Modicarventus Kirman 1989

Genus Modicarventus Kirman, 1989

Fig. 20, 28, 38, 60–63, 81–82

Modicarventus Kirman, 1989a: 26.

Type species. Modicarventus wisei Kirman, 1989, by original designation.

Description (incrustation removed). Apterous. Body subovate to pear-shaped; length about 2.5–2.9 mm (male), 3.1–3.5 mm (female). Head. Eyes moderately large in relation to head, granulate. Postocular tubercles evanescent or at most forming short swellings. Rostrum arising from a closed atrium. Thorax. Pro-, meso-, and metanotum separated by distinct sutures. Pronotum. Double-ring collar distinctly set off from anterior margin, with lateral tubercles and posteriorly produced subtriangular plate. Disc bearing two moderately large subtriangular to subquadrate plates, one on each side of a narrow to moderately wide sulcus. Lateral portions with rows of coarse granules submarginally. Mesonotum. Disc bearing a large laterally winged plate (stouter than in Neocarventus, Tuataraptera) with a broadly rounded-subquadrate to subpentagonal backward projection reaching posterior margin of metanotum and two anterolateral projections divided into two anteriorly fused plates covering much of lateral portions; apex of backward projection flanked by two small transverse subtriangular to subovate metanotal plates. Posterior margin thickened, curved to the rear and produced on each side of backward projection (margin not thickened and curved to the rear in other genera). Metanotum. Disc largely covered by mesonotal projection. Posterolateral angles unproduced or faintly produced. Legs. Coxal lobes rugose. Trochanters and femora demarcated from each other. Femora granulate, about as long as tibiae. Protibiae with fine ventral spines and apical comb. Abdomen. Dmtg I–II separated from metanotum by a distinct suture; nearly separated medially by a longitudinal sulcus extending from anterior margin to posterior margin and bearing a small posterior callosity, separated from each other submarginally; lateral portions with a large subrectangular plate next to two subrectangular to subtriangular plates separated by a deep slit (as opposed to a pit in Clavaptera, Neocarventus, Tuataraptera). Tergal plate (dmtg III–VI) superficially unfused, with shallow sulci delimiting two moderately large subtriangular plates, a narrow, longitudinal plate, and apodemal markings. Dmtg III divided longitudinally by a median sulcus, each subtriangular half bearing an apodemal spot near anterior margin (dmtg III not divided by a sulcus in other genera). Dmtg IV–VI with a distinct, nearly diamond-shaped plate carrying scent gland openings (without granulate areas beside plate). Scent gland openings (or scars thereof) three in number, first large, displaced posteriorly on dmtg IV, second very small, third evanescent. Connexivum. Dorsal laterotergites (dltg) with a pair of distinct, rounded, smooth apodemal spots, posterior one larger. Dltg II–III fused, subtriangular, extending forward to posterolateral angles of metanotum; IV–VI subquadrate; VII subrectangular. Spiracles II–IV ventral (not visible from above), V–VII lateral (visible from above). Pattern of apodemal markings 2:1:1 (dorsal); 2:2:1 (ventral). Male genitalia. Pygophore trilobate (Fig. 20, posterodorsal view); dorsal lobes below carinate margin, nearly elliptical in shape, slightly convex, slightly produced backward, barely touching each other ventrally along their inner margin; ventral lobe narrowly bulbous medially, slightly produced; dorsal opening narrow; paramere heads partially visible as lamellate setose structures; posterior rim with a long, anteriorly directed, digitate projection on each side of median suture. Paratergites VIII (Fig. 28, outer lateral view) with an apically acuminate, sinuate-subtriangular head; spiracle distant from apex.

Remarks. The genus Modicarventus is unique among New Zealand genera in having the posterior margin of the mesonotum thickened, curved to the rear and produced on each side of the backward projection, and the dorsal mediotergite (dmtg) III of the tergal plate divided longitudinally by a median sulcus. Other chief morphological features distinguishing this genus from Clavaptera, Neocarventus, and Tuataraptera are highlighted in the generic description. The configuration of the male pygophore is akin to that of Tuataraptera. The shape of the paratergites VIII is somewhat reminiscent of Neocarventus. Modicarventus was previously known from a single species, M. wisei. A second species, M. kirmani, is described here. The genus is mostly confined to Northland, the northernmost region of the North Island.