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{{Short description|Genus of extinct elasmobranch from the Late Cretaceous period}}
{{Automatic taxobox
{{Automatic taxobox
| fossil_range = [[Late Cretaceous]], <br>{{fossilrange|93}} [[Turonian]]
| fossil_range = [[Late Cretaceous]], {{fossilrange|93}}
| image = Aquilolamna milarcae restoration.jpg
| image_caption = Restoration of ''A. milarcae''
| display_parents = 2
| display_parents = 2
| parent_authority = Vullo ''et al.'', 2021
| taxon = Aquilolamna
| taxon = Aquilolamna
| authority = Vullo, Frey, Ifrim, González González, Stinnesbeck, & Stinnesbeck, 2021
| authority = Vullo ''et al.'', 2021
| type_species = '''''Aquilolamna milarcae'''''
| type_species = {{extinct}}'''''Aquilolamna milarcae'''''
| type_species_authority = Vullo, Frey, Ifrim, González González, Stinnesbeck, & Stinnesbeck, 2021
| type_species_authority = Vullo ''et al.'', 2021
}}
}}


'''''Aquilolamna''''' ("[[eagle]] shark") is an [[Extinction|extinct]] [[genus]] of [[shark]]-like [[Elasmobranchii|elasmobranch]] from the [[Late Cretaceous]] ([[Turonian]])-aged [[Agua Nueva Formation]] of [[Mexico]]. It is currently known to contain only one [[species]], '''''A. milarcae''''', and it is classified in its own [[Family (biology)|family]] '''Aquilolamnidae''', which has been tentatively assigned to the [[Lamniformes|mackerel sharks]].<ref name=":0">{{Cite journal|last=Vullo|first=Romain|last2=Frey|first2=Eberhard|last3=Ifrim|first3=Christina|last4=González|first4=Margarito A. González|last5=Stinnesbeck|first5=Eva S.|last6=Stinnesbeck|first6=Wolfgang|date=2021-03-19|title=Manta-like planktivorous sharks in Late Cretaceous oceans|url=https://science.sciencemag.org/content/371/6535/1253|journal=Science|language=en|volume=371|issue=6535|pages=1253–1256|doi=10.1126/science.abc1490|issn=0036-8075}}</ref>
'''''Aquilolamna''''' is an [[Extinction|extinct]] [[genus]] of [[shark]]-like [[Elasmobranchii|elasmobranch]] from the [[Late Cretaceous]] ([[Turonian]])-aged [[Agua Nueva Formation]] of [[Mexico]]. It is currently known to contain only one [[species]], '''''A. milarcae''''', also known as the '''eagle shark''', and it is classified in its own [[Family (biology)|family]] '''Aquilolamnidae''', which has been tentatively assigned to the [[Lamniformes|mackerel sharks]].<ref name=":0">{{Cite journal|last1=Vullo|first1=Romain|last2=Frey|first2=Eberhard|last3=Ifrim|first3=Christina|last4=González|first4=Margarito A. González|last5=Stinnesbeck|first5=Eva S.|last6=Stinnesbeck|first6=Wolfgang|date=2021-03-19|title=Manta-like planktivorous sharks in Late Cretaceous oceans|url=https://www.science.org/doi/10.1126/science.abc1490|journal=Science|language=en|volume=371|issue=6535|pages=1253–1256|doi=10.1126/science.abc1490|pmid=33737486|s2cid=232271254|issn=0036-8075}}</ref><ref>{{Cite web|title=The 'eagle shark' that glided through ancient seas|url=https://phys.org/news/2021-03-discovery-winged-shark-cretaceous-seas.html|access-date=2021-03-19|website=phys.org|language=en}}</ref>


