Europs Wollaston, 1854

Genus Europs Wollaston, 1854 View in CoL

Type species: Europs impressicollis Wollaston, 1854: 150

Taxonomic assignment. The specimen under consideration shows the combination of characters corresponding to the family Monotomidae : body narrow-elongate; head prognathous; eyes lateral, entire; antennal insertions lateral, widely separated; antennae short, 10-segmented with distinct two segmented club (composed of antennomere 9 and fused antennomeres 10 and 11); fronto-clypeal suture absent; abdominal ventrites 1 and 5 longer than any of ventrites 2‒4 individually; elytra distinctly truncate apically, exposing at least one tergite; procoxal cavities widely closed externally; and mesocoxal cavities open. The fossil was assigned to the tribe Europini within the subfamily Monotominae based on (1) all coxae well separated; (2) procoxae rounded with hidden trochantins; (3) maxillary and labial palpi with palpomere 2 normal, i.e. not enlarged; (4) punctation on elytra not paired; (5) head without deep subantennal grooves extending behind the eyes; (6) tarsal formula 5-5- 5 in females; and (7) body shape in general and pronotum in particular not cylindrically elongate and comparatively short.

The studied inclusion is placed in the diverse and variable genus Europs based on the combination of the following characters, which distinguish the specimen from other similar genera of the tribe Europini occurring in the Recent Holarctic biogeographic region: (1) antennal club 2-segmented, composed of antennomere 9 and fused antennomeres 10 and 11 (club 1-segmented, composed of fused antennomeres 10 and 11 in Leptipsius Casey, 1916 ; Bactridium LeConte, 1861 ; Pycnotomina Casey, 1916 ; and in some species of Mimemodes Reitter, 1876 ); (2) long setation on ventrites absent (first abdominal ventrite with relatively long setae medially in Mimemodes ); (3) elytral punctation arranged in regular longitudinal rows (irregular elytral punctation in Phyconomus LeConte, 1861 ); (4) inflexed part of elytron with three rows of punctures (four rows of punctures in Hesperobaenus LeConte, 1861 ); (5) subquadrate pronotum (elongate pronotum in Macreurops Casey, 1916 ); (6) shortly and distinctly setose dorsum (dorsal setation long in Rhizophagoides Nakane et Hisamatsu, 1963 ); and (7) antennomere 9 about as wide as antennomere 10 (antennomere 9 narrower than antennomere 10 in Rhizophagoides and some Hesperobaenus ). Pronotal disc with impunctate median zone, short temples, abdominal ventrite 1 with femoral lines triangularly produced, and finely crenulate pronotal lateral margins are not unique for the heterogenous genus Europs and are considered species-specific characters within the genus.