Pharyngula

Posted by: Lago | July 14, 2008 5:58 PM

There are several different names given to the same set of bones in the wrists in tetrapods. For example, there are standard type names like Shubin gave that are distal, proximal ulnare and so on, and there are ones for mammals in general, which are sometimes shared with the ones given for humans in general.

This all comes from a time when different groups in different regions and disciplines named the same homologous bones by different names. Some people familiar with human wrist bone names alone often get confused and think the same bones are different based on the different names. The idiot mentioned above does not grasp that Shubin is using the same names for both Tiktaalik, as well as tetrapods in general because he is confused on this...

Again, ignorance is bliss...

Posted by: OctoberMermaid | July 14, 2008 6:01 PM

Jesus, even I knew what "eponymous" meant and I'm not even a lawyer OR a scientist.

Crazy!

What a dope.

Posted by: Sili | July 14, 2008 6:12 PM

It doesn't work Blake. I'm just a bit slow working my way through the QM preliminaries (it's been too long). What really slows me down, though, are all those bloody links.

Re Lazy Cuskin:

Landlady showing flat to promising young author:
- So have I read anything you've written? Your name doesn't ring any bells.
- Oh. I use a pseudonym.
- I don't care, young man. As long as she's out of here by ten!

Posted by: Lledowyn | July 14, 2008 6:14 PM

Amazing. Little Casey finds a few words that he can't understand, and instead of going to a dictionary, or some other source to find out what they mean, he throws up his hands, calls it "jargon," and complains that the article doesn't explain anything. The label IDiot fits rather well to this fellow.

Posted by: ERV | July 14, 2008 6:17 PM

In all fairness, 'eponymous' is a hard word.

But I cant believe Luskin passed kindergarten after this:

"Digits are part of fingers or toes that have a grasping capability. It's tough to grasp something with one bone in your finger, so these don't deserve to be called digits."

Posted by: Reed A. Cartwright | July 14, 2008 6:22 PM

Damn it, PZ! Why are you putting all these atrocious science posts on your blog. I thought this was supposed to be an anti-cracker blog. You risk alienating your anti-cracker readers with stuff like this.

Posted by: Orac | July 14, 2008 6:23 PM

As a physician, I'm particularly amused by this. Lots of human body parts have eponyms, but over the last two decades there has been a real effort to do away with them. However, physicians are resisting, apparently having a hard time saying things like "uterine tubes" instead of "Fallopian tubes."

Surgeons especially love eponyms, because it means they get to name anatomic structures after surgeons, pathologists, or anatomists. Consequently, we have Cooper's ligament, the foramen of Winslow, Gerota's fascia, the ligament of Treitz, Meckel's diverticulum, Zenker's diverticulum, and all manner of other bits of anatomy or pathology named after their discoverers.

Posted by: JohnB | July 14, 2008 6:24 PM

Poor Luskin, the Emily Litella of creationism. I don't think he'll follow this up with a sheepish "Nevermind", though.

Posted by: Holbach | July 14, 2008 6:26 PM

Screw Luskin; give him a cracker!

Posted by: Glen Davidson | July 14, 2008 6:27 PM

That's not really what "eponymous" means, however. "Synonymous", or, of course, "homologous," would work.

Glen D
http://tinyurl.com/2kxyc7

Posted by: Ric | July 14, 2008 6:32 PM

Bwahaha! That's beautiful. Luskin is a moron.

Posted by: Lord Zero | July 14, 2008 6:34 PM

Cute diagrams... its sad than their IQ are
not high enough to grasp their meaning, but
i guess i will use it as a reminder myself,
so your work its not wasted.

Posted by: Alex | July 14, 2008 6:39 PM

#21

Thanks for the link Shaden. It gave me more than a chuckle.

Teh gawd peepl iz crizazie!

Posted by: Iason Ouabache | July 14, 2008 6:51 PM

This is exactly why you shouldn't send a lawyer to do a scientist's job.

