Agnosthaetus stilbus ( Broun, 1910 )

Clarke, Dave J., 2011, A Revision of the New Zealand Endemic Rove Beetle Genus Agnosthaetus Bernhauer (Coleoptera: Staphylinidae), The Coleopterists Bulletin (mo 10) 2011, pp. 1-118 : 53-55

(22) Agnosthaetus stilbus ( Broun, 1910)

( Figs. 10 , 64 , 76 , 84 , 146 , 151 , 155 , Map 5 )

Dimerus stilbus Broun, 1910: 15 (Type locality: Waimarino); Broun 1921: 484.

Stenaesthetus stielus ; Scheerpeltz 1933: 1202. (error for stilbus ).

Agnosthaetus stilbus ; Bernhauer 1939: 214; Puthz 1980: 20; Herman 2001: 1875.

Type Material. Holotype (by monotypy). ♀, with eight labels: [ BMNH red bordered circular holotype label] “Holo-| type/ [Broun’ s handwriting] 3037./ New Zealand.| Broun Coll.| Brit. Mus.| 1922-482/ [Broun’ s handwriting] Waimarino.| Jany. 1909/ [Broun’ s handwriting] Dimerus stilbus ./ FMNH-INS 0000 048 416 / Dimerus | stilbus Broun | M.E. Bacchus det. 1977| HOLOTYPE / HOLOTYPE Dimerus stilbus Broun , ♀, teste D. Clarke 2011”, in BMNH. Specimen on card, mandibles spread. Broun’ s (1910) original description explicitly states only a single specimen was studied.

