Oxytelus Gravenhorst, 1802

Lü, Liang & Zhou, Hong-Zhang, 2012, 3576, Zootaxa 3576, pp. 1-63 : 5-8

Genus Oxytelus Gravenhorst, 1802

Gravenhorst, 1802: 101 (11 spp.); Latreille, 1810: 182, 427 (designation of type species); Erichson, 1840: 785 (24 spp.); Gemminger and Harold, 1868: 648 (78 spp.); Bernhauer and Schubert, 1911: 109 (256 spp.); Winkler, 1925: 342 (Palaearctic region); Cameron, 1930: 211 ( British India; Shanghai, Taiwan); Scheerpeltz, 1933: 1093 (198 spp.; supplement to Bernhauer and Schubert (1911)); Blackwelder, 1943: 91; Fagel, 1956: 271 (elevation of Anotylus as valid genus); Herman, 1970: 408 (237 spp.); Shibata, 1973: 30 (Taiwan); Hammond, 1975: 147, 148 ( Ceylon; Hong Kong, Shanghai); Yuh, Paik, Kwon, and Lee, 1985: 227 ( Korea); Shibata, 1986: 118 (Taiwan); Schülke and Uhlig, 1988: 5; Newton, Thayer, Ashe, and Chandler, 2000: 380; Herman, 2001: 1415 (198 spp.); Biswas, 2003: 251 (Sikkim); Ades and Kendrick, 2004: 53 ( Hong Kong); Smetana, 2004: 516 (Palaearctic); Mukhopadhyay and Sar, 2007: 420 ( India); Lee and Ahn, 2007: 22 ( Korea); Szujecki, 2008: 167 ( Poland); Stan, 2008: 375 ( Romania); Lott, 2009: 28 ( Ireland & Britain); Samin, Zhou, and Imani, 2011: 279 ( Iran).

Type Species: Staphylinus piceus Linné, 1767 , designated by Latreille (1810: 427).

Synonymy.

Anisopsidius Fagel, 1960: 8 (Type Species: Anisopsis quadricollis Bernhauer , fixed by original designation). Makranczy, 2006: 75 (synonym of Oxytelus ).

Anisopsis Fauvel, 1904: 108 (Type Species: Anisopsis flexuosa Fauvel , fixed by subsequent designation by Lucas, 1920: 98). Makranczy, 2006: 75 (synonym of Oxytelus ).

Anisopsodes Fagel, 1960: 11 (Type Species: Anisopsodes ornatus Fagel , fixed by original designation); Herman, 1970: 404 (synonym of Paroxytelopsis ); Herman, 2001: 1464 (synonym of Paroxytelopsis ).

Basilewskyorus Fagel, 1957: 41 (Type Species: Oxytelus rugegensis Cameron , fixed by original designation). Herman, 1970: 408 (synonym of Oxytelus ); Herman, 2001: 1419 (synonym of Oxytelus ); Smetana, 2004: 516 (synonym of Oxytelus ).

Caccoporus Thomson, 1859: 43 (Type Species: Staphylinus piceus Linné , fixed by original designation). Gemminger and Harold, 1868: 648 (synonym of Oxytelus ); Bernhauer and Schubert, 1911: 109 (subgenus of Oxytelus ); Cameron, 1930: 212, 231 (subgenus of Oxytelus ; British India); Blackwelder, 1943: 91 (synonym of Oxytelus ); Herman, 1970: 408 (synonym of Oxytelus ); Herman, 2001: 1418 (synonym of Oxytelus ); Smetana, 2004: 516 (synonym of Oxytelus ); Mukhopadhyay and Sar, 2007: 420 (subgenus of Oxytelus ; India).