Posted by: BlueIndependent | July 14, 2008 6:56 PM

@ #15:

True dat! Great compilation album.

@ #20:

I think the reason "eponymous" was chosen was because the first part of the word, "epo", refers to that which generated the part names, the "epicenter" or origin of those part "nyms" or names. Synonymous and Homologous refers to things that may serve a similar function, but are not necessarily the same thing in construct. For example, a bat can "see" with sound, which means their ears are homologous to our eyes, even though they are different forms. Shubin is saying the Tiktaalik parts are essentially the same pieces from tetrapods.

That's my understanding of what's going on, but I realize i may be off a bit.

Posted by: allonym | July 14, 2008 7:10 PM

This is exactly why you shouldn't send a lawyer to do a scientist's job.

Posted by: AdamK | July 14, 2008 7:15 PM

Glen - "Eponymous" means "named after," "synonymous" means "meaning the same thing," not "being the same word." (They don't mean the same thing. :) Synonymy is about words, not anatomical structures or other objects.)

"Homologous" means "having the same origin or function," but the author is using shorthand to identify the names of the bones, not their functions. The usage here is correct, although "eponymous" has other uses in other contexts.

Posted by: Glen Davidson | July 14, 2008 7:21 PM

I think the reason "eponymous" was chosen was because the first part of the word, "epo", refers to that which generated the part names, the "epicenter" or origin of those part "nyms" or names. Synonymous and Homologous refers to things that may serve a similar function, but are not necessarily the same thing in construct. For example, a bat can "see" with sound, which means their ears are homologous to our eyes, even though they are different forms. Shubin is saying the Tiktaalik parts are essentially the same pieces from tetrapods.

That's my understanding of what's going on, but I realize i may be off a bit.

Yes, thanks, that could well be the case. The only trouble is that "eponymous" simply does not mean that, at least not in any context in which I've seen it used. I do not believe that Shubin used the term properly, unless it has some specialized meaning to which I am not privy.

An eponym is the name of a person, whether real or fictitious, which has (or is thought to have) given rise to the name of a particular place, tribe, era, discovery, or other item. An eponymous person is the person referred to by the eponym. In contemporary English, the term eponymous is often used to mean self-titled, as in "Metallica's eponymous 'black album'". The word eponym is often used for the thing titled. Stigler's law of eponymy suggests that Eponyms are usually false, i.e., things are rarely named after the person who discovered or invented them. An aitiology is a "reverse eponym" in the sense that a legendary character is invented in order to explain a term.

I guess I could say one more thing outside of the meaning of "eponymous"--Luskin, if he presumes to speak on these matter, should know that the same terms are used across related organisms. He doesn't have to rely on the meaning of "eponymous" to understand, except that he regularly "discusses" what he does not understand.

Glen D
http://tinyurl.com/2kxyc7

Posted by: mayhempix | July 14, 2008 7:26 PM

Luskin needs a "Wrist Watch" that tells him what century this is.

Posted by: Glen Davidson | July 14, 2008 7:31 PM

Glen - "Eponymous" means "named after,"

Yes, that is why I noted that it is not correct.

"synonymous" means "meaning the same thing," not "being the same word." (They don't mean the same thing. :) Synonymy is about words, not anatomical structures or other objects.)

No, it is not exclusively about words. One may say "the university is synonymous with learning", which loosely means that the same word can be used for the physical existence of the school as well as for "learning". It's not necessarily true, of course, but that would be what is meant. That's because the etymology is not entirely divorced from all of its meanings.

Hence one could claim that bones are synonymous, and be within that meaning of "synonymous". It is not how the term would ordinarily be used, of course.

"Homologous" means "having the same origin or function," but the author is using shorthand to identify the names of the bones, not their functions. The usage here is correct, although "eponymous" has other uses in other contexts.

It may be correct, however I have not seen it used in that way before (a short check on Nature's website only showed Shubin using the word in that way, though it was only a short check). I know what he means by it, of course, but the bones are not given the same name because one wrist bone is named for a wrist bone in another species, but because they are the "same bones".

