Pseudotelegeusis howdeni Wittmer, 1976

Pseudotelegeusis howdeni Wittmer, 1976 ( Fig. 2B, D View FIGURE 2 ):

BRAZIL, Amazonas, Manaus ( ZF-02—trilha do Igarapé, em frente ao alojamento ), 14–19.x.2023, 2.59844°S 60.207885°W, malaise, M.A. Ulysséa col. ( 1 ♂, MZSP 68682 ); GoogleMaps Novo Aripuanã, 13–17.xi.2022, 05°35'12"S 59°32'36"W, E. Lucena col. ( 1 ♂, CEMT). GoogleMaps

The biology and habits of Telegeusinae species remain unknown. Males are often collected at light or with flightinterception traps, whereas their immature stages and females remain undescribed. Females are hypothesised to be larviform or flightless ( Lawrence 2010).

The new Brazilian records considerably extend the known distribution of Pseudotelegeusis howdeni by approximately 1,000 km into central Amazonia and that of P. meloi by over 2,100 km into eastern Amazonia , suggesting that these species occupy a much larger portion of the biome than previously thought. Additional populations will probably be discovered within this range. The P. howdeni specimens we examined from Nova Aripuanã and Manaus show slight variation in size, with body lengths of 4.0 and 4.4 mm respectively, compared with 4.5–5 mm in the type series (Wittmer 1976). The specimen from Nova Aripuanã is dark brown, resembling the type series, whereas the specimen from Manaus is black. The specimen illustrated by Constantin (2010) from French Guiana is dark brown and small (4.0 mm), indicating that the Brazilian specimens fall within the recorded variation of the species.

The description of P. meloi already highlighted a considerable variation among populations from Peru, including differences in body, eyes, vertex, pronotum and elytra dimensions ( Roza et al. 2019). Our specimens from Acre have a short body length (ca. 3.5 mm) and elytra (ca. 1.3 mm), and are geographically closer to the Peruvian populations with larger bodies (e.g., Madre de Dios) than to those with smaller sizes (e.g., Panguana). This suggests that the species’ variability may not be geographically structured and could instead reflect low sampling effort.

The specimens of P. meloi from Rondônia State are generally larger (up to 4.8 mm body length), with distinctly transverse pronotum, and smaller, less protruding eyes. Their vertex occupies about two-thirds of the head, instead of the usual three-fifths. This variation falls outside the previously described range for the species, and might indicate an undescribed species. However, as P. meloi is a highly variable species, broader comparisons with specimens examined by Roza et al. (2019), together with dissections of genitalia and additional sampling from nearby areas in Rondônia and other Brazilian states, are necessary to resolve this issue. For now, it is prudent to retain this population under P. meloi until further material becomes available.

Male Telegeusinae are considered rare in collections. The specimens reported here had been deposited for several years in Brazilian collections (MZSP—Museu de Zoologia da Universidade de São Paulo, São Paulo; and CEMT—Coleção Entomológica de Mato Grosso, Cuiabá) awaiting proper identification. They were often misidentified or overlooked among representatives of other soft-bodied beetle families such as phengodids or short-elytra cantharids. A similar pattern of under-recognition also affected the soft-bodied Jurasaidae Rosa , Costa, Kramp & Kundrata ( Rosa et al. 2020), with new species continuously being recognised and described once their diagnoses became acknowledged by coleopterists (e.g., Biffi et al. 2021, Roza 2021, Nunes et al. 2023). We hope this work will stimulate a comparable process within Brazilian Omethidae taxonomy.

This first official report of Omethidae in Brazil represents an important step towards understanding the group’s diversity in the country.It should encourage the re-examination of unsorted Telegeusinae specimens in Brazilian collections, which may reveal new populations, extend the group’s known distribution, and potentially uncover undescribed species. Accurate locality data will also facilitate targeted fieldwork and expeditions aimed at clarifying their still-enigmatic natural history.