Atractosteus
{{Short description|Genus of fishes}}
{{Automatic taxobox
| image = Alligator Gar 10.JPG
| image_caption = Alligator gar
| name = Large gars
| fossil_range =
~Santonian–Present,
| taxon = Atractosteus
| authority = (Rafinesque, 1820)
| type_species = Esox spatula
| type_species_authority = Lacépède, 1803
| subdivision_ranks = Species
| subdivision = See text
| synonyms = * Lepisosteus (Atractosteus) Rafinesque 1820
- Litholepis Rafinesque 1818
| synonyms_ref = {{Cite web|last1=Froese|first1=R.|last2=Pauly|first2=D.|year=2017|title=Lepisosteidae |url=http://www.fishbase.se/Summary/FamilySummary.php?ID=34|website=FishBase version (02/2017)|accessdate=18 May 2017}}{{cite journal |last1=Van Der Laan |first1=Richard |last2=Eschmeyer |first2=William N. |last3=Fricke |first3=Ronald |title=Family-group names of Recent fishes |journal=Zootaxa |date=11 November 2014 |volume=3882 |issue=1 |pages=1–230 |doi=10.11646/zootaxa.3882.1.1 |pmid=25543675 |doi-access=free }}
}}
Atractosteus (from Greek atraktos (ἀτρακτὀς), 'spindle' and osteon (ὀστέον), 'bone'){{Cite book |last1=Jordan |first1=David Starr |url=https://books.google.com/books?id=G8DRAAAAMAAJ |title=The Fishes of North and Middle America: A Descriptive Catalogue of the Species of Fish-like Vertebrates Found in the Waters of North America, North of the Isthmus of Panama |last2=Evermann |first2=Barton Warren |date=1896 |publisher=U.S. Government Printing Office |language=en}} is a genus of gars in the family Lepisosteidae, with three extant species. It is one of two surviving gar genera alongside Lepisosteus.{{Cite journal |last1=Doran Brownstein |first1=Chase |last2=Yang |first2=Liandong |last3=Friedman |first3=Matt |last4=Near |first4=Thomas J |date=2022-12-20 |title=Phylogenomics of the Ancient and Species-Depauperate Gars Tracks 150 Million Years of Continental Fragmentation in the Northern Hemisphere |url=http://dx.doi.org/10.1093/sysbio/syac080 |journal=Systematic Biology |volume=72 |issue=1 |pages=213–227 |doi=10.1093/sysbio/syac080 |pmid=36537110 |issn=1063-5157}}
The three surviving species are all widely separated from one another, with A. spatula being found in the south-central United States, A. tropicus in southern Mexico and Central America, and A. tristoechus in Cuba. Although generally inhabiting fresh water, they are tolerant of marine conditions.
Evolution
The genus first appeared during the Santonian stage of the Late Cretaceous, having diverged from Lepisosteus earlier in the Cretaceous. It quickly achieved a widespread distribution throughout the rest of the Cretaceous, being known from North America, South America and Europe.{{Cite journal |last1=Alves |first1=Yuri Modesto |last2=Montefeltro |first2=Felipe Chinaglia |last3=Cidade |first3=Giovanne M. |date=2021-05-01 |title=New occurrences of Atractosteus (Ginglymodi: Lepisosteoidea: Lepisosteidae) from the Bauru Group (Upper Cretaceous, Brazil) and paleobiogeographic implications |url=https://www.sciencedirect.com/science/article/abs/pii/S0195667120304225 |journal=Cretaceous Research |volume=121 |pages=104735 |doi=10.1016/j.cretres.2020.104735 |issn=0195-6671}}{{Cite journal |last1=Szabó |first1=Márton |last2=Gulyás |first2=Péter |last3=Ősi |first3=Attila |date=2016-05-01 |title=Late Cretaceous (Santonian) Atractosteus (Actinopterygii, Lepisosteidae) remains from Hungary (Iharkút, Bakony Mountains) |url=https://www.sciencedirect.com/science/article/abs/pii/S0195667115301300 |journal=Cretaceous Research |volume=60 |pages=239–252 |doi=10.1016/j.cretres.2015.12.002 |issn=0195-6671}} Atractosteus survived the Cretaceous-Paleogene extinction event, with one articulated fossil of the species A. grandei being recovered from strata dated to just a few thousand years after the extinction event, making it the oldest known articulated vertebrate fossil from the Cenozoic.{{Cite journal |last1=Brownstein |first1=Chase Doran |last2=Lyson |first2=Tyler R. |date=2022 |title=Giant gar from directly above the Cretaceous–Palaeogene boundary suggests healthy freshwater ecosystems existed within thousands of years of the asteroid impact |journal=Biology Letters |language=en |volume=18 |issue=6 |doi=10.1098/rsbl.2022.0118 |issn=1744-957X |pmc=9198771 |pmid=35702983}} It was found throughout North America and Europe during the Paleogene, but by the Neogene this had shrunk to only certain parts of North America, where it is still found today.
