Tenagogonus ceylonensis Hungerford & Matsuda

Jehamalar, E. Eyarin & Chandra, Kailash, 2013, On the genus Tenagogonus Stål (Hemiptera: Heteroptera: Gerridae) from India with a description of a new species, Zootaxa 3616 (4), pp. 378-386 : 379-386

Tenagogonus ceylonensis Hungerford & Matsuda

Figs. 1 I, 2A, D, G, J, 3A

Tenagogonus ceylonensis Hungerford & Matsuda, 1962: 141 .

Material examined. INDIA: Tamil Nadu, Kanyakumari District, Cherukole Village, 131 ft [39.9 m], N 08°18’17.9’’, E 077°15’33.6’’, 20.v.2011, Coll: E. Eyarin Jehamalar, 8 3 (apt.), 1 Ƥ (apt.) (ZSI Reg. No. 2720/ H15).

Diagnosis. Apterous form: Male mean length 4.49, range 4.40–4.59 (n=5), mean width 1.6, range 1.49–1.6 (n=5), and female length 5.27 (n=1) excluding lateral processes of seventh segment (= connexival spines), width 1.98 (n=1); colour: Ochraceous; head with four stripes, central pair of stripes united at base and slightly pale; each fourth antennal segment longer than other segments; antero-sublateral region of anterior pronotal lobe with short broad band on each side; pronotal lobe with median brown stripe; mesopleuron with three brown longitudinal stripes and white fascia near each side of pronotal lobe; male devoid of connexival spines and females with long connexival spines, converging on dry specimen ( Fig. 2 G); posterior margin of eighth sternum of male bisinuated ( Figs. 1 I, 2J); endosomal sclerites as in Figs. 2A, D .

Distribution. India (Karnataka, Kerala, and Tamil Nadu), Sri Lanka.

Remarks. In the original description of the species, the venter of the mesonotum was described as nearly black, but the specimens studied in this study have the venter pale yellow and clothed with minute brown hairs. These specimens represent the first record for this species for Tamil Nadu.

Tenagogonus nicobarensis Andersen Figs. 1J, 2B, E, H, K, 3B

Tenagogonus nicobarensis Andersen, 1964: 322 .

Material examined. INDIA: Andaman and Nicobar Islands, South Andaman: Manjery, 199 ft [60.6 m], N 11°32.919’, E 92°39.423’, 3.iii.2012, 1 3 (mac.), 3 Ƥ (mac.); Wandoor, 187 ft [57.0 m], N 11°35.816’, E 92°37.581’, 5.iii.2012, 3 3 (apt.), 6 Ƥ (apt.); Humphrygunj, 292 ft [89.0 m], N 11°85.117’, E 92°39.453’, 6.iii.2012, 3 3 (apt.), 3 3 (mac.), 2 Ƥ (apt.), 2 Ƥ (mac.); Mongulton, 46 ft [14.0 m], N 11°34.810’, E 92°39.297’, 6.iii.2012, 3 3 (apt.), 4 3 (mac.), 10 Ƥ (apt.); Guptapara, 72 ft [21.9 m], N 11°34.448’, E 92°39.969’, 6.iii.2012, 1 m (mac.); Bambooflat, 203 ft [61.9 m], N 11°43.141’, E 92°43.177’, 7.iii.2012, 3 3 (apt.), 4 Ƥ (apt.); Shoalbay, 93 ft [28.3 m], N 11°49.545’, E 92°43.638’, 14.iii.2012, 6 3 (apt.), 3 3 (mac.), 3 Ƥ (apt.), 1 Ƥ (mac.). All specimens were collected from streams of INDIA, Andaman & Nicobar Islands, South Andaman, by E. Eyarin Jehamalar and all specimens are deposited in ZSI Kolkata, Reg. No. 2693/H15 to 2699/H15.

