Arthropod gap

{{Short description|Gap in evolutionary biology}}

The arthropod gap, also sometimes known as the hexapoda gap,{{cite web

|url=http://www.abc.net.au/science/articles/2012/08/02/3559075.htm

|title=Humble bug plugs gap in fossil record

|publisher=AFP

|date=2 August 2012}}{{cite journal|author=W. A. Shear|date=August 2012|url=https://www.researchgate.net/publication/230615755|title=Palaeontology: An insect to fill the gap|journal=Nature|volume=488|issue=7409|page=34-35|doi=10.1038/488034a}} is an apparent gap in the terrestrial arthropod (particular insect) fossil record noted in the study of evolutionary biology. The fossil gap occurs in the early Carboniferous, coinciding and extending past the Romer's gap for tetrapod vertebrates, who were newly arrived colonizers of land habitats.{{cite journal | first1=Jennifer A. | last1=Clack | first2=Carys E. | last2=Bennett | first3=David K. |last3=Carpenter | first4=Sarah J. | last4=Davies | first5=Nicholas C. | last5=Fraser | first6=Timothy I. | last6=Kearsey | first7=John E. A. | last7=Marshall | first8=David | last8=Millward | first9=Benjamin K. A. | last9=Otoo | first10=Emma J. | last10=Reeves | first11=Andrew J. | last11=Ross | first12=Marcello | last12=Ruta | first13=Keturah Z. | last13=Smithson | first14=Timothy R. | last14=Smithson | first15=Stig A. | last15=Walsh | date=2016 | title=Phylogenetic and environmental context of a Tournaisian tetrapod fauna | journal=Nature Ecology & Evolution |volume=1 | issue=1 | pages=0002 | doi=10.1038/s41559-016-0002 | pmid=28812555 | bibcode=2016NatEE...1....2C | s2cid=22421017 | url=http://nora.nerc.ac.uk/id/eprint/514391/1/109_2_merged_1475152841.pdf }}{{cite web|website=dead things|publisher=Discover|title=Tetrapod Triumph! Solving Mystery Of First Land Vertebrates|last=Tarlach|first=Gemma|date=December 5, 2016|url=http://blogs.discovermagazine.com/deadthings/2016/12/05/tetrapod-triumph-solving-mystery-of-first-land-vertebrates/#.WFurDJKSWRs|access-date=December 6, 2021|archive-date=August 3, 2019|archive-url=https://web.archive.org/web/20190803142850/http://blogs.discovermagazine.com/deadthings/2016/12/05/tetrapod-triumph-solving-mystery-of-first-land-vertebrates/#.WFurDJKSWRs|url-status=dead}}

The discovery of the Devonian insect species Strudiella devonica in 2012, and dated to 370 million years ago, reduces a previous gap of 45 million years in the evolutionary history of insects, from 385 million to 325 million years ago. However, its affinity as an insect is questioned later.{{Cite journal |last1=Hörnschemeyer |first1=Thomas |last2=Haug |first2=Joachim T. |last3=Bethoux |first3=Olivier |last4=Beutel |first4=Rolf G. |last5=Charbonnier |first5=Sylvain |last6=Hegna |first6=Thomas A. |last7=Koch |first7=Markus |last8=Rust |first8=Jes |last9=Wedmann |first9=Sonja |last10=Bradler |first10=Sven |last11=Willmann |first11=Rainer |date=2013 |title=Is Strudiella a Devonian insect? |url=https://www.nature.com/articles/nature11887 |journal=Nature |language=en |volume=494 |issue=7437 |pages=E3–E4 |doi=10.1038/nature11887 |pmid=23426326 |bibcode=2013Natur.494E...3H |s2cid=205232661 |issn=1476-4687}}