Hydrometra nicobarensis, Jehamalar, E. Eyarin & Chandra, Kailash, 2014

Jehamalar, E. Eyarin & Chandra, Kailash, 2014, On the genus Hydrometra Latreille (Hemiptera: Heteroptera: Hydrometridae) from India with description of two new species, Zootaxa 3779 (5), pp. 501-517 : 512-514

publication ID	https://doi.org/ 10.11646/zootaxa.3779.5.1
publication LSID	lsid:zoobank.org:pub:6B08D969-5277-4CFE-8F90-DAB07755D272
DOI	https://doi.org/10.5281/zenodo.6124817
persistent identifier	https://treatment.plazi.org/id/0B5E8796-FFBE-FF8C-AE96-0164FBC08133
treatment provided by	Plazi
scientific name	Hydrometra nicobarensis
status	sp. nov.

Treatment

Hydrometra nicobarensis View in CoL sp. nov.

( Figs. 1G–H View FIGURES 1 A – H , 2G–H View FIGURES 2 A – H , 3G–H View FIGURES 3 A – H , 4G–H View FIGURES 4 A – H , 5G–H View FIGURES 5 A – H )

Material examined. Holotype. ♂ (brapt.): INDIA, ANDAMAN AND NICOBAR ISLANDS, Nicobar District, Great Nicobar Island, GNBR, Lakshmi Nagar, 274 ft, N 6°51.712’, E 93°53.261’, 27.iii.2012, Coll. E. Eyarin Jehamalar. Allotype. ♀ (brapt.), same data as for holotype. Paratypes. 4 ♂ (brapt.), 3 ♀ (brapt.), 1 ♀ (mac.), 1 immature, same data as for holotype. 1 ♀ (mac.), GNBR, Chingen Village, 38 ft, N 6°58.473’, E 93°55.548’, 8.xi.2010; 1 ♂ (brapt.), GNBR, Chingen Village, 15 ft, N 6°58.390’, E 93°55.612’, 29.iii.2012; 1 ♂ (brapt.), GNBR, Afra Bay, 7 ft, N 7°11.094’, E 93°43.563’, 13.iv.2012; 1 ♂ (brapt.), GNBR, Afra Bay, 124 ft, N 7°10.874’, E 93°44.093’, 14.iv.2012. All the examined materials were collected from slow running streams with marginal vegetation on marsh land by E. Eyarin Jehamalar.

Repository. The type specimens are deposited in the CEL, ZSI, New Alipore, Kolkata, West Bengal, India. Holotype Reg. No. 3234/H15, Allotype Reg. No. 3235/H15 and Paratypes Reg. No. 3236/H15 to 3240/H15.

Etymology. The name nicobarensis refers to the type locality Great Nicobar Island.

Diagnosis. H. nicobarensis can easily be identified by the following characters: anteclypeus conical, with blunt tip ( Fig. 2H View FIGURES 2 A – H ); pronotal lobe of brachypterous form distinctly sinuated laterally between prothorax and mesothorax in both sexes ( Figs. 1G, H View FIGURES 1 A – H ); presence of setal patch on the postero-sublateral region of sternum VII and the presence of dispersed setae on posterior part of sternum VI and anterior part of sternum VII of male ( Figs. 4G View FIGURES 4 A – H , 5G View FIGURES 5 A – H ); sternum VII of male slightly depressed, which is visible only in ventro-lateral aspect; caudal process of both sexes slightly dorsocaudad with the anterior margin curved, in lateral aspect ( Figs. 5G, H View FIGURES 5 A – H ); sternite VIII of female with a subapical shallow notch ( Fig. 5H View FIGURES 5 A – H ); mostly occur in brachypterous form.

Description. Brachypterous male: Holotype: ( Figs. 1G View FIGURES 1 A – H , 2H View FIGURES 2 A – H , 3G View FIGURES 3 A – H , 4G View FIGURES 4 A – H , 5G View FIGURES 5 A – H ). Body length 10.88 (range 10.5– 11.17, n=5); maximum body width (across metacetabula) 0.64 (range 0.63–0.67, n=5).