== Taxonomy ==
== Taxonomy ==
While ''Aquilolamna'' is thought to be an elasmobranch, its taxonomy is disputed, as despite having an very well-preserved specimen, no teeth are known to have been preserved, which are important for determining the taxonomic affinities of fossil sharks; they are thought to have been dislodged when the fossilized individual died, although they could be preserved deeper in the matrix. Potential skin impressions preserved with the fossil could potentially be just fossilized [[Biofilm|bacterial mats]]. It was tentatively assigned to [[Lamniformes]] by the paper that described it based on some morphological similarities, but due to its extremely unusual features, other paleontologists have reservations about classifying it as such, and future research may be required.<ref name=":1">{{Cite web|date=2021-03-18|title=Shark-like fossil with manta 'wings' is unlike anything seen before|url=https://www.nationalgeographic.com/science/article/shark-like-fossil-with-manta-wings-is-unlike-anything-seen-before|access-date=2021-03-18|website=Science|language=en}}</ref> However, it has been suspected that ''Aquilolamna'' may have been closely allied with ''[[Cretomanta]]'', an extinct [[Neoselachii|neoselachian]] of uncertain taxonomic identity described in 1990 from teeth found in [[Texas]] (with further remains found in [[Canada]] and [[Colorado]]), which lived around the same time as ''Aquilolamna''. Both genera may even belong to the same family.<ref>{{Cite web|date=2021-03-18|title=Meet Aquilolamna, a shark wider than it is long|url=https://www.abc.net.au/news/science/2021-03-19/long-winged-shark-aquilolamna-cretaceous-fossil-palaeontology/100014976|access-date=2021-03-18|website=www.abc.net.au|language=en-AU}}</ref><ref>{{Cite web|title=Fossilworks: Cretomanta|url=http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=121374|access-date=2021-03-18|website=fossilworks.org}}</ref>
While ''Aquilolamna'' is thought to be an elasmobranch, its taxonomy is disputed as, despite the [[holotype]] being a well-preserved body fossil, no teeth are known, which are important for determining the [[Affinity (taxonomy)|taxonomic affinities]] of fossil sharks; they are thought to have been dislodged when the individual died, although they could be preserved deeper in the matrix. Potential skin impressions preserved with the fossil could potentially be just fossilized [[Biofilm|bacterial mats]]. It was tentatively assigned to [[Lamniformes]] in its original description based on some morphological similarities to other members of the family. However, due to its extremely unusual features, other paleontologists have reservations about classifying it as such, and future research may be required.<ref name=":1">{{Cite web|date=2021-03-18|title=Shark-like fossil with manta 'wings' is unlike anything seen before|url=https://www.nationalgeographic.com/science/article/shark-like-fossil-with-manta-wings-is-unlike-anything-seen-before|archive-url=https://web.archive.org/web/20210318180921/https://www.nationalgeographic.com/science/article/shark-like-fossil-with-manta-wings-is-unlike-anything-seen-before/|url-status=dead|archive-date=March 18, 2021|access-date=2021-03-18|website=Science|language=en}}</ref> It has also been suspected that ''Aquilolamna'' may have been closely allied with ''[[Cretomanta]]'', an extinct [[Neoselachii|neoselachian]] of [[Incertae sedis|uncertain taxonomic affinity]] described in 1990 from teeth found in [[Texas]] (with further remains found in [[Canada]] and [[Colorado]]). ''Cretomanta'' lived around the same time as ''Aquilolamna'' and, given their possible similarities, both genera may belong to the same (unknown) family.<ref>{{Cite web|date=2021-03-18|title=Meet Aquilolamna, a shark wider than it is long|url=https://www.abc.net.au/news/science/2021-03-19/long-winged-shark-aquilolamna-cretaceous-fossil-palaeontology/100014976|access-date=2021-03-18|website=www.abc.net.au|language=en-AU}}</ref><ref>{{Cite web|title=Fossilworks: Cretomanta|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=121374|access-date=17 December 2021|website=fossilworks.org}}</ref>