Epomotylus Thomson, 1859: 43 (Type Species: Oxytelus sculptus Gravenhorst , fixed by original designation). Gemminger and Harold, 1868: 648 (synonym of Oxytelus ); Bernhauer and Schubert, 1911: 109 (subgenus of Oxytelus ); Fagel, 1956: 270 (valid genus; Type species: Oxytelus sculptus Gravenhorst ); Herman, 1970: 408 (synonym of Oxytelus ); Herman, 2001: 1418 (synonym of Oxytelus ); Smetana, 2004: 516 (subgenus of Oxytelus ).

Hoplitodes Fauvel, 1904: 109 (Type Species: Hoplitodes echidne Fauvel , fixed by original designation). Makranczy, 2006: 75 (synonym of Oxytelus ).

Paranisopsis Cameron, 1938 a: 3 (Type Species: Paranisopsis dorylina Cameron , fixed by monotypy); Herman, 1970: 404 (synonym of Paroxytelopsis ); Herman, 2001: 1464 (synonym of Paroxytelopsis ).

Paroxytelopsis Cameron, 1933: 36 (Type Species: Paroxytelopsis dorylina Cameron , fixed by monotypy). Makranczy, 2006: 75 (synonym of Oxytelus ).

Tanycraerus Thomson, 1859: 43 (Type Species: Oxytelus luteipennis Erichson , fixed by original designation). Gemminger and Harold, 1868: 648 (synonym of Oxytelus ); Bernhauer and Schubert, 1911: 109 (subgenus of Oxytelus ); Cameron, 1930: 217 (subgenus of Oxytelus ; British India); Herman, 1970: 408 (synonym of Oxytelus ); Herman, 2001: 1418 (synonym of Oxytelus ); Smetana, 2004: 517 (subgenus of Oxytelus ).

Diagnosis. Labrum bi-lobed, with anterior margin broadly emarginate. Hypostomal sutures confluent in posterior portion. Gular sutures separated from the fused posterior tentorial pits, parallel in anterior half, and then sharply divergent posteriorly. Pronotum with lateral marginal bead present. Elytral epipleural ridge present. Scutellar impression diamond-shaped. Metatibia with longitudinal ctenidium of fine spinules. Tarsal formula 3-3-3; tarsomere 2 shorter than the first. Abdominal segments II to VII each with two pairs of laterosternites. Basolateral ridges present on abdominal tergites II to VII. Apico-medial hook present on ventral surface of aedeagal median lobe (except for O. armiger Fauvel ), and paramere with only single seta at near apex.

Characters important to classification. All the characters mentioned in this section are used in the key and the descriptions afterward. Most of them are important to classification and species identification, especially in dealing with those species similar in appearance. The characters on head and sternites VII and VIII were widely used in many previous articles, but we here as well as in the specific descriptions focus more on the genital characters that were not detailedly described before.

Eyes. As pointed out by Cameron (1930), eyes are two types in this group: one with fine facets ( Fig. 1A) and the other with coarse facets ( Fig. 1B). An interesting phenomenon is the species that are usually able to be captured by light traps have large-sized and coarse-faceted eyes, whereas those rarely captured by light traps have usually small-sized and fine-faceted eyes.

Sutures and ridges on head. Occipital suture is present in all the species from China, but interrupted in males of some species, so the vertex and the neck are integrated into a “vertex-neck zone” ( Fig.1E). There is a pair of paralateral sutures ( Fig. 1E) running subparallel with mid-longitudinal suture (if exists), starting from the dorsal tentorial pits (usually invisible from the exterior) and anteriorly directed. The paralateral sutures vary in lengths among species: shorter and reduced in O. incisus Motschulsky , O. subincisus Cameron , O. lucidulus Cameron , and piceus -allied species, while relatively longer and distinct in O. ailaoshanicus sp. nov., O. bajiei sp. nov., O. lividus Motschulsky , O. megaceros Fauvel (male), O. lucens Bernhauer , O. robustus Schubert , O. puncticeps Kraatz , O. punctipennis Fauvel , and O. tibetanus Bernhauer. Along but a little behind the occipital suture there is a ridge-like structure, defined as nuchal ridge ( Figs. 1C, D) by Smetana and Davies (2000), which is continuous medially in some species but interrupted in others. Dorsal basal ridge ( Fig. 1D), anterior to the postoccipital suture, is present in most species except for O. incisus and O. subincisus .

