Antecessorirhyparus Minkina, 2020

Antecessorirhyparus Minkina, 2020 View in CoL

Antecessorirhyparus Minkina, 2020a: 37 View in CoL . Type species Rhyparus octovirgatus Schmidt, 1916 View in CoL , by original designation.

Diagnosis. Antecessorirhyparus is distinguished from other genera of Rhyparini by the combination of the following: Body elongate, parallel sided; length 3.4–5.0 mm. Pronotal lateral margin sinuate, anterior and intermediate lobes weak; costae low. Elytral costal intervals convex, elytral costae only weakly higher than intervals; discomedial costa with postcostal bulb bearing a dorsal tuft of setae; with caudal bulb entire (not deeply notch dorsally in caudal view). Metaventrite lacking lateral depressions on disc. Abdominal ventrite 2–5 strongly crenate along broad anterior groove; with large triangular fovea on each side.

Comments. Prior to this work, Antecessorirhyparus contained two species: A. octovirgatus ( Schmidt, 1916) from Fiji ( Minkina 2020a), and A. papuanus Minkina & Jákl, 2024 , that was recently described from Papua New Guinea ( Minkina & Jákl 2024). With the new species described here, we can better define the generic limits of Antecessorirhyparus . The diagnosis above lists characters shared between A. octovirgatus and A. samoaensis , new species. However, several of these characters are not shared with A. papuanus , whose character states are shared with some species of Rhyparus . Based on this refined generic definition, A. papuanus is here transferred to the genus Rhyparus , becoming Rhyparus papuanus ( Minkina & Jákl, 2024) , new combination. However, R. papuanus remains an unusual species whose affinities within the broadly defined genus Rhyparus remain unclear. In several characters (larger body size, abdominal ventrites having smooth and narrow anterior furrow, abdominal ventrites lacking lateral fossae, dense pronotal punctation, low elytral costae, etc.), R. papuanus is similar to species with a modified female pygidium ( Minkina et al. 2022, 2023, 2025). A female of this species may help resolve its relationships.

As discussed by Minkina (2020a), A. octovirgatus and now A. samoaensis , new species, share some characters with Leptorhyparus Howden, 2003 ( Howden 2003; Minkina 2020b; Skelley 2021), and Lioglyptoxenus Pittino, 2006 ( Pittino 2006). While some characters (abdominal ventrite crenulation and lateral fossa) would indicate closer relationship to other regional taxa like R. guadalcanalensis or R. helophoroides .