Revision of the rove beetle genus Antimerus (Coleoptera, Staphylinidae, Staphylininae), a puzzling endemic Australian lineage of the tribe Staphylinini

Abstract The genus Antimerus Fauvel, 1878, endemic to eastern Australia and Tasmania and a phylogenetically enigmatic member of the large rove beetle tribe Staphylinini, is revised. The genus and each of its four previously known species are redescribed, and a lectotype is designated for Antimerus punctipennis Lea, 1906. Five species are described as new: Antimerus metallicus sp. n., Antimerus jamesrodmani sp. n., Antimerus gracilis sp. n., Antimerus bellus sp. n. and Antimerus monteithi sp. n., so that the number of known species in this genus now totals nine. For the first time Antimerus larvae are described, tentatively identified as Antimerus smaragdinus Fauvel, 1878, Antimerus punctipennis and Antimerus metallicus. Available distributional and bionomic data are provided for each species and summarized in the discussion. Adult and larval morphology of Antimerus and its distribution patterns are discussed in the broader context of new data on the evolution of the entire tribe Staphylinini, and with respect to the formation of the Australian fauna of this tribe. The phylogenetic position of Antimerus within Staphylinini remains unresolved pending a targeted formal study. However, a majority of currently available data suggests that it could be a basal member of the recently recovered monophyletic clade of Staphylinini tentatively called “Staphylinini propria”.


Introduction
In recent years the rove beetle tribe Staphylinini has been a subject of focused morphology-based (Solodovnikov and Newton 2005;Solodovnikov 2006;Solodovnikov and Schomann 2009;Solodovnikov et al., unpublished data) and molecular (Chatzimanolis et al. 2010) phylogenetic studies aimed at producing a consistent, monophyly-based framework for a badly needed new classifi cation of this tribe. Overall, these studies have recovered the following phylogenetic pattern for the tribe: A few "Quediine-looking" genera (e.g., Valdiviodes Smetana, 1981, Astrapaeus Gravenhorst, 1802; all now in the conventional subtribe Quediina) form relictual basal lineages of Staphylinini. Some of these lineages gave rise to the species-rich "northern Quediina" and "southern Quediina" clades. "Northern Quediina" primarily consist of the north temperate species of Quedius Stephens, 1829 (currently a polyphyletic genus, for details see Solodovnikov 2006) and related genera (e.g., Indoquedius Blackwelder, 1952, Quetarsius Smetana, 1996. "Southern Quediina" is a lineage consisting of the south temperate species of Quedius (many of which occur in Australia), some south temperate genera of Quediina (e.g., Loncovilius Germain, 1903, Cheilocolpus Solier, 1849, Quediomimus Cameron, 1948, global Heterothops Stephens, 1829 (all currently in Quediina) and Atanygnathus Jakobson, 1909 (member of the currently monotypic subtribe Tanygnathinina), as well as the current subtribe Amblyopinina. Another species-rich and robust clade tentatively called "Staphylinini propria" (Chatzimanolis et al. 2010) includes the current subtribes Staphylinina, Philonthina, Xanthopygina and Anisolinina. With only minor exceptions, the current subtribes Staphylinina and Philonthina seem to be largely monophyletic. Monophyly of the current subtribes Xanthopygina and Anisolinina, on the contrary, was questioned. Only the Neotropical core of Xanthopygina seems preliminarily to form a monophyletic group, and the composition and affi nities of Anisolinina seem to be even more doubtful. With the introduction of these new phylogenetic data, sister-group relationships of several genera of Staphylinini which were traditionally either incertae sedis within Staphylinini, or only tentatively assigned to one of its formal subtribes, have been clarifi ed.
However, there are still a number of genera of Staphylinini for which phylogenetic affi nities within the tribe are completely unclear, and the genus Antimerus, the subject of this paper, is one of them. It was originally based on a single new species, Antimerus smaragdinus Fauvel, 1878, from southeastern Australia (Fig. 11), and placed in the staphylinine group Quediini close to the Japanese genus Algon Sharp, 1874 (Fauvel 1878). A further three species from eastern Australia were added by Lea (1906Lea ( , 1925, two of them with doubts about their generic assignment, but without further comment on the placement of the genus. Th e genus remained in the tribe Quediini or subtribe Quediina (of Staphylinini) in the Coleopterorum Catalogus (Bernhauer and Schubert 1916: 410;Scheerpeltz 1933Scheerpeltz : 1420 and in Blackwelder (1952: 57). In the most recent printed world catalog of Staphylinidae (Herman 2001: 165, 3571), the genus appears instead in the subtribe Xanthopygina, without comment. Th is new subtribal assignment for Antimerus was consistent with redefi nitions of Quediina, Xanthopygina and some other subtribes of Staphylinini by Smetana (1977Smetana ( , 1985 and Smetana and Davies (2000), although Antimerus was not specifi cally mentioned in those works. In the Field Museum-based on-line database of the genus-group names of Staphylinoidea (Newton and Th ayer 2005a) Antimerus, instead, is listed as Staphylinini incertae sedis.
Of all these recent papers cited above, Antimerus was included in a formal analysis only in Solodovnikov (2006), where its position was resolved with a high degree of ambiguity. Th at analysis implies two alternative hypotheses: either Antimerus is a very basal and ancient lineage of Staphylinini, similar to an enigmatic Australian endemic Lonia Strand, 1943(Fig. 6a in Solodovnikov 2006; or, like a puzzling genus Algon, it is an isolated, presumably basal, member of "Staphylinini propria", however not fi tting any of its formal subtribes (Fig. 6b in Solodovnikov 2006). Nevertheless, that and other exploratory analyses (Solodovnikov, unpublished) clearly indicate that Antimerus does not belong either to "northern Quediina" where the type species of the formal subtribe Quediina belongs, or to "southern Quediina" that constitute the largest part of the Australian fauna of Staphylinini. Also, it does not seem to be linked to the core (Neotropical species only) of the subtribe Xanthopygina.
At the local (Australian) scale, the biogeographic history of such odd genera as Antimerus (as well as some others, for example Lonia Strand, 1943 (Fig. 20) or Australotarsius Solodovnikov & Newton, 2009) is of high interest. Although there have been no rigorous attempts to time-calibrate the discussed newly emerging phylogenetic pattern of Staphylinini, the hitherto available phylogenetic (listed above) and paleontological data on Staphylinidae (Solodovnikov, unpublished) make it plausible to date the origin of Staphylinini back to Late Jurassic or Early Cretaceous, and to associate divergence between "northern Quediina" and "southern Quediina" with separation of Gondwana and Laurasia. Considering the recent distribution pattern of the group, it also seems plausible to assume that the origin and initial diversifi cation of the younger "Staphylinini propria" clade took place in the northern hemisphere landmasses, with subsequent dispersal of some of its lineages southwards. Within such a framework, it appears quite evident that the Australian fauna of Staphylinini (for a complete catalogue of taxa see Newton and Th ayer 2005b) predominantly consists of species belonging to the "southern Quediina" lineage, which have been evolving in this continent in situ for a long time (meaning the "continent" in a broader Gondwanan sense than modern Australia only). And it is also evident that the Australian fauna is very depauperate as far as the "northern Quediina" and "Staphylinini propria" are concerned. Only a small fraction of the genera and species of these alien lineages were able to disperse to Australia, either naturally or via human-induced introduction. Whether Antimerus is an ancient relict in Australia, or a younger arrival to this continent from the north, remains to be understood.
As a step towards a better overall knowledge of Antimerus, this really peculiar element of the Australian fauna of Staphylinini, we provide here its taxonomic revision, including description of fi ve new species (out of nine species in total) and description of its presumed larva.

