Isometrus thwaitesi Pocock, 1897

Kovařík, František, Lowe, Graeme, Ranawana, Kithsiri B., Hoferek, David & Š, V. A., 2016, Scorpions of Sri Lanka (Scorpiones Buthidae, Chaerilidae, Scorpionidae) with description of four new species of the genera Charmus Karsch, 1879 and Reddyanus Vachon, 1972, stat n, Euscorpius 220, pp. 1-133 : 43-47

Isometrus thwaitesi Pocock, 1897

( Figs. 13 , 138–151 , 197 , 223–224 , 239–241, 243–244, 253 , 405–406 , 549, 558–560)

Isometrus thwaitesii Pocock, 1897: 114 .

Isometrus (Isometrus) thwaitesi: Vachon, 1982: 88–90 , figs. 36–39; Fet & Lowe, 2000: 150 (complete reference list until 1998); Kovařík, 2003: 4 ; Kovařík & Ojanguren, 2013: 184, 347, figs. 1260–1263.

= Isometrus (Isometrus) thwaitesi pallidus Lourenço & Huber, 2002: 266 , figs. 1–7 (syn. by Kovařík & Ojanguren, 2013: 184).

TYPE LOCALITY AND TYPE REPOSITORY. Ceylon, now Sri Lanka; BMNH.

MATERIAL EXAMINED. Sri Lanka , Ratnapura District, 2 km S Hayes, 30.XI.1995, 1♀, FKCP, leg. S. Bečvář & Košťál; North Central Province , Polonnaruwa District , near Kaudulla National Park, 08°08'40.6"N 080°51' 04"E, 101 m a.s.l. (Locality 15CF, Fig. 581 ), 23. IV. 2015, 1♂ ( Fig. 150 , 549 ) 1♀ ( Fig. 151 ), FKCP, leg. Kovařík et al.; Northern Province , Mannar District , Madhu Road, 08°48'26.3"N 080°10'26"E, 90 m a.s.l. (Locality 15 CH, Fig. 584 ), 24. –25. IV.2015, 1♂ ( Figures 138–139 , 142, 144 , 146–149 , 223 , 239 , 243 , 405 , 558–560) 1juv., FKCP, leg. Kovařík et al.; Northern Province , Mannar District , Marichchukkaddi env, border of Wilpattu National Park, 08°33'32.3"N 079°56'51"E, 7 m a.s.l. (Locality 15CI, Fig. 585 ), 25. –26. IV.2015, 1♀, FKCP, leg. Kovařík et al.; North Central Province , Anuradhapura District , Mihintale, 08°20'51.8"N 080°30' 27.7"E, 156 m a.s.l. (Locality 15CL, Fig. 589 ), 27. – 28. IV.2015, 1♂, FKCP, leg. Kovařík et al.; North Central Province , Puttalam District , Eluwankulam, 08°17' 15"N 079°50'38.7"E, 38 m a.s.l. (Locality 15CO, Fig. 592 ), 28. IV.2015, 1♂ 1♀ ( Figures 140–141 , 143, 145 , 197 , 224 , 240–241, 244, 253 , 406 ) 1juv., FKCP, leg. Kovařík et al.; North Central Province , Sigiriya, 7°58'25.6"N 80°44'59.7"E, 1♀, UPSL, leg. S. Jayarathne.

DIAGNOSIS. Total length 30–50 mm. Manus of pedipalp very thin, width in male equal to that that of patella and femur. Pedipalps and legs yellow, with spots. Fingers and manus of pedipalps of the same color, spotted. Mesosomal segments light-colored. First (basal) middle lamella of both sexes pecten rounded. Posterior margin of sternite V strongly convex medially. Subaculear tooth spinoid. Pectinal teeth number 13–16.

HEMISPERMATOPHORE ( Figs. 146–149 ). Trunk broad, short, only slightly longer than capsule region. Capsule region broad. Flagellum laminiform, short, basally broadened and fused with median lobe. Median lobe rather narrow, distally truncate, with strong, curved dorsal carina. Basal lobe well developed, a broad hook-like process arising dorsally at base of median lobe.

DISTRIBUTION. Sri Lanka.

Figures

Figures 12–15: Maps showing the known geographical distribution of the Sri Lankan species.

