Thoracophorus perplexus, Irmler, Ulrich, 2015

Irmler, Ulrich, 2015, Four new species of the genus Thoracophorus Motschulsky, 1857 for the Neotropical region (Coleoptera: Staphylinidae: Osoriinae), Zootaxa 4039 (3), pp. 431-444 : 440-441

Thoracophorus perplexus n. sp.

Figs. 5 A, B, C, 10D

Type material. HOLOTYPE. male, French Guyana: Coralie (52°21.38'W, 4°30.41'N), male, 15.11.2011, leg. T. Struyve ( UIC). PARATYPES: 1 male, 2 females from same location and at same date as holotype (1 TSC, 2 UIC).

Diagnosis. Among the species of the genus with the lateral margin of the pronotum not denticulate, T. perplexus n. sp. represents a species that seems to be intermediate between T. filum Sharp, 1887 and T. exilis ( Erichson, 1840) . The elytral carinae and swellings on the head are more distinctly developed than in the species of T. filum Sharp, 1887 group, but less developed than in T. exilis (Erichson, 1887) . Furthermore, it resembles T. filum Sharp, 1887 in the orange colouration of the pronotum. In contrast to T. filum Sharp, 1887 , the elytra of T. perplexus n. sp. are only orange in the anterior half, whereas they are totally orange in T. filum Sharp, 1887 . T. perplexus n. sp. is slightly longer than T. filum Sharp, 1887 . The elytra are quadrate and not longer than wide such as in T. filum Sharp, 1887 . In this respect it also resembles T. verhaaghi n. sp. But T. verhaaghi n. sp. is slightly larger and nearly totally orange. On average, it is also slightly smaller than T. exilis ( Erichson, 1840) , T. proximus Irmler, 1985 and T. struyvei n. sp. It is mainly differentiated from these species by the aedeagal characters. Such as in T. proximus Irmler, 1985 the paramera are distinctly longer than the central lobe, but a transparent lobe is not separated at the apex of the paramera and the inner edge of the apical lobe is slightly sinuate and not straight. Only a few sensillae occur at the base and the apex of the paramera, whereas sensillae are concentrated on the apical plate in T. struyvei n. sp. and at the base of the paramera in T. proximus Irmler, 1985 . In addition, the temples are more rounded than in the two other species and the posterior angles are only slightly obtuse with a short nearly parallel part directly behind the eyes.

Description: Length: 1.6 mm. Colouration: black; clypeus, pronotum on lateral and posterior parts and elytra at shoulders orange.

Head: 0.20 mm long; 0.27 mm wide; eyes large; slightly prominent; temples short; only one fourth as long as eyes; narrowed to neck in short convex curve; posterior angles of temples 120°; clypeus approximately semicircular; front edge margined; without punctation; pair of elongate swellings on vertex indistinct; with slight impression between them, but without impression between swellings and eyes; isodiametric microsculpture deep and coarse; surface matte.

Antennae as long as head and half of pronotum combined; slightly clavate; first and second antennomeres thick; first approximately rectangular; second oval; antennomeres three to six distinctly narrower than preceding two antennomeres; conical third antennomere slightly shorter than second; fourth to sixth antennomeres approximately quadrate; seventh antennomere slightly wider than preceding antennomeres; following antennomeres distinctly wider than preceding antennomeres; eighth antennomere considerably wider than long; tenth antennomere slightly wider than long and wider than first.

Pronotum: 0.25 mm long, 0.30 mm wide; widest in anterior half; anterior half parallel; anterior angles approximately rectangular; posterior half deeply sinuate to posterior angles; posterior edge one third smaller than anterior edge; sides of anterior half indistinctly crenulate; central impression moderately deep; in anterior half deeper than in posterior half; central impression with oval swelling; moderately deep lateral impression elongate; extending from posterior angles to anterior angles; posterior edge with white short scales; without punctation; isodiametric microsculpture deep and dense; surface matte.

Elytra: 0.35 mm long, 0.35 mm wide; sides parallel; shoulders and posterior angles obtusely rounded; three indistinct carinae on each side of suture; without punctation; few white short scales at posterior margin; isodiametric microsculpture deep and dense; surface matte.

Abdomen parallel; segments III to V with weak transverse impression at base; with extremely fine punctation; punctures with short white scales; isodiametric microsculpture dense and deep; slightly less deep than on elytra; surface matte.

Aedeagus with obtuse angle between basal and apical lobe; apical lobe long; in lateral aspect, inner edge of apical lobe sinuate; endophallus with thick basal bulb and long ductus widened apically; paramera long and slender; projecting apical lobe; few sensillae at apex and at middle.

Etymology. The specific name derives from the same Latin word meaning confused and refers to the high similarity between the species described here.

Figures

FIGURES 4 – 8. Thoracophorus struyvei (4); T. perplexus (5); T. proximus (6); T. exilis (7); T. aequalis (8); aedeagus in lateral aspect (A), antenna (B), shape of temples (C); scale bar: 0.1 mm.