Saturday, March 6, 2010

Article 13.1.1 means Lewisuchinae/idae is doomed and that Unenlagiinae and Microraptorinae are misattributed

First, an apology to the authors of the Asilisaurus paper for implying in my previous post that a reason the named Silesauridae as a clade instead of a family was to avoid priority issues with Lewisuchinae/idae.  As pointed out on the Chinleana blog, ICZN Article 13.1.1 states a new family-level name requires a definition or diagnosis, which Paul does not provide for Lewisuchinae.  Thus it is a nomen nudum, and Silesauridae is the first validly proposed family-level name for the group.

This made me wonder how many other family-level non-neornithine theropod taxa are nomina nuda.  Specifically, Article 13 states family-level taxa named after 1930 need "a description or definition that states in words characters that are purported to differentiate the taxon" or a bibliographic reference to such a statement (note I think a phylogenetic definition counts as a definition).  They can also "be proposed expressly as a new replacement name (nomen novum) for an available name, whether required by any provision of the Code or not."  However, Article 13.2.1 states "A family-group name first published after 1930 and before 1961 which does not satisfy the provisions of Article 13.1 is available from its original publication only if it was used as valid before 2000, and also was not rejected by an author who, after 1960 and before 2000, expressly applied Article 13 of the then current editions of the Code."  Also, Article 13.5 states that if a family-level name and nominal genus are proposed in the same work, one definition/diagnosis will do.  Before 1931, the rules are less strict, and any family named from a valid genus was considered valid (Article 12.2.4).  The groups are listed as families below for simplicity, though some have only been explicitly proposed as subfamilies.

Valid due to definition/diagnoses- Herrerasauridae, Staurikosauridae, Guaibasauridae, Protoavidae, Dilophosauridae sensu Madsen and Welles 2000, Noasauridae, Velocisauridae, Abelisauridae, Carnotauridae, Streptospondylidae, Eustreptospondylidae, Torvosauridae, Baryonychidae, Irritatoridae, Sigilmassasauridae, Sinraptoridae, Metriacanthosauridae, Neovenatoridae, Giganotosauridae, Iliosuchidae, Shanshanosauridae, Albertosauridae, Sinosauropterygidae, Ornitholestidae, Bradycnemidae, Praeornithidae, Deinocheiridae, Harpymimidae, Garudimimidae, Alvarezsauridae, Parvicursoridae, Mononykidae, Alxasauridae, Therizinosauridae, Segnosauridae, Nanshiungosauridae, Caudipteridae and therefore Caudipteryidae, Elmisauridae, Avimimidae, Kuszholiidae, Ingeniidae, Saurornithoididae, Archaeornithoididae, Itemiridae, Unenlagiidae sensu Makovicky et al. 2005, Microraptoridae sensu Longrich and Currie 2009, Saurornitholestiidae, Velociraptoridae, Scansoriopterygidae, Jeholornithidae, Yandangithidae and therefore Yandangornithidae, Omnivoropterygidae, Sapeornithidae, Confuciusornithidae, Aberratiodontuidae, Cuspirostrisornithidae, Iberomesornithidae, Protopterygidae, Alexornithidae, Enantiornithidae sensu Nessov 1984, Longipterygidae, Longirostravisidae, Alethoalaornithidae, Avisauridae, Boluochidae, Concornithidae, Eoenantiornithidae, Gobipterygidae, Cathayornithidae, Liaoningornithidae, Hongshanornithidae, Patagopterygidae, Songlingornithidae, Yanornithidae, Yixianornithidae, Eurolimnornithidae, Limnornithidae Kessler and Jurcsak 1984, Zhyraornithidae, Gansuidae, Plegadornithidae, Angelinornithidae, Asiahesperornithidae, Ambiortidae.

Valid due to being named between 1931 and 1960 and used as valid before 2000- Halticosauridae, Segisauridae, Bahariasauridae, Erectopodidae, Carcharodontosauridae, Antrodemidae, Caenagnathidae, Elopterygidae.

Valid due to being named before 1931- Coelophysidae, Podokesauridae, Procompsognathidae, Ceratosauridae, Megalosauridae, Spinosauridae, Allosauridae, Labrosauridae, Dryptosauridae, Tyrannosauridae, Aublysodontidae, Deinodontidae, Coeluridae, Compsognathidae, Ornithomimidae, Oviraptoridae, Troodontidae, Dromaeosauridae, Ornithodesmidae, Archaeopterygidae, Archaeornithidae, Ichthyornithidae, Enaliornithidae, Baptornithidae, Hesperornithidae.

