Crematogaster difformis

Crematogaster difformis nests in the hollow rhizomes of the epiphytic fern Lecanopteris sp. and in the enclosed layers of old leaves of another epiphyte fern, Platycerium sp. Both epiphytic ferns establish themselves in the crown of emergent trees in Bornean lowland forests. All mature plants of the two fern species harbour C. difformis, and it always nests within the fern. The ants tend to establish territories encompassing most of the surface areas of the tree crowns where they live, defending not only their host ferns, but also host emergent trees from herbivores inside the territories. Workers of C. difformis prune lianas climbing the emergent trees on which their partner myrmecophytic ferns grow, and the distribution of the lianas is reduced by the presence of C. difformis nests inside the ferns. (Tanaka & Itioka 2011).

Identification
Hosoishi and Ogata (2009) - This species is similar to Crematogaster ampullaris and Crematogaster sewardi, but can be distinguished by the medially directed setae on the posterior portion of the fourth abdominal tergite.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines, Singapore. Oriental Region: Thailand.

Nomenclature

 * . Crematogaster difformis Smith, F. 1857a: 76 (w.) BORNEO (East Malaysia: Sarawak), SINGAPORE.
 * Type-material: lectotype worker (by designation of Hosoishi & Ogata, 2009b: 22), 5 paralectotype workers.
 * Type-locality: lectotype Singapore: “Sing. 25” (A.R. Wallace); paralectotypes: 1 with same data, 4 Malaysia: Sarawak, “Sar. 33” (A.R. Wallace).
 * Type-depository: OXUM.
 * [Misspelled as deformis by Roger, 1863b: 37, and many others; misspelled as diformis by Wheeler, W.M. 1919e: 74.]
 * Emery, 1901g: 574 (q.); Forel, 1909d: 225 (m.); Wheeler, G.C. & Wheeler, J. 1952b: 261 (l.).
 * Combination in C. (Physocrema): Forel, 1912f: 220.
 * Status as species: Smith, F. 1858b: 137; Mayr, 1862: 767; Mayr, 1863: 404; Roger, 1863b: 37; Mayr, 1867a: 105 (redescription); Smith, F. 1871a: 329; Mayr, 1872: 153; Mayr, 1879: 680 (in key); Emery, 1887b: 467; Emery, 1889b: 506; André, 1892b: 53; Dalla Torre, 1893: 81; Emery, 1893e: 193; Emery, 1897d: 567; Emery, 1900d: 690; Emery, 1901g: 574; Forel, 1903a: 682; Bingham, 1903: 145; Wheeler, W.M. 1908d: 390; Forel, 1909d: 225; Forel, 1910d: 124; Forel, 1911b: 201; Forel, 1912n: 57; Forel, 1913k: 78; Forel, 1915a: 28; Viehmeyer, 1916a: 126; Wheeler, W.M. 1919e: 74; Emery, 1922e: 139; Wheeler, W.M. 1924b: 246; Donisthorpe, 1932c: 450; Menozzi, 1935a: 114; Wheeler, W.M. 1937a: 23; Donisthorpe, 1941l: 226 (in key); Chapman & Capco, 1951: 102; Baltazar, 1966: 251; Bolton, 1995b: 152; Jaitrong & Nabhitabhata, 2005: 18; Hosoishi & Ogata, 2009b: 22 (redescription); Pfeiffer, et al. 2011: 45; Khachonpisitsak, et al. 2020: 87.
 * Senior synonym of edentata: Emery, 1901g: 574; Wheeler, W.M. 1919e: 74; Emery, 1922e: 140; Bolton, 1995b: 152; Hosoishi & Ogata, 2009b: 22.
 * Distribution: Brunei, Indonesia (Java), Malaysia (Peninsula, Sabah, Sarawak), Singapore, Thailand.
 * edentata. Crematogaster edentata Mayr, 1867a: 104, pl. 2, fig. 10 (q.) INDONESIA (Java).
 * Type-material: holotype queen.
 * Type-locality: Indonesia: Java (no collector’s name).
 * Type-depository: uncertain.
 * [Note: may be in NHMW, but text says “Mus. Halle” (= Stadtmuseum Halle ?).]
 * Status as species: Dalla Torre, 1893: 81.
 * Junior synonym of difformis: Emery, 1901g: 574; Wheeler, W.M. 1919e: 74; Emery, 1922e: 140; Bolton, 1995b: 152; Hosoishi & Ogata, 2009b: 22.

