Thymalus Latreille, 1802

Kolibac, Jiri, 2013, Trogossitidae: A review of the beetle family, with a catalogue and keys, ZooKeys 366, pp. 1-194 : 99-101

Genus Thymalus Latreille, 1802 Figs 10 , 16 , 18 ; Map 10

Thymalus Latreille, 1802: 133.

Type species.

Peltis brunnea Thunberg, 1794 (= Cassida limbata Fabricius, 1787) [by original designation and monotypy]

Léveillé, A. 1910: 32. Barron, J. R. 1971: 35. Crowson, R. A. 1964a: 296. Kolibáč, J. 2005: 85 (redescription). Kolibáč, J. 2006: 111 (phylogeny). Kolibáč, J. 2007a: 366. Nikitsky, N. B. et al. 1998: 29 (key). Lafer, G. Sh. 1992: 83. Reitter, E. 1876: 64

Thymalops Iablokoff-Khnzorian, 1962 [Type species: Cassida limbata Fabricius, 1787]

Barron, J. R. 1971: 35. Iablokoff-Khnzorian, S. M. 1962: 421

Remarks.

Comparing the larvae as well as adults of Thymalus and Protopeltis , I found some interesting similarities, which led me to consideration of their phylogenetic relationship. Later character analysis ( Kolibáč 2006) showed a relationship of Thymalus and Protopeltis with the former Rentoniini Crowson, 1966. This in turn led to the establishment of the tribe Thymalini for the group. However, Crowson (1966, 1970) also associated the former monotypic tribe Protopeltini Crowson, 1966 with the rentoniins. Recently, such a classification was called into question by Lawrence et al. (2011) and Leschen et al. (2012), who found Trogossitidae polyphyletic in their character analyses; however, both analyses were based on the same character states. Their model genera Thymalus and Rentonellum are classified outside Cleroidea in Lawrence et al. (2011) trees whereas Leschen et al. (2012), using a restricted character set, removed them only from Trogossitidae and/or suggested subfamily rank for rentoniins again, without necessarily believing in a mutual relationship between the two genera. Some more detail appears in “Remarks” with the tribe Thymalini .

Léveillé (1877) described the Caucasian species Thymalus aubei as Thymalus fulgidus var. aubei Léveillé, 1877. However, Thymalus fulgidus Erichson, 1844 was originally described from North America and Barron (1971) synonymized this species with Thymalus marginicollis Chevrolat, 1842. That is perhaps why the latter author also synonymized the taxon aubei as a synonym of marginicollis, probably without examination of the holotype or even Caucasian specimens. Russian entomologists, for example Nikitsky et al. (1998), consider Thymalus aubei a valid species, with the synonym Thymalus subtilis Reitter, 1889.

Description.

Body size: 4.3-7.5 mm. Body shape convex (not conglobate). Gular sutures wide, subparallel. Frontoclypeal suture absent. 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 elongate. Galea: ciliate setae absent. Mediostipes-Lacinia not fused. Palpifer: outer edge even. Mandibular apical teeth number: two, horizontally situated. Mola present. Penicillus (at base) absent. Pubescence above mola or cutting edge absent. Ventral furrow absent. Basal notch moderate. Labrum-Cranium not fused. Epipharyngial sclerite absent. Lat eral tormal process: projection projection not developed (all remaining). Ligula: ciliate setae absent. Ligula rigid, not retroflexed, weakly emarginate. Hypopharyngeal sclerite H-shaped. Antenna 11-segmented. Antennal club symmetrical, sensorial fields absent. Front coxal cavities externally open, internally closed. Pronotum transverse. Prepectus absent. Middle coxal cavities open. Elytra: long hairs absent. Epipleuron wide. Elytral interlocking mechanism absent, carinae reduced. Elytral punctation regular, scales absent. Wing: radial cell oblong (or reduced), wedge cell present, cross vein MP3-4 present, cross vein AA1+2-3+4 absent. Front tibiae: spines along side reduced. Hooked spur absent, apical spurs not hooked or weakly hooked. Claws: denticle absent. Parasternites number along ventrites III-VII: one. Spiculum gastrale absent. Tegmen composed of three parts.

Larva: Frontal arms V-shaped. Epicranial stem reduced. Endocarina absent. Gular sutures inconspicuous. Gula: anterior apodemes present. Paragular sclerites absent. Hypostomal rods present. Stemmata number: five. Mandibular apical teeth number: two, horizontally situated. Lacinia mandibulae with several small spines. Mola absent. Maxillary palpi 3-segmented. Palpifer present. Pedunculate seta absent. Mala simple. Mala: bidentate protrusion present. Cardo-Stipes partially fused. Cardo: size much smaller than stipes. Ligula present. Labial palpi 2-segmented. Prementum in single part, anterior margin even. Torma: two separate lateral sclerites. Antennal joints 1, 2 transverse. Sensory appendix larger than half of joint 3. Thoracic sclerites pattern (dorsally) 2-0-0. Thoracic sclerites pattern (ventrally) 0+0+0. Trochanter triangular. Abdominal segment IX not divided. Tergite IX flat. Urogomphi present, hooked; median process absent.

Biology.

The beetles are not associated with any particular tree species and are found on both deciduous and coniferous trees. Thymalus limbatus is known from the trunks of birch, beech, linden, and spruce, mostly under bark. It is assumed that the larvae feed on fungi in rotten or decaying wood ( Kolibáč et al. 2005). Thymalus marginicollis has been collected from the fungi Polyporus betulinus , Polyporus versicolor , Daedalea confragosa , on the trunks of birch and also on " wild flowers in plant press " ( Barron 1971).

