Thyreocephalus Guerin-Meneville 1844
Creators: name: Janák, Jiří
name: Bordoni, Arnaldo
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Thyreocephalus

description: Thyreocephalus Guérin-Méneville, 1844
Thyreocephalus Guérin-Méneville, 1844: 10; Sharp, 1885: 498; Cameron, 1921: 354; Steel, 1938: 55; Blackwelder, 1943: 490; 1952: 390; Coiffait, 1968: 128 and 152; Smetana, 1977: 348; 1982: 66; Moore & Legner, 1979: 76, Bordoni, 2002: 210; 2005a: 478; 2005b: 354; 2010: 318; Navarette-Heredia et al. 2002: 319; Newton et al. 2001: 328 et 392, 2005: 48; Janák, 2010: 130; Asenjo et al. 2013: 359.
Linidius Sharp, 1876: 196; Steel, 1938: 56.
Saurohypnus Sharp, 1885: 501; Casey, 1906: 373; Arnett, 1960: 247; Moore, 1963: 94; Moore & Legner, 1974: 557.
Indoscitalinus Heller, 1900: 5; Cameron, 1932: 33; Steel, 1938: 55; Shibata, 1973: 126.
Type species: Thyreocephalus jekelii Guérin-Méneville, 1844, established by Lucas, 1920 by subsequent designation.
The following redescription is based on redescriptions by Smetana (1982) and Janák (2010) and is completed and extended for hitherto revised species from various regions.
Redescription. Form elongate, stout, of large to very large size (9–25 mm).
Head variably punctate (Figs. 24, 127, 129), punctures not forming semi-impressed rows of coalescent grooves, frontal grooves short or moderately long, ocular grooves less deep, inconspicuous or absent. Anterior margin of frons between antennal insertions extended into short and very wide, apically truncate process, limited at each side by rounded emargination, and slightly impressed dorsally. Eyes small, temples longer than length of eyes seen from above, evenly rounded, hind angles rounded or acute. Antennae geniculate, moderately short, antennal insertions separated from each other by distance about equal to distance separating each insertion from anteromedian margin of eye, first segment long, thickened towards apex, equal in length to at least the four following segments combined, second segment shorter than third, distal segments more or less transverse. Labrum completely chitinised, short, transverse, more or less lobate (e.g., Figs. 31, 76, 159) or rounded (Fig. 131) apically, with long and strong apical setae. Mandible stout, lateral furrow reduced to vague impression at base. Maxillary palpi moderately long, segment 3 shorter than segment 2, segment 4 longer and somewhat narrower than segment 3, subacute apically. Labial palpi moderately long, last segment distinctly longer than segment 2. Mentum short, transverse, pentagonal. Ligula divided. Gula very short, gular sutures contiguous or narrowly separated posteriorly.
Pronotum without dorsal rows of punctures, with one big puncture (without seta) close to anterior angles (e.g., Figs. 23, 25); antesternal plate with a suture (Fig. 26); both superior and inferior line of pronotal hypomera strongly developed, superior line turning downwards well before middle, joining or almost joining inferior line next to front margin of procoxae and continuing onto front margin of pronotum (Fig. 26). Prosternum (Fig. 26) elevated medioposteriorly, without or with posteromedian carina, intercoxal process protruding, triangular (Fig. 26); epimera present. Mesosternum very short, transverse, widely separating middle coxae. Metasternum very long.
Elytra overlapping at suture (Figs. 22, 23). Legs moderately long; protarsi simple (not dilated) in either sex, first four segments gradually becoming shorter, last segment about as long as three preceding segments combined; protibiae with numerous strong spines on outer margin; mesotibiae strongly spinose, with apical ctenidium which extends onto inner margin backwards to about middle and with another similar ctenidium above it; first segment of mesotarsus and metatarsus about equally long as second, last segment about as long as preceding segments combined; metatibiae spinose on outer margin, with apical ctenidium which extends onto inner margin backwards to about middle, and with another similar ctenidium above it extending along outer margin to about middle (Figs. 27, 28).
Abdomen (Figs. 22, 23) ‘Staphylininae-shaped’ with fourth or fifth segment broadest. Tergite 7 with complete membranous palisade fringe at its posterior margin (Figs. 22, 23).
Male. Tergite and sternite 8 of male simple, not modified. Tergite 10 of male genital segment rather narrowly exposed between sclerites of tergite 9, strongly narrowed proximally (e. g. Figs. 32, 42), sclerites of tergite 9 contiguous mediobasaly. Sternite 9 of male genital segment asymmetrical, located centrally (e. g. Figs. 33, 43). Aedeagus with basal bulbus subovoid, median lobe of different length, symmetrical (e. g. Figs. 34, 79) or assymetrical (Figs. 69, 91) parameres and inner sac with shape of more or less long and wide ribbon with scales of different size.
Female. Genital segment with sternite proportionally short and two big supplementary sclerites that cover its proximal part (Fig. 217).
Differential diagnosis. This genus differs from several other genera of Xantholinini in the absence of dorsal rows of punctures on the pronotum (together with Achmonia Bordoni, 2004, Afrus gen. nov., Agerodes Motschulsky, 1858, Dibothroglyptus Scheerpeltz, 1957, Domea Bordoni, 2002, Eachamia Bordoni, 2005, Eulissus Mannerheim, 1830, Gauropterus Thomson, 1860, Liotesba Scheerpeltz, 1965, Oculolabrus Steel, 1946, Ulisseus Bordoni, 2002), in the punctures on the head not forming semi-impressed rows of coalescent grooves (in contrast to Gauropterus), in the absence of longitudinal furrows on the dorsal side of the temples (in contrast to Ulisseus), in the anterior angles of pronotum not emarginated (in contrast to Dibothroglyptus), in the superior line turning downwards well before middle and joining or almost joining the inferior line next to the front margin of procoxae and continuing onto the front margin of pronotum (in contrast to Achmonia, Agerodes, Domea, Eachamia, Eulissus, Liotesba and Oculolabrus) and in presence of a subapical ctenidium on the metatibia (in contrast to Afrus gen. nov.).
Geographical distribution. This genus is characteristic of warm regions of the earth and is well represented in Africa, Madagascar, Central and South America, in the Oriental Region from India and Nepal to Sulawesi, the Sunda islands, and the Moluccas (Bordoni 2002). Thyreocephalus is particularly represented in the Australian Region (Bordoni 2005a, 2010). The few species of New Zealand are introduced (Bordoni, 2005b). Two species are known from America North of Mexico (Smetana 1982).
Bionomics. The species belonging to this genus were collected in rotting matter, in debris, under stones, sometimes in dung, in carrion of small animals, in rotting fruits on the ground; some of them are probably subcorticicolous.
The pre-imaginal stages of T. albertisi were described by Marucci & Clancy (1952); Paulian (1941) described a larva attributed to T. anachoreta sensu auct. (= T. amphidaseus Bordoni, 2002). Dettner (1987) studied the defensive glands of this genus.
In Africa the genus can be divided into 9 distinct species groups, characterised by different composition of setiferous punctures on head, general appearance including colour of the body and the shape of the labrum. These species groups do not always reflect natural relationship, but can help with the identification of species.
description: Published as part of Janák, Jiří & Bordoni, Arnaldo, 2015, Revision of the genus Thyreocephalus and description of Afrus gen. nov. of Africa south of the Sahara (Coleoptera: Staphylinidae: Staphylininae), pp. 1-94 in Zootaxa 4038 (1) on pages 14-18, DOI: 10.11646/zootaxa.4038.1.1, http://zenodo.org/record/289876