Steirodon (Frontinus) planifemur Gorochov, 2025

Steirodon (Frontinus) planifemur Gorochov View in CoL sp. nov.

( Figs 71–73 View Figs 58–73 , 79–82 View Figs 74–82 , 89–93 View Figs 83–105 )

Etymology. This species name consists of the Latin prefix “plani-“ (flat) and the Latin morphological term “femur” (femur) due to a characteristic structure of the fore femur dorsal surface.

Material. Holotype – male, PERU: Junin Department, Satipo Prov. , “Zona de amortiquamiento de la bosque de proteccion Pui Pui” near Alto Cuviriaki Vill., 11 º 11'06–07" S, 74 º 51'50–51" W, 1100–1200 m, 27 December 2018 – 2 January 2019, A. Gorochov ( ZIN) . Paratype – male, ECUADOR: ~ 70 km SE of Lago Agrio Town, environs of S. Pablo de Kantesiya Vill. on Rio Aguarico, lowlying forest, 10–17 November 2005, A. Gorochov, A. Ovtshinnikov ( ZIN) .

Description. Male (holotype). Body coloration yellowish (greenish in living conditions) but with brown to dark brown middle and distal portions of antennal flagellum, light brown dorsal and medial parts of scape as well as small marks on pedicel and proximal segments of flagellum ( Fig. 71 View Figs 58–73 ), rose areas on epicranium behind eyes, light greyish (with brownish tinge) dorsolateral keels of pronotum and stripes along these keels on disc and lateral lobes (these stripes fused with each other and forming rather wide longitudinal dorsolateral bands; Figs 72, 73 View Figs 58–73 ), light brown to brownish rose fore femur (having proximal two thirds of upper surface whitish; Fig. 89 View Figs 83–105 ), light brownish rose proximal third of fore tibia ( Figs 90, 91 View Figs 83–105 ), and dark brown small marks on all tibial bases in places of their articulations with femora. Lower rostral tubercle of head anteroposteriorly flattened, barely wider than apical part of upper rostral tubercle but somewhat narrower than scape (scape almost 1.3 times as wide as distal part of low- er tubercle), in front with widely rounded apical part hardly covering lowest part of upper rostral tubercle ( Fig. 71 View Figs 58–73 ); upper rostral tubercle slightly narrowing to barely widened and anteriorly flattened apical part, with dorsal surface having rather short and narrow but distinct longitudinal groove, and with dorsal edge (in profile) somewhat arcuated (convex); pronotum with almost flat (slightly concave) disc having distinctly concave anterior edge and slightly convex posterior edge, with dorsolateral keels distinct but low and practically undenticulated as well as having two small notches on each keel (anterior notch more distinct and almost angular, but posterior one very shallow and poorly distinct; Fig. 72 View Figs 58–73 ), and with lateral lobes as in Fig. 73 View Figs 58–73 ; tegmina long and rather narrow ( Fig. 79 View Figs 74–82 ), with all RS branches ending in anal tegminal edge (clearly before tegminal apex), and with stridulatory apparatus as in Figs 80–82 View Figs 74–82 (stridulatory vein in left tegmen about 3.9 mm in length and with approximately 55 ventral teeth); hind wings rather strongly protruding beyond tegminal apices; fore femur with flat (barely concave) proximal two thirds of dorsal surface and longitudinally keel-like outer and inner edges of this flat part ( Fig. 89 View Figs 83–105 ); fore tibia with spinule on outer dorsal edge near tympana, and with almost open (but somewhat immersed) outer tympanum and partly slit-like inner tympanum ( Figs 90, 91 View Figs 83–105 ); proximal halves of middle and hind tibiae barely widened (approximately as in Figs 57 View Figs 38–57 , 101 View Figs 83–105 ); abdominal apex typical of this subgenus: last tergite almost truncated posteriorly, cerci and epiproct as in Fig. 92 View Figs 83–105 , genital plate with three small lobules at apex (but median lobule clearly shorter than lateral ones) and very short (almost indistinct) styli ( Fig. 93 View Figs 83–105 ).

Variations. Male paratype with more uniform coloration, but antennal flagellum and femorotibial articulations coloured almost as in holotype, and fore femur also with whitish two thirds of dorsal surface; stridulatory vein of left tegmen with about 52 ventral teeth; genital plate with only a pair of small lobules at apex (styli indistinct).

Female unknown.

Length in mm. Body 23–24; body with wings 58– 60; pronotum 6.4–6.7; tegmina 44–45.5; hind femora 24–25.

Comparison. The new species is most similar to S. (F.) tricenarium and S. (F.) barcanti in the pronotum with practically smooth and slightly keel-like dorsolateral carinae, but it differs from them in less flattened dorsal surfaces of the fore femora and less high lateral pronotal lobes (in the new species these lobes almost as long as high, but in these congeners, they are clearly higher than long), from only S. (F.) tricenarium in the absence of dark line along proximal parts of costal tegminal edges, and from only S. (F.) barcanti in distinctly narrower rostral tubercles. The new species is also similar to S. (F.) robertsorum in the structure of the lower rostral tubercle, but it is clearly distinguished from the latter species by practically smooth (not finely denticulated) dorsolateral carinae of the pronotum, distinctly longer (narrower) tegmina (approximately 3.5 and 3.1 times as long as wide in males of the new species and of S. robertsorum , respectively), a longer stridulatory vein in the male left tegmen (about 3.9 mm; vs: nearby 3.25 mm) and less numerous ventral teeth of this vein (52–55; vs: nearby 65). From all other species of this subgenus, the new species differs in a non-bilobated apex of the lower rostral tubercle in combination with less distinctly denticulated dorsolateral pronotal keels and the absence of darkened stripes on the tegmina.