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Natural Science Forum / Biology / Paleontology / February 2005Question
Has been digs done in Antarctic that given us a clearer picture of the fauna that inhabited Antarctica before it totally froze over. I heard about the diggings done on Seymour Island. > Has been digs done in Antarctic that given us a clearer picture of the > fauna that inhabited Antarctica before it totally froze over. I heard > about the diggings done on Seymour Island. Yes. For example, see this: http://www.palaeontologia.pan.pl/pp60.htm Cheers, Dawid. > Has been digs done in Antarctic that given us a clearer picture of the > fauna that inhabited Antarctica before it totally froze over. I heard > about the diggings done on Seymour Island. Yes and no. See Richard Dawkins' "The Ancestor's Tale". There are 10 index entries for "Antarctica", but a valid, brief summary might be from Page 238, which states: "Plant fossils tell us that Cretaceous Antactica was sub-tropical, lush with vegitation, and a fine place for animals to live. The dearth of fossils that have actually been found cannot reflect a corresponding dearth of animals; a rich vegetation like that must have supported an equally rich fauna. As I've already mentioned, among the few fossil animals the have been found are large ratites..." Regards, Brett. > > Has been digs done in Antarctic that given us a clearer picture of the > > fauna that inhabited Antarctica before it totally froze over. I heard [quoted text clipped - 13 lines] > > Regards, Brett. (Although Dawkins did not typo "vegetation" half the time, nor have "the" for "that", as I did in my earlier post). >>Has been digs done in Antarctic that given us a clearer picture of the >>fauna that inhabited Antarctica before it totally froze over. I heard [quoted text clipped - 11 lines] > mentioned, among the few fossil animals the have been > found are large ratites..." Large ratites? Cretaceous ratites? Does Dawkins give a reference for this? > Regards, Brett. > >>Has been digs done in Antarctic that given us a clearer picture > >>of the fauna that inhabited Antarctica before it totally froze over. [quoted text clipped - 13 lines] > > Large ratites? Cretaceous ratites? Does Dawkins give a reference for this? Perhaps I should have completed the paragraph for context: "As I've already mentioned, among the few fossil animals the have been found are large ratites, some as large as moas, and it seems likely that these birds were abundant in Cretaceous Antactica. If not necessarily Ratite Grand Central Station, Antarctica provided a clement and ratite-friendly land bridge linking Africa and South America on one side of the world to Australia and New Zealand on the other, and India/Madagascar too." And while a reference might be found elsewhere (he lists 327 in the biblio.), I don't see one where I would hope to. Regards, Brett. >>>>Has been digs done in Antarctic that given us a clearer picture >>>>of the fauna that inhabited Antarctica before it totally froze over. [quoted text clipped - 29 lines] > And while a reference might be found elsewhere (he lists 327 in the > biblio.), I don't see one where I would hope to. Regards, Brett. OK. For the record, I have no idea what Dawkins is talking about here. As far as I know, there are no Cretaceous records of Paleognathae at all. Some few have been suggested, but subsequent analyses have rejected all of them, and none of them are from Antarctica anyway. And as far as I know, there are no known paleognath fossils from Antarctica, of any age. I could easily have missed some, though, and that's why I'm asking. I note he says "I've already mentioned". Can you find his first mention, and is there a reference there? > >>>>Has been digs done in Antarctic that given us a clearer picture > >>>>of the fauna that inhabited Antarctica before it totally froze over. [quoted text clipped - 17 lines] > > > > "As I've already > > mentioned, among the few fossil animals the have been > > found are large ratites, some as large as moas, and it [quoted text clipped - 17 lines] > I note he says "I've already mentioned". Can you find his first mention, > and is there a reference there? Not that I find, but here's what I think is the first instance, in case you're interested, from Page 237: Ratite fossils have even been found in Antarctica, which we know from plant fossils to have been covered with warm, subtropical forest at the time. Ancestral ratites wandered freely over the whole continent of Gondwana with no inkling that their homeland was destined to be broken up into chunks separated by thousand of miles of ocean. >>>>>>Has been digs done in Antarctic that given us a clearer picture >>>>>>of the fauna that inhabited Antarctica before it totally froze over. [quoted text clipped - 54 lines] > Gondwana with no inkling that