== Description ==
== Description ==
It displays an array of extremely unusual adaptations that make it unlike any known species of shark, living or extinct. It had a torpedo-shaped body and tail similar to that of most sharks, but also had a pair of extremely long, winglike [[Fish fin|pectoral fins]] that made its body wider than it was long. These, combined with its broad head, have lead to the hypothesis that ''Aquilolamna'' was a [[Planktivore|planktivorous]] [[Filter feeder|filter-feeder]], marking a form of [[convergent evolution]] with [[Manta ray|manta rays]], which appeared millions of years later in the fossil record. Unlike manta rays, which "fly" through the water by flapping their fins, ''Aquilolamna'' may have instead steadily "glided" through the water with the help of its slender pectoral fins, and propelled itself with its tail.<ref name=":0" /><ref name=":2">{{Cite news|last=Dunham|first=Will|date=2021-03-18|title=Bizarre ancient shark glided through the sea with lengthy wing-like fins|language=en|work=Reuters|url=https://www.reuters.com/article/us-science-shark-idUSKBN2BA2J4|access-date=2021-03-18}}</ref>
''Aquilolamna'' displays an array of extremely unusual adaptations that make it unlike any living or extinct species of shark. It had a torpedo-shaped body and tail similar to that of most sharks, but also had a pair of extremely long, winglike [[Fish fin|pectoral fins]] whose width from tip to tip (1.90 meters) were wider than [[fish measurement|it was long]] (1.65 meters).<ref name="SciTechDaily">{{cite web |url=https://scitechdaily.com/discovery-of-a-bizarre-winged-eagle-shark-in-the-cretaceous-seas/ |website=SciTechDaily |access-date=8 September 2022|title=Discovery of a Bizarre, Winged "Eagle Shark" in the Cretaceous Seas}}</ref> These, combined with its broad head, have led to the hypothesis that ''Aquilolamna'' was a [[Planktivore|planktivorous]] [[Filter feeder|filter-feeder]], suggesting a form of [[convergent evolution]] with a [[manta ray]]-like body plan, which appeared millions of years later in the fossil record. Unlike manta rays, which "fly" through the water by flapping their fins, ''Aquilolamna'' may have instead steadily "glided" through the water with the help of its slender pectoral fins, and propelled itself with its tail.<ref name=":0" /><ref name=":2">{{Cite news|last=Dunham|first=Will|date=2021-03-18|title=Bizarre ancient shark glided through the sea with lengthy wing-like fins|language=en|work=Reuters|url=https://www.reuters.com/article/us-science-shark-idUSKBN2BA2J4|access-date=2021-03-18}}</ref>
[[File:AquilolamnaMilarcae.jpg|thumb|222x222px|Paleoart depicting a small school of Aquilolamna]]


== Discovery ==
== Discovery ==
It was described from a single extremely well-preserved specimen, containing a fully-preserved skeleton and potential skin impressions, recovered in 2012 by an unknown quarry worker in [[Vallecillo Municipality|Vallecillo]] in the [[Mexico|Mexican]] state of [[Nuevo León]]. The specimen came to the attention of local [[Paleontology|paleontologist]] Margarito González González, who collected and prepared the specimen. Over the coming years, it received increasing attention at paleontological conferences, and was finally described in 2021.<ref name=":1" />
It was described from a single extremely well-preserved specimen, containing a fully-preserved skeleton and potential skin impressions, recovered in 2012 by an unknown quarry worker in [[Vallecillo Municipality|Vallecillo]] in the [[Mexico|Mexican]] state of [[Nuevo León]]. The specimen came to the attention of local teacher Margarito González González, who collected and prepared the specimen. Over the coming years, it received increasing attention at paleontological conferences, and was finally described in 2021.<ref name=":1" /> The paper describing the new species was problematic because the authors claimed the fossil was at a public museum, when in reality was part of the private collection of politician [[Mauricio Fernández Garza]]. The authors were also accused of scientific colonialism because they did not work with local paleontologists, as is mandated by the ''[[Instituto Nacional de Antropología e Historia]],'' the national agency regulating paleontological research in Mexico.<ref>{{Cite web|last=Pérez Ortega|first=Rodrigo|date=15 April 2021|title=This ancient shark fossil is exquisite. But some researchers wonder if they'll be able to study it|url=https://www.science.org/content/article/ancient-shark-fossil-exquisite-some-researchers-wonder-if-they-ll-be-able-study-it|access-date=2021-11-18|website=www.science.org|language=en}}</ref>


