Reconstruction of Rhamphodopsis threiplandi, by Stanton Fink.

Belongs within: Vertebrata.
Contains: Antiarchi, Arthrodira, Acanthodii, Actinopterygii, Sarcopterygii.

The Gnathostomata includes the jawed vertebrates, which first appeared in the Upper Silurian (Bond 1996).

Synapomorphies (from Bond 1996): Jaws present; gill tissue, branchial arteries and branchial nerves external to gill arches; pectoral and pelvic fins present; three semicircular canals present; branchial skeleton not fused to neurocranium; notochord partially or completely replaced by vertebrae.

<==Gnathostomata [Placodermi, Placodermomorphi]
    |  i. s.: Eleochera Sansom & Smith 2005 SS05
    |           `--*E. glossa Sansom & Smith 2005 SS05
    |         ‘Gyracanthus’ eastmani Wells 1944 TBW05
    |         Myducosteus anmaensis BST02
    |--Rhenanida [Rhenaniformes] SJ03
    `--+--Antiarchi SJ03
       `--+--Parayunnanolepis ZY13
          `--+--Acanthothoraci [Acanthothoraciformes, Palaeacanthaspidoidei] BLT98
             |    |--Romundina ZY13
             |    `--Brindabellaspis Young 1980 ZY13, BLT98
             |         `--*B. stensioi Young 1980 BLT98
             `--+--Petalichthyida [Petalichthyiformes] SJ03
                |    |  i. s.: Eurycaraspis ZY13
                |    |--Quasipetalichthys [Quasipetalichthyidae] JP97
                |    `--Macropetalichthyidae JP96
                |         |--Wijdeaspis arctica (Ørvig 1957) JP97
                |         |--Macropetalichthys rapheidolebis (Stensiö 1925) ZY13, JP97
                |         |--Xinanpetalichthys JP97
                |         |--Lunaspis broilii (Gross 1961) JP97
                |         |--Notopetalichthys hillsi Woodward 1941 JP97, F71
                |         |--Epipetalichthys JP97
                |         |--Sinopetalichthys kueiyangensis JP97
                |         |--Shearsbyaspis oepiki (Young 1985) JP97
                |         `--Guangxipetalichthys Ji & Pan 1997 JP97
                |              |--*G. bobaiensis Ji & Pan 1997 JP97
                |              `--G. tiaomajianensis Ji & Pan 1997 JP97
                `--+--Arthrodira ZY13
                   `--+--+--Osteichthyomorpha [Teleostomi] S85
                      |  |    |--Acanthodii ZY13
                      |  |    `--+--Lophosteus superbus ZZ09, BB07
                      |  |       `--+--Andreolepis hedei Gross 1968 ZZ09, BMM02
                      |  |          `--+--Dialipina salgueiroensis DFC12, ZZ09
                      |  |             `--+--Ligulalepis yunnanensis DFC12, ZZ09
                      |  |                `--Osteichthyes [Euteleostomi] ZY13
                      |  |                     |--Actinopterygii ZZ09
                      |  |                     `--Sarcopterygii ZZ09
                      |  `--Entelognathus Zhu, Yu et al. 2013 ZY13
                      |       `--*E. primordialis Zhu, Yu et al. 2013 ZY13
                      `--Ptyctodontida [Ptyctodontidae, Ptyctodontiformes] SJ03
                           |  i. s.: Ptyctodus Pander 1858 JE96
                           |           `--P. bradyi Hussakof 1942 JE96
                           |         Desmoporella minor JE96
                           |         Chelyophorus verneuili JE96
                           |         Tollodus JE96
                           |         Goniosteus JE96
                           |         Paleomylus JE96
                           |         Rhynchodus tetrodon (Jaekel 1903) (see below for synonymy) JE96
                           |         Ctenurella JE96
                           |           |--C. gardineri JE96
                           |           `--C. gladbachensis JE96
                           |         0--Ptyctodopsis menzeli JE96
                           |         `--Denisonodus Johnson & Elliott 1996 JE96
                           |              `--*D. plutonensis Johnson & Elliott 1996 JE96
                           |--Campbellodus decipiens ZY13, JE96
                           `--+--Austroptyctodus ZY13
                              `--Rhamphodopsis ZY13
                                   |--R. threiplandi JE96
                                   `--R. trispinatus JE96

