Avitomyrmex
| Avitomyrmex Temporal range: Ypresian, 51Ma | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Tribe: | †incertae sedis |
| Genus: | †Avitomyrmex Archibald, Cover, & Moreau, 2006 |
| Species | |
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see text | |
Avitomyrmex is an extinct genus of bulldog ants which contains three described species.[1] All three of the described species are from British Columbia, Canada.[1]
History and classification
Fossils of Avitomyrmex were first studied and described by Bruce Archibald, Stefan Cover and Corrie Moreau of the Museum of Comparative Zoology in Cambridge, Massachusetts. They published their 2006 description of the genus and species in an Annals of the Entomological Society of America journal article.[1] The genus name is a combination of the Latin "avitus" meaning "ancient" or "grandfatherly" and the Greek myrmex, meaning "ant".[1]
Included with the genus description, the paper contained the description of Avitomyrmex mastax, Avitomyrmex systenus, and the type species Avitomyrmex elongatus. [1]
Description
There are several characters which separate Avitomyrmex from other ant genera. The most notable feature is the distinctly slender nature of the queens and workers morphology. This is shown clearly in the shape of the waist connecting the thorax and the abdomen. While similar to the modern myrmeciin genus Nothomyrmecia of Southern Australia, the two genera are distinguishable by the structure of the petiole, with Avitomyrmex lacking the peduncle seen in Nothomyrmecia.[1]
A. elongatus
A. elongatus was described from a single side of a compression fossil found from the Middle Ypresian McAbee Fossil Beds, Kamloops Group, near Cache Creek, British Columbia.[1] The incomplete specimen, numbered 2003.2.8CDM032, is currently preserved in the paleontology collections housed at the Courtenay and District Museum, Courtenay, British Columbia. Archibald, Cover, and Moreau coined the specific epithet from the Latin "elongatus" meaning "prolonged" in reference to the elongated morphology of the type specimen. The species is discernible from the other two species of Avitomyrmex by its notably larger size, the preserved portion of the ant being over 20 millimetres (0.79 in). The holotype queen is preserved with a partly disarticulated gaster and is missing her head.[1]
A. mastax
The second species described from the McAbee Fossil Beds is A. mastax which, unlike A. elongatus, is known from a two specimens. The holotype and paratype are both included in the Thompson Rivers University, Kamloops, collections as UCCIPRL-18 F-850 and UCCIPRL-18 F-929 respectively.[1] The holotype specimen is a partial queen which is incomplete, with one fore-wing and the head fairly preserved, and the other isolated body portions indistinct. The paratype is a mostly complete queen missing parts of her gaster, legs and hind wings. Overall the species is estimated to have been 15 millimetres (0.59 in) long and has a fore-wing length of 13 millimetres (0.51 in). A. mastax is distinguishable from the other species in Avitomyrmex by its smaller mandible size and additionally the shape of the head capsule. The specific epithet mastax is from the Greek "mastax" meaning "jaw" or "mandible", a reference to the small size of the mandibles compared to the other species of Avitomyrmex.[1]
A. systenus
Of the three described species of Avitomyrmex found at the McAbee Fossil Beds, only A. systenus is known from worker caste specimens. The holotype is currently deposited in the Courtenay and District Museum paleontology collections as 2003.2.11 CDM 035 while the paratype, UCCIPR L-18 F-989, and an additional hypotype worker, UCCIPR L-18 F-825, which is tentatively assigned to the species are both deposited in Thompson Rivers University collections. Based on the mostly complete workers, mature specimens are estimated to have been 15 millimetres (0.59 in).[1] Due to the size of adult workers they cannot be attributed to A. elongatus, while the overall petiole, head capsule and mandible structure distinguish it from A. mastax. The shape of the head was the basis for Archibald, Cover and Moreau choosing the specific epithet systenus, which is from the Greek word systenos meaning "tapering to a point".
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 Archibald, S.B.; Cover, S. P.; Moreau, C. S. (2006). "Bulldog Ants of the Eocene Okanagan Highlands and History of the Subfamily (Hymenoptera: Formicidae: Myrmeciinae)" (PDF). Annals of the Entomological Society of America 99 (3): 487–523. doi:10.1603/0013-8746(2006)99[487:BAOTEO]2.0.CO;2.
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