Two types of antenna. Type I ( Fig. 1F): antennomere 1 is the longest, slightly geniculate and equipped with a long seta at near middle; the other antennomeres are ringed with setae, and antennomere 3 is constricted near base, antennomere 4 is subglobose, and each of antennomeres 5–11 bears a basal dish (a “ridge” in the terminology of Hammond (1975)) and is rough and haired on the remaining surface, the ultimate antennomere elongated and subulate. Type II antenna ( Fig. 1G): antennomere 3 is dark and with the narrowest at the base; antennomeres 4–11 are covered with hairs and bear the basal dishes.

Ridges on elytra. A lateral longitudinal ridge ( Fig. 1J) can be observed, in some species, on the demarcation between disc and epipleuron in addition to the epipleural ridge ( Fig. 1K). In O. incisus and O. migrator Fauvel , the lateral longitudinal ridge is obsolete, where only a fine groove remains.

Ridges on abdominal sternites II–VIII. There are two ridges on sternites II–VIII (see Figs. 1L, M as examples): the basal ridge and the subbasal ridge. The area anterior to the basal ridge is usually membranized, but not so on sternite VIII of the male O. lucidulus , O. pallidipennis Cameron , and O. subferrugineus Cameron ( Figs. 10G; 19F), nor on sternite VII–VIII of the male O. lividus ( Figs. 1L; 8E, F). The subbasal ridge on sternite VIII is interrupted in males of O. lividus , O. lucidulus , O. pallidipennis , O. puncticeps , and O. subferrugineus ( Figs. 1L; 8F; 10G; 15F; 19F). In O. lividus , O. lucidulus , O. pallidipennis , O. subincisus , and the piceus -allied species, a short midlongitudinal internal ridge ( Fig. 1M) can be observed with penetrating light on the posterior part of sternite VIII.

Aedeagus. The median lobe is ovoid and somewhat elongate in some species. Out of the apical orifice the internal sac is everted with its membranous apex ( Figs. 1N, O). Different species have different in situ configurations of the internal sac with different sclerite-like or membranous structures, these pattern variations can be used in species identification. On the ventral surface of the median lobe, the apico-medial hook ( Figs. 1N, O) changes dramatically in its appearance and is of great significance in species identification ( Naomi 1990; Makranczy 2006). A pair of parameres ( Fig. 1P) has a very complicated construction and is well developed in the genus Oxytelus . The paramere is arm-like and bent at the middle to form a corner that we use as a landmark to demarcate the apical and the basal arm of each paramere.

Spermatheca. The spermatheca ( Figs. 1Q, R) is as well a useful taxonomic trait to recognize the species of Oxytelus . It is bent at the middle and thus forms a basal and an apical portion, and the basal portion is connected with a duct. In most of species included in this paper, the spermatheca looks like a comma, a hook, or the Greek letter “ʋ”, and is more or less inflated at base, but in O. subincisus , it is dumbbell-shaped and inflated at both base and apex.

Sexual dimorphism. In Oxytelus , most species display sexual dimorphism with their head size and structures ( Cameron 1930), as well as the morphology of sternites VII and VIII. In males, mandible is larger and stouter; clypeus more protruding or broader; temple longer, broader, more dilated; occipital suture more curved or interrupted medially. But the following species show little sexual difference in head morphology: O. migrator , O. nigriceps Kraatz , O. punctipennis , and O. subincisus . Moreover, males in the same species display allometric size variations with their head structures (including clypeus and temples): “major” and “minor” males, as conventionally called. The posterior margins of sternites VII and VIII are different between sexes and are important traits in species identification. They display more changes in males than in females.