Additional Material Examined. 80 specimens (40♂ 40♀). NEW ZEALAND: North Island: Desert Rd., Summit , 1074 m, 26.xi.1985, 85/69, moss, R.C. Craw , 2♂, 1♀, FMNH-INS 38277–278, 279 (in NZAC); Manawatu, Ballance, 1912, A.E. Brookes Cn , 1♂, 1♀, FMNH-INS 38302, 42 813 (in NZAC); GB: Huiarau Range , 914 m, 17.i.1972, 72/23, litter, G.W. Ramsay , 1♂, 1♀, FMNH-INS 38257–258 (in NZAC); Urewera N.P., Lake Waikareiti , 38°47′, 176°10′, 19.iii.2000, 058, Dracophylum / Nothofagus litter, berlese, C. Carlton & A. Weir , 3♂, 2♀, LSAM 0154252–256 (in LSAM); Urewera N.P., Maungapohatu Rd. , 3.2 km E Taupeupe Saddle, 1110 m, ANMT 1148, 38°36.975′S, 177°2.753′E, mossy Nothofagus menziesii forest, 22.xi.2005, FMHD#2005-027, berl., leaf & log litter, A. Newton, M. Thayer, et al ., 3♂, 4♀ (in FMNH); Urewera N.P., Tawa Trk. Loop, nr. Lake Waikaremoana , 18.iii.0200, 050, leaf litter, berlese, C. Carlton & A. Weir , 1♂, LSAM 0154250 (in LSAM); HB: Balls Clearing Scenic Reserve , 39°16.14′S, 176°30.36′E, 13.iii.1980, 80/43, moss, M.F. Tocker , 1♀, FMNH-INS 38264 (in NZAC); 21.x.1984, 84/72, sifted litter and rotten wood, C.F. Butcher , 2♂, 3♀, FMNH-INS 38259–263 (in NZAC); Kaweka Ra., Top Birch , 23.ix.1991, ground litter, R. Whittle , 1♂, FMNH-INS 19802 (in MONZ); 23.iv.1990, ground litter, R. Whittle , 1♂, FMNH-INS 19803 (in MONZ); RI: Ruahine Ra., Armstrong Saddle , 1371 m, 39°47.07′S, 176°10.122′E [coord.=Armstrong Sdle], 23.ii.1970, 70/109, litter, G.W. Ramsay , 2♂, FMNH-INS 38265–266 (in NZAC); Ruahine Ra., Armstrong Saddle , 1250 m, 40°0′S, 176°6′E, tussock & alpine meadow, 8.ii.1980, ex Senecio bidwilli, C.F. Butcher , 1♀, FMNH-INS 38268 (in NZAC); Ruahine Ra., Armstrong Saddle , 39°47.1′S, 176°10.14′E, 10.ii.1980, 80/11 (1 or b), litter, C.F. Butcher , 1♂, 1♀, FMNH-INS 38270–271 (in NZAC); Ruahine Ra., Triplex , 39°47.7′S, 176°11.88′E [coord.=Triplex Hut], 10.ii.1980, 80/16, litter, C.F. Butcher , 1♀, FMNH-INS 38287 (in NZAC); TK: Egmont N.P., Dawson Falls , 950 m, 39°19.62′S, 174°6.48′E [coord.=Dawson Falls], native forest, 6.xii.1983, litter, P.M. Hammond , 1♀, FMNH-INS 38256 (in BMNH); TO: Erua , 39°14′S, 175°24′E, 1911 , 1♂, 1♀, FMNH-INS 42818–819 (in BMNH); Minginui S.F., 28.vii.1977, 77/88, litter, J.S. Dugdale , 1♂, FMNH-INS 38294 (in NZAC); Mt. Ruapehu , 1070 m, 39°16.998′S, 175°34.002′E, 28.i.1976, 76/1, wood mould, Nothofagus cliffortoides [sic], V.A. May , 1♀, FMNH-INS 38290 (in NZAC); Mt. Ruapehu , Whakapapanui Tk., 950 m, 39°11.562′S, 175°31.746′E, 7.xii.1994, 94/18, litter, J.S. Dugdale , 1♂, 1 sex unknown, FMNH-INS 38288–289 (in NZAC); National Park, Chateau , 1127 m (as 3700 ft), 16.ii.1958, berl., ex epiphytic moss, J.C. Watt , 1♂, AMNZ85006 (in AMNZ); National Park, Erua , 39°13.8′S, 175°24′E, 16.xii.1961, 61/15, litter, G. Kuschel , 3♂, 2♀ 2♂, 3♀, FMNH-INS 38272– 276 (in NZAC); Ohakune , 883 m, 39°24.78′S, 175°24.54′E, 26.i.1982, 82/17, litter, C.F. Butcher , 1♂, 1♀, FMNH-INS 38280, 285 (in NZAC); Ohakune Mt. Rd. Trk., 39°25.002′S, 175°25.002′E, 27.xi.1985, 85/73, litter, C.H.C. Lyal , 1♀, FMNH- INS 38284 (in NZAC); Ohakune Mt. Rd., Makotuku Flat , 39°18.9′S, 175°30.3′E, 27.xi.1985, 85/65, mixed swards, R.C. Craw , 1♂, FMNH-INS 38282 (in NZAC); Ohakune, Massey University, Alpine Hut , 944 m, 26.i.1982, 82/15, alpine mats, C.F. Butcher , 1♂, FMNH-INS 38281 (in NZAC); Tongariro N.P., Ohakune Mt. Rd. , 1400 m, 39°20′S, 175°31′E, 20.xi.2000, RL 605, leaf litter, R. Leschen , 2♀, FMNH-INS 38283, 286 (in NZAC); Tongariro N.P., Turoa Ski Village , 1463 m, 27.xi.1985, 85/75, sifted litter, C.H.C. Lyal , 1♂, FMNH-INS 38293 (in NZAC); Tongariro N.P., Whakapapa, Whakapapanui Strm. , 1400 m, 39°12′49″S, 175°32′57″E [coord.= Whakapapanui Stream], 28.xi.1986, S. Kiener , 4♂, 1♀, FMNH-INS 42808–812 (in Puthz); Waikato- Waipakihi Junction, Turangi (32 km S), 915 m, 39°0′S, 175°55.998′E, 19.ii.1979, 79/23, mosses, liverworth & litter, J.S. Dugdale , 1♂, 1♀, FMNH- INS 38291–292 (in NZAC); Waimarino , i.1909, T. Broun , 1♀, FMNH-INS 48416 (in FMNH); Waimarino, Main Trunk Line , 1♂, 2♀, FMNH-INS 42814–816 (in NZAC); Wairere Strm., below Taranaki Falls , 1582 m, 39°11.952′S, 175°33.54′E [coord.= Taranaki Falls], 25.xi.1965, 65/626, moss, J.I. Townsend , 1♀, FMNH-INS 48433 (in NZAC); WA: Tuhitarata Res., Lake Ferry , 41°17.7′S, 175°16.38′E [coord.=Tuhitarata Bush Scenic Reserve ], 19.xii.1983, forest litter, P.M. Hammond , 1♀, FMNH-INS 38313 (in BMNH); Tuhitarata, Lake Ferry (E side), 41°23.436′S, 175°8.304′E [coord.=Lake Ferry], 16.i.1984, litter, H.P. McColl , 1♀, FMNH-INS 38312 (in NZAC); WN: Ballance Bridge Res. [same as “Woodville Ferry Reserve ”?], 85 m, 28.viii.1983, 31/83, litter & humus, H.P. McColl , 1♂, FMNH-INS 38311 (in NZAC); Ballance Bridge Res., Bridge Cross Rd. [=“Woodville Ferry Reserve ”], 213 m, 40°24.06′S, 175°47.82′E, 23.viii.1983, 23/83, litter, H.P. McColl , 2♂, 7♂, FMNH-INS 38303–310 (in NZAC); Levin, Kimberley Reserve , 40°40.08′S, 175°18.84′E, 6.xi.1980, 80/103, litter, C.F. Butcher , 5♂, 2♀, FMNH-INS 38295–301 (in NZAC); Woodville, Ballance Res. , 60 m, 40°24.084′S, 175°47.808′E, 7.vii.1992, J.T. Nunn , 2♂, FMNH-INS 19771, 48 256 (in JTNC); WO: Kauri Flat, Waingaro (14 km SW), 37°45.66′S, 174°51.54′E, 26.xi.1983, leaf litter, P.M. Hammond, 1 sex unknown, FMNH- INS 38267 (in BMNH) .