Glen D
http://tinyurl.com/2kxyc7

Posted by: janet | July 14, 2008 7:48 PM

Glen is correct: this is not a proper usage of "eponymous." Yes, the word does mean "named after," but it refers to the *person* after whom an object, literary work, etc., is named.

From my American Heritage dictionary: "Eponym. n. 1. A person whose name is or is thought to be the source of the name of something, such as a city, country, or era. 2. Medicine. A name of a drug, structure, or disease based on or derived from the name of a person." That's the entire definition.

So if, for example, you were discussing Alzheimer's disease, it would be proper to refer to "the eponymous discoverer of the disease."

Still, it should have been obvious what Shubin meant.

Posted by: Martin | July 14, 2008 7:54 PM

These clowns at the DI would be much funnier if more people would realize that they are performance artists with little talent and no expertise, except in lying and tripping over their own shoes

I demand you take back this slanderous statement right away! Discovery Institute are clearly rubbish at lying as well (though, granted, quite adept at tripping over their own shoes).

Posted by: John Pieret | July 14, 2008 7:56 PM

Have you seen his previous article

http://www.evolutionnews.org/2008/07/national_geographic_uses_fish.html

... where he apparently thinks (admittedly it's hard to tell with someone so confused) that both flatfish eyes migrate from the side of the head onto the the "top" of the head?

The fossils that were found were little fish fossils that are species of flatfish. Known living species of flatfish (like the yummy flounder, sole, or halibut) are unique in that as adults, the eyes sit on the top of the head, rather than on the sides of the head, like most fish. But young flatfish DO have eyes on the sides of the head--their eyes migrate to the top during development. Now observe the meager scope of evolutionary change allegedly documented by these fossils: they have some skull features similar to known living flatfish, but their eyes remain on the sides of the head, like normal fish. As the abstract of the paper says, "Most remarkably, orbital migration was incomplete in Amphistium and Heteronectes, with eyes remaining on opposite sides of the head in post-metamorphic individuals."

Forgive me if I'm not highly impressed with the degree of "evolution" documented by these fossils. Do they explain how halibut and sole evolved to have eyes on the top? Not really. The eyes on these fossils weren't in an "intermediate" location, halfway from the sides to the top. Their eyes are on the sides on the side of the head, like normal fish. The only interesting thing about these fossils, as far as evolution is concerned, is that they share some other skull features--the asymmetrical eye sockets--that are unique to "eyes on top" flatfish.

I've been meaning to blog about it but I'm not sure it's right to make fun of the handicapped.

Posted by: Glen Davidson | July 14, 2008 7:59 PM

Glen is correct: this is not a proper usage of "eponymous." Yes, the word does mean "named after," but it refers to the *person* after whom an object, literary work, etc., is named.

In science journals, however, "eponymous" is indeed sometimes used for entities named after other (sometimes non-personal) entities. There, at least, it need not be named after a person.

So to name "wrist bones" after the "wrist" is what he means, and it does fit with scientific usage. It's confusing, because there seems no reason to bring up the origin of the term "wrist bones" where he does, and PZ did write in a manner that would suggest that "eponymous" means homologous (like I said, that may not have been his intention).

But yes, Shubin is telling us the obvious fact that "wrist bones" are named after the "wrist" in tetrapods.

Glen D
http://tinyurl.com/2kxyc7

Posted by: hje | July 14, 2008 8:04 PM

Reminds me of the phrase used by a character on Kids in the Hall: "Where do you idiots come from to get your heads so terribly crushed!"

Posted by: ice9 | July 14, 2008 8:13 PM

'Eponymous' isn't Luskin's only diction sin. He later mocks Shubin's use of the word "presage", even including a dictionary definition and link to criticise the word choice. Luskin kindly provides the M-W definition of 'presage'--but he chooses the noun definition, though Shubin uses it as a verb. Luskin no doubt wanted the occult connotation in the noun definition (he later flippantly substitutes "foreshadow"). 'Presage' is most commonly used as a verb, but, sadly for Mr. Luskin, Merriam Webster gives us "predict" as a synonym and it makes perfect sense. The verb definition requires another click to get. Casey Luskin, take your choice: Lazy, stupid, corrupt, or some combination of all three.

