''Electrostephanus'' 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 crown wasp in the

hymenoptera Hymenoptera is a large order (biology), order of insects, comprising the sawfly, 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 Par ...

n family

Stephanidae The Stephanidae, sometimes called crown wasps, are a 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 considered cosmopolitan in ...

, 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 ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

fossils which have been found in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

History and classification

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

Baltic amber The Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that these forests created more than 1 ...

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 or 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 is sometimes referred to as the Midd ...

stage of the

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

. 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 22 species of evergreen tree. The genus is part of the ancient conifer family Araucariaceae, a group once widespread during the Jurassic and Cretaceous periods, but now largely re ...

'' 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 c ...

'' 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) was an American entomologist. Biography Brues studied at the University of Texas at Austin and at Columbia University. He was appointed f ...

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 ( ; rus, Калининград, p=kəlʲɪnʲɪnˈɡrat, links=y), until 1946 known as Königsberg (; rus, Кёнигсберг, Kyonigsberg, ˈkʲɵnʲɪɡzbɛrk; rus, Короле́вец, Korolevets), is the largest city and ...

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. 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 The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

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 attached. In other words, a type is an example that serves to anchor or centralizes the ...

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 (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. 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 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 el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

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.

References

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