Thortus simplex, Leschen & Chen & Harmer, 2024

Thortus simplex sp. nov.

( Fig. 17 View Fig )

Type material. HOLOTYPE: ♁ ( NZAC; card-mounted after dissection), labelled: ‘ Fell Pk. Richmond Ra. 4250′ 13.iii.69 J.C. Watt // Litter // NZ Arthropod Collection Private Bag 92170 Auckland New Zealand NZAC04235076 About NZAC ’.

Diagnosis. Thortus simplex sp. nov. is a unicolourous species with a unifacetted eye. It also lacks well-developed abdominal postcoxal lines which, instead, has a broad bead that extends a short distance onto the disc. It most closely resembles T. luscus sp. nov. but differs from it by having the pronotum widest in the anterior third and the elytra lacking parasutural striae.

Description. Length 1.37 mm. Colour of body unicolourous red-brown, with lighter antennal club, mouthparts and legs. Body surfaces glabrous, microsculpture absent. Dorsal setae silver, consisting of short scattered suberect, curved setae. Ventral surfaces with suberect slight curved setae; punctation ovate, prosternum mainly glabrous, mesoventrite foveolate, strongly impressed, disc of metaventrite with shallowly impressed punctures, punctation of abdominal ventrite 1 similar to metaventrite, punctation on ventrites 2 to 4 more denser, setae not longer at sides, but more erect than those on disc, punctation on ventrite 5 denser with a well-defined patch of posteriorly-directed setae. Head not lengthened with a relatively short gena with length subequal to length of antennomere 1; frons moderately constricted, narrowed to a width that is longer than half of the length of antennomere 1; supra-antennal ridge with well-developed rim, bead present; vertex delimited anteriorly by a transverse crenulate line, anterior surface distinctly punctured, posterior surface glabrous, small punctures present along the base; gular punctation irregular and ovate, diameters larger than those on sides of head. Eye consisting of a single facet. Antennomere 2 barrel-shaped, wider than long, antennomere 3 subconical, subequal and narrower than 2 and longer and nearly the same width as 4, proportions of antennomeres 4–8 same, antennomere 9 wider than 8 and narrower than 10 and 11, antennomere 10 transverse and about the same width as 11, antennomere 11 longer than 10, nearly as long as 9 and 10 combined. Pronotum transverse, pronotal length/width ratio ~0.88, widest at apical third; anterior margin convex; anterior angles obtuse, slightly projecting and acute; lateral edges weakly curved and convergent anteriorly, gradually converging posteriorly; pronotal disc with punctation somewhat uniform and foveolate, shallow, absent in central disc with a poorly defined median glabrous strip, separated by a distance of up to 1/2 to 1 times their diameter, though fused and larger in basal half; median impression absent; transversely depressed at basal 1/5; basomedial macropuncture present, triangulate; posterolateral angles obtuse, sharp, not slightly projecting posteriorly; posterior margin sinuate with a scutellar lobe. Prosternal process with well-developed lateral marginal beads, without longitudinal depression medially, process subparallel-sided and slightly converging posteriorly, not expanded posteriorly behind procoxae, apex curved, width subequal to width of procoxa and 0.5 times as long as length of prosternum; procoxal cavity without anterolateral notch. Scutellary shield heart-shaped and weakly transverse, 1.2 times as wide as long. Elytra about 1.44 times as long as combined widths, about 1.08 times as wide as width of pronotum, about 1.77 times as long as length of pronotum; setation uniform consisting of moderately long suberect, curved setae; humeral plica present; parasutural stria absent; punctation at base similar to that on pronotum, then smaller and sparser elsewhere on disc. Metaventrital process with anterior margin straight, marginal bead present at middle. Tarsi moderately slender, female unknown, 5-5- 4 in male, male with pro- and mesotarsomeres 1 and 2 with tenent setae; mesotarsomeres 1–3 of subequal lengths, mesotarsomere 5 subequal to tarsomeres 1–4 combined. First abdominal ventrite with broad rounded intercoxal process, postcoxal lines absent, but subcoxal bead broad. Aedeagus with relatively long parameres articulated to phallobase, paramere about 2.37 times as long as wide; apices subacute bearing single microsetae, without membranous projections; basipenis about 3.12 times as long as distipenis; distipenis about 1.75 as long as wide, lateral lobes not separated, basal plate absent (?); internal sac with a pair of slender sclerites.

Etymology. The specific epithet is the Latin adjective ‘ simplex ’, meaning ‘simple’, referring to its simple, single eye facet.

Distribution. South Island: MB ( Fig. 21 View Fig ).

Remarks. Thortus simplex sp. nov. is known by one specimen collected from litter in the Richmond Range. It was completely disarticulated and remounted on a card. The tegmen was lost after imaging. The genitalia were damaged during articulation and the apex of the internal sac was broken off.