And, re eponymous--strict definition requires that it be the name of a person associated with the thing that becomes the commonly used name of the thing--diesel, tarmac, macintosh, etc. But in common usage the word finds another role: specific becomes generic. (not quite the same as synecdoche, substituting specific for generic.) I grew up calling pop 'coke'--leading lots of waitresses to ask me this question: "What kind of coke do you want, honey? We got Teem, Seven-up, Nehi Orange, and Royal Crown." (for one of my favorite infographics of all time, see http://infosthetics.com/archives/2005/08/pop_versus_soda.html)
Given the implied passage of time and difference in the organisms, it seems that eponymous is actually a creative and thoughtful way of referring to the bones as analogous and same-named.

ice

Posted by: DaveH | July 14, 2008 8:14 PM

I think that Shubin (et al) is stressing that the bones in Tiktaalik have the same articular relations as those of the tetrapods and therefore he (et al) named them after those bones. Therefore, in this case, they are eponymous.
Slightly unusual use of the word (the eponymous fibula is a Roman cloak-pin shaped like a bird's legbone) but legitimate IMHO.

Posted by: ice9 | July 14, 2008 8:19 PM

sorry, the pop vs. soda map link went presage eponymous.

try this

http://popvssoda.com:2998/countystats/total-county.html

ice

Posted by: Mister Troll | July 14, 2008 8:27 PM

Junior Woodchuck? That's an insult to the Junior Woodchucks!

Actually, you should seize the Junior Woodchucks mantle for yourself. The organization (at least in the Barks/Rosa strips; I don't really remember Duck Tales but don't really want to) always went around awarding buckets of medals (literally) and titles galore. Best organization ever.

PZ could be the G.R.E.A.T.O.C.T.O.P.U.S., the Guru of Reality-based Evolution And Taster Of Crackers That Orthodoxy Prevents Us from Satirizing.

Well, not bad for a first start.

Posted by: pcarini | July 14, 2008 8:41 PM

Why can't any of these goddamned Lawyers For Jesus learn to read for comprehension?

Posted by: Glen Davidson | July 14, 2008 8:51 PM

The intermedium and ulnare of Tiktaalik have homologues to eponymous wrist bones of tetrapods with which they share similar positions and articular relations.

Yes, back to this tiresome passage again. It's not a well done passage, really, but I should have had it directly before me when I commented on it.

He really isn't using the word "eponymous" correctly there, because he's suggesting that the "homologous bones" of Tiktaalik are named after "wrist bones of tetrapods" (and I shouldn't have read it as I did before, even though it makes the use of "eponymous" correct that way).

Yet because the bones are not "named after" other tetrapod wrist bones, but are given the same name because they are genetically "the same" bones, they are not "eponymous" in the ordinary scientific sense. They're merely homologous, or synapomorphic.

To say that they are "eponymous" would suggest that they are not homologous, only named after similar organs. That is to say, one might indeed have "eponymous" convergent organs, where unrelated organs are named after similar but genetically different organs. Parts of bat wings and bird wings might thereby be "eponymous" (as are the "wings" themselves), because they would not be homologous (some homologies exist).

I cannot see any real justification for saying that the bones are "eponymous", when they are in fact homologous. To be fair, he no doubt used the term in order to point out where the terms are coming from--previously known organisms. Unfortunately, using the term as he does would tend to suggest that the bones are not "the same bones" due to evolutionary relationships.

It would be like saying that the anatomy of chimp body hair is eponymous with that of human body hair. But no, chimp body hair anatomy is not "named after" the anatomy of human body hair, it is named the same because it is "the same" as we mean that phylogenetically and taxonomically. To use "eponymous" as he does is confusing, unless it were reserved for terms used for convergent but non-homologous "naming for."