Worker
Hosoishi and Ogata (2009) - HW 0.88–1.5; HL 0.84–1.34; CI 105–112; SL 0.74–1.06; SI 71–85; EL 0.15–0.28; PW 0.46–0.82; WL 1.01–1.74; PSL 0; PtL 0.26–0.48; PtW 0.19–0.4; PtH 0.15–0.26; PpL 0.16–0.28; PpW 0.2–0.4; PtHI 54–65; PtWI 74–95; PpWI 121–143; WI 90–107 (Three workers measured).

Workers with pronounced size polymorphism.

Scape just or not reaching posterior corner of head in large workers. Anterior-most portions of clypeus distinctly protruded anteriorly in large workers.

In lateral view, pronotum and mesonotum forming a single convexity; propodeum slightly raised relative to promesonotum. Anterior margin of pronotal collar slightly concave in dorsal view. Promesonotal suture sometimes visible in large workers. Metanotal groove convex posteriorly in dorsal view, deep and situated posteriorly to the posterior ridge of pronotum in lateral view; thorax strongly constricted in middle in dorsal view. In dorsal view, some longitudinal rugulae connecting between mesonotum and propodeum; the boundary distinct. Propodeal spiracle situated away from the metapleural gland orifice, the distance between them much greater than the propodeal spiracle diameter. Propodeal spines absent.

Clypeus sculptured with longitudinal rugulae.

Standing pilosity sparse on dorsal face of head, abundant on promesonotum. Dorsal face of head with decumbent setae. Clypeus with short setae. Fourth abdominal tergite with appressed setae. Dorsal setae on fourth abdominal tergite appressed and directed medially in the posterior portion.

Body color black.

Type Material
Hosoishi and Ogata (2009) - LECTOTYPE worker (large worker from SINGAPORE, TYPE HYM: 1017 1-2 / 6) (by present designation) and five paralectotype workers: one paralectotype worker from SINGAPORE; four paralectotype workers from MALAYSIA: Sarawak, Borneo [examined]. We have not been able to examine type-material of C. edentata Mayr. Although Emery synomymised it with C. (P.) difformis, it is impossible to clarify the synonymy from the original description and figure.

Crematogaster difformis

Six worker syntypes in. Labelled “Sing. 25” and “Sar. 33.” Both localities are recorded by Smith.

