Zootaxa 2845: 1–174 (2011) ISSN 1175-5326 (print edition) Monograph www.mapress.com/zootaxa/ ZOOTAXA Copyright © 2011 · Magnolia Press ISSN 1175-5334 (online edition) ZOOTAXA 2845 Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) BRIAN E. HETERICK1 & STEVE SHATTUCK2 1 Curtin University of Technology, GPO Box U1987, Perth WA 6845, Australia 2 CSIRO Ecosystem Science, P. O. Box 1700, Canberra ACT 2601, Australia Magnolia Press Auckland, New Zealand Accepted by J. Longino: 1 Dec 2010; published: 29 Apr. 2011 BRIAN E. HETERICK & STEVE SHATTUCK Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) (Zootaxa 2845) 174 pp.; 30 cm. 29 Apr. 2011 ISBN 978-1-86977-675-6 (paperback) ISBN 978-1-86977-676-3 (Online edition) FIRST PUBLISHED IN 2011 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: [email protected] http://www.mapress.com/zootaxa/ © 2011 Magnolia Press All rights reserved. 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ISSN 1175-5326 (Print edition) ISSN 1175-5334 (Online edition) 2 · Zootaxa 2845 © 2011 Magnolia Press HETERICK & SHATTUCK Table of contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Taxonomic history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Biology and Ecology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 The current position of Iridomyrmex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Iridomyrmex Mayr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Iridomyrmex species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Key to Iridomyrmex species based on workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 Iridomyrmex adstringatus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 Iridomyrmex agilis Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 Iridomyrmex alpinus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 Iridomyrmex anceps (Roger) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 Iridomyrmex anderseni Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Iridomyrmex angusticeps Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 Iridomyrmex anteroinclinus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 Iridomyrmex atypicus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 Iridomyrmex azureus Viehmeyer, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 Iridomyrmex bicknelli Emery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 Iridomyrmex bigi Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 Iridomyrmex brennani sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 Iridomyrmex brunneus Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 Iridomyrmex calvus Emery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 Iridomyrmex cappoinclinus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57 Iridomyrmex cephaloinclinus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 Iridomyrmex chasei Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 Iridomyrmex coeruleus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63 Iridomyrmex conifer Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64 Iridomyrmex continentis Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66 Iridomyrmex cuneiceps sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Iridomyrmex cupreus sp. n.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Iridomyrmex curvifrons sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 Iridomyrmex cyaneus Wheeler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71 Iridomyrmex difficilis sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 Iridomyrmex discors Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 Iridomyrmex dromus Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76 Iridomyrmex elongatus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 Iridomyrmex exsanguis Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 Iridomyrmex fulgens sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 Iridomyrmex galbanus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 Iridomyrmex gibbus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84 Iridomyrmex gumnos sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86 Iridomyrmex hartmeyeri Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87 Iridomyrmex hertogi sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88 Iridomyrmex hesperus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 Iridomyrmex infuscus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91 Iridomyrmex innocens Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92 Iridomyrmex lividus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94 Iridomyrmex longisoma sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96 Iridomyrmex luteoclypeatus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Iridomyrmex macrops sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Iridomyrmex mattiroloi Emery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 Iridomyrmex mayri Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101 Iridomyrmex meridianus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103 Iridomyrmex minor Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104 Iridomyrmex mirabilis sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107 