Rhyparus sulawesiensis, Minkina & Jákl & Bezděk, 2023

Rhyparus sulawesiensis View in CoL sp. nov.

( Fig. 1 -5, 7 & 10)

ZooBank:https://zoobank.org/ F95F5D84-32B6-4BA1-A0E0-F7BC6F2FF053

Holotype, ♀, « Indonesia, C-Sulawesi, Poso , 11 -16.iv.1999, 1 - 400 m., 5 -10 km SW Tambarana, Bečvář & Zábranský leg. » ( SJCP).

Paratypes, 2 ♀ & 1 ♂, same data as for the holotype (1 ♂ & 1♀ in ŁMCP; 1 ♀ in IECA) .

Type locality. – Indonesia, Sulawesi Island, C-Sulawesi, Poso, 5 - 10 km SW Tambarana.

Description of the holotype

Dorsum ( Fig. 1). – Length: 6.8 mm; maximum width: 2.2 mm. Body medium-large sized for members of this genus, elongate, not so distinctly convex, flattened in central part; almost matt; 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. 4). – Matt, tops of costae distinctly shiny; transversely subhexagonal; clypeus trapezoidal in outline, anteriorly truncate, 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 deep groove; convexity with a pair of indistinct, moderately convex ridges; nearly on whole surface with distinct, fine punctures bearing small macrosetae. Frons with four distinct, longitudinal ridges with similar structure to the ridges on the clypeal convexity. Head covered by fairly regularly spaced, moderately dense, medium sized punctures bearing small macrosetae.

Pronotum. – Matt, tops of costae distinctly shiny; with eight distinct costae and seven intercostae, with two lateral, rounded lobes on each side. Anterior lobes somewhat lower and distinctly narrower than posterior, on the top are the widest part of pronotum. Sinuation between anterior and posterior lobe weak. Costae of middle, third and fourth pair not interrupted in basal part apical half, very gently convergent, distinctly convergent in the middle of apical third; second pair of costae distinctly interrupted in basal part of apical half; costae on each side with very small punctures bearing very small macrosetae. All intercostae in anterior part without additional short costae. Median intercostae with dense punctures, quite distinctly concentrated around median part, all intercostae in basal part with distinct, dense punctation.

Scutellum . – Almost imperceptible.

Elytra. – Matt, tops of costae and preapical glandular area more distinctly shiny. Each elytron with six elevated costae, and five flat intercostae. Costae on sides with very small punctures bearing very small macrosetae. Preapical glandular area relatively small. First to fourth intercostae with two distinct rows of punctures and with one row of quite irregularly spaced, very fine punctures between that two rows; on third intercostae there is a very short additional costa with two very short additional rows of punctures. Fifth intercosta with one row of punctures; in the basal part of the fourth intercosta there is a region with an extremely 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, visible as transversely rounded bulb.

Pygidium (Fig. 5). – With very sparse, irregularly spaced punctation, with weak longitudinal rib in the middle and deep excisionon on its sides; with apex in the shape of volcano with rounded top.

Venter ( Fig. 2). – Matt. Meso-metaventral plate flattened in the middle, with distinct, narrow, quite deep longitudinal furrow; punctation of meso-metaventral plate dense, quite regularly spaced, irregular in size; all punctures bearing short macrosetae. Abdominal ventrites matt, on sides with rows of punctures; with an additional punctured furrow in basal part. Last abdominal ventrite with dense punctures, which are about one and half times larger than on last but one ventrite; in basal half in the middle part with very deep cavity that does not take the shape of the rows; in apical part in the middle with very deep groove, clearly located far below apex of pygidium. Meso- and metafemora with one very indistinct tubercle on lower border;all femora shiny, with regular, very distinct, rather small, very dense punctation; all punctures bearing small macrosetae.

Sexual dimorphism. – Males differ from females in the following characters: metatibiae more sinuate and bearing large, flattened, inwardly bent apical spine, last abdominal ventrite and pygidium normally developed.

Variability. – Body length varies from 6.3 to 6.8 mm. Intercostae are relatively more or less weakly shiny. Punctation of clypeus and pronotum is more or less variable in size, distribution and density. Median row of punctures on third elytral intercosta very weakly variable in length. The aedeagus of the male was not examined due to the very high similarity of the copulatory apparatuses in males and therefore of no value when identifying species of the genus.

Etymology. – Toponymic; an adjective derived from the name of Sulawesi Island, where the new species was collected.

Differential diagnosis. – Based on the proportions of the body (mostly large species, much less frequently medium-sized species; all species distinctly elongate), the very weakly developed lateral lobes of the pronotum, the distinctly punctate basal half of the pronotum, and the weakly developed caudal bulbs without separation between the individual bulbs, we can classify the males and females of R. sulawesiensis sp. nov. as members of a group with modified pygidium and last abdominal ventrite in females. The modified abdominal ventrites of the females make them unique and easily distinguishable from all other species known in the world. The shape of the pygidium in the females of R. sulawesiensis sp. nov. is largely similar to that of R. sepikensis . However, it is easily distinguished from the latter by the much denser and thicker body punctures (compare

Faunitaxys, 11 (66), 2023: 1 – 5. 3

4 5

1. Dorsal view. 2. Ventral view. 3. Lateral view. 4. Head. 5. Pygidium. (scale lines: 1.0 mm)

6. Rhyparus paraphilippinensis Ochi & Kakizoe, 2021 , ♀, pronotum. 7. Rhyparus sulawesiensis sp. nov., ♀, holotype, pronotum. 8. Rhyparus sepikensis Stebnicka, 1998 , ♀, paratype, pronotum. 9. Rhyparus paraphilippinensis Ochi & Kakizoe, 2021 , ♀, pygidium. 10. Rhyparus sulawesiensis sp. nov., ♀, holotype, elytral disc. 11. Rhyparus sepikensis Stebnicka, 1998 , ♀, paratype, elytral disc. (scale lines: 0.5 mm)