Eronyxa Reitter, 1876

Kolibac, Jiri, 2013, Trogossitidae: A review of the beetle family, with a catalogue and keys, ZooKeys 366, pp. 1-194 : 123-125

Genus Eronyxa Reitter, 1876 Fig. 10 ; Map 11 , 13

Eronyxa Reitter, E. 1876: 57.

Type species:

Ostomodes dohrni Reitter, 1876 [by monotypy]

Barron, J. R. 1971: 38. Reitter, E. 1876: 57. Kolibáč, J. 2005: 55 (redescription). Kolibáč, J. 2006: 111 (phylogeny). Kolibáč, J. 2010: 35 (key). Léveillé, A. 1910: 28

Ostomodes Reitter, 1877 (Type species: Ostomodes dohrni Reitter, 1876)

Barron, J. R. 1971: 38. Léveillé, A. 1910: 28. Schaeffer, C. F. A. 1915: 69. Schaeffer, C. F. A. 1918: 200. Casey, 1916: 284. Crowson, R. A. 1964a: 290. Crowson, R. A. 1966: 125

Grynocharis (pars.)

Barron, J. R. 1971: 38. Van Dyke, E. C. 1916: 73

Remarks.

The genus was formerly classified within Decamerini ( Crowson 1964a and others). John Doyen (in Tait et al. 1990) described a larva of Eronyxa expansus and, considering its distinct similarity to known lophocaterine larvae, shifted Eronyxa to Lophocaterini . Although this classification was confirmed by myself ( Kolibáč 2006, 2008), both character analyses showed Eronyxa in a basal position of the lophocaterine clade (= Lophocaterini + Ancyronini ) along a border near the Decamerini - Lophocaterini split. However, the adult characters indicate a sister relationship with Decamerini [( Eronyxa ( Diontolobus + Decamerus )) ( Lophocaterini )] rather than Lophocaterini [( Diontolobus + Decamerus ) ( Eronyxa + Lophocaterini )]. See also “Remarks” in the Decamerini section.

Description.

Body size: about 3.5 mm. Body shape flat. Gular sutures wide, convergent at apex. Frontoclypeal suture present. Frons: longitudinal groove or depression absent. Cranium ventrally: tufts of long setae at sides absent. Submentum: ctenidium absent. Antennal groove absent. Eyes: size large, lateral. Eyes number: two. Epicranial acumination moderate. Lacinial hooks: two. Galea: shape very small. Galea: ciliate setae absent. Mediostipes-Lacinia not fused. Palpifer: outer edge even. Mandibular apical teeth number: two, horizontally situated. Mola present. Penicillus (at base) present (fine, often membranous). Pubescence above mola or cutting edge absent. Ventral furrow absent. Basal notch moderate. Labrum-Cranium not fused. Epipharyngial sclerite absent. Lateral tormal process: projection projections extending laterally and downwards (Eronyxa). Ligula: ciliate setae absent. Ligula membranous, not retroflexed, deeply emarginate. Hypopharyngeal sclerite absent. Antenna 11-segmented. Antennal club symmetrical, sensorial fields absent. Front coxal cavities externally open, internally open. Pronotum transverse. Prepectus present. Middle coxal cavities open. Elytra: long hairs absent. Epipleuron thin. Elytral interlocking mechanism absent, carinae reduced. Elytral punctation irregular, scales absent. Wing: radial cell moved down, often small, wedge cell absent, cross vein MP3-4 present, cross vein AA1+2-3+4 absent. Front tibiae: spines along side large. Hooked spur absent, apical spurs not hooked or weakly hooked. Claws: denticle absent. Parasternites number along ventrites III-VII: two. Spiculum gastrale absent. Tegmen composed of two parts. Coxitae divided.

Larva: Frontal arms V-shaped. Epicranial stem absent. Endocarina present. Gular sutures conspicuous, convergent. Paragular sclerites absent. Hypostomal rods absent. Stemmata number: two. Mandibular apical teeth number: two, horizontally even, vertically situated. Lacinia mandibulae plumose. Mola absent. Maxillary palpi 3-segmented. Palpifer present. Pedunculate seta absent. Mala simple. Mala: bidentate protrusion absent. Cardo-Stipes partially fused. Ligula present. Labial palpi 2-segmented. Prementum in two parts. Torma H-shaped. Antennal joints 1 and 2 elongate. Sensory appendix very small. Thoracic sclerites pattern (dorsally) 1-0-0. Thoracic sclerites pattern (ventrally) 1+0+0. Trochanter triangular. Abdominal segment IX transversely divided. Tergite IX flat. Urogomphi present, hooked; median process present.

Biology.

Eronyxa expansus was collected under the bark of Libocedrus (= Calocedrus ) decurrens. The larva probably feeds on Xylococculus macrocarpae ( Barron 1971, Tait et al. 1990). Eronyxa pallidus has been found on flowers, for example Aruncus sylvester and Ceanothus cuneatus , and an imago was reared from a stem of the latter plant. The third species, Eronyxa angustus , was also found on Fraxinus blossoms and on Pinus ponderosa ( Barron 1971).

Distribution.

Western states of USA (California, Idaho, Nevada, Oregon) and Canada (British Columbia).

Species:

Eronyxa angustus Casey, 1916; USA: California, Idaho, Nevada, Oregon (JRB)

Barron, J. R. 1971: 42. Kolibáč, J. 2005: 55 (redescription)

Eronyxa expansus Van Dyke, 1916; USA: California (JRB)

Barron, J. R. 1971: 38. Kolibáč, J. 2006: 107 (larva). Leschen, R. A. B. 2000: 920 (biology). Tait, S. M. et al. 1990: 13 (larva)

Eronyxa pallida Motschulsky, 1863; Canada: British Columbia, USA: California, Oregon (JRB)

Léveillé, A. 1910: 28. Barron, J. R. 1971: 39 (syn. Grynocharis pilosula Crotch, 1873; synonymized by whom?). Barron, J. R. 1971: 39 (syn. Ostomodes dohrni Reitter, 1877; synonymized by Léveillé 1910?). Barron, J. R. 1971: 39 (syn. Ostomodes lagrioides Reitter, 1876; synonymized by whom?). Crowson, R. A. 1964a: 291 ( Ostomodes ). Kolibáč, J. 2005: 55 (redescription). Reitter, E. 1876: 58 ( Eronyxa lagrioides )

Figures

Figure 10. A Thymalus limbatus B Phloiophilus edwardsi C Eronyxa marginicollis D Decamerus haemorhoidalis E Diontolobus punctatipennis F Afrocyrona ciskeiensis G Afrocyrona dwesae H Grynoma sp., New Zealand I Grynoma diluta.

Map 11. A distribution of the tribe Decamerini including the newly described genus † Cretamerus. A position of Eronyxa is indicated.

Figure 13. A-B Calitys scabra (A head and pronotum B elytral apex with interlocking mechanism) C-D Acalanthis quadrisignata (C apex of protibia with hooked spur and lateral spines D sculpture of frons with punctures conjoined into wrinkles) E-H Gymnocheilis sp., Cameroon (E head F protibia G elytral apex H detail of scales).