Plinthisus (Nanoplinthisus) zuurbergi Sweet & Slater, 2004, n. sp.
Creators: name: Sweet, Merrill H.
name: Slater, James A.
Publisher: name: Zenodo
Year: 2004
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Rhyparochromidae
Plinthisus
Plinthisus zuurbergi

description: Plinthisus (Nanoplinthisus) zuurbergi n. sp.
(Fig. 16, 26, 36, 47, 64, 65, 77, 78, 94, 95, 108, 120)
Description. Brachypterous male. Pronotum, anterior 1/2 of head, legs and antennae light honey­yellow. Basal 1/2 of head dark red­brown. Scutellum, hemelytra, and abdomen a strongly contrasting dark chocolate brown, the abdomen almost black. Surface shining, appearing impunctate. Dorsum thickly clothed with elongate, semi­upright, posteriorly directed hairs, each in a micropuncture and as long as hairs on antennae. Posterior lobe and anterior collar of pronotum with slightly larger micropunctures. Relatively large punctures delimit posterior lobe of proepimeron. Long trichobothriumlike seta on eye, outside proximal surface of tibia, and lateral margin of pronotum 1/3 distance from humeral angle, pair on vertex 0.11 long, 0.13 apart and 0.06 from eye; shorter seta on tylus, eye, antenniferous tubercle and gena. [Abdominal sterna with 2 trichobothria on each side of midline of 3, 1 long and 1 short; 4 with 1 trichobothrium on each side of, and more remote, from midline; anterior trichobothrial hair of 6 and dorsal posterior hair of 6 and 7 very long (0.23); others shorter and inconspicuous (hard to distinguish from general investiture of hairs); posterior pair on 5 oblique, closer (0.015) together and nearer (0.025) to posterior margin of segment than to spiracle (0.045); posterior pairs on 6 and 7 similar, but progressively farther apart (0.03 and 0.04).]
Head non­declivent, acuminate, strongly convex across vertex. Tylus attaining distal 1/3 of 1st antennal segment. Tylus slightly convex, length head 0.14, width 0.07. Tylar sutures converging caudad. Juga gently convex, apices pointed. Lorum and gena nearly flat, polished. Antenniferous tubercles short, just visible from above; antennal insertion just below, and in front of eye. Eyes nearly in contact with anterolateral pronotal angles. Eye oval, small, of about 25 facets; eye length 0.08, height 0.22. Ocelli absent. Bucculae very low, height much less (0.02) than width of labial segment 1; very short, becoming ridges at level of apices of juga; ridges weak terminating caudad in a broad "U" at base of head. Venter of head more convex than vertex; telescoped ventral portion less enlarged than dorsal portion, length 0.11. Visible head length 0.24, width across eyes 0.34; interocular space 0.22, head height greatest (0.28) through telescoped area, height above eye 0.05, below eye 0.08, preocular length.15.