Colour: Dark brown to black dorsally, paler ventrally; anteclypeus, antennal sockets, antenna, rostrum dark brown and shiny; base of antenna paler; rostrum and legs brown and shiny; pronotal lobe with a distinct median white stripe extends anteriorly near to anterior margin of eyes, but gradually fades from base of head; sublateral region of pronotal lobe brown; wing pads dark brown to black with inner margin with white longitudinal stripe ( Fig. 1G View FIGURES 1 A – H ); abdomen dorsally dark brown to black, mediotergites shiny; setal patch on sternum VII dark brown.

Structural characters: Head length 3.38 mm, maximum head width across eyes 0. 44 mm; head width across antennal tubercle 0.39; anteocular region length 2.31; post ocular region length 0.85; head anterior region with two pairs of trichobothria ( Fig. 2H View FIGURES 2 A – H ), posterior region with one pair of trichobothrium; antennal segment length I–IV 0.55, 1.12, 1.85, 1.20; anteclypeus conical with blunt tip, anteclypeus length along midline 0.30; maxillary plate depressed, in lateral view, partly covering base of gular lobe and not extend beyond anteclypeus and gular lobe in lateral aspect; gular lobe well developed, suboval, not fully covers base of rostrum in lateral aspect ( Fig. 2G View FIGURES 2 A – H ); antennal tubercle length 0.10; antennal tubercle width 0.07; rostrum at rest, reaching just beyond posterior margin of eyes; eye length 0.23, eye width 0.16, dorsal minimum distance between eyes 0.11. Prothorax with a ring of punctures surrounds anterior region of pronotum, posterior part of pronotal lobe with two rows of longitudinal pits on each side, outer row shorter; pronotal lobe length 1.53; distance between proacetabulum and mesoacetabulum 1.03 (measured at middle of each coxa), distance between mesoacetabulum and metacetabulum 1.74, each acetabulum with few pits; prosternal length 0.44, mesosternal length 0.84, metasternal length 1.25; wing strap surpassing base of second tergite. Legs (length, range of 5 specimens is given in parenthesis). Fore leg: femur 2.94 (2.89–3.30), tibia 3.02 (3.02–3.60), tarsus I–III 0.08 (0.05–0.08), 0.31 (0.27–0.34), 0.22 (0.18–0.26); mid leg: femur 3.69 (3.29–3.69), tibia 4.26 (3.73–4.30), tarsus I–III 0.08 (0.05–0.08), 0.45 (0.38–0.46), 0.24 (0.21–0.26); hind leg: femur 4.42 (3.71–4.52), tibia 5.60 (4.74–5.60), tarsus I–III 0.07 (0.07–0.08), 0.28 (0.28–0.43), 0.20 (0.20–0.26); hind femur without specialized fringe of long erected hairs. Abdomen: long and slender, length 4.86; tergite V length 0.75, anterior width of tergite V 0.40; connexivum without characteristic pilosity, connexival corners simple, without prominent characteristic pilosity ( Fig. 3G View FIGURES 3 A – H ); tergite VII and VIII uniformly clothed with short brown hairs; tergite VII elevated posteriorly, tergite VII length 0.44; sternite VII swollen posteriorly, prominent in lateral view; anterior width of medio-tergite VII 0.17, posterior width of medio-tergite VII 0.26; sternite VI posterior part with few long dispersed hairs ventrolaterally continued upto posterior corner of sternite VII; posterior half of sternite VII ventrolaterally with a broad patch of thick, long brown setae continued near to connexival margin laterally ( Fig. 4G View FIGURES 4 A – H ); abdominal segment VIII short and narrow, depressed ventro-laterally, with three long hairs adjacent to ventromedian elevation; caudal process slightly dorsocaudad with convex anterior margin in lateral aspect, tergite VIII length including caudal process 0.52, caudal process length 0.11; length of sternum VIII along mid line 0.22.