their homeland was destined to be > broken up into chunks separated by thousand of miles of ocean. No reference, eh? I can be fairly certain that there were no Cretaceous ratite fossils when Dawkins wrote, or Sylvia Hope would have covered them in her review. It remains possible that there are some recently discovered early Tertiary ratites from Antarctica that I don't know about. Certainly the bird fauna of Antarctica before it froze over must have been similar to that of the rest of Gondwana, and it would be great to have more material. Of course that's true almost as much for the rest of Gondwana, and almost as much as that for even North America and Europe. It seems likely in this case that Dawkins was mistaken, but a possible source of the assertion of 'Cretaceous Antarctic ratites' is the probably Eocene, probably dromornithid foot impression from the Redbank Plains Formation near Brisbane, Australia (Vickers-Rich & Molnar 1996): 1. Australia and Antarctica were connected by land up to about 45 million years ago. 2. Australian early Eocene vertebrates (e.g. the Tingamarra Fauna, which has similar turtles and crocs to Redbank Plains) have many similarities to Late Cretaceous and Paleocene faunas from Patagonia, and these shared elements probably also occupied Antarctica during the same time interval. But, contrary to what has been believed for over a century, the extinct Dromornithidae were not 'ratites' except in the descriptive sense of being big flightless birds. They're actually big flightless Anseriformes, possibly the sister group of Anseranas (Australian Magpie Goose). Almost everything known about Droms is in an excellent book (2004) by Peter Murray and Pat Vickers-Rich (http://www.indiana.edu/~iupress/books/0-253-34282-1.shtml). There are several index entries for 'Antarctica', more for 'ratites', and no page mentioning both. Casuariid ratites were rather rare as fossils until the Pleistocene, and the oldest known are early Miocene. It's surprising to catch Dawkins out in an error. Perhaps this can be attributed to the fact that a Gondwana-spanning flightless ratite ancestor is predicted by most models of evolution in this group. I think it might be better (though less parsimonious) to adopt the working hypothesis that the African, South American, Austraopapuan and New Zealand palaeognath groups lost flight independently: at least this hypothesis could be falsified by finding some big old flightless ancestor in Antarctica or somewhere else, and we would be less tempted to slip in the assumption that one had already turned up. John > It seems likely in this case that Dawkins was mistaken, but a possible > source of the assertion of 'Cretaceous Antarctic ratites' is the [quoted text clipped - 16 lines] > (2004) by Peter Murray and Pat Vickers-Rich > (http://www.indiana.edu/~iupress/books/0-253-34282-1.shtml). Thanks. I'll have to look that up. A sister group for Anseranas would be nice. > There are > several index entries for 'Antarctica', more for 'ratites', and no page [quoted text clipped - 4 lines] > attributed to the fact that a Gondwana-spanning flightless ratite > ancestor is predicted by most models of evolution in this group. Not mine, though. > I > think it might be better (though less parsimonious) to adopt the [quoted text clipped - 3 lines] > ancestor in Antarctica or somewhere else, and we would be less tempted > to slip in the assumption that one had already turned up. It could also be supported by discovering that tinamous were the sister group of some particular living ratite, rather than all of them. [snip] > But, contrary to what has been believed for over a century, the extinct > Dromornithidae were not 'ratites' except in the descriptive sense of [quoted text clipped - 3 lines] > (2004) by Peter Murray and Pat Vickers-Rich > (http://www.indiana.edu/~iupress/books/0-253-34282-1.shtml). Whoa. $75. Perhaps I'll just ask you a question or two. Is there a rigorous phylogenetic analysis of Anseriformes, with complete character matrix, in the book, or do they just reach their phylogenetic conclusions in a touchy-feely way? If the former, do they incorporate presbyornithids and/or gastornithids into the analysis? > [snip] > [quoted text clipped - 13 lines] > If the former, do they incorporate presbyornithids and/or gastornithids > into the analysis? In Ch. 6 of Murray & Vickers-Rich (pp. 149-162) they score Dromornithidae (as a single composite terminal taxon) for the character sets of Ericson (1997), Livezey (1997) and Andors (1992) whose data matrices they give in full; in these 3 analyses with different sets of ingroup taxa the droms are placed as sister group to: (Anseranas(Presbyornithidae,Anatidae)); (Presbyornithidae,Anatidae); and (Anhimidae(Anseranas,Anatidae)) respectively. Ch.7 (163-169) is a discussion of the Shorebird Origin vs. Galliform