Materials and methods
Th is paper is based on the study of specimens using high quality dissecting microscopes. Material is kept in several institutions, listed below (with names of responsible collection personnel) and cited in the "Material examined" sections by the indicated coden or name. Beetles were examined mainly as pinned dry specimens, but a few were macerated in 10% KOH, rinsed, disarticulated and examined as wet preparations in glycerin to produce a more detailed generic redescription. Th e same wet procedure was applied for a study of alcohol-preserved larvae, and for beetle aedeagi. All line illustrations were made using a camera lucida. All measurements are given in millimeters; they were made with an ocular linear micrometer and abbreviated as explained below. All specimens were databased at the Field Museum, and most were assigned a unique "FMNH-INS" number (if no existing unique number was present). Th ese numbers are cited in the "Material examined" sections only for holotypes, lectotype, and paratypes of rare species. Specimen labels for primary types (holotypes, lectotype) are cited exactly in quotes, with a slash (/) separating lines; data for other specimens are generally cited as given on labels, except that collecting dates are standardized in the formula day.month.year, using lower-case Roman numerals for month. Data not present on original labels but added for clarity or amplifi cation (e.g., coordinates) are given in square brackets [ ].

Measurements and their abbreviations
HL -head length (from apex of clypeus to neck constriction); HW -head width (maximal, including eyes); PL -pronotum length (along median line); PW -pronotum width (maximal); EL -elytral length (from humerus to most distal apical margin; best taken from lateral view of the elytron); EW -combined width of both elytra (maximal, elytra closed along suture). Th e total length of the body given in the descriptions was measured from the tip of the labrum to the tip of the abdomen.
Head transverse; neck about half as wide as head, distinct at sides but not or indistinctly marked dorsally; eye large, occupying more than half of side of head; temple short, hind angle of head broadly rounded or indistinct; antenna slender, longer than head width, increasingly densely pubescent from about antennomere 6 to apex; labrum ( Fig. 1) very short and wide, about 2/3 as wide as head, with sclerotized anterior margin and acute median emargination; mandible ( Fig. 3) long, slender, falcate, about as long as head excluding neck, with narrow bladelike medial edge along apical half or more, edentate or at most with one small tooth along medial edge of basal half, with  short abruptly expanded base, and without prostheca (except A. auricomus with very slender prostheca no longer than width of mandible at base); maxillary (Fig. 4) and labial (Fig. 2) palps with robust, elongate apical palpomeres that are about as wide or wider than more basal palpomeres and with abruptly truncate apices; galea and lacinia  densely setose; paraglossa very long, fi ngerlike, with comb of strong setae along mesial edge; glossae short, densely setose; prementum small, transverse; mentum transverse, broadly emarginate at apex; gular sutures ( Fig. 6) complete, closely approximate through much of length; postgenal (Fig. 6, pg) and ventral basal (Fig. 6, vb) ridges well-developed, nuchal ridge absent, infraorbital ridge (Fig. 6, io) rudimental, short. Pronotum (Fig. 5) subquadrate to strongly transverse; superior line of hypomeron continued onto anterior margin, visible from above (except in A. posttibialis where it is defl exed ventrad and not visible from above in apical fourth); inferior line of hypomeron complete except interrupted at coxal articulation, or more or less obsolete; hypomeron with large triangular partly translucent post-coxal process; hypomeron completely visible from side (except in Antimerus monteithi sp. n. where it is infl exed and completely hidden in lateral view except for apex of postcoxal process); notosternal suture ( Fig. 5, ns) complete, distinct; prosternum short, transverse, its anterior edge laterally not forming an abrupt angle with hypomeron; procoxal cavities largely closed behind by very large mesothoracic spiracles (Fig. 5, spi) plus a smaller irregular median sclerotized area (Fig. 5,msa) between the spiracles.
