Rhyparus stebnickae, Minkina & Anichtchenko & Vasiljeva & Skelley, 2022

Minkina, Ÿukasz, Anichtchenko, Alexander, Vasiljeva, Anastasija & Skelley, Paul E., 2022, Four new species of the genus Rhyparus Westwood, 1845 (Coleoptera: Scarabaeidae: Aphodiinae) with modified pygidium and last abdominal ventrite in females, Baltic Journal of Coleopterology 22 (1), pp. 81-101 : 88-90

Rhyparus stebnickae sp. nov.

( Figs. 10–12 , 23 , 29 )

Type locality. Indonesia, West Papua prov., Arfak Mts, Manokwari distr., Dueibei env., cca 20 km S of Warmare, 1190m .

Type material. Holotype (): Indonesia, West Papua prov. | Arfak Mts, 1190m alt. | Dueibei env., 10.ii­28.ii.2008 | cca 20 km S of Warmare | Manokwari distr, St. Jakl lgt. || ( Ÿ MCN). Paratypes (10exx.): 1ex.: Coll. I.R.Sc.N.B. | Papua New Guinea | Wau, Morobe prob., | Wau Ecology Institute, | 1200 m, at light | I.G.: 26373 | 18.vi.1981 | leg. J. Van Goethem || ( DUBC); 1ex.: Coll.R.Isc.N.B. | Canopy mission P.N.G. | Madang province | Batteta 19­ vi­1993 | light M1 | leg. Olivier Missa || ( DUBC); 2ex.: Papua New Guinea: | Morobe Prov.: Wau; | 21.ii.1982 || light trap | R.T.Bell, Coll. || (1ex. CNCW; 1ex. NHNG); 1ex.: Papua Nlle Guinée | Morobe i.(19)80 | env de Gurakor | W.G.Ullrich || ( ISEA); 1ex.: New Guinea: (NE) | Wau, Morobe distr. | 1200m, 2­ 10.xi.(19)61 || J. & M. Sedlacek | M.V. light trap || H.F. Howden, 1992 || ( Ÿ MCN); 3exx.: Papua New Guinea | Wau, 4000 ft. | 24­ 30.VI.1974 | H.F. Howden || Rhyparus | striatus Ar. | dt. Stebnicka (2exx. CMNC; 1ex. FSCA); 1ex.: Papua – N. Guinea | Mainyanda i.1980 | 25km W Bulolo | W.G. Ullrich 600m || ( ISEA).

Description of the holotype. Dorsum ( Fig. 10 ). Length: 6.5 mm; maximum width: 1.9 mm. Body moderate­ to large­sized for members of this genus, elongate, not so distinctly convex, flattened in central part; shiny; apparently almost glabrous, though partly clothed with very small yellowish macrosetae on head and all longitudinal costae on pronotum and elytra. Brownish to dark brown; antennae, tarsomeres and mouth parts pale brown.

Head ( Fig. 23 ) shiny; transversely sub­hexagonal; clypeus trapezoidal in outline, anteriorly weakly sinuate, on sides weakly upturned as obtuse, quite distinct tooth, and later sinuous on either side; genae distinctly more excavate than eyes; clypeal disc distinctly convex, ringed by a deep groove; convexity with a pair of very indistinct, very short, convergent ridges, nearly on whole surface with distinct, fine punctures bearing small macrosetae. Frons with four distinct, longitudinal ridges with similar structure as ridges on clypeal convexity. Head covered by quite regularly spaced, quite dense, moderately large punctures bearing small macrosetae.

Pronotum shiny; with eight low but distinct costae and seven intercostae, with two lateral, rounded lobes on each side.Anterior lobes somewhat lower and distinctly narrower than posterior; posterior lobes on the top are the widest part of pronotum. Costae of third and fourth pair not interrupted in basal part of apical half, very gently convergent,

Minkina Ł., Anichtchenko A., Vasiljeva A., Skelley P.E.

distinctly convergent in the middle of apical third; median pair of costae in apical half become very low but without any cutpoint of interruption; second pair of costae distinctly interrupted in basal part of apical half; costae on each side with small punctures bearing very small macrosetae.All intercostae in anterior part without additional short costae. Median intercostae with dense punctures, very distinctly concentrated around median part, all intercostae in basal part with distinct, dense punctation.

Scutellum almost imperceptible.

