Mesovelia occulta, Jehamalar & Chandra & Polhemus, 2019

Jehamalar, E. Eyarin, Chandra, Kailash & Polhemus, Dan A., 2019, Review of the Mesovelia horvathi species complex (Hemiptera: Gerromorpha: Mesoveliidae), with the description of seven new species from India, Zootaxa 4651 (3), pp. 471-496 : 481-482

Mesovelia occulta sp. nov.

( Figs. 4 A–K)

Material examined. Holotype (apterous ♂): INDIA, TAMIL NADU, Kanyakumari District, Chithiramcode Village , irrigation ditch beside rubber plantation, 66 m a.s.l., 8.31289 0 N, 77.32061 0 E, 23.x.2012, Coll. E.E. Jehamalar & E. Hallings. Paratypes: 9 apt. ♂, 3 apt. ♀, same locality data as for Holotype. 1 apt. ♂, 1 apt. ♀, Nagercoil, Scott Christian College, Pond , 60 m a.s.l., 8.18283 0 N, 77.40564 0 E, 13.iii.2008, Coll. E.E. Jehamalar ; Cherukole Village , 1 apt. ♀, 40 m a.s.l., 8.30497 0 N, 77.25933 0 E, 3.x.2011 ., 1 apt. ♂, 2 apt. ♀, 2 mac-da ♀, 9.i.2013, Coll. E.E. Jeha- malar & E. Hallings; 2 apt. ♀, Keeriparai , 96 m a.s.l., 8.39628 0 N, 77.41039 0 E, 26.x.2012, Coll. E.E. Jehamalar.

Repository. The type specimens are deposited in the CEL, ZSI, New Alipore, Kolkata, West Bengal, India. Holotype Reg. No. 8324/H15 and Paratypes Reg. No. 8325/H15 to 8330/H15.

Etymology: The word occulta is derived from the Latin adjective “occultus,” meaning hidden, and refers to spiniform setal tuft on the sternum VIII of male being hidden within sternum VII.

Diagnosis. This species can easily be identified by the pair of spiniform setal tufts with 3–5 spiniform setae on each tuft on abdominal sternum VIII in the male ( Fig. 4F ); these are completely covered by sternum VII when the abdomen is not distended, and are thus inconspicuous in dry-mounted specimens. The peculiar shape of male paramere, with its long apical arm ( Fig. 4K ), and the absence of spines on the flexor regions of all femora are also diagnostic.

Description. Apterous male (holotype): ( Figs. 4A, E , G–K). Body length 1.87 (1.80–1.90, n=5), body width at metanotum 0.50 (0.50–0.52, n=5), body width at tergum IV 0.50 (0.50–0.52, n=5).

Colour. Yellowish brown; eyes black, antenna dark brown, fourth rostral segment black except base brown; femora of all legs subapically brown, claws of legs, setiform spines on appendages, black; collar of pronotum yellowish brown, a pair of medium sized spiniform setal tufts on abdominal sternum VIII, dark brown to black; connexival lateral margin brown to black, meso- and metanota and terga I–IV submedially with brown mark, posterior margin of tergum VII brown, anterior region of terga II and III medially with two indistinct brown mark; connexival suture ventrolaterally with two brown lines.

Structural characters. Body and appendages clothed with dark brown, minute setae except terga medially bare and shiny; head with indistinct median longitudinal impression, frontoclypeal region with seven thick bristles, posterior inner margin of eye slanting. Head length 0.26, head width across eyes 0.44; synthlipsis 0.18; eye length 0.16, eye width 0.11. Lengths of antennomeres I–IV 0.36, 0.33, 0.72, 0.66.

Pronotal length 0.16, width 0.47; mesonotal length 0.19, width 0.51; metanotal length 0.13, width 0.5. Anterolateral region of pronotum round, posterolateral region concaved; posteromedially slightly concaved; mesonotum posteromedially produced, posterior margin of metanotum straight ( Fig. 4A ). Lengths of leg segments: foreleg: femur 0.65, tibia 0.57, tarsomeres I–III 0.03, 0.07, 0.09; mid leg: femur 0.82, tibia 0.77, tarsomeres I–III 0.04, 0.15, 0.12; hind leg: femur 1.05, tibia 1.30, tarsomeres I–III 0.05, 0.22, 0.15. Widths of fore, mid, hind femora 0.10, 0.11, 0.12. Flexor region of femora of all legs without any spines; flexor region of fore and mid femora with fringe of fine short setae; extensor subbasal region of mid tibia without distinct spine; flexor region of mid tibia apical region with four short evenly distributed swimming setae length decreased from anterior to posterior; hind tibia sparsely clothed with medium sized spines; flexor region of second hind tarsomere with three evenly spaced thin, short brown setae. Basal third of hind femur dorsally bare.

