The Ants of West Africa & the Congo Basin

The Ants of Africa
Genus Strumigenys
Strumigenys ulugurensis Taylor new species - comparative description

Main species page

Bolton (1983: 379) considered S. londianensis and S. sarissa as closely related and readily separable from other Afrotropical Strumigenys species in having distinctive mandibular dentition, a deep preocular notch and a detached eye.

The only other species approximating to those features was S. bernardi but that has relatively long mandibles and lacks intercalary teeth in the apical fork. From the notes of Brown (1954k) on Congo Basin specimens, it seems also that this has small eyes and deep narrow preocular notches.

The comparative notes below are based on original descriptions and fresh specimens (the sarissa description being complemented by the Antweb.org photographs of the holotype).

S. londianensis	S. sarissa	S . ulugurensis	S. bernardi
TL 3.5-4.2 mm (Bolton) ca 3.0 mm (Patrizi)	TL 2.9-3.2 mm	TL 2.3 mm	TL 1.9-2.0 mm
HW 0.62-0.70, HL 0.84-0.92, CI 74-77	HW 0.50-0.60, HL 0.72-0.82, CI 68-75	HW 0.38, HL 0.50, CI 76	HW 0.36-0.41, HL 0.52-0.58, CI 67-72
ML 0.44-0.47, MI 51-52	ML 0.38-0.44, MI 53-55	ML 0.32, MI 54	ML 0.30-0.36, MI 55-65
Mandibles bowed but only weakly curved; without long hairs on the inner margin	Mandibles bowed but only weakly curved; with long hairs on the inner margin	Mandibles bowed and quite strongly curved; without long hairs on the inner margin	Mandibles bowed and quite strongly curved; without long hairs on the inner margin
SL 0.52-0.58, SI 82-87	SL 0.46-0.52, SI 83-92	SL 0.40 SI 95	SL 0.30-0.36, SI 82-92
Leading edge of scape with relatively few erect hairs some of which are curved basally	All hairs on leading edge of scape curved apically	All hairs on leading edge of scape curved apically	All hairs on leading edge of scape curved apically
Head in full face view with a moderately excavated occiput; scrobes without a well defined margin	Head in full face view with a shallowly excavated occiput; scrobes without abut well defined margin	Head in full face view with a deeply excavated occiput; scrobes with a narrow but well defined margin witha narrow dark lamina	Head in full face view with a shallowly excavated occiput; scrobes with awell defined margin but not lamina
Vertex of head in profile with a single pair of stout erect clavate hairs, other hairs all broadly spatulate	Vertex of head in profile without erect clavate hairs, other hairs all quite long and narrowly spatulate	Vertex of head in profile with a single pair of long narrow erect hairs, other hairs all narrow and semi-erect	Vertex of head in profile with 6 erect hairs, other hairs all narrowly spatulate
Alitrunk profile with pro-mesonotum domed and steeply stepped down to metanotal suture; propodeum dorsum shallowly convex	Alitrunk profile with pro-mesonotum convex; the mesonotum and propodeum forming a shallow concave arc	Alitrunk profile a smooth low arc not dropping sharply to metanotal suture; propodeum dorsum flat	Alitrunk profile with two shallow arcs; the mesonotum with a shallow step to a broadly defined but not impressed matanotal groove; posterior of mesonotum on same level as the shallowly convex propodeum dorsum
Pronotal humeri with stout straight hairs with clavate tips; similar pair of hairs on the mesonotum but no other erect hairs on alitrunk; altrunk sculpturation restricted to very fine almost effaced puncturations; pronotum with a distinct anterior and lateral margination, also a distinct median longitudianl carina	Pronotal humeri with elongate fine flagellate hairs; anterior margin of pronotum with a pair of shorter stouter erect hairs; altrunk sculpturation restricted effaced puncturations; pronotum without margination	Pronotal humeri with straight elongate quite thick hairs; pronotum with several other shorter erect hairs	Pronotal humeri with elongate fine flagellate hairs; other alitrunk pilosity small and appressed; altrunk sculpturation fairly coarsely puncturate with overlying longitudinal striation on the pronotum
Propodeum without triangular teeth (Tanzania specimens with short sharp teeth); laterally shiny but weakly punctate	Propodeum with blunt triangular teeth; laterally shiny unsculptured	Propodeum with triangular teeth; laterally shiny unsculptured	Propodeum with small triangular teeth; laterally shiny unsculptured
Postpetiole shiny, sub-ovoid, anterior margin narrower than the posterior margin; with a complete but very narrow posterior margin of spongiform tissue and a very small ventral spongiform lobe	Postpetiole dull, narrowly transversely ovoid; with a complete but very narrow posterior margin of spongiform tissue and a small ventral spongiform lobe	Postpetiole shiny, ovoid; with a complete but very narrow posterior margin of spongiform tissue and a small ventral spongiform lobe	Postpetiole dull, sub-rectangular; with a complete posterior margin of spongiform tissue and moderately large ventral spongiform lobe
Gaster very shiny, with basal costulae reduced to a line of very short markings; pilosity of a few quite long clavate hairs	Gaster moderately shiny, with basal costulae fine and dense; pilosity of a few quite long clavate hairs	Gaster very shiny, with basal costulae reduced to a line of very short markings; pilosity of a very few quite long quite slender straight hairs	Gaster moderately shiny, with basal costulae coarse and relatively long; pilosity of more abundant and shorter clavate hairs
Light brown, gaster darker	Light brown	Dark brown, gaster darker	Dull red-brown (Bolton has dull yellow)

Strumigenys ulugurensis new species

Type location Tanzania.

WORKER - TL 2.3 mm HL 0.50 HW 0.38 CI 76 MI 54 SL 0.38 SI 100; blackish-brown to black.

The photomontage is of four specimens collected from Tanzania; Uluguru Mts., western slope between Tchenzema village and Lukwangule Plateau, 2200m; V Grebennikov, 19-21.x.2002.

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