Linguamyrmex Barden & Grimaldi, 2017

Phillip Barden, Hollister W. Herhold & David A. Grimaldi, 2017, A new genus of hell ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with a novel head structure, Systematic Entomology 42, pp. 837-846 : 839

Genus Linguamyrmex Barden & Grimaldi , new genus

http://zoobank.org/urn:lsid:zoobank.org:act:9F04FAEE-59DA- 4B3C-AB8B-EE0D234CC118

Figs 1–5 , 7 , Video S1.

Diagnosis, worker. As 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.

Figures

Fig. 1. Photomicrographs of Linguamyrmex vladi. (A) Lateral habitus view of holotype specimen BuPH- 01. (B) View of head capsule and mesosoma. Scale bars, 0.5 mm. [Colour figure can be viewed at wileyonlinelibrary. com].

Fig. 2. Photomicrographs of Linguamyrmex vladi and Linguamyrmex sp. (A) Alternate lateral view of L. vladi holotype specimen BuPH- 01. (B) Lateral head view of specimen BuPH- 03, Linguamyrmex sp.; note that the specimen is heavily desiccated (alternate view in Fig. 4). (C) Posterolateral view of Linguamyrmex sp. specimen BuPH- 04. (D) Linguamyrmex sp. specimen BuPH- 02; much of the specimen is rendered invisible due to a large fissure and calcite infiltration (also rendered in Video S 1). Scale bars, 1 mm. [Colour figure can be viewed at wileyonlinelibrary. com].

Fig. 3. Illustration of Linguamyrmex vladi and Linguamyrmex sp. (A) BuPH- 04 lateral habitus. (B) Dorsal view of setose clypeal paddle, specimen BuPH- 04. (C) Lateral view of specimen BuPH- 02 mandible. (D) Lateral view of specimen BuPH- 03 mandible (E) Enlarged view of BuPH- 03 mandible (F) Linguamyrmex vladi holotype BuPH- 01 lateral habitus. (G) Dorsal view of frontal triangle and clypeal paddle of specimen BuPH- 01. (H) Apex of apical tooth of specimen BuPH- 01. (I) Basal margin of mandibles, which corresponds with origin of apical tooth. Scale bars, 0.1 mm.

Fig. 4. Photomicrograph and illustration of Linguamyrmex sp. Specimen BuPH- 03. (A) Photomicrograph in lateral view of Linguamyrmex sp. and beetle larvae. Scale bar, 1.0 mm. (B) Rendering of specimen BuPH- 03. [Colour figure can be viewed at wileyonlinelibrary. com].

Fig. 5. Three-dimensional reconstruction and two-dimensional X-ray ‘ slices’ of Linguamyrmex vladi. (A) Three-dimensional reconstruction of specimen BuPH- 01 in lateral view. Some elements are irrecoverable in X-ray imaging due to the similar attenuation properties of both amber and thin cuticle. Scale bar, 0.75 mm. (B) Lateral view of head capsule, mandibles and clypeal paddle. Planes C and D correspond with panels C and D, respectively. Scale bar, 0.2 mm. (C) Cross-section of clypeal paddle from oblique dorsal view. Labels demonstrate approximate pixel ‘ grey values’ for each fossil material, which in turn represent relative X-ray attenuation levels. (D) Cross-section of clypeal paddle from frontal view. Scale bar, 0. 0 8 mm in each cross-section.

Fig. 7. Ventral view of Linguamyrmex sp. Computed tomography scan rendering. Mandibles of specimen BuPH- 02 viewed from below, demonstrating the channel-like structure produced when mandibles are placed together in parallel.