''Astreptolabis'' 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 ...

earwig Earwigs make up the insect order (biology), order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cercus, cerci, a pair of forceps-like pincer (biology), pincers on ...

in the

Dermaptera Earwigs make up the insect order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forceps-like pincers on their abdomen, and membranous wings folde ...

family

Pygidicranidae Pygidicranidae is a family of earwigs in the suborder Neodermaptera. The family currently contains twelve subfamilies and twenty six genera. Eight of the subfamilies are monotypic, each containing a single genus. Of the subfamilies, both Astre ...

known from a group of

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

fossils found in

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

. The genus contains two described species, ''Astreptolabis ethirosomatia'' and ''Astreptolabis laevis'' and is the sole member of the subfamily Astreptolabidinae.

History and classification

''Astreptolabis ethirosomatia'' is known only from a single fossil, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

, specimen number AMNH Bu-FB20, which is housed in the Amber Fossil Collection of the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

New York City New York, often called New York City (NYC), is the most populous city in the United States, located at the southern tip of New York State on one of the world's largest natural harbors. The city comprises five boroughs, each coextensive w ...

. The specimen is composed of a fully complete adult female earwig which has been preserved as an

inclusion Inclusion or Include may refer to: Sociology * Social inclusion, action taken to support people of different backgrounds sharing life together. ** Inclusion (disability rights), promotion of people with disabilities sharing various aspects of lif ...

in a transparent chunk of

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. Th ...

. The age of the amber deposits in

Kachin State Kachin State (; Jingpho language, Kachin: ) is the northernmost administrative divisions of Myanmar, state of Myanmar. It is bordered by China to the north and east (Tibet Autonomous Region, Tibet and Yunnan, respectively), Shan State to the sou ...

of northernmost Burma are understood to be about 100 million years old, placing them in the earliest part of the

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

stage of the Cretaceous. The ''Astreptolabis'' ''ethirosomatia'' holotype was recovered from outcrops near the city of

Myitkyina Myitkyina (, ; Jingpho language, Jinghpaw: ''Myitkyina'', ; , ''Sèna'') is the capital city of Kachin State in Myanmar (Burma), located from Yangon, and from Mandalay. In Burmese language, Burmese it means "near the big river", and Myitkyina i ...

and was first studied by paleoentomologist Michael S. Engel of the Division of Entomology at the

University of Kansas The University of Kansas (KU) is a public research university with its main campus in Lawrence, Kansas, United States. Two branch campuses are in the Kansas City metropolitan area on the Kansas side: the university's medical school and hospital ...

Lawrence, Kansas Lawrence is a city in and the county seat of Douglas County, Kansas, United States, and the sixth-largest city in the state. It is in the northeastern sector of the state, astride Interstate 70 in Kansas, Interstate 70, between the Kansas River ...

. Engel's 2011

type description A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

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

ZooKeys ''ZooKeys'' is a peer-reviewed open access scientific journal covering zoological taxonomy, phylogeny, and biogeography. It was established in 2008 and the founding editor-in-chief was Terry Erwin (Smithsonian Institution The Smithsonian ...

''. The genus name ''Astreptolabis'' was coined by Engel as a combination of

Greek Greek may refer to: 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 of all kno ...

words ''astreptos'', which means "not curved" and ''labis'', which means "forceps". This is in reference to the distinct structuring of the type specimens cerci or "pincers". The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''ethirosomatia'' is from the Greek words ''etheira'', meaning "hairy" and ''somation'', the diminutive of the Greek word for "body". The subfamily name Astreptolabidinae is derived from the genus name with the suffix -''inae'' added. In 2020 a second species. ''A. laevis'' was described. Several other earwing species have been found in

. One other species '' Tytthodiplatys mecynocercus'' was described by Engel in the same 2011 paper, while '' Burmapygia resinata'' was described by Engel and David Grimaldi in 2004, with a fourth species '' Myrrholabia electrina'' first described by Theodore Cockerell in 1920. An additional fifth and sixth species '' Zigrasolabis speciosa'' and '' Toxolabis zigrasi'' were described by Engel and Grimaldi in 2014 paper.

Description

The holotype specimen of ''Astreptolabis ethirosomatia'' is a complete adult female with an overall coloration that appears to be mat brown to dark brown. The female is approximately in length when the cerci are included. The body is overall densely covered in

setae 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 ...

that are not thickened enough to be chaetulose. The antennae have a stout scape and are at least fourteen flagellomeres long. As is typical with earwigs, the

forewings Insect wings are adult outgrowths of the insect exoskeleton that enable insect flight, insects to fly. They are found on the second and third Thorax (insect anatomy), thoracic segments (the mesothorax and metathorax), and the two pairs are often ...

have been modified into tegma. The tegma cover the four first segments of the abdomen and the abdomen comprises eight visible segments, also typical for female earwigs. The hind wings are present, but due to positioning of the tegma, are mostly obscured. The slender cerci are tubular and straight, tapering along the length to sharp points at the ends. ''A. laevis'' is known from a holotype male, it is distinguished from ''A. ethirosomatia'' by more sparse setation on the head,

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

, and

tegmina A tegmen (: tegmina) designates the modified leathery front wing on an insect particularly in the orders Dermaptera (earwigs), Orthoptera (grasshoppers, crickets and similar families), Mantodea (praying mantis), Phasmatodea (stick and leaf insec ...

, larger compound eyes and absence of ocular setae.

References

{{Taxonbar, from=Q4811399 Dermaptera genera Early Cretaceous insects Fossil taxa described in 2011 Cretaceous insects of Asia Burmese amber Fossils of Myanmar Taxa named by Michael S. Engel Earwigs