Stereophilus Biscaccianti, Audisio & Esser, 2022

Biscaccianti, Alessandro B., Esser, Jens, Cuoco, Silvio, Grimaldi, Enrica Giuliano & Audisio, Paolo A., 2022, West Palaearctic taxa formerly connected to the ‘ old’ genus Atritomus Reitter, 1877 (Coleoptera, Mycetophagidae): taxonomy, distribution, and description of a new genus, European Journal of Taxonomy 828, pp. 61-74 : 64-65

Stereophilus Biscaccianti, Audisio & Esser gen. nov.

urn:lsid:zoobank.org:act:030718A5-DF2E-4C19-8DBC-B46FB5B1B934

Type species

Atritomus filicornis Reitter, 1887 ( Reitter 1887b) .

Diagnosis

Stereophilus Biscaccianti, Audisio & Esser gen. nov. differs from all other known mycetophagid genera chiefly in having simple, filiform antennae. To the best of our knowledge, the threadlike antennal shape of this taxon likely represents an autapomorphic character state within the family. The new genus looks more similar to Triphyllus Dejean, 1821 and Mycetophagus Fabricius, 1792 rather than to Eulagius , in possessing a comparatively larger head, a wider and more strongly transverse pronotum with maximum width just ahead of base, anterolateral angles of pronotum rounded and blunt, not projected forward, and less convex body in lateral view. The strongly reduced laterobasal pronotal impressions, the chaetotaxy, and the body shape apparently place Stereophilus gen. nov. closer to Triphyllus , from which it differs in the lack of pore fields on the male abdomen (see Lawrence et al. 2014) and in the antennal features described below. The new genus differs from Mycetophagus chiefly in having laterobasal pronotal impressions almost indistinct, punctuation only vaguely arranged in striae at the elytral base, and filiform antennae. It also strongly differs from Typhaeini Thomson, 1863 (sensu Nikitsky 1993) and Bergininae Leng, 1920 (sensu Lawrence et al. 2014) in having laterally open mesocoxal cavities. These features make Stereophilus gen. nov. impossible to confuse with Atritomus (currently a synonym of Entoxylon sensu novum), in which the type species of the new genus was originally placed, and easy to separate from Eulagius .

Etymology

The new genus is named after Stereum Hill ex Pers. , the genus name of one of the fungi known as larval host of the included species, with addition of the Latin suffix ‘- philus ’ meaning ‘lover’. The gender is masculine.

Description

A medium-sized mycetophagid, elongate, subparallel, slightly convex in lateral view, with shiny integument. Head moderately wide, about 1.3–1.5 × as wide as long (measured from anterior edge of clypeus to neck), and about 0.58–0.61 × as wide as maximum pronotal width, deeply and coarsely punctured; frontoclypeal suture straight or barely concave, slightly impressed, finely but distinctly carinate, with carina continuing on sides of the frons up to upper edge of eyes, delimiting the frons on three sides so that it appears clearly trapezoidal in shape; clypeus transverse, about twice as wide as long, lateral margins slightly converging forwards, anterior margin straight, distal two fifths of clypeus membranous; antennal insertions clearly visible from above, not concealed by the aforementioned frontal carina; compound eyes slightly vertically elongate-oval, not globose, not emarginate anteriorly, weakly protruding laterally, anterior margin of eye not forming an evident angle with gena, finely facetted with interfacetal setae longer than diameter of one eye facet.Antennae 11-segmented, long, slender, surpassing pronotal base with the last three antennomeres if stretched backward through subantennal groove, without a distinct club, not or indistinctly widened towards apex, all antennomeres distinctly longer than wide. Pronotum finely margined on all sides, transverse, as wide as or barely wider than elytral base across humeri, constricted anteriorly, with maximum width just ahead of base, sides arcuate in dorsal view, lateral margin simple or indistinctly crenate (barely visible at high magnification), anterior edge straight, anterolateral angles rounded and blunt, not projected forward, posterior edge weakly trisinuate, posterolateral angles rounded, paired basal impressions barely pronounced. Prosternal pubescent fovea absent in both sexes; notosternal suture complete. Scutellar shield subrectangular, about twice as wide as long, densely punctate. Elytra slender, about 1.7 × as long as combined maximum width, parallel sided up to distal fourth, rounded together at apex, elytral punctures weakly impressed and vaguely seriate at elytral base, then progressively confused towards apex, setation sparse, long, and semierect, background pubescence absent; epipleuron incomplete, large at base, regularly narrowed up to distal third of elytron, then obliterated. Hind wing ( Fig. 1D ) fully developed, about 2.5 × as long as wide. Mesocoxal cavities laterally open. Paired pore fields on male abdomen absent. Legs slender, tarsal formula 3-4- 4 in males, 4-4- 4 in females.

Included species

The new genus is erected for Atritomus filicornis , the only species included thus far.

Figures

Fig. 1. Stereophilus filicornis (Reitter, 1887) gen. et comb. nov., ♂ from Italy, Tuscany. A. Habitus. B. Aedeagus (dorsal view). C. Aedeagus (lateral view). D. Right hind wing of a male from France, Haute-Garonne. Scale bars: A, D = 1 mm; B–C = 0.5 mm.