References based on Global Ant Biodiversity Informatics

 * André E. 1892. Voyage de M. Chaper à Bornéo. Catalogue des fourmis et description des espèces nouvelles. Mém. Soc. Zool. Fr. 5: 46-55.
 * Asfiya W., R. Ubaidillah, and Sk. Yamane. 2008. Ants (Hymenoptera: Formicidae) of the Krakataus, and Sebesi and Sebuku islands. Treubia 36: 1-9.
 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Chung A.Y.C., and M. Mohamed. 1996. A comparative study of the ant fauna in a primary and secondary forest in Sabah, Malaysia. In Edwards, D.S. Booth, W.E. and S.C. Choy (eds). Tropical Rainforest Research. Kluwer Academic Publishers. Pp 357-366.
 * Davidson D. W., S. C. Cook, R. R. Snelling and T. H. Chua. 2003. Explaining the Abundance of Ants in Lowland Tropical Rainforest Canopies. Science 300: 969-972.
 * Donisthorpe H. 1941. Description of a new species of Crematogaster Lund, subgenus Physocrema Forel, with a list of, and a key to, the known species of the subgenus. Entomologist 74: 225-227.
 * Emery C. 1887. Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia (continuazione e fine). [concl.]. Ann. Mus. Civ. Stor. Nat. 25(5): 427-473.
 * Emery C. 1893. Formicides de l'Archipel Malais. Revue Suisse de Zoologie 1: 187-229.
 * Emery C. 1901. Formiciden von Celebes. Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 14:565-580.
 * Emery C. Formiche raccolte da Elio Modigliani in Sumatra, Engano e Mentawei. Annali del Museo Civico di Storia Naturale 40: 661-722.
 * Emery, C.. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza. Formiche della regione Indo-Malese e dell'Australia (continuazione e fine)." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 5, no. 25 (1887): 427-473.
 * Emery, C.. "Formiche raccolte da Elio Modigliani in Sumatra, Engano e Mentawei." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 20, no. 40 (1900): 661-722.
 * Emery, C.. "Voyage de MM. Bedot et Pictet dans l'Archipel Malais. Formicides de l'Archipel Malais." Revue Suisse de Zoologie 1 (1893): 187-229.
 * Forel A. 1903. Les Formicides de l'Empire des Indes et de Ceylan. Part X. J. Bombay Nat. Hist. Soc. 14: 679-715.
 * Forel A. 1909. Ameisen aus Java und Krakatau beobachtet und gesammelt von Herrn Edward Jacobson. Notes Leyden Mus. 31: 221-232.
 * Forel A. 1911. Ameisen aus Java beobachtet und gesammelt von Herrn Edward Jacobson. II. Theil. Notes Leyden Mus. 33: 193-218.
 * Forel A. 1912. Einige neue und interessante Ameisenformen aus Sumatra etc. Zool. Jahrb. Suppl. 15: 51-78.
 * Forel A. 1913. Wissenschaftliche Ergebnisse einer Forschungsreise nach Ostindien ausgeführt im Auftrage der Kgl. Preuss. Akademie der Wissenschaften zu Berlin von H. v. Buttel-Reepen. II. Ameisen aus Sumatra, Java, Malacca und Ceylon. Gesammelt von Herrn Prof. Dr. v. Buttel-Reepen in den Jahren 1911-1912. Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 36:1-148.
 * Forel A. 1915. Fauna Simalurensis. Hymenoptera Aculeata, Fam. Formicidae. Tijdschr. Entomol. 58: 22-43.
 * Gay H., and R. Hensen. 1992. Ant specificity and behaviour in mutualisms with epiphytes: the case of Lecanopteris (Polypodiaceae). Biological Journal of the Linnean Society 47: 261-284.
 * Hashimoto Y., Y. Morimoto, E. S. Widodo, and M. Mohamed. 2006. Vertical distribution pattern of ants in a Bornean tropical rainforest (Hymenoptera: Formicidae). Sociobiology 47(3): 697- 710.
 * Herwina H., and K. Nakamura. 2007. Ant species diversity study using pitfall traps in a small yard in Bogor Botanic garden, West Java, Indonesia. Treubia 35: 99-116.
 * Hosoichi S., and K. Ogata. 2009. A taxonomic revision of the Asian endemic subgenus Physocrema of the genus Crematogaster (Hymenoptera: Formicidae). Zootaxa 2062: 15-36.