Iridomyrmex mjobergi Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 REVISION OF THE ANT GENUS IRIDOMYRMEX Zootaxa 2845 © 2011 Magnolia Press · 3 Iridomyrmex neocaledonica sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111 Iridomyrmex niger sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112 Iridomyrmex nudipes sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113 Iridomyrmex obscurior Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Iridomyrmex obsidianus Emery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116 Iridomyrmex omalonotus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118 Iridomyrmex pallidus Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Iridomyrmex phillipensis sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122 Iridomyrmex prismatis Shattuck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Iridomyrmex purpureus (F. Smith) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124 Iridomyrmex reburrus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127 Iridomyrmex roseatus sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128 Iridomyrmex rubriceps Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130 Iridomyrmex rufoinclinus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132 Iridomyrmex rufoniger (Lowne) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133 Iridomyrmex sanguineus Forel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136 Iridomyrmex setoconus Shattuck & McMillan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 Iridomyrmex spadius Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138 Iridomyrmex splendens Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139 Iridomyrmex spodipilus Shattuck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141 Iridomyrmex spurcus Wheeler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142 Iridomyrmex suchieri Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Iridomyrmex suchieroides sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146 Iridomyrmex tenebrans sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147 Iridomyrmex tenuiceps sp. n.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Iridomyrmex trigonoceps sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150 Iridomyrmex turbineus Shattuck & McMillan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151 Iridomyrmex victorianus Forel, stat. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153 Iridomyrmex viridiaeneus Viehmeyer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155 Iridomyrmex viridigaster Clark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156 Iridomyrmex xanthocoxa sp. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158 Species inquirenda in Iridomyrmex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165 Iridomyrmex bicknelli luteus Forel, species inquirenda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165 Species removed from Iridomyrmex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165 Anonychomyrma extensa (Emery), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165 Chronoxenus butteli (Forel), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166 Tapinoma krakatauae (Wheeler), comb. nov . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166 Tapinoma latifrons (Karavaiev), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167 Fossil-based species of Iridomyrmex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167 Iridomyrmex breviantennis Théobald, incertae sedis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .167 Iridomyrmex florissantius Carpenter, incertae sedis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168 Iridomyrmex mapesi Wilson, incertae sedis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168 Iridomyrmex obscurans Carpenter, incertae sedis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168 Iridomyrmex shandongicus Zhang . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168 Fossil-based species removed from Iridomyrmex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169 Anonychomyrma constricta (Mayr) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169 Anonychomyrma geinitzi (Mayr), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169 Anonychomyrma samlandica (Wheeler) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169 Ctenobethylus goepperti (Mayr) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169 Dolichoderus haueri (Mayr), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 Eldermyrmex Shattuck gen. n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 Eldermyrmex oblongiceps (Wheeler), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 Gracilidris humiloides (Wilson) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 Liometopum bogdassarovi (Nazaraw, Bagdasaraw & Uriew), comb. nov. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 Technomyrmex hispaniolae (Wilson) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 4 · Zootaxa 2845 © 2011 Magnolia Press HETERICK & SHATTUCK Abstract The world fauna of the dolichoderine ant genus Iridomyrmex (Hymenoptera: Formicidae) is revised. Seventy-nine species are recognised, 31 described as new. Four species are removed from Iridomyrmex: I. butteli (Forel) to Chronoxenus, I. extensus Em- ery to Anonychomyrma and I. krakatauae Wheeler and I. latifrons Karavaiev to Tapinoma. Twenty-five species and subspecies pass into synonymy: I. emeryi Crawley is synonymised under I. victorianus Forel (itself raised to species), I. vicinus Clark is synonymised under I. splendens Forel (itself raised to species), I. wingi Donisthorpe is synonymised under I. pallidus Forel (itself raised to species), I. gracilis Lowne (a preoccupied name) is synonymised under I. bicknelli Emery, I. mimulus Shattuck is syn- onymised under I. viridigaster Clark, I. albitarsus Wheeler and I. notialis Shattuck are synonymised under I. calvus Emery, I. obscurus Crawley is synonymised under I. suchieri Forel (itself raised to species), I. greensladei Shattuck is synonymised under I. purpureus, I. variscapus Shattuck is synonymised under I. bigi Shattuck, and I. meinerti Forel is synonymised under I. anceps Roger. Of the subspecies, I. anceps formosae Forel, I. anceps ignobilis Mann, I. rufoniger metallescens Emery, I. anceps sikki- mensis Forel and I. anceps watsonii Forel are synonymised under I. anceps, Iridomyrmex bicknelli splendidus Forel is syn- onymised under I. bicknelli Emery, I. rufoniger fusciventris Forel is synonymised under I. brunneus Forel (itself raised to species), I. chasei concolor Forel and I. chasei yalgooensis Forel are synonymised under I. chasei Forel, I. rufoniger incertus Forel is synonymised under I. pallidus, I. rufoniger domesticus Forel and I. rufoniger septentrionalis Forel are synonymised un- der I. rufoniger Lowne, and I. mattiroloi parcens Forel is synonymised under I. victorianus. In addition to the five taxa mentioned above, the subspecies I. bicknelli azureus Viehmeyer, I. bicknelli brunneus Forel, I. mattiroloi continentis Forel, I. gracilis minor Forel, I. gracilis rubriceps Forel and I. gracilis spurcus Forel are raised to species. A single species, I. bicknelli luteus Forel, could not be identified and is treated as species inquirenda. A key to workers of the genus is supplied. Lectotypes are designated for I. brunneus Forel, I. chasei Forel, I. conifer Forel, I. discors Forel, I. minor Forel, I. mjobergi Forel, I. pallidus Forel, I. suchieri Forel and I. victorianus Forel. Neotypes are established for I. anceps (Roger), I. parcens Forel and I. rufoniger (Lowne). Five fossil species are considered to belong to Iridomyrmex, although only one of these is supported by rigorous morphological data. Four fossil species are regarded as incertae sedis within the genus. The following fossil-based species are removed from Iridomyrmex (all new combinations): geinitzi Mayr to Anonychomyrma, haueri Mayr to Dolichoderus, oblongiceps Wheeler to Eldermyrmex (gen. n.) and bogdassarovi Nazaraw, Bagdasaraw & Uriew to Liometopum. Key words: Hymenoptera, Formicidae, Dolichoderinae, Iridomyrmex, taxonomy, new species, SE Asia, Australia. Introduction The ant genus Iridomyrmex belongs to the subfamily Dolichoderinae. All members of this subfamily are readily characterised as possessing a slit-like opening on the underside of the end of the abdomen (i.e., that part of the ant abdomen known as the gaster). This opening is the means by which various chemicals, e.g., for defence or trail- marking, can be disseminated to the environment. Iridomyrmex is a quintessentially Australian phenomenon. Although a small handful of species range as far away as India and China, the vast bulk of the taxa of this ecologi- cally important and speciose genus is restricted to Australia. Within Australia, members of the genus are a conspic- uous part of most ecosystems, although they tend to avoid the very moist areas such as wet sclerophyll and rain forests (Shattuck, 1992b). Taxonomic history The genus Iridomyrmex was erected by Mayr in 1862, although the type-species was not designated until 1903 (Bingham, 1903). The type-species Iridomyrmex detecta had previously become a junior synonym of I. purpureus (F. Smith) (Lowne, 1865a). In this early period, ant subfamily classification was confused, and it was not until 1878, 16 years after publication of the formal diagnosis of genus Iridomyrmex, that Forel established the subfamily Dolichoderinae (as ‘Dolichoderidae’) (Forel, 1878a). Iridomyrmex was placed in that subfamily later in the same year (Forel, 1878b). From the time of its inception, the genus Iridomyrmex (Fig. 1A–I) has also suffered from a confused taxo- nomic understanding, not least because of the failure of early researchers to identify easy-to-recognise diagnostic features. Some diagnostic characters used, such as the morphology of the proventriculus, were not so much unreli- able as unwieldy and made separation of dolichoderine genera difficult for most researchers. The result was the gradual development of a portmanteau genus containing unrelated ants, and taxonomic instability that multiplied with the accumulation of new forms (Shattuck, 1992b). Brown (1958) was probably the first myrmecologist to REVISION OF THE ANT GENUS IRIDOMYRMEX Zootaxa 2845 © 2011 Magnolia Press · 5 6 · Zootaxa 2845 © 2011 Magnolia Press HETERICK & SHATTUCK FIGURE 1. Iridomyrmex workers. A. An I. dromus worker foraging on a Eucalyptus trunk in dry sclerophyll woodland. This ant was part of a loose foraging column between a feeding area high in the tree and the colony’s soil-based nest. B. Iri- domyrmex reburrus forms large nests containing tens of thousands of workers. Workers forage in high concentrations in the vicinity of the nest. C. Iridomyrmex discors, while generally uncommon, can occur in large numbers at suitable sites. D. Iri- domyrmex lividus is a distinctive and common ant of the southern arid zone. E. Iridomyrmex alpinus is one of the most com- mon and obvious species in the High Country of south-eastern Australia. While ground-nesting, it forages both on the ground and on vegetation including trees. F. Like most species of Iridomyrmex, I. purpureus workers are highly visual and interactive, communicating with each other as well as attacking intruders to their territories. strongly question the monophyly of Iridomyrmex, when he indicated that the Argentine ant (then Iridomyrmex humilis Mayr) differed from the true Indo-Australian Iridomyrmex by reason of its ‘internal characters’. The same author (Brown, 1977) elaborated on those differences when he stated that the Indo-Australian Iridomyrmex lack Pavan’s apparatus, whereas the Argentine ant and its new World relatives possess this structure. Snelling and Hunt (1975), citing Brown (1958), also queried the placement of New World species in Iridomyrmex. In a separate judgement, based on chromosomal differences, Crozier (1968) suggested ‘Iridomyrmex glaber’ (now Ochetellus glaber (Mayr)) should also be removed from Iridomyrmex. Despite these rumblings of discontent, a proper overhaul of Iridomyrmex only commenced in the early 1990’s. Shattuck (1992a) redefined the genus, and transferred 91 named taxa to six separate dolichoderine genera, three of them new. Anonychomyrma Donisthorpe received 31 taxa, Doleromyrma Forel three taxa, Linepithema Mayr 28 taxa, Ochetellus Shattuck 10 taxa, Papyrius Shattuck five taxa and Philidris Shattuck 14 taxa. Sixty-two named taxa remained in Iridomyrmex. Shattuck (1992b) undertook a generic revision of the entire subfamily Dolichoderi- nae and included a diagnosis of all castes of each genus (insofar as these were known). Diagnostic features for the Iridomyrmex worker were all cephalic, and included the posterior position of the eyes on the head capsule, the pres- ence of shoulders on the anterolateral clypeal margin, and a pointed or rounded projection of the anteromedial cly- peal margin (here termed the anteromedial clypeal prominence). As well as a broad generic analysis of Iridomyrmex, Shattuck, alone or in collaboration, has also revised some of the constituent groupings within the genus, these being the I. purpureus group (Shattuck, 1993a), the I. calvus group (Shattuck, 1993b), the I. discors group (Shattuck, 1996) and the I. conifer group (Shattuck and McMillan, 1998). These are all relatively easily rec- ognised groups with distinctive diagnostic characters, and include most of the larger species. At the time of writing, 79 living taxa (species and subspecies) and a nomen nudum are listed under Iridomyrmex, and there are also five fossil taxa. The development of a robust species-group level classification within the genus has proven problematic with a number of alternative arrangements been proposed (Anderson 2000, 2007; Shattuck, 1993a, 1993b, 1996; Shattuck and McMillan, 1998). Confusingly, there has often not been agreement on the exact boundaries and composition of these groups, further reducing their utility. Pending molecular phylogenetic analyses to test the monophyly of these groups, we have here chosen to emphasize species-level taxonomy rather than possible arrangements of higher groupings. Progress on the species-level taxonomy within Iridomyrmex has been complicated by the conservative and uni- form nature of the taxa: the mandible, palps and antennal segments are uniform across all taxa, the body lacks excrescences of any sort, and the pilosity often appears a trivial character (there are no uniquely informative bris- tles, as in, for example Camponotus, and hairiness is often an intraspecific feature). The often subtle trait antennal scape length is uniform in most taxa and this is a useful character for recognising species, while the appearance of the anteromedial clypeal prominence may be an indicator of deeper radiations at a species-group or species-com- plex level. The appearance of the frontal carinae is occasionally helpful. Minor characters include appearance of the cuticle and presence or absence of a psammophore. Colour is relatively uniform within most species, but is rarely helpful beyond species-level. This lack of substantive or obvious morphological differentiation among taxa and the taxonomic significance of a number of subtle characters have resulted in little progress being made on the species-level taxonomy within the genus, even given the large amounts of material available for study. The apparent reason for the morphologically conservative nature of Iridomyrmex is the exceptionally high spe- ciation rate within