Rhynchodus tetrodon (Jaekel 1903) [=Rhamphodus tetrodon, Rhamphodontus tetrodon; incl. Rhynchodontus eximius Jaekel 1919, Rhynchognathus wildungensis Jaekel 1929] JE96

*Type species of generic name indicated


[BMM02] Blom, H., T. Märss & C. G. Miller. 2002. Silurian and earliest Devonian birkeniid anaspids from the Northern Hemisphere. Transactions of the Royal Society of Edinburgh: Earth Sciences 92: 263-323.

Bond, C. E. 1996. Biology of Fishes, 2nd ed. Saunders College Publishing: Fort Worth.

[BB07] Botella, H., H. Blom, M. Dorka, P. E. Ahlberg & P. Janvier. 2007. Jaws and teeth of the earliest bony fishes. Nature 448: 583-586.

[BST02] Braddy, S. J., P. A. Selden & D. N. Truong. 2002. A new carcinosomatid eurypterid from the Upper Silurian of northern Vietnam. Palaeontology 45 (5): 897-915.

[BLT98] Burrow, C. J., J. A. Long & S. Turner. 1998. Lower Devonian microvertebrates from the Point Hibbs Formation, Tasmania. Alcheringa 22: 9-20.

[DFC12] Davis, S. P., J. A. Finarelli & M. I. Coates. 2012. Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes. Nature 486: 247-250.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

[JP97] Ji S. & Pan J. 1997. The macropetalichthyids (Placodermi) from Guangxi and Hunan, China. Vertebrata PalAsiatica 35 (1): 18-34.

[JE96] Johnson, H. G., & D. K. Elliott. 1996. A new ptyctodont (Placodermi) from the upper Devonian Martin Formation of northern Arizona, and an analysis of ptyctodont phylogeny. Journal of Paleontology 70 (6): 994-1003.

[SS05] Sansom, I. J., & M. P. Smith. 2005. Late Ordovician vertebrates from the Bighorn Mountains of Wyoming, USA. Palaeontology 48 (1): 31-48.

[SJ03] Smith, M. M., & Z. Johanson. 2003. Separate evolutionary origins of teeth from evidence in fossil jawed vertebrates. Science 299: 1235-1236.

[S85] Smithson, T. R. 1985. The morphology and relationships of the Carboniferous amphibian Eoherpeton watsoni Panchen. Zoological Journal of the Linnean Society 85: 317-410.

[TBW05] Turner, S., C. J. Burrow & A. Warren. 2005. Gyracanthides hawkinsi sp. nov. (Acanthodii, Gyracanthidae) from the Lower Carboniferous of Queensland, Australia, with a review of gyracanthid taxa. Palaeontology 48: 963-1006.

[ZY13] Zhu, M., X. Yu, P. E. Ahlberg, B. Choo, J. Lu, T. Qiao, Q. Qu, W. Zhao, L. Jia, H. Blom & Y. Zhu. 2013. A Sliurian placoderm with osteichthyan-like marginal jaw bones. Nature 502: 188-193.

[ZZ09] Zhu, M., W. Zhao, L. Jia, J. Lu, T. Qiao & Q. Qu. 2009. The oldest articulated osteichthyan reveals mosaic gnathostome characters. Nature 458: 469-474.


  1. Do you know if there's any good recent overview of the origin of gnathostomes available?

    Also, where's the chondrichthyans hiding in that dendrogram?

  2. I don't know what the best recent source for early gnathostome stuff is. The chondrichthyans are there, but they're indeed hiding. There's been a few recent studies that have nested the chondrichthyans inside the main bulk of the Acanthodii.

  3. Thanks. So chondrichthyans are osteichthyomorphs? Sounds like the later was given an unfortunate definition ...


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