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PostPosted: Sat Jan 01, 2011 11:23 am 
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Hi Dave,

As always, you have put your finger on the point very precisely:

Quote:
How common is it for the specialists in techniques, to have their own intimate knowledge of the critters themselves, though ?


It is relatively uncommon, it comes from years of experience and personal contact with, in this instance, the fishes and the actual measurements. Not just the hobbyist that "thinks" that these fishes are different, but those scientists that have done actual measurements themselves and therefore know what to look for, so we are talking about persons such as Kullander that have done very little else than study these fishes all their lives long. Someone that has just started studying these fishes, even a Ph D student that has studied such fishes, just simply does not have the experience to be able to have this knowledge. What I am also very wary about are the new generation molecular biologists or persons that do the DNA sequence determinations who all of a sudden decide that the previous morphological assessments can now be replaced by DNA sequences, this is just not good enough. I maintain that scientists that wants to lay claim to have such "intimate knowledge" are only those that have gone into the field and have developed a feel for the critters and the environment in which the critters occur.

Quote:
and if it all boils down to gut feelings and subjective "feelings", we'd be better off just taking polls.


On this point, my comment is a categorical "NO", you need to have that specialist knowledge that you have just referred to before and that is something very special.

These are very valid points that you have made here, Dave, thanks for making them.

Kind regards,

Dirk

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PostPosted: Sat Jan 01, 2011 11:41 am 
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Dirk, I wonder if you have easy access to tell how many altum and scalare Kullander looked at for his findings on scale counts and so on, and how many locations he used ?

Quote:
As always, you have put your finger on the point very precisely
My theory is that if you point your finger at enough places, you end up doing that eventually :)

His findings are then used to determine species, in later studies. Newest study cites Kullander 1986 and 2003.


We see that altum are shorter-bodied than scalare. Not relatively, compared to height, but measured actually shorter.

It would be interesting if he didn't really have much evidence.

Understandably because of the nature of the Lopez-Fernandez' type of investigation including Pterophyllum, using as few angelfish as 3, is possible, in order to answer some questions.

However, when essentially all later works will be using the "Kullander Report" measurements , as a basis for First Step conclusions ( "binning") in phylogenetics work, you'd have to think that the angelfish were sampled far up and down the rivers by Kullander '86 or '03, to find out if variance is there . In particular you'd want to sample the locations we know have extreme scalare , and the locations for correctly collected Orinoco ( or guaranteed ) Pterophyllum altum.

Through acceptance of Kullander's findings as a whole, it brings acceptance for "no overlap of the critical
object of measurement, between species".

So I wonder about the number of locations and fish that were involved in that particular finding by Kullander.

Kullander, Sven O. (1986), "Guide to South American Cichlids," Aqualog IV.

Kullander S. O. (1986 ) "Cichlid fishes of the Amazon River drainage of Peru." Swedish Museum of Natural History.

Kullander, Sven O. (1998), "A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes)," in Malabarba, L., et al. (eds), Phylogeny and Classification of Neotropical Fishes, pp. 461-498.

And the 2003 checklist. It says
Quote:
Pterophyllum altum Pellegrin, 1903
Pterophyllum altum Pellegrin, 1903: 125. Type locality: Atabapo
(Orénoque). Syntypes: BMNH 1904.6.28.2-3 [ex MNHN] (2
spms.); MHNLR P.261 (1); MNHN 1887-571 to 574 (4), 1887-
579 and 580 (14 spms.)
Maximum length: 6.5 cm SL
Distribution: South America: Amazon River


When checking with Burgess after Shultz with the "new" information from Axelrod, we see that the uppermost Rio Negro populations have higher fin ray variance and higher COUNTS, on average than the Atabapo Orinoco fish. Orinoco fish had slightly higher average scale counts. (but not nearly as high as Kullander's).

The fin and ray counts evidences are contradicted clearly by the Kullander review, it seems.

Which brings us back to the question . How many locales and specimens did Kullander use ?


Last edited by rag on Sat Jan 01, 2011 11:47 pm, edited 4 times in total.