Origin models for Anseriformes, including several cladograms in which Dromornithidae is depicted as sister group to Anhimidae. Basically, they see relationships as unresolved at a (Dromornithidae, Anhimidae, Anseranatidae, (Presbyornithidae, Anatidae)) polytomy after a split between Anseriformes and Diatrymatidae. The authors point out that relationships within Dromornithidae and among other birds would be better resolved when more 'basal anseriform' fossils have turned up (they don't accept that Presbyornis fits this role as proposed by Olson & Feduccia, and Diatryma is too specialised). I would add that an equally or more useful thing would be better material of the most basal and plesiomorphic (& smallest) dromornithid, which is a thing called Barawertornis tedfordi from Riversleigh, described by PVR from a few scraps of limb bones in 1979. A lot more Bt material is in the process of being described by W. Boles (Australian Museum) which is one reason why M&VR leave the phylogenetic analysis unconcluded. Walter's mainly studying limb bones, while I'm getting lots more pieces, including bits of braincase and bill, out of one of the older (late Oligocene) Riversleigh deposits. A bit more acid-processing and some jigsaw work, and Barawertornis will be less of a mystery. Cheers, John >>[snip] >> [quoted text clipped - 39 lines] > (Anseranas(Presbyornithidae,Anatidae)); (Presbyornithidae,Anatidae); > and (Anhimidae(Anseranas,Anatidae)) respectively. Dang. Looks as if I have to buy the book. But I thought you said they were sister group of Anseranas? None of these topologies does that. As far as living groups are conserned, they're either sister to Anatoidea (Aseranas + Anatidae) or Anseriformes. > Ch.7 (163-169) is a discussion of the Shorebird Origin vs. Galliform > Origin models for Anseriformes, including several cladograms in which > Dromornithidae is depicted as sister group to Anhimidae. Presumably by "galliform origin" you mean the existence of Galloanserae, not a claim that anseriforms are nested within Galliformes. And I hope they conclude that the evidence is decisive on Galloanserae. I would otherwise be very annoyed. > Basically, they see relationships as unresolved at a (Dromornithidae, > Anhimidae, Anseranatidae, (Presbyornithidae, Anatidae)) polytomy after > a split between Anseriformes and Diatrymatidae. As I recall, Andors was unable to determine robustly if diatrymids/gastornithids were sister to Anseriformes or to Galloanserae. Do the new taxa make that better, at least? > The authors point out that relationships within Dromornithidae and > among other birds would be better resolved when more 'basal anseriform' [quoted text clipped - 11 lines] > acid-processing and some jigsaw work, and Barawertornis will be less of > a mystery. Cheers, I'm looking forward to it. Obviously we need more basal species in all the clades, and better material for those we have. Missing data can be nasty. Hey, at least we know the basal topology among living species. Hope that counts for something. >It seems likely in this case that Dawkins was mistaken, but a possible >source of the assertion of 'Cretaceous Antarctic ratites' is the [quoted text clipped - 31 lines] > >John Has anyone considered e-mailing Dawkins and asking him for a reference. Seems a simple enough thing to do. --RC "Sometimes history doesn't repeat itself. It just yells 'can't you remember anything I've told you?' and lets fly with a club. -- John W. Cambell Jr. >>It seems likely in this case that Dawkins was mistaken, but a possible >>source of the assertion of 'Cretaceous Antarctic ratites' is the [quoted text clipped - 35 lines] > reference. > Seems a simple enough thing to do. OK. I just did. I'll let you know what happens. > > Has anyone considered e-mailing Dawkins and asking him for a > > reference. > > Seems a simple enough thing to do. > > OK. I just did. I'll let you know what happens. Hi, Just keeping track of this conversation, but it took me a while to dig up the reference. The ratite reference found by Sam Turvey to justify the statement about Antarctic ratites is: Tambussi, C.P. et al. 1994. Ratite bird from the Paleogene La Meseta Formation, Seymour Island, Antarctica. Pol. Polar Res. 15: 15020-15026. Apologies for not putting it in the references, but as I'm sure you can appreciate, we didn't have enough space to include references justifying every statement in the book! Best wishes Yan Wong >>>Has anyone considered e-mailing Dawkins and asking him for a >>>reference. [quoted text clipped - 14 lines] > appreciate, we didn't have enough space to include references > justifying every statement in the book! Sure. But that's not a Cretaceous ratite. (Assuming it's a ratite at all, since a supposed Cretaceous presbyornithid described by the same authors has been trashed in the literature.) We still