Acanthognathus stipulosus

An uncommon ant taken from leaf litter.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Biology
Holotype (MCZ) a unique taken in rain forest near the quarry at the high falls (Cachoeira Alta) of a branch of the Rio TarumS, northeast of Manaus, Amazonas, Brasil; 28 August 1962, W. L. Brown, Jr., leg. The worker was taken from a leaf litter berlesate. This is the first record of the genus from the middle Amazonian region. It must be uncommon, for it was taken only once out of many Berlese funnel extractions from the Manaus area.

Nomenclature

 *  stipulosus. Acanthognathus stipulosus Brown & Kempf, 1969: 104, fig. 3 (w.) BRAZIL. See also: Bolton, 2000: 17.

Description
Measurements and indices given m Table I. A small-sized, slender species resembling A. ocellatus and A. brevi­cornis. The character that immediately sets this species off from the rest is the shape of its petiole ( Fig. 3). Set on a long, gently curved peduncle, the node is compressed anteroventrally, and is sharply rounded above in side-view profile. Seen from above,  the anterior peduncle  is  about  3Yz  times  as  long  as  the  node,  and  the  posterior peduncle about half as long ; the node itself is about o.IO mm long and 0.18 mm wide,  with a convex  anterior face and a flat, sloping posterior face ; the anterior peduncle widens gradually behind the spiracles to receive the node. Seen from behind, the node is some­what like a Formica petiole in outline, with broadly rounded crest, bulging sides and narrower ventral  portion. Postpetiole about  0.16 mm long, 0.17 mm wide, subcircular as seen from above, with straight anterior  margin. Also the following characters : ( l ) Mandibles relatively shorter than in ocellatus, their preapical borders unarmed except for an almost imperceptible "submedian welt." (2)	Humeral teeth triangular, strongly projecting, rendering the promesonotum very  slightly broader  than  long  ( cervix  excluded ). Sculpture of promesonotum consisting of about 8 slightly wavy costulae running anteriad from the metanotal groove and fanning out to meet 2-3 short transverse costulae on the anterior pronotum ; costulae and interspaces  shining; cervix smooth and shining. (3)	Propodeal dorsum gently convex, smooth and shining discad ; spines long  and  nearly  straight as  seen  from  side,  but  slightly  di­ vergent with apices incurved as seen from above ; moderately elevated. ( 4) Head smooth and shining, with spaced but large and distinct round fossae over the dorsum, each centrally tuberculate and bearing an inclined, short, white clavate hair. Sides of alitrunk loosely rugose, shining; rest  of  body  and  most  parts  of  appendages  smooth  and shining. ( 5 ) Color reddish ferruginous, gaster darker, reddish-brown ; legs, mandibles and antennae pale straw yellow, middle and posterior femora each with a broad subapical brownish band. a unique taken in rain forest near the quarry at the high falls ( Cachoeira Alta ) of a branch of the Rio Tamma, northeast of  Manaus, Amazonas,  Brasil ; 28 August  1962, W. L. Brown, Jr., leg. The worker was taken from a leaf litter berlesate.
 * Holotype worker :
 * Holotype ( MCZ )