Diagnosis. Apterous form: Male mean length 6.38, range 5.40–7.57 (n=5), mean width 2.01, range 1.60–2.5 (n=5), and female mean length 7.07, range 6.75–7.43 (n=5), mean width 2.46, range 2.17–2.67 (n=5); colour yellowish brown; head with four black stripes; mesopleuron with two black stripes, outer one broad; lateral region of mesosternum with interrupted black band; male devoid of lateral processes of seventh sternum (= connexival spines) and female with long connexival processes ( Fig. 2 H, 3B); seventh abdominal sternum of male with Vshaped impression on its posterior margin ( Figs. 2 K); ninth sternum of male with two sheath-like structures leaving a broad median longitudinal depression widened anteriorly; endosomal sclerites as in Figs. 2B , E; macropterous form: Male mean length 7.38, range 6.59–8.32 (n=4), mean width 2.10, range 1.77–2.44 (n=4), and female mean length 7.52, range 7.26–7.91 (n=4), mean width 2.48, range 2.34–2.72 (n=4).

Distribution. Andaman & Nicobar Islands

Remarks. This species has been reported from the Andaman Islands and a few Nicobar groups of Islands, but during our extensive surveys, T. nicobarensis has not been encountered by us from Great Nicobar Island.

Tenagogonus venkataramani sp. nov. ( Figs. 1A–H , 2C , F, I, L, 3C)

Material examined. Holotype. 3 (apt.): INDIA, Andaman & Nicobar Islands, Great Nicobar Island, GNBR, Govind Nagar, Nature Trail, 348 ft [106.1 m], N 07°00.202’, E 093°52.821’, 10.xi.2010, Coll: E. Eyarin Jehamalar. Paratypes. Same data as for holotype, 1 Ƥ (apt.). Govind Nagar, East West Road, 272 ft [82.9 m], N 07°00.108’, E 093°52.877’, 6.xi.2010, 5 3 (apt.), 2 Ƥ (apt.); Johinder Nagar, Chingen Village, 8.xi.2010, 38 ft [11.6 m] N 06°58.473’, E 093°55.548’, 12 3 (apt.), 2 Ƥ (mac.), 3 Ƥ (apt.); Laxmi Nagar, N 6°54.034’, E 93°53.471’, 23.iii.2012, 3 3 (apt.); Sastri Nagar, N 6°48.352’, E 93°53.297, 24.iii.2012, 6 3 (apt.), 4 Ƥ (apt.), 1 Ƥ (mac.); Gandhi Nagar, N 6°50.215’, E 93°53.181’, 25.iii.2012, 4 3 (apt.), 2 Ƥ (apt.); Magar Nalah, N 06°59.320’, E 093°54.578’, 28.iii.2012, 1 3 (apt.); East West Road 19th Km, Galathea tributary, N 06°57.997’, E 093°49.545’, 3.iv.2012, 2 3 (apt.), 1 Ƥ (apt.); Afra Bay, N 07°91.040’, E 93°44.184’, 15.iv.2012, 9 3 (apt.), 2 Ƥ (apt.). All specimens were collected from streams of INDIA, Andaman & Nicobar Islands, Nicobar, GNBR, by E. Eyarin Jehamalar.

Repository. The type specimens are deposited in the Central Entomological Laboratory of Zoological Survey of India, New Alipore, Kolkata, West Bengal, India. Holotype Reg. No. 2748/H15, Paratypes Reg. No. 2749/H15 to 2757/H15.

Etymology. Tenagogonus venkataramani sp. nov. is named in honour of Dr. K. Venkataraman, Director, Zoological Survey of India, New Alipore, Kolkata.

Diagnosis. Tenagogonus venkataramani sp. nov. can easily be identified by the presence of an almost parallelsided, broad deep groove ventrally in the middle of the first genital segment (eighth abdominal segment) and the contiguous longitudinal setal tufts ( Figs. 1B ; 2L). The seventh sternum of the female has a median apical projection and flap-like apical connexival projections laterally.

Description. Apterous male (holotype) ( Figs. 1A, B, D ) Body length 5.82, width (across mesoacetabula) 1.93. Body narrower than female.