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PostPosted: Sat Jan 01, 2011 9:18 pm 
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Dirk Bellstedt wrote:
Hi Dave,



Quote:
How common is it for the specialists in techniques, to have their own intimate knowledge of the critters themselves, though ?


It is relatively uncommon, it comes from years of experience and personal contact with, in this instance, the fishes and the actual measurements. Not just the hobbyist that "thinks" that these fishes are different, but those scientists that have done actual measurements themselves and therefore know what to look for, so we are talking about persons such as Kullander that have done very little else than study these fishes all their lives long. Someone that has just started studying these fishes, even a Ph D student that has studied such fishes, just simply does not have the experience to be able to have this knowledge. What I am also very wary about are the new generation molecular biologists or persons that do the DNA sequence determinations who all of a sudden decide that the previous morphological assessments can now be replaced by DNA sequences, this is just not good enough. I maintain that scientists that wants to lay claim to have such "intimate knowledge" are only those that have gone into the field and have developed a feel for the critters and the environment in which the critters occur.

Quote:
and if it all boils down to gut feelings and subjective "feelings", we'd be better off just taking polls.


On this point, my comment is a categorical "NO", you need to have that specialist knowledge that you have just referred to before and that is something very special.

These are very valid points that you have made here, Dave, thanks for making them.

Kind regards,

Dirk
Dirk, the question of Kullander evidences aside, this is interesting because we have been wondering what a reverse engineering of the morhpomapping and analysis would reveal.

Exactly what you said - that when we develop an affinity for a subject, we might see and compare things that we do not consciously know we see and compare.

At least, even if we know, we might have a hard time describing what we are thinking; e.g.I might notice the arc of the edge of the caudal fin is different from altum to scalare, but I still have not been able to give the nuance of what the arc does as it changes from convex to concave, with the various fish postures.

Be that as it may, give 3 or 4 tail photos and we can say "That's not the fish you are looking to buy as an altum."


So in Natasha's study, we have wondered "What, about the fish, is the first principal component dealing with or drawing from or finding most variance in ?"


Last edited by rag on Sat Jan 01, 2011 11:41 pm, edited 1 time in total.

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PostPosted: Sat Jan 01, 2011 11:17 pm 
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Hi Dave,

I have tried to access Kullander S. O. (1986 ) "Cichlid fishes of the Amazon River drainage of Peru." Swedish Museum of Natural History but I cannot find an electronic edition, so I cannot see how many specimens Kullander actually assessed. At the moment our university library is closed because of the vacation period here (hot summer holidays!), so I cannot request a hard copy. However, I am sure that I should be able to get a copy and then we can follow up on how many specimens were actually assessed.

Your comment about Natasha Meliciano reminded me to go and have a look at her research results again, and these are actually very interesting in the context of this thread. She has done a principal component analysis. I actually do not know how to perform such as analysis, but what I do know is that the analysis takes all the data of all the morphological measurements and uses this to generate these "principle components" which have no units, in other words these are not graphs of the one or the other measurements relative to one another, but rather a cumulative measure. The objective of such analyses is specifically to try to identify groups and by groups I mean groups of dots of individuals, say scalare Santa Isabel, that are separate from other groups of dots. What you see is that there is overlap between altum and scalare, which actually implies that these species cannot be separated by morphological measurements alone. What you also see from Natasha's graphs though is that it is the Santa Isabel and Boa Vista populations that cause the overlap. If the individual specimens that gave these points on this graph were to be found to be hybrid then she would have been able to separate scalare and altum, but this was not done. If DNA data could now perhaps be used to identify the hybrids, then we could perhaps resolve the situation because it would give you a scientific reason to not use the morphometric measurements of the hybrid individuals. Maybe they will re-assess the data again later. I still think it is an excellent start and they are clearly trying to get a better picture.

So for the moment we will still have to stay with:

Quote:
give 3 or 4 tail photos and we can say "That's not the fish you are looking to buy as altum."


