Riekoleon distivenus 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 : 290-294

Riekoleon distivenus Machado , new species

( Figs. 153–155 )

http://zoobank.org/NomenclaturalActs/ FA4F57FE-89BC-44F0-B9D8-3A661FEF50DB

Diagnosis. Pronotum longer than wide; forewing: first fork of RP in distal half of wing; tibial spurs absent; male ectoproct without a tubular posteroventral lobe; female posterior gonapophysis wider than long; female anterior gonapophysis absent.

Description. Lengths: forewing: 15–18 mm; hind wing: 13–16 mm.

Head ( Figs. 154 a–b): Labrum white to pale, with a line of elongate setae. Clypeus white to pale, with few elongate pale setae. Frons ventral margin pale (with a thin central longitudinal dark brown line in some specimens), remaining areas shiny black (dorsal margin curved and ventral medially excavated); covered with short white setae. Gena white to pale. Vertex raised; in anterior view white to pale with dark brown marks, mainly on medial line; in dorsal view dark brown with posterior margin pale; covered with short black setae. Ocular setae absent. Antennae clubbed; elongate, about twice longer than pronotum; distance between antennae wider than scape width; scape, pedicel and most flagellomeres dark brown with a white to pale ring on distal margin, apical segments entirely dark brown, in some specimens three to four subapical flagellomeres entirely pale; torular membrane white to pale; flagellomeres almost as long as wide at base, apical ones much wider than long; all segments set with short black setae. Mandibles white to pale, with tip dark. Palpi, maxillary and labial with all segments dark brown but connection between them white to pale; apical labial palpomere fusiform, palpimacula opening oval-shaped, located medially.

Thorax ( Fig. 154b ): Pronotum much longer than wide; posterior margin wider than anterior; subapical furrow present; mostly dark brown with pale to white areas as follows: two sinuous longitudinal lines that are medially fused after furrow, a small central mark posteriorly; beset with short black setae and few long black setae on borders. Mesonotum mostly dark brown with white to pale areas as follows: two square marks on prescutum, two longitudinal lines near midline, a rounded spot at wings base at scutum, two posterior triangular marks at scutellum; covered with short black setae. Metanotum colour similar to mesonotum, covered with few short black setae. Pterothoracic pleura mostly dark brown with some irregular pale marks, mainly on dorsal segments; covered with white setae; Miller’s organ present.

Wings ( Fig. 154c ): Rather narrow with tip acute; anterior Banksian line present in both wings, posterior absent; veins mostly dark brown, but some veins intercalated with white spots, beset with short black setae. Male pilula axillaris present. Forewing membrane mostly hyaline but with numerous irregular large brown marks particularly around crossveins but with a large mark beneath pterostigma; basal costal and subcostal areas brown shaded; CuA fork located near RP origin; RP first fork on distal half of wing; three to five presectoral crossveins; subcostal veinlets simple; posterior area narrower than prefork area. Hind wing membrane mostly hyaline except for large rhegmal and stigmal marks and some irregular brown marks around major crossveins; central and inferior areas brown shaded; MP fork located between origins of RP origin and first fork; RP first fork on distal half of wing; subcostal veinlets simple; one presectoral crossvein.

Legs ( Figs. 154 a–b): All pairs of legs, femur elongate (> 2.5x length of coxa); tibia slightly longer than femur and longer than tarsi; tibial spurs absent; T3 and T4 about same size, T2 slightly longer than T3, T1 and T5 about same size but near twice longer than T2; claws shorter than half of T5 length; coxa, trochanter, and femur set with short white setae, and scattered long setae; femur, tibia and tarsi set with 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 externally dark brown but internally white to pale, trochanter brown, femur mostly brown with internal surface white to pale particularly at base, tibia brown with two white to pale rings, both at basal half, but some specimens with a ventroapically pale mark; tarsi dark brown. Mesoleg with colour pattern similar to proleg, except for femur mostly white to pale with apex and part of dorsal surface brown, and tibia generally darker. Metaleg with femur and tibia slightly longer than in other legs; colour pattern similar to mesoleg, except for tibia white to pale with tip and internal surface midline dark brown, and tarsi paler.

