Strumigenys scotti-group

Bolton, B., 2000, The ant tribe Dacetini. With a revision of the Strumigenys species of the Malgasy Region by Brian L. Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck., Memoirs of the American Entomological Institute 65, pp. 1-1028 : 670-672

scotti-group

DIAGNOSIS OF WORKER

Apical fork of mandible with 2 spiniform teeth; without intercalary dentition but rarely with 1 - 2 denticles located at the ventral base of the apicoventral tooth. Mandible with 2 stout or spiniform preapical teeth, situated in the apical third of the length; proximal preapical tooth slightly longer than the distal. Mandibles in full-face view and at full closure with outer margins shallowly and evenly convex to almost straight and parallel; in some species inner margin of mandible with a distinct lamella in (see species-complexes, below).

Scape elongate and cylindrical.

Ventrolateral margin of head without trace of a preocular notch, the margin continuous in front of the eye. Ventral surface of head without a preocular transverse groove but postbuccal groove is distinct.

Spongiform appendages of petiole usually developed into at least a narrow ventral curtain, rarely completely absent. Postpetiole usually with lateral and ventral lobes.

Pilosity. Pronotal humeral hair usually present, rarely absent. Upper scrobe margin with curved or appressed slender to clavate hairs (no hairs in diux ). Cephalic dorsum usually with 6 standing hairs, arranged as a transverse row of 4 near occipital margin and a pair close to highest point of vertex. Mesonotum with at least one pair of standing hairs. Dorsal surface of postpetiole, and gaster with short filiform to narrowly clavate hairs.

Sculpture. Head reticulate-punctate, rarely with longitudinal or oblique rugulae or costulae; alitrunk usually reticulate-punctate but pronotal dorsum occasionally smooth and / or with longitudinal costulae; pleurae usually smooth, rarely entirely reticulatepunctate. Gaster unsculptured except for basigastral costulae.

Glands. Scape gland absent ( balux , bola , chroa , glycon , ipsea , langrandi , lura , odacon , tegar ), or visible as an elongate patch near apex or rarely entire length of ventral scape ( cabira , covina , deverra , diota , diux , doxa , epulo , europs , finator , inatos , lexex, livens , lucomo , origo , ravola , rubigus , scotti ). Femoral gland bulla usually absent but present in cabira , covina , deverra , diota , epulo , inatos . Tibial gland bulla usually absent but present on at least the hind tibia in cabira , covina , deverra , epulo , langrandi , odacon . Gland at base of calcar conspicuous (absent in diota ). Tarsal gland bullae visible on at least first three tarsi of foreleg, decreasing in size from basitarsus where it is elongate to the third tarsal segment where it is oval. Mesopleural gland usually set in a circular notch, but in a concave impression in ipsea .

The absence of a preocular notch in the ventrolateral margin of the head and absence of a preocular transverse impression in the ventral surface of the head, combined with the presence of 2 stout preapical teeth on each mandible and elongate cylindrical to subcylindrical scapes, is immediately diagnostic of the scotti-group .

This group also contains 14 species in the Afrotropical region and two in the Malesian region. In the Malagasy region the group can be divided into 5 complexes, as follows.

1 chroa-complex ( balux , bola , cabira , chroa , covina , deverra , ipsea , tegar ). Mandibles in full-face view almost straight and at full closure parallel. Inner margin of mandible with a translucent lamina that extends from proximal preapical tooth, or close to tooth, to level of anterior clypeal margin (absent in ipsea ). Flagellate hairs usually absent (present at pronotal humeri in bola and deverra ). Dorsolateral margin of head posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape.

2 epulo-complex ( epulo ). Mandibles in full-face view with outer margins shallowly convex. Inner margin of mandible without a translucent lamina extending from vicinity of proximal preapical tooth to level of anterior clypeal margin. Cephalic dorsum, pronotum, mesonotum, petiole and postpetiole with standing fine, flagellate hairs. Dorsolateral margin of head posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape.

3 diux-complex ( diux , doxa ). Mandibles in full-face view with outer margins shallowly convex. Inner margin of mandible without a translucent lamina extending from vicinity of proximal preapical tooth to level of anterior clypeal margin. Flagellate hairs absent. Pronotal humeral hair stiff, filiform. Dorsolateral margin of head posteriorly with 1 or more stiff erect hairs that are longer than hairs on leading edge of scape.

4 diota-complex ( diota ). Mandibles in full-face view with outer margins very shallowly convex. Inner margin of mandible without a translucent lamina extending from vicinity of proximal preapical tooth to level of anterior clypeal margin. Flagellate hairs absent. Pronotal humeral hair absent. Dorsolateral margin of head posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape.

5 scotti-complex ( europs , finator , glycon , inatos , langrandi , levex, livens , lucomo , lura , odacon , origo , ravola , rubigus , scotti ). Mandibles in full-face view with outer margins shallowly convex. Inner margin of mandible without a translucent lamina extending from vicinity of proximal preapical tooth to level of anterior clypeal margin. Pronotal humeral hair flagellate. Dorsolatereal margin of head posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape.