Triplatyx ribesi, Kment, 2011

Triplatyx ribesi sp. nov.

( Figs. 1, 2, 3 g-i)

Type locality:

Madagascar (west coast), Toliara [= Tuléar] province, Ianantsony [= St. Augustin], 23º33'10'' S 43º45'41'' E. Type material examined:

HOLOTYPE: ♂, « MADAGASCAR / Tulear Pr. / St. Augustin s.l. / 29.III..1968 / K.M.G. & P.D. [p, white label] // Brit. Mus. / 1968-321 [p, white label] // ♂ [p, white label] // HOLOTYPUS / TRIPLATYX / RIBESI / sp. nov. / det. P. KMENT 2010 [p, red label]» ( BMNH) . The holotype ( Figs. 1, 2a) is glued on tip of pentagonal white card; there is a pin hole in right side of its scutellum, the left hemelytron is slightly deflected, and right antennomeres 4 and 5 and left apical fore tarsomere are missing. The dissected pygophore is glued to the same piece of card, the phallus and one paramere are mounted in DMHF on a translucent plastic card attached to the same pin; second paramere remains in pygophore.

PARATYPES: 1 ♂ 1 ♀, « MADAGASCAR / Tulear Pr. / St. Augustin s.l. /29.III..1968/ K.M.G. & P.D. [p, white label] // Brit. Mus. / 1968-321 [p, white label] // ♂ [p, white label] // PARATYPUS / TRIPLATYX / RIBESI / sp. nov. / det. P. KMENT 2010 [p, red label]» (1 ♂ NMPC, 1 ♀ BMNH) .

Description:

Colouration. Body dorsally pale brown, pronotum and scutellum without pale, callose longitudinal midline. Antennae pale brown, antennomere 1 somewhat darker basally, apical half of antennomere 4 and apical two-thirds to three-quarters of antennomere 5 dark brown to black. Eyes dark brown with reddish tinge. Narrow pale median spot at lateral margin of laterotergites missing or only slightly contrasting. Venter of body dark brown; abdomen medially with large yellowish callosities. Rostrum brownish, apically dark brown. Legs pale brown with irregular brown spots; claws in apical halves black. Abdominal spiracles dark brown. Membrane colourless, translucent, with brown veins. S c u l p t u r e. Body dorsally densely to very densely punctate. Interspaces among punctures narrower than or as wide as their diameters; if wider, then forming irregular, pale, convex callosities. Punctures brown to dark brown; dark punctures here and there forming short, ca. horizontal chains. Callosities on dorsum only slightly developed, sparse, scattered, small and irregular. Basal angles of scutellum with small, raised, globular, ivory to beige callose grain. Venter of body very densely punctate, punctures on thorax distinctly larger and sparser than those on head and abdomen, abdomen medially with much sparser punctation than on sides; base of head, thorax and abdomen with many small irregular beige callosities, less prominent on abdomen. Legs without distinct punctures.

Structure. Head strongly declivous ( Fig. 2a), nearly trapezoid in outline ( Fig. 1). Lateral margins in front of eyes with triangular anteocular spine, more anteriorly slightly but distinctly incised; paraclypei foliaceous, flattened, long and wide, widening laterad in front of lateral incision and rounded mesad anteriorly, more or less regularly arcuate; anterior margin of head nearly straight; paraclypei meeting in front of clypeus, forming only small incision; paraclypei flat, with anterior margin both dorsally and ventrally lacking setae. Clypeus and frons slightly convex to nearly flat. Antennomeres ordered from shortest to longest as 3 <1 <2 <4 <5. Bucculae low, slightly narrowing both anteriad and posteriad, rounded on both apices, with lower margin slightly insinuated to nearly straight medially. Apex of rostrum reaching between mesocoxae or towards anterior margins of metacoxae.

