Argelodes, Ruta, 2021

Ruta, Rafał, 2021, Three new genera of large marsh beetles (Coleoptera: Scirtidae) from Valdivian temperate rain forests of southern South America, Zootaxa 5048 (4), pp. 451-485 : 452-454

Genus Argelodes gen. nov.

( Figs 1A–B , 2A , 3 , 4A , 5 )

Type species: Argelodes magnificus sp. nov., by present designation.

Diagnosis. Large (TL 9.6 mm), not saltatorial, elongate, with long legs, elytra subglabrous, covered with very short and sparse setae, setae on elytra shorter than distance between two closest punctures. Subantennal grooves moderately deep, subgenal ridge without buttonhole configuration, eyes moderately protuberant. Pronotum small, distinctly narrower than basal portion of elytra; anterolateral pronotal angles acute, distinctly protruding anteriorly. Parameroids bifid, trigonium deeply divided; apices of parameres curved and hooked.

Description. Male. Body ( Fig. 1A ) elongate, TL 9.6 mm, moderately convex. Body brown, head and pronotum covered with long, yellowish setae, elytra covered with sparse and very short setae, shorter than distance between two closest elytral punctures. Head and pronotum covered with sparse and shallow punctures and regular, polygonal microsculpture; elytra with larger, uniform punctures, separated by 1.5–2.0× diameter of a puncture, without microsculpture, punctation irregular.

Head ( Fig. 1B ) relatively small, wider than long; eyes large and strongly protuberant, finely facetted; tempora moderately long, distance from posterior margin of eye to occipital ridge ca. 0.5× diameter of the eye, slightly converging basally; distance from ventral margin of eye to subgenal ridge ca. 0.4× diameter of the eye; supraantennal ridges slightly elevated, joined to margins of eyes; subtriangular area behind eyes devoid of setation, covered with microreticulation only; frons almost flat, with two shallow depressions behind antennal insertions; subantennal grooves slightly concave, moderately deep, glossy and impunctate, each subantennal groove separated from frons by a short ridge subparallel to supraantennal ridge, continued along margin of eye as sharp ridge, in lower portion connected with subgenal ridge. Frontoclypeal suture absent; clypeus subtrapezoidal, ca. 2.6× wider than long, with straight anterior margin, lateral margins slightly converging posteriorly. Anteclypeus present, ca. 4× shorter than clypeus. Ventral portion of head ( Fig. 2A ) between subgenal ridges concave, gular area convex, rectangular, slightly longer than wide. Subgenal ridge well marked, without buttonhole configuration. Antennae filiform, antennomeres 6–11 missing in the only known specimen; antennomere 1 widest, subcylindrical, with subtle ridge marked on apical half of anterior margin; antennomere 2 subglobular and small, distinctly narrower and ca. 2× shorter than antennomere 1; antennomere 3 very long and narrow, ca. 1.8× longer than antennomere 1, slightly widening apically; antennomeres 4–5 similar to antennomere 3. Labrum covered with long setae, transverse, ca. 2.0× wider than long, anterior margin slightly emarginated, anterolateral angles rounded. Mandibles ( Fig. 3A ) symmetrical, ca. 2.3× longer than width at bases, abruptly curved in apical 1/4, apices unidentate, outer margin covered with setae; inner margin of mandibles with big subtriangular denticle and two smaller ones; molar region covered with poorly visible microsetae. Maxillary palpi ( Fig. 3C ): palpomere 1 shortest, subconical, palpomere 2 longest, ca. 3× longer than palpomere 1, palpomere 3 shorter than 2, palpomere 4 fusiform, shorter than 3 and ca. 2× shorter than 2. Galea ( Fig. 3D ) with subparallel sides, much shorter than lacinia, with long fringe of irregularly arranged setae at apex; lacinia with straight or slightly curved setae on inner margin and stronger, hooked setae on apex. Mentum ( Fig. 3B ) slightly transverse (W/L = 1.4), subtrapezoidal. Prementum subtriangular, strongly widening apically, apical margin straight, ligula covered with dense setae. Labial palpomeres: palpomere 1 long, narrow, ca. 2.5× longer than wide, sparsely covered with setae; palpomere 2 wider, subconical, ca. 1.7× longer than palpomere 1, covered with long setae; apical palpomere arising from apex of preapical one, narrow, slightly longer than palpomere 1, covered with setae.

Pronotum ( Fig. 1B ) transverse, distinctly narrower than base of elytra, ca. 1.7× wider than long; lateral carinae almost straight, subtly curved in anterior portion; disc moderately convex; anterior margin rounded; anterolateral angles subtriangular, projecting; posterior angles obtuse; base curved, with distinct margination. Prosternum reduced anteriorly; prosternal process narrow, lanceolate, posterior apex pointed, ca. 3.0× longer than wide, covered with setae.