Systematics
{{clade|style=font-size:100%;line-height:100%;width:600px;
|label1=Lepisosteidae
|1={{clade
|label1=Atractosteus
|1={{clade
|1=A. tropicus
|2={{clade
|2=A. spatula 100 px
}}
}}
|label2=Lepisosteus
|2={{clade
|1={{clade
|1=L. oculatus
}}
|2={{clade
}}
}}
}}
}}
=Species=
==Extant species==
| class="wikitable" | |||
| Image | Scientific name | Common name | Distribution |
|---|---|---|---|
| 120px | Atractosteus spatula Lacépède, 1803 | Alligator gar | Southern United States |
| 120px | Atractosteus tristoechus Bloch & J. G. Schneider, 1801 | Cuban gar | Western Cuba and the Isla de la Juventud |
| 120px | Atractosteus tropicus T. N. Gill, 1863 | Tropical gar | Southern Mexico to Costa Rica |
==Fossil species==
File:Atractosteus atrox 3.jpg, an Eocene-aged fossil species from the Green River Formation]]
File:Atractosteus strausi.jpg (=A. strausi)]]
The following fossil species are known:
- †Atractosteus atrox (Leidy, 1873)
- †Atractosteus grandei Brownstein & Lyson, 2022
- †Atractosteus messelensis Grande 2010
- †Atractosteus simplex (Leidy 1873)
Former fossil species:
- †Atractosteus cuneatus (Cope 1884) non (Cope 1878) (now in Cuneatus)
- †Atractosteus falipoui (Cavin & Brito 2001) (now in Oniichthys)
== Dubious fossil species ==
- †"Atractosteus" africanus (Arambourg & Joleaud, 1943){{cite journal |last1=Cavin |first1=Lionel |last2=Martin |first2=Michel |last3=Valentin |first3=Xavier |date=1996 |title=Occurrence of Atractosteus africanus (actinopterygii, lepisosteidae) in the early Campanien of Ventabren (Bouches-du-Rhône, France). Paleobiogeographical implications |journal=Revue de Paléobiologie |volume=15 |issue=1 |pages=1–7}} (nomen dubium, placement in Atractosteus disputed, often placed in the dubious genus Paralepisosteus)
- †"Atractosteus" emmonsi Hay 1929 (Miocene of North Carolina, nomen dubium)
- †"Atractosteus" lapidosus Hay 1919 (Pleistocene of Florida, nomen dubium)
- †Atractosteus occidentalis (Leidy 1856) non Wiley 1976 (Campanian of Montana, nomen dubium){{Cite journal |last=Grande |first=Lance |date=2010 |title=An Empirical Synthetic Pattern Study of Gars (lepisosteiformes) and Closely Related Species, Based Mostly on Skeletal Anatomy. the Resurrection of Holostei |url=https://www.jstor.org/stable/20787269 |journal=Copeia |volume=2010 |issue=2A |pages=iii–871 |jstor=20787269 |issn=0045-8511}}
The extinct nomen dubium fossil species A. strausi (Kinkelin, 1884) is based on a single Miocene-aged gar scale from Germany, and has often been used as the species for the Atractosteus gars from the older Messel Formation. Although this scale provides evidence for gars surviving in Europe as late as the Miocene, it is not diagnostic enough to be considered a member of Atractosteus, nor can the Messel gars (now placed in A. messelensis) be confidently placed in it.
References
{{Reflist}}
- {{FishBase genus | genus = Atractosteus| month = June| year = 2011}}
{{Ginglymodi|state=collapsed}}
{{Taxonbar|from=Q143251}}
Category:Taxa named by Constantine Samuel Rafinesque
Category:Extant Late Cretaceous first appearances
{{Lepisosteiformes-stub}}