have no evidence that I know of for the existence of ratites anywhere during the Cretaceous. We have good indirect evidence for the existence of paleognaths during the Cretaceous, but none for ratites. John Harshman <jharshman.diespamdie@pacbell.net> wrote in message news: > Sure. But that's not a Cretaceous ratite. Indeed. The phrasing in that paragraph is rather ambiguous (some might even say misleading). We may be able to correct it in future print runs, and in the paperback edition (a few other factual corrections have gone in too). > We still have no evidence > that I know of for the existence of ratites anywhere during the > Cretaceous. We have good indirect evidence for the existence of > paleognaths during the Cretaceous, but none for ratites. Yes, I would agree with this. But it certainly wouldn't surprise me if a Cretaceous ratite were found, especially given the current paucity of fossils from Cretaceous Antarctica. But this isn't my specialism, so I'll stop there. Yan > John Harshman <jharshman.diespamdie@pacbell.net> wrote in message news: > [quoted text clipped - 14 lines] > of fossils from Cretaceous Antarctica. But this isn't my specialism, > so I'll stop there. No, it wouldn't surprise me if Cretaceious ratites were found, but it also wouldn't surprise me if they were not found. We have very little to base expectations on, one way or the other. >> > Has anyone considered e-mailing Dawkins and asking him for a >> > reference. [quoted text clipped - 18 lines] > >Yan Wong Thanks. Great book BTW. Got it for my father for Christmas and he loaned it back to me so I could read it. --RC Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad -- Suzie B rcook5@TAKEOUTmindspring.com wrote > Great book BTW. > Got it for my father for Christmas and he loaned it back to me so I > could read it. Thanks. I'm glad you enjoyed it. Yan > > Great book BTW. > > Got it for my father for Christmas and he loaned it back to me so I [quoted text clipped - 3 lines] > > Yan I also enjoyed the book very much, Yan - thanks. But a question has arisen over at sci.bio.evolution as to the relative absence of viruses in the book (e.g. no explicit Rendezvous, although I note you do have an index entry). Where viruses would be on any of the trees, say on Page 436-7 or 461, or are they outside of these? Regards, Brett Aubrey. Hah, I noticed that thread, and was thinking of penning a reply. As far as I know, the origin of viruses is obscure (but someone may correct me on this one). The most likely hypothesis to me is that they are transposable elements which have gained the capability of horizontal as well as vertical transmission. Certainly the gypsy element in Drosphila can also be passed on through food, so the distinction between viruses and TEs is not a clear cut one. If that's true, then different classes of viruses may be related to humans to differing degrees, depending on the organism from which they originally escaped. Since viral DNA or RNA mutates so quickly, it may be impossible to deduce exactly which branch of the tree different viral classes belong to. If anyone knows any decent references on the phylogeny and origin of viruses, I'd be interested to know. Cheers Yan I have found also this article concerning polar mesozoic gastropods: Kaim, A. , Beisel, A.L., Kurushin, N.I. 2004. Mesozoic gastropods from Siberia and Timan (Russia). Part 1: Vetigastropoda and Caenogastropoda (exclusive of Neogastropoda). Polish Polar Research 24, 3-4, 241-266. http://www.paleo.pan.pl/people/Kaim/Publications/kaim-ppr-2004.pdf Cheers, Dawid. Found also one concerning antarctic oligocene scleractinians: Stolarski, J., Taviani, M. 2002. Oligocene scleractinian corals from CRP-3 Drillhole, Victoria Land Basin, Antarctica. Terra Antarctica (2001) 8: 435-438. http://www.paleo.pan.pl/people/Stolarski/Publications/TA2002-Flabellum.pdf Cheers, Dawid. Oh, I forgot. Try browsing: Polish Polar Pesearch http://www.polish.polar.pan.pl/ You will find lots of paleontological papers concerning antarctic regions. Cheers, Dawid. As for Arctica's flightless birds (though not ratites) record, I recommend: Myrcha, A., Jadwiszczak, P., Tambussi, C. P., Noriega, J. I., Gazdzicki, A., Tatur, A., Del Valle, R. A. 2002. Taxonomic revision of Eocene Antarctic penguins based on tarsometatarsal morphology. Polish Polar Research 23 (1): 5-46. http://www.polish.polar.pan.pl/ppr23/ppr23-005.pdf Cheers, Dawid. As for Arctica's flightless birds (though not ratites) record, I recommend: Myrcha, A., Jadwiszczak, P., Tambussi, C. P., Noriega, J. I., Gazdzicki, A., Tatur, A., Del Valle, R. A. 2002. Taxonomic revision of Eocene Antarctic penguins based on tarsometatarsal morphology. Polish Polar Research 23 (1): 5-46. http://www.polish.polar.pan.pl/ppr23/ppr23-005.pdf Cheers, Dawid. |
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