''Astreptolabis'' 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 ...

earwig 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 forcep-like pincers on their abdomen, and membranous wings folded ...

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 forcep-like pincers on their abdomen, and membranous wings folded ...

family

Pygidicranidae Pygidicranidae is a family of earwigs, formerly placed in the suborder Forficulina, now in the suborder Neodermaptera. The family currently contains twelve subfamilies and twenty six genera. Eight of the subfamilies are monotypic, each containi ...

known from a group of

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

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

. 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 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 ...

, 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 (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

. 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, aims to create an environment that supports equal opportunity for individuals and groups that form a society. ** Inclusion (disability rights), promotion of people with disabiliti ...

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. The ...

. The age of the amber deposits in

Kachin State Kachin State ( my, ကချင်ပြည်နယ်; Kachin: ), also known by the endonym Kachinland, is the northernmost state of Myanmar. It is bordered by China to the north and east (Tibet and Yunnan, specifically and respectively); Sh ...

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 ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

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

Myitkyina Myitkyina (, ; (Eng; ''mitchinar'') Jinghpaw: ''Myitkyina'', ) is the capital city of Kachin State in Myanmar (Burma), located from Yangon, and from Mandalay. In Burmese it means "near the big river", and Myitkyina is on the west bank of the ...

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, and several satellite campuses, research and educational centers, medical centers, and classes across the state of Kansas. Tw ...

Lawrence, Kansas Lawrence is the county seat of Douglas County, Kansas, 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, between the Kansas River, Kansas and Waka ...

. Engel's 2011

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 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 editor-in-chief is Terry Erwin (Smithsonian Institution). It is published by Pensoft Publ ...

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

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 ...

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, 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 ...

''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 Theodore Dru Alison Cockerell (1866–1948) was an American zoology, zoologist, born at Norwood, England, and brother of Sydney Cockerell. He was educated at the Middlesex Hospital Medical School, and then studied botany in the field in Colorad ...

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 (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 ...

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 insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwin ...

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 ea ...

, and

tegmina A tegmen (plural: ''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 an ...

, 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