Diaphorocoris arunachalami Sites and Zettel

Sites, Robert W. & Zettel, Herbert, 2011, Waterfall-inhabiting Naucoridae (Hemiptera: Heteroptera) of southern India and Sri Lanka: Pogonocaudina Sites and Zettel, n. gen., and a review of Diaphorocoris with descriptions of two new species, Zootaxa 2760, pp. 1-17 : 9-12

Diaphorocoris arunachalami Sites and Zettel , NEW SPECIES

Figs. 9 , 11 , 15 , 17 , 19

Description. Macropterous male. Holotype, length 7.76; maximum width 4.74. Paratype (n = 1), length 7.62; maximum width 4.66. Overall coloration dorsally dark brown with yellowish-brown head, pronotum, exposed connexiva, wide band on and at anterior end of embolium gradually narrowing to obsolescence before costal fracture ( Fig. 9 ); dense, dark punctation on head and pronotum. Ventrally, mostly medium brown, with yellowish laterally on prothorax, embolium, abdomen; and all leg segments except brown pro- and mesocoxae. Head, pronotum, and hemelytra generally covered with very short, clavate setae.

Head length 1.20, maximum width 3.08, synthlipsis at posteromesal corner 1.00, lateral hyperoche with lateral margin shallowly concave; anterior margin of eye ~1.5x width of anterior margin of head laterad of eye; posterolateral part of eye slightly protuberant above level of pronotum; five pairs of setal rosettes bordering inner margin of eyes, anteriormost pair slightly ventrad to anterior margin, posteriormost pair adjacent to mesal margin of eyes; posterior margin of head straight between eyes; labrum subtriangular, with apex broadly rounded and lateral margins straight; antennal proportions 5:7:14:10.

Pronotum broad, 2.8 x as wide as long, length at midline 1.48; maximum width at posterolateral corners 4.28; dark punctation consistent in density almost to lateral margin, scattered clavate setae and elongate, erect, light setae; anterior border between eyes dark brown, with transverse, irregular furrows; anterior half with slight depression at midline not sunken below anterior margin; flattened area adjacent to lateral hyperoche of head; ventrally with yellow lateral coloration extending mesad 2/3 distance to coxal base. Scutellum dark brown with apex yellow, triangular with distinctly sinuate posterolateral margins, punctate, tuberculate, distinctly and broadly tumescent above level of clavus, tumescence diminishing anterolaterally, 1.8x as wide as long, width 2.80, length 1.68, clavate setae concentrated laterally on tumescence and on scutellar apex. Hemelytra finely punctate. Claval commisure length 1.04. Embolium length 3.16 (chord measurement), greatest width 0.72; lateral margin straight in basal half beyond humerus, gently curved in distal half, series of ~35 stout brown spines; scattered clavate setae and elongate, erect setae; yellowish anterior band gradually narrowing posteriorly and becoming obsolete before costal fracture; with mesal incursion of yellowish white into dark brown at level of claval commisure; dark coloration immediately anterior to mesal incursion extending close to lateral margin, separated from margin by distance of 2–3 times the length of a marginal spine ( Fig. 11 ). Metaxyphus broadly elongate, 1.5–2.0x as long as wide, acuminate posteriorly ( Fig. 15 ). Pro- and mesocoxae brown, metacoxae yellow with brown infuscation laterally, all other leg segments yellow. Hind tibia with maximum width 0.35. Other leg measurements as follows: foreleg, femur 1.08, tibia 1.56, tarsomeres 1–2 (0.16, 0.16); middle leg, femur 1.68, tibia 1.20, tarsomeres 1–3 (0.12, 0.24, 0.24); hind leg, femur 2.20, tibia 2.18, tarsomeres 1–3 (0.28, 0.76, 0.70).

