# Falcatus

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Extinct genus of cartilaginous fishes

Falcatus Temporal range: 335–318 Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Viséan - Late Serpukhovian Specimen in Vienna Scientific classification Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Order: †Symmoriiformes Family: †Falcatidae Genus: †Falcatus Lund, 1985 Species Falcatus falcatus

***Falcatus*** is an extinct genus of [falcatid](/source/Falcatidae) [chondrichthyan](/source/Chondrichthyan) which lived during the early [Carboniferous Period](/source/Carboniferous_Period) in [Bear Gulch bay](/source/Bear_Gulch_Limestone) in what is now [Montana](/source/Montana).

## Description

Life restoration of female (top) and male (bottom)

*Falcatus falcatus* male. Lower Carboniferous, Montana, USA

This fish was quite small, only getting to around 25–30 cm or 10-12 inches long. This is about as big as some of the smallest sharks around today, like the [pygmy lanternshark](/source/Pygmy_lanternshark).[1] *Falcatus* was a chondrichthyan known as a "[cladodont](/source/Cladodont)-toothed stethacanthid [holocephalan](/source/Holocephali)".[2] The first material known from the genus were the prominent fin spines that curve anteriorly over the head of the animal. When first described in 1883 from the [St. Louis Limestone](/source/St._Louis_Limestone), these remains were given the name *Physonemus falcatus*. However, in 1985, fossils of a new type of chondrichthyan from [Montana](/source/Montana) were described that displayed a high degree of [sexual dimorphism](/source/Sexual_dimorphism). The same spines that were previously named *P. falcatus* were found on one of the morphs, identified as the male due to the presence of [valvae](/source/Valva).[3]

## Classification

Despite often being called a shark, *Falcatus* and its relatives were part of the order [Symmoriiformes](/source/Symmoriiformes), which itself was part of the [subclass](/source/Subclass_(biology)) Holocephali.[3] This means that this fish was more closely related to [Chimaeras](/source/Chimaera) than to true sharks.[4] Other members of its family include *[Ozarcus](/source/Ozarcus)* from the Carboniferous of [Arkansas](/source/Arkansas),[5] and potentially *[Cretacladoides](/source/Cretacladoides)* from the [Cretaceous](/source/Cretaceous) of Austria.[6]

Two *[Stethacanthus](/source/Stethacanthus)* species, *S. altonensis* and *S. productus*, lived alongside *Falcatus*

## Paleoecology

Main article: [Bear Gulch Limestone](/source/Bear_Gulch_Limestone)