Pronotum ( Figs. 1, 2a). Anterolateral angles truncated, wide, weakly protruding anteriorly, laterally with distinct spine. Anterolateral margins nearly merging with humeral angles and very variable in shape: slightly concave, carinate, bearing one minute to large triangular spine medially or one large and one minute spine. Humeral angles very wide, distinctly produced anteriad, declivous, widely rounded, anteriorly and laterally bearing 4-7 well developed to hardly distinct triangular or lobe-like projections; the most anterior projection usually best developed, the most posterior one slightly protruding of arcuate outline. Margins of pronotum behind humeral angles regularly rounded, narrowing towards scutellum; posterior margin straight to slightly concave. Pronotal disc anteriorly and medially slightly convex, strongly declivous towards head, without distinct median elevation; dorsal surface of humeral angles continuous with rest of pronotum, only slightly concave basally; posterior part of pronotum distinctly convex sublaterally, slightly convex medially, confluent with anterior surface of scutellum.

Scutellum. Basal angles shallowly depressed; disc slightly and regularly elevated, not forming a hump, convex in anterior two-thirds of scutellum and continous with surface of pronotum; lateral surfaces flattened in midlength of scutellum; posterior surface towards scutellar apex nearly flat.

Hemelytra ( Fig. 1). Clavus with 3-4 irregular rows of punctures in widest place; apex of membrane almost reaching to slightly surpassing apex of abdomen; veins of membrane reticulate.

Thorax ventrally flattened; sternum between coxae furrowed. Ostiole situated on small tubercle, round, directed obliquely ventrolaterad and accompanied with small spout less than twice longer than ostiole width; metapleuron around ostiole not depressed. Evaporatorium small, developed both on meso- and metapleuron; on mesopleuron forming only narrow strip along posterior margin and widened in its depressed posterolateral angle; evaporatorium on metapleuron narrowly surrounding tubercle bearing ostiole and projecting as narrow strip mesad between meso- and metacoxae, and laterad on anterior margin of metapleuron along thoracic spiracle and further laterad; depressed evaporatory channel well developed; gyrification of evaporatorium not apparent.

Legs. Protibiae hardly widening towards apex, their outer surface distinctly flattened, lateral margins carinate.

Abdomen slightly narrower (♂♂) to slightly wider (♀) than pronotum across humeral angles; sternite III not depressed anteromedially. Laterotergites fully exposed dorsally, mediotergites completely covered with hemelytra; laterotergite III laterally distinctly bisinuate, with median projection and posterior angle more or less protruding; laterotergites IV-VI laterally slightly bisinuate to nearly straight, laterotergites VII-VIII laterally nearly straight; dorsal surface of laterotergites nearly flat, sometimes with shallow depressions medially.

M a l e g e n i t a l i a. Pygophore ( Figs. 2b, 3 g-i) relatively small (pygophore width 0.75-0.80 mm, ratio pygophore width to body length 0.15-0.16, n = 2); ventral wall slightly gibbose basally, nearly flat posteromedially ( Fig. 3i); ventral rim medially not developed, laterally indicated by shallow ridges on posterolateral angles; ventral wall continually merging into ventral rim infolding, only ventral wall depressed subapically at base of posterolateral angles which are protruding ventrally ( Figs. 3 h-i); ventral rim infolding parallel with ventral wall, slightly concave medially, only its lateral projections slightly bent dorsally, obtusangulate ( Figs. 2b, 3g); posterolateral angles of pygophore more widely rounded laterally, lateral rim of posterolateral angles narrow; lateral rim infolding dorsally with sharply pointed tooth-shaped projection on each side ( Figs. 2b, 3g); paramere sockets distinct; apices of parameres visible, directed obliquely dorsolaterally. Paramere simple, laterally flattened, apical portion slightly longer than basal portion, medially curved, crescent-shaped, apically narrowly rounded ( Fig. 2c); apex of paramere in dorsal view slightly widened and flattened. Phallotheca of aedeagus like in T. dubius, slightly oval, sclerotized apical processes of median penal plates narrow, well developed ( Fig. 2d).