Diagnosis. Agnosthaetus stilbus may be distinguished from all other known Agnosthaetus species by the combination of the lack of a medial spine on the anterior labral margin ( Fig. 146 ), smooth mentum (as in Fig. 67 ), lack of microsculpture on dorsal sides of head and thorax (except anterior part of the vertex), basolateral pronotal carina present ( Fig. 76 , bp), a single lateral elytral ridge ( Fig. 84 , ek), and distinctly developed metathoracic pleural ridge, but only short metathoracic pleural groove ( Fig. 84 , mp, gr; the latter may be almost absent in some individuals).

Redescription. Color: More or less uniformly reddish brown. Head ( Figs. 10 , 64 ): Frontal ridge present (cf. Fig. 12 , fr). Dorsum sparsely punctate; with punctures distributed anteriorly, laterally, and posteriorly on disc, middle part impunctate. Punctures shallow, rather indistinct; diameter variable, ranging from less than to slightly greater than diameter of eye facet; interpuncture distance approximately equal to or greater than puncture diameter, less posterolaterally. Dorsal microsculpture absent, or present only anterior to dorsal tentorial sulci; faintly reticulate. Dorsal tentorial sulcus (cf. Figs. 10–11 , dt) narrowly ovate; width subequal to or slightly greater than puncture diameter ( Fig. 10 , dt). Sublongitudinal ridge (cf. Fig. 10 , sr) distinct; not confused by smaller carinae or punctures ( Fig. 10 , sr); crest at antennal tubercle with or without distinct microsculpture. Area above and behind antenno-ocular carina ( Figs. 10–11 , arrow) usually without, or else only indistinct, subsidiary carinae. Antenno-ocular carina joining eye behind middle ( Fig. 10 , ao). Temple ( Fig. 11 , tm) short, less than 50% EYL. Subocular surface more or less evenly microsculptured ( Fig. 64 , zm). Labrum distinctly sexually dimorphic ( Fig. 146 ). Apical labral margin in males strongly emarginate medially, evenly dentate, with 10–19 teeth, with 2 broadly rounded, dorsally projecting, transversely oriented medial teeth, with or without up to 3 teeth between them. Apical labral margin in females slightly concave medially; all teeth subequal in length. Adoral labral surface in males with subapical transverse ridge ( Fig. 146 , arrow). Mandible sexually dimorphic; males with single, dorsally directed tooth, with distinct preapical spur (cf. Fig. 190 , arrow); females with single, mesially projecting tooth, without spur. Mentum smooth, unmodified ( Fig. 64 ). Prothorax: Pronotum without microsculpture. Medial pronotal sulci anteriorly separate from and terminating posterior to anterior punctures or continuous with anterior punctures (cf. Fig. 76 ). Distance between medial sulci subequal along entire length. Pronotal basolateral carina present, but only weakly developed ( Fig. 76 , bp). Anterior pronotal puncture (cf. Fig. 70 , ap) absent; medial puncture (cf. Fig. 70 , mu) absent, or present and variably distinct; basal puncture ( Fig. 70 , bu) absent. Medial pronotal seta subequidistant from medial and lateral sulci ( Fig. 76 ). Pronotal hypomeron ( Fig. 24 , hy) shiny, at most with only faintly visible microsculpture. Prosternum with faintly reticulate microsculpture. Pterothorax ( Fig. 84 ): Elytron ( Fig. 23 , e) without microsculpture, or with at most faint microsculpture; with 2 macrosetae, not set in punctures; laterally with single ridge ( Fig. 84 , ek). Mesothoracic epimeral region ( Fig. 24 , mer) shiny, without microsculpture. Metathoracic pleural region ( Fig. 24 , m) with faint reticulate microsculpture. Metathoracic pleural ridge present, fully developed; metathoracic pleural groove ( Fig. 24 , gr) incomplete posteriorly to nearly absent in some (reduced to small anterior depression). Abdomen: Abdominal vestiture short, somewhat appressed, dorsally more or less evenly projecting posteriorly. Abdominal sternite V of male with small diffuse patch of modified setae near apex. Aedeagus ( Fig. 151 ): “ Type B” (see description on p. 8). Median lobe with apical part delimited ventrally from basal part ( Fig. 151 , arrow). Apical part of median lobe with sides narrowed at middle, forming small subangulate apicolateral lobes, produced into broad point. Both apicolateral and apicomedial setae long ( Fig. 155 ). Shaft setae absent ( Fig. 155 , cf. Fig. 153 ). Paramere not exceeding apex of median lobe; slender in both dorsal and lateral view; in dorsal view with distinct inflection point in front of middle; with minute setae on mesal side of apex.