== Paleoecology ==
== Paleoecology ==
[[File:Aquilolamna.png|thumb|''Aquilolamna'' - sketching]]
''Aquilolamna'' likely lived in a [[Pelagic zone|pelagic]] habitat during the [[Turonian]] period of the [[Late Cretaceous]], about 93 [[Myr|million years ago]]. It may have shared its habitat with [[Marine reptile|marine reptiles]], [[Ammonoidea|ammonites]], and various [[Osteichthyes|bony fishes]], with the top predator in the ecosystem being the large mackerel shark ''[[Cretoxyrhina]]''. ''Aquilolamna''<nowiki/>'s lineage may have went extinct following a decline in [[plankton]] populations brought about by [[ocean acidification]] from the [[Cretaceous–Paleogene extinction event]], with [[Eagle ray|mobulid]] rays and other [[Batoidea|batoids]] later filling in the [[ecological niche]] left by its extinction.<ref name=":0" /><ref name=":2" />
''Aquilolamna'' likely lived in a [[Pelagic zone|pelagic]] habitat during the [[Turonian]] period of the [[Late Cretaceous]], about 93 [[Myr|million years ago]]. The formation it was found in, the Agua Nueva, is thought to be composed of sediments deposited in the outer part of a shallow [[continental shelf]].<ref name=":3">{{Cite journal|date=2003-07-01|title=New Teleostei from the Agua Nueva Formation (Turonian), Vallecillo (NE Mexico)|url=https://www.sciencedirect.com/science/article/pii/S1631068303000642|journal=Comptes Rendus Palevol|language=en|volume=2|issue=5|pages=299–306|doi=10.1016/S1631-0683(03)00064-2|issn=1631-0683|last1=Blanco|first1=Alberto|last2=Cavin|first2=Lionel}}</ref> It may have shared its habitat with [[Marine reptile|marine reptiles]], such as the [[Polycotylidae|polycotylid]] ''[[Mauriciosaurus]]'', [[Ammonoidea|ammonites]], and various [[Osteichthyes|bony fishes]] such as the [[Ichthyodectiformes|ichthyodectiform]] ''[[Vallecillichthys]]'' and the [[Crossognathiformes|crossognathiforms]] ''[[Goulmimichthys]]'' and ''[[Araripichthys]]''.<ref name=":3" /> The top predator in the ecosystem was likely the large mackerel shark ''[[Cretoxyrhina]]''. ''Aquilolamna''<nowiki/>'s lineage may have gone extinct following a decline in [[plankton]] populations brought about by [[ocean acidification]] from the [[Cretaceous–Paleogene extinction event]], with [[Eagle ray|mobulid]] rays and other [[Batoidea|batoids]] later filling in the [[ecological niche]] left by its extinction.<ref name=":0" /><ref name=":2" />


== References ==
== References ==
{{Reflist}}
[[Category:Cretaceous sharks|?]]

[[Category:Shark genera|?]]
{{Taxonbar|from=Q106045176}}
[[Category:Cartilaginous fish genera]]

[[Category:Cretaceous sharks]]
[[Category:Prehistoric shark genera]]
[[Category:Prehistoric Lamniformes]]
[[Category:Late Cretaceous fish of North America]]
[[Category:Late Cretaceous fish of North America]]
[[Category:Fossils of Mexico]]
[[Category:Fossils of Mexico]]
[[Category:Cretaceous Mexico]]
[[Category:Fossil taxa described in 2021]]
[[Category:Fossil taxa described in 2021]]

Latest revision as of 06:22, 18 November 2024

Aquilolamna
Temporal range: Late Cretaceous, 93 Ma
Restoration of A. milarcae
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Lamniformes (?)
Family: Aquilolamnidae
Vullo et al., 2021
Genus: Aquilolamna
Vullo et al., 2021
Type species
Aquilolamna milarcae
Vullo et al., 2021

Aquilolamna is an extinct genus of shark-like elasmobranch from the Late Cretaceous (Turonian)-aged Agua Nueva Formation of Mexico. It is currently known to contain only one species, A. milarcae, also known as the eagle shark, and it is classified in its own family Aquilolamnidae, which has been tentatively assigned to the mackerel sharks.[1][2]

Taxonomy

[edit]

While Aquilolamna is thought to be an elasmobranch, its taxonomy is disputed as, despite the holotype being a well-preserved body fossil, no teeth are known, which are important for determining the taxonomic affinities of fossil sharks; they are thought to have been dislodged when the individual died, although they could be preserved deeper in the matrix. Potential skin impressions preserved with the fossil could potentially be just fossilized bacterial mats. It was tentatively assigned to Lamniformes in its original description based on some morphological similarities to other members of the family. However, due to its extremely unusual features, other paleontologists have reservations about classifying it as such, and future research may be required.[3] It has also been suspected that Aquilolamna may have been closely allied with Cretomanta, an extinct neoselachian of uncertain taxonomic affinity described in 1990 from teeth found in Texas (with further remains found in Canada and Colorado). Cretomanta lived around the same time as Aquilolamna and, given their possible similarities, both genera may belong to the same (unknown) family.[4][5]

