Tychobythinus araneipes ( Normand, 1930 )

Besuchet, Claude, Cuccodoro, Giulio & Sabella, Giorgio, 2013, On the genera Acanthobythus Normand, 1930 and Ceratobythus Normand, 1932 (Coleoptera: Staphylinidae: Pselaphinae), Revue suisse de Zoologie 120 (2), pp. 271-280 : 272-276

Tychobythinus araneipes ( Normand, 1930) Figs 1-4

Bythoxenus (Acanthobythus) araneipes Normand, 1930: 163 , figs 1 (habitus) and 2 (head, lateral

view);

Acanthobythus araneipes . – Jeannel, 1956: 65, figs 59 (habitus) and 60 (maxillary palpus).

TYPE MATERIAL: Lectotype (present designation); Northeastern Algeria, Skikda province; male, Philippeville , route de Collo, X.1929 (H. Normand) ( MHNG) . Paralectotypes, 2 females, same data as lectotype ( MHNG) .

FIG. 1 Dorsal habitus of Acanthobythus araneipes , lectotype. Scale bar 1 mm.

FIGS 2-4

Acanthobythus araneipes , lectotype. (2) Head and maxillary palpi, dorsal view. (3) Base of antenna. (4) Aedeagus, dorsal view. Scale bar 0.1 mm.

REDESCRIPTION: Body (Fig. 1) 1.40-1.45 mm long, uniformly pale brownreddish; wingless and anophthalmous. Pubescence fairly uniform, slightly longer on anterior portion of elytra and denser on pronotum, consisting of setae distant from each other by approximately their length, slightly arcuate and semi-erect to recumbent, predominantly about as long as apical width of metafemora (0.06 mm).

Head (Fig. 2) with frontal lobe moderately depressed medially. Tempora bearing each a conspicuous, acute spine (length 0.06-0.07 mm) obliquely oriented dorsally and slightly curved posteriorly, sharp clypeal ridge extended posteriorly to tip of each temporal spine. Occipital region slightly convex, with short medial occipital carina. Antennae (Fig. 3) 0.80 mm long with scapus more than 5 times as long (0.27 mm) as wide (0.05 mm), antennomere II oval (length 0.07 mm; width 0.04 mm). Maxillary palpi (Fig. 2) with segment I almost indistinct; II (length 0.22 mm; width 0.02-0.04 mm) distinctly curved on apical half and gradually enlarged until apical third, with posterior surface covered with tubercles distant from each other by slightly more that their diameter; III (0.07 mm / 0.04 mm) fairly oval, bearing a few tubercles; IV (0.25 mm / 0.09 mm) securiform and finely pubescent, its lateral margin slightly concave.

Pronotum wider (0.33 mm) than long (0.30 mm), almost spherical, narrower anteriorly than posteriorly with maximal width at anterior third; antebasal sulcus wellmarked, joining lateral foveae. Disc covered in middle with shallow areolate punctation and laterally with tubercles separated from each other by 3-4 times their diameter.

Elytra wider (0.56 mm) than long (0.50 mm), more convex transversely than longitudinally; pair of deep basal elytral foveae, internal fovea joint to complete sutural stria and external fovea extended by rather wide and deep depression reaching elytral mid-length at most; subhumeral elytral fovea extended dorsally by short vertical carina and ventrally by entire lateral carina.

Metasternum with lateral mesocoxal and lateral metasternal foveae deep and tomentose.

Abdomen rather long (0.52 mm) with first tergite 0.15 mm long; each tergite with a pair of long discal setae.

Legs with trochanters simples; anterior edge of protrochanters with 3-4 small prominent tubercles; metatrochanters much longer than mesotrochanters. Profemora relatively robust (0.38 mm / 0.09 mm) bearing on anterior margin row of 14 tubercles, first 4-5 more prominent than others; mesofemora (0.42 mm / 0.07 mm) and metafemora (0.51 mm / 0.06 mm) more slender. Protibiae (0.39 mm / 0.02-0.04 mm) and mesotibiae (0.40 mm / 0.02-0.04 mm) straight; metatibiae (0.55 mm / 0.02-0.05 mm) somewhat curved subapically. Metatarsi very thin (length I: 0.03 mm; II: 0.19 mm and III: 0.11 mm) with single claw (length 0.02 mm).

Male: Gular region behind labium with deep and broad depression margined posteriorly by conspicuous transversely compressed acute medial process projecting ventrally, latter medially sulcate and bearing two tufts of modified setae grouped at tip; gular region behind that process vertical, laterally with two deep longitudinal sulci bearing each a long semi-erect seta apically arcuate anteriorly. Aedeagus (Fig. 4), 0.22 mm long, with parameres apically acuminate and straight, each bearing with four small denticles on outer margin; internal sac with 7 thin and slender sclerites.

Female: Gular region behind labium shallowly depressed; posterior portion convex, with a medial ridge, and laterally with two shallow longitudinal sulci bearing each couple of long semi-erect setae apically arcuate anteriorly.

COMMENTS: Tychobythinus araneipes is the only member of the genus to possess conspicuous temporal spines.

The species is known only by the types, which were collected in October by soil washing at base of oaks and around roots of Asphodelus sp. The statement of Jeannel (1956) that the species was known only from female sex was erroneous.

In box 67 of the collection the “Afrique du Nord” in MNHN we found a mounting card bearing remnants of glue and with attached label “ Acantobythus araneipes Philippeville X.1929 Normand ”; these may have belonged to the second male and 4 th type mentioned by Normand in the original description (probably examined by Jeannel).