Messor

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Messor
Temporal range: 37.2–0 Ma
Eocene – Recent
Messor aegyptiacus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Stenammini
Genus: Messor
Forel, 1890
Type species
Formica barbara, now Messor barbarus
Diversity
159 species
1 fossil species
(Species Checklist)

Messor aegyptiacus casent0281600 p 1 high.jpg

Messor aegyptiacus casent0281600 d 1 high.jpg

Specimen Labels

Synonyms
Evolutionary Relationships
Myrmicinae

Myrmicini
  (2 genera)




Pogonomyrmecini
  (3 genera)



Stenammini


Stenamma
  (85 species)




Novomessor
  (3 species)



Veromessor
  (11 species)






Aphaenogaster
  (225 species)





Aphaenogaster
  (225 species)



Messor
  (159 species)





Goniomma
  (10 species)



Oxyopomyrmex
  (12 species)








Solenopsidini
  (21 genera)




Attini
  (31 genera)



Crematogastrini
  (63 genera)







Based on Ward et al., 2014

Hita Garcia, Wiesel and Fischer (2013) - The more than 160 species (Bolton, 2012) are distributed across the Holarctic, frotropical, and Oriental regions, with its highest diversity found in the Palaearctic region. Messor is a genus of primarily granivorous ants that play an important role in seed dispersal. These ants are commonly encountered in savannahs, grasslands, or even more arid habitats like semi-deserts and deserts (Bolton, 1982).

Identification

Bolton (1981) - The closest relatives of Messor are the genera Aphaenogaster and Pheidole Westwood. Members of the latter genus are easily separated from Messor as the palp formula is reduced to 2,2, its species are dimorphic, and the antennal funiculus ends in a strongly defined 3-segmented club. Aphaenogaster, which is absent from sub-Saharan Africa, is more difficult to differentiate as its species, apart from being uniformly monomorphic, are very close to Messor and share most of its diagnostic characters, including the filiform to feebly clavate funiculi and high palp formula (PF) count. Of 55 species of Aphaenogaster dissected 31 had PF 5,3, and 24 had PF 4,3. For some reason, although species with the higher PF apparently outnumber those with the lower count, the zoogeographical distribution of the latter is much wider than that of the former. Aphaenogaster species with PF 5,3 are found in the Nearctic, Palaearctic and Oriental regions; species with PF 4,3 are also found in these three regions and in the Neotropical, Malagasy, Indo-Australian and Australasian regions as well.

Messor

Mostly polymorphic species (a very few feebly polymorphic and monomorphic species known).

Mostly with ammochaete hairs present (reduced in a few species).

Head massive and broad, in medium to large workers CI > 90 (range 95-125 in 64 species measured).

Metasternal process large to very large, always very conspicuous (45 species dissected).

Outer margins of mandibles strongly curved towards midline, the mandibles massive and heavy.

Aphaenogaster

Entirely monomorphic.

Mostly without ammochaete hairs (present in a very few species).

Head usually slender, CI 90 at maximum, generally much less (range 49-90 in 75 species measured).

Metasternal process small to absent, approaching size seen in Messor only in A. subterranea (55 species dissected).

Outer margins of mandibles not strongly curved towards midline, the mandibles triangular in shape and not massive.

Keys including this Genus

Keys to Subgenera or Species Groups in this Genus

Keys to Species in this Genus

Distribution

Bolton (1982) - The main base of the genus is in the Palaearctic region where about 70-80 species occupy a broad strip of territory reaching across the whole width of North Africa and the southern European countries, across the Near and Middle East and thence eastwards through the U.S.S.R. to China and Japan. Compared to this the faunas of other zoogeographical regions are relatively minor. The Afrotropical region has 12 species and Madagascar has 1; the Oriental region has 3-4 species and the Nearctic has 8, all distributed on the western side of the continent and formerly occupying a genus of their own, Veromessor, now synonymized. Species of Messor are absent from the Neotropical region, the Indo-Australian region and Australasia, nor do they occur on any of the Pacific island systems.

World distribution based on political regions. View/Edit Data
Messor Distribution.png Worlddistribution legend.jpg

Species richness

Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data

Messor Species Richness.png

Biology

Messor is a moderately sized genus of granivorous ants occurring in grassland and savannah, and in arid to desert situations. Knowledge of the detailed biology of the species is sparse, but good basic work has been done on some African species by Levieux & Diomande (1978), and Levieux (1979).