the genus (Fig. 5). Based on the work of Ward et al. (2010), the genus Iridomyrmex arose approximately 12 million years ago. The sister group to this genus, Froggattella, has just two species even though it is the same age. To reach the same number of species currently understood to belong to Iridomyrmex requires the inclusion of all eight Indo-Australian dolichoderine genera basal to it, i.e., a total of 73 described species (slightly REVISION OF THE ANT GENUS IRIDOMYRMEX Zootaxa 2845 © 2011 Magnolia Press · 7 fewer than the tally for Iridomyrmex). The age of this clade is estimated at 23 million years. Thus, it would seem that Iridomyrmex has speciated nearly as much in the last 12 million years as its close relatives have over the last 23 million years (acknowledging that extinction will have reduced the number of taxa among the close relatives more than within the much younger Iridomyrmex). This means that the species within Iridomyrmex are relatively young and will not have diverged genetically (and morphologically) to the degree seen in other genera within the subfam- ily. Biology and Ecology (Figs 2A–H, 3A–G, 4A–H) Iridomyrmex species need no introduction for many Australians. The largest species, the meat ants, are a familiar sight in rural areas, and the smaller brown and black species are found in most ecosystems, but are most abundant in the semi-arid and arid zone. Several species are also frequently observed in urban areas. Although generally cat- egorised as ‘aggressive’ (Shattuck, 1999; Andersen, 2000), some species are timorous and avoid combative inter- actions with other organisms, including other ants. Nearly all nests are in soil, either in the open or under rocks, bark, logs or other cover, and the appearance of the entrance may vary from multiple holes surrounded with a large, pebble-strewn mound, to a single small hole, the size of a worker. The size of the nests is variable, from a few hun- dred workers to over 300,000 workers (Shattuck, 1999). Behaviour Many species of Iridomyrmex are extremely aggressive, with workers that are more than willing to attack anything that disturbs their nests or foraging columns. Members of the I. purpureus species group, the “meat ants”, will liter- ally boil from their mounds at the slightest disturbance, attacking any and all intruders. These species are also eco- logically dominant, significantly impacting on the foraging behaviours of other species occurring near their nests because of the large numbers of workers active in these areas. They commonly monopolise food sources and pre- vent access by other species (Andersen and Patel, 1994). Even relatively small species such as I. chasei and I. rufo- niger are notably aggressive and will swarm over those disturbing them, and while they don’t sting, they will give a sharp, painful bite. These species are commonly found in urban areas and while they generally do not enter houses, they can be abundant in yards and gardens where they are mainly a nuisance as they excavate soil from under paving stones and along pathways and bite those approaching their nests. In a few cases these and other spe- cies are known to enter homes in search of food and water, but this is relatively uncommon and generally occurs for only short periods. In contrast to these aggressive species, many species are quite timid, running and hiding when disturbed and avoiding contact with more aggressive ant species. These include I. agilis, I. bicknelli, I. dromus, I. longisoma, I. mjobergi, I. suchieroides and I. victorianus. Among these species, foraging is often undertaken by single workers with recruitment limited to only a few nest mates. When nests are disturbed, workers busy themselves removing exposed brood to safety rather than attacking intruders. While removing soil from nests, workers will ignore nearby disturbances and remain focused on the task at hand. If attempts are made to capture these workers they will scurry out of sight into leaf litter to hide. In extreme cases, such as I. victorianus, workers are known to feign death to avoid capture, lying motionless until the danger has passed. FIGURE 2. Iridomyrmex biology. A. Nest construction is a major undertaking for nearly all ants. This I. bicknelli worker car- ries excavated soil from the nest entrance and will deposit it several centimetres away. B. Iridomyrmex bigi is a nocturnal spe- cies that blocks the nest entrance during the day. These workers are repairing a damaged entrance. C. These I. rufoniger workers are tending a lycaenid butterfly larva. The ants provide protection for the caterpillar in exchange for a sugar and pro- tein-rich meal. D. Iridomyrmex workers forage for a wide range of prey, in this case a termite being carried to an I. pallidus nest. E. While the nutritional value of an insect wing is minimal, this forager nonetheless returned to the nest with one as food for the colony’s larvae. F. An I. rufoniger worker visits a scale insect on a Eucalyptus trunk in search of honeydew excreted from the straw-like process on the homopteran’s posterior surface. G. Iridomyrmex workers are highly effective foragers, as in this case where numerous