Leptorhyparus Howden, 2003

Skelley, Paul E., 2021, A new species of Leptorhyparus Howden, 2003 (Coleoptera: Scarabaeidae: Aphodiinae: Rhyparini) in amber from the Dominican Republic, with comments on extant species, Insecta Mundi 2021 (892), pp. 1-7 : 2

Leptorhyparus Howden

Leptorhyparus Howden 2003: 397 . Type species: Leptorhyparus gilli Howden 2003: 400 , by original designation.

Diagnosis. Leptorhyparus is easily distinguished from other rhyparine genera in the New World by its small size (length <3.5 mm); the erect tuft of setae at the caudal apex of the discomedian costa; elytra with caudal bulb and trichome deeply divided dorsally; and apical half of pygidium with two complete parallel (not Y-shaped) carinae ( Fig. 4–5 ). Other characters include nearly parallel-sided body; pronotum with lateral margin lobed at anterior angle; pronotum and elytra with costae broadly convex (not distinctly carinate), wide ( Fig. 1–3 ); and intervals equal in width or narrower than costae.

Comment. Worldwide, Leptorhyparus is most similar to Lioglyptoxenus Pittino in most features mentioned above. They differ in ways stated in Pittino’s (2006) key to world genera, primarily by body size, pronotal shape, and distribution. Lioglyptoxenus is larger, length> 3.9 mm, lacks lobes on the pronotal lateral margin, and is found in Asia. Leptorhyparus is unique among the world’s rhyparines with the caudal bulb and trichome of the elytra split onto inner and outer lobes, and the pygidium with two nearly parallel carina the entire length. Other genera have bulbs lacking to entire, and the carina on the pygidium is absent, single, or Y-shaped.

Minkina (2020) recently reviewed Leptorhyparus describing two new species and presented a key to species. It is unfortunate there were only two unique specimens available for that study. The species are valid, but some of the key characters are variable within the series available. Minkina (2020) commented that variations in these characters could be related to body size or other variables. Some are discussed below.

Figures

Figures 1–8. Leptorhyparus characters. 1–3) Head and pronotum.1) L. brasiliensis. 2) L. gilli. 3) L. peruanus. 4–5) Elytra and pygidium, caudal view. 4) L. brasiliensis, 5) L. peruanus. 6–8) Body parts of L. brasiliensis, from French Guiana. 6) Epipharynx. 7) Male genitalia, caudal view. 8) Male genitalia, lateral view.