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • MESSOR [Myrmicinae: Pheidolini]
    • Messor Forel, 1890a: lxviii [as subgenus of Aphaenogaster]. Type-species: Formica barbara, by subsequent designation of Bingham, 1903: 277.
    • Messor subgenus of Aphaenogaster: Dalla Torre, 1893: 98; Forel, 1899c: 59.
    • Messor subgenus of Stenamma: Emery, 1895c: 298; Forel, 1903a: 693.
    • Messor raised to genus: Bingham, 1903: 277.
    • Messor senior synonym of Cratomyrmex: Emery, 1924d: 357; Bolton, 1982: 338.
    • Messor senior synonym of Veromessor (and its junior synonym Lobognathus): Bolton, 1982: 338.
  • CRATOMYRMEX [junior synonym of Messor]
    • Cratomyrmex Emery, 1892d: 572. Type-species: Cratomyrmex regalis, by monotypy.
    • Cratomyrmex subgenus of Messor: Santschi, 1920d: 378.
    • Cratomyrmex junior synonym of Messor: Emery, 1924d: 357.
    • Cratomyrmex revived from synonymy: Bernard, 1971: 6.
    • Cratomyrmex junior synonym of Messor: Bolton, 1982: 338.
  • LOBOGNATHUS [junior synonym of Messor]
    • Lobognathus Enzmann, J. 1947b: 152 [as subgenus of Veromessor]. Erroneous entry for Veromessor lobognathus and hence junior synonym of Veromessor: Brown, 1949a: 49
    • Lobognathus junior synonym of Messor: Bolton, 1982: 338.
  • VEROMESSOR [junior synonym of Messor]
    • Veromessor Forel, 1917: 235 [as subgenus of Novomessor]. Type-species: Aphaenogaster andrei, by subsequent designation of Emery, 1921f: 67.
    • Veromessor raised to genus: Wheeler, W.M. 1922a: 661.
    • Veromessor senior synonym of Lobognathus: Brown, 1949a: 49.
    • Veromessor junior synonym of Messor: Bolton, 1982: 338.
  • SPHAEROMESSOR [unavailable name]
    • Sphaeromessor Bernard, 1985: 48. Unavailable name. Proposed without designation of type-species and therefore unavailable. Species included by Bernard (1985) are all referable to Messor: Bolton, 1995b: 46.

Bolton (1982):

Recent studies of Messor include those of Arnoldi (1977) on the fauna of the U.S.S.R., and Collingwood (1978) on the species of the Iberian Peninsula. The only previous synthesis of sub-Saharan African species is that of Arnold (1920), for the then-recognized South African forms, but no key was given in that revue. Creighton (1950) has keyed the North American species formerly in Veromessor.

Worker

Granivorous myrmicine ants, mostly strongly polymorphic but a few monomorphic or only weakly polymorphic. Head massively constructed in larger workers. Mandibles large and powerful, multidentate in smaller workers (up to 15 teeth) but this number usually decreasing with increased body size until in largest workers only a few massive teeth or an edentate crushing edge remains. Sometimes also in small workers the teeth are worn down to an edentate margin. Palp formula predominantly 4,3 but in largest workers usually 5,3 (30 species dissected). Median portion of clypeus broad and shield-like, broadly inserted between the widely separated frontal lobes; both median and lateral portions of clypeus unmodified except for a central impression of the anterior margin in some species. Frontal lobes short but conspicuous, at least partially concealing the antennal insertions. Frontal carinae absent. Antennal scrobes absent. Antennae 12-segmented, either filiform and without an apical club (in which case the flagellar segments gradually increase in size apically), or with a feebly defined incipient club where the apical 3-4 segments are slightly enlarged. Eyes present, moderate to large in size, situated at or just behind the midlength of the sides in full-face view. Ventral surface of head with elongate ammochaete hairs which usually form a psammophore. This may be reduced and non-functional in some species but the hairs are still conspicuous and generally longer than those found elsewhere on the body; in a few species the psammophore is better developed in smaller than in larger workers. With the alitrunk in profile the promesonotum swollen and convex, frequently dome-like and sloping down steeply behind to the metanotal groove which is weakly to distinctly impressed. Propodeum rounded to strongly bispinose posteriorly and on a much lower level than the convex promesonotum. Promesonotal suture fused and inflexible but its track represented by a distinct arched impression across the dorsum. Mesonotum bounded by impressions on all sides, its boundary easily discernible except in the smallest workers of a few species. Metapleural lobes absent or at most represented by a pair of low broadly rounded ridges. Propodeal spiracle large and conspicuous, circular to subcircular and situated approximately at the midlength of the propodeum or sometimes slightly behind the midlength, but never shifted conspicuously back towards the declivity. Basal posterior portion of mesopleuron just above the middle coxa with a few hairs projecting downwards and backwards. (Whether these are guard-hairs indicating the exit site of a gland is not known, but the hairs remain even in species where other body pilosity is very reduced or absent.) Spurs on posterior tibiae varying from very feebly pectinate through partially barbate and minutely barbulate to simple. Alitrunk ventrally with a strong metasternal process which is usually large to very large (reduced but still conspicuous only in Messor rufotestaceus and Messor vaucheri out of 45 species dissected). Petiole with a long anterior peduncle, the spiracle situated at about the midlength of the peduncle, well in front of the node. Petiole node in profile narrow and often bluntly triangular to conical in shape, but frequently a sloping differentiated dorsal surface is present where the anterodorsal angle is generally the highest point.