Colour. Yellowish brown with piceous to black stripes; antennae and legs fuscous; apices of femora, tibiae and tarsi dark; omphalium and surrounding area pale red; body venter pinkish yellow.

Structural characters

Head. Length: Head 0.94, antennal segments one to four 1.78, 1.55, 2.01, 3.01; rostral segments one to four 0.31, 0.16, 1.64, 0.34. Width: Head 1.29; head width between eyes 0.69. Head with pair of lateral shorter stripes and central longer V-shaped stripe, no stripes uniting anteriorly ( Fig. 1A ). Subapex medially with pair of piceous spots covered by brown hue. Antennae much longer than body. Rostrum reaching to middle of mesosternum ( Fig. 1B ); apical flap of third rostral segment and fourth rostral segment fully black and shiny.

Thorax. Length: Anterior pronotal lobe 0.61; pronotal lobe 2.52; prosternum 0.58; mesosternum 2.41, metasternum 0.45; fore femora 2.39; fore tibia 2.14; fore tarsus I 0.19; fore tarsus II 0.26; mid femora 6.18; mid tibia 4.33; mid tarsus I 1.98; mid tarsus II 0.43; hind femora 6.08; hind tibia 2.74; hind tarsus I 0.51; hind tarsus II 0.35. Width: Pronotal lobe 0.96; fore femora 0.24, mid femora 0.17, hind femora 0.13. Pronotum and mesonotum with median and marginal stripes; mesopleuron with distinct stripe very close to pronotal lobe and obscure stripe on middle of mesopleuron; black stripe on sublateral region of mesosternum originating near base of fore trochanter and reaching near anterior region of mesoacetabular groove and not interrupted medially ( Fig. 1D ); piceous spot on mesoacetabula open anteriorly; indistinct stripe on sublateral region of mesonotum brown; metacetabulum near to connexivum with curved piceous stripe; posterior margin of metasternum slightly sinuated laterally and convexed at middle; omphalium protruding just above posterior margin of metasternum, surrounded with pale reddish hue; stripe on metanotum not reaching posterior margin; W-shaped marking between metanotum and first abdominal tergite black. Legs. Fore femora and fore tibiae slightly curved; apex of each middle femur with small spine; apices of hind coxae near fifth abdominal sternum.

Abdomen. Nine abdominal tergites visible from above; length of tergites one to nine, respectively, 0.34, 0.22, 0.15, 0.14, 0.12, 0.18, 0.39, 0.27, 0.09; abdominal sternal length two to nine, respectively, 0.12, 0.08, 0.08, 0.08, 0.10, 0.27, 0.24, 0.44. Abdominal tergites one to two with broad piceous band medially enclosing yellow spot; tergite three with pair of narrow piceous stripes; tergites four to seven each with pair of small piceous spots anteriorly; tergite seven with pair of longitudinal linear streaks laterally near connexiva; intersegmental regions of connexiva each with piceous spot; abdominal sternum eight with tuft of brownish yellow setae on each side of the median longitudinal groove. ( Figs. 1B, H ; 2L); posterior margin of eighth abdominal segment slightly trisinuate; anterior region of ninth abdominal sternum fuscous, shiny and downwardly sloped; connexiva not produced apically; parameres very small and oval; reticulation seen on endosoma; dorsal sclerite of endosoma curved, pair of lateral sclerites encircling dorsal region of endosoma ( Fig. 2 F); ventral sclerite broad and excavated anteriorly ( Fig. 2C ).

Apterous female (Paratypes) ( Figs. 1C, F ). Mean body length 6.52, range 5.88–7.25 (n=5), width (across mesoacetabula) 2.41, range 2.13–2.76 (n=5).

Colour. Similar to apterous male except the colour pattern of mesopleura and mesoacetabulum. The stripe on middle of the mesopleuron thick, broad, and connected with the lateral stripe of pronotum. The short stripes on the dorsal side of mesoacetabulum is enclosed a small yellow spot.