The bear gulch limestone is a fossil deposit from the [Big Snowy Mountains](/source/Big_Snowy_Mountains) of Montana. It is a smaller part of the larger St. louis limestone, which dates to the middle carboniferous. During the time, the area was a series of [mudflats](/source/Mudflat) and [lagoons](/source/Lagoon) with brackish and freshwater.[7] Many theories have been put forth for the preservation. One is that the creatures sank to the bottom and died of [asphyxiation](/source/Asphyxia) in the [oxygen](/source/Oxygen) poor waters, being preserved without scavenging took place.[8] Another theory is that the bottom of the bay created mudslides because of heavy rainfall, which rapidly buried the creatures.[9] However, because many of the fish fossils were found with distended gills, this would suggest death by asphyxiation.[10] Falcatus lived alongside many strange creatures like the chondrichthyans *[Agassizodus](/source/Agassizodus),* *[Listracanthus](/source/Listracanthus)[11]* and *[Delphyodontos](/source/Delphyodontos).*[12] It also lived alongside many [ray-finned fish](/source/Actinopterygii) like *[Discoserra](/source/Discoserra)[13]* and [*Paratarrasius*](/source/Tarrasiiformes).*[14]* Other fish included the [rhabdodermatid](/source/Rhabdodermatidae) [*Cardiosuctor*](/source/Caridosuctor),*[15]* the [rhizodont](/source/Rhizodontida) *[Strepsodus](/source/Strepsodus),[16]* and *[Hardistiella](/source/Hardistiella)*, one of the oldest known [lamprey](/source/Lamprey).[17] The [invertebrates](/source/Invertebrate) of bear gulch were very diverse creatures, like the [hoplocarids](/source/Hoplocarida) (relatives of the [mantis shrimp](/source/Mantis_shrimp)),[18] *[Anderella](/source/Anderella)*, which is the youngest known [synziphosurine](/source/Synziphosurina)*[19]* and more enigmatic creatures like the potential gastropod relative *[Typhloesus](/source/Typhloesus),[20]* and the "Square objects" which might be [sea salps](/source/Salp) or [cnidarians](/source/Cnidaria).[21] Other inverts include, mollusks like the [nautiloid](/source/Nautiloid) *[Tylonautilus](/source/Tylonautilus),[22]* [pterioid](/source/Pteriida) [bivalves](/source/Bivalvia) which have been found encrusting *[sargassum](/source/Sargassum)* like brown algae*[23]* as well as [productid](/source/Productida) [brachiopods](/source/Brachiopod),[24] [*Paleolimulus*](/source/List_of_xiphosuran_genera),*[25]* [phyllocarids](/source/Phyllocarida)[26] and [echinoderms](/source/Echinoderm) like [Crinoids](/source/Crinoid), [echinoids](/source/Sea_urchin), [sea stars](/source/Starfish), [brittle stars](/source/Brittle_star) and a many armed starfish called *Lepidasterella montanensis.[27]*

## References

- David Norman. (2001): The Big Book Of Dinosaurs. Pg.84 and Pg.286, Walcome books.

1. **[^](#cite_ref-1)** ["A Golden Age of Sharks"](http://www.elasmo-research.org/education/evolution/golden_age.htm). *elasmo-research.org*.

1. **[^](#cite_ref-2)** ["Bear Gulch - Falcatus falcatus"](https://web.archive.org/web/20080821203413/http://www.sju.edu/research/bear_gulch/pages_fish_species/Falcatus_falcatus.php). Archived from [the original](http://www.sju.edu/research/bear_gulch/pages_fish_species/Falcatus_falcatus.php) on 2008-08-21. Retrieved 2008-09-04. Fossil Fish of Bear Gulch 2005 by Richard Lund and Eileen Grogan Accessed 2009-01-14

1. ^ [***a***](#cite_ref-:0_3-0) [***b***](#cite_ref-:0_3-1) The morphology of *Falcatus falcatus* (St. John and Worthen), a Mississippian stethacanthid chondrichthyan from the Bear Gulch Limestone of Montana. *Journal of Vertebrate Paleontology* **5**(1):1-19.

1. **[^](#cite_ref-:1_4-0)** Coates, M., Gess, R., Finarelli, J., Criswell, K., Tietjen, K. 2016. A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes. Nature. doi: 10.1038/nature20806

1. **[^](#cite_ref-ozarcus_5-0)** Alan Pradel; John G. Maisey; Paul Tafforeau; Royal H. Mapes; Jon Mallatt (2014). "A Palaeozoic shark with osteichthyan-like branchial arches". *Nature*. **509** (7502): 608–611. [doi](/source/Doi_(identifier)):[10.1038/nature13195](https://doi.org/10.1038%2Fnature13195). [PMID](/source/PMID_(identifier)) [24739974](https://pubmed.ncbi.nlm.nih.gov/24739974). [S2CID](/source/S2CID_(identifier)) [3504437](https://api.semanticscholar.org/CorpusID:3504437).

1. **[^](#cite_ref-6)** Iris Feichtinger; Andrea Engelbrecht; Alexander Lukeneder; Jürgen Kriwet (2018). "New chondrichthyans characterised by cladodont-like tooth morphologies from the Early Cretaceous of Austria, with remarks on the microstructural diversity of enameloid". *Historical Biology: An International Journal of Paleobiology*. **32** (6): 1–14. [doi](/source/Doi_(identifier)):[10.1080/08912963.2018.1539971](https://doi.org/10.1080%2F08912963.2018.1539971). [S2CID](/source/S2CID_(identifier)) [92392461](https://api.semanticscholar.org/CorpusID:92392461).

