Riekoleon edwardsi (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 : 294-297

Riekoleon edwardsi (New, 1985) , new combination

( Figs. 153 , 156–157 )

http://zoobank.org/NomenclaturalActs/ 977D5CD5-FEBF-42B9-80BA-C588CFC1D9E9

Austrogymnocnemia edwardsi New, 1985b:17 (OD); New 1996:67 (cat.); Stange 2004:99 (cat.); Oswald 2018 (cat).

Diagnosis. Forewing: first fork of RP in proximal half of wing, dark longitudinal line continuous from near wing base to near apex; hind wing rhegmal mark large; male ectoproct with ventral margin straight; female posterior gonapophysis wider than long; female anterior gonapophysis a small plate.

Description. Lengths: forewing: 21–26 mm; hind wing: 19–24 mm.

Head ( Figs. 156 a–b): Labrum pale to brown, with a line of elongate setae. Clypeus pale, with a thin longitudinal black line medially on dorsal half, some specimens with irregular lateral brown marks, set with few elongate black setae. Frons with ventral area pale with a thin longitudinal black line medially, remaining areas black; set with few small white setae. Gena pale. Vertex raised; mostly pale with a transverse dark brown band posteriorly; set with small black setae. Ocular setae absent. Antennae clubbed; elongate, about twice longer than pronotum; distance between antennae wider than scape width; all segments dark brown, torular membrane yellow; flagellomeres almost as long as wide at base, apical ones much wider than long; all segments set with short black setae; scape and pedicel with some white setae. Mandibles pale with tip dark brown. Palpi, maxillary and labial with basal segment dark brown but remaining areas pale with irregular brown areas, in some specimens the whole maxillary palpi is dark brown, apical labial palpomere fusiform, palpimacula opening large and rounded, located medially.

Thorax ( Fig. 156b ): Pronotum slightly longer than wide; posterior margin wider than anterior; subapical furrow present; mostly pale with some dark brown areas as follows: a broad longitudinal medial line, two longitudinal sinuous lines that connect with medial line on anterior margin, posterior half with two lateral sinuous lines that connect with the longer sinuous lines on furrow; covered with short black setae. Mesonotum mostly dark brown, with two rounded pale spots at prescutum, two large pale areas enclosing a longitudinal dark brown line at scutum, small pale spots near wing bases, and posterior margin of scutellum pale, covered with short black setae. Metanotum dark brown with irregular pale marks near midline, covered with short black setae. Pterothoracic pleura black; covered with short black setae and few white setae. Miller’s organ present.

Wings ( Fig. 156c ): Rather narrow with tip acute; anterior Banksian line present in both wings, posterior absent; veins set with short black setae, in general brown, but the main longitudinal veins are intercalated by numerous short white regions. Male pilula axillaris present. Forewing membrane mostly hyaline with a long longitudinal brown line, starting costal area base and extending on subcostal area base, base of presectoral area, whole mediocubital area, and gradate veins up to apex, this line bifurcates at the CuA fork and follows CuA first branch and the curved vein at cubital area; with some irregular brown marks, at the inferior margin, apex, and base of pterostigma; tip of pterostigma white; CuA fork located near RP origin; three presectoral crossveins; subcostal veinlets simple; posterior area narrower than prefork area. Hind wing membrane mostly hyaline except for small brown marks at apex, and a large brown mark on rhegmal region; pterostigma base brown and apex white; MP fork located near RP origin; subcostal veinlets simple; one presectoral crossvein.

Legs ( Figs. 156 a–b): All pairs of legs, femur elongate (> 2.5x length of coxa); tibia slightly longer than femur but twice longer than tarsi; tibial spurs absent in some specimens but extending to T2 apex in others; T2, T3 and T4 about same size, T1 longer than T2, T5 longer than T1; claws about half of T5 length; all segments set with short black setae, with scattered longer black setae at femur, tibia, and tarsi; T5 ventrally with two rows of thick, long, black setae. Proleg sense hair slightly longer than femur width; tibia with antennal cleaning setae ventroapically; coxa black; trochanter brown; femur dark brown; tibia mostly dark brown with pale marks on dorsal surface: two small marks on basal half and a large one apically, part of ventral surface pale in some specimens; tarsi entirely dark brown, but with the base of T1 pale in some specimens. Mesoleg with colouration similar to proleg, except for femur with pale marks at basal part of ventral surface in some specimens. Metaleg femur and tibia slightly longer than in other legs, colour pattern similar to mesoleg except for pale tibia with tip dark brown and some specimens with a brown line on ventral surface; tarsi generally paler.