Kind regards,

Dirk

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PostPosted: Sun Jan 02, 2011 12:11 am 
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Dirk Bellstedt wrote:
Hi Dave,

I have tried to access Kullander S. O. (1986 ) "Cichlid fishes of the Amazon River drainage of Peru." Swedish Museum of Natural History but I cannot find an electronic edition, so I cannot see how many specimens Kullander actually assessed. At the moment our university library is closed because of the vacation period here (hot summer holidays!), so I cannot request a hard copy. However, I am sure that I should be able to get a copy and then we can follow up on how many specimens were actually assessed.
That would be great. We must know the base that our suppositions spring from. Here I'm having some fun with your paragraph

Quote:
Your comment about Natasha Meliciano reminded me to go and have a look at her research results again, and these are actually very interesting in the context of this thread. She has done a principal component analysis. I actually do not know how to perform such as analysis, but what I do know is that the analysis takes all the data of all the morphological measurements and uses this to generate these "principle components" which have no units, in other words these are not graphs of the one or the other measurements relative to one another, but rather a cumulative measure. The objective of such analyses is specifically to try to identify groups and by groups I mean groups of dots of individuals, say scalare Santa Isabel, that are separate from other groups of dots. What you see is that there is overlap between altum and scalare
as defined by Kullander
Quote:
, which actually implies that these species cannot be separated by morphological measurements alone
... after reading Kullander



:P


Quote:
. What you also see from Natasha's graphs though is that it is the Santa Isabel and Boa Vista populations that cause the overlap. If the individual specimens that gave these points on this graph were to be found to be hybrid then she would have been able to separate scalare and altum, but this was not done. If DNA data could now perhaps be used to identify the hybrids, then we could perhaps resolve the situation because it would give you a scientific reason to not use the morphometric measurements of the hybrid individuals. Maybe they will re-assess the data again later. I still think it is an excellent start and they are clearly trying to get a better picture.
... or clearly trying to better paint a picture. All 3 species were identified a priori, as Brazilian.
Quote:
So for the moment we will still have to stay with:

Quote:
give 3 or 4 tail photos and we can say "That's not the fish you are looking to buy as altum."


Kind regards,

Dirk
Thanks Dirk.


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PostPosted: Sun Jan 02, 2011 12:20 am 
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Hi Dave,

Yes, I agree with your usual cryptic comments. :wink:

Let us see what Kullander has to say, or rather, what he has measured....

Kind regards,

Dirk

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PostPosted: Sun Jan 02, 2011 12:47 am 
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Quote:
... when essentially all later works will be using the "Kullander Report" measurements , as a basis for First Step conclusions ( "binning") in phylogenetics work....correctly collected Orinoco ( or guaranteed ) Pterophyllum altum...
So I wonder about the number of locations and fish that were involved....

And the 2003 checklist. It says
Quote:
Pterophyllum altum Pellegrin, 1903
Pterophyllum altum Pellegrin, 1903: 125. Type locality: Atabapo
(Orénoque). Syntypes: BMNH 1904.6.28.2-3 [ex MNHN] (2
spms.); MHNLR P.261 (1); MNHN 1887-571 to 574 (4), 1887-
579 and 580 (14 spms.)
Maximum length: 6.5 cm SL
Distribution: South America: Amazon River


so the finger points to this 6.5 cm measurement as mentioned in Natasha's study, as coming from the specimens mentioned directly above.
I can try to check the specimens as to their collection location.


From the Swedish N.H. Museum site
Quote:
Primary types
Pterophyllum altum. Syntypes, MNHN 87-571-574, 4: 58.6-70.1 mm SL; MNHN 87-579, 5: 59.9-63.0 mm SL; MNHN 87-580, 5: 41.0-61.2 mm SL; BMNH 1904.6.28.2-3, 2: 59.0-60.3 mm SL. Orénoque. No date. Chaffanjon.
Plataxoides leopoldi. Holotype, IRSNB 649, 44 mm SL. Furo du village de Cuia (rive gauche du Solimôes à environ 90 km en amont de Manacapuru. 24 Nov 1962. Léopold and J.P. Gosse.
Zeus scalaris. None known; possibly ZMB 1347 is part of the type series.
Platax scalaris. Holotype, ZMB 1347, ca 44 mm SL. No collecting data.
Plataxoides dumerilii. Holotype, MNHN A.254, ca. 46.8 mm SL. Para. No date. F. de Castelnau
Pterophyllum eimekei. Syntypes, ZMB uncatalogued, 4: largest 73.5 mm SL; MNHN 29-12, 1: 53.8 mm SL. Mündung des Rio Negro in den Amazonas. No date. Ded W. Eimeke
Quote:
Identification guide to species
Pterophyllum altum has 46-48 scales in a lateral row, and notched predorsal contour.
Pterophyllum leopoldi has 27-29 scales in a lateral row, and straight predorsal contour.
Pterophyllum scalare has 30-39 scales in a lateral row, and notched predorsal contour.