Invalid- Dilophosauridae Charig and Milner 1990, Acrocanthosauridae, Unquillosauridae (in a thesis), Erlikosauridae, Rahonavidae, Unenlagidae Bonaparte 1999, Microraptorinae Makovicky et al. 2005, Enantiornithidae Nessov and Borkin 1983, Sinornithidae, Chaoyangidae, Chaoyangornithidae, Limnornithidae Kessler 1984, Palaeocursornithidae, Apsaravidae.

The only ones which are commonly used today are Unenlagidae (as Unenlagiinae) and Microraptoridae (as Microraptorinae), but these should be attributed to Makovicky et al. (2005) and Longrich and Currie (2009) respectively.

Unknown, as I lack the papers- Syntarsiidae (Kalandadze and Rautian, 1991), Torvosauridae (Galton, 1985), Struthiomimidae (Ostrom, 1972), Enantiornithidae (Nessov and Borkin, 1983), Liaoxiornithidae (Hou et al., 2002), Palaeocursornithidae (Jurcsak and Kessler, 1988).
Note Torvosauridae is at least valid under Kurzanov (1989), Struthiomimidae under Kaiser (2007), and Enantiornithidae under Nessov (1984) though.  If anyone wants to send the references to me (at, I'd be grateful.


Thanks to Jerry Harris for providing a few of the references.  Torvosauridae is valid due to a diagnosis.  Palaeocursornithidae is invalid since it's just a name in a taxonomic list.  Enantiornithidae is also invalid for Nessov and Borkin 1983, since they merely refer to PO 3494 (a proximal tarsometatarsus) as being a member of that family, without comment.

Hou, Zhou, Zhang and Gu, 2002. Mesozoic birds from western Liaoning in China. ISBN 7-5381-3392-5. 120 pp.

Jensen, 1985. Uncompahgre dinosaur fauna: A preliminary report. Great Basin Naturalist. 45, 710-720.

Jurcsak and Kessler, 1988. Evolutia avifaunei pe teritoriul Romaneie. III . Filogenie si sistematica. Cistia. 18, 647-688.

Kalandadze and Rautian, 1991. Late Triassic zoogeography and reconstruction of the terrestrial tetrapod fauna of North Africa. Paleont. Journ. 1, 1-12.

Nessov and Borkin, 1983. New records of bird bones from Cretaceous of Mongolia and Middle Asia. Trudy Zoologicheskogo Instituta AN SSSR. 116, 108-110.

Ostrom, 1972. Dinosaur. in McGraw-Hill Yearbook, Science and Technology. 176-179.


  1. That is pretty good, I would have thought there would have been more (see my comment at Chinleana), but then the pre-1930 status of many commonly used names preserves them.

    I see you're already using sensu as well ;).

    I'll tackle the pseudosuchians one of these days just out of curiosity. I already know Shuvosauridae is not valid.

  2. Thanks! I'd like to see that list of pseudosuchian family validity. As for Shuvosauridae, remember Article 13.5 that states if a family-level name and nominal genus are proposed in the same work, one definition/diagnosis will do. Since Chatterjee (1993) diagnosed Shuvosaurus, that counts for Shuvosauridae as well.

  3. Caught that. Obviously I'm not as up on the ICZN as I thought. I'm currently sitting in Dr. Wann Langston's library looking though Hay's (1930)catalogue of NA vertebrates for starters. Very interesting.

  4. This is definitely one of the more contentious articles in the Code; its been suggested that a lot of commonly used names could be threatened if it was invoked more fully than it often is. For instance, many phylogenetic studies have resulted in names being given to particular clades without an explicit 'diagnosis' for the clade though it is often pretty clear in context what the intended meaning is (take a look at molecular studies of birds for the last thirty years as an example). It could be (and has been) argued that as the only part of the original description that is binding in any way is that the family name must refer to a taxon including the type genus, then designation of the type genus should be all that is necessary to establish a new family-group taxon.

    It doesn't help matters that there's a number of researchers out there that interpret 'diagnosis' or 'definition' to refer specifically to morphological diagnoses, and so regard anything explicitly defined on phylogenetic or molecular grounds only as invalid. I don't see how this argument stands up in the context of the ICZN, myself - the Code, for instance, defines a 'diagnosis' as "a statement in words that purports to give those characters which differentiate the taxon from other taxa with which it is likely to be confused" with comparable definitions for 'definition' and 'description'. Just because most 'characters' used in the past have been morphological doesn't mean that they a priori shouldn't be phylogenetic or molecular as far as I can see (it might be argued that morphological characters are better but that's a separate issue, just as 'availability' and 'validity' of taxa are separate issues).

  5. One aspect which could be problematic for a small number of cases is "statement in words" portion. Hongshanornithidae is never defined or diagnosed in sentences, but instead has a list of character state changes in the form of "15 -> 1". As in, character 15 changes to state 1. Does that count as "in words" since it could be expressed in words, or do numbers and symbols mean it's a nomen nudum?