Pronotum broader across anterior 1/3 than across humeral angles, only slightly arcuate laterad, lateral margins sharply carinate; anterior margin strongly concave, anterolateral corners almost reaching eyes; posterior margin nearly straight. Collar and posterior lobe not evident externally [except by micropunctures and apodemes visible in cleared specimens]. Dorsum of anterior pronotal lobe moderately convex, height above lateral margin 0.04; pronotum medial length 0.43, [length posterior lobe 0.08 (cleared)]; width across anterior lobe, 0.53, width across humeri 0.50; [dorsal collar length 0.05 (cleared)]. Scutellum flat; length 0.20, width 0.34. Mesoscutum continuous with mesepisternum, not differentiated from scutellum, nor exposed laterad. Hemelytron pad­like with clavus and corium indistinguishably fused, without hinge, but base set off from scutellum; no membrane remnant. Posterior (distal) hemelytral margin truncate, straight, at right angles to body axis, and extending caudad to anterior portion of 4th abdominal tergum. Hemelytral margins strongly arcuate laterad, rounded, non­carinate, rolled to clasp pterothorax (Fig. 26). Hemelytra broader (0.32) than maximum pronotal width, length 0.42; commissure length 0.20; distance posterior margin of hemelytra to apex abdomen 0.52. [Metanotum pale, reduced, much exceeded caudad by scutellum. Metathoracic wing very reduced (Fig. 36), width 0.082, length 0.067. Stridulitrum sclerite oval, width 0.057, length 0.045, with 25 small (0.005 wide) teeth in 5–6 staggered rows. (In female, metanotum membranous; metathoracic wing absent.)] Posterior lobe of proepimeron compressed, very short, delimited by row of large punctures in sulcus. Propleural pore distinct, midway (0.10) between collar and pleural suture. Mesepisternum compressed; mesepimeron and metepisternum ecarinate below groove which receives hemelytron (Fig. 26). Metathoracic scent gland auricle (Fig. 26) short, directed caudad; apex slightly enlarged, bluntly rounded and with margins sharply elevated. Granulose scent area small, occupying less than ventral 1/2 of metepisternum. Metapleural flange not visibly delimited by groove from metepisternum; posterior margin of flange slightly concave (Fig. 26). Prosternum short, length 0.21; ventral collar length 0.08, set off by sulcus continuous with sulcus below lateral edge of pronotum; proxyphus depressed, sharply pointed. Mesosternum carinate, with transverse rugulae; mesoxyphus produced into narrow high tubercle, apex narrowly truncate. Metasternum flat, metaxyphus acute, sharply pointed. [Metacoxal bridges absent in both male and females. Mesendosternite short, apex splayed; mesendotergite short, incurved, apex cup­shaped, remote from mesendosternite.]
Abdomen oval; maximum width 0.64, length 0.67. Terga distinctly arched; connexivum tilted laterally up; caudal margin of tergum 7 rounded, extending a little caudad of connexivum. [Sternal sutures 3–4 and 4–5 incised, ridged; bent slightly cephalad at level of lateral trichobothria. (In female, intersegmental margin of sterna 4–5 straight.) Spiracles of segment 5 and 6 closer (0.05) to posterior than to anterior (0.10) margins. Terga 1 and 2 (Fig. 47) pale, mesally transparent, very lightly sclerotized; width 0.42. Plectrum small, with anterior margin darker, width 0.04, length 0.03,; extremely finely striate, striae anteriorly 0.4 µ apart, posteriorly <0.2 µ apart, near limit of light resolution. Tergum 3 little longer in middle, anterior margin straight, a distinct carina along posterior margin. Tergal sutures 4–5 and 5–6 not dovetailed, sutures curving caudad so that tergum 6 is shorter than 4, 5 or 7. Maximum width of terga 0.54; medial lengths: 1­0.03, 2­0.05, 3­0.06, 4­0.15, 5­ 0.18, 6­0.12, 7­0.17. Scent gland scar widths: 3–4: 0.18, 4–5: 0.13, 5–6: 0.14. Terga 4–7 inflexed and grooved laterad to receive mesal margin of connexivum. Epipleurites 3–6 very narrow (0.003) in width. Connexivum relatively narrow, hypopleurite widths: 2­0.02, 3­0.04, 4­0.04, 5­0.05, 6­0.04, 7­0.03; lengths: 2­0.04, 3­0.06, 4­0.06, 5­0.20, 6­0.23, 7­ 0.13; Hypopleurites 3 and 4 nearly fused together; hypopleurite junction 4–5 very oblique, with a distinct mesal notch into which fits pointed end of epipleurite 4; other junctions nearly transverse (Fig. 47). Tergum 7 internally impressed and sternum 7 with lateral shelves to receive segment 8 and genital capsule. Sternum 7 with no anterior apodemes visible. Genital capsule (Figs. 64 & 65) posteriorly excavate, width 0.24; posterior rim with distinct carina which meets clasper opening on midline; dorsal opening quadrate, large, nearly as wide as clasper opening; anterior bridge very narrow; parandria small, slender, bluntly pointed and twisted caudad. Epiproct (Fig. 64) membranous, represented by minute setae; paraprocts elongate, slender, C­shaped, nearly touching ventrad; single pair of anal sclerites, each bearing 4 setae. Clasper (Fig. 78) with shank and blade short and straight; blade strongly carinate on inner (frontal) surface. Phallus (Fig. 96 & 97) with gonoporal process of 4 basal coils with membranous sleeve, and 10–11 very slender distal coils; no helicoid process. Sperm reservoir enlarged basally; wings very small, triangular; holding sclerites small, shorter than reservoir. Phallotheca mostly desclerotized, with broad ventral sclerite and two slender dorsal sclerites. (In female, tergum 1 and 2 membranous; tergum 3 long, length 0.09, with anterior margin slightly convex, posterior margin transversely carinate. Epipleurite 3 present. Abdominal terga 6 and 7 fused, no suture visible. Tergum 8 flat; 2 submesal anterior sutures converging caudad to meet 1/3 distance before posterior margin. Tergum 9 short, strap­shaped, with long medial anterior apodeme; epipleurite 9 with small apodeme; hypopleurite 9 not cleft. Valvula length 0.31, apex with three long setae. Spermatheca (Fig. 108) with bulb asymmetrical, beret­shaped; sclerotized distal duct short, curved; unsclerotized basal duct very long, basally widened.)]