1. **[^](#cite_ref-7)** ["Bear Gulch Limestone Fossil Lagerstätte"](http://www.fossilmuseum.net/Fossil_Sites/beargulch.htm). *fossilmuseum.net*.

1. **[^](#cite_ref-:9_8-0)** Grogan, Eileen D.; Lund, Richard (1997). ["Soft tissue pigments of the Upper Mississippian chondrenchelyid, *Harpagofututor volsellorhinus* (Chondrichthyes, Holocephali) from the Bear Gulch Limestone, Montana, USA"](https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/soft-tissue-pigments-of-the-upper-mississippian-chondrenchelyid-harpagofututor-volsellorhinus-chondrichthyes-holocephali-from-the-bear-gulch-limestone-montana-usa/E8F6AEF8F06E7F34DC79657BA4C0A311). *Journal of Paleontology*. **71** (2): 337–342. [doi](/source/Doi_(identifier)):[10.1017/S002233600003924X](https://doi.org/10.1017%2FS002233600003924X). [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360).

1. **[^](#cite_ref-:12_9-0)** Grogan, Eileen D.; Lund, Richard (2002). ["The geological and biological environment of the Bear Gulch Limestone (Mississippian of Montana, USA) and a model for its deposition"](https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2002n2a2.pdf) (PDF). *Geodiversitas*. **24** (2): 295–315.

1. **[^](#cite_ref-:02_10-0)** Hagadorn, James W. (2002). ["Bear Gulch: An Exceptional Upper Carboniferous Plattenkalk"](https://www.researchgate.net/publication/242175100). In Bottjer, D.J.; Etter, W.; Hagadorn, J.W.; Tang, C.M. (eds.). *Exceptional fossil preservation; a unique view on the evolution of marine life*. New York: Columbia University Press. pp. 167–183.

1. **[^](#cite_ref-:23_11-0)** Lund, Richard (1990-01-01). "Chondrichthyan life history styles as revealed by the 320 million years old Mississippian of Montana". *Environmental Biology of Fishes*. **27** (1): 1–19. [doi](/source/Doi_(identifier)):[10.1007/BF00004900](https://doi.org/10.1007%2FBF00004900). [ISSN](/source/ISSN_(identifier)) [1573-5133](https://search.worldcat.org/issn/1573-5133). [S2CID](/source/S2CID_(identifier)) [13249799](https://api.semanticscholar.org/CorpusID:13249799).

1. **[^](#cite_ref-12)** Lund, Richard (1980-08-08). ["Viviparity and Intrauterine Feeding in a New Holocephalan Fish from the Lower Carboniferous of Montana"](https://www.researchgate.net/publication/6019589). *Science*. **209** (4457): 697–699. [Bibcode](/source/Bibcode_(identifier)):[1980Sci...209..697L](https://ui.adsabs.harvard.edu/abs/1980Sci...209..697L). [doi](/source/Doi_(identifier)):[10.1126/science.209.4457.697](https://doi.org/10.1126%2Fscience.209.4457.697). [PMID](/source/PMID_(identifier)) [17821193](https://pubmed.ncbi.nlm.nih.gov/17821193). [S2CID](/source/S2CID_(identifier)) [36858963](https://api.semanticscholar.org/CorpusID:36858963).

1. **[^](#cite_ref-:19_13-0)** Lund, Richard (2000). ["The new Actinopterygian order Guildayichthyiformes from the Lower Carboniferous of Montana (USA)"](https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/g2000n2a2.pdf) (PDF). *Geodiversitas*. **22** (2): 171–206.

1. **[^](#cite_ref-14)** Lund, Richard; Melton, William G. Jr. (1982). ["A new actinopterygian fish from the Mississippian Bear Gulch Limestone of Montana"](https://www.palass.org/publications/palaeontology-journal/archive/25/3/article_pp485-498). *Palaeontology*. **25** (3): 485–498.

