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Brachydegma Temporal range: Leonardian 279.5–272.5 Ma^[1] PreꞒ Ꞓ O S D C P T J K Pg N

Interpretive drawing of the skull of the holotype of Brachydegma caelatum^[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	incertae sedis
Family:	incertae sedis
Genus:	†Brachydegma Dunkle, 1939
Species:	†B. caelatum
Binomial name
†Brachydegma caelatum Dunkle, 1939

Brachydegma is an extinct genus of prehistoric freshwater ray-finned fish that lived during the Leonardian age (Cisuralian/lower Permian) in what is now Texas, United States. It is known from two fossils, which were recovered from the Clear Fork Formation. A potential record is also known from the concurrent Hennessey Formation of Oklahoma.^[3] It is one of the only fossil ray-finned fish from the Permian that preserves the skull bones in three dimensions.^[2]

Classification

Brachydegma was first considered a "palaeoniscid".^[4] A later study rather suggested that Brachydegma could be one of the earliest crown neopterygians (Halecomorphi) known from the fossil record.^[5] However, this view relied on misinterpretations of cranial features. A more recent study yielded conflicting placements of Brachydegma on the actinopterygian tree of life, rendering its placement in an order or family difficult. It appears to be closely related or possibly a member of the crown group of Actinopterygii, though a closer relationship with either Neopterygii or Polypteriformes appears plausible.^[2]

References

^ "†Brachydegma Dunkle 1939 (ray-finned fish". Fossilworks.
^ ^a ^b ^c Argyriou, Thodoris; Giles, Sam; Friedman, Matt (2022). "A Permian fish reveals widespread distribution of neopterygian-like jaw suspension". eLife. 11: e584334. doi:10.7554/eLife.58433. PMC 9345605. PMID 35579418.
^ "PBDB". paleobiodb.org. Retrieved 2024-04-02.
^ Dunkle, David H. (1939). "A new palaeoniscid fish from the Texas Permian". American Journal of Science. 237 (4): 262–274. Bibcode:1939AmJS..237..262D. doi:10.2475/ajs.237.4.262.
^ Hurley, Imogen A.; Mueller, Rachael Lockridge; Dunn, Katherine A.; Schmidt, Eric J.; Friedman, Matt; Ho, Robert K.; Prince, Victoria E.; Yang, Ziheng; Thomas, Mark G.; Coates, Michael I. (2006). "A new time-scale for ray-finned fish evolution". Proceedings of the Royal Society B. 274 (1609): 489–498. doi:10.1098/rspb.2006.3749. PMC 1766393. PMID 17476768.

Actinopterygian genera

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Osteichthyes

Gnathostomata

see Gnathostomata
Actinopterygii	see below↓

Actinopterygii

†Austelliscus †Cheirolepis †Cuneognathus †Dialipina? †Kentuckia †Krasnoyarichthys †Ligulalepis? †Limnomis †Meemannia †Moythomasia †Naxilepis? †Orvikuina? †Osorioichthys †Palaeoneiros †Pickeringius †Raynerius †Stegotrachelus †Tegeolepis †Terenolepis?
†Howqualepididae	Donnrosenia Howqualepis
†Mimiidae	Gogosardina Mimipiscis
Post-Devonian taxa	see below↓

Post-Devonian taxa

†Adroichthys
†Aetheretmon
†Agecephalichthys
†Amblypterina
†Ambodipia
†Aneurolepis
†Angatubichthys
†Apateolepis
†Arratiaichthys
†Asarotus
†Australichthys
†Avonichthys
†Beagiascus
†Belichthys
†Bethesdaichthys
†Birgeria
†Bishofia
†Bluefieldius
†Blourugia
†Boreolepis
†Brachydegma
†Brachypareion
†Brazilichthys
†Burguklia
†Carbonilepis
†Caruichthys
†Centrolepis
†Charleuxia
†Chichia
†Coccocephalus
†Concentrilepis
†Cornuboniscus
†Cosmolepis
†Cosmoptychius
†Cretolepis
†Cylindrichthys
†Daqingshaniscus
†Disichthys
†Dmitrevichthys
†Drydenius
†Duwaichthys
†Dwykia
†Elpisopholis
†Ganolepis
†Gardinerichthys
†Gardinerpiscis
†Gondwanichthys
†Grandfieldia
†Guaymayenia
†Guntherichthys
†Gyrolepidoides
†Huanghelepis
†Hyllingea
†Illiniichthys
†Inichthys
†Irajapintoseidon
†Itararichthys
†Kalops
†Kansasiella
†Karaunguria
†Kazanichthys
†Kelliaichthys
†Kenderlichthys
†Khantausia
†Kompasia
†Kutaichthys
†Lambeia
†Lanarkichthys
†Lawrenciella
†Leptogenichthys
†Letovichthys
†Lineagruan
†Luederia
†Mansfieldiscus
†Megapteriscus
†Melanecta
†Mesembrioniscus
†Mesonichthys
†Mesopoma
†Ministrella
†Monesedeiphus
†Muensterichthys
†Myriolepis
†Nematoptychius
†Neuburgella
†Notacmon
†Novogonatodus
†Nozamichthys
†Oxypteriscus
†Pacorichthys
†Palaeobergia
†Paphosiscus
†Paradrydenius
†Paralogoniscus
†Peleichthys
†Piratata
†Phanerorhynchus
†Phanerosteon
†Praolepis
†Protamblyptera
†Pseudohaplolepis
†Psilichthys
†Pteroniscus
†Rastrolepis
†Reticulolepis
†Roslerichthys
†Rubidus
†Samarichthys
†Santosichthys
†Sceletophorus
†Schizolepis
†Senekichthys
†Sinkiangichthys
†Sinoniscus
†Sixtelia
†Sphaerolepis
†Spinofacia
†Strepheoschema
†Sundayichthys
†Tanypterichthys
†Tanyrhinichthys
†Tienshaniscus
†Trachelacanthus
†Trawdenia
†Turgoniscus
†Ufalepis
†Urosthenes
†Usclasichthys?
†Uydenia
†Uydenichthys
†Varialepis
†Wayaobulepis
†Westlepis
†Whiteichthys
†Willomorichthys
†Woodichthys
†Xingshikous
†Yogoniscus
†Yaomoshania
†Zhongweilepis

†Acrolepidae

Acrolepis
Acropholis
Challaia
Kasanilepis
Namaichthys
Plegmolepis
Progyrolepis?
Watsonichthys

†Aeduellidae

Aeduella
Bourbonnella
Decazella
Neslovicella
Platysella
Puertollanichthys
Schafeevus
Spinarichthys
Westollia

†Aesopichthyidae

Aesopichthys
Proceramala

†Amblypteridae

Amblypterus
Daphnaechelus
Korutichthys?
Lawnia
Paramblypterus
Tchekardichthys
Tholonosteon
Tholonotus

†Bobasatraniiformes

Dorypterus
Bobasatraniidae	Bobasatrania Ebenaqua Ecrinesomus?

†Canobiidae

Canobius
Schaefferius

†Discordichthyidae

Discordichthys
Geryonichthys
Mamulichthys
Mutovinia

†Eigiliidae

Eigilia
Strelnia

†Elonichthyidae

Alilepis
Elonichthys
Palaeostrugia?
Meisenheimichthys
Rhabdolepis?

†Eurynotiformes

Mesolepis Paramesolepis Proteurynotus Wardichthys
Amphicentridae	Amphicentrum Cheirodopsis Eurynotus
Styracopteridae	Benedenius Fouldenia Styracopterus