Structural characters (range is given in parenthesis)

Head. Mean length (n=5): Head 1.0 (0.93–1.03), antennal segments one to four, respectively, 1.57(1.45–1.72), 1.38 (1.23–1.47), 1.76 (1.57–1.91), 2.68 (2.41–2.85); rostral segments three and four, respectively, 1.82 (1.37–1.82) and 0.42 (0.36–0.49). Mean width (n=5): Head 1.30 (1.23–1.43), width between eyes 0.65 (0.56–0.73). Other characters as for holotype.

Thorax. Mean length (n=5): Anterior pronotal lobe 0.66 (0.60–0.68); pronotal lobe 2.67 (2.43–2.96); prosternum 0.52 (0.45–0.58); mesosternum 2.51(2.28–3.01), metasternum 0.55 (0.47–0.61); maximum width of pronotal lobe 1.09 (0.95–1.25). Mesopleuron with two distinct stripes, one very close to pronotal lobe and another on middle of mesopleuron anteriorly attached with contiguous stripe; large piceous spot on mesoacetabula enclosing oblique yellow to orange spot; posterior margin of metasternum not strongly bisinuate; fore femora and fore tibiae straight; apices of middle femora without spines; hind coxae surpassing third abdominal sternum; all other characters similar to those of holotype; leg measurements in Table 1 .

Abdomen. Eight tergites visible from above; mean length of tergites one to eight, respectively, 0.39 (0.32–0.51), 0.26 (0.21–0.32), 0.24 (0.18–0.28), 0.22 (0.19–0.25), 0.22 (0.2–0.25), 0.28 (0.23–0.30), 0.43 (0.41–0.44) (n=5). Mean length of sternites two to seven, respectively, 0.24 (0.22–0.27), 0.23 (0.19–0.25), 0.24 (0.22–0.27), 0.25 (0.23–0.27), 0.31 (0.26–0.34), 0.67 (0.62–0.72) (n=5). Tergites one to three with broad piceous band medially enclosing yellow spot, intersegmental region between tergites four and five with pair of piceous spots; anterior region of tergite six with pair of round piceous stripes, tergite seven laterally near connexiva with thick piceous stripe on each side; connexiva each with broad piceous stripe; posterior margin of tergite seven slightly concave; venter of abdomen paler; posterior margin of seventh sternum strongly bisinuate, with median triangular projection; connexiva apically produced into flap-like projections ( Figs. 1G , 2 I & 3C); genital segments well retracted into abdomen.

Macropterous female ( Fig. 1E ). Mean body length 6.71 (6.42–6.93) (n=3), width (across mesoacetabula) 2.27 (2.16–2.33) (n=3).

Colour. Same as that of apterous female.

Structural Characters

Head. Mean length (n=3): Head 0.94 (0.80–1.03), antennal segments one to four, respectively, 1.70 (1.68–1.70), 1.38 (1.29–1.47), 1.76 (1.65–1.86), 2.70 (2.47–2.84); rostral segments three and four, respectively, 1.60 (1.55–1.66) and 0.44 (0.43–0.0.45). Mean width (n=3): Head 1.30 (1.27–1.31), width between eyes 0.67 (0.61–0.71). Other characters as for holotype.

Thorax. Mean anterior pronotal lobe 0.56 (0.53–0.59); pronotal lobe length 2.58 (2.38–2.71) (n=3), width across humeral angle 1.71 (1.68–1.75) (n=3); hemelytral length 3.95 (3.83–4.12) (n=3), maximum width 1.09 (1.05–1.12) (n=3). Hemelytra cinerous brown; all other characters same as those of apterous paratype. Abdomen. Same as that of apterous paratype.

