Martialis heureka

Martialis heureka
	Martialis heureka , holotype . Image Michael Branstetter, Antweb
Systematics
Order :	Hymenoptera (Hymenoptera)
Family :	Ants (Formicidae)
Subfamily :	Martialinae
Genre :	Martialis
Type :	Martialis heureka
Scientific name of the subfamily
	Martialinae
	Rabeling & Verhaagh , 2008
Scientific name of the genus
	Martialis
	Rabeling & Verhaagh, 2008
Scientific name of the species
	Martialis heureka
	Rabeling & Verhaagh, 2008

Martialis heureka (of lat. Martialis "Martian" and Greek. Εύρηκα "I have found it") is an ant art , created in 2008 by Christian Rabeling and Manfred Verhaagh from the Natural History Museum in Karlsruhe has been described. The scientific name indicates the species' unusual appearance and complicated history of discovery. To date only three workers of the species have been found.

features

Martialis heureka was described after a single worker. Sex animals and larvae are unknown.

The animal is three millimeters long, pale in color, and eyeless. The cuticle is mostly smooth and sparsely sculpted, it is hairy sparsely protruding in sections. The head has two noticeably long and very narrow, tweezer-like mandibles , which are turned far outside of the head capsule. These are serrated in the middle and sickle-shaped (falciform) towards the tip. The clypeus is small and largely regressed, it has a brush-like hair on its front edge. Unlike most other ants, the head has neither frontal lobes nor antenna pits or keels, the antenna bases at the front edge of the clypeus are freely visible from above. The antennae are twelve-segment with a relatively short basal or stalk segment (scapus). The head sits with a narrow neck region on the trunk section. On the narrow and slender trunk section, the seam between the pronotum and mesonotum is clear, the trunk is flexible here. The Propodeum has neither praises nor thorns or any other special features. The opening of the metapleural glands is slit-shaped and freely visible. On the legs, the front legs are significantly elongated and enlarged. The claws of the tarsi are simple and imperforate. The petiolus is rounded in side view, it consists of only one, fused, sclerite. The free abdomen or gaster begins with a postpetiolus, which is somewhat constricted in a ring compared to the rest of the gaster, but is not set off. The free gaster is teardrop-shaped in side view and somewhat compressed at the sides, its first segment (the fourth abdominal segment) is about twice as long as the postpetiolus. The guest has a very weak but functional poison sting inside.

Site, find history

The only known locality of the species is the area around Manaus , Amazonia , Brazil . In 1998, two of Manfred Verhaagh's workers were found there in a soil sample, and the material was deposited in a museum, where it could not initially be found. After an intensive search, Christian Rabeling managed to find another specimen five years later on the surface of the ground during the twilight in another, nearby forest; this became the holotype of the first description (see photo above). Both sites are in the primary tropical rainforest .

The first two animals reappeared later. Unfortunately, they were largely destroyed by a series of mishaps, so that only a few isolated remains remain. There have been no further finds to this day.

Biology and way of life

Since only three animals have been discovered to date, all information on the way of life of the species is more or less speculative. Due to the physique and the circumstances of the find, however, an underground way of life, either in the ground itself or in the litter , is considered safe. However, the anatomy does not give any indications of an active ability to dig. The particular structure of the mouthparts makes a predatory diet highly likely.

Phylogeny

Martialis has a number of characteristics in common with the species of the subfamily Leptanillinae , which also live underground , including: missing eyes, trunk section (Alitrunk) movable through a continuous suture, antenna bases free, frontal lobes missing. The special structure of the head and the mouthparts, especially the clypeus and the mandibles, cannot be found in any other group of ants. It is therefore not only placed in its own genus, but even monotypically (as the only species) in its own subfamily.

Relationship analyzes based on the comparison of homologous DNA sequences (phylogenomics) revealed an isolated and basal position. Depending on the analysis, the species was either the most original ant that was still alive, together with all the others as a sister group , or this position belonged to the Leptanillinae; in this case it branched off in the next position, with all remaining species except the Leptanillinae as sister group. It is striking that not only these two, but almost all of the most pristine groups of ants still alive appear to have been adapted to an underground (hypogean) way of life. It has therefore already been assumed that this way of life must have been the original for the "modern" ants (without the extinct Armadiinae and Sphecomyrminae). According to this, all groups living above ground would have emerged from hypogean.

swell

C. Rabeling, JM Brown, M. Verhaagh: Newly discovered sister lineage sheds light on early ant evolution . In: PNAS . 2008. doi : 10.1073 / pnas.0806187105 .
Carlos Roberto Ferreira Brandão, Jorge Luis Machado Diniz, Rodrigo dos Santos Machado Feitosa (2010): The venom apparatus and other morphological characters of the ant Martialis heureka (Hymenoptera, Formicidae, Martialinae). Papéis Avulsos de Zoologia (São Paulo) Volume 50 (26): 413-423.
Patrick Kück, Francisco Hita Garcia, Bernhard Misof, Karen Meusemann (2011): Improved Phylogenetic Analyzes Corroborate a Plausible Position of Martialis heureka in the Ant Tree of Life. PLoS ONE 6 (6): e21031. doi : 10.1371 / journal.pone.0021031
Andrea Lucky, Michelle D. Trautwein, Benoit S. Guenard, Michael D. Weiser, Robert R. Dunn (2013): Tracing the Rise of Ants - Out of the Ground. PLoS ONE 8 (12): e84012. doi : 10.1371 / journal.pone.0084012