''Mastotermes electromexicus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

termite Termites are a group of detritivore, detritophagous Eusociality, eusocial cockroaches which consume a variety of Detritus, decaying plant material, generally in the form of wood, Plant litter, leaf litter, and Humus, soil humus. They are dist ...

in the family Mastotermitidae known from a group of

Late Oligocene The Chattian is, in the geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the pro ...

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

fossils found in

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. ''M. electromexicus'' is the only species in the genus '' Mastotermes'' to have been described from fossils found in

Mexican amber Mexican amber, also known as Chiapas Amber is amber found in Mexico, created during the Early Miocene and middle Miocene epochs of the Cenozoic Era in southwestern North America. As with other ambers, a wide variety of taxa have been found as in ...

and was the first member of the genus described from the New World. The only living species of ''Mastotermes'' is ''

Mastotermes darwiniensis ''Mastotermes darwiniensis'', common names giant northern termite and Darwin termite, is a termite species found only in northern Australia. It is the most primitive extant termite species. Contrary to common belief, this species does not form m ...

'' which is found in tropical regions of

Northern Australia The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26th parallel south, 26° and all of the Northern Territory. Those local government areas of Western Australia and Q ...

History and classification

''Mastotermes electromexicus'' is known from a series of fourteen fossil insects which are inclusions in transparent chunks of Mexican amber. The amber specimens, a

soldier A soldier is a person who is a member of an army. A soldier can be a Conscription, conscripted or volunteer Enlisted rank, enlisted person, a non-commissioned officer, a warrant officer, or an Officer (armed forces), officer. Etymology The wo ...

, an imago and twelve nymphs are currently housed in the fossil collection of the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

Berkeley, California Berkeley ( ) is a city on the eastern shore of San Francisco Bay in northern Alameda County, California, United States. It is named after the 18th-century Anglo-Irish bishop and philosopher George Berkeley. It borders the cities of Oakland, Cali ...

. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

fossil is composed of a partial soldier caste individual. Mexican amber is recovered from fossil bearing rocks in the

Simojovel Simojovel is a Municipalities of Chiapas, municipality in the List of states in Mexico, Mexican state of Chiapas in southern Mexico. As of 2010, the municipality had a total population of 40,297, up from 31,615 as of 2005. It covers an area of ...

region of

Chiapas Chiapas, officially the Free and Sovereign State of Chiapas, is one of the states that make up the Political divisions of Mexico, 32 federal entities of Mexico. It comprises Municipalities of Chiapas, 124 municipalities and its capital and large ...

, Mexico. The amber dates from between 22.5 million years old, for the youngest sediments of the Balumtun Sandstone, and 26 million years old La Quinta Formation. This age range straddles the boundary between the

and

and is complicated by both formations being secondary deposits for the amber, the age range is only the youngest that it might be. The holotype was first studied by entomologists

Kumar Krishna Kumar Krishna (21 June 1928-19 September 2014) was an American entomologist of Indian origin. He was an expert on the termites and published the definitive systematic treatment of the termites of the world in a seven volume ''Treatise on the Isopte ...

of the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

and Alfred Emerson of the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

. Krishna and Emerson's 1983

type description A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

of the species was published in the

natural sciences Natural science or empirical science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer ...

journal ''

American Museum Novitates ''American Museum Novitates'' is a peer-reviewed academic journal published by the American Museum of Natural History. It was established in 1921. According to the ''Journal Citation Reports'', the journal has a 2013 impact factor The impact ...

''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''electromexicus'' was coined from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

word "ēlektron" meaning ''amber'' combined with Mexico as a reference to the nature of the preservation and the country of the type locality.

Description

The ''Mastotermes electromexicus'' soldier is known from only a portion of the head and mandible. The head is estimated to have been wide with

long hairs Long may refer to: Measurement * Long, characteristic of something of great duration * Long, characteristic of something of great length * Longitude (abbreviation: long.), a geographic coordinate * Longa (music), note value in early music mensu ...

on each side of the head below the antennae. The mandibles are gently curved inwards, in contrast to those of ''M. darwiniensis'' which are a more curved and having a hooked appearance. The imago is known from a partial head, thorax, and hind wings. The wide head of the imago is wider than seen in ''M. darwiniensis'' with smaller eyes and

ocelli A simple eye or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

which do not touch the compound eyes. The nymphs are known from a series of partial fossils in thirteen pieces of amber and representing several different

instars An instar (, from the Latin ''wikt:instar#Latin, īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each ecdysis, moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the ...

. The heads vary between , showing a larger range of size then those of ''M. darwiniensis''. The antennae have approximately twenty four segments, flagellomeres, and the legs host a number of bristles and several short spines.

References

{{Taxonbar, from=Q6785607 Termites Oligocene insects of North America Miocene insects of North America Mexican amber Fossil taxa described in 1983