''Electromyrmococcus'' is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
mealybug
Mealybugs are insects in the family (biology), family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Many species are considered pest (animal), pests as they feed on plant juices of greenhouse plants, house plants and sub ...
in the
Pseudococcidae
Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Many species are considered pests as they feed on plant juices of greenhouse plants, house plants and subtropical trees and also act as a ...
subfamily
Rhizoecinae.
The genus currently contains three species, all
from the early
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
,
Burdigalian
The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...
stage,
Dominican amber
Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree ''Hymenaea protera''.
Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil incl ...
deposits on the island of
Hispaniola
Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...
.
History and classification
The genus was first described by
Douglas Williams as an appendix to a 2001 paper published in the 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 f ...
''.
The genus name is a combination of ''electro'', from the
Greek
Greek may refer to:
Greece
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 ...
(') meaning "
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 Ma ...
", ''myrmo'' from the Greek (') meaning "ant" and ''
Coccus
A coccus (plural cocci) is any bacterium or archaeon that has a spherical, ovoid, or generally round shape. Bacteria are categorized based on their shapes into three classes: cocci (spherical-shaped), bacillus (rod-shaped) and spiral ( of whi ...
'' from the ant-tended genus of mealybugs, in reference to the association of ant and mealybugs in amber.
Along with the genus description, the paper contained the description of the
type species ''E. abductus'' and the two additional species ''E. inclusus'' and ''E. reginae''.
Description
''Electromyrmococcus'' possesses a combination of traits which are not found in any one
modern
Modern may refer to:
History
* Modern history
** Early Modern period
** Late Modern period
*** 18th century
*** 19th century
*** 20th century
** Contemporary history
* Moderns, a faction of Freemasonry that existed in the 18th century
Phil ...
genus belonging to the Rhizoecinae, a subfamily of the mealybugs. Living Rhizoecinae are separated into two groups of closely related genera, the ''
Rhizoceus'' group and the ''
Eumyrmococcus'' group.
Antennae of the ''
Rhizoceus'' group have six segments, at least as wide as they are long. The antennae of the ''Eumyrmococcus'' group have two to five long slender segments. ''Electromyrmococcus'' has long slender antennae with six segments.
''Electromyrmococcus'' species have an enlarged
cephalothorax
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
and an abdomen that gradually tapers down to a pointed end. Along the last segments of the abdomen are a number of
seta
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. Th ...
e which may be grouped on small poorly developed anal lobes or spaced out on the ventral margin of the abdominal segment.
All known specimens of ''Electromyrmococcus'' are preserved in amber, and all are either being clutched in the
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
s of ''
Acropyga glaesaria
''Acropyga glaesaria'' is an extinct species of ant in the subfamily Formicinae known from a group of possibly Miocene fossils found on Hispaniola. ''A. glaesaria'' is the first species of the ant genus '' Acropyga'' to have been described from f ...
'' species ants,
or in other close association with them.
Mealybugs in the Rhizoecinae subfamily are often
obligatorily symbiotic with ''Acropyga'' species; when forming new nests the
queens
Queens is a borough of New York City, coextensive with Queens County, in the U.S. state of New York. Located on Long Island, it is the largest New York City borough by area. It is bordered by the borough of Brooklyn at the western tip of Long ...
and
gyne
The gyne (, from Greek γυνή, "woman") is the primary reproductive female caste of social insects (especially ants, wasps, and bees of order Hymenoptera, as well as termites). Gynes are those destined to become queens, whereas female workers ...
s will bring a seed "herd" of mealybugs from the old colony. This carrying behavior is the probable reason for the preservation of the ''Electromyrmococcus'' specimens and represents the oldest record of this symbiosis.
''E. abductus''
''E. abductus'' was described from 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 several ...
, a single elongated
piriform female long, clutched in the mandibles of an ''Acropyga glaesaria'' adult.
Very weakly formed anal lobes are found on segment eight of the abdomen and each lobe has four setae. Setae are also present on the abdominal segments leading to segment eight. The amber was recovered from the La Toca mine group northeast of
Santiago de los Caballeros
Santiago de los Caballeros (; '' en, James, son of Zebedee, Saint James of the Knights''), often shortened to Santiago, is the second-largest city in the Dominican Republic and the fourth-largest city in the Caribbean by population. It is the cap ...
in the
Cibao Valley
The Cibao, usually referred as "El Cibao", is a region of the Dominican Republic located at the northern part of the country. As of 2009 the Cibao has a population of 5,622,378 making it the most populous region in the country.
The region constitu ...
.
The holotype is deposited in the
Senckenberg Museum
The Naturmuseum Senckenberg is a museum of natural history, located in Frankfurt am Main. It is the second-largest of its type in Germany. The museum contains a large and diverse collection of birds with 90,000 bird skins, 5,050 egg sets, 17,0 ...
of
Frankfurt
Frankfurt, officially Frankfurt am Main (; Hessian: , "Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on its na ...
,
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
. The
species epithet ', which is
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 ...
for "carried off", was chosen by Williams in reference to the mealybug being preserved in the ant's mandibles.
''E. inclusus''
''E. inclusus'' is the second species which was named in the 2001 paper. The holotype female, and only specimen, is deposited in the
American Museum of Natural History
The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...
as "
number
A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers c ...
DR-14–403".
The female is long with a typical tapering abdomen. The abdomen has well-defined segments with segment eight possessing slightly developed anal lobes sporting four setae each, and segment two with a pair of submedial projections. The female has a notable constriction present between the abdomen and the thorax. However the constriction was probably not a feature possessed by the species in life, but rather though to be a result of being compressed by the ant closely associated with it when they became trapped in
resin
In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...
. Williams collaborated with
Donat Agosti in the description of ''E. inclusus''. They chose the specific epithet ' which is a Latin participle meaning "enclosed" or "imprisoned" in allusion to the female's preservation in amber.
''E. reginae''
The third known species is ''E. reginae'', which, like the other known species, is known from a single female specimen preserved in amber. ''E. reginae'' is the largest of the three species at in length.
Noted to be closely related to ''E. inclusus'', the anal lobes of ''E. reginae'' are not as well developed but do possess four setae each. The well-developed legs of ''E. reginae'' also have some setae present. Like ''E. abductus'' the ''E. reginae'' female was preserved in the mandibles of an ''Acropyga glaesaria'' ant, this one a queen. In reference to this the specific epithet ''reginae'' comes from the Latin ' meaning "belonging to a queen".
References
{{Taxonbar, from=Q16752647
†
†
Extinct Hemiptera
Prehistoric insect genera
Burdigalian life
Neogene Dominican Republic
Miocene insects of North America
Prehistoric insects of the Caribbean
†
†
Fossils of the Dominican Republic
Dominican amber
Fossil taxa described in 2001