Figures 138–141: Isometrus thwaitesi. Figures 138–139. Male from locality 15CH in dorsal (138) and ventral (139) views. Figures 140–141. Female from locality 15CO in dorsal (140) and ventral (141) views.

Figures 142–145: Isometrus thwaitesi. Figures 142, 144. Male from locality 15CH, chelicerae, carapace and tergites I–III (142) and sternopectinal region and sternite III (144). Figures 143, 145. Female from locality 15CO, chelicerae, carapace and tergites I–III (143) and sternopectinal region and sternite III (145).

Figures 146–149: Left hemispermatophore of Isometrus thwaitesi from locality 15CH. External (146), dorsal (147), internal (148) and ventral (149) views. Note: distal part of flagellum and basal part of trunk (foot) were damaged during dissection. Scale bar: 500 µm. Abbreviations: bl, basal lobe; f, flagellum; ml, median lobe; mlc, median lobe carina; pr, pars recta of flagellum; prf, pars reflecta of flagellum; t, trunk.

Figures 150–151: Isometrus thwaitesi from locality 15CF, male (150) and female (151).

Figures 193–200: Distal segments of leg IV, retroventral view of Sri Lankan Buthidae and Chaerilidae genera. Buthoscorpio sarasinorum, male from locality 15CF (193), Charmus laneus, male from locality 15CO (194), Hottentotta tamulus, male from locality 15CK (195), Isometrus maculatus, female from locality 15CI (196), Isometrus thwaitesi, female from locality 15CO (197), Lychas srilankensis, male from locality 15CJ (198), Reddyanus basilicus, male from locality 15CS (199), and Chaerilus ceylonensis, male from locality 15CD (200).

Figures 209–224: Metasomal segments II–III, lateral view of Sri Lankan Reddyanus and Isometrus species. Figures 209–210. Reddyanus basilicus, male (209) and female (210) from locality 15CR. Figures 211–212. R. besucheti, male holotype (211) and female from locality 15CG (212). Figures 213–214. R. ceylonensis sp. n., male holotype (213) and female paratype from locality 15CI (214). Figures 215–216. R. jayarathnei sp. n., male (215) and female (216) paratypes. Figures 217–218. R. loebli, male (217) and female (218) from locality 15CG. Figures 219–220. R. ranawanai sp. n., male holotype (219) and female paratype (220). Figures 221–222. Isometrus maculatus, male from locality 15CP (221) and female from locality 15CI (222). Figures 223– 224. I. thwaitesi, male from locality 15CH (223) and female from locality 15CO (224).

Figures 225–240: Pedipalp, dorsal view of Sri Lankan Reddyanus and Isometrus species. Figures 225–226. Reddyanus basilicus, male (225) and female (226) from locality 15CR. Figures 227–228. R. besucheti, male from locality 15CD (227) and female from locality 15CG (228). Figures 229–230. R. ceylonensis sp. n., male holotype (229) and female paratype from locality 15CI (230). Figures 231–232. R. jayarathnei sp. n., male (231) and female (232) paratypes. Figures 233–234. R. loebli, male (233) and female (234) from locality 15CG. Figures 235–236. R. ranawanai sp. n., male holotype (235) and female paratype (236). Figures 237–238. Isometrus maculatus, male from locality 15CP (237) and female from locality 15CI (238). Figures 239–240. I. thwaitesi, male from locality 15CH (239) and female from locality 15CO (240).

Figures 241–259: Pedipalp chela dorsal (241), movable finger (242–250), and fixed finger (251–259) of Sri Lankan Isometrus, Lychas, and Reddyanus species. Figures 241–242, 252. Isometrus maculatus, female from locality 15CO (241) and male from locality 15CP (242, 252). Figures 243–244, 253. I. thwaitesi, male from locality 15CH (243) and female from locality 15CO (244, 253). Figures 245, 254. Reddyanus basilicus, male from locality 15CS. Figures 246, 255. R. besucheti, male from locality 15CD. Figures 247, 256. R. ceylonensis sp. n., male holotype. Figures 248, 257. R. jayarathnei sp. n., male paratype. Figures 249, 258. R. loebli, male from locality 15CG. Figures 250, 259. R. ranawanai sp. n., male holotype. Figure 251. Lychas srilankensis, male from locality 15CO.