Scutellum large, triangular, with two transverse subbasal carinae. Elytron without epipleural ridge; elytra together about as long as wide. Hind wings fully developed and functional, each with completely separate MP4 and CuA veins. Mesocoxae contiguous, mesocoxal cavities delimited anteriorly and posteriorly by carinae (Fig. 7). All tarsi 5-segmented, tarsomeres 1-4 of all legs of both sexes more or less broad, basal tarsomeres of front legs as wide as or wider than width of protibia, those of other segments narrower than width of corresponding tibiae; tarsomeres 1-4 of all legs with dense brushes of tenent setae ventrally; tarsal claws simple, empodium with pair of setae that are shorter than claws.
Abdomen without prototergal gland (Fig. 8), apparently without eversible defensive glands posterior to tergum VIII. Tergites II-VIII and sternites III-VIII each with a single subbasal carina that is curved posteriad at sides (behind spiracle on tergites); tergites III-VIII also with short oblique anterolateral carina before spiracle. Segments III-VII with two pairs of laterotergites each, the dorsal laterotergites on III-VI each with a subbasal carina. Intersegmental membranes between segments III-VII attached preapically to preceding segment, with irregular or quadrangular, more or less rounded sclerites occupying less than 70% of membrane surface. Sternum VIII with slight to moderate apical emargination in male, with no or more shallow emargination in female; sexual dimorphism otherwise restricted to genital segment and associated genitalia.
Genital segment of both sexes with triangular tergum X which widely separates lateral tergites IX dorsally, and each lateral tergite IX produced into hollow, fi ngerlike, apically obtuse or rounded process. Male sternite IX entire, more or less symmetrical or with base slightly more produced anteriad on left side (Fig. 7a). Aedeagus  with parameres fused into a single large apically emarginate lobe which bears dense fi eld of dark peg setae facing median lobe, and at least 4 pairs of apical setae; median lobe elongate, tubular for most of length with basal membranous area bearing pair of fl aps, apex more or less triangularly produced to extend slightly beyond apex of paramere; internal sac with large well sclerotized copulatory sclerite that abuts apex of median lobe when internal sac everted, and pair of more distal membranous or partly sclerotized lobes; aedeagus in repose in abdomen with paramere facing left side of beetle. Female without median ventral sclerite, ovipositor consisting of paired proximal and distal gonocoxites, styli apparently absent; spermatheca apparently not sclerotized. Distribution and bionomics. (Figs 55,56) All hitherto known species of Antimerus (see below) are confi ned to the moist forests of the coastal hills and mountain ranges of eastern Australia, from northern Queensland to Victoria, South Australia and Tasmania. However, there is a signifi cant gap in this arc: the genus is not known to occur for a long stretch in central and southern Queensland (Fig.  55, A-C). Th is seems to be not a sampling artifact, but a real disjunction coinciding with the gap in the distribution of moist forests in eastern Australia (Groves 1994). Apart from evidence that species of Antimerus are apparently confi ned to forests (e.g., Fig. 56), very little is known about their microhabitat preferences, which seem to vary from one species to another (see species details below). Available label data, our own collecting experience, and morphology of the genus (large eyes, expanded tarsi of all legs) suggest that at least some species of the genus are diurnal and more or less arboreal. Arboreality may explain their rarity in collections, which have been mostly obtained by methods targeting microhabitats on or near the ground.
Comparison. In Australia, Antimerus can be distinguished from any other genus of the tribe Staphylinini by the following combination of characters: relatively large body size (13-20 mm); relatively long falcate mandibles without distinct teeth internally (except small tooth on left mandible only in two species); defl exed hypomera of pronotum visible in lateral view (except A. monteithi, concealed); tarsomeres 1-4 of all legs in both sexes broad and bearing tenent setae ventrally; and one pair of empodial setae on all tarsi. Th e only sympatric genus likely to be confused with Antimerus is Lonia which has distinct mandibular teeth internally and simple meso-and metatarsi (Fig. 20).