Scutellar shield equilaterally triangular, with slightly curved lateral sides, flat, with pointed apex; anterior margin straight, impunctate, covered with microsculpture similar to that on pronotum. Elytra elongated, distinctly wider at base than pronotal base; humeri marked, apices regularly rounded. Epipleura wide at base, slightly narrower than metanepisternum, distinctly narrowed behind metaventrite, present till apices.

Hind wings ( Fig. 4A ) ca. 2.3× longer than its width; radial cell subtriangular; apical portion of r3 well visible, straight; rp-mp2 arcuate, forming acute angle with MP 1+2; MP 4 long, oblique, joining MP 3 and CuA+AA 1+2; anal field with well marked AP 3 and AP 4. Medial field with 3 free veins; pigmented areas in radial cell, radial, central and apical fields.

Mesoventrite ( Fig. 2A ) small; anterior margin with coxal rests; mesoventral process with well marked longitudinal suture; anterior portion forming deep, subtriangular fossa for reception of prosternal process; mesoventral process ca. 2× longer than wide, sides subparallel, apex bilobed, touching metaventrite; mesocoxae completely separated; mesanepisternum rhomboidal, without setation, wider than long, forming coxal rest for procoxa; mesepimeron smaller, setose, subtriangular, strongly narrowed mesally; mesocoxae subconical, slightly projecting.

Metaventrite ( Fig. 2A ) relatively short, strongly transverse (W/L 3.4), convex; discrimen complete; metanepisternum subtrapezoidal, ca. 2× longer than its width, slightly narrowing posteriorly. Metacoxae moderately large, strongly oblique, 2.7× wider than long, extending laterally to epipleura; metacoxal plate obliquely narrowing.

Legs long; femora extending beyond elytral margin, trochanters moderately long; trochantero-femoral joint oblique; metafemora longer than metatibiae, metatibiae slightly curved. Tibiae narrow, slightly widening towards apices, with paired carinae; metatibiae slightly sinuate; length of metatibial spurs equal largest width of metatibiae; mesotarsi only slightly shorter than mesotibiae [protarsi and metatarsi incomplete in the only known specimen]; tarsomere 1 elongated, sides subparallel, as long as tarsomeres 2–3 combined; tarsomere 4 emarginated at apex; apical tarsomere as long as tarsomeres 3–4 combined, with simple claws.

Abdomen ca. 1.4× longer than its width, convex; ventrites 1–4 of subequal length; ventrite 5 slightly longer, regularly rounded at apex. Abdominal ventrites regularly covered with setae. Genitalia ( Fig. 5 ) of Microcara type (sensu: Zwick 2015), symmetrical, penis large, dorsoventrally flattened, trigonium bifid, parameroids moderately wide, bifid in apical portions, longer than trigonium. Tegmen large, parameres wide at bases, narrowed and hooked in apical portion, all terminal segments are present.Female. Unknown.

Biology. Unknown.

Etymology. Combination of terra typica — Argentina and a genus name Elodes Latreille ; reference to the geographical distribution of the genus. Gender masculine.

Figures

FIGURE 1. Dorsal view. A) Argelodes magnificus sp. nov.; B) A. magnificus, close-up of head and pronotum; C) Solierodes rousseli (Solier), male; D) S. rousseli, female; E) S. rousseli, female, close-up of head and pronotum. Scale bars (A, C, D) = 3.0 mm.

FIGURE 2. Ventral view, SEM images. A) Argelodes magnificus sp. nov.; B) Solierodes rousseli (Solier).

FIGURE 3. Argelodes magnificus sp. nov., mouthparts.A) mandible, molar region enlarged; B) labium; C) maxilla; D) maxilla, galea and lacinia enlarged.

FIGURE 4. Wings.A) Argelodes magnificus sp. nov.; B) Solierodes rousseli (Solier); C) Mucronotus velutinus (Solier).Abbre- viations: AA—anterior anal vein, AP—posterior anal vein, CuA—anterior cubital vein, CuA+AA1+2—fusion of anterior cubital and anterior anal veins, MP—posterior medial vein, r3—third radial cross-vein, RA—anterior radial vein, rp-mp2—second radio-medial cross-vein, ScP—posterior subcostal vein.

FIGURE 5. Argelodes magnificus sp. nov., male.A) penis; B) tegmen; C) sternite VIII; D) sternite IX; E) tergite VIII; F) tergite IX. Scale bar = 0.5 mm.