Thinodromus circulus (Bernhauer, 1922)

Makranczy, György, 2014, Review of the Thinodromus circulus species group (Coleoptera: Staphylinidae: Oxytelinae), Acta Entomologica Musei Nationalis Pragae 54 (2), pp. 539-554 : 542-544

Thinodromus circulus (Bernhauer, 1922)

( Figs 1 , 5–10 , 21–22 , 32 )

Trogophloeus circulus Bernhauer, 1922a: 3 (original description). Trogophloeus (Carpalimus) circulus: SCHEERPELTZ (1933) : 1081 (catalogue). Thinodromus circulus: HERMAN (1970) : 387 (catalogue), HERMAN (2001): 1765 (catalogue).

Type locality. Bolivia, Cochabamba, Yuracares, approx. 15°56ƍS, 65°30ƍW.

Type material examined. LECTOTYPE (here designated): J, ‘Yuracaris, Bolivien; A. Fauvel determ. [label cut in two] \ circulus; Bernh.; Typus. \ circulus Fauv. ; i.l. Mus. Hamburg \ Chicago NHMus; M. Bernhauer; Collection \ Lectotypus; Trogophloeus ; circulus Bernhauer ; des. Makranczy, 2013 \ Thinodromus ; circulus (Bernhauer) ; det. Makranczy, 2013 ’ ( FMNH). PARALECTOTYPES: 3 JJ 1 ♀ ‘Yuracaris; Bolivie \ circulus; Fvl. \ Coll. et det A. Fauvel ; R.I.Sc.N.B. 17.479 \ Paralectotypus; Trogophloeus ; circulus Bernhauer ; des. Makranczy, 2013 \ Thinodromus ; circulus (Bernhauer) ; det. Makranczy, 2001’ ( ISNB, 1 J in HNHM).

Redescription. Measurements (in mm, n = 5): HW = 0.40 (0.39–0.42); TW = 0.395 (0.39– 0.41); PW = 0.44 (0.43–0.45); SW = 0.54 (0.52–0.56); AW = 0.59 (0.56–0.63); HL = 0.26 (0.24–0.27); EL = 0.12 (0.12–0.13); TL = 0.07 (0.06–0.07); PL = 0.33 (0.32–0.35); SL = 0.59 (0.57–0.60); SC = 0.56 (0.54–0.57); FB = 1.21 (1.16–1.26); BL = 2.24 (2.17–2.31). Lustre and colour. Body medium dull, especially head and pronotum, due to surface sculpture, with only tiny glittery spots; rest of body more lustrous. Head, pronotum and abdomen very dark brown. Elytra just a little bit lighter, dark brown with some reddish tint. Antennae dark brown but basal 1/3 conspicuously lighter, light brown, even yellowish at base. Legs and mouthparts medium to dark brown but tarsi and tibiae (especially both ends) often lighter then femora. Shape and sculpture. Forebody as in Fig. 1 . Head quite transverse, with large eyes and well developed, bulging temples nearing half the size of eyes. Neck delineated only by different, alveolate microsculpture, but without transversal groove. Antennae rather short, antennomeres slightly transverse: antennomeres 4 and 5 1.00–1.06× and 1.03–1.08× broader than long, respectively, antennomeres 9 and 10 1.30–1.38 and 1.60–1.70× broader than long, respectively. Pronotum rather transverse, strongly obtuse-angled anterior corners super¿cially appear somewhat rounded but still marked. Posterior half of pronotal sides quite straight, even feebly concave; posterior corners obtuse-angled and rounded. Horseshoe-shaped impression slightly marked except posterior/median part where rather impressed; slight lateral depressions connected by it. Middle of disc bearing pair of shallow depressions. Slight (thin) marginal bead (mostly lateral) observable only in slightly lateral view. Elytra combined imperceptably broader than long, gently dilated toward apex, with a pair of small, oval, slightly elongate impressions behind scutellum and extending posteriorly in longitudinal impressions, connected to somewhat depressed centre of elytral disc. Posterior elytral margin (slightly oblique) with very thin bead and in outer 1/3 with small membranous lobe protruding. Apex of abdominal tergite VII with palisade fringe. Punctation and microsculpture. Head and pronotum densely but not too deeply punctured, yet appearance dominated by acinose microsculpture; puncture interspaces on average smaller than puncture diameters. Punctation denser near the edges than at centre of discs. Epistomal suture barely marked by transversal strigulate microsculpture. Elytral punctures only slightly larger in size but interspaces much larger and with more conspicuous microsculpture only apparent at the scutellar area, otherwise quite indistinct. Consequently, elytral surface more lustrous, even a little more than abdomen bearing strong coriaceous/imbricate microsculpture (with isodiametric or slightly transverse cells) giving a greasy lustre. Abdominal punctures tiny and scattered. Pubescence. Body setation ¿ne, short and medium dense and equal sized on head and pronotum, a little longer and less dense on elytra. Longer hairs only on abdomen, especially apices of segments; otherwise elytral and abdominal setation with approximately the same density. Primary and secondary sexual features. Male sternite VIII as in Fig. 6 , male tergite IX as in Fig. 7 , male sternite IX as in Fig. 8 ; tergite VIII ( Fig. 21 ) and tergite X ( Fig. 9 ) seemingly not different between sexes. Aedeagus as in Fig. 22 . Spermatheca as in Fig. 10 , female ringstructure as in Fig. 32 .

