Oesyperus Andrewes, 1923

Kataev, Boris M., 2006, A taxonomic review of the genus Oesyperus (Coleoptera: Carabidae: Harpalini), Zootaxa 1286, pp. 43-55 : 44-47

Oesyperus Andrewes, 1923 , stat. rest.

Oesyperus Andrewes, 1923: 444 (as a genus). Type species Oesyperus unctulus Andrewes, 1923 , designated by Andrewes (1939: 136).

Oesiperus: Csiki, 1932: 1210 (incorrect subsequent spelling).

Oesyparus: Andrewes, 1939: 136 (incorrect subsequent spelling).

Merklia Ito, 2004: 107 (as a genus), syn. n. Type species Merklia pubens Ito, 2004 (= Oesyperus unctulus Andrewes, 1923 ), by original designation.

Merklophonus Ito, 2005: 53 (as a genus), nomen pro Merklia Ito, 2004 (non Chen, 1997), syn. n.

Diagnosis. Within the Selenophori group, Oesyperus is clearly distinguished by the combination of the following character states: dorsum punctate and pubescent; head with clypeo­ocular prolongations; supraorbital furrows deep, more or less straight and prolonged to neck constriction behind eyes; mandibles elongate, evenly curved and acute at apices; mentum with median tooth; antennae pubescent from apical half of second antennomere (first antennomere also with several short setae apically); elytra with rows of discal setigerous pores at least on third intervals; and tarsi pubescent dorsally. Apical orifice of aedeagus in dorsal position and covered by sclerotized plica at apex.

Description. Size: Body small to moderate (about 6.0–11.0 mm).

Colour: Body dark, not iridescent and without metallic lustre; appendages pale.

Dorsal pubescence: Dorsum almost throughout (except for eyes, labrum and mandibles) covered with short erect black setae.

Head: Moderate or rather large, with small eyes and wide genae. Temples long, distinctly pubescent. Frontal suture narrow and shallow; clypeo­ocular prolongations reaching supraorbital furrows. Supraorbital furrows somewhat deep, more or less straight and prolonged to neck constriction behind eyes ( Figs 4–5 ). Apical margin of clypeus weakly arcuately emarginate, not bordered, and labral base invisible in emargination. Mentum ( Fig. 6 ) with a large acute tooth and with two medial setae, separated from submentum by complete suture. Epilobes narrow, slightly widened apically. Ligular sclerite narrow, with two ventro­apical setae, separated from glabrous narrow paraglossae by deep notches [ Andrewes (1923) statement that the paraglossae are setulose in Oesyperus is probably erroneous]. Basal palpomere not carinate. Penultimate palpomere approximately equal to or slightly longer than apical, with numerous setae on anterior margin. Mandibles rather long and acute, somewhat evenly curved to apex. Antennae moderately long, reaching elytral base, pubescent from apical half of second antennomere (first antennomere also with several short setae apically), but this pubescence sparser than in other antennomeres.

Pronotum: Sides each with one marginal seta; apical margin bordered only laterally, basal margin without distinct border (bead sometimes hardly distinct at basal angles), not ciliate on basal edge.

Elytra: Humeri more or less widely rounded at apices, without denticles. Additional ninth stria not separated from lateral furrow by convexity. Basal pore present. Each third interval with several (3–9) discal pores. Each fifth and seventh intervals without discal pores, or, discal pores, if present, hardly recognizable against backgrounds of general puncturation. Series umbilicate irregular, without a distinct gap medially.

Hind wings: Reduced to small scales.

Ventral surface: Metepisterna wider than long, weakly narrowed posteriad. Abdominal sternites densely punctate and covered with short setae. Anal sternite rounded at apex, with two pairs of setae at apical margin.

Legs: Protibia not sulcate, with one or two preapical spines on outer margin and one ventroapical spine; apical spur slender, lanceolate. Metacoxa punctate, without additional setae. Metafemur with two or three setae along posterior margin. Tarsi densely pubescent dorsally. Metatarsus with first tarsomere much longer than second. In male, protarsomeres 1–4 moderately dilated, each with biseriate vestiture ventrally, first mesotarsomere longer than second, not dilated and without vestiture ventrally; mesotarsomeres 2–4 comparatively weakly dilated, each with biseriate vestiture ventrally.

