A NEW SPECIES AND A KEY TO SPECIES OF POLYRHACHIS SMITH (HYMENOPTERA: FORMICIDAE) FROM INDIA Author Karmaly, K. A. A NEW SPECIES AND A KEY TO SPECIES OF POLYRHACHIS SMITH (HYMENOPTERA: FORMICIDAE) FROM INDIA K.A. KARMALY ABSTRACT A new species of Polyrhachis Smith, Viz P.narendrani sp nov from Kerala is described and illustrated. The affinities of this species with its closest relatives are discussed and a key to Indian species is also provided. Key words: Formicidae, Polyrhachis narendrani, new species, India. INTRODUCTION The genus Polyrhachis comes under the subfamily Formicinae. It is found to be the third largest group in the subfamily with 477 species all over the world. [BOLTON 1995]. So far 48 species and 13 sub species has been reported from India and 13 species and 10 subspecies from Kerala. This genus was erected by Smith (1857) based on the type species Formica bihamata. Gerstaecker (1858) erected another genus Hopolomyrmus with the type species Hopolo schistanceus.Later Mayr ( 1863) synoymised this series with Polyrhachis. Now there are 14 subgenera in Polyrhachis including the nominal genus. In this paper, A new species is described from Kerala and a key to species is provided. The new species is named in honour of Prof. T.C Narendran for his significant contribution to the study of Taxonomy of Oriental Insects. The holotype is deposited in the DZCU for the time being, but eventually will be transferred to the ZSIC. MATERIALS AND METHODS Ants were mostly collected by hand picking with fine zero point brush and with help of aspirator. They were also collected by sweeping method. Specimens were preserved in 70% alcohol in plastic vials. Observations were made in field where ants were found making nests on the twigs, soil surface and foliages. ABBREVIATIONS : F - Funicular segments ; W - Worker ; TL - Total length - Toal length of specimen from apex of mandible to apex of gaster ; HL- Head length - Length of head proper excluding mandibles ; HW - Head width - Maximum width of head in full face view ; CI - Cephalic index ie. (HW x 100)/HL ; SL - Scape length ; SI - Scape Index ie. (SL x 100)/HW ; ED - Eye diameter ; PW -Pronotal width - Maximum width of pronotum in dorsal view ; F1 -F11 - Funicular segments ; AL - Alitrunk length ; DZCU -Department of Zoology, Calicut University; ZSIC - Zoological survey of India, Calicut. RESULTS AND DISCUSSION Polyrhachis (Myrma) narendrani sp. nov. (Figs. 1-2) Worker. TL = 6.2 mm; HL = 1.8 mm; HW = 1.4 mm; CI = 77 mm; SL = 1.6 mm; SI = 114.28 mm; ED = 0.2 mm; PW = 2.4 mm; AL = 2.2 mm. Colour. Head, thorax, node of pedicel, gaster black; legs more or less castaneous red; silky silvery hairs; pubescence white; tibial spines reddish yellow; tarsal spur reddish brown. Sculpture and Hair pattern: Head, thorax and abdomen shining; head and thorax minutely regulose; abdomen more minutely regulose than head and thorax; pubescence adpressed, sparse on body, dense on antennae and on thorax laterally; silky silvery erect hairs scattered on head, thorax and gaster, more abundant on apex of gaster underneath. Head: Very convex in front and at the sides, tending to be more convergent in front of the eyes, rounded posteriorly; mandibles sublinear, 5-toothed; clypeus carinate, tectiform, its anterior margin arcuate with a shallow median lobe; frontal lobes small, subparallel; frontal carinae prominent; parallel; antennal carinae distinct; scrobe indistinct, torulus rounded, horizontal; antennal insertion separated from posterior clypeal margin by a distinct gap, antennae short, slender, 12 jointed; antennal scape extending little beyond the top of head; all segments of funiculus longer than broad, 1st funicular segment longer than remaining segments, last segment thickened and club shaped. Relative measurements of length of antennal segments: Scape = 1.6 mm; F1 = 0.9 mm; F2 = 0.35 mm; F3 = 0.2 mm; F4 = 0.2 mm; F5 = 0.2 mm; F6 = 0.2 mm; F7 = 0.2 mm; F8 = 0.15 mm; F9, = 0.2 mm; F10 = 0.2 mm; Club (F11) = 0.3 mm; Eyes moderately large placed, more towards the posterior end, slightly above the lateral sides. Thorax. More or less flat above; sides margined along their whole length; pronotum broad posteriorly, narrower anteriorly, two strong long erect spines on anterolateral angles of pronotum, pointing forwards; pro-mesonotal suture very distinct; meso-metanotal impressions present, but no distinct suture; metanotal groove indistinct; metanotum unarmed; propodeum anteriorly margined and anterior corners projecting upwards, thorax deeply emarginate at pro-meso and meso-metanotal stutures; propodeum situated at a level below the pro-mesonotum, emarginate, the dorsum very oblique and sloping into the vertical and weakly concave declivity, ends with a carina; legs slender, elongate; tibiae cylindrical with a spine beneath; tarsi with tarsal spurs. Abdomen: In front view the sides of petiole diverge from the base, pass through the rounded angle and then converge dorsally to the base of a