 * Hosoishi S. and K. Ogata. 2009. A check list of the ant genus Crematogaster in Asia (Hymenoptera: Formicidae). Bull. Inst. Trop. Agr. Kyushu Univ. 32: 43-83.
 * IZIKO South Africa Museum Collection
 * Ito, F.; Yamane, S.; Eguchi, K.; Noerdjito, W. A.; Kahono, S.; Tsuji, K.; Ohkawara, K.; Yamauchi, K.; Nishida, T.; Nakamura, K. 2001. Ant species diversity in the Bogor Botanic Garden, West Java, Indonesia, with descriptions of two new species of the genus Leptanilla (Hymenoptera, Formicidae). Tropics 10:379-404.
 * Jaitrong W., and T. Ting-Nga. 2005. Ant fauna of Peninsular Botanical Garden (Khao Chong), Trang Province, Southern Thailand (Hymenoptera: Formicidae). The Thailand Natural History Museum Journal 1(2): 137-147.
 * Jaitrong W.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
 * Katayama M., K. Kishimoto-Yamada, H. O. Tanaka, T. Endo, Y. Hashimoto, Sk. Yamane, and T. Itioka. 2015. Negative correlation between ant and spider abundances in the canopy of a Bornean tropical rain forest. Biotropica (in press).
 * Menozzi C. 1935. Formiche indo-australiane del genere Crematogaster Lund raccolte da W. Karawaiew. Konowia. 14: 103-116.
 * Mohamed M. 1995. A preliminary list of ants (Hymenoptera: Formicidae) of the Tawau Hills Park, Sabah. In: Ghazally Ismail  et al.  (eds.),  Tawau  Hills Park,  Sabah,  Pelanduk Pub.  Pp.  205-213.
 * Overbeck H. 1924. A List of Ants from Singapore and Neighbouring Places. Journal of the Malayan Branch of the Royal Asiatic Society 2 (1): 25-40.
 * Pfeiffer M., D. Mezger, and J. Dyckmans. 2013. Trophic ecology of tropical leaf litter ants (Hymenoptera: Formicidae) - a stable isotope study in four types of Bornean rain forest. Myrmecological News 19: 31-41.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Rizali A., A. Rahim, B. Sahari, L.B. Prasetyo, and D. Buchori. 2011. Impact of invasive ant species in shaping ant community structure on small islands in Indonesia. Jurnal Biologi Indonesia 7(2): 221-230.
 * Rizali A., M. M. Bos, D. Buchori, Sk. Yamane, and C. H. Schulze. 2008. Ants in tropical urban habitats: the myrmecofauna in a densely populated area of Bogor, West Java, Indonesia. Hayati Journal of Biosciences 15(2): 77-84.
 * Rizali A., M.M. Bos, D. Buchori, Sk. Yamane, C. Hans, and J. Schulze. 2008. Ants in tropical urban habitats: the myrmecofauna in a densely populated area of Bogor, West Java, Indonesia. Hayati Journal of Biosciences 77-84.
 * Santschi F. 1928. Fourmis de Sumatra, récoltées par Mr. J. B. Corporaal. Tijdschrift voor Entomologie 71: 119-140.
 * Smith, F.. "Catalogue of the hymenopterous insects collected at Sarawak, Borneo; Mount Ophir, Malacca; and at Singapore, by A. R. Wallace." Journal of the Proceedings of the Linnean Society of London, Zoology 2 (1857): 42-88.
 * Tanaka H. O., S. Yamane, and T. Itioka. 2012. Effects of a fern-dwelling ant species, Crematogaster difformis, on the ant assemblages of emergent trees in a Bornean tropical rainforest. Ann. Entomol. Soc. Am. 105(4): 592-598.
 * Wheeler W. M. 1919. The ants of Borneo. Bulletin of the Museum of Comparative Zoology 63:43-147.
 * Wheeler W. M. 1937. Additions to the ant-fauna of Krakatau and Verlaten Island. Treubia 16: 21-24.
 * Wheeler, William Morton. 1924. Ants of Krakatau and Other Islands in the Sunda Strait. Treubia. 5(1-3):1-20.
 * Widodo E. S., T. Naito, M. Mohamed, and Y. Hashimoto. 2004. Effects of selective logging on the arboreal ants of a Bornean rainforest. Entomological Science 7: 341-349.
 * Yamane S., T. Itino, and A.R. Nona. 1996. Ground ant fauna in a Bornean dipterocarp forest. Raffles Bulletin of Zoology 44(1): 253-262.
 * Yamane Sk. 2005. Krakatau in 1982, and the commencement of myrmecological research. The nature and Insects (Konchu to shizen) 40: 27-33.