''Zigrasolabis'' 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 family

Labiduridae Labiduridae, whose members are known commonly as striped earwigs, is a relatively large family of earwigs in the suborder Neodermaptera. Taxonomy The family contains a total of approximately 72 species, spread across seven genera in three subfa ...

known from

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 a single described species, ''Zigrasolabis speciosa''.

History and classification

''Zigrasolabis'' is known from a group of fossils, 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 JZC-Bu232, along with two

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 (biology), isotype ...

s and a partial specimen. The specimens are composed of three fully complete adult female earwigs, and the partial female, which have been preserved as

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 ...

s in a single 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 ...

in northernmost Burma is understood to be at least 100 million years old, placing them in the Albian age of the Cretaceous. As of 2014, Burmese amber has been

radiometrically dated Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

using U- Pb isotopes, yielding an age of approximately 99 million years old, close to the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

–

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 ...

boundary. At the time of description, the amber specimen was residing in the private collection of James Zigras and only available for study through 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 ...

. The ''Zigrasolabis'' type specimens, recovered from amber bearing outcrops in

, were first studied by paleoentomologists 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 ...

, and David Grimaldi of the American Museum of Natural History. Engel and Grimaldi's 2014

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 journal '' Novitates Paleoentomologicae''. The genus name ''Zigrasolabis'' was coined by Engel and Grimaldi 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 ...

word ''labis'', which means "forceps" and Zigras in honor of James Zigras. 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 ...

''speciosa'' is from the Latin word ''speciosus'', which translate as "splendid". ''Zigrasolabis'' is one of six described earwig species found in Burmese amber. A second species, '' Toxolabis zigrasi'' was also described by Engel and Grimaldi in 2014 paper. Two species '' Astreptolabis ethirosomatia'' and '' Tytthodiplatys mecynocercus'' were described by Engel in the same 2011 paper, while '' Burmapygia resinata'' was described by Engel and David Grimaldi in 2004, with the last species '' Myrrholabia electrina'' first described by Theodore Cockerell in 1920.

Description

Female ''Zigrasolabis'' have and overall coloration that appears to be mat brown to dark brown, lightening on the legs and mouth parts. The females range between approximately in length when the cerci are included. The bodies are only sparsely 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 ...

, which are not thickened enough to be chaetulose. The antennae have a slightly wide scape and are at least fourteen

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 ...

long, though both the holotype and the paratypes have incomplete antennae. 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 which cover the first segments of the abdomen. The hind wings are present, but due to positioning of the tegma, are mostly obscured, though the tips extend beyond the tegma. The slender cerci are tubular and straight, tapering along the length to sharp points at the ends.

References

{{Taxonbar, from=Q18922566 Dermaptera genera Cretaceous insects Fossil taxa described in 2014 Cretaceous insects of Asia Burmese amber Fossils of Myanmar Taxa named by Michael S. Engel