Editing Ostracod (section)

==Fossils==
[[File:HerrmanninaSilurianEstonia.jpg|thumb|The large ostracod ''Herrmannina'' from the [[Silurian]] (Ludlow) Soeginina Beds (Paadla Formation) on eastern [[Saaremaa]] Island, [[Estonia]]]]
Ostracods are "by far the most common arthropods in the fossil record"<ref>{{cite journal |author=[[David J. Siveter]] |author2=[[Derek E. G. Briggs]] |author3=Derek J. Siveter |author4=Mark D. Sutton |year=2010 |title=An exceptionally preserved myodocopid ostracod from the Silurian of Herefordshire, UK |journal=[[Proceedings of the Royal Society B]] |volume=277 |issue=1687 |pages=1539–1544 |doi=10.1098/rspb.2009.2122 |pmid=20106847 |pmc=2871837}}</ref> with fossils being found from the early [[Ordovician]] to the present. An outline [[microfauna]]l zonal scheme based on both [[Foraminifera]] and Ostracoda was compiled by M. B. Hart.<ref>{{cite journal |author=Malcolm B. Hart |year=1972 |title=A correlation of the macrofaunal and microfaunal zonations of the Gault Clay in southeast England |journal=[[Geological Journal]] |issue=Special Issue 5 |pages=267–288 |editor1=R. Casey |editor2=P. F. Rawson}}</ref> Freshwater ostracods have even been found in [[Baltic amber]] of [[Eocene]] age, having presumably been washed onto trees during floods.<ref>{{cite journal <!-- |book-title=Evolution and Diversity of Ostracoda. Theme 2 of the 14th International Symposium on Ostracoda (ISO 2001), Shizuoka, Japan --> |editor1=Noriyuki Ikeya |editor2=Akira Tsukagoshi |editor3=David J. Horne |title=Preface: The phylogeny, fossil record and ecological diversity of ostracod crustaceans |journal=[[Hydrobiologia]] |volume=538 |issue=1–3 |year=2005 |doi=10.1007/s10750-004-4914-z |pages=vii–xiii |author1=Noriyuki Ikeya, Akira Tsukagoshi  |author2=David J. Horne |s2cid=43836792 |name-list-style=amp }}</ref>

Ostracods have been particularly useful for the [[biostratigraphy|biozonation]] of marine strata on a local or regional scale, and they are invaluable indicators of paleoenvironments because of their widespread occurrence, small size, easily preservable, generally moulted, calcified bivalve carapaces; the valves are a commonly found [[microfossil]].

A find in [[Queensland, Australia]], in 2013, announced in May 2014, at the [[Bicentennary of Australia|Bicentennary]] Site in the [[Australian Fossil Mammal Sites (Riversleigh)|Riversleigh]] [[World Heritage]] area, revealed both male and female specimens with very well preserved soft tissue. This set the [[Guinness World Record]] for the oldest penis.<ref>[http://www.guinnessworldrecords.com/world-records/oldest-penis Oldest penis]:<br/>''The oldest fossilised penis discovered to date dates back around 100 million years. It belongs to a crustacean called an ostracod, discovered in Brazil and measuring just 1mm across.''</ref> Males had observable sperm that is the oldest yet seen and, when analysed, showed internal structures and has been assessed as being the largest sperm (per body size) of any animal recorded. It was assessed that the fossilisation was achieved within several days, due to phosphorus in the bat droppings of the cave where the ostracods were living.<ref>[http://www.abc.net.au/science/articles/2014/05/14/4003454.htm World's oldest sperm 'preserved in bat poo'], Anna Salleh, [[ABC Online]] Science, 14 May 2014, accessed 15 May 2014</ref>