Octostruma triquetrilabrum

Octostruma triquetrilabrum is known from two sites near Monteverde in the Cordillera de Tilarán, and one site in the mountains of western Panama. One Monteverde site is very wet, old-growth montane forest at 800 m on the Atlantic slope, and the other Monteverde site is a small patch of seasonal moist forest at 1150 m, just below the cloud forest on the Pacific slope. All specimens are from Winkler samples of sifted leaf litter. (Longino 2013)

Identification
With the characters of Octostruma wheeleri and Octostruma triangulabrum. Differing from O. wheeleri in the presence of 8-10 spatulate setae on face (6 on O. wheeleri) and shallow reticulate rugulose sculpture on face and dorsal pronotum (nearly smooth on O. wheeleri). Differing from O. triangulabrum in the absence of a pair of spatulate setae on the mesonotum (present in O. triangulabrum); first gastral sternite more uniformly punctate. (Longino 2013)

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Panama.

Castes
Known only from the worker caste.

Nomenclature

 *  triquetrilabrum. Octostruma triquetrilabrum Longino, 2013: 53, figs. 1A, 3A, 5K, 39, 43 (w.) COSTA RICA.

Worker
HW 0.74–0.80, HL 0.68–0.72, WL 0.84–0.88, CI 109–111 (n=2). Matching in almost every respect the description for Octostruma triangulabrum, except the differences outlined in the Diagnosis and key.

Type Material
Holotype worker: COSTA RICA, Puntarenas: Est. Biol. Los Llanos, near Santa Elena, 10.30487, -84.83735, ±100 m, 1150 m, 28 Feb 2004, moist forest, ex sifted leaf litter (J. Longino#5249-s), JTLC000004551. Paratype workers: same data, JTLC000004543; same data except Alajuela: Casa Eladio, Rio Peñas Blancas, 10.31667, -84.71667, ±2 km, 800 m, 10 May 1989, wet forest, ex sifted leaf litter on ground (J. Longino#2529-s) , INBIOCRI001281407; 23 May 1990 (J. Longino#2701-s) , CASENT0627377; , CASENT0627378; , INBIOCRI001282521; , INBIOCRI001282522; CASC, INBIOCRI001282523.

Etymology
The name refers to the triangular labrum that is not bilobed at the apex. It is a noun in apposition and thus invariant.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. 2013. A revision of the ant genus Octostruma Forel 1912 (Hymenoptera, Formicidae). Zootaxa 3699(1): 1-61.
 * Ulyssea M. A., L. P. Prado, C. R. F. Brandao. 2015. Type specimens of the traditional Myrmicinae (Hymenoptera: Formicidae) ant tribes deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil: Adelomyrmecini, Basicerotini, Blepharidattini, Crematogastrini, Formicoxenini, Lenomyrmecini, Myrmicini, Phalacromyrmecini, Pheidolini, Stegomyrmecini, Stenammini and Tetramoriini. Papeis Avulsos de Zoologia, Museu de Zoologia da Universidade de Sao Paulo 55(12): 175-204.