# Parexus

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Extinct genus of cartilaginous fishes

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Parexus Temporal range: Early Devonian Scientific classification Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Subclass: †Acanthodii Order: †Climatiiformes Family: †Climatiidae Genus: †Parexus Agassiz, 1845 Species: †P. recurvus Binomial name †Parexus recurvus Agassiz, 1845 Synonyms[1] Parexus falcatus Farnellia tuberculata Traquair

***Parexus*** is an extinct genus of [acanthodian fish](/source/Acanthodii). Acanthodians are often referred to as ‘spiny sharks’, although acanthodians are not true sharks and evolved perhaps 50 million years earlier than sharks. Acanthodians share several features with bony fish and cartilaginous fish; they often have spines supporting their fins.

*Parexus* is recognised by its large anterior dorsal fin spine. Several fossils have been discovered from the Early (Lower) Devonian Period of [Tillywhandland](https://en.wikipedia.org/w/index.php?title=Tillywhandland&action=edit&redlink=1), Scotland. Two species were described, *P. recurvus* and *P. falcatus*, both from Scotland; according to Burrow *et al.* (2013) *P. falcatus* is in fact a [junior synonym](/source/Synonym_(taxonomy)) of *P. recurvus*.[1]

## References

1. ^ [***a***](#cite_ref-Burrowetal_1-0) [***b***](#cite_ref-Burrowetal_1-1) Carole J. Burrow; Michael J. Newman; Robert G. Davidson; Jan L. den Blaauwen (2013). "Redescription of *Parexus recurvus*, an Early Devonian acanthodian from the Midland Valley of Scotland". *Alcheringa: An Australasian Journal of Palaeontology*. **37** (3): 392–414. [doi](/source/Doi_(identifier)):[10.1080/03115518.2013.765656](https://doi.org/10.1080%2F03115518.2013.765656). [S2CID](/source/S2CID_(identifier)) [84927480](https://api.semanticscholar.org/CorpusID:84927480).

