Isometrus Ehrenberg, 1828

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 : 31-33

publication ID	https://doi.org/10.18590/euscorpius.2016.vol2016.iss220.1
DOI	https://doi.org/10.5281/zenodo.7124501
persistent identifier	https://treatment.plazi.org/id/B07187DF-A837-FFB2-FC1C-F9599AFCF8CC
treatment provided by	Felipe (2021-11-30 05:11:22, last updated 2024-11-26 04:41:19)
scientific name	Isometrus Ehrenberg, 1828
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Isometrus Ehrenberg, 1828 View in CoL

( Figs. 13 View Figures 12–15 , 127–151 View Figures 127–130 View Figures 131–134 View Figures 135–137 View Figures 138–141 View Figures 142–145 View Figures 146–149 View Figures 150–151 , 196–197 View Figures 193–200 , 221–224 View Figures 209–224 , 237–244, 252– 253 View Figures 225–240 View Figures 241–259 , 403–406 View Figures 403–429 , 549– 555 View Figures 547–554 , 557– 560 View Figures 555–570 )

Buthus (Isometrus) Ehrenberg in Hemprich & Ehrenberg, 1828: pl. 1, fig. 3; Hemprich & Ehrenberg, 1829: 351.

Isometrus (Isometrus) : Vachon, 1972: 169–180, figs. 1– 13, 15, 17, 19; Vachon, 1982: 86–90, 100–101, 108, figs. 28–39, 64–65; Fet & Lowe, 2000: 146–150 (complete reference list until 1998); Kovařík, 2003: 2; Kovařík & Ojanguren, 2013: 182–184, 347, 353, 355–357, figs. 1251–1264, 1354–1357, 1368–1375, 1376–1385.

Isometrus View in CoL ( Raddyanus [sic]): Tikader & Bastawade, 1983: 254–311 (in part), figs. 771–840.

= Isometrus (Closotrichus) Tikader & Bastawade, 1983: 311–316 , figs. 896–910 (syn. by Kovařík, 1994: 201).

TYPE SPECIES. Scorpio maculatus De Geer, 1778 .

DIAGNOSIS. Medium sized buthids, adults 30–75 mm. Sternum type 1, triangular in shape. Pedipalps orthobothriotaxic, type Aβ. Chelal trichobothrium db located between dt and et. Three to five pairs of lateral eyes. Tibial spurs absent on all legs. Movable and fixed fingers of pedipalps with six rows of granules, several accessory granules and external and internal granules. Cheliceral fixed finger with a single ventral denticle. Third and fourth legs with tibial spurs. Tibia and tarsomeres of legs I–III with setae not arranged into bristle combs on dorsal surfaces. Tarsomeres II of leg IV with two rows of more than 30 dense setae. Mesosoma dorsally with one median carina. Telson with subaculear tooth pointed (except for Isometrus formosus Pocock, 1894 ). Pedipalp and metasomal segments longer in males than females.

COMMENTS. The taxonomic position of Isometrus formosus Pocock, 1894 from Indonesia is unclear. This species is probably not a member of the genus Isometrus , but comprises a separate genus. Two species of Isometrus , I. maculatus ( De Geer, 1778) and I. thwaitesi Pocock, 1897 are known from Sri Lanka. Pocock, 1900: 48, in remarks on the Indian species I. thurstoni Pocock, 1893 , wrote: "There are also two specimens in the British Museum labelled Ceylon ". However, as no other specimen of I. thurstoni has ever been recorded from Sri Lanka, we believe that I. thurstoni probably does not occur there.

DISTRIBUTION. Oriental region from India to Melanesia (see comments for I. maculatus ).

References

GEER, C. DE. 1778. Memoires pour servir a l`histoire des Insectes (tomus 1 - 7. 1752 - 1778). Stockholm: Pierre Hesselberg, 456 pp.

FET, V., W. D. SISSOM, G. LOWE & M. E. BRAUNWALDER. 2000. Catalog of the Scorpions of the World (1758 - 1998). New York: The New York Entomological Society, 689 pp.

HEMPRICH, F. W. & C. G. EHRENBERG. 1828. Zoologica II. Arachnoidea. In: Symbolae Physicae seu Icones et Descriptiones Animalium Evertebratorum Sepositis Insectis quae ex Itinere per Africam Borealem et Asiam Occidentalem. Friderici Guilelmi Hemprich et Christiani Godofredi Ehrenberg, Medicinae et Chirurgiae Doctorum, Studio Novae aut Illustratae Redierunt. Percensuit et Regis Iussu et Impensis Edidit Dr. C. G. Ehrenberg. Decas Prima. Berolini ex Officina Academica, Venditur a Mittlero: plate I Buthus; plate II: Androctonus.