For example, the fin of a dolphin and a fin of a fish might be eponymous, because they are not "the same" evolved parts (though homologies occur), rather the dolphin's fin is eponymous with the fish's fin (well, that succession seems likely to me)

Glen D
http://tinyurl.com/2kxyc7

Posted by: inkadu | July 14, 2008 9:00 PM

Another raging internet battle between "homologous" and "eponymous." Lets see if this one breaks science blogs.

And as a reminder to all you young'ns out there (though obviously people who remember Orange Nehi are excluded): Junior Woodchucks in the Disney universe are homologous to the Cub Scouts. I'm just old enough to remember that from watching "Duck Tales" in the 80's.

Also, I'm slightly dissapointed that nobody has posted a WHOIS search on Luskin yet during this entire thread -- no IP address, no originating server, nothing. I'm calling 1800FLOWERS to complain about this.

Posted by: pcarini | July 14, 2008 9:12 PM

Me @ 60

Why can't any of these goddamned Lawyers For Jesus learn to read for comprehension?

Bah. I thought I had totally just coined the term. Damn you wowbagger!

Posted by: epsilon | July 14, 2008 9:19 PM

"If most of the drive-by trolls aren't capable of scrolling down the page, maybe a couple sciencey posts (reposts from the archives?) will frighten them off. I generally do that with math-heavy posts to drive away the extra readers I pick up after I've been Pharyngulated. . . ."

Call me a geek, but that made me go check out your site. I don't think it's possible to have too much math for me.

Posted by: Glen Davidson | July 14, 2008 9:32 PM

For example, the fin of a dolphin and a fin of a fish might be eponymous, because they are not "the same" evolved parts (though homologies occur),

Small issue: Only the "pectoral fins" (as they're sometimes called) of dolphins have much homology with fish (pectoral) fins, at least so far as I know. The dorsal fins of dolphins, which are more regularly called "fins", would not seem to be homologous with those of fishes in any way worth mentioning.

Glen D
http://tinyurl.com/2kxyc7

Posted by: Ann | July 14, 2008 9:49 PM

Returning (or turning for the first time) to the science itself, rather than the language, I'd like to ask some very basic questions. I'm fascinated by evolution and genetics--although I'm a non-scientist--and I'm just trying to understand the arguments more thoroughly. An illustration of the four legs of a table and of a dog, for instance, would tell us something about geometric stability (or possibly symmetry), but we couldn't claim a relationship.

If these bones were not given the same names, and if the illustrations were not color-coded, what aspects of the bones themselves suggest an evolutionary relationship, if indeed such a relationship is being implied?

My limited knowledge produces only a circular argument: "They're the same bones so we've given them the same names and color-coded them. How do we know they're the same bones? They have the same names and colors!"

So what is it about, say, the intermedia of Panderichthys and Limnoscelis that tells us they're the "same" bones? Or perhaps more basically, how is "same" being defined here?

Thanks in advance for any enlightenment!

Posted by: pcarini | July 14, 2008 10:02 PM

@Ann:

I don't know the technical details myself, but the article the images came from originally would be a good starting point:

http://www.devoniantimes.org/opportunity/tetrapodsAnswer.html

I particularly recommend the "Fins to Limbs" section, and the references at the bottom of the article - especially the "Image Credits" which will tell you which of those papers contain the most pertinent information.

Posted by: Glen Davidson | July 14, 2008 10:31 PM

If these bones were not given the same names, and if the illustrations were not color-coded, what aspects of the bones themselves suggest an evolutionary relationship, if indeed such a relationship is being implied?

