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Emplastus amguensis
| †Emplastus amguensis Temporal range: Rupelian, Oligocene Amgu River, Primorye, Russia | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Subfamily: | Dolichoderinae |
| Genus: | Emplastus |
| Species: | †E. amguensis |
| Binomial name | |
| †Emplastus amguensis Perfilieva, 2022 | |
Described from a Lower Oligocene wing imprint of the Kizi Formation.
Identification
A triangular radiomedial cell without stem is present in three species of this genus: Emplastus kozlovi (FWL 7.8–8.8 mm in males), Emplastus haueri (FWL 5.4 mm), and Emplastus miocenicus (FWL 10.1 mm). The latter, in addition to its significantly larger size, differs from the new species in the rectangular shape of the mediocubital cell. Emplastus haueri has a relatively short 3r cell and a smaller wing size. The greatest similarity is observed with Emplastus kozlovi from the Eocene marls of Bembridge, but the relatively longer mediocubital cell in E. amguensis (I(mcu) 0.7 and 0.5, respectively) has a different length ratio of 1M and m-cu. The wing sizes in the three species of this genus from Bolshaya Svetlovodnaya are somewhat smaller than in this species (Dlussky et al., 2015).
Wing venation indicates affiliation to Dolichoderinae. Although individually the features of venation in E. amguensis and E. kozlovi are found in extant representatives of several genera of Dolichoderinae, a certain combination of venation features in these imprints is unique (triangular rm, absence of 4RS, trapezoid mcu, and the ratio of 1M and m-cu, I(mcu)). Some extant Tapinoma have the most similar venation (e.g., specimen CASENT0109245, online catalog AntWeb.org), but, at the same time, a different shape of the mediocubital cell and a lower radial cell index (Ir = 0.5). There is also a strong similarity to the wing of the Aneuretinae; however, as noted above, in the absence of a body imprint, I do not consider this variant.
Distribution
This taxon was described from Amgu River, Primorye, Russia (Rupelian, Oligocene).
Castes
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Also see Perfilieva 2022. Plate 10, Figure 1.
Nomenclature
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- †amguensis. †Emplastus amguensis Perfilieva, 2022: 415, fig. Plate 10, fig. 1 (q.) RUSSIA (Oligocene).
Description
FWL ~ 7.0. FWPt = 3.5, 3r cell length = 2, rm cell length = 1.1. The pterostigma is elongated. The radiomedial cell is triangular without a pronounced 2M section, without a stem, or the stem is as short as possible, almost not expressed; the cell length-to-width ratio is approximately 2.5. Crossveins 2r-rs and rs-m are on the same line. Medium-sized mediocubital cell is trapezoid, m-cu and 1M are almost of the same length (m-cu > 1M 1.1 times), 1Cu is 1.3 times as long as RS + M. The mcu cell is elongated, its distal end does not reach the level of the pterostigma. The second cubitanal cell is not formed. The ratio of the lengths of the radial cells Ir = 0.8.Icu ~ 1.5, Icua ~ 1.3, I(mcu) ~ 0.5.
Type Material
- Holotype. PIN, no. 3135/1, forewing imprint; Primorsky Krai, Tatar Strait, Terney District, right bank of the Kudya River, a tributary of the Amgu River; Lower Oligocene, Granatnenskaya Formation.
Etymology
From the location of the imprint at the Amgu River.