Revised concept of the genus Euryporus Erichson (Coleoptera, Staphylinidae, Staphylininae) and phylogenetic significance of Staphylinini from New Guinea

Abstract The Staphylinini rove beetle genus Euryporus Erichson from the subtribe Quediina is restricted to include only three species from the Western Palearctic region: Euryporus picipes (Paykull, 1800), Euryporus aeneiventris (Lucas, 1846), and Euryporus princeps Wollaston, 1864. Euryporus argentatus Fauvel, 1881, Euryporus warisensis Last, 1987 and Euryporus multicavus Last, 1980, which do not even belong to the subtribe Quediina, are excluded fromthe genus. Of these, two were transferred to different genera: Tympanophorus argentatus (Fauvel, 1881), comb. nov., from Sumatra;and Hesperus warisensis (Last, 1987), comb. nov.,from New Guinea. “Euryporus” multicavus could not be placed to any of the described genera of Staphylinini and is left as incertae sedis pending a broader study of the relevant fauna of this tribe in New Guinea and adjacent regions. The taxonomic history of Euryporus is reviewed, and an updated diagnosis of this genus is provided.


Introduction
An abundance of large and polyphyletic, poorly defined genera is a drawback of the current classification of the hyper-diverse rove beetle tribe Staphylinini (e.g., "Quediuscomplex" discussed in Solodovnikov 2006). By including numerous unrelated species together, such "genera" inhibit species discovery and taxonomic revisions, and they introduce "noise" in any evolutionary study of rove beetles. However, a number of monobasic or species-poor genera of Staphylinini suffer from the flawed definition too.
One such small genus that nevertheless turned out to be a taxonomic "waste basket" is Euryporus Erichson, 1839 from the subtribe Quediina. Prior to this paper Euryporus comprised three well-known species from the Western Palearctic region (E. picipes (Paykull, 1800) ( Fig. 1), E. aeneiventris (Lucas, 1846), and E. princeps Wollaston, 1864), and three poorly known "exotic" species: Euryporus argentatus Fauvel, 1881 from Sumatra (Fig. 2), as well as E. warisensis Last, 1987 (Figs 3-7) and E. multicavus Last, 1980 (Figs 8-11) from New Guinea. Poor descriptions of these "exotic" species coupled with the unusual disjunct distribution of the genus cast strong doubts on the monophyly of Euryporus and triggered this study.
Examination of the relevant types made the misplacement of all three "exotic" species in Euryporus immediately obvious. But while the correct identity of E. argentatus and E. warisensis as members of the genera Tympanophorus Nordmann, 1837 andHesperus Fauvel, 1874, respectively, also became clear, proper classification of E. multicavus faced a problem of poor generic limits in the subtribes Philonthina and Anisolinina, and even a problem of blurred limit between these subtribes (Schillhammer 2004). In such circumstances, a broader phylogenetic analysis embracing relevant lineages from these and related subtribes of Staphylinini would be required. For the poorly known fauna of New Guinea and adjacent regions such analysis was impossible without prior extensive taxonomic study of many species, which was far beyond the scope and goals of this paper. Therefore, E. multicavus is explicitly removed from Euryporus but left as incertae sedis within Staphylinini pending further study.

Material and methods
The paper is based on the material from the following institutions: Labels of the examined types are quoted verbatim; data from each label are separated by a slash [/]. Photos in Figs 3 and 8 were taken by the author with an MP-E 65 mm lens for Canon EOS 40D; those in Figs 2, 4-7, and 9-11 were taken by Ken Puliafico (Copenhagen) with a Leica DFC 420 camera attached to a Leica MZ16A microscope with the aid of Leica Application Suite (Leica Microsystems, 2003-2007 and Automontage Pro (Synoptics Ltd, 1997-2004. The photo in Fig. 1 was produced and kindly provided by Harald Schillhammer (Vienna).

