Zenascus nitidus ( Broun, 1893 ) Grzymala & Leschen, 2020

Grzymala, Traci L. & Leschen, Richard A. B., 2020, Sexual Dimorphism of New Zealand Puppet Beetles (Aderidae, Coleoptera, Tenebrionoidea): Systematic Revision, Description of Three New Genera, and Phylogeny for Zenascus, gen. n., Zootaxa 4889 (1), pp. 1-59 : 42-43

Zenascus nitidus ( Broun, 1893) , comb. n.

Figs 1A , 11D , 14D , 17A, 17B , 18D , 20D , 21D , 23D , 28A

Xylophilus nitidus Broun, 1893: 1163 ; Pic, 1894: 430; Pic, 1910: 13; Hudson, 1934: 204; Kuschel, 1990: 34, 66, Figs 72, 159; Maddison, 2010: 428.

Hylophilus nitidus ; Pic, 1902: 9; Pic, 1905: 215, 232; Pic, 1910: 13.

Diagnosis. This species is distinguished from congeners by the shining, black integument without secondary pubescence on the pronotum or elytra, the contrasting testaceous antennae and legs, and the unmodified antennae of males. Zenascus nitidus is most easily confused with Z. elenae and Z. antennalis , both of which also have a shining, black integument. Zenascus nitidus can be separated from Z. elenae by the differently shaped metatibia in both males and females ( Figs 17A, 17B, 17C, 17D ). Males of Z. nitidus also lack a medial impression on the fifth abdominal ventrite. Zenascus nitidus is distinguished from Z. antennalis by the absence of male antennal modifications and the overall testaceous antennomeres of females ( Figs 14E & 14F ).

Description. Length 1.53–1.80 mm. Head, clypeus, pronotum, elytra, venter, and metacoxae fuscous to piceous; scape, antennomere 11, labrum, mandibles, and metafemora brunneous to testaceous; pedicel and remaining antennomeres, remaining mouthparts, and remaining leg segments testaceous. Dorsal integument shining, vestiture uniseriate, one decumbent, thin, short seta arising anterad of each puncture, length about 2× puncture length, without additional setae between each pair of punctures. Ventral vestiture biseriate. Head, HW 0.42–0.47 mm, HL 0.20–0.23 mm, punctation consisting of numerous deep, elongate punctures, evenly spaced medially, clustered at basal and lateral edges on vertex, absent from base to just anterad of head constriction; impression between antennal ridge and vertex absent. Antennae witj distance between antennal insertions wide, approximately equal to diameter of five antennal insertions; length reaching past basal ¼ of elytra when extended backward; scape rounded, slightly longer than wide, subequal in width at base and apex; pedicel subglobular; antennomere 3 slightly reduced in width compared to pedicel, expanded apically; antennomere 4 longer than 3 and slightly greater in width; antennomeres 4– 8 subequal in length, each subsequent antennomere expanding slightly in width; antennomeres 9 and 10 decreasing in length, subequal in width; antennomere 11 elongate; antennomeres 3–11 covered in moderately dense, suberect pubescence; pedicel and antennomeres 3–11 with apical ring of elongate setae, antennomere 11 with additional medial ring of setae. Pronotum, PW 0.36–0.41 mm, PL 0.32–0.34 mm, subquadrate, slightly wider than long, width 1.13–1.24× length; pronotal width 0.52–0.60× elytral width, pronotal width 0.84–0.87× head width; sides slightly rounded; disc without two basal fovea, without transverse sulcus just anterad of center; punctation consisting of deep elongate punctures, approximately evenly spaced, separated by an average of three punctural lengths. Elytra longer than wide and longer than pronotal length, EW 0.62–0.78 mm, EL 1.21–1.32 mm; slightly impressed oblique subscutellar depression present; punctation consisting of elongate punctures, separated by an average of three punctural lengths. Proleg with tarsomeres 1 and 2 subequal in length, tarsomere 1 with ventral short, stout spine; tarsomere 3 with ventral adhesive setae. Midleg with tibia straight from base to apex. Hindleg with coxa without distinct, deep punctures along posterior margin; femur with distinctly thickened setae on postero-ventral face, overlying medial excavation confined to one-sixth femoral length, apico-ventral impression absent; tibia gradually expanded in width from base to apex, apex inner face triangular and apex densely pubescent. Abdomen with lateral length of ventrite 2 longer than length at midline; deep punctures confined to abdominal process. basal margin of ventrite 1, and basal margin and medially on ventrite 2; a central row of smaller present on ventrite 3; small, shallow micropunctures present on ventrites 4 and 5; ventrite 5 without medial impression. Phallobase broadly rounded anteriorly, delimited from apicale laterally and medially; apicale posteriorly narrowed, thin; accessory lobes absent; penis with anterior struts extremely elongate, extending past phallobase 2.5× length of struts within phallobase.