It is not always easy to tell which are homologous. For a long time there was a dispute over which digits show up in bird wings. Here's just the abstract of one study that came to the conclusion that the most anterior digit corresponds to digit 1, rather than to digit 2 in other amniotes:

Vargas and Fallon (2005. J Exp Zool (Mol Dev Evol) 304B:86-90) propose that Hox gene expression patterns indicate that the most anterior digit in bird wings is homologous to digit 1 rather than to digit 2 in other amniotes. This interpretation is based on the presence of Hoxd13 expression in combination with the absence of Hoxd.12 expression in the second digit condensation from which this digit develops (the first condensation is transiently present). This is a pattern that is similar to that in the developing digit 1 of the chicken foot and the mouse hand and foot. They have tested this new hypothesis by analysing Hoxd.12 and Hoxdl3 expression patterns in two polydactylous chicken mutants, Silkie and talpid2. They conclude that the data support the notion that the most anterior remaining digit of the bird wing is homologous to digit 1 in other amniotes either in a standard phylogenetic sense, or alternatively in a (limited) developmental sense in agreement with the Frameshift Hypothesis of Wagner and Gautier (1999, i.e., that the developmental pathway is homologous to the one that leads to a digit 1 identity in other amniotes, although it occurs in the second instead of the first digit condensation). We argue that the Hoxdl2 and Hoxd13 expression patterns found for these and other limb mutants do not allow distinguishing between the hypothesis of Vargas and Fallon (2005. J Exp Zool (Mol Dev Evol) 304B:86-90) and the alternative one, i.e., the most anterior digit in bird wings is homologous to digit 2 in other amniotes, in a phylogenetic or developmental sense. Therefore, at the moment the data on limb mutants does not present a challenge to the hypothesis, based on other developmental data (Holmgren, 1955. Acta Zool 36:243-328; Hinchliffe, 1984. In: Hecht M, Ostrom JH, Viohl G, Wellnhofer P, editors. The beginnings of birds. Eichstätt: Freunde des Jura-Museum. p 141-147; Burke and Feduccia, 1997. Science 278:666-668; Kundrát et al., 2002. J Exp Zool (Mol Dev Evol) 294B:151-159; Larsson and Wagner, 2002. J Exp Zool (Mol Dev Evol) 294B:146-151; Feduccia and Nowicki, 2002. Naturwissenschaften 89:391-393), that the digits of bird wings are homologous to digits 2,3,4 in amniotes. We recommend further testing of the hypothesis by comparing Hoxd expression patterns in different taxa.

cat.inist.fr/?aModele=afficheN&cpsidt=16878877

As you can see there, they (and many others) turned to ontogeny (embryogenesis) to come to their conclusion. Often fossils are used to support one hypothesis over another one.

Sometimes it's real easy to tell from comparing anatomies of living organisms. One could say that evolutionary theory largely came from homologies that are quite easy to understand, as in ape and human anatomy. There, one basically can just look in similar places for similar bones, with little or no ambiguity. One also would have little or no trouble deciding homologous bones between modern birds and archaeopteryx, though a few bones might be more problematic.

As you might notice in the illustrations, the humerus us quite similar in all of the tetrapods, and is somewhat similar to some of the fish humeri (? the plural). The radius is fairly easy to compare across the tetrapods, due to position and to some degree the shape. The various forms of the intermedium are not easy to identify as such, at least not for the untrained person. I would suspect that not every bone in every illustration is completely certain.

The fact is that a variety of ways are used to identify and cross-check homologies. Counting the bones is one technique used, so that if the same number of bones in a "wrist" exist in fairly closely related species, one would usually expect the same bones to exist in each "wrist".

Apparent evolutionary relationships would be considered as well. Then, as I noted previously, ontogeny is frequently used when questions of which bones are "the same" remain after comparisons of (in my example) skeletons leaves questions remaining. Often ancestral relationships are visible in the developing embryo (the pharyngula stage, esp.) which are obscured in the adult animal.

And questions remain about exactly which organ or bone is homologous with another in many cases. Likely not all questions about homologies will be answered, ever. Yet homologies were undeniable to many creationists prior to the development of evolution (creationist Owen established the idea of homology in the English-speaking world).

Glen D
http://tinyurl.com/2kxyc7