Female genitalia. Gonocoxites 8 with posterior margin slightly concave and sutural margin slightly convex, both gonocoxites 8 almost in contact medially; gonapophyses 9 visible; posterior margin of laterotergites 9 narrowly rounded.

Measur ements (♂ holotype, ♂ paratype / ♀ paratype) (mm). Body length (from apex of paraclypei to apex of membrane): 4.8, 5.4 / 5.5; head length (from apex of paraclypei to the anterior pronotal margin): 1.35, 1.30 / 1.40; head width (maximum width across eyes): 1.65, 1.70 / 1.70; vertex width (between eyes): 1.35, 1.35 / 1.35; length of antennomeres: 1: 0.30-0.33, 0.30 / 0.35; 2: 0.30-0.35, 0.35 / 0.33-0.35; 3: 0.28, 0.30 / 0.35; 4: 0.35, 0.40 / 0.40-0.43; 5: 0.50, 0.50 / 0.55-0.58; pronotum length (medially in most exposed view): 1.30, 1.30 / 1.45; pronotum width (maximum width between apices of humeral angles): 3.8, 4.0 / 4.3; scutellum length (medially from base to apex): 1.95, 2.10 / 2.40; scutellum width (maximum width at base): 2.25, 2.40 / 2.50; abdomen width (maximum width across laterotertgites III or IV): 3.75, 3.80 / 4.55; pygophore width (in posterodorsal view): 0.75, 0.80.

Variation:

The examined males completely lack pale median callose line on pronotum and scutellum, while in the female this is present though very short and limited to ca. posterior quarter of pronotum. All three specimens also differ in number and shape of projections on anterolateral and lateral margins of pronotum.

Differential diagnosis:

Triplatyx ribesi sp. nov. belongs to T. quadraticeps species-group including also T. quadraticeps, T. dubius and T. kerzhneri, all the species being habitually very similar. The T. quadraticeps species-group is defined by the following characters: head trapezoid in outline; humeral angles of pronotum more or less rounded; thorax ventrally flattened; peritreme in form of very small spout, directed obliquely ventrolaterad; metapleuron around ostiole hardly depressed; evaporatorium small with well developed depressed evaporatory channel; protibiae not widening towards apex; legs without distinct punctures; outer margin of laterotergites only slightly bisinuate to nearly straight. The four included species can be distinguished with certainty only according to genitalic characters, especially the structure of the pygophore (see the key below).

According to present knowledge, Triplatyx ribesi sp. nov. differs from T. kerzhneri, T. quadraticeps and some specimens of T. dubius by lack of the scutellar hump. However, this character is also missing in some specimens of the highly variable and sympatric T. dubius, from which the new species cannot be reliably separated otherwise than according to male genitalia. In the structure of pygophore, T. ribesi sp. nov. is most similar to T. quadraticeps, sharing the posterolateral angles of pygophore protruding ventrally and paired tooth-shaped projection dorsally on lateral rim infolding. T. ribesi sp. nov. differs from all the Triplatyx species by the following combination of characters: Pygophore with ventral wall slightly gibbose basally and flat posteromedially, only ventral wall shallowly depressed subapically at base of posterolateral angles ( Figs. 3 h-i); ventral rim infolding parallel with ventral wall, only its lateral projections bent dorsally, less prominent and obtusangulate ( Fig. 3g).

Etymology:

It is my pleasure to dedicate the new species to my colleague Jordi Ribes, joining in this way the famous heteropterists Izyaslav M. Kerzhner and Pavel Štys who already have their own Triplatyx .

Collecting circumstances:

Unknown.

Distribution:

Known only from the type locality situated near western coast of the island. Discovery of Triplatyx ribesi sp. nov. much complicate the species identification within T. quadraticeps species-group, making the females practically unidentifiable. In this light the female-only based distributional records of T. dubius given by Kment (2008) must be considered as tentative, as both T. dubius and T. ribesi sp. nov. seem to co-occur in Toliara province (see Fig. 4).