and from Fishbase
http://www.fishbase.org/References/Summ ... Name=altum


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PostPosted: Sun Jan 02, 2011 2:11 am 
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Hi Dave,

With regard to the type specimen of P scalare there is this publication in German which tries to clarify this issue:

Quote:
Mitt. Mus. Nat.kd. Berl.. Zool. Reihe 78 (2002) 1, 177-182
Zur Erstbeschreibung von Pterophy llum scalare (Schultze in Lichtenstein, 1823)
(Pisces, Cichlidae)
Hans-Joachim Paepke & Ingo Schindler


The English summary gives the following:

Quote:
Until now the author of Pterophyllum scalare has been believed to be Hinrich Martin Lichtenstein 1823. But he was supported in this work by Dr. Rodig and Ferdinand Schultze. Particulary the remarks on lizards and nearly all of the descriptions of new fishes in the ,,Verzeichnis der Doubletten des Zoologischen Museums . .. Berlin .. ." were made by Ferdinand Schultze. He also brought the manuscript to the printer during Lichtenstein's temporary absence (Lichtenstein 1823). Thus the authorship of the taxon has to be cited as Schultze in Lichtenstein 1823.
In contrast to the statement by Cuvier in Cuvier & Valenciennes 1831 that their description of P1ata.x scalaris was based on a specimen out of the Bloch-collection in Berlin, we found no evidence that Bloch had such a fish in his collection. But according to our old documentation of loans,
they did borrow a specimen of Zeus scalaris from the ZMB which was later returned. During the time before 1823 in the fish collection of the ZMB were included not only the Bloch collection but also a small number of samples collected or donated by others: for example some fishes given by the museum's founder the Count von Hoffmannsegg. His fishes
were collected by his servant Friedrich Wilhelm Sieber during the time 1801 to 1812mostly in the region of Belem in eastern Brasil. Among Sieber's fishes there is a small Pterophyllurn scalare (ZMB 2833) with the place of origin ,,Brasilien, Sieber/von Hoffmannsegg." It is the only preserved member of that taxon which we can be sure was already in
our museum at the time of the description of Zeus scalaris. Therefore we recognised it as the lectotype of Zeus scalaris. Unfortunately its size and number of fin rays are not in accordance with the description of Zeus scalaris. According to the range of Sieber's activities in eastern Brasil the type locality is restricted as follow: Lower Amazon river below respectively eastward of Obidos including the delta of the Amazon river and the lower part of the Rio Tocantins near Cameta. There is a second old specimen of that taxon (ZMB 1347) also from Brad but unfortunately without details about the depositor or collector. ZMB 1347 was considered
by Kullander (1986) as representing the type series of Zeus scalaris as well as being holotype of Platax scalaris Cuvier in Cuvier & Valenciennes 1831. That is most probably correct based on the label with the note: Platax scalaris Cuv. et Val., Zeus scalaris. However due to lack of information about the depositor or collector we are not absolutly sure that ZMB 1347 is really a member of the type series of Zeus scalaris.



So the type for scalare is definitely a single specimen.

And your bottom quote tells us what the measurements should be, but are they always that? Did Natasha's measurements agree with this?

Kind regards,

Dirk

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PostPosted: Sun Jan 02, 2011 10:42 am 
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Dirk,
The way it seems to work for Natasha is that in the forward parts they mention an historical problem identified in the literature, of overlap between species for the meristic values, citing Lowe-McConnell and Kullander.

