Rhyparini

Skelley, Paul E. & Minkina, Łukasz, 2025, Review of the Rhyparini (Coleoptera: Scarabaeidae: Aphodiinae) of eastern Melanesia and Polynesia, with descriptions of new species, Zootaxa 5632 (1), pp. 115-137 : 117

Key to Rhyparini genera and species of Fiji, New Caledonia, Samoa, and Vanuatu

For comparison with potentially related taxa in the broader region, this key includes species reported from the Solomon Islands ( Minkina et al. 2025). An asterisk “*” indicates species not presently known from the study region.

1 Metatibia greatly enlarged, broad, lobed or twisted ( Figs. 10 , 17 , 23 ); elytra with caudal bulb small, trichome present or not; Fiji................................................................................................ 2

- Metatibia narrow entire length, flattened, not enlarged or modified; elytra with caudal bulb large, trichome present and distinct; widespread.......................................................................................... 4

2 Body length> 4 mm; pronotum with posterior medial surfaces of intercostae bearing numerous large setae; elytron with caudal bulb reduced to small tubercle, not projecting, with patches of setae at apical end of discomedian costa, lacking trichome ( Fig. 20 )................................................................... Hadrorhyparus pecki Howden, 1995

- Body length <4 mm; pronotum with posterior medial surfaces of intercostae appearing glabrous; elytron with caudal bulb present, projecting upward, trichome present or not.......................................................... 3

3 Pronotal lateral margin sinuate, nearly straight, not lobed ( Fig. 23 ); elytra with small punctures at base of intercostae; with caudal trichome structure present, but not strongly setose ( Fig. 27 ); metatibia strongly sinuate and lobed....................................................................... Hadrorhyparus vitiensis Skelley & Minkina , new species

- Pronotal lateral margin with deep emargination between distinct anterior and median lobes ( Fig. 10 ); elytra with large, deep punctures at base of intercostae; with caudal trichome reduced, apparently absent ( Fig. 14 ); metatibia appearing twisted, somewhat sinuate, not lobed.................................... Hadrorhyparus fijiensis ( Howden & Storey, 2000)

4 Elytra with intervals between costa raised, glossy, only slightly less prominent than alternating costae ( Figs. 1 , 5 )........ 5

- Elytra with intervals between costa flattened, dulled, distinctly different than alternating costae ( Figs. 28, 30, 32 , 34 , 40 )... 6

5 Pronotum with paramedian costae not distinctly convergent anteriorly; median costal interval with minute punctures only; all costal intervals flattened posteriorly ( Figs. 1, 4 ); Fiji................. Antecessorirhyparus octovirgatus ( Schmidt, 1916)

- Pronotum with paramedian costae distinctly converged in anterior third; median interval with numerous large punctures and two distinct pits at basal third; lateral costal intervals convex posteriorly, almost appearing as short costae ( Figs. 5, 8 ); Samoa............................................... Antecessorirhyparus samoaensis Skelley & Minkina , new species

6 Body length <5.5 mm (most <5mm); abdominal ventrites 2–3 distinctly crenate along anterior margin ( Fig. 31 )......... 7

- Body length> 6 mm; abdominal ventrites 2–3 smooth along anterior margin ( Figs. 35 , 41 ).......................... 8

7 Pronotum with posterior third of median intercosta usually bearing some dense punctures; elytral intercostae rarely with visible setae between rows of punctures; metatibia of male with inner margin swollen at basal third then flattened or concave to apex which lacks an inner apical tooth ( Fig. 32 ); last abdominal ventrite of male with prominent median keel ( Fig. 33 ); widespread................................................................... Rhyparus helophoroides Fairmaire, 1893

- Pronotum with posterior third of median intercosta lacking punctures; elytral intercostae with macrosetae between rows of punctures; metatibia of male with inner margin regularly rounded entire length to a large inner apical tooth; last abdominal ventrite of male lacking prominent median keel (see figures in Minkina et al. 2025); Solomon Islands, eastern Papua New Guinea..................................... * Rhyparus guadalcanalensis Minkina, Skelley, Jákl, Král, & Li, 2025

8 Clypeus anterior margin on each side obtusely angled ( Fig. 37 ); elytral intercostal 3, between discolateral and posthumeral costae, lacking costal remnant and third median row of punctures (rarely with a few minute punctures ( Figs. 28 , 34 ); mesotarsus and metatarsus with ventral surface densely pilose, hiding surface; abdominal ventrites with distinct triangular fovea on each side ( Fig. 35 ); female with pygidium normal (held more perpendicular to axis of body), lacking apical process; terminal abdominal ventrite not shortened medially for pygidium...................................................... 9

- Clypeus anterior margin on each side with acute tooth ( Fig. 40 ); elytral intercosta between discolateral and posthumeral costae with a costal remnant at base ( Figs. 32 , 40 ) and a median third row of small punctures nearly to apex; mesotarsus and metatarsus with ventral surface lacking or weakly pilose, surface visible; abdominal ventrites punctate, lacking fovea on each side; female with pygidium depressed (held along longitudinal axis of body), with apical process; terminal abdominal ventrite shortened medially to receive pygidium ( Figs. 33 , 43 )............................................................... 10

