Editing Seahorse (section)

==Evolution and fossil record==
Anatomical evidence, supported by molecular, physical, and genetic evidence, demonstrates that seahorses are highly modified [[pipefish]]. The fossil record of seahorses, however, is very sparse. The best known and best studied fossils are specimens of ''[[Hippocampus guttulatus]]'' (though literature more commonly refers to them under the synonym of ''H.&nbsp;ramulosus''), from the [[Marecchia River]] formation of [[Rimini Province]], Italy, dating back to the [[Lower Pliocene]], about 3''&nbsp;''million years ago. The earliest known seahorse fossils are of two pipefish-like species, ''[[Hippocampus sarmaticus|H.&nbsp;sarmaticus]]'' and ''[[Hippocampus slovenicus|H.&nbsp;slovenicus]]'', from the [[coprolite|coprolitic]] horizon of [[Tunjice]] Hills, a [[middle Miocene]] [[lagerstätte]] in [[Slovenia]] dating back about 13''&nbsp;''million years.<ref>{{cite journal |author1=Žalohar J. |author2=Hitij T. |author3=Križnar M. |year=2009 |title=Two new species of seahorses (Syngnathidae, ''Hippocampus'') from the Middle Miocene (Sarmatian) Coprolitic Horizon in Tunjice Hills, Slovenia: The oldest fossil record of seahorses |journal=Annales de Paléontologie |volume=95 |issue=2 |pages=71–96 |doi=10.1016/j.annpal.2009.03.002|bibcode=2009AnPal..95...71Z }}</ref>

[[Molecular clock|Molecular dating]] implies that pipefish and seahorses diverged during the Late [[Oligocene]]. This has led to speculation that seahorses evolved in response to large areas of shallow water, newly created as the result of [[tectonic]] events. The shallow water would have allowed the expansion of seagrass habitats that served as [[camouflage]] for the seahorses' upright posture.<ref name=Teske-2009>{{cite journal |author1=Teske PR |author2=Beheregaray LB |title=Evolution of seahorses' upright posture was linked to Oligocene expansion of seagrass habitats |journal=Biol. Lett. |volume=5 |issue=4 |pages=521–3 |year=2009 |doi=10.1098/rsbl.2009.0152 |pmc=2781918 |pmid=19451164}}</ref> These tectonic changes occurred in the western [[Pacific Ocean]], pointing to an origin there, with molecular data suggesting two later, separate invasions of the [[Atlantic Ocean]].<ref name=Teske-2004>{{cite journal |doi=10.1016/S1055-7903(03)00214-8 |author1=Teske PR |author2=Cherry MI |author3=Matthee CA |title=The evolutionary history of seahorses (Syngnathidae: Hippocampus): molecular data suggest a West Pacific origin and two invasions of the Atlantic Ocean |journal=Mol Phylogenet Evol |volume=30 |issue=2 |pages=273–86 |year=2004 |pmid=14715220 |bibcode=2004MolPE..30..273T }}</ref> In 2016, a study published in ''Nature'' found the seahorse genome to be the most rapidly evolving fish genome studied so far.<ref name=nature20595>{{cite journal |title=The seahorse genome and the evolution of its specialized morphology |journal=Nature |date=14 December 2016 |volume=540 |issue=7633 |doi=10.1038/nature20595 |pmid=27974754 |bibcode=2016Natur.540..395L |pages=395–399 |last1=Lin |first1=Qiang |last2=Fan |first2=Shaohua |last3=Zhang |first3=Yanhong |last4=Xu |first4=Meng |last5=Zhang |first5=Huixian |last6=Yang |first6=Yulan |last7=Lee |first7=Alison P |last8=Woltering |first8=Joost M |last9=Ravi |first9=Vydianathan |last10=Gunter |first10=Helen M |last11=Luo |first11=Wei |last12=Gao |first12=Zexia |last13=Lim |first13=Zhi Wei |last14=Qin |first14=Geng |last15=Schneider |first15=Ralf F |last16=Wang |first16=Xin |last17=Xiong |first17=Peiwen |last18=Li |first18=Gang |last19=Wang |first19=Kai |last20=Min |first20=Jiumeng |last21=Zhang |first21=Chi |last22=Qiu |first22=Ying |last23=Bai |first23=Jie |last24=He |first24=Weiming |last25=Bian |first25=Chao |last26=Zhang |first26=Xinhui |last27=Shan |first27=Dai |last28=Qu |first28=Hongyue |last29=Sun |first29=Ying |last30=Gao |first30=Qiang |last31=Huang |first31=Liangmin |last32=Shi |first32=Qiong |last33=Meyer |first33=Axel |last34=Venkatesh |first34=Byrappa |pmc=8127814 |display-authors=6 |doi-access=free }}</ref>

The evolution of seahorses from pipefish may have been an adaptation related to the biomechanics of prey capture. The unique posture of the seahorse allows them to capture small shrimps at larger distances than the pipefish is capable of.<ref>{{Cite journal |last1=Van Wassenbergh |first1=Sam |last2=Roos |first2=Gert |last3=Ferry |first3=Lara |date=2011-01-25 |title=An adaptive explanation for the horse-like shape of seahorses |journal=Nature Communications |volume=2 |issue=1 |pages=164 |doi=10.1038/ncomms1168 |pmid=21266964 |bibcode=2011NatCo...2..164V |issn=2041-1723 |doi-access=free}}</ref>