P.cambridgei relative?

minax

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Hey conipto/Bill, I am replying to your observation on the p.regalis thread about these T's being distant relatives( p.cambridei and p.regalis). I agree, the commonality is not obvious. One thing that may have puzzled the arachnologists who described P.cambridei is that it is common for all the T's in this hemisphere to have urticating hair and P.cambridgei does not . Also no T's in p.regalis hemisphere have urticating hairs. But there is probably a similarity in the genitalia of these species; a common way for arachnologists to i.d. closely related species or find a not so obvious similarity in a species.
 

conipto

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Thanks, So we have lack of urticating hairs (rare in NW species), arboreal, and fast and mean, of course. Other than that, are most of the similarities incredibly hard to grasp without being a biology major?

Bill
 

Code Monkey

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Originally posted by conipto
Thanks, So we have lack of urticating hairs (rare in NW species), arboreal, and fast and mean, of course. Other than that, are most of the similarities incredibly hard to grasp without being a biology major?

Bill
Psalmopoeus and Taphinauchenius are the only two NW genera without urticating hairs.

As for the Poecilotheria-Psalmopoeus connection, I don't know what the link is myself, either. It may be little nitpicky things (like the genitalia suggested above) or it's also possible someone did some clade analysis on the DNA. When I get some time, maybe I'll go poking around in the bio abstracts, if it was a DNA analysis, it should be cited somewhere. If it was genitalia, it's probably buried in a taxonomy publication who knows where.
 

Martin H.

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Originally posted by Code Monkey

Psalmopoeus and Taphinauchenius are the only two NW genera without urticating hairs.
To my knowledge there are some more NW species without urticating hairs, for example the genus Holothele. But I am not soooo familiar with NWorlders! =;-)


As for the Poecilotheria-Psalmopoeus connection, I don't know what the link is myself, either. It may be little nitpicky things (like the genitalia suggested above) or it's also possible someone did some clade analysis on the DNA. When I get some time, maybe I'll go poking around in the bio abstracts, if it was a DNA analysis, it should be cited somewhere. If it was genitalia, it's probably buried in a taxonomy publication who knows where.
check this:
  • Raven, R. (1985): The Spider infraorder Mygalomorphae (Araneae): Cladistics and Systematics. Bull. Amer. Mus. Nat. Hist. 183, (1): 1 - 180.

all the best,
Martin
 

Martin H.

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I have found another paper:
  • Samuel D. Marshall, Robert J. Raven & Walter R. Hoeh: A TEST OF ALTERNATIVE PHYLOGENETIC HYPOTHESES FOR THE INTERRELATIONSHIP OF THERAPHOSID SUBFAMILIES USING A CLADISTIC ANALYSIS OF MORPHOLOGICAL TRAITS.
"... While certain clades have remained fairly stable, the placement of some genera has been problematic (e.g., Ephebopus, Psalmopoeus, Hapalopus). To test alternative hypotheses of theraphosid interrelationships, we obtained a morphological data matrix containing 33 characters representing both morphological and behavioral features. [...] We found no support for the placement of Psalmopoeus in the Aviculariinae as proposed by Schmidt (1993), but instead support its placement in the Selenocosmiinae as proposed by Raven (1985). ..."

BTW, they used PAUP for this analysis.

all the best,
Martin

PS.: I can eMail you the whole abstract/summary if you are interested in.
 

Code Monkey

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Originally posted by Martin H.
To my knowledge there are some more NW species without urticating hairs, for example the genus Holothele. But I am not soooo familiar with NWorlders! =;-)
Oops, my bad. I did some more poking and found that Crytopholis also apparently lack them - guess that would have been another diagnostic for the person trying to decided if they had a C. porporicae the other day: rub that butt and see what happens to you ;) I always the Taph and Psalm genera mentioned when lacking urticating hairs I somehow decided they were the only ones :8o

check this:
  • Raven, R. (1985): The Spider infraorder Mygalomorphae (Araneae): Cladistics and Systematics. Bull. Amer. Mus. Nat. Hist. 183, (1): 1 - 180.
Thankyou very much, so it was a clade analysis, that gives it a bit more oomph in the accuracy department.
 

