Electromyrmococcus
Encyclopedia
Electromyrmococcus is an extinct genus
of mealybug
in the Pseudococcidae subfamily Rhizoecinae. The genus currently contains three species, all from the early Miocene
, Burdigalian
stage, Dominican amber
deposits on the island of Hispaniola
.
. The genus name is a combination of electro, from the Greek
() meaning "amber", myrmo from the Greek () meaning "ant" and Coccus
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.
Electromyrmococcus species have an enlarged cephalothorax
and an abdomen that gradually tapers down to a pointed end. Along the last segments of the abdomen are a number of seta
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 mandibles of Acropyga
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
and gyne
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.
, a single elongated piriform
female 0.7 millimetre (0.0275590551181102 in) long, clutched in the mandibles of an Acropyga species ant. 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
in the Cibao Valley
. The holotype is deposited in the Senckenberg Museum of Frankfurt
, Germany
. The species epithet
, which is Latin
for "carried off", was chosen by Williams in reference to the mealybug being preserved in the ant's mandibles.
as "number DR-14–403". The female is 0.76 millimetre (0.0299212598425197 in) 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
. 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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of mealybug
Mealybug
Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm climates. They are considered pests as they feed on plant juices of greenhouse plants, house plants and subtropical trees and also acts as a vector for several plant diseases.-Distribution:Mealybugs...
in the Pseudococcidae subfamily Rhizoecinae. The genus currently contains three species, all from the early Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
, Burdigalian
Burdigalian
The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma...
stage, Dominican amber
Dominican amber
Dominican amber is amber from the Dominican Republic. Resin from the extinct species Hymenaea protera is the source of Dominican amber and probably of most amber found in the tropics....
deposits on the island of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
.
History and classification
The genus was first described by Douglas Williams as an appendix to a 2001 paper published in the journal American Museum NovitatesAmerican Museum Novitates
American Museum Novitates is an academic journal published by the American Museum of Natural History. The journal was founded in 1921....
. The genus name is a combination of electro, from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
() meaning "amber", myrmo from the Greek () meaning "ant" and Coccus
Coccus (insect)
Coccus is a genus of scale insects in the family Coccidae. It includes species such as Coccus viridis, a major pest of coffee.-Species:* Coccus celatus* Coccus hesperidum* Coccus pseudomagnoliarum* Coccus viridis...
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 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
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
and an abdomen that gradually tapers down to a pointed end. Along the last segments of the abdomen are a number of seta
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
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 mandibles of Acropyga
Acropyga
Acropyga is a genus of small formicine ants.Some species can be indirect pests. A. acutiventris, which is found from India to Australia, tends subterranean, root-feeding mealybugs of the species Xenococcus annandalei. Living, gravid females are carried in the jaws of A...
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
Queen ant
A queen ant is an adult, reproducing female ant in an ant colony; generally she will be the mother of all the other ants in that colony. Some female ants do not need to mate to produce offspring, reproducing through asexual parthenogenesis or cloning and all of those offspring will be female.Ant...
and gyne
Gyne
Gyne is the primary reproductive female caste of social insects . Gynes are those destined to become queens, whereas female workers are typically sterile and cannot become queens...
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 holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, a single elongated piriform
Piriform
Piriform is a privately owned software house based in the West End of London, UK. It develops software for the Microsoft Windows and Mac OS X operating systems. Piriform's projects include CCleaner, Recuva, Defraggler, and Speccy, with at least two more products under development for a future...
female 0.7 millimetre (0.0275590551181102 in) long, clutched in the mandibles of an Acropyga species ant. 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
Santiago de los Caballeros is a city in the Dominican Republic. Founded in 1495 during the first wave of European colonization of the New World, today Santiago is the second largest metropolis in the Dominican Republic, located in the north-central region of the Republic known as Cibao valley...
in the Cibao Valley
Cibao
Cibao, usually referred as "El Cibao", is a region of the Dominican Republic located at the northern part of the country.The Taíno word Cibao, meaning "place where rocks abound", was originally applied to the central mountain range, and used during the Spanish conquest to refer to the rich and...
. The holotype is deposited in the Senckenberg Museum of Frankfurt
Frankfurt
Frankfurt am Main , commonly known simply as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2010 population of 688,249. The urban area had an estimated population of 2,300,000 in 2010...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. The species epithet
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, which is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
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 HistoryAmerican Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
as "number DR-14–403". The female is 0.76 millimetre (0.0299212598425197 in) 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
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
. 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.