Simopone oculata

The type was collected in secondary tropical forest under a wood stump.

Identification
A member of the grandidieri species group. This appears to be a more slender species, with AIIW/AIIL 0.80. Like Simopone chapmani and Simopone gressitti, AII is longer than AIII and the metapleuron has a transverse sulcus. However, Radchenko’s figs 4 and 5 show a lack of the defined antennal scrobe, deflected down in front of the eye, that is characteristic of those two species. In fact, the morphology of this area of the head seems more closely to resemble that of the Malagasy species Simopone elegans and Simopone grandidieri, where the impression between antennal socket and anterior margin of eye is a broad but shallow fossa, rather than a defined longitudinal scrobe. (Bolton and Fisher 2012)

Distribution based on Regional Taxon Lists
Oriental Region: Thailand, Vietnam.

Nomenclature

 * . Simopone oculata Radchenko, 1993b: 45, figs. 4-6 (w.) VIETNAM (Kondor I.).
 * Type-material: holotype worker.
 * Type-locality: Vietnam: Kondor I. (= Côn Đáo), N 127-87, 5.iv.1987 (A. Radchenko).
 * Type-depository: SIZK.
 * Status as species: Bolton, 1995b: 383; Bolton & Fisher, 2012: 71; Chen, Zhou & Liang, 2015: 9 (in key); Chen, Chen & Zhou, 2019: 30 (in key).
 * Distribution: Vietnam.

Worker
Dimensions (in mm). Holotype worker: AL 1.02; HL 0.84; HW 0.55; ED 0.38; OD 0.27; PTW 0.45; PTL 0.56; PPTW 0.50; PPTL 0.53; PW 0.45; TL 4.5.

Head elongate (CI 65); sides almost parallel, slightly concave before eyes, slightly convex behind; occipital border feebly concave; occipital carinae well developed, enclosing the occiput laterally as well as dorsally. Eyes very large (OI 69), interocular distance very short (IOI 0.71); Ocelli minute. Scapes barely reaching anterior margin of eyes. Median portion of anterior clypeal border slightly convex. Frontal carinae feebly curved, not diverging posteriorly, meeting very fine postorbital carina. Alitrunk twice as long as broad in dorsal view, its dorsolateral borders right-angled, carinate on the pro- and mesosotum as well as posterior border of propodeum; anterior border of propodeum with strongly developed transverse carina. Promesonotal suture represented by transversely ribbed trace on alitrunk dorsum, mesopropodeal suture feebly developed, poorly visible; both sutures well developed on the sides of the alitrunk. Femora and tibiae moderately inflated. Petiole in dorsal view broader behind than in front, with a distinct transverse anterior carina, IPT 1.25; lateral and posterior borders not carinate; posterior border concave medially. Postpetiole subsquare (IPPT 1.06) with parallel sides and rounded anteroventral and posteroventral corners; its posterior border with transverse carina. Mandibles and entire body smooth and shining, lacking sculpturation except for scattered minute piligerous punctures. Dorsum of head and alitrunk and entirely petiole, postpetiole and gaster with very short, sparse decumbent or subdecumbent pilosity, distance between pilosulae longer than their length. Erect hairs rare. Colour dark brown, almost black; mandibles, appendages and apex of gaster reddish-brown.

Type Material
Bolton and Fisher (2012) - Holotype worker, Vietnam: Isl. Kondor, N. 127-87, 5.iv.1987 (A. Radchenko) [not seen].

References based on Global Ant Biodiversity Informatics

 * Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
 * Chen Z., Y. Chen Y, and S. Zhou. 2019. Simopone fisheri sp. n., a new species of Dorylinae ants (Hymenoptera, Formicidae) from China, with an illustrated key to the S. grandidieri-group species. ZooKeys 838: 21–33.