MrDeranged

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Originally posted by Code Monkey
Thankyou very much, so it was a clade analysis, that gives it a bit more oomph in the accuracy department.
Hey Guys,

How about posting that in English for those of us who didn't get past Bio 101? :D

Scott
 

Code Monkey

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Originally posted by mrderanged
Hey Guys,

How about posting that in English for those of us who didn't get past Bio 101? :D

Scott
In English: It's a bit like DNA fingerprinting, only more thorough. You look at the a large number of the exact same portions of the DNA from a number of organisms of each species, for example, one of the things you might look at is the gene for some highly conserved protein kinase that is found in yeast to blue whales. From how different (or how similar) those portions are from one another you can statistically determine how closely related the different species are. It's basically the future of taxonomy because it's easily quantified and not subject to what arbitrary characters a taxonomist focuses on.

The idea is that since DNA sequences only change through random mutation, the more differences that accumulate, the greater the time span since the two species shared a common ancestor. By looking at enough gene sequences you can create a clade tree which shows the branch points as the different genera and species evolved from common ancestors.

A simple example for the tongueless frogs: http://www.utexas.edu/courses/zoo453/tol/salientia/pipidae/pipidae.html
 
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Martin H.

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Hello Code Monkey and all,

maybe I don't understand your posting correct, but I think you mix some things up!
I have never heard DNA in the combination of a cladistic or phologenetic analysis. Normally you use morphological attributes/characters and appraise them to make a phylogenetic tree for the relations of the different species. Probably you also can do DNA analysis, but I don't think that Raven or Marshall et al. have done this.

I have not the time for an exact explanation nor my English is good enough for this. But there are a lot of documents in the WWW about the cladisitic. For example these two:
  • Lipscomb, D. (1998): Basics of Cladistic Analysis
    >>download here<<
  • E.O. Wiley, D. Siegel-Causey, D.R. Brooks, and V.A. Funk (2000): The Compleat Cladist: A Primer of Phylogenetic Procedures.
    >>click me<<


all the best,
Martin
 

Code Monkey

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You can do it with characters, and that's of course how classic analysis was performed (and maybe I jumped the gun on assuming how they did the Psalmopoeus, Poecilotheria analysis without actually reading the paper), but it is also very common to do it with genetics or biochemical methods anymore. In fact I would estimate that most *current* work is with genetic or biochemical based clade analysis because character typing has been pushed about as far as it will go for unequivocably answering most of these questions.

For instance, Triops longicaudatus is found throughought much of the world based morphological based analysis. Recent genetic clade analysis has revealed multiple subspecies that have been separated for 15 million years, 20 millions years, even longer but are morphologically identical to an examination. This is also how the issue of whether L. packardi was actually a distinctly separate species from L. apus versus a subspecies was put to rest. I don't know what they're doing with tarantulas, but biochemical and genetic clade analysis is the rule anymore as far as I know (at least in the papers I've looked at regarding the subject).

At any rate, I was misleading in my above answer. When *I* hear cladistic analysis I think DNA or protein sequences, but I did leave out a few hundred years of classical cladistic analysis :8o

Same idea, measure multiple characters among similar species such as femur length, number of toes, whatever, and apply the same sort of statistical analysis to get a picture of when they diverged evolutionarily.
 
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Martin H.

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Hi Code Monkey,

thanks for the enlightenment!

...from tarantulas I only knew the "classical" characters analysis. DNA screening is not cheap, wondering if anybody would spend money to do this with "valueless" tarantulas!?

all the best,
Martin
 

Code Monkey

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Originally posted by Martin H.
DNA screening is not cheap, wondering if anybody would spend money to do this with "valueless" tarantulas!?
It's not *that*expensive, but it's probably outside the budget of your average taxonomist unless he already happens to have full blown lab laying around somewhere. From my understanding, a lot of this stuff gets done by grad students in molecular biology departments. I had a friend who did his thesis on doing such an analysis between manatees and elephants. The L. packardi/apus was another such thesis. If anyone here is thinking about a masters in molecular biology and isn't too squeamish to puree a number of chilled tarantulas, there's easily a degree in some of this stuff.
 
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