.jpg){kind=logo}
Strumigenys mirabilis group
Strumigenys mirabilis group Bolton (2000)
Species
Neotropical
Worker Diagnosis
Mandibles in full-face view and at full closure narrowly triangular, the serially denticulate masticatory margins engage throughout their visible lengths. In profile dorsal surface of mandible shallowly convex, down-curved only near apex; blade broadest near midlength, narrowing where it passes beneath the clypeus, broadening again near the basal articulation. In ventral view outer margin of mandible without an inflected prebasal angle. MI 20-21.
Dentition. Masticatory margin with a continuous crowded row of tiny teeth that follow the basal lamella without a diastema; basal 7-9 appear the largest; without series of enlarged teeth basally nor with isolated enlarged teeth or groups of taller teeth anywhere on the margin. Distal of tooth 9 with apparently 8-9 denticles and a somewhat larger apical tooth to give a total dental count of about 17-19.
Basal lamella of mandible an elongate low lobe that terminates anteriorly at the basal tooth; lamella no taller than basal series of teeth. In full-face view basal lamella projects beyond anterior clypeal margin when mandibles fully closed; more proximal portions visible through translucent lamina that forms anterior portion of clypeus.
Labrum terminates in a pair of triangular to conical lobes.
Clypeus with anterior margin evenly shallowly convex, the lateral margins feebly divergent posteriorly. Anterior and lateral margins are lamellate and translucent; measured along the midlength of the clypeus the anterior lamellate zone accounts for about one-fifth the clypeal length. In full-face view outer margins of mandibles basally are only just covered by the lateral margins of the clypeus.
Clypeal dorsum with anteriorly curved spatulate hairs that are slightly elevated, not appressed. Lateral margins of clypeus with a fringe of anteriorly curved projecting spatulate hairs.
Preocular carinae clearly visible in full-face view, in lateroventral view seen to taper posteriorly and extend back as far as the eye. Dorsolateral margin of head bordered with a broad subspongiform lamina.
Ventrolateral margin of head between eye and mandible with side curving shallowly into ventre, not marginate but shallowly convex from preocular carina to ventral surface. Postbuccal impression conspicuous.
Cuticle of side of head within scrobe smooth and shining. Posteroventral margin of scobe, behind eye, with a subspongiform lamina that meets the lamina of the upper scrobe margin posteriorly in an acute internal angle.
Scape moderate, SI 76-84, slender, slightly dorsoventrally flattened; with a sharp leading edge, weakly flattened ventral surface, and lacking a pronounced subbasal angle.
Funicular segments 2 and 3 much longer than broad.
Leading edge of scape with a row of elongate and quite narrowly spatulate hairs that are all curved toward the apex of the scape.
Propodeum bordered by cuticular lamellae both dorsally and on declivity. A poorly defined curved spine-vestige is entirely embedded in the lamella, beyond its base the spine is detectable only as a slightly more densely sclerotised dark strip within the lamella. Propodea1 spiracle on extreme posterior margin of declivity.
Spongiform appendages. Petiole with a deep ventral curtain and peduncle also with a dorsal lamella. Lateral lobes of petiole and postpetiole, and ventral lobe of the latter, large and conspicuous. First gastral sternite in profile with a dense spongiform pad basally.
Pilosity. Pronotal humeral hair very long, fine and flagellate. Dorsal surfaces of head and promesonotum with numerous curved elongate spatulate hairs and longer curved hairs that are flattened and blunt apically. Elongate spatulate hairs also numerous on ventre of head. Apicoscrobal hair very long, fine and flagellate. Dorsum of head with a single pair of erect flagellate hairs that arise from about the highest point of the vertex. Mesonotum with a single pair of flagellate hairs; waist segments and first gastral tergite with numerous fine flagellate hairs. Legs with curved spatulate hairs that are somewhat elevated, but without freely projecting hairs.
Notes
The single species classified here, Strumigenys mirabilis, is remarkable for its development of lamellate cuticular outgrowths on many surfaces of the head and body. These were the main features used to characterise it as a separate genus-rank taxon, Tingimyrmex, now abandoned (Bolton, 1999). I strongly suspect that the lamellae, striking though they may be, are likely to be restricted to this one species and not be useful as diagnostics at species-group level. It is certain that the lamellae are so immediately obvious that they distract the attention from other important features. For this reason they are only mentioned in the group diagnosis above but are described in more detail in the species description.
References
- Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History. 33:1639-1689.
- Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.