Mesovelia dilatata, 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 : 478-481

Mesovelia dilatata sp. nov.

( Figs. 3 A–K)

Material examined. Holotype (apterous ♂): INDIA, MEGHALAYA, West Jaintia Hills District, Demthring Village, Laddemthring Pond , 1361 m a.s.l., 25.43447 0 N, 92.18622 0 E, 9.iii.2016 , Coll : E. E. Jehamalar . Paratypes: 1 apterous ♀, same data as for holotype . East Khasi Hills District, 1 apt. ♀, Mawkynrew, Waiong Stream , 1489 m a.s.l., 25.42489 0 N, 92.00619 0 E, 28.ii.2016 . East Garo Hills District, 1 apt. ♂, Warima Village, Simsang River , 268 m a.s.l., 25.56668 0 N, 90.50925 0 E, 20.vi.2016 . West Garo Hills District, 1 mac-da ♀, Dalu Village, Sacred Heart Church, Pond , 29 m a.s.l., 25.21243 0 N, 90.22258 0 E, 10.vi.2016 ; 1 apt. ♂, 1 mac-da ♀, Gambegre Village, Skili Stream , 177 m a.s.l., 25.4343 0 N, 90.14153 0 E, 11.vi.2016 . South West Khasi Hills District, 1 apt. ♂, Largav Village, Stream , 7 m a.s.l., 25.20169 0 N, 91.28093 0 E, 9.iii.2018 . Ri-Bhoi District, 1 mac-da ♂, Umiong Village, Umiong Stream , 310 m a.s.l., 25.89149 0 N, 91.56554 0 E, 23.iii.2018 . All the materials were collected by E. Eyarin Jehamalar. TAMIL NADU, Kanyakumari District, 1 mac-da ♂, Nagercoil, Scott Christian College, Pond , 60 m a.s.l., 8.18283 0 N, 77.40564 0 E, 4.iii.2008 ., 1 apt. ♂, 3 apt. ♀, 13.iii.2008., 1 mac-da ♂, 8.iv.2008, Coll. E.E. Jeha- malar; 1 apt. ♂, 1 apt. ♀, Cherukole Village , 40 m a.s.l., 8.30497 0 N, 77.25933 0 E, 20.x.2012 , Coll. E.E. Jehamalar & J. Easac.

Repository. The type specimens are deposited in the CEL, ZSI, New Alipore, Kolkata, West Bengal, India. Holotype Reg. No. 8312/H15 and Paratypes Reg. No. 8313/H15 to 8323/H15.

Etymology. The name dilatata is derived from a Latin word “dilatatus,” meaning dilated or broad, and refers to the dilated basal part of the male paramere.

Diagnosis. Mesovelia dilatata sp. nov. can be identified by the presence of thin, dense brown setae on the body; the short abdominal sternum VIII; the slightly slanting to straight spiniform setal tufts on the abdominal sternum VIII with 8–9 spiniform setae each ( Fig. 3D ); the dilated basal part (0.06) of the male paramere ( Figs. 3E, J ); and the absence of spines on the flexor regions of all femora.

Description. Apterous male (holotype): ( Figs. 3A, E, F, H, J ). Body length 2.07 (1.78–2.16, n=5); body width at metanotum 0.54 (0.50–0.58, n=5), body width at tergum IV 0.57 (0.47–0.59, n=5).

Colour. Yellowish brown; dorsum of body densely covered with dark brown minute setae, mesonotum, metanotum and abdominal terga I–V with brown marks; eyes black; antenna dark brown; claws of all legs and setiform spines on appendages black; collar of pronotum yellowish brown; dorsolateral region of thorax brown; femora of all legs brown towards apex, tarsal tip of all legs dark brown to black; lateral margin of connexivum, black; anterior region of terga II and III medially with two indistinct brown marks ( Fig. 3A ); spiniform setal tufts on abdominal sternum VIII black.

Structural characters. Head with an indistinct median longitudinal impression; frontoclypeal region with seven thick setae, inner margin of eye round, head clothed with some thin black setae and a few thick black setae, body and appendages densely clothed with very minute black setae. Head length 0.31, head width across eyes 0.46; synthlipsis 0.22; eye length 0.17, eye width 0.11. Second antennomere upper region with few minute short setae, fourth antennomere medially annulated, evident in alcohol. Lengths of antennomeres I–IV, 0.40, 0.20, 0.55, 0.78.

Pronotal length 0.18, width 0.51; mesonotal length 0.18, width 0.55, mesonotal length equal to the length of pronotum; metanotal length 0.12, width 0.55.Anterolateral region of pronotum round, posterior margin of pronotum straight medially, mesonotum posteromedially produced, posterior margin of metanotum straight ( Fig. 3A ). Lengths of leg segments: foreleg: femur 0.72, tibia 0.65, tarsomeres I–III 0.03, 0.06, 0.09; mid leg: femur 0.89, tibia 0.87, tarsomeres I–III 0.05, 0.15, 0.14; hind leg: femur 1.10, tibia 1.43, tarsomeres I–III 0.05, 0.20, 0.16. Widths of fore, mid, hind femora 0.11, 0.12, 0.14. Flexor region of femora of all legs without any spines; one third from base of dorsal hind femur bare; extensor subbasal region of mid tibia without distinct spine; flexor region of mid tibia posteriorly with four short evenly distributed swimming setae length decreased from anterior to posterior; flexor region of second hind tarsomere with three evenly spaced thin short brown setae.