Genus
As a result, the genus Euryporus included six species before this study (e.g., Herman 2001). Of them the type species E. picipes and two other West Palearctic species, E. aeneiventris, and E. princeps, are very similar to each other and rather well-known (e.g., Coiffait 1978, Assing andSchülke 2012). Examination of the type material for the "exotic" E. argentatus, E. multicavus and E. warisensis led to their exclusion from Euryporus as explained below.
Updated diagnosis, composition and phylogenetic relationships. Without the excluded taxa (see below), Euryporus comprises three species very similar to each other: E. picipes (Paykull, 1800) widely distributed in Europe (Fig. 1); the West Mediterranean E. aeneiventris Lucas, 1846;and E. princeps Wollaston, 1864, endemic to the Canary Islands. Male genitalia of all species were illustrated in Coiffait (1978).
Among other genera of the subtribe Quediina, Euryporus can be distinguished by the following combination of characters: fully developed infraorbital ridges; mandibles elongate with broad basal part but narrow and sharp apical portion; last segment of maxillary palps fusiform, slightly setose; last segment of labial palps enlarged, apically obliquely truncated, densely setose; first antennal segment elongate, as long as second and third antennal segments together; anterior tarsi narrow, not enlarged in both sexes; apical margin of abdominal sternite VIII in both sexes concave, in male without median incision. Other recent descriptions and synopses of the genus can be found in Coiffait (1978) and Assing and Schülke (2012).   dius Casey, 1915, Hemiquedius Casey, 1915, Anchocerus Fauvel, 1905, Australotarsius Solodovnikov et Newton, 2009, and Acylophorus Nordmann, 1837(Solodovnikov and Schomann 2009; but see additional remarks about alternative hypotheses in Solodovnikov and Newton 2009). Although Euryporus was not included in the molecular study of Chatzimanolis et al. (2010) because of unavailable DNA-quality material, the above mentioned lineage was recovered as monophyletic in the Bayesian analysis of that study. The larvae-based analysis (Pietrykowska-Tudruj et al. 2012) was inconclusive as far as sister relationships of Euryporus is concerned.
It is noteworthy that long after the description of E. argentatus, Fauvel (1902) did recognize the correct affiliation of that species. In a short note on page 42 he mentioned "Tympanophorus argentatus Fvl. (rugosus Waterh.)", apparently meaning a synonymy of his species with T. rugosus (C. Waterhouse, 1884). This so vaguely annotated transfer of E. argentatus to Tympanophorus was overlooked by later authors. For example Herman (2001) lists both Euryporus argentatus Fauvel, 1881 as a valid species and "Tympanophorus argentatus Fauvel", erroneously, as nomen nudum. Synonymy of Tympanophorus argentatus (Fauvel, 1881) and T. rugosus (C. Waterhouse, 1884) remains to be verified. (Last, 1987), comb. n. http://species-id.net/wiki/Hesperus_warisensis  Although E. warisensis is strikingly different from the Palearctic Euryporus (cf. Figs  1 and 3), Last (1987) did not provide any justification for his generic placement. Based on the structure of head sutures (rudimentary infraorbital ridges, Fig. 5; present dorsal basal ridge on the neck), prothorax (laterally visible hypomera; superior marginal line turning downwards before anterior angles of pronotum, Fig. 6); anterior angles of pronotum not strongly protruding over anterior margin of prothorax), legs (lacking empodial setae) and other characters, E. warisensis is clearly not congeneric with Euryporus and in fact belongs to the subtribe Philonthina.

Hesperus warisensis
Because of its rather elongate mandibles and maxillary palps (Fig. 5), as well as habitus resemblance, E. warisensis could be associated with some species of Hesperus from New Guinea like H. raynori Last, 1987 and others. As pointed out in Schil- lhammer (2002) about Hesperus ["…this genus is a dumping ground for species matching a particular set of characters which can hardly suffice to justify a monogeneric treatment"], and demonstrated in the phylogenetic analysis (Li and Zhou 2011), this genus is not a monophyletic group and needs a revision. In such circumstances placement of E. warisensis in Hesperus is a practical solution pending further study. As far as I am aware (and personal communication of H. Schillhammer), the enlarged apical labial palpomeres of E. warisensis easily distinguish this species from any other known species of Hesperus.
It is noteworthy that on the left side of the pronotum (Fig. 7) the holotype of Hesperus warisensis displays a "fake" superior line extended towards anterior angles of pronotum, while the right side has no such structure (Fig. 6). Presumably, the left side of the pronotum in the holotype displays a slight teratology. Last, 1980,  Comments. As in the above described case, Euryporus multicavus is strikingly different from the Palearctic Euryporus in habitus (cf. Figs 1 and 8), but Last (1980) did not explain why his species was assigned to that genus. Based on the structure of head (rudimentary infraorbital ridges (Fig. 11); present dorsal basal ridge on the neck), prothorax (superior marginal line inflected inwards under anterior angles of pronotum; pronotal hypomera visible from lateral view; anterior angles of pronotum not strongly protruding over anterior margin of pronthorax), legs (lacking empodial setae) and other characters, it is clear that E. multicavus is not congeneric with Euryporus and even does not belong to the subtribe Quediina. On the other hand, the combination of characters of that species does not allow its unambiguous placement in any of the currently recognized subtribes of Staphylinini.

Euryporus multicavus
Because of the short and stout labial palps with dilated last segment, shape of the mandibles (Fig. 11), strongly foveate surface of the apical abdominal segments, and the overall habitus (Fig. 8) remotely resembling Tympanophorus, I assume that "Euryporus" multicavus is phylogenetically close to the Tympanophorus-lineage of the subtribe Anisolinina (as defined in Schillhammer 2004). But the absence of the elevated ridge on the mesosternum, absence of empodial setae, sexually dimorphic sternite VII (with slight medio-apical incision in male) and strongly reduced para- Figures 8-11. "Euryporus" multicavus, paratype: 8 habitus 9 body in ventral view 10 aedeagus in parameral view 11 head in ventral view. mere of the aedeagus (Fig. 10), cast doubts on such affinity. At least the absence of empodial setae and extremely reduced paramere of the aedeagus are shared by "Euryporus" multicavus with several species from New Guinea described in the genera Philonthus and Hesperus. But, except Hesperus warisensis moved to that genus here, none of those species have robust and dilated labial palpi, and all of them differ from "Euryporus" multicavus in other details. It is possible that "Euryporus" multicavus represents a new genus whose description must be postponed until a more inclusive phylogenetic study of relevant lineages is performed. Such study should be based not only on an extensive taxonomic revision of the hitherto poorly described relevant species but also include additional material from the collections of Staphylinini from New Guinea and adjacent regions, which I am aware of and which have remained largely untouched by modern workers.