Figures 403–429: Telson, lateral view of Sri Lankan Buthidae and Chaerilidae species. Figures 403–404. Isometrus maculatus, male from locality 15CP (403) and female from locality 15CI (404). Figures 405–406. I. thwaitesi, male from locality 15CH (405) and female from locality 15CO (406). Figures 407–408. Lychas srilankensis, male (407) and female (408) from locality 15CJ. Figures 409–410. Reddyanus basilicus, male (409) and female (410) from locality 15CR. Figures 411–412. R. besucheti, male holotype (411) and female from locality 15CG (412). Figures 413–414. R. ceylonensis sp. n., male holotype (413) and female paratype (414) from locality 15CI. Figures 415–416. R. jayarathnei sp. n., male (415) and female (416) paratypes. Figures 417–418. R. loebli, male (417) and female (418) from locality 15CG. Figures 419–420. R. ranawanai sp. n., male holotype (419) and female paratype (420). Figures 421–422: Buthoscorpio sarasinorum, male from locality 15CF (421) and female from locality 15CG (422). Figures 423–424. Charmus laneus, male (423) and female (424) from locality 15CO. Figures 425–426. Charmus saradieli sp. n. male paratype (425) (MHNG) and female holotype (426). Figurs 427. Hottentotta tamulus, male from locality 15CK (427). Figures 428–429. Chaerilus ceylonensis, male (428) and female (429) from locality 15CD.

Figures 579–581: Figures 579–580. Locality 15CE, Sri Lanka, North Central Province, Polonnaruwa District, Giritale, 08°01'26.0"N 080°54'37.2"E, 233 m a.s.l. During night collecting on 22.–23.IV.2015 in the hotel garden (UV detection) we recorded Heterometrus swammerdami (inside the termite constructions, Fig. 580) and Heterometrus gravimanus inside burrows in open terrain. The mothers had 30 to 60 cm long oblique burrows usually once curved from which several narrow burrows created by their juveniles separated under surface. Every burrow of juveniles has a proper exit 15 to 90 cm from the main exit of the motherś burrow. On the locality we recorded night temperature 32.8 ºC– 26.5 ºC (minimum temperature) and night humidity varied between 51% and 79%. Figure 581. Locality 15CF, Sri Lanka, North Central Province, Polonnaruwa District, near Kaudulla National Park, 08°08'40.6"N 080°51'04"E, 101 m a.s.l. During a day 23.IV.2015 we recorded Buthoscorpio sarasinorum (under stones or woods), Isometrus thwaitesi (under dry bark of standing trees), Reddyanus besucheti (under stones), and Chaerilus ceylonensis (under stones).

Figures 547–554: The mitotic metaphases of buthid males from Sri Lanka. Buthoscorpio sarasinorum from locality 15CF (2n=14) (547), Charmus laneus from locality 15CO (2n=9) (548), Isometrus thwaitesi from locality 15CF (2n=8) (549), Lychas srilankensis from locality 15CN (2n=16) (550), Reddyanus basilicus from locality 15CS (2n=16) (551), Reddyanus basilicus from locality 15CR (2n=15) (552), Reddyanus ceylonensis from locality 15CI (2n=16) (553), Reddyanus loebli from locality 15CH (2n=17) (554). Arrowheads indicate extra large odd chromosomes. Scale bar = 5 µm for 547–554.

Figures 582–584: Figures 582–583. Locality 15CG, Sri Lanka, Central Province, Matale District, Habarana, Wananiwahana Resort, 07°59'25.8"N 080°43'24.6"E, 280 m a.s.l. During night collecting on 23.–24.IV.2015 in Wananiwahana resort garden (UV detection) we recorded Buthoscorpio sarasinorum (running on the land among leaves), Reddyanus besucheti (on the land among leaves) and Reddyanus loebli (hidden under scales of barks of standing tree trunks, see the blue arrows on the Fig. 583). On the locality we recorded night temperature 28.4 ºC– 24 ºC (minimum temperature) and night humidity varied between 55% and 87%. Figure 584. Locality 15CH, Sri Lanka, Northern Province, Mannar District, Madhu Road, 08°48'26.3"N 080°10'26"E, 90 m a.s.l. During night collecting on 24.–25.IV.2015 (UV detection) we recorded Isometrus maculatus and Isometrus thwaitesii sympatrically (running on branches and trunks of trees, also siting on leaves one to four metres high), Reddyanus ceylonensis sp. n. (on the land among leaves), Reddyanus loebli (hidden under scales of barks of standing tree trunks).

