg with femur, tibia and T1 slightly longer than in other legs; colour pattern similar to anterior legs, except for tibia pale with tip dark brown.

Abdomen: Dark brown; set with short white setae.

Male Terminalia ( Figs. 114 a–d): Ectoproct posterior margin rounded in lateral view; set with elongate black setae. 9 th sternite short, with posterior margin concave in ventral view; set with elongate black setae. Gonarcus simple, arched, with anterior margin enlarged ventrally in lateral view. Mediuncus mostly membranous except by a central sclerotized triangle in posterior view. Paramere in lateral view “C” shaped, with ventral area long and acute.

Female Terminalia ( Figs. 114 e–f): Ectoproct posterior margin rounded, set with thin elongate setae and some cavisetae ventrally. Lateral gonapophyses rounded, about same size of ectoproct, beset with cavisetae. 7 th sternite elongate with distal border straight in ventral view; covered with short setae. Pregenital plate small, weakly sclerotized, rounded anteriorly. Posterior gonapophyses thin, elongate, and with apex slightly wider than base, beset with black setae. 9 th tergite with a very short membranous digitiform process. Anterior gonapophyses absent. Ventral membrane covered with short setae medially.

Distribution ( Fig. 110 ). Australia: NT, QLD, WA. Known from scattered records across northwestern and north-central Australia. New (1985b) also reported specimens from SA and ACT; upon re-examination those specimens proved to be misidentifications of Austrogymnocnemia pseudomaculata sp. nov.

Adult activity period. Records for August to October, December, and March to June; not recorded from the hottest summer months.

Biology. Unknown, larva unknown.

Name-bearing type. Austrogymnocnemia nigrescens : Holotype (by original designation), female, MVM, examined. Type locality: Australia, Western Australia, Forrest River Mission. From original description: “ Holotype, ♀, Western Australia, Forrest R. Mission, 20.viii.1953, K.J.C. ( MVM)”. Condition: good; terminalia dissected.

Additional material examined (28♂, 49♀, 1?). AUSTRALIA: Northern Territory: Alice Springs : x.1972 (1♂, ANIC) ; 46 km SSW of Borroloola , 16.28S– 136.09E, 28.x.1975, M.S. Upton (1♂, 1♀, ANIC) ; Devil’s Mar- bles: 7mi N of Wauchope, 22.iv.1966, N. McFarland (1♂, 4♀, SAMA) ; xi.1961 (1♂, 1♀, FSCA) ; ix.1967 (1♀, MVM) ; Roper Bar : iv.1966 (1♀, SAMA) ; Queensland: Lawn Hill National Park : v.1995 (1♀, 1♂, ANIC) ; Western Australia: 145 km SE of Broome , 18.55S– 123.27E, viii.1976, I.F.B. Common (5♂, 17♀, ANIC) ; 8 km SWbyW of Cane River Homestead, 22.07S– 115.33E, 31.iii.1971, E.F. Riek (1♀, TAMU; 7♂, 5♀, ANIC) ; 21.56S– 115.39E, 27.iv.1971, Upton & Mitchell (2♂, ANIC) ; iv.1971 (1♂, ANIC) ; Fitzroy Crossing : ix.1953 (1♂, 1?, SAMA) ; Halls Creek : 1.x.1953, N.B. Tindale (1♀, SAMA) ; v.1964 (1♀, ANIC) ; 85 km ESE of Halls Creek , 18 o 24’S– 128 o 28’E, 4.vi.1998, M.V., JD Oswald (1♂, 2♀, TAMU) ; Halls Creek : x.1953 (1♀, SAMA) ; 70 mi ESE of Kununurra , iv.1965 (2♂, 1♀, SAMA) ; Lulingui Station: near Derby , 26.viii.1929, I.M. Mackerras & T.G. Campbell (2♀, ANIC) ; Mill- stream Chichester National Park: Python Pool , 21.33309 oS– 117.23930 oE ± 130m, 180m, 23.xii.2012, M.V., Oswald, Diehl & Machado, Oswald #615 (1♂, 2♀, TAMU) ; Minilya Station : iv.1953, A. Snell (1♂ PT, MVM) ; iv.1953 (1♂, MVM) ; Moola Bulla Station : viii.1994 (1♀, ANIC) ; Highway 136, 13 air km NENE of Nanutarra Road- house, 22.47124 oS– 115.60040 oE ± 70m, 130m, 22.xii.2012, M.V., Oswald, Diehl & Machado, Oswald #614 (1♂, 2♀, TAMU) ; Palm Springs: 38 road km SE Halls Creek , 18 o 25’23’’S– 127 o 50’45’’E, 11.vi.1998, M.V., JD Oswald (1♀, TAMU) ; Pilgangoora Well : v.1953 (1♀, SAMA) ; 0.5 km E of Pungkulpirri Waterhole, Walter James Rg, 24 o 39’15’’S– 128 o 45’18’’E, 26.ix.2006, at light, Central Ranges Sur. Camp 1 (2♀, SAMA) ; Winttenoon : x.1961 (1♀, FSCA) .

Comments. New (1985b) noted the similarity of M. nigrescens and Austrogymnocnemia maculata , based on their heavily marked forewings. This similarity, however, is superficial, as these species differ significantly in male and female terminalic form. Within Megagonoleon gen. nov., M. nigrescens can be distinguished based on overall colouration and terminalic shape. For phylogenetic relationships see Fig. 4 .

Figures

FIGURE 4. Strict consensus tree of morphology-based parsimony analysis of species belonging to the former subtribe Periclystina (ingroup, names in black), and outgroups (names in red). Former Glenoleon species are shown on blue branches, former Austrogymnocnemia species on green branches. Numbers above branches are Bremer support values; numbers below branches are bootstrap values (shown where>50%).

FIGURE 110. Distribution of Megagonoleon species (part).

FIGURE 113. Megagonoleon nigrescens: a) head, anterior; b) head and thorax, dorsal; c) wings, dorsal.

FIGURE 114. Megagonoleon nigrescens: male: a) terminalia, lateral; b) genitalia, lateral; c) genitalia, posterior; d) 9th sternite, ventral; female: e) terminalia, lateral; f) 7th sternite and pregenital plate, ventral. Scale bars = 0.5 mm.