Abdomen: black, with some pale areas on sternites midline in some specimens; beset with short black setae.

Male Terminalia ( Figs. 157 a–d): Ectoproct with ventral margin straight and longer than dorsal margin in lateral view; set with elongate black setae. 9 th sternite with posterior margin elongate medially in ventral view; ventrally extended in lateral view. Gonarcus broad and arched; in lateral view with anterior margin smaller and in posterior view with dorsal margin straight medially. Mediuncus absent. Paramere large, triangular in lateral view; in posterior view curving inwards, with apex rounded and more sclerotized.

Female Terminalia ( Figs. 157 e–g): Ectoproct posterior margin rounded, set with long black setae. Lateral gonapophyses rounded, shorter than ectoproct, beset with short black setae. 7 th sternite long, distal margin with a rounded expansion medially, set with elongate black setae. Pregenital plate with posterior part thin and anterior margin enlarged in posterior view; curved in ventral view. Posterior gonapophyses broader than long, with distal margin wider than basal; beset with very long black setae and numerous cavisetae at apex. 9 th tergite with a broad membranous digitiform process. Anterior gonapophyses a small plate covered with long setae. Ventral membrane gonapophyseal plates present.

Distribution ( Fig. 153 ). Australia: NSW, QLD, WA. Known from sparse records in southern Western Australia and eastern Queensland and New South Wales; one of only three Riekoleon species (with R. rudda and R. striatus ) currently reported from both western and eastern Australia.

Adult activity period. Records for December and January.

Biology. Unknown, larva unknown.

Name-bearing type. Austrogymnocnemia edwardsi : Holotype (by original designation), female, ANIC, examined. Type locality: Australia, New South Wales, 6 km WSW Bingara (town). From original description: “ Holotype, ♀, New South Wales, 6 km WSW. Bingara, 8.xii.1974, I. F. B. Common, E. D. Edwards (150°31’E., 29°53’S.) ( ANIC)”. Condition: relatively good; right antenna missing; body covered with some white mold; terminalia dissected.

Additional material examined (5♂, 10♀). AUSTRALIA: Western Australia: Leonora : 16.i.1989, M.S. & B.J. Moulds (1♂, AMSA) ; 10 km N of Menzies , 14.i.1989, M.S. & B.J. Moulds (3♀, AMSA) ; 55 km ESE of Mount Magnet , 18.i.1989, M.S. & B.J. Moulds (3♂, 2♀, AMSA) ; Oakford: Ankeletes Road , 32.13S– 115.54E, 28.i.1998, E.D. Edwards & E.S. Nielsen (3♀, ANIC) ; 25 km E of Sandstone , 17.i.1989, M.S. & B.J. Moulds (1♂, 2♀, AMSA) .

Comments. Riekoleon edwardsi is similar to R. rudda in the shape of the male terminalia and the length of the pronotal setae. But, the dark longitudinal line of the forewing in R. edwardsi , which runs from the base of the wing to near its apex, easily separates the two. Given the notably high variability in tibial spur presence and length among the species of the Periclystus genus group, it is interesting to note that R. edwardsi exhibits intraspecific variation in this trait. While the specimens of the type series of R. edwardsi lack tibial spurs (confirmed here), most of the new specimens attributed to this species here (based on clear male and female terminalic traits and shared body colour patterns) have tibial spurs present (typically reaching the apex of the second tarsomere). Closer examination of other species for the possible presence of intraspecific variation in tibial spur state, and for possible simple genetic mechanisms controlling such variation, would be interesting avenues to explore in search of explanations for interspecific variation in this trait within the Periclystus genus group, and indeed, more broadly across the Myrmeleontidae . 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 153. Distribution of Riekoleon species (part).

FIGURE 156. Riekoleon edwardsi: a) head, anterior; b) head and thorax, dorsal; c) wings, dorsal.

FIGURE 157. Riekoleon edwardsi: male: a) terminalia, lateral; b) 9th sternite, ventral; c) genitalia, lateral; d) genitalia, posterior; female: e) terminalia, lateral; f) terminalia, ventral (note pregenital plate hidden beneath sternite); g) pregenital plate, posterior. Scale bars = 0.5 mm.