View source for Tribodus

{{short description|Genus of hybodont shark from the Early Cretaceous period}}
{{Automatic taxobox
| fossil_range = {{fossilrange|Albian|Cenomanian}}
| taxon = Tribodus
| authority = Brito & Ferreira, 1989
| type_species = {{extinct}}'''''Tribodus limae'''''
| type_species_authority = Brito & Ferreira, 1989
| subdivision_ranks = Other species
| subdivision = *''Tribodus morlati'' Landemaine, 1991
}}
'''''Tribodus''''' is an extinct genus of [[hybodont]]. It lived during the mid Cretaceous ([[Albian]]-[[Cenomanian]]) with fossils being known from northern South America, North Africa, and southern Europe.<ref name=":0">R. Vullo, D. Néraudeau [https://geojournals.pgi.gov.pl/agp/article/view/10011 When the “primitive” shark ''Tribodus'' (Hybodontiformes) meets the “modern” ray ''Pseudohypolophus'' (Rajiformes), the unique co-occurrence of these two durophagous Cretaceous selachians in Charentes (SW France)] Acta Geologica Polonica, 58 (2) (2008), pp. 249-255</ref>
== Description ==
This genus is known from articulated and somewhat complete specimens of ''Tribodus limae'' from the [[Romualdo Formation]] and [[Alcântara Formation]] of northeastern Brazil, making it one of the few hybodonts to be known from full body remains.<ref name="Triboduslimae">{{cite journal|last1=Maisey|first1=J.G.|last2=Denton|first2=J.S.S.|year=2016|title=Dermal denticle patterning in the Cretaceous hybodont shark ''Tribodus limae'' (Euselachii, Hybodontiformes), and its implications for the evolution of patterning in the chondrichthyan dermal skeleton|journal=Journal of Vertebrate Paleontology|pages=e1179200-2|volume=36|issue=5|doi=10.1080/02724634.2016.1179200|bibcode=2016JVPal..36E9200M |doi-access=free}}</ref><ref name="Tribodus">{{Cite journal|last1=Lane|first1=Jennifer A.|last2=Maisey|first2=John G.|date=2012|title=The Visceral Skeleton and Jaw Suspension In the Durophagous Hybodontid Shark ''Tribodus limae'' from the Lower Cretaceous of Brazil|url=https://bioone.org/journals/Journal-of-Paleontology/volume-86/issue-5/11-139.1/The-Visceral-Skeleton-and-Jaw-Suspension-In-the-Durophagous-Hybodontid/10.1666/11-139.1.full|journal=Journal of Paleontology|volume=86|issue=5|pages=886–905|doi=10.1666/11-139.1|bibcode=2012JPal...86..886L |s2cid=86285896|issn=0022-3360}}</ref> Like other hybodonts, ''Tribodus'' had dorsal fin-spines and cephalic spines in male individuals.<ref name="Tribodus" /> The skin of ''Tribodus'' had two distinct types of [[dermal denticles]].<ref>{{Cite journal |last1=Maisey |first1=John G. |last2=Denton |first2=John S. S. |date=2016-09-02 |title=Dermal denticle patterning in the Cretaceous hybodont shark Tribodus limae (Euselachii, Hybodontiformes), and its implications for the evolution of patterning in the chondrichthyan dermal skeleton |journal=Journal of Vertebrate Paleontology |language=en |volume=36 |issue=5 |pages=e1179200 |doi=10.1080/02724634.2016.1179200 |bibcode=2016JVPal..36E9200M |s2cid=88591830 |issn=0272-4634|doi-access=free }}</ref> ''Tribodus limae'' reached a total length of about {{Convert|1|m|ft}}.<ref name=":1">{{Cite journal |last1=Vullo |first1=Romain |last2=Néraudeau |first2=Didier |last3=Dépré |first3=Eric |date=October 2013 |title=Vertebrate remains from the Cenomanian (Late Cretaceous) plant-bearing Lagerstätte of Puy-Puy (Charente-Maritime, France) |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667113001043 |journal=Cretaceous Research |language=en |volume=45 |pages=314–320 |bibcode=2013CrRes..45..314V |doi=10.1016/j.cretres.2013.06.002}}</ref> The lower jaw was relatively short and did not extend to the snout region and articulated with the upper jaw at exclusively at the [[hyoid arch]] unlike other hybodonts, with a number of cartilage struts connecting the upper and lower jaws which enhanced jaw strength.<ref name="Tribodus" /> The teeth of ''Tribodus'' were specialised for [[durophagy]] (consuming hard shelled organisms). They were small, less than {{Convert|5|mm|in|frac=32}} across and polygonal with a low cusp, and collectively formed a flat pavement that was effective at grinding, similar to those of living [[Stingray|myliobatoid]] rays.<ref name=":0" /><ref>{{Cite journal |last1=Benyoucef |first1=Madani |last2=Pérez-García |first2=Adán |last3=Bendella |first3=Mohamed |last4=Ortega |first4=Francisco |last5=Vullo |first5=Romain |last6=Bouchemla |first6=Imad |last7=Ferré |first7=Bruno |date=2022-07-06 |title=The "mid"-Cretaceous (Lower Cenomanian) Continental Vertebrates of Gara Samani, Algeria. Sedimentological Framework and Palaeodiversity |journal=Frontiers in Earth Science |volume=10 |doi=10.3389/feart.2022.927059 |bibcode=2022FrEaS..10.7059B |issn=2296-6463 |doi-access=free }}</ref><ref name="Tribodus" /> It is suggested to have been a [[Benthic zone|benthic]] feeder, with shrimp being discovered as stomach contents in some specimens.<ref name="Tribodus" />
Species of ''Tribodus'' have been found in shallow marine as well as [[Fluvial sediment processes|fluvial]] and [[deltaic]] environments. It may have spawned in shallow-water vegetated areas.<ref name=":1" />
== Classification ==
Its placement within the Hybodontiformes is uncertain. Historically it has been asserted to be a member of the family Acrodontidae with other durophagous hybodonts, based on the presence of columnar osteodentine in its teeth.<ref name="Tribodus" /> However, other authors have suggested that it should instead be placed in the family Distobatidae due the morphology of its teeth closely resembling members of that family.<ref name=":2">{{Cite journal |last1=Stumpf |first1=Sebastian |last2=López-Romero |first2=Faviel A. |last3=Kindlimann |first3=René |last4=Lacombat |first4=Frederic |last5=Pohl |first5=Burkhard |last6=Kriwet |first6=Jürgen |date=August 2021 |editor-last=Cavin |editor-first=Lionel |title=A unique hybodontiform skeleton provides novel insights into Mesozoic chondrichthyan life |journal=Papers in Palaeontology |language=en |volume=7 |issue=3 |pages=1479–1505 |doi=10.1002/spp2.1350 |issn=2056-2799 |doi-access=free|bibcode=2021PPal....7.1479S }}</ref>
== References ==
{{reflist}}
{{Taxonbar|from=Q95449812}}
[[Category:Hybodontiformes]]
[[Category:Cretaceous cartilaginous fish]]
[[Category:Prehistoric fish of South America]]
[[Category:Early Cretaceous animals of South America]]
[[Category:Albian life]]
[[Category:Aptian life]]
[[Category:Cenomanian life]]
[[Category:Cretaceous Brazil]]
[[Category:Fossils of Brazil]]
[[Category:Romualdo Formation]]
[[Category:Fish described in 1989]]
[[Category:Taxa named by Alberto Brito]]
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