Quote:
Lowe-McConnell in 1969 (a) quoted problems on the validation of genus and the existence of overlap of meristic characters. Kullander said that in 1986 the group had a low taxonomic resolution, having as causes the lack or poor conservation of type specimens, the existence of considerable variation and species synonymous meristic characters used.


Natasha then goes on to say Kullander resolved the species in the genus, and she follows Kullander, specifying with a very short and inadequate descriptive portion plus the high scale count ( 46-48 ), and the 6.5 cm. maximum length.

The higher scale count is likely related to difference in method of counting, between Schultz and others, and Kullander.

However, no matter which methods are used, from Schultz ala mode Burgess, the upper Rio Negro fish were within 2 scales of the Atabapo (Orinoco site) average. This is impossible if the Atabapo fish are up at 46 minimum-48 maximum scales and scalare are at 30 to 39 max... unless by definition upper Rio Negro are hybrid. They are within 2 scales of Atabapo , from Burgess/Shultz.

*So she bins the fish according to Kullander*

Quote:
your bottom quote tells us what the measurements should be, but are they always that? Did Natasha's measurements agree with this?
Natasha does not tell. No response to request for the Supplementary Information.

I imagine it goes like this: any fish over 6.5 cm altum maximum but under 7 cm, is then not altum, but scalare, and any fish over 7.5 cm. maximum, was not an angelfish.

Luckily, smallish is cheaper to buy, more plentiful, easier to catch, so probably all were smallish specimens.... :)

Later, in conclusion, she again mentions the historical problem as outlined in literature, but intimates that all has been resolved.


So she talks about the problem fore and aft, several times, and claims it is resolved anyway as everything matches up ( bins to molecules).

That's my take from memory, but I'll get the quotes

Quote:
P. altum

(Location type: upper Rio Orinoco /City of Atabapo): representatives of this species have a body more triangular, more vertical bars large, pre-dorsal outline more visible, more scales (46-48 ) along the lateral line and length Standard (CP) of 6.5 cm.

Its distribution includes the upper Rio Negro (Amazon basin) and high in regions of the Orinoco River
Colombia and Venezuela, preferably in black and clean water (Lowe-McConnell,

Quote:
P. scalare

(Location type: location unknown) is the most studied among all known species and
well appreciated among the ornamental fish.

Displays 7.5 cm standard length (SL), 30-39 scales in along the lateral line and the slot in the predorsal contour near the snout, with less apparent black mark at the base of the dorsal fin cited in above description.

Their geographical distribution covers the Amazon basin in Peru, Brazil, Colombia along the rivers Ucayali, , Amazonas (to Bethlehem), Middle Rio Negro and Madeira rivers and White.

They are also found in the Araguaia River (Tocantins state) and between Oiapoque state of Amapa (BR) and French Guiana, in the Essequibo River in Guyana and was introduced recently in Suriname. (Lowe-McConnell, 1969th; Kullander, 1986, 2003) (Figure 2 and 5).




Natasha states it as 6.5 cm length "standard" ( "CP" ) , whereas Kullander apparently has it as "maximum" according to his institution's site.


Last edited by rag on Mon Jan 03, 2011 4:40 pm, edited 2 times in total.

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PostPosted: Sun Jan 02, 2011 11:47 am 
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Dave,

It is difficult when catching an angelfish in nature for the first time to decide that this fish is actually adult, which is exactly the problem that the first descriptions hit, I mean if I was the first person to see an angelfish, I think I would have been pretty excited.

As scales can grow as the fishes get older, I would place a greater value on scale counts than on maximum length which is very dependent on age, nutrition and locality.

So the bottom line is that you hit these problems that you have mentioned that you cannot actually solve:

Quote:
The higher scale count is likely related to difference in method of counting, between Schultz and others, and Kullander.

However, no matter which methods are used, from Schultz ala mode Burgess, the upper Rio Negro fish were within 2 scales of the Atabapo (Orinoco site) average. This is impossible if the Atabapo fish are up at 48 scales and scalare are at 40 max.


