Zenascus xenarthrus ( Broun, 1910 ) 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 : 51-53

Zenascus xenarthrus ( Broun, 1910) , comb. n.

Figs 12B , 14G , 19B , 20G , 22B , 23G , 24C , 27A

Xylophilus xenarthrus Broun, 1910: 54 ; Champion, 1916: 48; Hudson, 1923: 386; Hudson, 1934: 204; Maddison, 2010: 428.

Diagnosis. This species is separated from congeners by the biseriate pubescence of the elytra, the greatly modified antennae of males, the brunneous to piceus dorsal coloration, and the strongly impressed basal pronotal fovea. Ze-nascus xenarthrus is most easily confused, especially for females, with Z. antennalis . Males are easily separated by the differences of their modified antennomeres ( Figs 14F & 14G ). Both males and females can be distinguished by the elytral pubescence, which is uniseriate for Z. antennalis and is biseriate for Z. xenarthrus .

Description. Length 1.46–1.84 mm. Head, pronotum, elytra, and venter brunneous to castaneous; antennae, mouthparts, and legs testaceous to brunneous. Dorsal integument matte, vestiture biseriate, with one decumbent, thin, long seta arising anterad of each primary puncture, length about 2× puncture length, with additional 2–3 decumbent, thin, shorter setae between each pair of punctures, length about 2/3× primary seta. Ventral vestiture similar to dosum, biseriate. Head, HW 0.48–0.54 mm, HL 0.21–0.30 mm, punctation cosnsiting of few, deep punctures, unevenly spaced on vertex, absent from base to posterior edge of eyes; a moderate impression present between antennal ridge and vertex. Anteannae with distance between antennal insertions narrow, approximately equal to diameter of 1.5 antennal insertions; length reaching past basal ¼ of elytra when extended backward; scape broad and flattened, approximately 3× length of pedicel; pedicel transverse, width greater than length; antennomere 3 minute, shorter than pedicel and shorter than antennomere 4, only visible with high magnification; antennomere 4 dorso-ventrally flattened, elongate, length 3.5× width, longer than antennomere 5; antennomeres 5 and 6 subequal in width, antennomere 5 slightly longer than antennomere 6, both inwardly curved; antennomeres 7–9 dorso-ventrally flattened, apex approximately 2× width of base, inner apices expanded; antennomere 10 width subequal to length; anennomere 11 length 2× antennomere 10; antennomeres 3–11 covered in moderately dense, suberect pubescence, antennomeres 10–11 with additional pilosity. Pronotum, PW 0.36–0.44 mm, PL 0.33–0.41 mm, subquadrate, width subequal to slightly greater than length, width 1.06–1.09× length; pronotal width 0.54–0.60× elytral width, pronotal width 0.75–0.81× head width; slightly sinuate; disc with two strongly impressed basal fovea, a slight transverse sulcus present just anterad of center; punctation consisting of deep, elongate punctures, unevenly spaced, separated by an average of 1.5 punctural lengths. Elytra 1.81–1.91× longer than wide and 3.42–3.53× longer than pronotal length, EW 0.60–0.75 mm, EL 1.13–1.43 mm; slightly impressed, oblique subscutellar depression present; punctation consisting of elongate punctures, separated by an average of 1.5 punctural lenths. Proleg with tarsomere 1 approximately 2–3× longer than tarsomere 1, without a ventral short, stout spine; tarsomere 3 with ventral adhesive setae. Midleg with tibia straight from base to apex. Hindleg with numerous deep, elongate punctures along posterior margin of coxa; femur with distinctly thickened setae on postero-ventral face, overlying slight excavation extending entire length of femur, apico-ventral impression absent; tibia gradually expanded in width from base to apex, apex inner face triangular and densely pubescent. Abdomen with lateral length of ventrite 2 greater than its medial length; deep punctures confined to abdominal process and basal margin of ventrite 1, medially on ventrite 2 and several scattered on ventrite 3; small, shallow micropunctures present on ventrites 4 and 5; ventrite 5 without medial impression. Phallobase broadly rounded anteriorly, laterally delimited from apicale, without distinct sclerotization; apicale posteriorly narrowed, tip expanded, with apex rounded; accessory lobes present, subequal thickness at base and apex; with four setae confined to accessory lobe apex; penis with anterior struts elongate, but not extending past phallobase.

Females. Length 1.70 mm, HW 0.51 mm, HL 0.26 mm, PW 0.38 mm, PL 0.35 mm, EW 0.75 mm, EL 1.35 mm. Antennae with distance between antennal insertions narrow, approximately equal to diameter of two antennal insertions; scape longer than wide, slightly flattened; pedicel subglobular; antennomere 3 longer and about ½ width of pedicel, antennomere 3–7 subequal in width and length; antennomeres 8–11 each shorter than antennomere 7, each subsequent antennomere becoming slightly wider, forming a weak club.

Remarks. Because of the modified antennae, Broun (1910) suggested that this species be placed in a separate genus but refrained due to the specimen being damaged. This is Broun species 3117, which was based on a single male damaged specimen from Raurimu collected in 1909 ( Broun 1910). The holotype was confirmed in the BMNH.

Natural history. This is a relatively uncommon species that is widespread in the North Island. This species has been primarily collected using Malaise traps but has also been acquired through beating vegetation at night, on the underside of a log on the forest floor, and in a pitfall trap.

Distribution. North Island : Northland (ND), Auckland (AK), Rangitikei (RI), Wanganui (WI), Wellington (WN), and Wairarapa (WA).

Type material examined. Holotype, male ( BMNH): “3117 // New Zealand. / Broun Coll. / Brit. Mus. / 1922- 482. // Raurimu / Jany. 1909. [handwritten] // Xylophilus / xenarthrus [handwritten] // HOLOTYPE [male symbol] / “ Xylophilus ” / xenarthrus / Broun [handwritten] / det. J.C. Watt / 1985”.

Figures

FIGURES 12A–E. Dorsal habitus images. (A) Zenascus antennalis (Broun), male; (B) Zenascus xenarthrus (Broun), male; (C) Zenascus roberti sp. n., male; (D) Zenascus luniger (Champion), male; (E) Zenascus incensum 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 19A–E. Scanning electron microscope images, Zenascus species, elytron, dorsal view. (A) Z. antennalis; (B) Z. xenarthrus; (C) Z. roberti, sp. n.; (D) Z. luniger; (E) Z. incensum, 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 22A–E. Abdominal ventrite illustrations for Zenascus species showing generalized punctation pattern. (A) Z. antennalis, male; (B) Z. xenarthrus, male; (C) Z. roberti, sp. n., male; (D) Z. luniger, male; (E) Z. incensum, 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 24A–F. Scanning electron micrographs of gland pores on metafemur of Zenascus spp. (A) Z. aurum, sp. n.; (B) Z. antennalis; (C) Z. xenarthrus; (D) Z. roberti, sp. n.; (E) Z. luniger; (F) Z. incensum, sp. n. Scale bars = 2μm.

FIGURES 27A–D. Distribution maps. (A) Zenascus aurum, sp. n., Zenascus incensum, sp. n., and Zenascus xenarthrus, (B) Zenascus coloratus, (C) Zenascus elenae, sp. n. and (D) Zenascus luniger.