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Zigrasimecia thate
| †Zigrasimecia thate Temporal range: Early Cenomanian, Late Cretaceous Burmese amber, Kachin State, Myanmar | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Subfamily: | Zigrasimeciinae |
| Genus: | Zigrasimecia |
| Species: | †Z. thate |
| Binomial name | |
| †Zigrasimecia thate Chaul, 2023 | |
Photo Gallery
Chaul (2023), Fig. 13. Holotype of Zigrasimecia thate (ANTWEB1038912). A, full-face view of the head, black triangles indicate mandible dorsal setae; B, profile view of left side of body; C, anterior view of the head ; D, dorsal view of the body; E, zoom of flagelliform setae on frons and vertex (same view as C); F, detail of mesosomal profile. Abbreviations: Lmspl, lower mesopleuron; Lmtpl, lower metapleuron; mgo, metapleural gland opening; Ppd, propodeum; Prn, pronotum; sp, spiracles (metanotal and propodeal); Umspl, upper mesopleuron. Scale bars are 0.2 mm in B and D, and 0.1 mm in A.
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Identification
Small species. Head subquadrate in full-face view. Standing setae on body almost entirely absent, except for a patch of long, subflagellate or hook-shaped setae on the frontovertexal region. Small compound eyes. Dorsal mesosomal outline mildly convex; propodeum strongly angled between the dorsal and posterior surfaces. Petiolar node not forming a distinct dorsal surface, the transition from the anterior to the posterior surfaces being a short, curved surface in lateral view; apex of node transversally mildly bilobed.
The subflagellate setae on the frontovertexal area are immediately diagnostic of Z. thate. The hook-shaped appearance of the setae could be thought of as preservational, formed by the resistance the resin while the ant was trapped, but since all the setae on the right side are curved opposite to those on the left side, the condition is thus interpreted as a true feature of the species. Zigrasimecia ufv-11, discussed below, have similarly curved setae on the dorsum of head, however, in that morphospecies, the setae are much smaller, appressed, and appear to be thicker.
The pair of setae on the dorsal surfaces of the mandibles (Fig. 13, A, black triangles) is clearly seen in Zigrasimecia perrichoti and Zigrasimecia ufv-11, and might well be common to all Zigrasimecia species although not detected in most specimens due to the difficulties to prospect information inherent of amber specimens.
Keys including this Species
Distribution
This taxon was described from Burmese amber, Kachin State, Myanmar (Early Cenomanian, Late Cretaceous).
Castes
Nomenclature
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- †thate. †Zigrasimecia thate Chaul, 2023: 323, fig. 13 (w.) MYANMAR (Burmese Amber, Cretaceous).
Type Material
- Holotype worker (ANTWEB1038912). Hukawng Valley, Kachin Province, Myanmar; Lower Cenomanian (ca.98.79 ± 0.62 Ma) [CELC].
The specimen has little or no distortion or stretching, the cuticle is not damaged or desiccated. The matrix is very clear, but has a fracture that crosses the specimen from side to side, passing in the head at mid-height, in the legs more or less at the tibial level (on the left side), and across the gaster. The fracture does not interfere substantially on the visualization of the ant.