page_title: Zigrasimecia
section_title: Ecology
hierarchical_section_title: Zigrasimecia / Ecology
caption_attribution_description: English: Drawings of holotype of Zigrasimecia tonsora, as preserved. (C) Head, frontal view.
context_page_description: Zigrasimecia is an extinct genus of ants which existed in the Cretaceous period approximately 98 million years ago. The first specimens were collected from Burmese amber in Kachin State, 100 kilometres west of Myitkyina town in Myanmar. In 2013, palaeoentomologists Phillip Barden and David Grimaldi published a paper describing and naming Zigrasimecia tonsora. They described a dealate female with unusual features, notably the highly specialized mandibles. Other features include large ocelli, short scapes, 12 antennomeres, small eyes, and a clypeal margin that has a row of peg-like denticles. The genus Zigrasimecia was originally incertae sedis within Formicidae until a second species, Zigrasimecia ferox, was described in 2014, confirming its placement in the subfamily Sphecomyrminae.
  Due to the highly specialized mandibles, scientists believe that the ants exhibited habits no longer seen in extant ants. The highly movable head suggests that mobility was an important factor for them, and the rugose projections may have played a major role in nest excavation because the mandibles would have prevented such activity.
context_section_description: Zigrasimecia is known for its unusual morphology, and most likely had habits no longer seen in extant species. It has a highly movable head that suggests mobility was an important factor for them (this is probably for feeding behavior). The morphology of the mandibles would have prevented nest excavation, so the rugose projections on the head may have provided assistance. There is no evidence that Cretaceous ants exhibited nesting behavior, although the queen caste in Z. tonsora suggests that a dealate queen was needed for creating nests. Also, Zigrasimecia and Gerontoformica ants coexisted with each other; this is evident as a recovered piece of amber showed both genera trapped inside. This means that the two ants may have shared some of their ecological niches and possibly interacted with each other through fighting.
  It is not known what the function of the oral setae in extant species is, other than the long sensory hairs seen in some genera such as Anochetus and Odontomachus. In Zigrasimecia, the similar structures most likely did not act as trigger-hairs because they are stout and shorter. Instead, they were probably used for mechanical interactions with their food. The setae may have allowed the manipulation of liquid food, and the unification of the mandibles with other body parts such as the clypeus and labral indicates that they served as a trap for potential arthropod prey, particularly mites and small flies. Zigrasimecia was possibly a generalist predator.
  It is evident that the mandibles were highly specialized. Like other Cretaceous ants, Zigrasimecia provides further evidence that the extinct ant fauna exhibited a great diversity of feeding behavior. The unusual mouthparts of Zigrasimecia are consistent with other extinct species found in Burmese, French, New Jersey and Canadian deposits, which also show morphologies not seen in extant ants.
caption: Head, frontal view. Its unusual morphology suggests that these ants had habits no longer seen in extant species.
exif: {"Image DocumentName": "antweb1008098", "Image Software": "GIMP 2.6.11", "Image DateTime": "2013:10:14 14:13:24", "Image Artist": "Phillip Barden", "Image Copyright": "California Academy of Sciences&#44; 2002-2012", "Image ExifOffset": "192", "EXIF ExifVersion": "0220"}