Abdomen: Mostly black with scattered white to pale marks, mainly on sternites medial and lateral areas, and tergites proximal halves. Beset with short black setae.

Male Terminalia ( Figs. 155 a–c): Ectoproct with ventral margin straight and longer than dorsal margin in lateral view, set with elongate black setae. 9 th sternite posterior margin rounded in ventral view; covered with elongate black setae. Gonarcus broad and arched, in dorsal view; in posterior view there is a small expansion at corners of ventral margin. Mediuncus absent. Paramere large, in lateral view curving backwards; in posterior view with tip straight and internal margin curved.

Female Terminalia ( Figs. 155 d–e): Ectoproct posterior margin rounded covered with thin elongate setae. Lateral gonapophyses rounded, much smaller than ectoproct, set with few elongate setae. 7 th sternite elongate, with distal margin rounded, in ventral view; set with long black setae. Pregenital plate a small curved transverse bar in ventral view. Posterior gonapophyses broad, wider than long covered with long black setae and with numerous cavisetae apically. 9 th tergite with a broad membranous digitiform process. Anterior gonapophyses absent. Ventral membrane gonapophyseal plates absent.

Distribution ( Fig. 153 ). Australia: WA. Known from sparse records in southern Western Australia.

Adult activity period. Records for November and December.

Biology. Unknown, larva unknown.

Etymology. disti- (from Latin distantia, distal or far) + -ven- (from Latin vena, vein) + -us (from Latin -us, pertaining to), in reference to the relatively distal position of the first fork of the forewing RP vein.

Name-bearing type. Riekoleon distivenus : Holotype (by present designation), female, AMSA. AUSTRALIA: Western Australia: 25 km S of Balladonia Roadhouse ; 32:33:65S–123.37:10, 16.Dec.1995, M.S. & B.J. Moulds. Condition: pinned; perfect; terminalia dissected.

Paratypes (7♂, 13♀). AUSTRALIA: Western Australia: Cave Rock Camp: 28.6 km S of Burra Rock, - 31.640S– 121.209E, 17.xi. 2007, 380m, at light, D.R. Britton & D.J. Bicket (2♂, AMSA, pinned); Dundas Nature Reserve: 22,8 air km SWSW Balladonia Roadhouse , 190m; 32.46528 oS– 123.41505 oE ± 110m, 14.xii.2012, M.V., Oswald, Diehl & Machado, Oswald #602 (1♂, 1♀, TAMU, in ETOH); 5 km S of Goongarrie, 30.05S– 121.09E, 15.xi.1970, Upton & Feehan (1♀, ANIC, in ETOH); Swan View: Talbot Road Nature Reserve , 50m; 31.87351 oS– 116.04483 oE ± 180m, 16.xii.2012, M.V., Oswald, Diehl & Machado, Oswald #604 (1♂, TAMU, in ETOH); Wandoo National Park : Kent Road, 26 air km SWSW York, 270m; 31.99773 oS– 116.52801 oE ± 70m, 17.xii.2012, M.V., Oswald, Diehl & Machado, Oswald #606 (3♂, 11♀, TAMU, in ETOH) .

Comments. On the basis of general habitus R. distivenus sp. nov. is the most distinctive species of Riekoleon . This is particularly apparent in its exceptionally slender wing outlines (which helps explain the distal origin of its first RP forks) and its elongate pronotum. However, R. distivenus contains the diagnostic characters of the genus, e.g., male ectoproct straight ventrally, male mediuncus absent, and female posterior gonapophysis very broad and bearing numerous cavisetae apically. For its phylogenetic position, see Comments for Riekoleon .

Figures

FIGURE 153. Distribution of Riekoleon species (part).

FIGURE 154. Riekoleon distivenus sp. nov.: a) head, anterior; b) head and thorax, dorsal; c) wings, dorsal.

FIGURE 155. Riekoleon distivenus sp. nov.: male: a) terminalia, lateral; b) genitalia, lateral; c) genitalia, posterior; female: d) terminalia, lateral; e) terminalia, ventral. Scale bars = 0.5 mm.