''Haidoterminus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

in the Formicidae subfamily

Haidomyrmecinae Haidomyrmecinae, occasionally called Hell ants, are an extinct subfamily of ants (Formicidae) known from Cretaceous fossils found in ambers of North America, Europe, and Asia, spanning the late Albian to Campanian, around 100 to 79 million years ...

, and is one of only nine genera placed in this subfamily. The genus contains a single described species ''Haidoterminus cippus'' and is known from one

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

fossil which has been found in North America.

History and classification

''Haidoterminus'' is known from a solitary adult fossil, the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, specimen number "UASM 332546" donated for study by Mark Elaschuk. At the time of description, the specimen was residing in the Strickland Entomology Museum, part of the

University of Alberta The University of Alberta, also known as U of A or UAlberta, is a Public university, public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford,"A Gentleman of Strathcona – Alexande ...

. The holotype specimen is composed of a mostly complete

worker caste Eusociality (from Greek εὖ ''eu'' "good" and social), the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping genera ...

adult female which has been preserved as an

inclusion Inclusion or Include may refer to: Sociology * Social inclusion, aims to create an environment that supports equal opportunity for individuals and groups that form a society. ** Inclusion (disability rights), promotion of people with disabiliti ...

in a transparent chunk of clear yellow

Canadian amber Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

. The

amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In ...

specimen was recovered from deposits of the

Foremost Formation The Foremost Formation is a stratigraphic unit of Late Cretaceous (Campanian) age that underlies much of southern Alberta, Canada. It was named for outcrops in Chin Coulee near the town of ForemostGlass, D.J. (editor) 1997. Lexicon of Canadian S ...

near

Grassy Lake, Alberta Grassy Lake is a hamlet in Alberta, Canada within the Municipal District of Taber. It is located on the Crowsnest Highway ( Highway 3), midway between the cities of Lethbridge to the west and Medicine Hat to the east. It is approximately we ...

, Canada. Canadian amber has been dated to an age of approximately 79–78 million years old, placing it in the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

of the Late Cretaceous. Analysis of the amber composition indicates it originated as cupressaceous resins which were deposited in lagoons and salt water marshes along the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea ...

. ''Haidoterminus'' is one of five ant species described from the Grassy Lake site, the others being '' Sphecomyrma canadensis'', '' Eotapinoma macalpini'', '' Canapone dentata'', and '' Cananeuretus occidentalis''. The fossil was first studied by paleoentomologists Ryan C. McKellar and Michael S. Engel of the

University of Kansas The University of Kansas (KU) is a public research university with its main campus in Lawrence, Kansas, United States, and several satellite campuses, research and educational centers, medical centers, and classes across the state of Kansas. T ...

, and James R.N. Glasier of the University of Alberta. The team's 2013

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

of the new genus and species was published in the journal '' Canadian Entomology''. The genus name ''Haidoterminus'' was coined by them as a combination of ''

Haidomyrmex ''Haidomyrmex'' is an extinct genus of ants in the formicid subfamily Haidomyrmecinae, and is one of nine genera placed in the subfamily Haidomyrmecinae. The genus contains three described species ''Haidomyrmex cerberus'', ''Haidomyrmex scimit ...

'', the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

for Haidomyrmecini, and the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''terminus'' meaning "end or boundary" in allusion to the genus being the last member of the tribe Haidomyrmecini to live. The specific epithet ''cippus'', from the Latin for "tombstone or pillar", references the clypeal pads' distinct columnar appearance. ''Haidoterminus'' is one of five genera in Haidomyrmecini, the other four being ''

Ceratomyrmex ''Ceratomyrmex'' is an extinct genus of ant in the Formicidae subfamily Haidomyrmecinae. The genus contains a single described species ''Ceratomyrmex ellenbergeri'' and is known from several Late Cretaceous fossils which have been found in Asia ...

'', ''

Linguamyrmex ''Linguamyrmex'' is an extinct genus of ant in the formicid subfamily Haidomyrmecinae, and is one of only nine genera placed in the subfamily Haidomyrmecinae. The genus contains three described species, ''Linguamyrmex brevicornis'', ''Linguamy ...

'', ''

'', and ''

Haidomyrmodes ''Haidomyrmodes'' is an extinct genus of ant in the formicid subfamily Haidomyrmecinae, and is one of only nine genera placed in the subfamily Haidomyrmecinae. The genus contains a single described species, ''Haidomyrmodes mammuthus''. ''Haid ...

''.

Description

The ''Haidoterminus'' holotype worker has a similar structure to species of ''

''. The mandibles are very large and well developed with a scythe-shaped appearance in side view and notably narrow bases. The holotype is overall approximately with small oval shaped

compound eyes A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distin ...

made up of a larger

ommatidia The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium). An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The ...

in low numbers. The clypeus has a concave structure sporting several larger

setae In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. ...

including two long trigger setae. The antennae are distinct in having a total of twelve segments, in contrast to the eleven segments seen in ''Haidomyrmex'' and ''Haidomyrmodes''. ''Haidoterminus'' has an elongated third antennomere and a bulb shaped terminal flagellomere, while the antennae have an overall coating of short inclined setae.

References

External links

* {{Taxonbar, from=Q16753242 Monotypic fossil ant genera Cretaceous insects Fossil taxa described in 2013 † Haidomyrmecinae Prehistoric insects of North America Canadian amber Taxa named by Michael S. Engel