Thortus sulcatus, Leschen & Chen & Harmer, 2024

Thortus sulcatus sp. nov.

( Fig. 18 View Fig )

Type material. HOLOTYPE: ♁ ( NZAC), labelled: ‘ New Zealand SL Slopedown Ra, N of Slopedown Hill 28/1 – 5/2/08 // Pit trap c 580m Steve Rate // Manuka /inaka shrubland E2208228 N5423327 // NZ Arthropod Collection Private Bag 92170 Auckland New Zealand NZAC04235121 About NZAC .’ PARATYPES (5; NZAC). SOUTH ISLAND: MC: 1, Port Hills,Ahuriri Scientific Reserve, 7 Apr 2007, washed soil sample broadleaf forest, J. Nunn,

[43°39.933′S, 172°36.643′E], NZAC 04235236. SL: 1, Owaka, Tautuku Reserve, 19 Jan 1978, S.B. Peck, J. Peck, [46°35.1′S 169°25.133′E], S. & J. Peck Collection, NZAC 04272532; 1, Purakaunui, near Owaka, 31 Dec 1995, J. Nunn Collection, 46°31.181′S, 169°31.667′E, NZAC 04235103; 2, Waionepu Creek, near Tokanui, 13 Feb 1968, litter, J.I. Townsend, 46°36.376′S, 168°58.66′E, NZAC 04235127, NZAC 04235134.

Diagnosis. Thortus sulcatus sp. nov. is most similar to T. amoenus and T. occidens sp. nov., which have complete parasutural striae and long genae, but is easily recognized from these and all other species by having a median pronotal impression.

Description. Length 1.60–1.70 mm. Colour of body dark reddish-brown, mouthparts, legs, and antennal club lighter. Body surfaces semiglabrous, microsculpture absent. Dorsal setae silvery-gold, sparse, dual, consisting of very long decumbent and scattered suberect curved and straight setae. Ventral surfaces with shorter decumbent mostly straight setae; punctation ovate, well-impressed, and uniform, mesoventrite foveolate, central disc of metaventrite with punctures of different sizes, mostly about the same or a little larger than those of prosternum, punctation of abdominal ventrites 1 to 4 generally smaller than those on metaventrite, with those on ventrite 1 generally larger than those on ventrites 2–5, punctation on ventrite 5 denser with a well-defined patch of posteriorly-directed setae. Head lengthened with relatively long gena, about 1.5 times as long as length of antennomere 1; frons constricted, narrowed to width to about half the length of 2/3 rd the length of antennomere 1; supra-antennal ridge with well-developed rim, relatively broad bead present; vertex not delimited anteriorly by a weak transverse crenulate line, surface rugulose with deep irregular punctures (one specimen weakly punctate in the middle); gular punctation deep and ovate, diameters about equal to those on sides of head. Eye consisting of about 20 facets.Antennomere 2 cylindrical, about as wide as long, antennomere 3 subconical, longer and as wide as 2 and longer and slightly wider than 4, proportions of antennomeres 4–8 same, antennomere 9 wider than 8 and narrower than 10 and 11, antennomere 10 transverse and narrower than 11, antennomere 11 longer than 10, shorter than 9 and 10 combined. Pronotum subquadrate, pronotal length/width ratio ~0.96, widest at middle; anterior margin slightly curved; anterior angles obtuse; lateral edges somewhat evenly rounded and gradually converging anteriorly and posteriorly; pronotal disc with punctures regular and uniform, separated by a distance of 0.5–1.0 times their diameter; median impression present, glabrous within; not or weakly transversely depressed at base; basomedial macropuncture absent; posterolateral angles obtuse and rounded, not projecting posteriorly; posterior margin sinuate without scutellar lobe. Prosternal process with well-developed lateral marginal beads, with longitudinal depression medially, process weakly widened posteriorly behind procoxae, apex subacute, width subequal to width of procoxa and 0.47 times narrower than length of prosternum; procoxal cavity with anterolateral notch. Scutellary shield ovoid, 1.45 times wider than long. Elytra about 1.20 times as long as combined widths, about 1.17 times as wide as pronotum at greatest width, about 1.46 times as long as length of pronotum; setation singular, consisting of very long decumbent setae; humeral plica present; parasutural stria present and complete, interspace setose; punctation similar to pronotum near base, but separated by a distance of up to 1–3 times their diameter and less impressed towards apex. Metaventrital process with anterior margin straight, marginal bead completely absent. Tarsi moderately slender, 5-5- 5 in female, 5-5- 4 in male, male protarsomeres 1–2 with tenent setae; mesotarsomeres 1–3 of subequal lengths, mesotarsomere 5 slightly longer than tarsomeres 1–4 combined. First abdominal ventrite with postcoxal lines convex, extending to mid-length of sclerite; intercoxal process rounded at apex. Aedeagus with relatively long parameres articulated to phallobase, paramere about 3 times as long as wide; apices subacute, asetose (?), and lacking membranous extensions; basipenis about 4.04 times as long as distipenis; distipenis about 1.67 times as long as wide, lateral lobes not separated, basal plate absent; internal sac with a pair of short slender endophallites that are anteriorly widened and spatulate.

Etymology. The specific epithet is the Latin adjective ‘ sulcatus ’, meaning ‘furrowed’, in reference to the impression on the pronotum.

Distribution. South Island: MC, SL ( Fig. 21 View Fig ).

Remarks. Thortus sulcatus sp. nov. is known from six specimens collected by leaf litter sifting. It is known by only four specimens from Southland, with one specimen collected from the Port Hills. Crowson labelled specimens of this species as ‘ Pithortus ’ n. sp.