Differential diagnosis. This species is distinguishable from T. velutinus by its less conspicuously strong punctation of the head and pronotum. These two Neotropical species differ from the rest of the treated taxa by the less elongate antennae (mid-antennal segments more or less isodiametric or transverse, never elongate).

Distribution. This species is known only from its type locality in Bolivia.

Remarks. A short series of specimens are the only material available of this species and no further data survived. The series was ¿rst studied by Albert Fauvel, but had remained undescribed by him. Finally, a year after Fauvel’s death, Max Bernhauer published an article with Fauvel’s names, validating these taxon names. BERNHAUER (1922a) gave no further information on how this material came to him. The lectotype is chosen to ¿x the interpretation of this taxon.

Figures

Figs 1–4. Forebodies of Thinodromus species. 1 – T. circulus (Bernhauer, 1922); 2 – T. chagosanus (Bernhauer, 1922); 3 – T. palustris (Bernhauer, 1922); 4 – T. arcitenens (Fauvel, 1905).

Figs 5–14. 5–10 – Thinodromus circulus (Bernhauer, 1922) (5 – mesotarsus; 6 – male sternite VIII; 7 – male tergite IX; 8 – male sternite IX; 9 – male tergite X; 10 – spermatheca); 11–12 – T. velutinus (Sharp, 1887) (11 – tergite X; 12 – spermatheca); 13–14 – T. chagosanus (Bernhauer, 1922) (13 – mesotarsus; 14 – platelike armature in hypopharynx). Scale bar: 0.06 mm for 14; 0.07 mm for 5, 13; 0.1 mm for 10–12; 0.12 mm for 8–9; 0.14 mm for 6–7.

Figs 20–24. 20 – Thinodromus velutinus (Sharp, 1887), tergite VIII; 21–22 – T. circulus (Bernhauer, 1922): 21 – tergite VIII, 22 – aedeagus; 23–24 – T. chagosanus (Bernhauer, 1922): 23 – male sternite IX, 24 – aedeagus. Scale bar: 0.1 mm for 20–21; 0.15 mm for 22–24.

Figs 31–35. 31 – Thinodromus velutinus (Sharp, 1887), female ringstructure. 32 – T. circulus (Bernhauer, 1922), female ringstructure. 33–34 – T. palustris (Bernhauer, 1922): 33 – male sternite IX, 34 – aedeagus. 35 – T.arcitenens (Fauvel, 1905), aedeagus. Scale bar: 0.1 mm for 31; 0.12 mm for 32, 35; 0.15 mm for 33; 0.2 mm for 34.