v t e Genera of Chondrichthyes (including "acanthodians") Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Infraphylum: Gnathostomata Gnathostomata see Gnathostomata Chondrichthyes see below↓ Chondrichthyes †Altholepidiformes Altholepis Tezakia? †Elegestolepidida Kannathalepis Elegestolepididae Deltalepis Elegestolepis Ellesmereia †Tchunacanthidae Fecundosquama Lenacanthus Tchunacanthus †Ischnacanthiformes Acanthospina Campylodus Granulacanthus Onchus Serradentus Acritolepidae Acritolepis Monospina Nerepisacanthus Pechoralepis Ischnacanthidae Arcticacanthus Arenaceacanthus Atopacanthus Bracteatacanthus Cacheacanthus Erymnacanthus Euryacanthus Gomphonchus Grenfellacanthus Ischnacanthus Marsdenius? Persacanthus Plectrodus Rockycampacanthus Rohonilepis Taemasacanthus Tricuspicanthus Xylacanthus Podoliacanthidae Drygantacanthus Kasperacanthus Podoliacanthus Poracanthodidae Gomphonchoporus Machaeraporus Obruchevacanthus? Poracanthodes Radioporacanthodes Taimyrolepis Trundlelepis Zemlyacanthus †Diplacanthiformes Bryantonchus Culmacanthus? Devononchus Striacanthus Tetanopsyrus Uraniacanthus Diplacanthidae Angelacanthus Diplacanthus Florestacanthus Milesacanthus Ptychodictyon Rhadinacanthus †Acanthodiformes "Mesacanthidae" Lodeacanthus Melanoacanthus Mesacanthus Orcadacanthus Promesacanthus Teneracanthus? Triazeugacanthus "Cheiracanthidae" Cheiracanthus Fallodentus Ginkgolepis Homalacanthus Markacanthus Acanthodidae Acanthodes Acanthodopsis Traquairichthys Howittacanthidae Halimacanthodes Howittacanthus †"Climatiiformes" and related taxa Brochoadmones Dobunnacanthus Kathemacanthus Lupopsyroides Lupopsyrus Obtusacanthus "Climatiidae" Brachyacanthus Canadalepis Cheiracanthoides Climatius Eifellepis Endemolepis Erriwacanthus Hanilepis Iranolepis Laliacanthus Lijiangichthys Minioracanthus Nodocosta? Nostolepoides Parexus Ptomacanthus Sevyacanthus Tareyacanthus Vernicomacanthus Watsonacanthus Wetteldorfia Gyracanthidae Aganacanthus? Ankylacanthus Gyracanthides Gyracanthus Oracanthus? Vesperaliidae Acanthacanthus Vesperalia †Lamellin-forming taxa Fanjingshania Yuanolepis Sinacanthidae Eosinacanthus Hunanacanthus Neosinacanthus Sinacanthus Tarimacanthus Mongolepidida Solinalepis Mongolepididae Mongolepis Rongolepis Sodolepis Taklamakanolepis Teslepis Shiqianolepidae Chenolepis Shiqianolepis Tielikewatielepis Xiaohaizilepis Xinjiangichthys †Incertae sedis Cassidiceps Euthacanthus Janusiscus? Latviacanthus Machaeracanthus Paucicanthus Qianodus Ramirosuarezia? Shenacanthus "Conventionally defined chondrichthyans" see below↓ "Conventionally defined chondrichthyans" †Pucapampellidae Gydoselache Pucapampella †Omalodontiformes Siberiodus Aztecodontidae Aztecodus Manberodus Omalodontidae Doliodus? Omalodus Portalodus †Antarctilamnidae Antarctilamna Wellerodus †Mcmurdodontidae Maiseyodus Mcmurdodus †Symmoriiformes Dwykaselachus Ferromirum Kawichthys Kungurodus? Maiseyacanthus Cladoselachidae Cladoselache Maghriboselache Falcatidae Cosmoselachus Damocles Denaea Falcatus Ozarcus? Stethacanthulus Symmoriidae Akmonistion Cobelodus Crioselache? Gutturensis Stethacanthus Symmorium Holocephali see Holocephali includes chimaeras †"Ctenacanthiformes" Neosaivodus Saivodus Sculptospina Tamiobatis Ctenacanthidae Arduodens? Cladodoides Cladodus Ctenacanthus Goodrichthys Natarapax? Troglocladodus Heslerodidae Avonacanthus Bythiacanthus Dracopristis Glencartius Glikmanius Heslerodoides Heslerodus Kaibabvenator Nanoskalme †Jalodontidae Adamantina Isacrodus Jalodus Keuperodus Texasodus †Phoebodontidae Diademodus? Phoebodus Thrinacodus †Bransonelliformes Barbclabornia Bransonella †Xenacanthiformes Orthacanthus Tikiodontus Diplodoselachidae Decentrodus Diplodoselache Hagenoselache Hokomata Lebachacanthus Reginaselache Taquaralodus Xenacanthidae Mooreodontus Plicatodus Triodus Wurdigneria Xenacanthus †Incertae sedis Amelacanthus Carcharopsis Celtiberina Delphyodontos Diablodontus Eunemacanthus Gladbachus? Gogoselachus Karksiodus Leonodus Parhybodus Plesioselachus Polymerolepis Protodus Rosaodus Samarodus Squatinactis Xenosynechodus Euselachii see below↓ Euselachii †"Protacrodontidae" Dalmehodus Deihim Gzhelodus Microklomax Novaculodus Protacrodus †Homalodontidae Homalodontus Prolatodon †Sphenacanthidae Desinia Khuffia Rubencanthus? Sphenacanthus Wodnika †Tristychiidae Acronemus? Tristychius †Hybodontiformes Acrodus Asteracanthus Bdellodus Carinacanthus Columnaodus Dabasacanthus? Gansuselache Hamiltonichthys Heteroptychodus Hubeiodus Isanodus Khoratodus Lissodus Mukdahanodus Onychoselache? Palaeobates Polyacrodus Reesodus Steinbachodus Strophodus Thaiodus Distobatidae Aegyptobatus Distobates Reticulodus Tribodus? Hybodontidae Crassodus Durnonovariaodus? Egertonodus Hybodus Meristodonoides Planohybodus Priohybodus Secarodus? Lonchidiidae Bahariyodon Diplolonchidion Hylaeobatis Jiaodontus Lonchidion Lonchidionoides Luopingselache Parvodus Pristrisodus Vectiselachos †Incertae sedis Artiodus Bandringa Cassisodus Doratodus Favusodus Gissarodus Hopleacanthus Lamarodus Mesodmodus Omanoselache Ossianodus Pororhiza Pseudodalatias Roongodus Teresodus Tiaraju Elasmobranchii sensu stricto (Neoselachii) †Anachronistidae? Amaradontus Cooleyella Ginteria Gunnellia Reifella Turovella †"Synechodontiformes" Antrigoulia Keichouodus Mucrovenator Nemacanthus Palaeospinax Palidiplospinax Parascylloides Polyfaciodus Rhomaleodus Rhomphaiodon Safrodus Synechodus Wimanodon †Incertae sedis Cretacladoides? Duffinselache Eorapax Grozonodon Nanocetorhinus Odontorhytis Vallisodus Crown-Elasmobranchii Batomorphi Selachii Galeomorphi Squalomorphi Incertae sedis scale-based taxa Altacollum Arauzia Canyonlepis? Cladolepis Frigorilepis? Funicristata Gualepis Hercynolepis Iberolepis Ivanelepis Jolepis Karksilepis Knerialepis Lugalepis Lunalepis Modicucollum Nobilesquama Nogueralepis Nostolepis Nostovicina Ohiolepis Seretolepis Serpensiugum Tuvalepis Verrucasquama Wellingtonella? Category Commons

Taxon identifiers Parexus Wikidata: Q7136939 Wikispecies: Parexus GBIF: 4823738 IRMNG: 1392516 Open Tree of Life: 4140900 Paleobiology Database: 256940 Parexus recurvus Wikidata: Q20719008 GBIF: 8668465 Open Tree of Life: 6159957 Paleobiology Database: 256941

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