What this really tells us is that morphological measurements have a level of subjectiveness in how they are interpreted, and unless all agree on the interpretation, the data is not comparable and therefore does not allow us to delineate a species without a measure of subjectiveness. This is unfortunate because I actually believe that if all the morphological data were interpreted in the same way it would give a meaningful answer with regard to species delimitation. So, the scientists that perform these measurements need to agree on how they do this, and then they need to show us the data to prove their case for the clear separation of the different species. Whether you are a scientist or a lay person, it is not clear at the moment as far as I am concerned.

Again what this leads us to is that the identification of species of angelfish still remains far too subjective. Not a good state of affairs.

Kind regards,

Dirk

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Last edited by Dirk Bellstedt on Sun Jan 02, 2011 11:56 am, edited 1 time in total.

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PostPosted: Sun Jan 02, 2011 11:55 am 
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These people cannot deal with a problem like counting scales, yet we are to believe the results of their Procrustean Bed Treatment :P

All it takes is to finding one fish counted by Shultz or Burgess and you know his method and so can reconcile everything...except the fact that upper Rio Negro fish are higher on the other things and only 2 lower, on scales, than Atabapo fish.

I catch the smell of ex post ante binning work. That is, is we get an historical average, or standard, then new specimens are binned according to averages which are treated as though limits - instead of using the raw limits for categorization/binning.


Last edited by rag on Sun Jan 02, 2011 12:51 pm, edited 3 times in total.

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PostPosted: Sun Jan 02, 2011 12:02 pm 
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Hi Dave,

You were too fast with your reply, I still wanted to add something.....

but now I fear that I am a little bit lost myself, what is this:

Quote:

Procrustean Bed Treatment



What I wanted to add was that the molecular data will not help us to resolve this situation unless the morphological measurements are agreed on as well.

Kind regards,

Dirk

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PostPosted: Sun Jan 02, 2011 12:11 pm 
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Dirk Bellstedt wrote:
Hi Dave,

You were too fast with your reply, I still wanted to add something.....

but now I fear that I am a little bit lost myself, what is this:

Quote:

Procrustean Bed Treatment



What I wanted to add was that the molecular data will not help us to resolve this situation unless the morphological measurements are agreed on as well.

Kind regards,

Dirk
I had added that myself with some awkward smarty pants wording, but I took it out..always post editing as I second guess myself.

I was saying that one cannot reconcile a logical paradox merely by showing some molecular data.

However, I'm thinking/guessing/ recalling that Kullander did resolve some of this historical stuff.

Not enough unless Burgess/Shultz/Kullander numbering or counting differences in method and resulting count, are totally reconciled or explained somehow.
Collation error. Something.

It's really simple if we take Kullander at face value. Upper Rio Negro are hybrids with forms more extreme in some features ( fin rays) than either parental stock, possibly due to known hybridization effects.

Take a poll, it is better than the "Science".


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PostPosted: Sun Jan 02, 2011 12:24 pm 
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Dirk Bellstedt wrote:
Hi Dave,

You were too fast with your reply, I still wanted to add something.....

but now I fear that I am a little bit lost myself, what is this:

Quote:

Procrustean Bed Treatment



Procrustes stretched his guests at the inn, or lopped off bits, to fit the bed.

The scientists here used a program called "Procrustes"


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PostPosted: Sun Jan 02, 2011 12:59 pm 
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If I might draw an analogy for what was done ( done - at least, in my mind this is what was done :wink: ), using human races:

Suppose we average adult human heights. Blacks , say, average a bit higher than Whites and hold the height record . However, both races vary so hugely within, that this variance is equal. There are very short and very tall individuals in both races. In all, for this standardization procedure, we used only up to 25 "random adult" people, of each race.



Now we get a standard max height for the races. We then take 200 specimens drawn only from our own country, according to height.

Then we use the Procrustean Bed to find differences between these "races" ( individuals binned according to each individual's height with reference to average height for each race).

Then we look at the genes.
One conclusion we draw is that with these 2 races originating in our country, water probably makes a big difference. :lol:


Last edited by rag on Sun Jan 02, 2011 2:09 pm, edited 1 time in total.

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