1. **[^](#cite_ref-:14_15-0)** Lund, Richard; Lund, Wendy (1984). "New genera and species of coelacanths from the Bear Gulch Limestone (Lower Carboniferous) of Montana (U.S.A.)". *Geobios*. **17** (2): 237–244. [doi](/source/Doi_(identifier)):[10.1016/s0016-6995(84)80145-x](https://doi.org/10.1016%2Fs0016-6995%2884%2980145-x). [ISSN](/source/ISSN_(identifier)) [0016-6995](https://search.worldcat.org/issn/0016-6995).

1. **[^](#cite_ref-:6_16-0)** Lund, Richard; Greenfest-Allen, Emily; Grogan, Eileen D. (2015-02-01). "Ecomorphology of the Mississippian fishes of the Bear Gulch Limestone (Heath formation, Montana, USA)". *Environmental Biology of Fishes*. **98** (2): 739–754. [doi](/source/Doi_(identifier)):[10.1007/s10641-014-0308-x](https://doi.org/10.1007%2Fs10641-014-0308-x). [ISSN](/source/ISSN_(identifier)) [1573-5133](https://search.worldcat.org/issn/1573-5133). [S2CID](/source/S2CID_(identifier)) [14850973](https://api.semanticscholar.org/CorpusID:14850973).

1. **[^](#cite_ref-:34_17-0)** Janvier, Philippe; Lund, Richard (1983). "*Hardistiella montanensis* n. gen. et sp. (Petromyzontida) from the Lower Carboniferous of Montana, with remarks on the affinities of the lampreys". *Journal of Vertebrate Paleontology*. **2** (4): 407–413. [doi](/source/Doi_(identifier)):[10.1080/02724634.1983.10011943](https://doi.org/10.1080%2F02724634.1983.10011943). [ISSN](/source/ISSN_(identifier)) [0272-4634](https://search.worldcat.org/issn/0272-4634).

1. **[^](#cite_ref-FF85_18-0)** Factor, David F.; Feldmann, Rodney M. (11 October 1985). ["Systematics and paleoecology of malacostracan arthropods in the Bear Gulch Limestone (Namurian) of Central Montana"](https://www.biodiversitylibrary.org/page/52403449#page/343/mode/1up). *Annals of Carnegie Museum*. **54** (10): 319–356.

1. **[^](#cite_ref-:33_19-0)** Moore, Rachel A.; McKenzie, Scott C.; Lieberman, Bruce S. (2007). ["A Carboniferous synziphosurine (Xiphosura) from the Bear Gulch Limestone, Montana, USA"](https://mndi.museunacional.ufrj.br/aracnologia/Xiphosura/Moore%20et%20al%202007.pdf) (PDF). *Palaeontology*. **50** (4): 1013–1019. [doi](/source/Doi_(identifier)):[10.1111/j.1475-4983.2007.00685.x](https://doi.org/10.1111%2Fj.1475-4983.2007.00685.x). [ISSN](/source/ISSN_(identifier)) [1475-4983](https://search.worldcat.org/issn/1475-4983).

1. **[^](#cite_ref-:13_20-0)** Conway Morris, Simon (1990-04-12). ["*Typhloesus wellsi* (Melton and Scott, 1973), a bizarre metazoan from the Carboniferous of Montana, U. S. A"](https://royalsocietypublishing.org/doi/abs/10.1098/rstb.1990.0102). *Philosophical Transactions of the Royal Society of London. B, Biological Sciences*. **327** (1242): 595–624. [Bibcode](/source/Bibcode_(identifier)):[1990RSPTB.327..595M](https://ui.adsabs.harvard.edu/abs/1990RSPTB.327..595M). [doi](/source/Doi_(identifier)):[10.1098/rstb.1990.0102](https://doi.org/10.1098%2Frstb.1990.0102).

