Pheidole bajaensis, Wilson, E. O., 2003

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 559

Pheidole bajaensis new species

types Mus. Comp. Zool. Harvard.

etymology L bajaensis , named after the Mexican state of origin.

Diagnosis Close to and possibly conspecific with yaqui , differing as follows.

Major: occiput rugulose from the midline partly out to the occipital corners; postpetiole laterally subangulate seen from above; margins of anterior half of pronotum not transversely carinulate.

Minor: humerus in dorsal-oblique view less angulate and occipital lobes in full-face view more so, and propodeal spines longer. Together, bajaensis and yaqui differ from gilvescens and xerophila in the major's head shape, which in side view is rounded (not flattened) in the dorsal profile of its posterior half, and the failure of the head to taper toward the occiput; other traits exist in major and minor as shown. Philip Ward (personal communication) has pointed out thai yaqui and bajaensis are joined by intermediates in the degree of occipital regulation, forming what appears to be a southward cline on Baja. He recommends treating the two forms as one species. Ward may be right, but I have hesitated to unite the two forms in view of the presence of other defining traits described here in the Diagnosis.

Measurements (mm) Holotype major: HW 1.22, HL 1.26, SL 0.64, EL 0.24, PW 0.52. Paratype minor: HW 0.54, HL 0.60, SL 0.52, EL 0.20, PW 0.32.

color Major: body and appendages medium yellow except mandibles, which are dark yellow. Minor: body and appendages medium yellow.

Range Known only from Baja California Sur; possibly a geographic variant of yaqui , as noted in the Diagnosis above.

Biology Unknown.

Figure Upper: holotype, major. Lower: paratype, minor. BAJA CALIFORNIA SUR, MEXICO: 50 km south-southwest of San Ignacio, 26°52'N 113°08W (Philip S. Ward). Scale bars = 1 mm.