''Electrostephanus'' 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 ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of crown wasp in the

hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...

n family

Stephanidae The Stephanidae, sometimes called crown wasps, are a family (biology), family of parasitoid wasps. They are the only living members of the superfamily Stephanoidea. Stephanidae has at least 345 living species in 11 genera. The family is considere ...

, and is the only genus placed in the subfamily Electrostephaninae. The genus contains four described species, ''E. brevicornis'', ''E. neovenatus'', ''E. janzeni'', and ''E. petiolatus'', placed in two subgenera ''E. (Electrostephanus)'' and ''E. (Electrostephanodes)''. ''Electrostephanus'' is known from several

middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

fossils which have been found in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

History and classification

''Electrostephanus'' is known from a group of fossils preserved as an inclusions in transparent chunks of

Baltic amber Baltic amber or succinite is amber from the Baltic region, home of its largest known deposits. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that this forested region provided the re ...

and is named after the Greek term for amber, ἤλεκτρον (elektron). Baltic amber is approximately forty-six million years old, having been deposited during

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

stage of the

Middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

. There is debate as to what plant family the amber was produced by, with evidence supporting relatives of either ''

Agathis ''Agathis'', commonly known as kauri or dammara, is a genus of evergreen coniferous trees, native to Australasia and Southeast Asia. It is one of three extant genera in the family Araucariaceae, alongside ''Wollemia'' and ''Araucaria'' (being ...

'' or ''

Pseudolarix ''Pseudolarix'' is a genus of coniferous trees in the pine family Pinaceae containing three species, the extant '' Pseudolarix amabilis'' and the extinct species '' Pseudolarix japonica'' and '' Pseudolarix wehrii''. ''Pseudolarix'' species are ...

'' trees. The genus was originally described by paleoentomologist

Charles Thomas Brues Charles Thomas Brues (June 20, 1879, Wheeling, West Virginia – July 22, 1955, Crescent City, Florida, Crescent City, Florida) was an American entomologist. Biography Brues studied at the University of Texas at Austin and at Columbia Univers ...

in 1933 with Brues designating ''E. petiolatus'' as the type species, and including two other species, ''E. tridentatus'' and ''E. brevicornis''. A fourth species, ''"E." sulcatus'' and fifth, ''E. neovenatus'', were described by Alexandre Aguiar and Jens-Wilhelm Janzen 1999, and a sixth species. ''E. janzeni'', was described in 2005. The original type specimens for ''E. petiolatus'', ''"E." tridentatus'' and ''"E." brevicornis'' were part of the Albertus Universität, Königsberg collection of ambers, and all were possibly lost to fire during the bombing of

Kaliningrad Kaliningrad,. known as Königsberg; ; . until 1946, is the largest city and administrative centre of Kaliningrad Oblast, an Enclave and exclave, exclave of Russia between Lithuania and Poland ( west of the bulk of Russia), located on the Prego ...

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Based on the structure of the petiole and abdomen in ''"E.". sulcatus'' and the suggestion that ''E. petiolatus'' had the same morphology, ''Electrostephanus'' was designated a

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

of '' Denaeostephanus'' in 2004. However, this move was reversed with the description of an additional male ''E. petiolatus'' specimen in 2008 by Michael S. Engel and Jaime Ortega-Blanco, who designated the new specimen the

neotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes ...

for ''E. petiolatus''. Engel and Ortega-Blanco transferred the species back to ''Electrostephanus'' along with ''E. brevicornis'', ''E. neovenatus'', and ''E. janzeni'', but retaining ''D. tridentatus'' in ''Denaeostephanus''. Based on the abdomen morphology Engel and Ortega-Blanco further split the genus into two distinct subgenera, ''E. (Electrostephanus)'' containing the type species ''E. petiolatus'', and ''E. (Electrostephanodes)'' containing the remaining three species. They noted that ''Electrostephanodes'' may merit elevation to full genus status, but the lack of additional known fossil specimens to consult meant they opted for a conservative subgenus placement.

Description

The ''Electrostephanus petiolus'' male adult has an elongated body which is long with an overall coloration ranging from black to dark brown and having scattered

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e. The head capsule is generally spherical with rounded

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 ...

on the lateral surface. The typical "crown" is a group of five tubercles places in front of four small ridges running crossways over the head capsule. The antennae are composed of 22

flagellomeres An antenna (plural: antennae) is one of a pair of appendages used for sensing in arthropods. Antennae are sometimes referred to as ''feelers''. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in ...

and scape, attaching to the head near the mid-line of the compound eyes. The wings are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

in coloration, with a dark brown pterostigma that is parallel sided and the estimated fore-wing length is . The metasoma is narrow and forms a

petiole Petiole may refer to: *Petiole (botany), the stalk of a leaf, attaching the blade to the stem *Petiole (insect anatomy) In entomology, petiole is the technical term for the narrow waist of some hymenopteran insects, especially ants, bees, and ...

References

{{Taxonbar, from=Q18353150 Lutetian insects Fossil taxa described in 1933 Fossil taxa described in 1999 Fossil taxa described in 2005 Eocene insects of Europe †Electrostephanus Baltic amber Prehistoric Hymenoptera genera Taxa named by Charles Thomas Brues Lutetian genera