Brachypterous female: ( Fig. 1H View FIGURES 1 A – H ). Similar to holotype, but little larger than males, body length 12.01 (range 11.62–12.32, n=4), width at metacetabula 0.72 (0.72–0.76, n=4), head length 3.53, head width maximum at eyes 0.48, width at antennal tubercles 0.44, anteocular length 2.38, postocular length 0.91, dorsal minimum width between eyes 0.14, eye length 0.26, width 0.18; antennal segments length I–IV 0.45, 1.06, 2.28, 1.36; pronotal lobe length 1.64, distance between procoxa and mesocoxa 1.1, distance between mesocoxa and metacoxa 1.77. Legs (length, range of 4 specimens is given in parenthesis). Fore leg: femur 3.3 (3.13–3.37), tibia 3.37 (3.15–3.42), tarsus I–III 0.07 (0.07–0.08), 0.32 (0.28–0.32), 0.22 (0.19–0.22); mid leg: femur 3.69 (3.67–3.81), tibia 4.01, tarsus I–III 0.07 (0.07-0.09), 0.44 (0.41–0.46), 0.25 (0.22-0.25); hind leg: femur 4.51 (3.92–4.51), tibia 5.23 (5.2–5.62), tarsus I–III 0.06 (0.06–0.08), 0.39 (0.34–0.41), 0.24 (0.22–0.24). Wings surpassing anterior margin of tergite II. Abdomen inwardly curved in lateral aspect, abdominal length 5.52; tergite V length 0.91, anterior width 0.64; tergite VII and VIII clothed with brown setae as in males; connexival corners not produced, connexival margin without specialized setae ( Fig. 4H View FIGURES 4 A – H ); tergite VII slightly raised posteriorly, length of tergite VII 0.54, posterior mediotergite width 0.19, less than anterior mediotergite width 0.22; sternite VII length 0.75, sternite VII produced postero-medially ( Fig. 4H View FIGURES 4 A – H ), covering more than half of gonocoxae medially, subapex of sternum VII slightly depressed, prominent in lateral view ( Figs. 4H View FIGURES 4 A – H , 5H View FIGURES 5 A – H ); gonocoxae length along midline 0.02; tergite VIII length including caudal process 0.37, caudal process length 0.11; caudal process dorsocaudad, tip pointed, distinctly curved near apex, convexed anteriorly in lateral aspect.

Macropterous female: Similar to holotype and brachypterous female. Body length 11.7–11.88 (n=2), width at metacetabula 0.71–0.74 (n=2); maximum head width at eyes 0.48; head width at antennal tubercle 0.44; anteocular length 2.36, postocular length 0.93; eye length 0.26, width 0.17; pronotal lobe length 1.90; distance between procoxa and mesocoxa 1.19, between mesocoxa and metacoxa 1.80; antennal length I–IV 0.41, 1.36, 2.67, 1.18. Legs. Fore leg: femur 3.30, tibia 3.61, tarsus I–III 0.08, 0.32, 0.21; mid leg: femur 3.66, tibia 4.03, tarsus I–III 0.09, 0.46, 0.23; hind leg: femur 4.25, tibia 4.30, tarsus I–III 0.07, 0.34, 0.22. Wings reaching middle of tergite V; abdomen length 5.50; anterior width of medio tergite VII 0.22, posterior width of mediotergite VII 0.21; sternite VII length 0.60; gonocoxae length 0.02.

Comparative notes. H. nicobarensis sp. nov. is closely related to H. borneensis Zettel & Yang, 2004 . The hind femur of male H. borneensis is fringed with long, erect hairs, which are absent in male H. nicobarensis . The posterior setal patch on sternum VII of H. nicobarensis is almost similar to H. borneensis ; however, in H. nicobarensis in addition to the posterior setal patch some dispersed setae are also present in the anterior region of sternum VII, which extend to the posterior half of sternum VI, very prominent in alcohol; these dispersed setae are absent in H. borneensis . Some variation was noticed in the position of the caudal process of the females of H. nicobarensis within the same population; the caudal process of female H. borneensis is distinctly erected upwards, however, in H. nicobarensis the caudal process is not erected upwards, except for two brachypterous females, the caudal process is erected upwards. The subapical depression of sternum VII of females is shallow and half-circle shaped in ventral aspect in H. nicobarensis , but, in H. borneensis it is deep and half-ovate.