Profemur (Fig. 120) moderately incrassate, length 0.39, width 0.21; convex above, flattened beneath, inner distal surface sulcate to receive tibia; single small spine beneath halfway along femur. Protibia slightly bent, tiny tubercles on inner face, distal end clublike, enlarged; fitting in sulcus on femur, distal armed with a single inside (anterior) spur; protibial length 0.31, distal width 0.08. Procoxa with c­shaped tooth. Mesotibia and metatibia each with a row of 2 and a row of 3 spurs; metatibia length 0.38; medial width 0.04; lengths of metatarsomeres: I 0.11, II 0.05, III 0.06. Labium extending between mesocoxae; 1st segment not attaining base of head; labial segment lengths: I 0.18, II 0.20, III 0.14, IV 0.13. Antennae stout, segments fusiform, moderately thick, 0.07; antennal segment lengths: I 0.14, II 0.19, III 0.15, IV 0.22. Total body length 1.47.
Materials examined. HOLOTYPE: SOUTH AFRICA: Cape Province: 1 mi. S. Zuurberg Pass Summit, 1,800', 15.II.1968 (M. H. Sweet, T. Schuh no. 196). In National Collection of Insects, Pretoria, South Africa.
PARATYPES: (all brachypterous) 8 m 15 f (2 m 2 f dissected). Same data as holotype. In J. A. Slater and M. H. Sweet collections.
Etymology. This distinctive species, unrelated to any other Plinthisus species­group, is known only the Zuurberg, an isolated mountain in the Eastern Cape, thus the genitive ending meaning, Plinthisus of the Zuurberg.
Discussion. P. zuurbergi is superficially very similar to P. drakensbergensis, agreeing in general size, habitus, pronotal coloration and elongate hairs on the dorsal surface. However, P. zuurbergi is readily distinguishable by the metathoracic scent gland auricle being curved caudad (Fig. 26), not recurved cephalad (Fig. 27); by the profemur having a single spine (Fig. 119), not mutic (Fig. 121); and by the dark color of the scutellum, hemelytra and abdomen which contrasts strikingly with the yellow, pronotum, whereas in P. drakensbergensis the whole dorsum is light yellowish. In actuality, as indicated in the key, P. zuurbergi forms a separate species­group. It has no other close relatives and appears to have a restricted range.
We place the Zuurbergi species­group in Wagner's subgenus Nanoplinthisus because the hemelytron lacks a marginal membrane, is transversely truncate at the level of tergum 4, and the clasper is straight with a carinate blade.
DRAKENSBERGENSIS SPECIES­GROUP
description: Published as part of Sweet, Merrill H. & Slater, James A., 2004, An analysis of species­groups of the genus Plinthisus Stephens (Hemiptera: Rhyparochromidae) in the Ethiopian Region with the description of eight new species, pp. 1-56 in Zootaxa 533 on pages 33-36, DOI: 10.5281/zenodo.157231