pair of curved spines; petiolar node rhomboidal, biconvex slightly arched at middle, bearing two long spines on dorsolateral edges guarded by two small teeth on sides; long spines slightly curved backwards at their tips. Gaster globose, with four visible segments, first gastral segment larger, covering more than half of its length, apex of last gastral segment with circular anal orifice guarded by guard hairs. Holotype: Worker. INDIA: Kerala, Thiruvananthapuram -Palode, Karmaly. K.A., 10.iii-2000. [DZCU]. Etymology. Named in honour of Prof. T. C. Narendran. Distribution : INDIA : [Kerala: Thiruvananthapuram]. Bioogy. Unknown. Habitat. Disturbed with small plants and trees. Discussion: This new species resembles Polyrhachis convexa Roger in the following features: 1. Antennae 12 jointed; 2 Clypeus tectiform; 3. Thorax flat above, sides margined along their whole length. However this new species differs from Polyrhachis convexa Roger in having: 1. Pronotal spine long (in Polyrhachis convexa pronotal spine short); 2. Legs with spines and erect hairs (in Polyrhachis convexa legs devoid of spines and erect hairs); 3. Petiolar node rhomboidal, biconvex with two long spines on dorsolateral edges guarded by two small teeth on sides (in Polyrhachis convexa petiolar node broad, biconvex with four short subequal spines, equidistant from each other). POLYRHACHIS F. SMITH KEY TO INDIAN SPECIES OF POLYRHACHIS F. SMITH [Based on Workers] 1. Thorax armed with spines or teeth [Fig.3]................................2 Thorax unarmed [Fig. 4].........................................................60 2. Thorax rounded above, sides not margined along their whole length................................................................................3 Thorax flat above, sides margined along their whole length ...................................................................................37 3. Mesonorum armed with spines............................................. 4 Mesonotum unarmed............................................................ 6 4. Petiole spines parallel, not divergent from base [Fig.5] ....................................................................................................5 - Petiole spines not parallel, but divergent from base [Fig.6] .... .....................................................................P. ypsilon Emery. 5. Pronotal spines pointing outwards and curved laterally backwards, forming hooks [Fig.7]............ P. bihamata [Drury] Pronotal spines pointing outwards and downwards, not curved, not forming hooks [Fig.8]................P. bellicosa Smith Metanotum armed with spines [Fig.9]....................................7 Metanotum unarmed [Fig.10]...............................................33 7. Pubescence soft erect and abundant.......................................8 - Pubescence silky, short and recumbent, or sparse and erect, or entirely wanting.................................................................10 8. Spines on petiole forming hooks [Fig.11] [Kerala] .............................................................................P. furca ta Smith Spines on petiole not forming hooks [Fig.12]...........................9 9. Head smooth, shining, not punctured..................................... ..................................P. graciliori Forel [= weberi Donisthorpe] Head not smooth, not shining, but coarsely punctured........... ..........................................P. rufipes F.Smith [= phipsoni Forel] 10. Spines on metanotum forming hooks [Fig.13]........................11 - Spines on metanotum not forming hooks [Fig.14] ........................................................................................................13 11. Abdomen clothed with golden hairs...........P. rupicapra Roger Abdomen not clothed with hairs.............................................12 12. Head and abdomen opaque; thorax finely punctured .............................................................................P. hodgsoni Forel Head and abdomen not opaque, shining; thorax coarsely punctured.........................................................P. arachne Emery 13. Basal portion of metanotum without margin laterally ......................................................................................................14 Basal portion of metanotum with margin laterally.............27 14. Pubescence sparse or entirely wanting................................15 Pubescence dense, silky and recumbent.................................23 15. Spines on petiole wide-spread encircling front of abdomen .......................................................................................................16 Spines on petiole not wide-spread, and not encircling abdomen .......................................................................................................18 16. Head with a tubercle on either side behind the eyes ............... ...............................................................P. tubericeps