Megagonoleon longidigitus Machado, 2020

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 : 212-215

Megagonoleon longidigitus Machado , new species

( Figs. 101 , 106–107 )

http://zoobank.org/NomenclaturalActs/ ED1724BB-66D7-4664-B1F4-DC3E8B2B9ECA

Diagnosis. Forewing with few apical brown marks; tibial spurs short, about half T1 length; male paramere with anterior margin narrow in ventral view; female ectoproct without cavisetae; female lateral gonapophysis smaller than ectoproct; female membranous digitiform process long.

Description. Lengths: forewing: 22–24 mm; hind wing: 20–21 mm.

Head ( Figs. 106 a–b): Labrum pale; set with a line of elongate setae. Clypeus pale with some elongate pale or black setae. Frons pale but area surrounding antennae dark brown, set with short 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 some white ones on lateral margins. Ocular setae absent. Antennae clubbed; elongate, about three times longer than pronotum; distance between antennae wider than scape width; mostly dark brown, but anterior surface of pedicel and few subapical flagellomeres pale; torular membrane pale; flagellomeres almost as long as wide at base, but apical ones much wider than long; scape and pedicel covered with short white setae, flagellum set with short black setae. Mandibles mostly pale, with tip black. Palpi, maxillary and labial pale with dark brown marks on the basal segments; apical labial palpomere fusiform, palpimacula opening oval-shaped, located medially.

Thorax ( Fig. 107b ): Pronotum slightly wider than long; posterior margin as wide as anterior; subapical furrow present; mostly pale except by a dark brown sagittal band that encircles a pale mark on anterior area and two sinuous lateral bands encircling a pale line on posterior half; beset with short white setae. Mesonotum mostly dark brown except for two pale marks on prescutum, two longitudinal pale bands encircling a small dark area at scutum, and pale lateral and posterior margins of scutellum; covered with short white setae. Metanotum dark brown except by small pale areas as follows: central line of prescutum, two longitudinal bands on scutum, posterior border of scutellum; covered with short white setae. Pterothoracic pleura dark brown with some pale areas on segments border in some specimens; covered with white setae; Miller’s organ present.

Wings ( Fig. 106c ): Rather broad with tip acute; anterior Banksian line present in both wings, but posterior absent; veins mostly dark brown, but with some veins intercalated with white spots, beset with short black setae. Male pilula axillaris present. Forewing membrane mostly hyaline, but with few of brown marks as follows: two longitudinal lines surrounding gradate veins, and three marks, one at tip of subcostal area, other on mediocubital area, and other at base of hypostigmatic cell; tip of pterostigma white but base brown; CuA fork located at level of RP origin or slightly basal in some specimens; three presectoral crossveins; subcostal veinlets simple; posterior area narrower than prefork area at level of CuA fork. Hind wing membrane mostly hyaline except for a small brown mark at base of hypostigmatic cell, and a large rhegmal spot; pterostigma with tip white but base brown; MP fork located at same level of RP origin; subcostal veinlets simple; one presectoral crossvein.

Legs ( Figs. 106 a–b): All pairs of legs, femur elongate (> 2x length of coxa); tibia and femur about same size, and slightly longer than tarsi; tibial spurs slightly shorter than half of T1 length; T2, T3 and T4 about same size, T1 slightly longer than T2, but shorter than T5; claws slightly longer than half of T5 length; coxa, trochanter and most femur set with short white setae; femur apex, 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 pale, femur pale with apex dark brown, but in some specimens the pale area slightly darker on external surface, tibia intercalated with three pale and three dark brown rings; tarsi pale, except for T5 tip, dark brown. Mesoleg with same colour pattern to proleg, except for some irregular pale marks on coxa. Metaleg with femur, tibia and T1 slightly longer than in other legs; colour pattern similar to mesolegs, except for tibia entirely pale with tip dark brown.

Abdomen: Tergites dark brown with longitudinal pale areas laterally. Sternites entirely dark brown or with central pale marks in some specimens. All segments covered with short white setae.

Male Terminalia ( Figs. 107 a–d): Ectoproct posterior margin rounded in lateral view, set with elongate black setae. 9 th sternite short, with posterior margin straight and set with elongate black setae in ventral view. Gonarcus broad with anterior margin straight in lateral view; medially arched and laterally curved in posterior view. Mediuncus extending downwards in lateral view; broad and rounded in posterior view. Paramere in lateral view curved, with anterior margin acute and posterior rounded; in posterior view broad with ventral margin curved; in ventral view, with inner region rounded and exterior region thin and curved.

Female Terminalia ( Figs. 107 e–f): Ectoproct posterior margin rounded and covered with thin elongate setae. Lateral gonapophyses rounded, smaller than ectoproct, set with few cavisetae and elongate black setae. 7 th sternite distal margin straight and covered with short black setae in ventral view. Pregenital plate in ventral view large and “kite” shaped, with anterior region larger than posterior; anterior and posterior corners curved but lateral corners acute; posterior area with a medial rounded concave region. Posterior gonapophyses elongate, with tip rounded and covered with long black setae. 9 th tergite with a long membranous digitiform process. Anterior gonapophyses absent. Ventral membrane gonapophyseal plates present.

Distribution ( Fig. 101 ). Australia: WA. Known only from the Pilbara region of Western Australia.

Adult activity period. Records for August, October, and November.

Biology. Unknown, larva unknown.

Etymology. longi- (from Latin longus, long) + -digitus (from Latin digitus, finger), in reference to the extremely elongate membranous digitiform process of the female terminalia. Treated as a compound noun in apposition.

Name-bearing type. Megagonoleon longidigitus : Holotype (by present designation), male, ANIC. AUSTRA- LIA: Western Australia: ½ km SSW of Millstream homestead, 21.35S– 117.04E, 4.xi.1970, Upton & Feehan. Condition: pinned, good, right antenna missing and left metaleg with last two tarsomeres missing; terminalia dissected.

Paratypes (3♂, 2♀). AUSTRALIA: Western Australia: Fortescue River : 29.viii.1964 (1♂, ANIC, pinned); ½ km SSW of Millstream homestead, 21.35S– 117.04E, 27.x.1970, Upton & Feehan (1♀, ANIC, pinned); 3.xi.1970, MS Upton (2♂, 1♀, ANIC, pinned) .

Comments. Megagonoleon longidigitus sp. nov. is closely related to M. tillyardi . Both species share many similarities, particularly the extremely elongate digitiform process of the female terminalia and a relatively small lateral gonapophysis. These characteristics distinguish them from all other species of Megagonoleon gen. nov., within which both morphological ( Fig. 4 ) and molecular data ( Machado et al. 2019, fig. 4 as “ Glenoleon sp.2”) recover them as part of a small clade near the base of the genus. These two species also share short tibial spurs, but can be separated by body and wing color patterns and male paramere shape.

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 101. Distribution of Megagonoleon species (part).

FIGURE 106. Megagonoleon longidigitus sp. nov.: a) head, anterior; b) head and thorax, dorsal; c) wings, dorsal.

FIGURE 107. Megagonoleon longidigitus sp. nov.: male: a) terminalia, lateral; b) genitalia, lateral; c) genitalia, ventral; d) genitalia, posterior; female: e) terminalia, lateral; f) 7th sternite and pregenital plate, ventral. Scale bars = 0.5 mm.