Distribution.

Holoarctic: Northern states of USA, Canada, Europe, North Africa, Siberia to China and Japan. Some specimens, probably a new species, have recently been collected in Chinese Sichuan and Yunnan and also in northern Thailand.

Species:

Thymalus aubei Léveillé, 1877; “Batum”, Caucasus (varA)

Léveillé, A. 1910: 32. Klausnitzer, B. 1996: 156. Barron, J. R. 1971: 36 (syn. Thymalus aubei Léveillé, 1877 with Thymalus marginicollis Chevrolat, 1842). Barron, J. R. 1971: 36 (syn. Thymalus fulgidus var. aubei Léveillé, 1877 with Thymalus marginicollis Chevrolat, 1842). Kolibáč, J. 2007a: 366 (syn. Thymalus subtilis Reitter, 1889). Lafer, G. Sh. 1992: 86 ( Thymalus subtilis Reitter, 1889). Léveillé, A. 1910: 33 ( Thymalus subtilis Reitter, 1889). Nikitsky, N. B. et al. 1998: 28 (syn. Thymalus subtilis Reitter, 1889; lectotype designated). Nikitsky, N. B. & Semenov, V. B. 2001: 49

Thymalus chinensis Fairmaire, 1900; China: Fujian (JK)

Léveillé, A. 1910: 32. Kolibáč, J. 2007a: 366

Thymalus laticeps Lewis, 1894; Japan (varA)

Léveillé, A. 1910: 32. Esaki, T. et al. 1951: 1063. Kolibáč, J. 2007a: 366. Lafer, G. Sh. 1992: 86. Nakane, T. et al. 1963: 181

Thymalus limbatus Fabricius, 1787; Europe, North Africa: Tunisia (JK)

Léveillé, A. 1910: 32. Alexander, K. N. A. 1996: 90 (biology). Bahillo de la Puebla, P. & López-Colón, J. I. 1999: 13. Bahillo de la Puebla, P. & López-Colón, J. I. 2004: 129. Bercedo, P. et al. 2006: 180 (distribution). Borowiec, L. 1983: 15. Burakowski, B. et al. 1986: 123. Cunev, J. 1999: 76. Franz, H. 1981: 51-52 (distribution). Klausnitzer, B. 1976: 8. Klausnitzer, B. 1978: 176. Klausnitzer, B. 1996: 155. Kolibáč, J. 1993a: 20. Kolibáč, J. 1993b: 90. Kolibáč, J. 2002: 55 (larva). Kolibáč, J. 2005: 85 (redescription). Kolibáč, J. 2006: 110 (larva). Kolibáč, J. 2007a: 366 (distribution). Kolibáč, J. 2007a: 366 (syn. brunneus Thunberg, 1794). Kolibáč, J. 2007a: 366 (syn. rubiginosus Gmelin, 1790). Krasutskii, B. V. 1996: 274. Mitter, H. 1998: 561. Pileckis, S. & Monsevičius, V. 1995: 273. Ratti, E. 1997: 178. Reitter, E. 1876: 64. Theunert, R. 2006: 113-114 (distribution). Vogt, H. 1967: 18

Thymalus marginicollis Chevrolat, 1842; Canada, USA (JRB)

Barron, J. R. 1971: 36 (syn. Thymalus aubei Léveillé, 1877). Barron, J. R. 1971: 36 (syn. Thymalus fulgidus Erichson, 1844). Barron, J. R. 1971: 36 (syn. Thymalus fulgidus var. aubei Léveillé, 1877). Böving, A. G. & Craighead, F. C. 1931: 273 (larva). Dajoz, R. 1997: 44 (biology). Reitter, E. 1876: 64 ( Thymalus fulgidus Erichson, 1844: "Amer. bor.")

Thymalus oblongus Reitter, 1889; Russia: North and Central Europea teritorries, Sweden, East Siberia (JK)

Léveillé, A. 1910: 33. Lafer, G. Sh. 1992: 86. Kolibáč, J. 2007a: 366. Krasutskii, B. V. 2006: 763 (biology). Nikitsky, N. B. et al. 1998: 28 (lectotype designated)

Thymalus parviceps Lewis, 1894; Japan (varA)

Léveillé, A. 1910: 33. Esaki, T. et al. 1951: 1063. Kolibáč, J. 2007a: 366. Lafer, G. Sh. 1992: 86. Nakane, T. et al. 1963: 181

Thymalus punctidorsum Latreille, 1894; Japan (varA)

Léveillé, A. 1910: 33. Kolibáč, J. 2007a: 366. Lafer, G. Sh. 1992: 86. Nakane, T. et al. 1963: 181

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 10. A distribution of the tribe Thymalini including Rentonium - group.

Figure 16. A-F Colydiopeltis compactum (A ventral surface B procoxal area C head ventrally D detail of mouthparts E protarsus F apex of metatibia with row of spines) G-H Thymalus limbatus (G antenna H apex of protibia with straight spur).

Figure 18. A Thymalus limbatus, elytral apex with interlocking mechanism B-E Decamerus haemorhoidalis (B prothorax with partially closed procoxal cavities C metatarsal claws with denticle D protarsus with projecting empodium E irregular punctation of elytra) F Grynocharis oblonga, elytral sculpture G-H Lophocateres pusillus (G head in frontal view with deeply emarginate frontoclypeal suture H detail).