I. rufoniger workers cooperate to dismember this orthopteran and transport it to their nest. H. These I. chasei workers have been recruited to a butterfly larva discovered several metres from their nest. They work together to sub- due the prey and carry it to their nest. 8 · Zootaxa 2845 © 2011 Magnolia Press HETERICK & SHATTUCK REVISION OF THE ANT GENUS IRIDOMYRMEX Zootaxa 2845 © 2011 Magnolia Press · 9 While meat ants are some of the most aggressive and territorial species in the genus, one species, I. purpureus, has developed elaborate ritualised territorial displays to resolve boundary disputes among closely situated nests (Ettershank and Ettershank, 1982; van Wilgenburg et al., 2005). When members of separate colonies meet, they follow a tightly scripted routine until appeasement occurs. This routine starts with antennation and open mandibu- lar posturing, escalates to body elevation and front leg “kick boxing” and finally progresses to turned gasters and hind leg boxing. This last step continues until one of the combatants backs down, in which case both will enter a period of self-grooming followed by searching for another “foreign” worker. These boundary disputes may con- tinue for months during the summer, and be repeated year after year at essentially the same location. It seems that ultimate resolution is based not on the effectiveness of individual workers but by the number of workers recruited to the battle by each colony; in other words, the larger colony generally wins in the end. Additionally, in a few cases fierce fighting can occur in these ants, sometimes leading to serious injury or death. This sort of fighting is most often initiated by the territory-defending ant while ritualised fighting is most often initiated by the intruding ant. Clearly a range of complex behaviours have developed within these ants relating to colony and territorial defence. Foraging Patterns As far as is known, all species of Iridomyrmex are general predators and scavengers as well as tending a wide range of arthropods for honeydew, including a variety of Hemiptera and lycaenid butterfly larvae. These Hemiptera and caterpillars produce sugary fluids from their digestive systems or specialised glands, and ants will tend and protect these for this reward. Some species will also take plant material, especially the oil and protein rich arils (or elaio- somes) of seeds. Workers subdue or scavenge a wide variety of food items, ranging from the smallest arthropods to the largest dead vertebrates, and show little specialisation or preference for the items taken. They will also forage on flowers of many plants, both to collect nectar and also in search of small prey items. While all forage on the ground, many species will forage on tree-trunks and low vegetation and will even climb high into trees in search of food. The vast majority of Iridomyrmex workers forage during the day in loose columns, although a few (including I. omalonotus and I. rufoniger) will forage at night as well. Some species (for example I. dromus, I. exsanguis, I. hartmeyeri and I. pallidus) are primarily active at night and some will block their nest entrances during the day. Despite this generally nocturnal disposition, most of these species are also diurnally active in suitable conditions. A notable exception is I. bigi, which is apparently strictly nocturnal and firmly blocks its nest entrances during the day, quickly replacing the plug if disturbed. When foraging, most species form large, conspicuous foraging trails between their nests and feeding areas. Ground-based trails can become virtual highways over time, worn smooth and becoming free from plants and sur- face litter. These trails are especially well developed in species such as I. purpureus and I. rufoniger. In a few spe- cies (including I. agilis and I. cephaloinclinus) workers forage singly along well defined but indistinct paths across the ground, scurrying quickly, often with their gasters raised. In other species, intermediate patterns are seen, with workers forming loose foraging trails away from their nests and then dispersing over large areas where they forage individually. Nests Nearly all species of Iridomyrmex are ground nesting, with nests found in the open or under rocks, logs or other objects on the ground. A few species (including I. alpinus, I. mayri, I. meridianus and I. splendens) will nest in rot- ten wood, but generally in these cases soil is also involved. There are a limited number of records of nests being found under bark (for example in I. minor and I. victorianus) but these are uncommon and even those species involved show a preference for nesting in soil. The vast majority of species show little preference for specific soil types with most being found in a wide range of situations. In fact, some species, such as I. bicknelli, can be found nesting in virtually any location, from pure sand beaches to spaces between barren footpaths in large cities. A few species, such as some members of the purpureus group, tend to avoid loose, sandy soil types (Greenslade, 1974), but this is exceptional for the genus. 10 · Zootaxa 2845 © 2011 Magnolia Press HETERICK & SHATTUCK