Irenimus stichus Brown

Brown, Samuel D. J., 2017, A revision of the New Zealand weevil genus Irenimus Pascoe, 1876 (Coleoptera: Curculionidae: Entiminae), Zootaxa 4263 (1), pp. 1-42 : 22-24

6. Irenimus stichus Brown , new species

Figures 5, 6 , 19, 20 , 36 , 73, 74, 75, 76, 77, 78 , 85

Diagnosis. Small to medium sized species; oval; dark grey to light grey, with mottling on the dorsum. Pronotum with lateral margins evenly curved. Scape without appressed scales. Elytra without interstriae 3 flat, elongate scales decumbent. Abdominal ventrites dominated by glossy, appressed scales and with few pappolepida. Males with ventrite 1 flat. Females with ventrites simple. Metatibiae more slender than in other species.

Description. Body length 3.12 mm to 4.80 mm (X = ̄ 3.88 mm, s = 0.61, n = 8). Integument black. Dorsum densely covered with appressed scales, colour variable, base colour ranging from light greyish brown and light greyish yellowish brown to deep reddish brown and dark brown; often with extensive mottling on the elytral disc, less on pronotal disc; frequently with a pale macula on vertex, an elongate pale macula on pronotal disc, and paler V-shaped band at top of elytral declivity, though not necessarily all these in combination. Femora with appressed scales dense, unicolorous, concolorous with elytra. Tarsi integument deep reddish brown. Rostrum. Length 0.66 mm to 0.98 mm (X = ̄ 0.83 mm, s = 0.12, n = 8), width 0.42 mm to 0.68 mm (X = ̄ 0.55 mm, s = 0.10, n = 8), length/ width ratio 1.36 to 1.79 (X = ̄ 1.52, s = 0.14, n = 8). Epifrons with appressed scales slightly overlapping; elongate scales setiform, erect, dark; medial and lateral carinae not evident. Dorsal carina slightly arched over antennal insertions. Lateral area ventrally of antennal insertions with thick setae, without appressed scales. Antennae. Scape relatively short, reaching around the middle of the eye when in repose; lacking appressed scales. Funicular segments moderately articulated; segments 1 and 2 clavate, subequal, around two times longer than segment 3; segments 3 to 6 subspherical, subequal; segment 7 oblately spheroid, longer than segment 6. Head. Eyes subcircular. Pronotum. Length 1.02 mm to 1.56 mm (X = ̄ 1.31 mm, s = 0.23, n = 4), width 1.02 mm to 1.52 mm (X = 1.30 mm, s = 0.22, n = 4), length/width ratio 0.98 to 1.03 (X = ̄ 1.01, s = 0.02, n = 4); widest in anterior 1/3, lateral margins evenly curved. Anterior margin entire, posterior margin evenly curved. Disc topography evenly convex; appressed scales tessellate; elongate scales setiform, erect, dark. Postocular lobes poorly developed. Anterior transverse groove weak beyond level with ventral margin of eye ( Figure 36 ). Posterior transverse groove weakly developed. Lateral posterior margin evenly curved ( Figure 36 ). Elytra. Length 1.88 mm to 2.80 mm (X = ̄ 2.34 mm, s = 0.39, n = 4), width 1.33 mm to 2.16 mm (X = ̄ 1.75 mm, s = 0.38, n = 4), length/width ratio 1.27 to 1.42 (X = ̄ 1.35, s = 0.08, n = 4). Anterior margin curved posteriad with humeral angles nearly porrect. Disc with appressed scales slightly overlapping; elongate scales setiform, semi-erect, dark on disc, pale laterally and posteriorly. Striae shallowly impressed; interstriae flat. Thoracic ventrites. Mesoventral process acutely rounded. Metaventrite densely covered with appressed scales. Abdomen. Ventrites with inner vestiture composed almost exclusively of appressed scales, ventrites 1 and 2 densely clothed, ventrites 3 and 4 sparsely clothed, ventrite 5 with dense scales anteriorly, bare posteriorly. Apex broadly rounded. Males with ventrite 1 slightly depressed, ventrite 5 flat. Female with ventrite 1 flat, ventrite 5 flat. Legs. Metatibiae with corbel present, broad, bare; ventral margin of apex slightly emarginate. Male genitalia. Figures 73, 74 . Penis with apex broadly rounded, almost sagittate; dorsal plate narrowed medially. Endophallus with longitudinal ostial sclerites; aggonoporial sclerite with long anterior and posterior lobes. Female genitalia. Figures 75–78 . Sternite 8 with blade elongate. Styli elongate. Vagina sclerotised. Bursa copulatrix moderate, sclerites absent. Spermatheca thick, ramus parallel with corpus. DNA Sequences: COI. KX191308 , KX191309 , KX191361 . 28S. KX191878 , KX191879 , KX191932 . ArgK. KX191591 , KX191592 , KX191643 . CAD. KX 191050 , KX 191051 , KX 191100 .

Type material examined. Holotype. Male ( NZAC). Specimen entire, mounted on card triangle. Labelled ‘ NZ: Tekapo, MK / 170.417969°S: 39413°E / Trap : C 1600 - 2 - 3 / Pawson, S.M. & McCarthy, J.K. / 27-Nov-07 to 17-Dec-07 ’ [printed, white card], ‘ NZ: Tekapo, MK / Tekapo Wilding Trial / Specimen number: 7 / 27-Nov-08 to 17-Dec-08 ’ [printed, white card], ‘ Irenimus taxonomy / and systematics / SDJ Brown / PhD Thesis 2012–2015 / IRE0398’ [printed, off-white card], ‘ HOLOTYPE / Irenimus stichus / Brown 2016’ [printed, red card].