Discussion

The male of T. venkataramani sp. nov. is closely related to T. nicobarensis Andersen, T. maai Hungerford & Matsuda, and T. akanthinos Chen & Nieser in having the broad deep median longitudinal depression on the venter of the first genital segment and the absence of setal tufts on the sides of the pygophore (ninth abdominal segment). However, this new species can be differentiated from T. nicobarensis by the absence of the V-shaped impression on abdominal sternite VII. The new species shares one character with T. akanthinos and T. maai : the abdominal segment VIII has a broad median longitudinal groove. This groove is bordered by slightly diverging carinae in T. akanthinos , but in T. venkataramani sp. nov. and T. maai the carinae are straight. However, it can be differentiated with T. maai by the presence of the tuft of setae on the carinae. The females of T. maai and T. akanthinos have short and pointed connexival spine, whereas these connexival spines are flap-like and blunt in T. venkataramani , and long and blunt in T. nicobarensis .

A total of 121 specimens from 17 localities of 3 species of Tenagogonus were examined in the present study (61 T. venkataramani sp. nov., 51 T. nicobarensis , 10 T. ceylonensis ). Of the three species, only a small number of T. ceylonensis were collected from a single site in an agricultural area (monoculture rubber plantation). The distribution maps of known Indian species of Tenagogonus are provided in Figs. 3 D and 4.

Figures

FIGURE 1. A – H, T. venkataramani sp. nov.: A, male (holotype), dorsal view; B, same, ventral view; C, female (paratype), dorsal view; D, male (holotype), left lateral view; E, macropterous female (paratype), dorsal view; F, apterous female (paratype), left lateral view; G, apterous female (paratype), terminal abdominal segments, ventral view; H, male (holotype), genital segments, left lateral view; I, T. ceylonensis, apterous male genital segments, left lateral view; J, T. nicobarensis, same.

FIGURE 2. A, D, G, J, T. ceylonensis: A, pygophore, parameres and endosoma, ventral view; D, endosoma, right lateral view; G, terminal abdominal segment of female showing connexival spines, dorsal view; J, male genital segments, ventral view. B, E, H, K, T. nicobarensis: B, pygophore, parameres and endosoma, ventral view; E, endosoma, right lateral view; H, terminal abdominal segment of female showing connexival spines, dorsal view; K, male genital segments, ventral view. C, F, I, L, T. venkataramani: C, pygophore, parameres and endosoma, ventral view; F, endosoma, right lateral view; I, terminal abdominal segment of female showing connexival spines, dorsal view; L, male genital segments, ventral view (ds—dorsal sclerite, en—endosoma, ls—lateral sclerite, pa—paramere, pg—pygophore, vs—ventral sclerite).

FIGURE 3. A, B, C, Female terminal abdominal segments showing connexival spines, lateral view; A, T. ceylonensis; B, T. nicobarensis; C, T. venkataramani. Distribution of T. ceylonensis. Round dots denote records from literature and the star denotes the present record from Tamil Nadu.

Tables

TABLE 1. Mean length of legs (in mm. n = 5), range is given in parenthesis.

Paratypes	Leg parts	Femur Tibia	I Tarsal segment	II Tarsal segment
Apterous males	Fore leg Mid leg	2.26 (2.18–2.39) 2.07 (1.98–2.14) 5.84 (5.59–6.18) 4.22 (3.99–4.35)	0.20 (0.17–0.24) 1.75 (1.58–1.98)	0.34 (0.26–0.41) 0.43 (0.4–0.45)
	Hind leg	5.81 (5.52–6.08) 2.60 (2.45–2.74)	0.44 (0.4–0.51)	0.35 (0.31–0.36)
Apterous females	Fore leg Mid leg	2.60 (2.16–2.98) 2.32 (2.09–2.64) 6.47 (6–6.99) 4.89 (4.38–5.69)	0.25 (0.21–0.30) 2.05 (1.76–2.5)	0.40 (0.28–0.45) 0.49 (0.46–0.51)
	Hind leg	6.45 (5.91–7.06) 3.13 (2.89–3.42)	0.58 (0.52–0.62)	0.42 (0.35–0.47)