Rhyparus anichtchenkoi, Minkina, 2023

Minkina, Łukasz, 2023, A new species of the genusRhyparus Westwood, 1845 (Coleoptera: Scarabaeidae: Aphodiinae) from Papua New Guinea, Baltic Journal of Coleopterology (Athens, Greece) 23 (2), pp. 209-214 : 210-213

Rhyparus anichtchenkoi sp. nov.

( Figs 1-6 )

Type locality. Papua New Guinea, Madang province, Batteta .

Type material. Holotype (♂): “ Coll. R. Isc. N.B. | Canopy mission P.N.G. | Madang province | Batteta 21.iv.1993 | Light T 2 | leg. Olivier Missa ” ( IRSN). Paratypes (8exx.): 1ex.: “the same as holotype but: “ 23.iii.1993 | Light T 2””( IRSN); 2exx.: “the same as holotype but: “ 2.vii.1996 | light AR60””( IRSN; ŁMCN); 1ex.: “the same as holotype but: “ 2.v.1996 | light AR10””( DUBC); 2exx.: “the same as holotype but: “ 22.iv.1996 | light M8””( IRSN; ŁMCN); 1ex.: “the same as holotype but: “ 15.iv.1996 | light AR9””( IRSN); 1ex.: “the same as holotype but: “ 6.vi.1996 | light AR16””( IRSN).

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Description of the holotype. Dorsum ( Fig. 1 ). Length: 6.2 mm; maximum width: 1.95 mm. Body medium-sized for members of this genus, moderately elongate, convex, shiny, apparently almost glabrous, though partly clothed with very small yellowish setae on head and all longitudinal costae on pronotum and elytra. Brownish to dark brown; antennae, tarsomeres and mouth parts pale brown.

Head ( Fig. 4 ) shiny, transversely subhexagonal, clypeus trapezoidal in outline, anteriorly very weakly sinuate, on sides weakly upturned as obtuse, weak tooth, and later sinuous on either side; genae distinctly more excavate than eyes; clypeal disc distinctly convex, ringed by a not so deep groove; convexity with a pair of quite distinct, very short, convergent ridges, nearly on whole surface with distinct, moderately coarse punctures bearing small setae. 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 setae.

Pronotum shiny, tops of costae distinctly shiny; with eight distinct costae and seven intercostae, with two lateral, rounded lobes on each side. Anterior and posteror lobes with similar high, anterior lobe somewhat narrower than posterior. Costae of middle, third and fourth pair not interrupted in basal part of apical half, very distinctly convergent in the middle; second pair of costae very distinctly and widely interrupted in the middle; costae on each side with very small punctures bearing very small setae. All intercostae in anterior part without additional short costae. Median intercostae with dense punctures, very distinctly concentrated around median part into longitudinal line, all intercostae in basal part with distinct, dense punctation.

Scutellum almost imperceptible.

Elytra shiny. Each elytron with six elevated costae, and five flat intercostae. Costae on sides with very small punctures bearing very small setae. Preapical glandular area relatively small. Intercostae first, second and fourth with two distinct rows of punctures; third intercostae with three indistinct rows of punctures; additionally, on third intercostae there is very short additional costae with very short additional rows of punctures on its sides. Fifth intercosta with one row of punctures; in basal part of fourth intercosta there is region with extremally short additional costa, with some additional punctures. 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, transversally rounded, internally stretched.

Pygidium with dense, irregularly spaced punctation, with weak longitudinal rib in the middle and deep excisionon its sides. Normaly developed.

Venter ( Fig. 2 ) moderately shiny. Mesometaventral plate flattened in the middle, with distinct, narrow, quite deep longitudinal furrow; punctation of mesometaventral plate dense, quite regularly spaced, irregular in size; all punctures bearing short setae. Abdominal ventrites moderately shiny, very densely and coarsely punctate. Last abdominal ventrite normaly developed, with dense punctures, which are very coarse nearby its base; in the middle with longitudinal rib.

Meso- and metafemora without tubercles on lower border; all femora shiny, with regular, very distinct, rather fine, very dense punctation; all punctures bearing small setae.

Aedeagus ( Fig. 6 ) elongate, with parameres very short, with phallobase distinctly elongate, relatively weakly curved.

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Variation. Total body length 6.1 mm – 6.8 mm. Punctation of pronotum can be more or less dense. Second pair of costae of pronotum more or less distinctly shortened basally. Median row of punctures on third intercostae of elytra may be more or less distinctly developed.

Sexual dimorphism. Typical for the members of the genus. Pygidium and last abdominal ventrite of male as in fig. 2. Pygidium and last abdominal ventrite of female not modified, as in fig. 5.

Etymology. I dedicate the name of the new species to Alexander Anichtchenko – entomologist, Carabidae specialist, friend who organized material for me with specimens of undescribed species.

Affinity. The newly described species appears to be intermediate between Rhyparus gracilis Arrow, 1905 and R. mokaiensis Stebnicka, 1998 . R. gracilis is one of the most variable species within the genus and for this reason differentiating features are compared in detail in the table below.

Figures

Figs 1-3.Rhyparus anichtchenkoi sp. nov., ♂, holotype: 1- dorsal view; 2- ventral view; 3- lateral view. Scale lines: 1.0 mm.

Figs 4-6.Rhyparus anichtchenkoisp. nov.: 4- head, ♂, holotype; 5- last abdominal ventrite and pygidium, ♀, paratype; 6- aedeagus, holotype. Scale lines: 1.0 mm.