Capinatator

{{Short description|Cambrian genus of chaetognath}} {{Speciesbox | fossil_range = [[Cambrian]] ([[Wuliuan]]) {{fossil range|Wuliuan|Wuliuan|}} | image = Capinatator.png | image_caption = A reconstruction of ''Capinatator praetermissus'' | genus = Capinatator | species = praetermissus | authority = Briggs and Caron, 2017<ref name=capinatator>{{Cite journal | doi=10.1016/j.cub.2017.07.003| pmid=28781052| title=A Large Cambrian Chaetognath with Supernumerary Grasping Spines| journal=Current Biology| volume=27| issue=16| pages=2536–2543.e1| year=2017| last1=Briggs| first1=Derek E.G| last2=Caron| first2=Jean-Bernard| doi-access=free| bibcode=2017CBio...27E2536B}}</ref> }}

'''''Capinatator praetermissus''''' is an [[extinct]] [[arrow worm]] from the [[Burgess Shale]] [[lagerstätte]].

== Description ==

''Capinatator'' has an unusually large amount of spines in its jaw apparatus, with over 25 on each half. These spines are arranged in arcs like modern [[chaetognatha|chaetognaths]], although unlike the modern types no posterior or anterior teeth are observed. The body tapers anteriorly and posteriorly, but unlike all modern arrow worms except the atypical ''[[Bathybelos]]'', a neck is observed separating the head and trunk. The tail is very small, with the anus almost at the posterior end. Unusually no fins are known, although they likely decayed prior to fossilisation. A dark line is preserved running down the middle of the animal, likely the pharynx and intestine. Thin fibres oriented lengthwise along the body are interpreted as remnants of longitudinal muscles, and poorly defined dark areas near the tail are likely ovaries. The amount of spines in the apparatus seemingly increases with size, as the smallest specimens only have around five on each side. A possible hood is also preserved, however this is unclear. The body is roughly {{Convert|10|cm}} long, placing it as one of the largest known chaetognaths alongside ''[[Pseudosagitta gazellae]]''.<ref name=capinatator/> (While claims of {{Convert|15|cm}} long chaetognaths have been recorded,<ref>{{cite book |last1=Margulis |first1=Lynn |last2=Chapman |first2=Michael J. |title=Kingdoms & domains: an illustrated guide to the phyla of life on Earth |date=2009 |publisher=Academic Press/Elsevier |location=Amsterdam Boston |isbn=978-0-12-373621-5 |edition=4th}}</ref> these are uncited)

== Palaeobiology ==

The strengthened tips of its spines likely helped capture prey, which was enclosed by the two halves of the apparatus moving together. Its large size likely represents a stage before chaetognaths became planktonic, with them starting out as large [[nekton]]ic predators. In addition, the lack of any teeth suggests these are a derived trait, possibly evolved from some of the numerous spines due to their near-identical composition in modern arrow worms. The lack of transverse muscles and small tail suggests ''Capinatator'' was likely pelagic.<ref name=capinatator/>

== Etymology ==

The genus name ''Capinatator'' derives from the Latin words ''capio'' (“to grasp”) and ''natator'' (“swimmer”) in reference to its predatory nature. The species name ''praetermissus'' translates to “overlooked” in reference to the length of time between discovery and naming, with some specimens having been discovered over 30 years prior.<ref name=capinatator/>

==References== {{Reflist}}

[[Category:Cambrian invertebrates]] [[Category:Fossils of British Columbia]] [[Category:Burgess Shale animals]] [[Category:Chaetognatha]] [[Category:Fossil taxa described in 2017]] [[Category:Cambrian genus extinctions]]