References

  • Arnold, G. 1920a. A monograph of the Formicidae of South Africa. Part IV. Myrmicinae. Ann. S. Afr. Mus. 14: 403-578 (page 404, Messor in Myrmicinae, Pheidolini; Messor as genus)
  • Ashmead, W. H. 1905c. A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. Can. Entomol. 37: 381-384 (page 383, Messor in Myrmicinae, Myrmicini)
  • Bingham, C. T. 1903. The fauna of British India, including Ceylon and Burma. Hymenoptera, Vol. II. Ants and Cuckoo-wasps. London: Taylor and Francis, 506 pp. (page 277, Type-species: Formica barbara, by subsequent designation; Messor as genus)
  • Bolton, B. 1982. Afrotropical species of the myrmecine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology, 46: 307-370 (page 338, Messor senior synonym of Cratomyrmex: Messor senior synonym of Veromessor (and its junior synonym Lobognathus))
  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 231, Messor as genus; in Myrmicinae, Pheidolini)
  • Bondroit, J. 1918. Les fourmis de France et de Belgique. Ann. Soc. Entomol. Fr. 87: 1-174 (page 149, Messor as genus)
  • Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 98, Messor in Myrmicinae; Messor as subgenus of Aphaenogaster)
  • Emery, C. 1895d. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 257-360 (page 298, Messor as subgenus of Stenamma)
  • Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 769, Messor in Myrmicinae, Myrmicini; Messor as subgenus of Stenamma)
  • Emery, C. 1908f. Beiträge zur Monographie der Formiciden des paläarktischen Faunengebietes. (Hym.) Teil III. Dtsch. Entomol. Z. 1908: 437-465 (page 437, Messor as genus)
  • Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 40, Messor in Myrmicinae, Pheidolini)
  • Emery, C. 1921c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174A:1-94 94: 1-94 + 7 (page 68, Messor in Myrmicinae, Pheidolini [subtribe Stenammini]; Messor as genus)
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 357, Messor senior synonym of Cratomyrmex)
  • Forel, A. 1890b. Fourmis de Tunisie et de l'Algérie orientale. Ann. Soc. Entomol. Belg. 34:lxi-lxxvi. (page lxvii, Messor as subgenus of Aphaenogaster)
  • Forel, A. 1899e. Formicidae. [part]. Biol. Cent.-Am. Hym. 3: 57-80 (page 59, Messor in Myrmicinae, Myrmicini; Messor as subgenus of Aphaenogaster)
  • Forel, A. 1903a. Les Formicides de l'Empire des Indes et de Ceylan. Part X. J. Bombay Nat. Hist. Soc. 14: 679-715 (page 693, Messor as subgenus of Stenamma)
  • Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 241, Messor in Myrmicinae, Pheidolini; Messor as genus)
  • Plowes, N.J.R., Johnon, R.A. & Holldobler, B. 2013. Foraging behavior in the ant genus Messor (Hymenoptera: Formicidae: Myrmicinae). Myrmecological News 18, 33-49.
  • Ruzsky, M. 1905b. The ants of Russia. (Formicariae Imperii Rossici). Systematics, geography and data on the biology of Russian ants. Part I. Tr. Obshch. Estestvoispyt. Imp. Kazan. Univ. 38(4-6 6: 1-800 (page 726, Messor as genus)
  • Steiner, F. M.; Seifert, B.; Grasso, D. A.; Le Moli, F.; Arthofer, W.; Stauffer, C.; Crozier, R. H.; Schlick-Steiner, B. C. 2011. Mixed colonies and hybridisation of Messor harvester ant species (Hymenoptera: Formicidae). Organisms Diversity & Evolution 11:107-134. PDF
  • Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 140, Messor in Myrmicinae, Myrmicini; Messor as genus)
  • Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 661, Messor as genus, Messor in Myrmicinae, Pheidolini ; Messor as genus)