Pheidole tristis

Nothing is known about the biology of tristis.

Identification
See the description in the nomenclature section.

Distribution
Kempf (1972): southeastern Brazil (Santa Catarina, Sao Paulo, Rio de Janeiro, Parana) and north central Argentina (Misiones).

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Paraguay.

Nomenclature

 * fumipennis. Atta fumipennis Smith, F. 1858b: 169 (w.q.) BRAZIL. Combination in Aphaenogaster: Forel, 1895b: 129; in Pheidole: Donisthorpe, 1932c: 474. Junior synonym of tristis: Brown, 1981: 527.
 * rubra. Atta rubra Smith, F. 1858b: 168 (q.) BRAZIL. Combination in Pheidole: Mayr, 1886c: 360. Junior synonym of tristis: Kempf, 1965: 183.
 *  tristis. Myrmica tristis Smith, F. 1858b: 132 (w.) BRAZIL. Combination in Pheidole: Mayr, 1886c: 360. Senior synonym of emeryi, rubra: Kempf, 1965: 183; of fumipennis: Brown, 1981: 527; of alsia, crassipes: Wilson, 2003: 769.
 * crassipes. Pheidole crassipes Mayr, 1887: 590 (s.), 600 (w.) BRAZIL. Junior synonym of tristis: Wilson, 2003: 769.
 * emeryi. Pheidole emeryi Mayr, 1887: 589 (s.), 599 (w.) BRAZIL. Junior synonym of tristis: Kempf, 1965: 183.
 * alsia. Pheidole emeryi var. alsia Santschi, 1923d: 58 (s.w.) BRAZIL. Subspecies of tristis: Bolton, 1995b: 316. Junior synonym of tristis: Wilson, 2003: 769.

Description
From Wilson (2003): DIAGNOSIS A medium-sized reddish-yellow (major) or yellowish brown (minor) member of the tristis group whose major has very prominent subangulate pronotal humerus, swollen hind femora, diamond-shaped postpetiolar node with subangulate margins, small rounded subpostpetiolar process, and foveolate and opaque gastral tergite.

Minor: large ovoid postpetiolar node, prominent convex subpostpetiolar process, and foveolate and opaque gastral tergites. Similar to Pheidole balzani, Pheidole fabricator and Pheidole nigella, and less so to Pheidole brunnescens, Pheidole exarata, Pheidole excubitor, Pheidole germaini, Pheidole grandinodus, Pheidole hispaniolae, Pheidole obrima, Pheidole prattorum, Pheidole rogeri, Pheidole sabina, Pheidole sarpedon, Pheidole stulta, Pheidole tristops, Pheidole unicornis and Pheidole zoster, differing in many details of body form, sculpturing, and pilosity, as illustrated, and in color.

MEASUREMENTS (mm) Major (Boraceia Biological Station, Sao Paulo state): HW 1.66, HL 1.76, SL 0.82, EL 0.20, PW 0.84. Holotype minor: HW 0.80, HL 0.84, SL 0.84, EL 0.12, PW 0.52.

COLOR Major: body and appendages clear light reddish yellow ("orange"), with gaster a shade darker.

Minor: concolorous medium yellow brown, in both the Boraceia Biological Station series and holotype minor.



'''Figure. Upper: major (Boraceia Biological Station, Mun. Salesopolis, Sao Paulo state, Brazil, col. William L. Brown), associated with minors compared by E. O. Wilson with holotype minor from Tijuca, Rio de Janeiro, Brazil. At the bottom the right hind femur is depicted. Lower: holotype, minor. Scale bars = 1 mm.'''

Type Material
Tijuca, Brazil. - as reported in Wilson (2003)

Etymology
L tristis, sad, allusion unknown. (Wilson 2003)

References based on Global Ant Biodiversity Informatics

 * Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
 * Forel A. 1908. Ameisen aus Sao Paulo (Brasilien), Paraguay etc. gesammelt von Prof. Herm. v. Ihering, Dr. Lutz, Dr. Fiebrig, etc. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 58: 340-418.
 * Forel A. 1911. Ameisen des Herrn Prof. v. Ihering aus Brasilien (Sao Paulo usw.) nebst einigen anderen aus Südamerika und Afrika (Hym.). Deutsche Entomologische Zeitschrift 1911: 285-312.
 * Kempf W. W. 1965. Nota preliminar sôbre algumas formigas neotrópicas, descritas por Frederick Smith (Hymenoptera, Formicidae). Revista Brasileira de Biologia 25: 181-186.
 * Kempf W. W. 1978. A preliminary zoogeographical analysis of a regional ant fauna in Latin America. 114. Studia Entomologica 20: 43-62.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Luederwaldt H. 1918. Notas myrmecologicas. Rev. Mus. Paul. 10: 29-64.
 * Lutinski J. A., B. C. Lopes, and A. B. B.de Morais. 2013. Diversidade de formigas urbanas (Hymenoptera: Formicidae) de dez cidades do sul do Brasil. Biota Neotrop. 13(3): 332-342.
 * Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
 * Smith, Fr. "Catalogue of hymenopterous insects collected by Mr. A. R. Wallace in the Islands of Bachian, Kaisaa, Amboyna, Gilolo, and at Dory in New Guinea." Journal of the Proceedings of the Linnean Society of London, Zoology 5 (1860): 93-143.
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.