1.
Disc of head and pronotum moderately densely punctate and setose; body vestiture including pale (white or yellow) as well as dark setae, with dense patches of pale setae on at least some abdominal terga (  Head and pronotum metallic blue with purple refl ection, with dense microsculpture resembling "fi ngerprint whorl", with moderately dense punctuation and pale pubescence; elytra brown with dark spot in the middle of disc, with dense punctuation and dense pubescence; abdomen dark brown to black, third and fourth tergites (fi rst and second visible) with patches of dense silver pubescence laterally, fi fth tergite (third visible) with black pubescence, sixth to eight tergites (fourth to sixth visible) with dense yellow pubescence; appendages brown. Body elongate, slender.
Head slightly wider than long, with tempora rapidly narrowing towards neck so that posterior angles of head indistinct; tempora as long as eye (in lateral view). Left mandible with very small but distinct tooth in the middle of its internal edge; right mandible with even smaller tooth in the same position. Antennae moderately long, with antennomeres VIII-X about as long as wide, not transverse.
Pronotum about as long as wide and as wide as head, widest before (anterior) to its middle; pronotal anterior angles distinct, posterior broadly rounded; hypomera not infl exed, visible from lateral view.
Wings well developed. Abdominal tergites III-VI (fi rst to fourth visible) with deep transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.
Male . Aedeagus with relatively wide (wider than median lobe in dorsal or ventral view) paramere, which is slightly notched at the apex. Sclerotized piece of internal sac triangle-shaped.
Comparison. Among all other species of the genus, Antimerus auricomus can be easily recognized by the very characteristic coloration of the body: metallic blue with purple forebody, pale brown elytra with darker spot, and black abdomen with multicolored pubescence.
Distribution and bionomics. Antimerus auricomus is known from several localities in eastern Australia, in southern Queensland and northern New South Wales (Fig. 55,C,circles). Specimens with more complete label data were collected in subtropical rainforest from the canopy of the tree Argyrodendron actinophyllum Edlin (Sterculiaceae) 25 m above ground (see Basset 1991), and on the trunk of a Eucalyptus tree.

Antimerus posttibialis
Body black, without distinct metallic refl ection; elytra near their apical margin, and legs slightly paler; two to three basal segments of antennae pale brown, rest of antennae yellowish. Head, pronotum and elytra with moderately dense punctuation and pale, yellowish pubescence, their surfaces at interspaces with microsculpture of mostly transverse waves. Fifth to eighth abdominal tergites (third to sixth visible) with patches of more or less dense silver pubescence. Body elongate, relatively slender.
Head slightly wider than long, with tempora gradually tapering to weakly defi ned neck constriction, so that posterior angles of head indistinct; tempora as long as eye (in lateral view). Left mandible with very small but distinct tooth in the middle of its internal edge; right mandible without such tooth. Antennae moderately long, with antennomeres VIII-X about as long as wide, not transverse.
Pronotum about as long as wide and as wide as head, its lateral sides gradually diverging from base to pronotal anterior margin, and slightly converging very near to anterior angles; anterior angles very distinct, posterior slightly distinct. Pronotal hypomera not infl exed, visible from lateral view.
Elytron elongate, distinctly longer than pronotum. Wings well developed. Abdominal tergites III-VI (fi rst to fourth visible) with deep transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.
Male . Aedeagus with paramere as wide as median lobe (in dorsal or ventral view); paramere strongly notched at the apex. Sclerotized piece of internal sac with shape of three-lobed structure.
Comparison. From all other species of the genus, Antimerus posttibialis can be easily recognized by the combination of the black, non-metallic coloration of the body covered by silver pubescence, and patches of dense silver hairs on the abdominal tergites V-VIII (third to sixth visible).
Distribution and bionomics. Antimerus posttibialis is known from only a few specimens from two localities in northern Queensland, near the eastern coast of Australia ( Fig. 55, C, triangles). Habitat data are recorded for only one specimen, which was collected in the rainforest at 770 m elevation by low scale pyrethrum fogging of tree trunks and rocks.
Notes on type material. Th ere is a clear indication in the original description that the latter was based on a single specimen ("Queensland: Kuranda (F.P. Dodd). Type (unique), I. 12698", which was unambiguously located at SAM and interpreted as holotype. Four specimens from the same locality in ANIC, BMNH and FMNH are labeled variously as "type", "cotype" or "paratype" and may have been collected with the type, but were evidently not part of the original type series. Head, pronotum and elytra metallic green, bluish or purple, abdomen black with slight metallic refl ection; often head and pronotum metallic green but elytra with different (bluish or purple) refl ection. Disc of head and pronotum without punctuation or pubescence, their surfaces with reticulate microsculpture forming isodiametric mesh. Elytra with dense punctuation and black pubescence, interspaces with reticulate microsculpture. Head, pronotum and elytra somewhat dull, elytra glossy. Appendages brownish-black, mouthparts and apical parts of antennae paler.

Antimerus smaragdinus
Head transverse, considerably wider than long, with rounded but distinct hind angles, tempora slightly shorter than eye (in lateral view). Antennae moderately long, with antennomeres VIII-X about as long as wide, not transverse.
Pronotum slightly wider than long, slightly wider than head, widest along middle third of its length, slightly converging anteriad and posteriad; pronotal anterior angles rounded but distinct, posterior broadly rounded, poorly distinct. Pronotal hypomera not infl exed, visible from lateral view.
Abdominal tergites IV-VI (second to fourth visible) with shallow transverse impression in basal part, and with vague but distinct midlongitudinal keel-like elevations; tergite VII (fi fth visible) with whitish seam at apical margin.
Male . Aedeagus with paramere narrowing apically; apical half of the paramere narrower than median lobe, its apex slightly notched (in dorsal, parameral view).
Comparison. Antimerus smaragdinus is most similar to its sister species, A. punctipennis, from which it diff ers externally in the uniformly colored elytra (no pale humeral spots) and presence of midlongitudinal elevations on the abdominal tergites IV-VI (second to fourth visible). Aedeagi of both A. smaragdinus and A. punctipennis are very similar, the former however having slightly more obtuse apex of the paramere (in dorsal or ventral view).
Distribution and bionomics. Antimerus smaragdinus is confi ned to the southeastern corner of Australia, including northwestern Tasmania (Fig. 55, A, triangles). Distribution on the mainland covers most of Victoria, the southeast corner of South Australia and southeast corner of New South Wales. It is the only species of the genus which occurs in the south of Australia, being totally allopatric to any other species of Antimerus but abutting the distribution of its sister species A. punctipennis. Specimens of A. smaragdinus with associated bionomic information were collected in wet to dry sclerophyll forests of various types, between 80 and 1000 m elevation by sifting leaf litter, by carrion-baited and unbaited pitfall traps, in fl ight traps and by hand collecting.

