Phalacromyrmex

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Phalacromyrmex
Phalacromyrmex fugax
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Phalacromyrmex
Kempf, 1960
Type species
Phalacromyrmex fugax
Diversity
1 species
(Species Checklist)

Phalacromyrmex fugax casent0103116 profile 1.jpg

Phalacromyrmex fugax

Phalacromyrmex fugax casent0103116 dorsal 1.jpg

Specimen Label

Evolutionary Relationships
Attini

Ochetomyrmex (2 species), Tranopelta (2 species)




Allomerus (8 species), Blepharidatta (4 species), Diaphoromyrma (1 species), Lachnomyrmex (16 species), Wasmannia (11 species)






Acanthognathus (7 species), Colobostruma (16 species), Daceton (2 species), Epopostruma (19 species), Lenomyrmex (7 species), Mesostruma (9 species), Microdaceton (4 species), Orectognathus (29 species),




Acromyrmex (62 species), Apterostigma (44 species), Atta (19 species), Cyatta (1 species), Cyphomyrmex (23 species), Kalathomyrmex (1 species), Mycetophylax (21 species), Mycetagroicus (4 species), Mycetarotes (4 species), Mycetosoritis (2 species), Mycocepurus (6 species), Myrmicocrypta (31 species), Sericomyrmex (11 species), Trachymyrmex (49 species), Xerolitor (1 species)





Pheidole
  (1,194 species)




Cephalotes
  (119 species)



Procryptocerus
  (45 species)







Strumigenys
  (836 species)




Phalacromyrmex
  (1 species)



Pilotrochus
  (1 species)







Protalaridris
  (7 species)



Rhopalothrix
  (16 species)





Basiceros
  (8 species)




Octostruma
  (34 species)




Eurhopalothrix
  (53 species)



Talaridris
  (1 species)














Based on Ward et al. (2014), Blaimer et al. (2018) and Li et al. (2018).

The only species in the genus, Phalacromyrmex fugax, has been collected in forest habitats. The genus is endemic to Brazil and little is known about the biology of these ants.

Identification

Although quite distinct in its own right, this new genus seems at least superficially related with the ants of the tribe Dacetini in the subfamily Myrmicinae. As regards the number of antennal segments, it agrees with the Daceton-complex, but is otherwise completely different in head shape, short triangular mandibles, position of eyes and development of antennal scrobe. By its general habitus Phalacrornyrmex seemingly imitates the short-mandibulate members of the strumigenys-complex, especially Codiomyrmex and Glamyromyrmex (=Strumigenys). However, many important characters, such as the number of antennal segments, the unarmed petiolar and postpetiolar nodes, lacking any trace of spongiform appendages, the normally ovate gaster, lacking an anterior truncation and transverse crest, separate it also from this group. The peculiar palpal formula - maxillary palps with 3, labial palps with 2 segments - removes Phalacrornyrmex from all known Dacetine genera. As long as the sexual forms and the larvae are unknown, it seems best not to include the present genus in the Dacetini, although it seems even farther removed from all other Myrmecine tribes. (Kempf 1960)

Keys including this Genus

 

Distribution

Distribution and Richness based on AntMaps

Biology

Castes

Nomenclature

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

  • PHALACROMYRMEX [Myrmicinae: Phalacromyrmecini]
    • Phalacromyrmex Kempf, 1960b: 89. Type-species: Phalacromyrmex fugax, by original designation.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Worker - Mandibles short, broadly triangular, strongly curved laterad and apicad; chewing border serially dentate, larger teeth alternating with smaller ones. Labrum bilobed. Palpal formula 3:2. Antennae 11-segmented, funiculus with a 2-segmented apical club. Frontal carinae broadly expanded laterad and foreward, covering cheeks and eyes in full-face view. Clypeus flanked by the frontal carinae, its anterior border scarcely convex. Eyes small, situated ventrolaterally below the deeply excavate antennal scrobe. Thorax dorsally flattened, laterally marginate; mesoepinotum conspicuously compressed. Epinotum with a pair of upright triangular lamellae. Middle and hind legs without a tibial spur. Petiole strongly pedunculate. Both petiolar and postpetiolar nodes little broader than long, unarmed, lacking spongiform appendages. Gaster ovate, its anterior end not truncate, lacking a transverse crest. Body integument mostly smooth and shining. Erect hairs simple, short, very scarce, absent on dorsum of head. Appressed pilosity scarce and inconspicuous.

Baroni Urbani & De Andrade (2007) - Only one unequivocal synapomorphy for this genus results from our data, the presence of mesopleural costulation. CI 1.00, RI 0.00. We doubt, however the generic rank of this character. Other apomorphic characters resulting from our analysis are:

Worker (and gyne?) presence of a cuticular process of the mesonotum. CI 0.86, RI 0.75. Cuticular projections of the mesonotum are known also in Epopostruma and Strumigenys.

Worker (and gyne?) metapleaural gland bulla close to the annulus. CI 0.62, RI 0.40. The same character state is encountered in a number of non-related Dacetini genera like Protalaridris, Microdaceton, Epopostruma, a. o.

Worker (and gyne?) antennae 11-jointed. CI 0.20, RI 0.50. A character state shared with several outgroups and with Daceton and Acanthognathus.

The pretended generic apomorphies above are likely to be a by-product of the clustering together of the three "Phalacromyrmecini" genera, a clustering that is based on weak characters. We suspect that all the former Phalacromyrmecini genera might be better understood as atypical Strumigenys species.

Etymology

phalacros - bald-headed; myrmex - an ant

References

  • Baroni Urbani, C.; De Andrade, M. L. 1994. First description of fossil Dacetini ants with a critical analysis of the current classification of the tribe (Amber Collection Stuttgart: Hymenoptera, Formicidae. VI: Dacetini). Stuttg. Beitr. Naturkd. Ser. B (Geol. Paläontol.) 198: 1-65 (page 31, Phalacromyrmex in Myrmicinae, Dacetini)
  • Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria”. 99:1-191. PDF
  • Bolton, B. 1984. Diagnosis and relationships of the myrmicine ant genus Ishakidris gen. n. (Hymenoptera: Formicidae). Syst. Entomol. 9: 373-382 (page 382, Phalacromyrmex in Myrmicinae, Phalacromyrmex genus group)
  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 193, Phalacromyrmex in Myrmicinae, Phalcromyrmecini)
  • Dlussky, G. M.; Fedoseeva, E. B. 1988. Origin and early stages of evolution in ants. Pp. 70-144 in: Ponomarenko, A. G. (ed.) Cretaceous biocenotic crisis and insect evolution. Moskva: Nauka, 232 pp. (page 80, Phalacromyrmex in Myrmicinae, Phalacromyrmecini)
  • Jaffe, K. 1993. El mundo de las hormigas. Baruta, Venezuela: Equinoccio (Ediciones de la Universidad Simón Bolívar), 188 pp. (page 12, Phalacromyrmex incertae sedis in Myrmicinae (anachronism))
  • Kempf, W. W. 1960b. Phalacromyrmex, a new ant genus from southern Brazil (Hymenoptera, Formicidae). Rev. Bras. Biol. 20: 89-92 (page 89, 90, Phalacromyrmex as genus; Phalacromyrmex incertae sedis in Myrmicinae)
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 182, Phalacromyrmex in Myrmicinae, Dacetini)
  • Kusnezov, N. 1964 [1963]. Zoogeografía de las hormigas en Sudamérica. Acta Zool. Lilloana 19: 25-186 (page 56, Phalacromyrmex in Myrmicinae, Myrmicini)