Forel Head without a tubercle on either side behind the eyes.....17 17. Propodeal spines slightly curved [Kerala]................................. .........................................................P. lacteipennis Smith [in part] Propodeal spines not curved...................P. thompsoni Bingham 18. Head, thorax and abdomen shining; metallic blue or purple .....................................................................P. venus Forel - Head, thorax and abdomen not shining, black; abdomen sometimes red..................................................................19 19. Head, thorax and petiole node coarsely punctured.............20 Head, thorax and petiole node finely punctured...................21 20. Abdomen black; petiole node cubical.......P. arrnata Le Guillou - Abdomen ferruginous; petiole node arcuate with acute spines ................................................................................P. fortis Emery 21. Petiolar node with two median vertical short acute spines between spines on upper lateral angles of node [Fig.15] ...................................................................P. hauxwelli Bingham Petiolar node without median spines between spines on upper lateral angles of node [Fig. 16]..................................................22 22. Metanotal spines erect, slightly bent outwards [Kerala] ...............................P. lacteipennis F. Smith .[= simplex Mayr] Metanotal spines not erect, strongly curved inwards .............................................................................P. m en elas Forel 23. Abdomen red......................................................P. bicolor Smith Abdomen black.......................................................................24 24. Pubescence golden or bronzy yellow...................................25 Pubescence silvery [Kerala]....................P. tibialis tibialis Smith 25. Two small teeth between spines on upper lateral angles of petiolar node.............................................................................26 - Three small teeth between spines on upper lateral angles of petiolar node........................................................P. vicina Smith 26. Head short and broad................................P. dives dives Smith - Head long and broad...................................P. dives belli Forel 27. Spines on pronotum and metanotum subequal.....................28 Spines on pronotum and metanotum not subequal.............30 28. Petiolar node longer than wide..............................................29 Petiolar node not longer than wide, but cubical............................ ..............................................................................P. chalybea Smith 29. Abdomen red; length 7 mm - 9 mm..................P. .hector Smith [= abdominalis Smith = mutatus Smith = mutata Smith, r. ajax Forel] - Abdomen bronze green; length 6 mm - 7 mm............................ .................................................................................P. aedipusForel 30. Pronotal spines short, stout and straight [Kerala].................. .............................................................................P. binghamiiVorel - Pronotal spines long, acute, pointing divergent or straightly pointing forwards...........................................................31 31. Basal portion of metanotum posteriorly transversely margined .........................................................................P. pubescensMayr Basal portion of metanotum posteriorly bunded by a faint transverse carina........................................................................32 32. Thorax strongly arched...................P. aculeata aculeata Mayr Thorax more gibbous............................P. aculeata gibbosa Forel 33. Metanotum with spines [Fig.9].............................................35 Metanotum without spines [Fig. 7].........................................34 34. Abdomen, legs reddish yellow; antennae and front of head reddish..........................................P. laevissima dichroa Forel - Abdomen, antennae and front of head black; legs blood red ................................................P. laevissima laevissima Smith 35. Abdomen very convex above, not depressed......................36 - Abdomen slightly convex above, strongly depressed............ .........................................................................P. wroughtoni Forel 36. Abdomen red, smooth and shining...............P. laevigata Smith - Abdomen black, feebly reticulate, punctate and slightly shining ..............................................P. hippomanes ceylonensis Emery 37. Pronotum, mesonotum and metanotum with spines ........................................................................P. craddocki Bingham Pronotum with spine, mesonotum and metanotum with or without spines, teeth or tubercles...........................................38 38. Pronotum always with a spine; mesonotum and metanotum with triangular lamina........................................P. horni Emery - Pronotum with or without spines; mesonotum unarmed; metanotum with teeth or lamina or spine or tubercle ...................................................................................................39 39. Pronotum with long or short spine.......................................40 Pronotum without spine.........................................................57 40. Pronotum with long spines [Fig.17]........................................41 - Pronotum with short spines or teeth [Fig.9]...........................51 41. Petiole node with two long spines on upper angles, and two short lateral spines or teeth...................................................42 - Petiole node with four short sub equal spines.......................49 42. Lateral spines or teeth truncate or bimucronate at apex.... 43 Lateral spines or teeth pointed, not truncate nor bimucronate at apex......................................................................................44 43. Very dense pubescence on body hiding the sculpture............ ......................................................P. proxima proxima Roger - Very sparse pubescence on body not hiding the sculpure .......................................................P. illaudata intermedia Forel. 44. Pubescence on body very dense [Kerala]..................................... ............P. illaudata illaudata Walker [= P. mayri mayri Roger] - Pubescence on body very sparse or wanting......................45 45. Basal portion of metanotum convex ..................... ...........................................................P. hemiopticoides Mukerjee Basal portion of metanotum not convex, but transversely submargined................................................................................46 46. Antennal carinae long, divergent posteriorly.......................47 Antennal carinae short, not divergent posteriorly..............48 47. Abdomen finely punctured and the punctures seem to run into tninutely fine striae.....................................P. striata sfriafa Mayr Abdomen simply recticulate punctuate, without the trace of striae....................................................P. striata assamensis Forel 48. Meso-metanotal suture very distinct; legs densely covered with long erect hairs.............P. sumatrensis hamulata Emery Meso-metanotal suture not very distinct; legs not covered with long erect hairs, smooth................................P.yerburyi Forel 49. Pubescence, recumbent and yellowish, length 9 mm - 10 mm........................................................P. striatorugossa Mayr Pubescence, recumbent and glistening greyish, length 5 mm -6 mm............................................................................................50 50. Pronotal spine short................................P. convexa Roger Pronotal spine long......................P. narendrani sp. nov. 51. Petiole node with two long spines on upper lateral angles and two short obtuse teeth between them................P. jerdoniFbrel - Petiole node with three or four spines or teeth.....................52 52. Petiole node quadridentate or quadrispinous.......................53 Petiole node trispinous...........................................................55 53. Clypeus carinate........................................................................54 Clypeus not carinate [Kerala] .......................................... .........................................................P. punctillata fergusoni Forel 54. Clypeus medially carinate [Kerala]............................................. ....................................................P. punctillata punctillataRoger - Clypeus posteriorly carinate ................................. .................................................P. punctillata smythiesi Forel 55. Antennal carinae divergent posteriorly.................................56 - Antennal carinae not divergent posteriorly........................... ..........................................................................P. frauenfeldiMayr 56. Node of pedicel longer than wide [Kerala] .......................... ..............................................................P. thrinax thrinax Roger - Node of pedicel as long as wide ............................................ ..................................................P. thrimax var. lancearius Forel 57. Metanotal spines vertical, very small [Fig.20] [Kerala] ............................................................................P. halidayi Emery Metanotal spines broad, triangular, pointing backwards [Fig.21]......................................................................................58 58. Head and thorax punctured, not striate.................................59 - Head and thorax not punctured, but striate [Kerala]............... ...............................................................P. exercita rastrata Emery 59. Petiolar node quadrispinous, equidistant from one another [Fig.90] [Kerala].........................P. exeriita exercita [Walker] [= P. clypeata clypeata Mayr] - Petiolar node quadrispinous, not equidistant from one another .................................................P. exercita obtusisquama Forel 60. Viewed from side thorax very convex, strongly arched and gibbous anteriorly.............P. rastellata rastellata [Latreille] - Viewed from side thorax nearly as convex, rounded anteriorly .......................................................P. rastellata pagana Santschi ACKNOWLEDGEMENTS The author is grateful to Dr. T.C.Narendran, Professor, Department of Zoology, University of Calicut for his benevolent help. She thanks UGC for financial assistance. For facilities, she thanks the authorities of University of Calicut. With great pleasure the help rendered by Dr. Rudolf J.Kohout, Queensland Museum, Australia is acknowledged. REFERENCES BINGHAM, C.T. 1903. Ants and Cuckoo wasps. The Fauna of British India, Including Ceylon and Burma: Hym. 2.1-506, London. BOLTON, B. 1973b. The ant genus Polyrhachis F. Smith in the Ethiopian region. Bull. Brit. Mus. (Nat. Hist.) (Entomology; 28: 283-369. BOLTON, 1974b. New synonymy and a new name in the ant genus Polyrhachis F. Smith. Ent. Month. Mag. 109:172-180. BOLTON, B. 1975c. The Sexspinosa - group of the ant genus Polyrhachis F. Smith. Jour. Ent. (Series B) 44:1-14. BOLTON, B.1994. Identification guide to the ant genera of the world: 222 pp. Cambridge, Mass. BOLTON, B. 1995b. A new general catalogue of the ants of the world, pp. 504. Cambridge, Mass. BROWN, W.L., Jr. 1959d. Variation in the ant Polyrhachis thrinax Ent. News 70:164. CHAPMAN, J.W. & CAPCO, S.R. 1951. Checklist of the ants of Asia. Monographs of the Institute of Science and Technology, Manila, 1: pp.327. DONISTHORPE, H. 1937c. A new subgenus and three new species of Polyrhachis Smith. Entomologis 70: 273-276. DONISTHORPE, H. 1938. Ants from the Colombo Museum Expedition to Southern India. Ann. Mag. Nat. Hist. (11) 10:196-208. DONISTHORPE, H. 1938c. The subgenus Cyrtomyrma Forel of Polyrhachis Smith, with descriptions of new species, etc. Ann. Mag. Nat. Hist. (11)1:246-267. DONISTHORPE, H. 1942b. Descriptions of a few ants from the Philippine Islands, and a male of Polyrhachis bihamata Drury from India. Ann. Mag. Nat. Hist. (11)9: 64-72. DONISTHORPE, H. 1944c. A new subgenus and three new species of Polyrhachis F. Smith. Ent. Mon. Mag. 80: 64-66. DORROW, W.H.O., MASCHWITZ, U. 1990. The arachne-group of Polyrhachis: Weaver ants cultivating Homoptera in Borneo. Insects sociaux 37: 73-89. EMERY, C. 1921e. Le genre Polyrhachis. Classification; species nouvelles on critiques. Bull. Soc. Vau. Sci. Nat. 54:17-25. FOREL, A. 1885a. Indian ants of the Indian Musseum, Calcutta. Jour. AS. Soc. Beng. part 2. Natural science 54:176-182. GERSTAECKER, C.E.A. (1858): Bericht uber die zur Bekanntmachung geeigneten Verhandlungen der Konigl. Preuss. Akademie der Wissenschaflen zu Berlin. Mber.K.Preuss. Akad.Wiss, April 1858:261-264. HUNG, A.C.F. 1967b. A revision of the ant genus Polyrhachis at the subgeneric level. Trans. Ameri, Ent. Soc. 93:395-422. HUNG, A.C.F. 1970. A revision of the ant subgenus PolyrhachisVr. Smith. Oriental Insects. 4:1-36. JERDON, T.C. 1854. A catalogue of the species of ants found in Southern India. Ann. Mag. Nat. Hist. (2), 13:45-56,100-110. KOHOUT, R.J. 1994. Polyrhachis lama, a new ant from the Tibetan plateau Mem. Quee. Mus. 35(1): 137-138. KOHOUT, R.J. 1998. New synonyms and nomenclatural change in the ant genus PolyrhachisVr. Smith. Mem. Quee. Mus42(2): 505-531. LATREILEE, P.A.(1802): Histoire Naturelle des Fourmis et recueil de memories et d'observations sur.les abeilles, les araignées, les faucheurs, et autres insects:445.pp.Paris MAYR,G.(1863): Formicidarum index synonymicus Verh. Zool. Bot. Ges.Wien 13: 385-460 SMITH, F.(1857): Catalogue of Hymenopterous insects collected at Sarawak, Mt Ophir and at Singapore by A.R.Wallace . J .Proc . Linn.Soc .Z:42-130 SMITH, F (1858) : Catalogue of Hymenopterous insects in the collection of the British museum - 6 Formicidae:216 pp.London WALKER,F (1859): Characters of some apparently undescribed Ceylon insects. Ann. Mag.Nat. Hist. (3) 4:370 - 376 Figs. 1 & 2 Polyrhachis narendrani sp.nov 1. Body Profile 2. Head - front view Figs. 3 & 4. Thorax 3. Polyrhachis thrinax thrinax Roger 4. P. rastellata raslellata (Latreille) 5 & 6. Petiole spine 5. P. bighamata Drury 6. P. ypsilon Emery 7 & 8. Pronotal spines 7. P. bighamata Drury 8. P. bellicose Smith 9&10. Metanotum 9. P. tibialis tibialis Smith 10. .P. hastellata hastellata (Latreille) 11 & 12. Petiolar spines 11.P. furcata Smith 12. P.punctillata punctillata Roger 13 & 14. Metanotal spines 13. P. archane Emery 14. P. venus Smith 15 & 16. Petiole 15. P. wroughtonii Forel 16. P. tibialis tibialis Smith 17. Pronotal spine - P. narendrani sp. nov.