HEMPRICH, F. W. & C. G. EHRENBERG. 1829. Vorlaufige Uebersicht der in Nord-Afrika und West- Asien einheimischen Skorpione und deren geographischen Verbreitung. Verhandungen der Gesellschaft der Naturforschender Freunde in Berlin, 1 (6): 348 - 362.

KOVARIK, F. 1994. Isometrus zideki sp. n. from Malaysia and Indonesia, and a taxonomic position of Isometrus formosus, I. thurstoni and I. sankariensis (Arachnida: Scorpionida: Buthidae). Acta Societatis Zoologicae Bohemicae, 58: 195 - 203.

KOVARIK, F. 2003. A review of the genus Isometrus Ehrenberg, 1828 (Scorpiones: Buthidae) with descriptions of four new species from Asia and Australia. Euscorpius, 10: 1 - 19.

KOVARIK, F & A. A. OJANGUREN AFFILASTRO. 2013. Illustrated catalog of scorpions Part II. Bothriuridae; Chaerilidae; Buthidae I., genera Compsobuthus, Hottentotta, Isometrus, Lychas, and Sassanidotus. Clairon Production, Prague, 400 pp.

POCOCK, R. I. 1894. A small contribution to our knowledge of the scorpions of India. Annals and Magazine of Natural History, 6 (13): 72 - 84.

POCOCK, R. I. 1897. Descriptions of some new species of scorpions from India. Journal of the Bombay Natural History Society, 11: 102 - 117.

POCOCK, R. I. 1900. Arachnida. The fauna of British India, including Ceylon and Burma. Published un- der the authority of the Secretary of State for India in Council. London: W. T. Blandford, xii, 279 pp

TIKADER B. K. & D. B. BASTAWADE. 1983. The Fauna of India: Scorpions. Scorpionida, Arachnida. Vol III. Zoological Survey of India, Calcutta, 668 pp.

VACHON, M. 1972. Remarques sur les scorpions appartenant au genre Isometrus H. et E. (Buthidae) a propos de l`espece Isometrus maculatus (Geer) habitant Ile de Paques. Cahiers Pacifique, 16: 169 - 180.

VACHON, M. 1982. Les scorpions de Sri Lanka (Recherches sur les scorpions appartenant ou deposes au Museum d`Histoire naturelle de Geneve III.). Revue suisse de Zoologie, 89: 77 - 114.

Figures

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

Figures 127–130: Isometrus maculatus. Figures 127–128. Male from locality 15CP in dorsal (127) and ventral (128) views. Figures 129–130. Female from locality 15CI in dorsal (129) and ventral (130) views.

Figures 131–134: Isometrus maculatus. Figures 131, 133. Male from locality 15CP, chelicerae, carapace and tergites I–III (131) and sternopectinal region and sternite III (133). Figures 132, 134. Female from locality 15CI, chelicerae, carapace and tergites I–III (132) and sternopectinal region and sternite III (134).

Figures 135–137: Isometrus maculatus, female from locality 15CH (135) with newborns before first ecdysis (136), and with juveniles after first ecdysis (137).

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 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 555–570: Key characters for distinguishing males of Sri Lankan Isometrus and Reddyanus. Figures 555–556, 565– 566. Pedipalp chela dorsal view, I. maculatus from locality 15CP (555), I. thwaitesi from locality 15CH (556), R. basilicus, holotype (565), and R. besucheti, holotype (566). Figures 557–558. Sternopectinal area, I. maculatus from locality 15CP (557), and I. thwaitesi from locality 15CH (558). Figures 559–560, 567–570. Sternite V, I. maculatus from locality 15CP (559), I. thwaitesi from locality 15CH (560), R. besucheti, from locality 15CF (567), R. ceylonensis sp. n., holotype (568), R. jayarathnei sp. n., paratype (569), and R. ranawanai sp. n., paratype (570). Figures 561–564. Metasomal segment II lateral (561–562) and pedipalp patella dorsal (563–564), R. loebli from locality 15CG (561, 563) and R. besucheti, from locality 15CF (562, 564).