Antimerus punctipennis
Head, pronotum and elytra metallic green, brassy or metallic purplish, abdomen dark brown to black, without strong metallic refl ection, often with pale brown apical margin of tergite VII (fi fth visible) and (or) pale brown apical part of tergite IV (second visible); humeri of elytra laterally (often) and stripe along elytral suture (seldom) pale brown; appendages brown. Disc of head and pronotum without punctuation or pubescence, their surfaces with reticulate microsculpture forming isodiametric mesh. Elytra with dense punctuation and black pubescence, interspaces with weak irregular (not isodiametric) microsculpture. Head, pronotum and elytra somewhat dull, elytra glossy.
Head considerably wider than long, with rounded but very distinct hind angles, tempora slightly shorter than eye (in lateral view). Antennae moderately long, with antennomeres VIII-X about as long as wide, not transverse.
Pronotum slightly wider than long, about as wide as head; pronotal anterior angles rounded but distinct, posterior broadly rounded, poorly distinct; pronotum widest along middle third of its length, slightly converging anteriad and posteriad. Pronotal hypomera not infl exed, visible from lateral view.
Elytron elongate, longer than pronotum. Wings well developed. Abdominal tergites IV-VI (second to fourth visible) with very shallow transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin. Abdominal terga without vague longitudinal elevation along midline.
Comparison. Antimerus punctipennis is most similar to its sister species, A. smaragdinus, from which it diff ers externally in the presence of brownish humeral spots on the elytra and absence of vague midlongitudinal elevations on abdominal tergites IV-VI (second to fourth visible). Aedeagi of both species are very similar, the former however having a slightly more pointed apex of the paramere (in dorsal or ventral view, cf. Figs 32 and 29). For diff erences of A. punctipennis from A. metallicus, another very similar species, see the latter below.
Distribution and bionomics. Antimerus punctipennis is the most common species of the genus, distributed in eastern Australia from the south of Queensland to the south of New South Wales. In the southeastern corner of New South Wales its distribution abuts that of A. smaragdinus (Fig. 55, A, squares -A. punctipennis, triangles -A. smaragdinus), but these sister species are apparently completely allopatric. All adult specimens of A. punctipennis were collected in various types of temperate to tropical forests, especially in rainforests but also in wet to dry sclerophyll forests, at elevations from 80 to 1350 m, mostly on the ground, by pitfall traps or by sifting leaf litter. Some specimens came to fl ight intercept traps (e.g., Fig. 56), Malaise traps, or were hand collected from logs and by beating tree branches; two were collected while fl ying to shaded rocks at the edge of a clearing at midday. All presumed larvae of this species (see below) were collected from forest leaf litter. Th e available sample suggests that A. punctipennis is mostly confi ned to living on the ground with the ability to climb tree trunks and possibly branches, or other vegetation.
Head considerably wider than long, with broadly rounded hind angles, tempora distinctly shorter than eye (in lateral view). Antennae moderately long, with antennomeres VIII-X about as long as wide, not transverse.
Pronotum slightly wider than long, only slightly narrower than head; pronotal anterior angles rounded but distinct, posterior angles also distinct although more rounded; pronotum widest before (anterior to) its middle, converging anteriad and posteriad. Pronotal hypomera not infl exed, visible from lateral view.
Elytron elongate, longer than pronotum. Wings well developed. Abdominal tergites IV-VI (second to fi fth visible) with moderately deep transverse impression in basal part and slightly elevated obtuse median keels across these impressions; tergite VII (fi fth visible) with whitish seam at apical margin.
Comparison. Antimerus metallicus is very similar to A. punctipennis and A. smaragdinus, but diff ers well from both of them in having transverse wavy (rather than reticulate) microsculpture of the disc of the head and pronotum, these bodyparts therefore appearing more glossy. Th e shape of the aedeagus in A. metallicus is practically identical to that of A. punctipennis (hence, Figs 30-32 can serve for both) except for a subtle diff erence in the shape of the sclerotized piece of the internal sac (cf. Figs 33 and 34).
Distribution and bionomics. Antimerus metallicus is confi ned to northern Queensland (Fig. 55, A, circles). Its distribution is well separated from those of the closely related A. punctipennis and A. smaragdinus. Adults of A. metallicus were collected in rainforest and wet sclerophyll forest, mostly in highlands between 700 and 1300 m elevation, and mostly by pitfall traps or by fl ight intercept traps. Some specimens, including two presumed larvae, were sifted from leaf litter, some were hand collected from the ground, and one specimen came to a Malaise trap.

