Pheidole scalaris

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Pheidole scalaris
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole
Species: P. scalaris
Binomial name
Pheidole scalaris
Wilson, 2003

Pheidole scalaris inbiocri002279609 p 1 high.jpg

Specimen Labels

Longino (1997) found P. scalaris in both seasonal dry forest and evergreen forest. The workers were recruited to baits on the forest floor.


See the description in the nomenclature section.

Keys including this Species


Atlantic and northern Pacific lowlands of Costa Rica; and Arima Valley, Trinidad. (Wilson 2003)

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality), Ecuador, Nicaragua, Trinidad and Tobago, Venezuela.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb






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

  • scalaris. Pheidole scalaris Wilson, 2003: 643, figs. (s.w.) COSTA RICA.

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


DIAGNOSIS Close to Pheidole transversostriata but distinguished from it and other members of the transversostriata group by the broad occipital zone of rugoreticulum on the dorsal surface of the head of the major, surmounting a wide “ladder” of parallel transverse carinulae that reach the frontal lobes, where they curve anteriorly to the ends of the lobes; also, the promesonotal dorsum is completely covered by transverse carinulae. Also, see the distinctive color of the minor (below).

This species is possibly synonymous with P. transversostriata var. nigridens Forel of Colombia, which has been provisionally synonymized with transversostriata; nigridens has rugoreticula on the occipital corners and more carinulae on the pronotal dorsum, and is intermediate between Pheidole scalaris and transversostriata. However, scalaris also differs from transversostriata by the more elongate head of the major (Head Length 1.3! Head Width versus 1.2X in transversostriata) and smooth sides of the pronotum of the minor.

MEASUREMENTS (mm) Holotype major: HW 0.64, HL 0.84, SL 0.32, EL 0.10, PW 0.36. Paratype minor: HW 0.42, HL 0.46, SL 0.36, EL 0.08, PW 0.26.

COLOR Major: concolorous medium yellow.

Minor: overall light brownish yellow, with medium brown vertex, occiput, and dorsum of promesonotum, and medium yellow appendages.

Pheidole scalaris Wilson 2003.jpg

Figure. Upper: holotype, major. Lower: paratype, minor. Scale bars = 1 mm.

Type Material

COSTA RICA: La Selva Biological Station, near Puerto Viejo, Heredia, col. Stefan Cover. Museum of Comparative Zoology


L scalaris, of a ladder, alluding to the strong ladder-like pattern on the dorsum of the major head.