Description

[edit]

Aquilolamna displays an array of extremely unusual adaptations that make it unlike any living or extinct species of shark. It had a torpedo-shaped body and tail similar to that of most sharks, but also had a pair of extremely long, winglike pectoral fins whose width from tip to tip (1.90 meters) were wider than it was long (1.65 meters).[6] These, combined with its broad head, have led to the hypothesis that Aquilolamna was a planktivorous filter-feeder, suggesting a form of convergent evolution with a manta ray-like body plan, which appeared millions of years later in the fossil record. Unlike manta rays, which "fly" through the water by flapping their fins, Aquilolamna may have instead steadily "glided" through the water with the help of its slender pectoral fins, and propelled itself with its tail.[1][7]

Paleoart depicting a small school of Aquilolamna

Discovery

[edit]

It was described from a single extremely well-preserved specimen, containing a fully-preserved skeleton and potential skin impressions, recovered in 2012 by an unknown quarry worker in Vallecillo in the Mexican state of Nuevo León. The specimen came to the attention of local teacher Margarito González González, who collected and prepared the specimen. Over the coming years, it received increasing attention at paleontological conferences, and was finally described in 2021.[3] The paper describing the new species was problematic because the authors claimed the fossil was at a public museum, when in reality was part of the private collection of politician Mauricio Fernández Garza. The authors were also accused of scientific colonialism because they did not work with local paleontologists, as is mandated by the Instituto Nacional de Antropología e Historia, the national agency regulating paleontological research in Mexico.[8]

Paleoecology

[edit]
Aquilolamna - sketching

Aquilolamna likely lived in a pelagic habitat during the Turonian period of the Late Cretaceous, about 93 million years ago. The formation it was found in, the Agua Nueva, is thought to be composed of sediments deposited in the outer part of a shallow continental shelf.[9] It may have shared its habitat with marine reptiles, such as the polycotylid Mauriciosaurus, ammonites, and various bony fishes such as the ichthyodectiform Vallecillichthys and the crossognathiforms Goulmimichthys and Araripichthys.[9] The top predator in the ecosystem was likely the large mackerel shark Cretoxyrhina. Aquilolamna's lineage may have gone extinct following a decline in plankton populations brought about by ocean acidification from the Cretaceous–Paleogene extinction event, with mobulid rays and other batoids later filling in the ecological niche left by its extinction.[1][7]

References

[edit]
  1. ^ a b c Vullo, Romain; Frey, Eberhard; Ifrim, Christina; González, Margarito A. González; Stinnesbeck, Eva S.; Stinnesbeck, Wolfgang (2021-03-19). "Manta-like planktivorous sharks in Late Cretaceous oceans". Science. 371 (6535): 1253–1256. doi:10.1126/science.abc1490. ISSN 0036-8075. PMID 33737486. S2CID 232271254.
  2. ^ "The 'eagle shark' that glided through ancient seas". phys.org. Retrieved 2021-03-19.
  3. ^ a b "Shark-like fossil with manta 'wings' is unlike anything seen before". Science. 2021-03-18. Archived from the original on March 18, 2021. Retrieved 2021-03-18.
  4. ^ "Meet Aquilolamna, a shark wider than it is long". www.abc.net.au. 2021-03-18. Retrieved 2021-03-18.
  5. ^ "Fossilworks: Cretomanta". fossilworks.org. Retrieved 17 December 2021.
  6. ^ "Discovery of a Bizarre, Winged "Eagle Shark" in the Cretaceous Seas". SciTechDaily. Retrieved 8 September 2022.
  7. ^ a b Dunham, Will (2021-03-18). "Bizarre ancient shark glided through the sea with lengthy wing-like fins". Reuters. Retrieved 2021-03-18.
  8. ^ Pérez Ortega, Rodrigo (15 April 2021). "This ancient shark fossil is exquisite. But some researchers wonder if they'll be able to study it". www.science.org. Retrieved 2021-11-18.
  9. ^ a b Blanco, Alberto; Cavin, Lionel (2003-07-01). "New Teleostei from the Agua Nueva Formation (Turonian), Vallecillo (NE Mexico)". Comptes Rendus Palevol. 2 (5): 299–306. doi:10.1016/S1631-0683(03)00064-2. ISSN 1631-0683.