Antimerus jamesrodmani
Head and pronotum metallic blue with purple refl ection, very glossy; elytra red with metallic refl ection; abdomen dark brown to black, with weak metallic refl ection, antennae and tarsi paler, brown. Disc of head and pronotum without punctuation or pubescence, their surfaces with microsculpture of transverse waves and micropunctuation. Elytra with sparse punctuation bearing brown to black pubescence, interspaces without distinct microsculpture. Abdomen moderately densely punctuated, with brown to black pubescence.
Head wider than long; tempora tapered towards relatively narrow neck, forming broadly rounded, poorly distinct hind angles, about as long as eye (in lateral view); neck delimited from head dorsally by very fi ne groove. Antennae with antennomeres VIII-X distinctly wider than long, transverse.
Pronotum slightly wider than long, as wide as head; pronotal anterior and posterior angles rounded but distinct; pronotum widest in its middle, converging more strongly anteriad than posteriad. Pronotal hypomera infl exed, not visible from lateral view except for its translucent postcoxal process.
Elytron elongate, longer than pronotum. Wings well developed. Abdominal tergites IV-VI (second to fourth visible) with moderately deep transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.
Comparison. Antimerus jamesrodmani is most similar to A. bellus and A. gracilis. From both of them A. jamesrodmani diff ers in having red elytra and the neck delimited from the head dorsally by very fi ne groove (rather than not delimited). From A. bellus additionally it diff ers in having slightly more distinct hind angles of the head. Aedeagi of A. jamesrodmani and A. bellus are very similar and diff er slightly in the shape of the sclerotized piece of the internal sac. Also, unlike that in A. bellus, the median lobe in A. jamesrodmani lacks lateral carinae on its parameral side near apex (in lateral view; cf. Figs 35 and 38, carina indicated by "c"; sclerotized piece indicated by arrow).
Distribution and bionomics. Antimerus jamesrodmani is known only from the type locality in southeastern Queensland (Fig. 55, B, triangle). All known specimens were collected in subtropical rainforest from the canopy of the tree Argyrodendron actinophyllum Edlin (Sterculiaceae) 25 m above ground (see Basset 1991), suggesting an arboreal life style for this species.
Etymology. It is our pleasure to dedicate this noticeable rove beetle species to Dr. James Rodman, who promoted and then, for a number of years, managed the "Partnership of Enhancing Expertise in Taxonomy" (PEET) program at the National Science Foundation of the United States. Th e PEET funding greatly facilitates systematic exploration of poorly known groups of organisms on a world basis and provides unique opportunities for young systematists to develop their own careers. In particular, our taxonomic exploration of the poorly known Australian Staphylinidae greatly benefi ted from the PEET program. Head, pronotum and elytra metallic blue with purplish refl ection, very glossy; abdomen and appendages dark brown. Disc of head and pronotum without punctuation or pubescence, their surfaces with microsculpture of transverse waves and faint micropunctuation. Elytra with sparse punctuation and brown to black pubescence, interspaces without distinct microsculpture. Abdomen moderately densely punctuated, without distinct metallic refl ection, with brown to black pubescence.

Antimerus bellus
Head wider than long, with tempora strongly tapered towards relatively narrow neck, about as long as eye (in lateral view); neck not delimited from head dorsally. Antennae with antennomeres VIII-X distinctly wider than long, transverse.
Pronotum slightly wider than long, as wide as head; pronotal anterior and posterior angles rounded but distinct; pronotum widest behind its middle in the area of its posterior angles, its sides, from posterior angles to middle very gradually and anterior from middle, more strongly, converging anteriad. Pronotal hypomera infl exed, not visible from lateral view except for its translucent postcoxal process,.
Abdominal tergites III-V (fi rst to third visible) with moderately deep transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.

Comparison. Antimerus bellus is most similar to A. jamesrodmani and A. gracilis.
From A. jamesrodmani it diff ers in the shape of the head which has more broadly rounded, indistinct hind angles, and in the coloration of the elytra, which are not red and have a stronger metallic refl ection similar to that of head and pronotum. Aedeagi of A. bellus and A. jamesrodmani are very similar; for diff erences see "comparison" under the latter species . From A. gracilis, A. bellus diff ers in coloration (cf. Figs 17 and 18) of the body.
Distribution and bionomics. Antimerus bellus is known only from two specimens collected in diff erent localities in eastern New South Wales (Fig. 55, B, circles). No habitat data are available.
Etymology. Th e name of the new species is from the Latin adjective bellus, or beautiful. Head and pronotum metallic green, with slight brassy refl ection, very glossy; elytra, on disc dark brown with bluish metallic refl ection, but at shoulders, in epipleural areas, along suture and apical margins brown, without metallic refl ection; abdomen dark brown except for orange apex (apical part of segment VII and entire segment VIII (fi fth and sixth visible) orange); legs dark brown; antennae paler. Disc of head and pronotum without punctuation or pubescence, their surfaces with microsculpture of transverse waves and faint micropunctuation. Elytra with sparse punctuation and brown to black pubescence, interspaces without distinct microsculpture. Abdomen moderately densely punctuated, without distinct metallic refl ection, with brown to black pubescence.