Females. Length 1.53–1.80 mm, HW 0.41–0.48 mm, HL 0.18–0.23 mm, PW 0.35–0.44 mm, PL 0.32–0.36 mm, EW 0.63–0.81 mm, EL 1.21–1.44 mm. Antennal scape rounded, slightly longer than wide; pedicel subglobular; antennomere 3 subequal in length to pedicel, ¾ width of pedicel; antennomere 4 subequal to 3 in width, slightly longer in length and width; antennomere 5–8 subequal in length, antennomere 9 slightly reduced in length, slightly greater in width, subequal to antennomere 10; antennomere 11 longer than 10, rounded. Protarsomere 1 without a ventral short, stout spine. Metatibia with long brush of thick setae originating basad to tibial apex.

Remarks. This is Broun species 2062 specimen based on a single female specimen from Wiatemata Harbour ( Broun 1893). The holotype was confirmed in the BMNH. A few specimens have been examined from Three Kings Island with a consistently darkened antennal scape, which is characteristic of Z. elenae . No additional morphological differences from North Island Z. nitidus were observed, but it is possible these specimens represent a diverging population of Z. nitidus .

Natural history. This is a relatively widespread and very common North Island species that is also found on the Three Kings Islands. This species has primarily been collected using Malaise traps and from light traps at night. Specimens have also been collected by sweeping and beating vegetation, specifically Melycitus ramiflorus , Phormium tenax , Carex sp., Geniostoma ? sp., Meryta sinclairii (Hook.) Seem , Dysoxylum spectabile (G. Forst) Hook. f., Corynocarpus laevigatus J.R. Forst. & G. Forst , Melicope ternata J.R. Forst. & G. Forst , Nestegis apetala (Vahl) L. A. S. Johnson , flowering Weinmannia silvicola Sol. ex A. Cunn. , flowers of Cordyline obtecta (Graham) Baker. Additional specimens have been collected from the bird nests of Zosterops lateralis (Latham) and Petroica macrocephala (Gmelin) .

Distribution. North Island : Northland (ND), Auckland (AK), Coromandel (CL), Waikato (WO), Bay of Plenty (BP), Taranaki (TK), Gisborne (GB) and Wellington (WN). Offshore Island : Three Kings Island (TH).

Type material examined. Holotype, female ( BMNH): “2062 // Northcote // New Zealand. / Broun Coll. / Brit. Mus. / 1922-482. // Xylophilus / nitidus [handwritten] // HOLOTYPE [female symbol] / “ Xylophilus ” / nitidus / Broun [handwritten] / det. J.C. Watt / 1985”.

Figures

FIGURES 1A–B. Zenascus species are most commonly found by daytime beating of broad-leaved plant species such as (A) Melycitus ramiflorus (with Z. nitidus resting on underside of leaf) and (B) Dysoxylum spectabile.

FIGURES 11A–E. Dorsal habitus images. (A) Zenascus coloratus (Broun), male; (B) Zenascus obscurus (Broun), male; (C) Zenascus aurum, sp. n., female; (D) Zenascus nitidus (Broun), male; (E) Zenascus elenae, sp. n., male. Scale bars = 1.0 mm.

FIGURES 14A–J. Antennal illustrations for Zenascus species, male on left, female on right.(A) Z. coloratus; (B) Z. obscurus; (C) Z. aurum, sp. n.; (D) Z. nitidus; (E) Z. elenae, sp. n.; (F) Z. antennalis; (G) Z. xenarthrus; (H) Z. roberti, sp. n.; (I) Z. luniger; (J) Z. incensum, sp. n. Scale bar = 0.1 mm.

FIGURES 17A–D. Scanning electron microscope images, Zenascus species, metatibia (A) Z. nitidus, male; (B) Z. nitidus, female; (C) Z. elenae, sp. n., male; (D) Z. elenae, sp. n., female. Scale bars = 30μm.

FIGURES 18A–E. Scanning electron microscope images, Zenascus species, elytron, dorsal view. (A) Z. coloratus; (B) Z. obscurus; (C) Z. aurum, sp. n.; (D) Z. nitidus; (E) Z. elenae, sp. n. Scale bars = 10μm.

FIGURES 20A–J. Scanning electron microscope images, ventral view of metafemora for Zenascus species. (A) Z. coloratus, male; (B) Z. obscurus, male; (C) Z. aurum, sp. n., male; (D) Z. nitidus, female; (E) Z. elenae, sp. n., male; (F) Z. antennalis, female; (G) Z. xenarthrus, male; (H) Z. roberti, sp. n., male; (I) Z. luniger, male; (J) Z. incensum, sp. n., male. Scale bars = 60μm.

FIGURES 21A–E. Abdominal ventrite illustrations for Zenascus species showing generalized punctation pattern. (A) Z. coloratus (Broun), male; (B) Z. obscurus (Broun), male; (C) Z. aurum, sp. n., male; (D) Z. nitidus (Broun), male; (E) Z. elenae, sp. n., male.

FIGURES 23A–J. Male genitalia illustrations for Zenascus species. (A) Z. coloratus; (B) Z. obscurus; (C) Z. aurum, sp. n.; (D) Z. nitidus; (E) Z. elenae, sp. n.; (F) Z. antennalis; (G) Z. xenarthrus; (H) Z. roberti, sp. n.; (I) Z. luniger; (J) Z. incensum, sp. n.

FIGURES 28A–C. Distribution maps. (A) Zenascus nitidus, (B) Zenascus obscurus, and (C) Zenascus roberti, sp. n.