Figures 585–587: Figure 585. Locality 15CI, Sri Lanka, Northern Province, Mannar District, Marichchukkaddi env, border of Wilpattu National Park, 08°33'32.3"N 079°56'51"E, 7 m a.s.l. During night collecting on 25.–26.IV.2015 (UV detection) we recorded Isometrus maculatus and Isometrus thwaitesii sympatrically (running on branches and trunks of trees, also sitting on leaves one to four metres high), Reddyanus ceylonensis sp. n. (on the land among leaves; the type locality), Reddyanus loebli (hidden under scales of bark of standing tree trunks). Near to the locality we recorded temperature between 37.6 ºC (maximum daytime temperature and 26.2 ºC (minimum nighttime temperature) shortly before sunrise. Humidity varied between 67% and 81%. Figures 586–587. Locality 15CJ, Sri Lanka, Northern Province, Jaffna District, 09°42'51.6"N 080°04'44.8"E, 19 m a.s.l. During night collecting on 26.–27.IV.2015 (UV detection) we recorded Lychas srilankensis (on the land usually under branches, leaves or in their vicinity), Heterometrus swammerdami (inside the termite constructions or inside heaps of garden "waste") and Heterometrus gravimanus inside burrows in open terrain (Fig. 587). The females had 30 to 60 cm long oblique burrows once or twice curved. A female shortly after maturity ecdysis was in the burrow together with a male; another female was in the burrow together with three juveniles which had their own narrow burrows separated under surface from the motherś burrow; a juvenile after the third ecdysis had a proper burrow 30 cm long oblique and once curved. There also lives Isometrus maculatus. On the locality we recorded night temperature 31.6 ºC– 27.2 ºC (minimum temperature) and night humidity varied between 60% and 87%.

Figures 588–589: Figure 588. Locality 15CK, Sri Lanka, Northern Province, Jaffna District, 09°49'15.4"N 080°08'41.6"E, 19 m a.s.l. During day 27.IV.2015 we recorded Hottentotta tamulus under stones or woods and also in vicinity of houses. Figure 589. Locality 15CL, Sri Lanka, North Central Province, Anuradhapura District, Mihintale, 08°20'51.8"N 080°30'27.7"E, 156 m a.s.l. During night collecting on 27.–28.IV.2015 (UV detection) we recorded Isometrus thwaitesii (running on branches and trunks of trees, also sitting on leaves), Reddyanus besucheti (on the ground among leaves), Reddyanus loebli (hidden under scales of bark of standing tree trunks) and Heterometrus swammerdami (inside burrows). On the locality we recorded night temperature 27.4 ºC– 24.5 ºC (minimum temperature) and night humidity varied between 64% and 87%.

Figures 592–594: Figure 592. Locality 15CO, Sri Lanka, North Central Province, Puttalam District, Eluwankulam, 08°17'15"N 079°50'38.7"E, 38 m a.s.l. During night collecting from 10.30 p.m. on 28.IV.2015 to 4.00 a.m. on 29.IV.2015 (UV detection) we recorded Charmus laneus (running on the ground among leaves), Isometrus thwaitesii (running on branches of bushes, also sitting on leaves), Lychas srilankensis (on the ground under branches, leaves or in their vicinity), Reddyanus ceylonensis sp. n. (on the ground), Chaerilus ceylonensis (inside oblique usually not curved burrows 15 to 30 cm long) and Heterometrus swammerdami (inside long burrows). On the locality we recorded between 10.00 p.m. and 4.00 a.m. temperature 25.9 ºC and humidity between 58% and 70%. On the locality we recorded 6 scorpion species and genera of all three Sri Lankan families. Figures 593–594. Locality 15CP, Sri Lanka, Southern Province, Matara District, Kekanadura village, 05°58'28.2"N 080°36'20.5"E, 40 m a.s.l. During night collecting on 30.IV.2015 (UV detection) we recorded Isometrus maculatus (inside a house, the species occupy the roof of the house, Fig. 593) and Heterometrus serratus (inside almost straight burrows in a ground wall). On the locality we recorded night temperature 28.4 ºC– 25.2 ºC (minimum temperature) and night humidity varied between 63% and 89%.