Antimerus gracilis
Head wider than long, with tempora strongly tapered towards relatively narrow neck, about as long as eye (in lateral view) forming poorly distinct broadly rounded hind angles; neck not delimited from head dorsally. Antennae with antennomeres VI-II-X distinctly wider than long, transverse.
Pronotum about as wide as long, and about as wide as head; pronotal anterior and posterior angles rounded but distinct; pronotum widest in the area of its middle, its sides very gradually converging posteriad, and more strongly converging anteriad. Pronotal hypomera infl exed, but slightly visible from lateral view.
Elytron elongate, longer than pronotum. Wings well developed. Abdominal tergites III-V (fi rst to third visible) with moderately deep transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.
Male unknown.
Comparison. Antimerus gracilis is most similar to A. jamesrodmani, from which it diff ers in coloration (cf . Figs 18 and 16) and in the slightly more pronounced posterior angles of the head. From A. bellus, another similar species, A. gracilis also diff ers in coloration of the body (cf . Figs 18 and 17).
Distribution and bionomics. Antimerus gracilis is known only from the type locality in northeastern Queensland (Fig. 55, B, square). Th e only available specimen was collected by low-scale fogging of trees from the ground, in the forest at the elevation 1325 m.
Etymology. Th e name of the new species is from the Latin adjective gracilis, or slender.  Solodovnikov des. 2006", 1♂ in QM. Paratypes: Lamington N.P., Binna Burra, 18.xi.1982  Head and pronotum black, glossy but without metallic refl ection; elytra bluegreenish, glossy, with strong metallic refl ection; abdomen and appendages dark brown to black. Disc of head and pronotum without punctuation or pubescence, their surfaces with microsculpture of transverse waves and faint micropunctuation. Elytra with irregular, non-setiferous punctuation, glabrous with only a few long black macrosetae; interspaces between punctures without distinct microsculpture. Abdomen densely and moderately coarsely punctate, without metallic refl ection, with brown to black pubescence; interspaces between punctures with distinct transverse microsculpture.

Antimerus monteithi
Head wider than long; tempora about as long as eye (in lateral view) forming distinct broadly rounded hind angles. Antennae with antennomeres VIII-X distinctly wider than long, transverse.
Pronotum distinctly transverse, obviously wider than long and about as wide as head; pronotal posterior and especially anterior angles very distinct; pronotum widest in the area near its posterior angles, gradually narrowing anteriad. Pronotal hypomera strongly infl exed, not visible from lateral view.
Elytron longer than pronotum, about as long as wide. Wings well developed. Abdominal tergites III-V (fi rst to third visible) with slight transverse impression in basal part; tergite VII (fi fth visible) with whitish seam at apical margin.
Male . Aedeagus with paramere slightly narrower than median lobe (in dorsal view), distinctly bilobed; lobes separated by deep narrow incision.
Comparison. Antimerus monteithi is a very distinct species, that can be easily distinguished from any other member of the genus by having completely glabrous elytra and a distinctly transverse pronotum with very distinct anterior angles, giving it a quediine-like appearance.
Distribution and bionomics. Antimerus monteithi is known from four neighboring localities in the border area between southeastern Queensland and northeastern New South Wales (Fig. 55, C, squares). All specimens were taken in the forest at an elevation of 900-1000 m. Two specimens were collected on logs or under tree bark, one by pitfall trap and one at a fl ight intercept trap.
Etymology. We dedicate this species to our friend and colleague Geoff Monteith to acknowledge his great collecting eff ort in Australia, which has made signifi cant material on Staphylinidae from this continent available for study. In particular, he collected the holotype of this peculiar species.

Larvae of Antimerus
Th e life cycle of Antimerus species is unknown, and no immature stages have been described. A very distinctive larval type of Staphylininae of large size but unknown identity has been found in numerous forest litter samples in eastern Australia, from northern Queensland to southern Victoria (Fig. 55), within the general range of various Antimerus species but not in direct association with adults. We attribute these larvae to Antimerus for the following reasons: 1) Th e larvae appear to fall into three size classes, probably representing the usual three instars of known larvae of Staphylininae. Th e largest larvae, presumably of the fi nal instar, are about 16 mm long with heads about 3 mm wide. Th ere are few adult Staphylininae in eastern Australia large enough to belong to these larvae, and most of these belong to genera for which some larvae are known (Creophilus Leach, 1819;Hesperus Fauvel, 1874;Quedius Stephens, 1829, Tasgius Stephens, 1829 and Th yreocephalus Guérin-Méneville, 1844), or in which known species are restricted to northern Queensland (Actinus Fauvel, 1878 andMysolius Fauvel, 1878), leaving only Antimerus species, Lonia regalis (Olliff , 1887) and Australotarsius grandis Solodovnikov & Newton, 2009 as possibilities based on size and distribution. 2) Th e larvae clearly belong to Staphylininae and probably Staphylinini (see description below), but, like Antimerus adults, do not fi t any of the recognized subtribal groups very well. 3) Th e larvae have been found at many of the same localities at which one or more species of adults of Antimerus have been found, and all were found within the known ranges of various Antimerus species. In contrast, adults of Lonia regalis are confi rmed as present only in southern Queensland and northern New South Wales (Fig. 55, D), and are exceedingly rare; to our knowledge, adults have not been collected by anyone since the 1920's. Australotarsius grandis is also known only from a few specimens originating in a few localities in Queensland and New South Wales (Solodovnikov and Newton 2009). 4) Th e larvae apparently represent at least three species, whose distributions correlate approximately with the known distributions of one or more Antimerus species; Lonia is a monobasic genus, and Australotarsius grandis is the only species in that genus which nears the size of Antimerus. For these reasons, the larvae described below are attributed to Antimerus.
Th ese larvae are very similar but not identical. Based on their distributions and characteristics, they apparently represent three species (see provisional key below). Th e Victoria larvae are referred to A. smaragdinus, the only species known from Victoria. Th e Kirrama S.F. larvae are referred to A. metallicus because adults have been collected at the same locality and this is the only common species in northern Queensland. Th e rest are referred to A. punctipennis, the commonest species by far throughout New South Wales and southern Queensland; adults of this species have often been found at the same localities as these larvae. Adults of these three Antimerus species are closely similar and replace one another geographically, so it would not be surprising to fi nd that their larvae are also very similar.