Male genitalia: Median lobe of aedeagus ( Figs 7–14 ) arcuate, with rather short terminal lamella, more or less strongly bent dorsad at apex; ventral surface of median lobe unbordered. Apical orifice in dorsal position, extending basally and covered by more strongly sclerotized plica at apex. Internal sac without any distinct sclerotized structures.

Composition and distribution. The genus includes three species, all from southern India.

Remarks. The examination of the type material of three species included in Oesyperus showed that this taxon is a member of the Selenophori genus­group of the subtribe Harpalina because it possesses the following character states which are distinctive of this group: paraglossae glabrous, penultimate labial palpomere with several setae at anterior margin, third elytral interval with row of discal pores, and male pro­ and mesotarsi dilated and carring biseriate vestiture ventrally. Other character states of Oesyperus (distinct clypeo­ocular prolongations, rather long first metatarsomere, and dorsal position of apical orifice of median lobe of aedeagus) also substantiate this relationship. However, Oesyperus is not a member of the genus Parophonus , as suggested by Noonan (1985a), since it clearly differs in having the rather elongate mandibles. Based on the latter character, Oesyperus should, in my opinion, be included in the Oxycentrus stock sensu Noonan (1985b) which comprised two phyletic lineages (groups), both restricted mainly to the Oriental Region: 1) Hyphaerion MacLeay sensu lato (including Calathomimus Bates , Coleolissus Bates , Tenuistilus Habu , and Allosiopelus Ito ) and 2) Oxycentrus Chaudoir sensu lato (including Oxycentropsis Schauberger , Paroxycentrus Ito , and Trichoxycentrus Ito ). These two groups differ chiefly in the body shape (more or less oval, somewhat robust in Hyphaerion , and elongate, often cylindrical in Oxycentrus ) and apparently represent two different adaptive morphological types associated with different modes of life (probably surface or litter dweller in Hyphaerion , and hole dweller or burrower in Oxycentrus ). Members of Oxycentrus are also characterized by the particularly long mandibles, usually more elongate than those in species of Hyphaerion . Both Oxycentrus sensu lato and Hyphaerion sensu lato need revision and the taxonomic status of some of the included taxa invites further investigation. Based on the somewhat robust body and moderately long mandibles, Oesyperus is more similar and probably more closely related to Hyphaerion than to Oxycentrus . However, it seems to represent a separate genus clearly distinguished from the both by the pubescent body and the modified supraorbital furrows which are deep, more or less straight and prolonged to the neck constriction behind eyes. The latter character state is known to me only for some species of Trichotichnus Morawitz. According to the original description ( Ito 2000), the monotypical genus Trichoxycentrus possesses pubescence on the dorsal surfaces of the head and tarsi, but, unlike Oesyperus , the pronotum and elytra are glabrous. In addition, Trichoxycentrus , which is certainly closely related to Oxycentrus , shows other remarkable morphological characters (ligular sclerite quadrisetose, legs densely setose dorsally, prosternum and ventral surface of head densely covered with long setae) differing not only from Oesyperus but also from other related genera. In my opinion, the presence of dorsal pubescence in Oesyperus and Trichoxycentrus is not an indication of affinity. It is well known that many groups of Harpalini have dorsal pubescence and in many cases it evolved independently.

Recently, Ito (2004) established a new selenophorine genus Merklia with a single newly described species M. pubens . Because the name Merklia had already been used in 1997 for a Lagriidae genus, Ito (2005) replaced it by the new name Merklophonus. Ito (2004) described this genus without reference to Oesyperus and mentioned only that it “might be related to the genera Parophonus Ganglbauer , Ophoniscus Bates , Trichotichnus Morawitz, Coleolisssus Bates , Hyphaereon MacLeay , Oxycentrus Chaudoir , and Trichoxycentrus N. Ito ”. Unfortunately, both Merklia Ito and Merklophonus are objective synonyms of Oesyperus since the type species of the first two taxa is conspecific with the type species of Oesyperus (see below).

It is interesting to note that, although all three species of Oesyperus differ sharply from each other by their appearance, they have very similar male genitalia.

Figures

FIGURES 4 – 5. Oesyperus, head, lateral aspect. 4, Oe. planus; 5, Oe. pygmaeus. Scale = 1.0 mm.

FIGURES 6 – 8. Oesyperus unctulus. 6, labium; 7, median lobe, lateral aspect; 8 – same, dorsal aspect. Scales = 0.5 mm (A: 6, B: 7 – 8).