Pheidole transversostriata

Forel (1901) collected this species from soil in Colombia (Wilson 2003). Longino (1997) found it in both seasonal dry forest and evergreen forest. The workers were recruited to baits on the forest floor.

Identification
See the description in the nomenclature section.

Distribution
P. transversostriata is evidently a wide-ranging but locally uncommon species, known from scattered records from St. Thomas, Virgin Islands, and Trinidad and Tobago (Port of Spain, Arima Valley) to the Guianas, Colombia, and Rio de Janeiro and Santa Catarina, Brazil and the Atlantic and northern Pacific lowlands of Costa Rica. (Wilson 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Barbados, Brazil, Colombia, Costa Rica, Ecuador, Guyana , Nicaragua, Suriname, Trinidad and Tobago, Venezuela.

Worker
Minor

Nomenclature

 *  transversostriata. Pheidole transversostriata Mayr, 1887: 584 (s.) GUYANA.
 * Senior synonym of lacerta, nigridens: Wilson, 2003: 645.
 * Senior synonym of scalaris: Longino, 2019: 62.
 * nigridens. Pheidole transversostriata var. nigridens Forel, 1901e: 362 (s.w.) COLOMBIA.
 * Junior synonym of transversostriata: Wilson, 2003: 645.
 * lacerta. Pheidole lacerta Wheeler, W.M. 1922c: 6 (s.) TRINIDAD.
 * Junior synonym of transversostriata: Wilson, 2003: 645.
 * scalaris. Pheidole scalaris Wilson, 2003: 643, figs. (s.w.) COSTA RICA.
 * Junior synonym of transversostriata: Longino, 2019: 62.

Taxonomic Notes
Wilson (2003) surmised that P. scalaris could be a synonym of P. transversostriata. The two were separated by minor differences in sculpture on the minor worker and head shape of the major worker. So far there is no evidence of sympatry of separate forms. The distinctive major workers identify a widespread clade, and at this stage there is little value in using separate names for local variants.

Description
From Wilson (2003): DIAGNOSIS A member of the transversostriata group distinguished in the major by the broad ladder-like array of transverse carinae that extend unbroken from the occiput to the frontal lobes where they curve anteriorly to the ends of the lobes. It is close to scalaris of Costa Rica, differing in the major in the lack of rugoreticulum on the occiput (completely reticulate in scalaris) and less elongate head (Head Length 1.2! Head Width versus Head Length 1.3! Head Width in scalaris), and in the minor by the completely foveolate sides of the pronotum (versus smooth and shiny in scalaris). However, a major syntype of transversostriata “var. nigridens” from Colombia has the corners of the occiput rugoreticulate and is thus intermediate between transversostriata and scalaris in this character. The two forms may prove to be geographic variants (or good species) when more material becomes available.

MEASUREMENTS (mm) Unique holotype major: HW 0.66, HL 0.80, SL 0.34, EL 0.10, PW 0.36. Minor (St. Thomas, Virgin Islands): HW 0.40, HL 0.44, SL 0.36, EL 0.06, PW 0.26.

COLOR Major: medium yellowish brown, with head a shade lighter and gaster a shade darker than mesosoma and waist.

Minor: concolorous yellowish brown, legs clear yellow.

Pheidole transversostriata

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 transversostriata''. Upper: major (syntype of synonymous P. lacerta Wheeler, Port of Spain, Trinidad, compared with unique holotype of P. transversostriata). Lower: minor (Inner Brass, St. Thomas, Virgin Islands, associated with major compared with transversostriata holotype). Scale bars = 1 mm.'''



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

Type Material
Guianas. - as reported in Wilson (2003)

Pheidole scalaris: COSTA RICA: La Selva Biological Station, near Puerto Viejo, Heredia, col. Stefan Cover.

Etymology
L transversostriata, transversely lined, referring to the transverse carinulae of the major head. (Wilson 2003)

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