Friday, September 8, 2017

[PaleoEntomology • 2017] Linguamyrmex vladi • A New Genus of Hell Ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with A Novel Head Structure


 Linguamyrmex vladi Barden & Grimaldi, 2017

  
Abstract

An unusual Cretaceous trap jaw ant is described from Burmese amber dated to the Late Cretaceous. Linguamyrmex vladi gen.n. sp.n. is distinguished by an unusual suite of morphological characters indicating specialized predatory behaviour and an adaptive strategy no longer found among modern ant lineages. The clypeus, highly modified as in other closely related haidomyrmecine hell ants, is equipped with a paddle-like projection similar to Ceratomyrmex. X-ray imaging reveals that this clypeal paddle is reinforced, most probably with sequestered metals. Presumably this fortified clypeal structure was utilized in tandem with scythe-like mandibles to pin and potentially puncture soft-bodied prey. This unique taxon, which stresses the diversity of stem-group ants, is discussed in the context of modern and other Cretaceous trap jaw ant species.



Description
Order Hymenoptera Linnaeus, 1758
Family Formicidae Latreille, 1809
Tribe Haidomyrmecini Bolton, 2003

Genus Linguamyrmex Barden & Grimaldi, new genus

Diagnosis, workerAs in other haidomyrmecines (Haidomyrmex, Haidoterminus, Haidomyrmodes, Ceratomyrmex), head hypognathous-like with mandibles projecting primarily downward; mandible scythe-like, with flattened basal margin leading to a curved apical tooth that is expanded perpendicular to axial plane of head. Cephalic clypeal ‘horn’ present but abbreviated, differs from Ceratomyrmex by horn stalk of Linguamyrmex being glabrous, that of Ceratomyrmex with fine, stiff setae of various lengths; clypeal horn much shorter in Linguamyrmex, less than head length/depth, stalk short, with the expanded, flat, paddle-shaped setose pad comprising >50% total horn length; clypeal pad slightly trough-shaped ventrally, covered with very short, dense velcro-like vestiture; trigger hairs originate not at base of stalk as in Ceratomyrmex but near basal margin of setose pad; ocelli present. In addition, Linguamyrmex with first and second gastral segments with deep constriction between them (a gastral constriction is figured in description of Haidomyrmodes mammuthus but is less developed).

Type species: L. vladi sp.n.

Etymology: From Latin ‘lingua’, meaning tongue – in reference to the tongue-like clypeal projection – and the Greek ‘myrmex’, meaning ant.

Linguamyrmex vladi Barden & Grimaldi sp.n.


Etymology: In reference to Vlad III, or Vlad Dracula (c. 1429–1476), prince of a region of Romania then called Wallachia. His moniker, Vlad the Impaler, refers to his favoured and frequent method of execution, which inspired the vampirous character Count Dracula fictionalized by Bram Stoker in 1897. The patronym is in reference to the presumed impalement of prey by Linguamyrmex and its liquid diet (see later).

....


Phillip Barden, Hollister W. Herhold and David A. Grimaldi. 2017. A New Genus of Hell Ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with A Novel Head Structure. Systematic Entomology. 42(4); 837–846.  DOI: 10.1111/syen.12253