Elytra shiny. Each elytron with six elevated but flattened on the top costae, and five flat intercostae. Costae on sides with very small punctures bearing very small macrosetae. Preapical glandular area relatively small. Intercostae first to fourth with two distinct rows of punctures; on third intercostae there is short additional costae with additional row of punctures untill half of length of elytra. Fifth intercosta with one row of punctures; in basal part of fourth intercosta there is region with extremely short additional costa, with some additional punctures here. External caudal bulb distinctly reduced, area between external caudal bulb and sides of elytra not divided; external and medio­internal caudal bulbs not divided; medio­internal caudal bulb shortened, transverse, internally stretched.

Pygidium ( Fig. 29 ) with dense, irregularly spaced punctation, with very distinct longitudinal rib in the middle and deep excision on its sides; with distinctly longitudinal apex in the shape of volcano with sinuate top.

Venter ( Fig. 11 ) shiny. Meso­metaventral plate flattened in the middle, with distinct, narrow, quite deep longitudinal furrow; punctation of meso­metaventral plate dense, regularly spaced, irregular in size; all punctures bearing short macrosetae. Abdominal ventrites moderately shiny, on sides with rows of punctures; with an additional punctured furrow in basal part. Last abdominal ventrite with dense punctures, which are slightly larger than on last but one ventrite; in basal half in the middle part with dense, very deep, longitudinal rows; in apical part in the middle with very deep groove, clearly located much below apex of pygidium.

Mesofemora with two distinct tubercles on lower border; metafemora with very weak tubercles on lower border; all femora shiny, with regular, very distinct, rather small, very dense punctation; all punctures bearing small macrosetae.

Variation. Length of body: 6.2­ 7.0 mm. Intercostae of pronotum and elytra usually are shiny, but sometimes may be somewhat less shiny. Lateral lobes of pronotum may be more or less weakly developed. Density of punctation of pronotal and elytral intercostae is quite distinctly variable. Degree of concentration of punctures in median intercostae of pronotum is very weakly variable. Usually elytral costae are flattened and wide, rarely may be somewhat more distinctly convex and quite narrow. Additional rows of fine punctures observed usually on third elytral intercostae – between main rows, but there are specimens with simple punctures on all rows.

Sexual dimorphism. Shape of meso­metaventral plate (in both sexes), apex of mesotibiae (in both sexes) and shape of last abdominal ventrite and pygidium of males are typical for sexual dimorphism in genus Rhyparus . Last abdominal ventrite and pygidium of females is distinctly elongate at apex ( Fig. 29 ). Last abdominal ventrite and pygidium of males are not modified.

Etymology. Patronymic. Dedicated to Zdzis˘awa Stebnicka who noticed unusual sexual dimorphism in the genus Rhyparus at the first time.

Affinity. See discussion and tables 1 and 2. Additional problem is that some specimens of R. gracilis Arrow, 1905 (which them R. stebnickae sp. nov. was collected on the same localities on Papua New Guinea) may have similar structure of elytral costae, identique structure of caudal bulbs and somewhat similar shape of lateral lobes of pronotum (posterior lateral lobes can be widely, regularly rounded, weakly developed, with very small sinuation between them and anterior lateral lobes). Anyway females of R. gracilis have normally developed pygidium and last abdominal ventrite. Males of R. gracilis can be distinguished by: more distinctly convex body, posterior lateral lobes of pronotum never more distinctly developed than anterior, punctures in median intercostae of pronotum never so distinctly concentrated nearby the middle (never create so distinct longitudinal line) and elytral intercostae usually matt.

Figures

Figs. 10–12. Rhyparus stebnickae sp. nov.,, holotype: 10 – dorsal view; 11 – ventral view; 12 – lateral view. Scale lines: 1.0 mm.

Figs. 20–25. Heads: 20 – R. bacanensis sp. nov.,, holotype; 21 – R. buruensis sp. nov.,, holotype; 22 – R. fijiensis sp. nov.,, holotype; 23 – R. stebnickae sp. nov.,, holotype; 24 – R. paraphilippinensis Ochi & Kakizoe, 2021,; 25 – R. sepikensis Stebnicka, 1998,, paratype. Scale lines: 1.0 mm.

Figs. 26–33.Abdominal apexes with black­white miniatures of pygidium on left­down side: 26 – R. bacanensis sp. nov.,, holotype; 27 – R. buruensis sp. nov.,, holotype; 28 – R. fijiensis sp. nov.,, holotype; 29 – R. stebnickae sp. nov.,, holotype; 30 – R. approximans Fairmaire, 1893,; 31 – R. loebli Paulian, 1983,; 32 – R. paraphilippinensis Ochi & Kakizoe, 2021,; 33 – R. sepikensis Stebnicka, 1998,, paratype. Scale lines: 0.5 mm.