Diagnostic description
Large Staphylininae (length ca. 8-16 mm, head width 1.5-3.0 mm), with large subquadrate well-sclerotized head, much narrower thorax, and fusiform abdomen which at middle may exceed head width in well-fed larvae (Fig. 19). Body surfaces and appendages generally microspinose or microtuberculate and with sparse to fairly dense fi ne simple setae; most macrosetae and many intermediate-sized setae club-shaped with "frayed" or multispinose apices.
Provisional key to Antimerus species (larvae) Figure 56. Habitat of Antimerus. Flight intercept trap in warm temperate rainforest at 1000 m elevation in Border Ranges National Park (near junction of Tweed Range and Brindle Creek Roads), northern New South Wales. Four males of A. punctipennis were collected in this trap and one female found in adjacent leaf litter, in early January. Ten fi rst-instar larvae attributed to this species were found at three nearby sites in the park, in leaf litter of similar or subtropical rainforest, at 600-1050 m elevation, in late Februaryearly March (photo: A.F. Newton).

Comments on larval morphology of Antimerus
Larvae have the general characteristics of Staphylininae, including the unique, large, triangular cervicosternum, and the general characteristics of Staphylinini, including the very elongate pygopod (abdominal segment X), presence of many specialized "frayed" setae on the body, and indications of the derivation of the single stemma from fusion of four stemmata. However, they have several unique features within this subfamily and tribe, including an unsclerotized ligula (reminiscent of Paederinae, and especially the broad ligula of Pinophilus and trilobed ligula of Hyperomma), and the unique feature of fusion of the tarsungulus and tibia of the front leg. Other features of both adults and larvae of Antimerus species are reminiscent of the genus Pinophilus and related genera of Paederinae: Long falcate mandibles, short labrum, short wide head and enlarged "sticky" tarsi of adults, and large quadrangular head, small body and broad ligula of larvae.

Discussion
Revision of all available material of the genus Antimerus, including substantial collections made in recent years, more than doubled the number of species hitherto known for the genus. Still, most of the species are known only from a very limited number of specimens. A presumably arboreal way of life of at least some species of Antimerus, which would make these beetles unlikely to be collected by the most commonly used collecting techniques, allows us to expect the discovery of additional new species, especially among material collected from the forest canopy.
Th e high degree of morphological diversity displayed within the genus Antimerus is also noteworthy. Based on their morphology (especially with reference to the characters used in the key to adults, above), the species of the genus can be arranged into preliminary species groups as follows (groups named after the fi rst-listed species each): 1) auricomus + posttibialis; 2) smaragdinus + punctipennis + metallicus; 3) jamesrodmani + bellus + gracilis; and 4) monteithi. Within each species group, species have a similar morphology and allopatric distributions. Species from diff erent species-groups, on the contrary, are more remote morphologically and the distributions of the entire speciesgroups are largely overlapping. Th ese patterns apparently indicate a long divergence time and dispersal history of these respective lineages within the genus, both lines of evidence pointing to a long existence of the genus as a whole. However, neither the pattern of morphological divergence within this peculiar genus, nor its distribution patterns, can give a precise enough measure of the age of the genus to shed light on the phylogenetic problem outlined in the Introduction (i.e., whether Antimerus is a very basal lineage of Staphylinini, or a younger genus, basal within the "Staphylinini propria" clade.). Th e fact that Antimerus is known to be distributed only in the humid forests of eastern Australia, and missing from those of the southwestern corner of that continent, argues against the possibility of an older, Gondwanan, age for this genus.
(Several genera of the presumably much older, Gondwanan "Austral Quediina" group occur both in the eastern and southwestern parts of Australia). Such a distribution of Antimerus in eastern Australia only is more consistent with the latter assumption, that Antimerus is a basal member of the "Staphylinini propria" clade. As pointed out in the introduction, diverse data suggest that the "Staphylinini propria" clade within Staphylinini originated in the northern hemisphere landmasses in times when those were already separated from Gondwana. Assuming that Antimerus is a member of "Staphylinini propria", it may have colonized Australia from southeast Asia, where subsequently it apparently went extinct. Th is scenario suggests that additional species may yet be discovered in southeast Asia or New Guinea.
Th e newly discovered putative larvae of Antimerus have a very peculiar morphology, suggesting this genus may be even more isolated within Staphylinini than adult morphology suggests. Larval morphology alone is more consistent with the idea that Antimerus is a more ancient lineage, not belonging to the "Staphylinini propria" clade. But too many larval forms of Staphylinini are still unknown to allow any sound conclusions at present. In addition, we interpret many larval features of Antimerus, especially some similarities with larvae of pinophiline Paederinae, as a result of convergent specialization, possibly due to a similar lifestyle and/or prey specialization. Unfortunately, beyond the association of at least some species of Antimerus and Pinophilini adults with foliage, these lifestyles and specializations remain unknown in both groups.