1. **[^](#cite_ref-21)** ["Description of the 'square objects' of the Bear Gulch Limestone, Montana, USA"](https://www.newhaven.edu/_resources/documents/academics/surf/past-projects/2015/stephanie-rosbach-paper.pdf) (PDF). *newhaven.edu*.

1. **[^](#cite_ref-:7_22-0)** Cox, Robt S. (1986). ["Preliminary report on the age and palynology of the Bear Gulch Limestone (Mississippian, Montana)"](https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/preliminary-report-on-the-age-and-palynology-of-the-bear-gulch-limestone-mississippian-montana/555EDC346DDB615D3CA2741592F93383). *Journal of Paleontology*. **60** (4): 952–956. [doi](/source/Doi_(identifier)):[10.1017/S0022336000043092](https://doi.org/10.1017%2FS0022336000043092). [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360).

1. **[^](#cite_ref-:31_23-0)** McRoberts, Christopher A.; Stanley, George D. (1989). ["A unique bivalve–algae life assemblage from the Bear Gulch Limestone (Upper Mississippian) of central Montana"](https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/unique-bivalvealgae-life-assemblage-from-the-bear-gulch-limestone-upper-mississippian-of-central-montana/A3CCEA3C99F10D7E5954426E3332074C). *Journal of Paleontology*. **63** (5): 578–581. [doi](/source/Doi_(identifier)):[10.1017/S0022336000041214](https://doi.org/10.1017%2FS0022336000041214). [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360).

1. **[^](#cite_ref-SH785_24-0)** Schram, Frederick R.; Horner, John (1978). "Crustacea of the Mississippian Bear Gulch Limestone of Central Montana". *Journal of Paleontology*. **52** (2): 394–406. [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360). [JSTOR](/source/JSTOR_(identifier)) [1303712](https://www.jstor.org/stable/1303712).

1. **[^](#cite_ref-S79Limulines_25-0)** Schrams, Frederick R. (1979). ["Limulines of the Mississippian Bear Gulch Limestone of Central Montana, USA"](https://www.biodiversitylibrary.org/page/5784863#page/81/mode/1up). *Transactions of the San Diego Society of Natural History*. **19** (6): 67–74.

1. **[^](#cite_ref-SH78_26-0)** Schram, Frederick R.; Horner, John (1978). "Crustacea of the Mississippian Bear Gulch Limestone of Central Montana". *Journal of Paleontology*. **52** (2): 394–406. [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360). [JSTOR](/source/JSTOR_(identifier)) [1303712](https://www.jstor.org/stable/1303712).

1. **[^](#cite_ref-27)** Welch, James R. (1984). "The Asteroid, *Lepidasterella montanensis* n. sp., from the Upper Mississippian Bear Gulch Limestone of Montana". *Journal of Paleontology*. **58** (3): 843–851. [ISSN](/source/ISSN_(identifier)) [0022-3360](https://search.worldcat.org/issn/0022-3360). [JSTOR](/source/JSTOR_(identifier)) [1304921](https://www.jstor.org/stable/1304921).

## External links

- [http://www.elasmo-research.org/education/evolution/golden_age.htm](http://www.elasmo-research.org/education/evolution/golden_age.htm)

- [https://web.archive.org/web/20070927011823/http://comenius.susqu.edu/biol/202/Animals/DEUTEROSTOMES/CRANIATA/CHONDRICHTHYES.htm](https://web.archive.org/web/20070927011823/http://comenius.susqu.edu/biol/202/Animals/DEUTEROSTOMES/CRANIATA/CHONDRICHTHYES.htm)

- [Paleontology portal](https://en.wikipedia.org/wiki/Portal:Paleontology)

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 Falcatus Wikidata: Q144625 EoL: 10524414 GBIF: 4824086 IRMNG: 1426847 Open Tree of Life: 4143131 Paleobiology Database: 34440

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Adapted from the Wikipedia article [Falcatus](https://en.wikipedia.org/wiki/Falcatus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Falcatus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.