tag:blogger.com,1999:blog-8397350206066419382.post7983946157091650088..comments2024-02-04T04:35:57.404-06:00Comments on Tyrannosauroidea central: Introducing Daspletosaurus horneri, the Two Medicine Tyrannosaurine: AnagenesisThomas Carrhttp://www.blogger.com/profile/16222089653141920186noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-8397350206066419382.post-72817704439630373012017-10-28T03:46:17.798-05:002017-10-28T03:46:17.798-05:00Keep up the good work , I read few posts on this...Keep up the good work , I read few posts on this web site and I conceive that your blog is very interesting and has sets of fantastic information.<br /><a href="https://plus.google.com/102696755549001418336" rel="nofollow">dutasteride buy</a><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-4715442814087707862017-04-03T11:16:48.573-05:002017-04-03T11:16:48.573-05:00Hi Dave!
Many thanks for your helpful comments - ...Hi Dave!<br /><br />Many thanks for your helpful comments - I will follow up on the literature that you've mentioned. I do realize that poor sampling can artifactually place an ancestor after its descendant, but, as you know, in the post I was describing the ideal case. I think it is very encouraging that yourself and Andrea are applying statistical techniques to the question of anagenesis, and it is something I will follow with great interest!<br /><br />Many thanks for the slide show - I have been through it once already! I emphasize that the hypothesis we've presented is testable through continued sampling of the Oldman, Dinosaur Park, and Two Medicine Formations.<br /><br />Sincerely,<br />ThomasThomas Carrhttps://www.blogger.com/profile/16222089653141920186noreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-38790425250868780982017-04-03T11:01:20.597-05:002017-04-03T11:01:20.597-05:00Hi Thomas,
First, I'd like to say that I'...Hi Thomas,<br /><br />First, I'd like to say that I'm very excited to see work on the question of anagenesis and cladogenesis (which might be budding or bifurcating). There's hasn't been enough work in that area, and its a question I've been very interested in! These are definitely questions that we need to address, as paleontologists, as they are central to the question of what morphospecies are, and the ecological factors behind morphological change!<br /><br />Perhaps you are already aware of it, but if not, I think you might be quite interested in reading Pete Wagner and Doug Erwin's 1995 book chapter, which tries to measure the extent of anagenesis versus cladogenesis in several invertebrate and foraminifera datasets. I'd be happy send a PDF by email if you don't have access.<br /><br />Now, that said, I'm a little cautious about conclusions that a particular lineage is anagenetic or not. The issue for me is that sequences that appear to be anagenetic could be cladogenesis (either budding or bifurcating, sensu Foote, 1996), but its impossible for lineages that show overlap (and thus reflect cladogenesis) to be an anagenetic ancestor-descendant pair. (Note though that Ezard et al. 2012 don't agree with this, as they think both morphotypes may exist for a short interval.) Part of my issue here is that its very easy for taxon durations to be extremely truncated in poorly sampled fossil records, and thus to lose intervals of overlap that would rule out anagenesis. And, contrary to what you say, in a very poorly sampled fossil record, there would likely even be instances where the apparent temporal order of appearance of an ancestor and descendant could be reversed. Its hardly unreasonable, and statistically speaking, nearly guaranteed to happen at least a few times within large, poorly sampled clades.<br /><br />I think methods that take into account the frequency of sampling, like the tip-dating methods which Andrea mentions wanting to apply, is an important next step for testing the anagenesis hypothesis. That class of methods allows us to put support on the extent that any particular fossil is directly ancestral to another observed lineage. <br /><br />I gave a recent talk on some of these newer approaches, and the inference of ancestors, which you can view here: https://www.slideshare.net/dwbapst/gsa-2016-talk-inferring-ancestordescendant-relationships-in-the-fossil-record-with-statistics<br /><br />Despite my comments, I want to reiterate that I found your work extremely intriguing and I look forward to seeing more from you and your colleagues!<br /><br />Cheers,<br />-Dave Bapstdwbapsthttps://www.blogger.com/profile/17606476387441191531noreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-8305786844020414642017-04-02T17:57:05.297-05:002017-04-02T17:57:05.297-05:00mbs, you are too kind - thank you for your positiv...mbs, you are too kind - thank you for your positive comment!Thomas Carrhttps://www.blogger.com/profile/16222089653141920186noreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-40028606911577981872017-04-02T17:52:08.955-05:002017-04-02T17:52:08.955-05:00I truly admire your work Carr! Keep it up !I truly admire your work Carr! Keep it up !mbshttps://www.blogger.com/profile/17671386797371915582noreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-24744500776858784592017-04-02T08:21:24.830-05:002017-04-02T08:21:24.830-05:00Thank you for alerting me to the problem - I just ...Thank you for alerting me to the problem - I just sent you the original excel files, and a NEXUS is on its way.Thomas Carrhttps://www.blogger.com/profile/16222089653141920186noreply@blogger.comtag:blogger.com,1999:blog-8397350206066419382.post-58272948114024203662017-04-02T06:00:07.488-05:002017-04-02T06:00:07.488-05:00Congrats for the description of this new tyrannosa...Congrats for the description of this new tyrannosaurid, Thomas.<br />I'd like to replicate the phylogenetic analysis using the Bayesian tip-dating methods I have been testing, which allow to quantitatively estimate the frequency of anagenesis in fossil evolution.<br />Unfortunately, I have tried to assemble the data matrix from the suppl. file in the Scientific Reports paper, but the matrix seems damaged (e.g., Compsognathus and Yutyrannus are scored for less characters than the list reported, and so on).<br />Please, could you send me a nexus file version of the matrix to cauand at gmail dot com?<br />Thanks.Andrea Cauhttps://www.blogger.com/profile/10855060597677361866noreply@blogger.com