Paratypes. A total of 125 specimens (35 males, 44 females, 46 of undetermined gender) designated as paratypes, bearing blue paratype label. Paratype specimens deposited in AMNZ, ANIC, BMNH, CMNZ, FRNZ, LUNZ, MONZ, NZAC, OMNZ, USNM.

MK: Burkes Pass Scenic Reserve [-44.092, 170.581, R], 19 Jan 2014, Brown SDJ , 690 m, Blower vac sample from road verge ( LUNZ: 2); Burkes Pass Scenic Reserve [-44.092, 170.583, R], 28 Dec 2012, Brown SDJ , 690 m, Blower vac sample from road verge ( LUNZ: 1); Burkes Pass Scenic Reserve [-44.0928, 170.5789, A], 15 Dec 2006, Johns PM , 670 m, Pitfall traps ( CMNZ: 1); Burkes Pass Scenic Reserve [-44.0928, 170.5789, A], 20 Nov 2006, Johns PM , 670 m, Pitfall traps ( CMNZ: 1); Curraghmore Station [-44.27592, 170.4435, R], 1 Dec 2006, Emberson RM, Syrett P , 610 m, Under sheep dung ( LUNZ: 1); Curraghmore Station [-44.28529, 170.4421, R], 1 Dec 2006, Emberson RM, Syrett P , 700 m, Under rock ( LUNZ: 1); Curraghmore Station [-44.30155, 170.4289, R], 1 Dec 2006, Emberson RM, Syrett P , 630 m, Under cow dung ( LUNZ: 1) ; Lake Tekapo [-44.0044, 170.4839, A], 20 Nov 1957, Evans PS ( NZAC: 1) ; Lake Tekapo [-44.0334, 170.418, R], 27 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( FRNZ: 11, LUNZ: 1, NZAC: 2, OMNZ: 1) ; Lake Tekapo [-44.0334, 170.418, R], 28 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( FRNZ: 3, USNM: 1) ; Lake Tekapo [-44.0334, 170.418, R], 28 Nov–17 Dec 2008, Pawson SM, McCarthy JK ( AMNZ: 2, FRNZ: 1) ; Lake Tekapo [-44.0394, 170.418, R], 27 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( ANIC: 2, BMNH: 4, FRNZ: 63, LUNZ: 1, MONZ: 2, NZAC: 2, OMNZ: 1, USNM: 1) ; Lake Tekapo [-44.0394, 170.418, R], 28 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( FRNZ: 4); Mackenzie Pass [-44.1934, 170.6115, A], 23 Nov 1960, On Pimelea sericeo-villosa ( NZAC: 8); Mt Cox [-43.981, 170.281, R], 27 Oct 2013, Brown SDJ , 830 m, Blower vac sample from grassland ( LUNZ: 1) ; Ohau River [- 44.2776, 169.9636, A], 13 Dec 1991, Johns PM, Sinclair L, Raoulia australis ( CMNZ: 1) ; Stony River [-44.36565, 170.3916, R], 30 Nov 2006, Emberson RM, Syrett P , 590 m, Under rock ( LUNZ: 2); Tekapo [-44.0334, 170.418, R], 28 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( LUNZ: 1); Tekapo [-44.0394, 170.418, R], 28 Nov–17 Dec 2007, Pawson SM, McCarthy JK ( LUNZ: 1).

Distribution. South Island:—/ MK /—( Figure 85 ).

MK: Burkes Pass; Curraghmore; Lake Benmore; Lake Pukaki; Lake Tekapo; Mackenzie Pass; Twizel.

Elevational range. Label data: 590 m to 830 m (X = ̄ 669 m, s = 68, n = 11). Georeferenced data: 518 m to 826 m (X = ̄ 723 m, s = 32, n = 126).

Etymology. Derived from the Greek stichos meaning ‘line’ or ‘row’, in reference to the visible metanepisternal suture.

Biology. Most specimens were collected in pitfall traps sited in grassland or in pine blocks surrounded by grassland. Other specimens were found under rocks or dung, collected through vacuum sampling in grassland, or were associated with Raoulia and Pimelea .

Figures

FIGURE 85. Distributions of Irenimus aniptus (circles), I. crinitus (squares), I. minimus (triangles) and I. stichus (stars).

FIGURES 1 – 8. Habitus photographs of Irenimus males. 1, 2: I. aniptus. 3, 4: I. crinitus. 5, 6: I. stichus, holotype. 7, 8: I. minimus. Scale bars = 1 mm.

FIGURES 15 – 22. Habitus photographs of Irenimus females. 15, 16: I. aniptus. 17, 18: I. crinitus. 19, 20: I. stichus. 21, 22: I. minimus. Scale bars = 1 mm.

FIGURES 35 – 36. Pronotum, left lateral view. 35, Irenimus crinitus; 36, Irenimus stichus. Abbreviations: atg—anterior transverse groove; ptg—posterior transverse groove; tooth—pronotal tooth.

FIGURES 73 – 78. Genitalia of Irenimus stichus. 73, penis, dorsal view; 74, aedeagus, lateral view; 75, tergite 8, dorsal view; 76, ovipositor, dorsal view; 77, ovipositor and spermatheca, lateral view; 78, sternite 8, ventral view. Scale bars = 0.5 mm; 7 3, 74 at same scale; 75 – 78 at same scale.