{{italic title}}{{Taxobox

| name = ''Ichthyoconodon''

| fossil_range = {{fossil range|145|139}}

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| regnum = [[Animalia]]

| phylum = [[Chordata]]

| subphylum = [[Vertebrata]]

| classis = [[Mammalia]]

| ordo = [[Eutriconodonta]]

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| familia = [[Triconodontidae]]

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| subfamilia = [[Alticonodontinae]]

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| genus = †'''''Ichthyoconodon'''''

| genus_authority = Sigogneau-Russell, 1995

| type_species = ''Ichthyoconodon jaworowskorum''

| type_species_authority = Sigogneau-Russell, 1995

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'''''Ichthyoconodon''''' ("fish cone tooth") is an extinct genus of [[Theriimorpha|theriimorph]] mammal from the [[Lower Cretaceous]] of [[Morocco]]. Usually considered an [[eutriconodont]], it is notable for its oceanic location and atypical shape, indicative of potentially unusual ecological niches; some researchers think that it may be the first [[marine mammal]],<ref name="Sigogneau-Russell 1995">{{cite journal|last=Sigogneau-Russell|first= Denise|year=1995|title= Two possibly aquatic triconodont mammals from the Early Cretaceous of Morocco|journal= Acta Palaeontologica Polonica|volume=40|issue=2|pages=149-162|url=}}</ref> or part of a bizarre clade of flying mammals.<ref name="Gaetano & Rougier 2011">{{cite journal|last1=Gaetano|first1=Leandro C.|last2=Rougier|first2=Guillermo W.|title=New materials of ''Argentoconodon fariasorum'' (Mammaliaformes, Triconodontidae) from the Jurassic of Argentina and its bearing on triconodont phylogeny|journal=Journal of Vertebrate Paleontology|year=2011|volume=31|issue=4|pages=829–843|doi=10.1080/02724634.2011.589877}}</ref>


''Ichthyoconodon'' is known primarily from isolated teeth from [[Anoual Syncline]] sediments of [[Morocco]], in particular strata thought to date to the [[Berriasian]]. These teeth, mostly molars, possess many synapomorphies associated with [[Triconodontidae|triconodontid]] eutriconodonts, but its cusps are notoriously sharp for the group's standards and are rather specialised. They belong to animal in life possibly as large as a [[platypus]].


''Ichthyoconodon'' has been found to be a eutriconodont, though the degree of speciation has been noted as being difficult to assess its status as such.<ref name="Sigogneau-Russell 1995"/> Rose et al. found some skepticism about a eutriconodont identity,<ref>Rose, K.D., Cifelli, R.L. & Lipka, T.R. (2001) Second triconodont dentary from the Early Cretaceous of Maryland. Journal of Vertebrate Paleontology Volume 21. pp. 628–632.</ref> and some studies have suggested an identity not even as a mammal, but as a [[pterosaur]],<ref name="auto1">Kielan-Jaworowska, R. L. Cifelli, and Z.-X. Luo. 2004. Mammals from the age of dinosaurs: Origins, evolution, and structure. Columbia University Press, New York 1-630 [R. Whatley/R. Whatley/R. Whatley]</ref> but most recent phylogenetic studies favour a eutriconodont identity.<ref>Mikko Haaramo (2007) Mikko's Phylogeny Archive. Acceso: 2 de noviembre de 2007.</ref><ref name="auto1"/><ref name="Gaetano & Rougier 2011"/>

The most recent phylogenetic studies favour a close relationship with ''[[Volaticotherium]]'' and ''[[Argentoconodon]]'' within the [[Triconodontidae|triconodontid]] clade [[Alticonodontinae]]''.<ref name="Gaetano & Rougier 2011"/>


''Ichthyoconodon'''s teeth are located in marine deposits, alongside taxa like [[Hybodontidae|hybodontid]] [[sharks]], [[Ornithocheiridae|ornithocheirid]] [[pterosaurs]],<ref>Wilton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. ISBN 0691150613.</ref> [[ray-finned fish]] and [[sea turtles]], as well as several terrestrial taxa like [[theropods]].<ref>{{cite web|url=|title=Fossilworks: Gateway to the Paleobiology Database|}}</ref> Unlike other mammal teeth, including other contemporary teeth such as those of ''[[Hahnodon]]'', which show some degree of degradation, ''Ichthyoconodon'' teeth are not significantly modified, ruling out the possibility that the animal was carried over from river deposits. This means that the mammal either died ''in situ'' or was only carried over for a short distance.<ref name="Sigogneau-Russell 1995"/>

Because the teeth of ''Ichthyoconodon'' are rather sharp and convergent in some details to the teeth of piscivorous mammals like otters and seals, some researchers have suggested that it was a marine mammal. If this is the case, it is by far the earliest known mammal species to have adapted to live in the sea. The [[Jurassic]] and [[Cretaceous]] [[Docodonta|docodonts]] like ''[[Castorocauda]]'' and ''[[Haldanodon]]'', [[Early Cretaceous]] [[monotremes]] and the [[Late Cretaceous]] ''[[Didelphodon]]'' have also specialised for an aquatic lifestyle, but ''Ichthyoconodon'' would have been the only known Mesozoic mammal to have foraged in the sea.

Alternatively, ''Ichthyoconodon'' may have been volant, based on its relationship with the gliding ''[[Volaticotherium]]'' and the possibly also volant ''[[Argentoconodon]]''. The presence of ''[[Argentoconodon]]'' in [[South America]], ''[[Volaticotherium]]'' in [[Asia]] and ''Ichthyoconodon'' in [[North Africa]] in such a relatively close span of time suggests that there may have been a clade of Jurassic-Early Cretaceous flying triconodonts.<ref name="Gaetano & Rougier 2011"/>

Either situation would have been exceptional for a Mesozoic mammal, further adding to the variety of ecological niches these animals occupied.



[[Category:Extinct mammals]]


[[Category:Cretaceous mammals]]

[[Category:Mesozoic mammals of Africa]]

[[Category:Animal flight]]

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