''Allorapisma'' 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 ...

lacewing The insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order consists of some 6,000 species. Neuroptera can be grouped together with the Megaloptera and Raphidioptera in t ...

in the moth lacewings family

Ithonidae Ithonidae, commonly called moth lacewings and giant lacewings, is a small family of winged insects of the insect order Neuroptera. The family contains a total of ten living genera, and over a dozen extinct genera described from fossils. The mod ...

. The genus is solely known from two

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

fossils found in North America. At the time of description the genus was composed of a single species, ''Allorapisma chuorum''.

History and classification

''Allorapisma chuorum'' is known only from two fossils, the part side of 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 ...

left fore-wing, specimen number SR 08-14-01, and the part side of a

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

right fore-wing, specimen number SRUI 08-04-01. Both the fossil are currently housed in the collections of the

Stonerose Interpretive Center The Stonerose Interpretive center & Eocene Fossil Site is a 501c(3) non-profit public museum and fossil dig located in Republic, Washington. The center was established in 1989 and houses fossils that have been featured in ''National Geographic M ...

Republic, Washington Republic is a city in Ferry County, Washington, United States. The population was 1,073 at the 2010 census, a 12.5% increase over the 2000 census. It is the county seat of Ferry County. It was the largest mining camp in the Republic Mining Distr ...

, US. The specimens are preserved as

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason fo ...

s in silty yellow to grayish

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

, which were recovered from outcrops of the Tom Thumb Tuff member of the

Klondike Mountain Formation The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Wash ...

. The formation is approximately

Early Eocene In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

in age, being radiometrically dated as . ''Allorapisma'' was first studied by the paleoentomologists Vladimir N. Makarkin of the

Far Eastern Branch of the Russian Academy of Sciences The Far Eastern Branch of the Russian Academy of Sciences (Russian:Дальневосточное отделение Российской академии наук)( abbr. FEB RAS) is a regional branch of the Russian Academy of Sciences The Rus ...

and S. Bruce Archibald from

Simon Fraser University Simon Fraser University (SFU) is a public research university in British Columbia, Canada, with three campuses, all in Greater Vancouver: Burnaby (main campus), Surrey, and Vancouver. The main Burnaby campus on Burnaby Mountain, located from ...

Burnaby, British Columbia Burnaby is a city in the Lower Mainland region of British Columbia, Canada. Located in the centre of the Burrard Peninsula, it neighbours the City of Vancouver to the west, the District of North Vancouver across the confluence of the Burrard Inl ...

. Their 2009

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

of the new genus and species was published in the online journal ''

Zootaxa ''Zootaxa'' is a peer-reviewed scientific mega journal for animal taxonomists. It is published by Magnolia Press (Auckland, New Zealand). The journal was established by Zhi-Qiang Zhang in 2001 and new issues are published multiple times a week. ...

''. The genus name ''Allorapisma'' was coined by the researchers as a combination of the moth lacewing type genus '' Rapisma'' and 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 ...

word ''Allo'' meaning "other", which is in reference to the similarity of the new genus to ''Rapisma''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''chuorum'' is honor of the Chu family from

Kirkland, Washington Kirkland is a city in King County, Washington, United States. A suburb east of Seattle, its population was 92,175 in the 2020 U.S. census which made it the sixth largest city in the county and the twelfth largest in the state. The city's downto ...

who found the holotype and donated it to the Stonerose Interpretive Center. Overall the vein structure of ''Allorapisma'' is most similar to the genus '' Principiala'', known from

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

fossils found in both Brazil and England. Following the

Comstock–Needham system The Comstock–Needham system is a naming system for insect wing veins, devised by John Comstock and George Needham in 1898. It was an important step in showing the homology of all insect wings. This system was based on Needham's ''pretracheati ...

, the wings of both genera show the apical end of the Rs vein fused to the MA vein. Both have similar positioning and shaping of the MP vein and the CuA vein running parallel to the MP vein. As such, Makarkin and Archibald suggested the two be grouped in an informal suprageneric group called the ''Principiala'' group. This group is one of three possibly

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

groups in

, the others two being the ''Ithone'' group and the ''Rapisma'' group. Before the merging of the families Ithonidae and

Polystoechotidae Ithonidae, commonly called moth lacewings and giant lacewings, is a small family of winged insects of the insect order Neuroptera. The family contains a total of ten living genera, and over a dozen extinct genera described from fossils. The mo ...

in 2010, ''Allorapisma'' was the first Ithonidae fossil to be described from the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

Description

The holotype and paratype are both composed of partially complete fore-wings, each of which is missing a sections of the lower wing edge. The preserved section of the holotype fore-wing is approximately long and wide. The paratype is slightly longer at and wide. The wings have a costal space that is wide, widening towards the wing base and narrowing towards the wing tip. The space between the R1 and Rs veins is notably larger than the subcostal space, while the costal space has several crossveins near the edge of the costal margin. The MA and MP veins are distinct in origins from each other, with the MA starting at the R vein, a character that is rare in Neuroptera.

References

{{Taxonbar, from=Q4733141 Ithonidae Fossil taxa described in 2009 Ypresian insects Eocene insects of North America Klondike Mountain Formation