Distribution. ( Map 5 ). North Island: BP; HB; RI; TK; TO; WA; WN; WO. This species is one of two unusually widespread species in the North Island, and probably occurs throughout the lower two thirds of the North Island. This is highly unusual compared to the more restricted distributions of most other Agnosthaetus species.

Biology and Ecology. Habitat: Forest and alpine tussock. Specimens have been taken mainly from litter of various types and moss. Phenology: yearround. Elevation: 85–1,582 m.

Remarks. Although ultimately distinct in appearance, this rather robust species can be easily confused with many others from the lower North Island. But the lack of a basomedian mental tooth will separate it from A. imitator , A. aorangi , and A. orongo . The presence of the metathoracic pleural ridge will distinguish it from all species in the brouni species-group except A. aequalis and A. akatarawa . The lack of microsculpture from all dorsal surfaces except the anterior part of the vertex will distinguish it from A. lanceolatus . From A. akatarawa and A. minutus , it can be distinguished by the head punctation characters given in the respective descriptions, and from the former species additionally by the completely developed metathoracic pleural ridge.

Figures

Map 5. Geographic distribution of all georeferenced specimens of North Island species in the Agnosthaetus imitator species-group. Triangles = A. imitator; stars = A. aorangi; circles = A. lanceolatus; squares = A. stilbus; X = A. minutus.

Figs. 10–13. Head capsules of Agnosthaetus spp. 10) A. stilbus; 11) A. rodmani; 12) A. brouni; 13) A. chiasma. Scale bars = 100 mm.

Figs. 63–68. Heads of Agnosthaetus spp., ventral view. 63) A. brouni; 64) A. stilbus, oblique view; 65) A. chiasma;

Figs. 75–78. Pronota of Agnosthaetus spp. 75) A. vicinus; 76) A. stilbus; 77) A. nitidus; 78) A. brouni. Scale bar =

Figs. 83–88. Pterothoraces of Agnosthaetus spp., right lateral view. 83) A. lanceolatus; 84) A. stilbus; 85) A. chiasma;

Figs. 143–147. Male (left) and female (right) labra of species in the Agnosthaetus imitator species-group, dorsal (anterior margin) view. 143) A. imitator; 144) A. aorangi, female; 145) A. orongo; 146) A. stilbus; 147) A. lanceolatus. Scale bar = 100 mm.

Figs. 148–151. Aedeagi of species in the Agnosthaetus imitator species-group, dorsal (left) and right lateral (right) views. 148) A. imitator; 149) A. aorangi; 150) A. orongo; 151) A. stilbus. Scale bar = 100 mm.

Figs. 152–155. Apex of median lobe of species in the Agnosthaetus imitator species-group, ventral view.

Figs. 189–194. Mandibles of Agnosthaetus spp., dorsal view (189–193, left; 194, right). 189) A. newtoni; 190) A. falx; 191) A. stenomastax; 192) A. heteromastax (Rakeahua Valley); 193) A. heteromastax (Big South Cape Island); 194) A. heteromastax (Twilight Bay). Scale bar = 100 mm.

Figs. 69–74. Pronota of Agnosthaetus spp. 69) A. chiasma; 70) A. rodmani; 71) A. heteromastax; 72) A. stenomastax;

Figs. 23–24. Agnosthaetus cariniceps, thorax. 23) Dorsal view; 24) Left lateral view. Scale bars = 100 mm.