Length of abdominal tergum 1.11; intersegmental suture between abdominal terga I–II medially indistinct; lengths of abdominal terga I–VIII, 0.10, 0.12, 0.11, 0.11, 0.11, 0.13, 0.19, 0.18, abdominal sterna VI–VIII, 0.12, 0.16, 0.10, pygophore 0.18, combined length of abdominal sterna VI–VII 0.28. Basal region of sternum VIII sublaterally with pair of brown to black spiniform setal tufts, each setal tuft with 3–5 spiniform setae ( Fig. 4F, G ), spiniform setal tufts hidden beneath sternum VII; sternum VIII midlaterally at the level of posterior margin with very small tubercle (more evident in alcohol after dissection), sternum VIII posterolaterally excavated; inner length of spiniform setal tuft on sternum VIII 0.06, width 0.01, width between two tufts 0.16; length of sternum VI to abdominal tip 0.58. Terminalia: length of pygophore 0.18, anterior part of proctiger slightly longer than bowl-shaped posterior part, clothed with long setae posteriorly and laterally, median lateral process long with abruptly tapered apex, posterior part ventromedially convex, sometimes with small notch ( Fig. 4H ); pygophore as in Figs. 4I, J ; paramere with sparse setae except apex without setae, paramere broad basally, gradually tapered and bent towards apex, apical part longer than basal part ( Fig. 4K ), paramere when attached to pygophore apical part slightly curved and directed anterolaterad in lateral view ( Fig. 4J ) and in dorsal view tip directed anterad and blunt ( Fig. 4I ).

Apterous female (paratype): ( Figs. 4B, D ). Colour: similar to apterous male, except dark brown mark on abdomen wide ( Fig. 4B ). Body length 2.30 (1.98–2.31, n=5), width across metanotum 0.65 (0.55–0.66, n=5), width across tergum IV 0.77 (0.73–0.81, n=5), head length 0.34, head width 0.49, eye length 0.18, eye width 0.12, synthlipsis 0.21; lengths of antennomeres I–IV 0.39, 0.32, 0.67, 0.66; pronotal length 0.18, width 0.55, mesonotal length 0.20, width 0.60, metanotal length 0.13, width 0.65. Lengths of leg segments: foreleg: femur 0.61, tibia 0.55, tarsomeres I–III 0.04, 0.06, 0.08; mid leg: femur 0.83, tibia 0.82, tarsomeres I–III 0.06, 0.14, 0.13; hind leg: femur 1.10, tibia 1.44, tarsomeres I–III 0.05, 0.22, 0.15. Widths of fore, mid, hind femora 0.09, 0.11, 0.13; flexor region of femora of all legs without any spines.

Dorsal abdominal length 1.46, lengths of abdominal terga I–VIII, 0.16, 0.15, 0.15, 0.14, 0.15, 0.18, 0.22, 0.19; proctiger 0.12, abdominal sterna IV–VII, 0.11, 0.11, 0.09, 0.17, VIII +IX 0.61; combined length of abdominal sterna V–VII 0.37; maximum connexivum width at tergum IV 0.14, ventral abdominal length from sternum V to abdominal tip 0.98.

Macropterous dealated female (paratype): ( Fig. 4C ). Body length to abdominal apex 2.29 (2.29–2.36, n=2), body width at humeral angle 0.68 (0.68–0.71, n=2), width across tergum IV 0.73 (0.73–0.74, n=2).

Colour. Yellowish brown; pronotum brown except posterior lobe posteriorly dark brown; mesoscutellum yellowish brown except laterally dark brown, metanotal elevation dark brown to black except anteromedially yellowish brown; first basal cell (bc-I) (subcostal cell) and apical cell of hemelytra pale brown; second basal cell (bc-II) white with brown hue; anal veinless part of hemelytra dark brown except area adjacent to bc-II and mesoscutellum white beyond apex of metanotal elevation ( Fig. 4C ).

Structural characters. Lengths of anterior pronotal lobe 0.13, posterior pronotal lobe 0.35, mesoscutellum 0.12, metanotal elevation 0.09, hemelytra to vein tip 1.03. Other characters similar to apterous female.

Distribution. Presently known only from Kanyakumari District, Tamil Nadu, India ( Fig. 9D ).

Comparative notes. See under comparative notes of M. brevia .

Figures

FIGURES 4A–K. Mesovelia occulta sp. nov. (A, E, G–K holotype; B, C, D, F, paratype): A, apterous male, dorsal view; B, apterous female, dorsal view; C, macropterous female with forewing membrane broken off, dorsal view; D, abdominal apex of apterous female, ventral view; E, fore leg of apterous male, ventral view; F, eighth abdominal segment of apterous male, ventrolateral view; G, eighth abdominal segment of apterous male, lateral view; H, proctiger of apterous male, ventral view; I, genital capsule of apterous male, dorsal view; J, same, lateral view; K, paramere of apterous male, lateral view (dmp—dorsomedian projection of pygophore; lex—lateral excavation; lp—lateral process; pa—paramere; pr—proctiger; py—pygophore).

FIGURES 9A–H. Distribution of Mesovelia horvathi species complex in India: A, Map of India; B, Meghalaya with M. bispinosa sp. nov. in red triangles, M. brevia sp. nov. in green square, M. isiasi sp. nov. in green cross; C, Meghalaya with M. dilatata sp. nov. in blue circles; D, Tamil Nadu with M. occulta sp. nov. in green circles, M. tenuia sp. nov. in pink square, M. brevia sp. nov. in green squares; E, Tamil Nadu with M. dilatata sp. nov. in blue circles; F, Andaman and Nicobar Islands with M. andamana sp. nov. in red circles.