Intersegmental suture between abdominal terga I–III and connexivum indistinct; length of dorsal abdominal tergum 1.25, abdominal terga I–VIII, 0.13, 0.14, 0.13, 0.12, 0.12, 0.13, 0.19, 0.22, abdominal sterna V–VIII, 0.14, 0.15, 0.16, 0.11, combined length of abdominal sterna V–VII 0.44; length of sternum V to abdominal tip 0.81. Basal region of sternum VIII sublaterally with pair of black spiniform setal tufts, each setal tuft with 7–9 spiniform setae ( Fig. 3G ); laterally without fringe of setae, sternum VIII midlaterally at the level of posterior margin with very small tubercle (more evident in alcohol after dissection), posterolaterally excavated; inner length of spiniform setal tuft on sternum VIII 0.07, basal width 0.02, width between two tufts 0.19; without any space between posterior margin of abdominal sternum VII and anterior margin of spiniform setal tuft, base of spiniform setal tuft sometimes slightly hidden beneath sternum VII. Terminalia: length of pygophore 0.24, anterior part of proctiger longer than bowlshaped posterior part, clothed with long setae posteriorly, median lateral process long with acute tip, posterior part ventromedially convex, not excavated ( Fig. 3I ); anterior margin of proctiger irregular, anterior part narrower than posterior part; pygophore as in Figs. 3E, F ; basal part of paramere dilated, apical part suddenly narrowed and with pointed apex, paramere with sparse setae except distal part, without setae ( Fig. 3J ).

Apterous female (paratype): ( Figs. 3B, K ). Colour: similar to apterous male, except dark brown mark on abdomen wide ( Fig. 3B ). Body length 2.46 (2.10–2.46, n=5), width across metanotum 0.65 (0.61–0.65, n=5), width across tergum IV 0.84 (0.62–0.85, n=5), head length 0.44, head width 0.50, eye length 0.17, eye width 0.12, synthlipsis 0.24; lengths of antennomeres I–IV 0.38, 0.30, 0.58, 0.51; pronotal length 0.20, width 0.56; mesonotal length 0.18, width 0.61, metanotal length 0.11, width 0.65. Lengths of leg segments: foreleg: femur 0.75, tibia 0.56, tarsomeres I–III 0.05, 0.05, 0.08; mid leg: femur 0.81, tibia 0.86, tarsomeres I–III 0.05, 0.14, 0.14; hind leg: femur 1.14, tibia 1.41, tarsomeres I–III 0.06, 0.20, 0.17. Widths of fore, mid, hind femora 0.11, 0.12, 0.15. Flexor region of femora of all legs without any spines.

Dorsal abdominal length 1.50, lengths of abdominal terga I–VIII 0.17, 0.16, 0.15, 0.12, 0.15, 0.18, 0.22, 0.19; proctiger length 0.15, lengths of abdominal sterna V–VII 0.13, 0.13, 0.12, combined length of abdominal sterna V–VII 0.38, maximum connexival width at tergum IV 0.21, ventral abdominal length from sternum V to abdominal tip 0.95. Terminalia: gonoplac (gp) clothed with medium sized setae, first gonapophyses (go1) and second gonapophyses (go2) crenulate laterally, go1 not reaching tip of go2, go2 pointed apically, proctiger (pr) posteriorly with long setae ( Fig. 3K ).

Macropterous dealated male (paratype): Body length to abdominal apex 1.88 (1.88–1.94, n=3); body width at humeral angle 0.62 (0.59–0.62, n=3), width across tergum IV 0.52, (0.48–0.52, n=3).

Colour. Yellowish brown, posterior region of pronotum, lateral region of mesoscutellum, metanotal elevation and wing veins dark brown.

Structural characters. Length of anterior pronotal lobe 0.10, length of posterior pronotal lobe 0.26, length of mesoscutellum 0.12, length of metanotal elevation 0.12, humeral angle sinuated; hemelytra with three closed cells, basal two elongated, apical cell very small enclosed by thick veins, hemelytral length to vein tip 0.85. Other characters similar to apterous male.

Macropterous dealated female (paratype): ( Fig. 3C ). Body length to abdominal apex 2.43 (2.31–2.43, n=2), body width at humeral angle 0.74 (0.71–0.74, n=2), width across tergum IV 0.76 (0.76–0.80, n=2).

Colour. Yellowish brown; posterior pronotal lobe brown except with indistinct median longitudinal yellowish brown stripe; humeral angle dark brown; mesoscutellum yellowish brown, metanotal elevation dark brown to black; first basal cell (bc-I) (subcostal cell) and second basal cell (bc-II) of hemelytra brown with white hue, apical cell brown; anal veinless part of hemelytra dark brown except area adjacent to bc-II and mesoscutellum white to apex of metanotal elevation; inter segmental region of terga dark brown ( Fig. 3C ).

Structural characters. Lengths of anterior pronotal lobe 0.14, posterior pronotal lobe 0.36, mesoscutellum 0.13, metanotal elevation 0.09, hemelytra to vein tip 1.05. Other characters similar to apterous male and macropterous dealated female.

Distribution. Presently known from Meghalaya and Tamil Nadu, India ( Figs. 9C, E ).

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

Figures

FIGURES 3A–K. Mesovelia dilatata sp. nov. (A, E, F, H, J, holotype; B, C, D, G, I, K, paratype): A, apterous male, dorsal view; B, apterous female, dorsal view; C, macropterous female with forewing membrane broken off, dorsal view; D, abdominal tip of apterous male, ventral view; E, genital capsule of apterous male, lateral view; F, same, dorsal view; G, eighth abdominal segment of apterous male, ventrolateral view; H, eighth abdominal segment of apterous male, lateral view; I, proctiger of apterous male, ventral view; J, paramere of apterous male, lateral view; K, terminalia of apterous female, lateral view (ab9— ninth abdominal segment; dmp—dorsomedian projection of pygophore; go1—first gonapophyses; go2—second gonapophyses; gp—gonoplac; 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.