Horaeomorphus imitator, ski, 2009

ski, P. Jałoszy, 2009, Four New Species Of Horaeomorphus Schaufuss From The Oriental Region (Coleoptera: Staphylinidae, Scydmaeninae), Raffles Bulletin of Zoology 57 (2), pp. 297-303 : 297-298

Horaeomorphus imitator , new species

( Figs. 1a , 2a, b , 4a )

Material examined. – Holotype. Male, two labels: “MINDANAO, 1-3. May \ MISAMIS OCC., 1700 m \ DON VICTORIANO \ Bolm lgt., 1996” [yellow, printed], “ HORAEOMORPHUS \ imitator m. \ HOLOTYPUS \ det. P. JAŁOSZY SKI, ‘08” [red, printed] ( SMNS).

Diagnosis. – The following set of characters is unique for this species: body nearly as long as 3 mm, brown, slender; pronotum strongly elongate, with three small ante-basal pits located in deep groove; metatrochanters in males strongly modified, each forming very long, slightly curved rod-like projection with rounded apex; aedeagus with very complicated, symmetrical internal armature composed of generally bell-shaped central complex, and each paramere with numerous apical setae, without subapical setae.

Male. – Body ( Fig. 1a ) large (length 2.93 mm), slender, very convex, moderately dark brown, vestiture slightly lighter than cuticle.

Head broadest at moderately large, strongly convex eyes, length 0.45 mm, width 0.60 mm; tempora slightly longer than eye in dorsal view, arcuate; vertex weakly convex, with pair of small but deep pits located near posterior margins of supraantennal tubercles; frons weakly convex; supraantennal tubercles very distinct, strongly raised, well delimited from frons but indistinctly delimited from vertex. Punctures on vertex and frons very fine, shallow and sparse, unevenly distributed, separated by spaces 2-4x as long as puncture diameters; setae moderately long, sparse, suberect to erect. Antennae moderately slender, shorter than half length of body, length 1.20 mm; relative lengths of antennomeres (shortest antennomere II as 1): 1.67; 1; 1.67; 1.5; 1.33; 1.17; 1.17; 1.33; 1.5; 1.67; 2.

Pronotum oval, elongate, broadest between anterior third and fourth, length 0.93 mm, width at base 0.45 mm, maximum width 0.73 mm; discal part moderately strongly narrowing posteriorly to sharply marked posterior constriction separating narrow basal collar; hind angles obtuse and blunt; posterior margin arcuate; posterior collar delimited from disc by transverse dorsal row of three small but deep pits located in narrow and deep groove. Punctures on disc very fine and shallow, unevenly distributed, those in middle are separated by spaces 2-5x as long as puncture diameters; vestiture sparse, moderately long, suberect.

Elytra strongly elongate, oval, more convex than pronotum, broadest near anterior third, length 1.55 mm, width 0.98 mm, EI 1.59. Humeral calli weakly marked, delimited from adsutural region by very short and shallow, broad basal impressions; basal foveae indiscernible; apices of elytra separately rounded. Punctures in anterior 2/3 of elytra much more distinct than those on pronotum, large but shallow and slightly diffused; in median part of each elytron separated by spaces slightly longer than puncture diameters, punctures are gradually smaller and shallower toward apices and lateral margins of elytra. Vestiture similar to that on pronotum but slightly longer and slightly more suberect. Metathoracic wings not studied.

Metatrochanters strongly modified, as in Fig. 4a .

Aedeagus ( Figs. 2a, b ) 0.65 mm in length; with moderately slender median lobe, apical part strongly narrowed, subtrapezoidal; internal sac symmetrical, with complicated, bell-shaped central complex; parameres slender, slightly exceeding apex of median lobe, each with four apical setae.

Female. – Unknown.

Etymology. – The specific epithet imitator refers to the overall resemblance of the new species to H. blattnyi , another Horaeomorphus known to occur in the Philippines.

Distribution. – Philippines: Misamis Occidental Prov: Mindanao Is.

Remarks. – Horaeomorphus imitator is very similar to H. blattnyi Jałoszy ski, 2004, known to occur on Luzon. These two species share a very similar body shape, highly modified metatrochanters, and the structures of the aedeagus. A major differences are the body length (> 3.3 mm in H. blattnyi vs. <3 mm in H. imitator ), the internal sac of the aedeagus (much more complicated in H. imitator ), and the parameres (with several setae distributed between middle and apex in H. blattnyi , and with only apical setae in H. imitator ).

Figures

Fig. 1. Dorsal habitus of holotype males: a, Horaeomorphus imitator, new species; b, Horaeomorphus minor, new species; c, Horaeomorphus fakfakensis, new species; d, Horaeomorphus samosirensis, new species (d). Scale bar = 0.5 mm.

Fig. 2. Aedeagus in ventral (a, c) and lateral (b, d) views: a, b, Horaeomorphus imitator, new species; c, d, Horaeomorphus minor, new species. Scale bar = 0.2 mm.

Fig. 4. Hind trochanter and femur (a), and hind trochanter, femur and tibia (b). Horaeomorphus imitator new species (a), Horaeomorphus samosirensis new species (b). Scale bar = 0.2 mm.