Talk:Becklespinax

Whether or not to merge with Altispinax

Maisch has recently, in a very ingenious analysis, claimed that Altispinax is valid after all. This obviously poses the question whether the two articles should be merged. I think this would be premature for the following reasons:

A. Maisch's proposal has yet to be generally accepted. He expresses a wish that it should be so - indicating he is himself far from confident it will happen.

B. There are some elements in his line of reasoning that might easily lead to a general rejecting. He bases his argument on article 11.10. of the ICZN: Deliberate employment of misidentifications. If an author employs a specific or subspecific name for the type species of a new nominal genus-group taxon, but deliberately in the sense of a previous misidentification of it, then the author's employment of the name is deemed to denote a new nominal species and the specific name is available with its own author and date as though it were newly proposed in combination with the new genus-group name.

Maisch argues that von Huene based Altipsinax on a misidentification of the type species by Lydekker who had added the famous long-spined vertebrae to the material. There are however three potential problems with this analysis:

1. Is there a misidentification? The type of Altispinax dunkeri, a tooth, is often seen as impossible to determine, making the name a nomen dubium. But if this is so, how can it be claimed that it would be a misidentification in the sense of article 11.10. to refer the vertebrae? The essence of being a nomen dubium is after all that one cannot know whether the same animal is involved.
2. Is there a previous misidentification? Von Huene apparently thought that Lydekker had referred the vertebrae, but as Maisch himself indicates there was no explicit reference, just a mentioning of them in a context that might be interpreted as meaning that Lydekker assumed they belonged to the same species. That's a very meagre basis to build any claim of a misidentification on.
3. Is there a deliberate employment? For the name to be valid it has to be shown that von Huene deliberately used Lydekker's interpretation as a misidentification, i.e. von Huene should have thought the tooth belonged to a different animal than the vertebrae. However, he clearly did not: von Huene used A. dunkeri indirectly as a type species for the very reason that he thought it to be possible that the tooth and vertebrae were cospecific. This is confirmed by his 1926 text, in fact written before the 1923 publication but not changed by him regarding this point.

C. Even if Altispinax is valid, we cannot simply merge because in that case M. dunkeri is not A. dunkeri!--MWAK (talk) 13:04, 11 May 2016 (UTC)

Yeah, I guess I was lead to believe this was more clear-cut by the enthusiastic reception this paper got on the Dinosaur Mailing List. So yeah, will be nice to see how other researchers treat the issue henceforward. On synonyms, perhaps the issue of merging Stormbergia is less conttoversial? FunkMonk (talk) 13:16, 11 May 2016 (UTC)

I haven't read the latest articles, so I can't say whether Butler has changed his position. It seems likely, of course. Frankly, I'm never much in favour of merging genera articles: Wikipedia is not a biology textbook but an encyclopedia explaining concepts. A reader might encounter the concept Stormbergia and it is our task to succinctly inform him about it — not force him to figure out the Lesothosaurus article. And should future data lead to a "revival", why, the article is already there. Brontosaurus comes to mind :o).--MWAK (talk) 19:03, 11 May 2016 (UTC)

Yeah, but in cases where the synonymy is widely agreed upon (unlike this case), I think it would mainly create confusion... A redirect clearly says "this is the same animal". But a separate article is more ambiguous, unless the reader reads most of the text... FunkMonk (talk) 20:55, 11 May 2016 (UTC)

As a compromise, I basically did a half-megerge, copying over the (shared) history between both articles and split Megalosaurus dunkeri into its own article. We may or may not have an extra article or two covering a synonym, but this will make merging and dis-entangling them easier if either becomes necessary. Dinoguy2 (talk) 13:08, 15 May 2016 (UTC)

I fear the situation is far murkier than your account :o). You present matters as if Maisch claims that von Huene "based" his genus on the vertebrae instead of the tooth and Extrapolaris even goes as far as claiming that von Huene himself formally created a new species and designated the vertebrae as the holotype. Nothing of the sort happened. Let's again lift von Huene's original text from Maisch's article:

"The species described as M. dunkeri by Lydekker (Dames), from the English (and German) Lower Wealden, is distinguished from Megalosaurus by its enormously high neural spines in the dorsal region. I therefore propose to establish a new genus, Altispinax, for it. M. oweni (Lydekker) from the British Upper Wealden belongs to the same genus."

As you can see there is no mention anywhere of what the type specimen might be or what the status of the original tooth might be. In fact, what happens is rather straightforward. Von Huene thinks that the vertebrae are part of the hypodigm of M. dunkeri. As these vertebrae are very distinctive they warrant a new genus name: Altispinax. The combinatio nova therefore implicitly becomes Altispinax dunkeri. Nowhere does von Huene state or imply that the tooth no longer was the holotype of the species or did not belong to the same species as the vertebrae. And indeed, nowhere in his article does Maisch claim von Huene did, for the good reason that this could never be substantiated. However, Maisch seems to think that this is irrelevant. He apparently interprets article 11.10 as meaning that every time a genus has an older type species, based on a holotype, such as the tooth, to which a previous author has by mistake referred material in fact not belonging to it, and the author naming the genus deliberately confirms this reference, unaware of the fact that it is a mistake, automatically two species pop into existence. This interpretation seems flawed: article 11.10 pertains to cases where the deliberateness consists in the author being aware. Your natural reaction was to change the facts to make them conform to the real rule and so you changed the text to the extent that von Huene based Altispinax on the vertebrae deliberately excluding the tooth. But he didn't nor does Maisch say he did.--MWAK (talk) 18:16, 15 May 2016 (UTC)

"This interpretation seems flawed" to you, the editor, but aren't you looking at the info in the paper and drawing a different conclusion from that of its author? That would be OR until somebody published the interpretation you're describing. Based on the quote you posted, Huene did base the name on the vertebrae, since it does not mention the tooth but does mention the distinctive verts. Whether this counts as "basing" it in the formal sense of misidentifying the verts as the type specimen seems open to interpretation. Dinoguy2 (talk) 13:40, 17 May 2016 (UTC)

Maisch relates the "standard" account of the situation, among it the consensus that von Huene did not indicate the vertebrae as a new type specimen of M. dunkeri. He doesn't then claim that the standard story has the facts wrong, or the standard nomenclatural consequences of these facts wrong: he claims that there is an unusual extra consequence everyone else has overseen: article 11.10 would imply that a second species was created regardless. So Maisch does not claim that von Huene deliberately misidentified the vertebrae as the type specimen. He claims that simply by von Huene, deliberately but innocent of the biological facts, referring to what we presently might consider to have been a misidentification by Lydekker, article 11.10 comes into play. And that is what I called a "flawed interpretation".

Also keep in mind what Maisch wrote:

"Stovall & Langston (1950: 722), in discussing the nomenclatural status of Altispinax, arrived at the same conclusion and proposed the vertebrae figured by Owen as the type specimen of Altispinax dunkeri, a proposal, which is accepted here, as they were the first ones to actually propose a type specimen for v. Huene’s species (v. Huene tended to be exceedingly forgetful when it came to determining types for the taxa he erected)."

So, no new type specimen in 1923 according to Maisch.--MWAK (talk) 16:05, 17 May 2016 (UTC)