Field of Science

Koskinonodon it is!

Mueller (2007) noted that the name Buettneria Case 1922, for the large Late Triassic metoposaurid from the United States, was preoccupied, and recommended the next available name Koskinonodon Branson and Mehl 1929 as the replacement name for this taxon. 

Subsequently Lucas et al. (2007) petitioned the International Committee of Zoological Nomenclature (ICZN) to conserve this name.  Details of the case and  comments are available here (click expand on Case 3420).  The final opinion can be found here.

Main Reference:

Mueller, B. D. 2006. Koskinonodon Branson and Mehl, 1929, a replacement name for the preoccupied temnospondyl Buettneria Case, 1922. Journal of Vertebrate Paleontology 27:225.


  1. Seems like the right decision. As one of the comments said, supressing the snail's genus would give bad precedent for ignoring priority when poorly known taxa are involved.

  2. The last one, P. Bouchet's comment, is the best.

  3. With very few exceptions most Triassic workers have switched to Koskinonodon since 2007 anyhow. The names for the specimens have changed so much over the decades (e.g., Buettneria -> Eupelor -> Metoposaurus -> Buettneria -> Koskinonodon)it's not really a problem.

  4. Now we just need to settle on always using the correct spelling of the species name, K. perfectus (I still see the incorrect gender agreements of K. perfecta and K. perfectum from time to time.)

    Permo-Triassic workers can claim one victory for nomenclatural stability from this issue of the BZN, though: my proposal to conserve the generic name Procynosuchus for a very well-known basal cynodont (threatened by the rarely-mentioned senior synonyms Cyrbasiodon and Parathrinaxodon) was approved by the Commission. Let there be celebration across the land.


  5. Congrats!

    Does the recent version of the ICZN require gender agreement between the genus and species. I recollect that maybe they had done away with that requirement on taxa where the genus name changes to maintain stability of the spelling of the species name.

  6. There is a lot more leeway with regards to proper species construction in the current (4th) edition of the Code than in previous versions (e.g., gender changes for misconstructed honorifics are no longer required, despite the barbarous nature of using an -i for an -orum or an -ae for an -i), but Art. 31.2 is still very much in effect. "Art. 31.2 Agreement in gender. A species-group name, if it is or ends in a Latin or latinized adjective or participle in the nominative singular, must agree in gender with the generic name with which it is at any time combined." Because perfectus and Koskinonodon are very much latinized names, the terminal part of the species name must agree with the genus.
    Now, the way the wind is blowing in the ICZN, this article is not likely to survive into the 5th Edition. In cases where a single, gender-incorrect spelling for a species has always been used and changing it would threaten stability, it might be wise for workers to wait it out--that spelling could well be legitimized in the 5th Ed. But in the case of Koskinonodon all three spellings have already been used at various times in the literature, in combination with various generic names, so we might as well use the correct one.



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