Abdomen dorsally with margins of III and IV with 10–14 stout brown spines, with anterior 8–9 directed laterally and posteriormost 2–5 directed dorsally; stout marginal spines of V gradually transition from lateral to dorsal direction; scattered marginal light hairs with weak group of very long hairs ¼ distance from postolateral corner; brown coloration at base of very long hairs connected to dark brown coloration beneath wings by poorly defined brown band across yellow connexivum on III & IV, indistinct on V. Ventrally with heavy marginal spines on III–VI and brush of elongate light colored hairs. Posterior margin of mediosternite III straight, IV–V concave, VI–VIII straight. Strong brush of midventral brown hairs beginning on III and continuing to posterior end of abdomen. Posterior margin of laterosternite V shallowly concave. Aedeagus elongate, linear, right margin straight, left side angled to apex in distal 1/5, finely granulate; parameres punctate, symmetrical, anteromesal corners rounded, mesal margins slightly rounded, posteromesal corners rounded and overlapping concave anterior margin of sternum IX of genital capsule ( Fig. 17 ); pygophore punctate, with fine setae.

Macropterous female. Paratypes (n = 6), length 7.55–8.05 (mean = 7.76); maximum width 4.60–4.85 (mean = 4.70). Similar to male in general structure and coloration except as follows; front tarsus one-segmented; pad of hairs on middle tibia reduced; posterior margin of mediosternite V and VI straight; posterior margin of laterosternite V strongly sinuate; subgenital plate (VII) about as long as wide, lateral margins convergent, posterior margin shallowly concave, posterolateral corners broadly rounded; valvulae extending beyond apex of subgenital plate ( Fig. 19 ).

Diagnosis. Diaphorocoris arunachalami can be recognized by its size, ventral coloration, and shape of the metaxyphus. Specifically it can be distinguished from D. dubreuili by its much smaller size; and from D. kiliyur by the narrower metaxyphus and medium to reddish-brown ventral coloration, whereas D. kiliyur has a wide metaxyphus and dark brown to black ventral coloration. D. arunachalami can be distinguished from D. punctatissimus by the pronotum only shallowly flattened behind the anterior margin, whereas in D. punctatissimus it is broadly sunken below the level of the rounded ridge of the anterior margin; the dark coloration of the embolium immediately anterior to the distal mesal incursion of the yellowish-white marginal coloration extends from the embolar suture well beyond halfway to the lateral margin; and the marginal vestiture of the embolium is a row of short, brown, peg-like spines.

Discussion. This species occurred syntopically with D. kiliyur and Pogonocaudina indica at Kiliyur Waterfall. Specifically, it was found on near-vertical wet rocks among algae and mud where water flow was minimal or undetectable.

Etymology. This species is named for Dr. M. Arunachalam, our colleague at Sri Paramakalyani Centre for Environmental Sciences at Manonmaniam Sundaranar University.

Repositories. The holotype is deposited in the Natural History Museum - Vienna, Austria. Paratypes are deposited in the National Zoological Collection, Zoological Survey of India and Natural History Museum - Vienna.

Material examined. Holotype, macropterous male, and paratypes (2 macropterous males, 6 macropterous females): INDIA: Kerala, 10 km WSW Munnar, 1100 m, Kallar Valley, 10o 03' N 76o 58' E, leg. D. Boukal (50).

Additional material observed. INDIA: Tamil Nadu: Kiliyur Waterfall, Yercaud, N 11o 47.770', E 78 o 12.066', elev. 1188 m, 11 March 2010, L-1129, wet rocks of waterfall.

Figures

FIGURES 9 – 10. Habitus photographs of (9) Diaphorocoris arunachalami n. sp., (10) Diaphorocoris kiliyur n. sp.

FIGURES 11 – 14. Right embolium of macropterous (11) Diaphorocoris arunachalami n. sp., (12) Diaphorocoris dubreuili Montandon, (13) Diaphorocoris kiliyur n. sp., (14) Diaphorocoris punctatissimus (Kirby).

FIGURES 15 – 16. Metaxyphus of (15) Diaphorocoris arunachalami n. sp., (16) Diaphorocoris kiliyur n. sp.

FIGURES 17 – 18. Male genital capsule with aedeagus and parameres of (17) Diaphorocoris arunachalami n. sp., (18) Diaphorocoris kiliyur n. sp.

FIGURES 19 – 20. Ventral aspect of posterior abdominal segments of females of (19) Diaphorocoris arunachalami n. sp., (20) Diaphorocoris kiliyur n. sp.