9 Elytral intercostal surface rugose with two to three rows of punctures, which can be obscured by rugosity; caudal trichome small; caudal bulb with two conical, prominent lobes ( Figs. 34, 37 ); Vanuatu.............. Rhyparus rugatus Arrow, 1935

- Elytral intercostal surface smoothly flattened between two rows of punctures; caudal trichome large; caudal bulb with two rounded, less prominent lobes ( Figs. 28, 29 ); New Guinea, Solomon Islands, American Samoa................................................................................................ Rhyparus breviceps Paulian, 1984

10 Pronotum with intercostae densely punctate, punctures in posterior half separated by a diameter or more ( Fig. 30 ); elytral intercostae glossy, with opalescent sheen; median puncture row of third intercosta rarely reaching midlength; female with apex of pygidium narrowly truncate ( Fig. 31 ); Fiji........ Rhyparus fijiensis Minkina, Anichtchenko, Vasiljeva, & Skelley, 2022

- Pronotum with intercostae coarsely, densely punctate, punctures in posterior half separated by less than a diameter; elytral intercostae matt, lacking sheen; median puncture row of third intercosta surpassing midlength, often reaching apex; female with apex of pygidium acutely rounded, not truncate ( Fig. 43 ).................................................... 11

11 Elytra with gradual swelling at posterior apex of discomedial costae; juxtasutural costae in lateral view near apex more angled ventrally ( Fig. 40 ); female with anterior furrow of last ventrite distinctly narrower medially than laterally ( Fig. 43 ); Vanuatu........................................................ Rhyparus vanuatuensis Skelley & Minkina , new species

- Elytra with abrupt, bulbous swelling at posterior apex of discomedial costae; juxtasutural costa in lateral view near apex evenly rounded; female with anterior furrow of last ventrite not narrowed medially (see figures in Minkina et al. 2025); Solomon Islands.......................................... * Rhyparus malaitaensis Minkina, Skelley, Jákl, Král, & Li, 2025

Figures

FIGURES 10–16. Monteitheolus fijiensis Howden & Storey, 2000, holotype female (QMA). 10) Habitus, dorsal view; 11) habitus, ventral view; 12) habitus, lateral view. 13) Head and pronotum, oblique view; 14) elytral apex; 15) dorsal oblique habitus; 16) Labels. Photos © Queensland Museum, Geoff Thompson, used with permission. Scale lines = 0.25 mm.

FIGURES 17–22. Hadrorhyparus pecki Howden, 1995, male, Viti Levu (NZAC). 17) Habitus, dorsal view; 18) habitus, ventral view; 19) habitus, lateral view; 20) elytra and metathoracic legs, oblique lateral view. 21) male genitalia, lateral view; 22) male genitalia, caudal view. Scale lines = 1.0 mm.

FIGURES 23–27. Hadrorhyparus vitiensis Skelley & Minkina, new species, holotype male (USNM). 23) Habitus, dorsal view; 24) habitus, ventral view; 25) habitus, lateral view; 26) metathoracic legs, oblique-ventral view; 27) elytra and metathoracic legs, oblique-dorsal view. Scale lines = 1.0 mm.

FIGURES 1–4. Antecessorirhyparus octovirgatus (Schmidt, 1916) female (FSCA). 1) Habitus, dorsal view; 2) habitus, ventral view; 3) habitus, lateral view; 4) head and pronotum, dorsal oblique anterior view. Scale lines = 1.0 mm.

FIGURES 5–9. Antecessorirhyparus samoaensis Skelley & Minkina, new species, holotype female (NZAC). 5) Habitus, dorsal view; 6) habitus, ventral view; 7) habitus, lateral view; 8) head and pronotum, dorsal oblique anterior view; 9) elytral apex, dorsal oblique caudal view. Scale lines = 1.0 mm.

FIGURES 28–33. Rhyparus species. 28) Rhyparus breviceps Paulian, female from Papua New Guinea, dorsal habitus; 29) Rhyparus breviceps Paulian, female from Papua New Guinea, elytral apex, oblique-caudal view; 30) Rhyparus fijiensis Minkina, Anichtchenko, Vasiljeva, & Skelley, dorsal habitus male paratype; 31) Rhyparus fijiensis Minkina, Anichtchenko, Vasiljeva, & Skelley, abdominal ventrites female paratype; 32) Rhyparus helophoroides Fairmaire, male from New Caledonia, dorsal habitus; 33) Rhyparus helophoroides Fairmaire, male from New Caledonia, abdominal ventrites, ventral-oblique view. Scale lines = 1.0 mm.

FIGURES 34–39. Rhyparus rugatus Arrow, lectotype male (NHML). 34) Habitus, dorsal view; 35) habitus, ventral view; 36) habitus, lateral view; 37) oblique dorsal habitus; 38) genitalia, lateral view; 39) labels. Scale lines = 1.0 mm.

FIGURES 40–45. Rhyparus vanuatuensis Skelley & Minkina, new species. 40) Habitus, dorsal view, holotype female; 41) habitus, ventral view, holotype female; 42) habitus, lateral view, holotype female; 43) abdominal ventrites, holotype female; 44) male allotype genitalia, lateral view; 45) male allotype genitalia, caudal view. Scale lines = 1.0 mm.