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Marsupial tapirs, diprotodontids, wombats and others: the vombatiform radiation, part II

The views expressed are those of the author and are not necessarily those of Scientific American.


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Palorchestids (= 'marsupial tapirs'), as illustrated by Frank Knight for the 1985 book Kadimakara: Extinct Vertebrates of Australia.

ResearchBlogging.org

Time to finish up on those fantastic vombatiforms. Be sure to read part I first. In part I, we looked at koalas and marsupial lions, both of which seem to be outside Vombatoidea, the vombatiform clade that includes wombats and the superficially wombat-like, mostly terrestrial diprotodontids and kin. This current article surveys vombatoid diversity. Yes, wombats and such diprotodontids as Diprotodon are fairly familiar – but what about wynyardiids, maradids, ilariids?

Among the most peculiar vombatiforms and most peculiar of diprotodontians are the wholly extinct palorchestids, sometimes termed marsupial tapirs or tree-pushers. Seven species are known in two genera (Miocene-to-Pleistocene Palorchestes and Oligocene-Miocene Propalorchestes). They seem to be the sister-group of Diprotodontidae, with the palorchestid + diprotodontid clade being known as Diprotodontoidea (Archer et al. 1999) [see cladogram at bottom]. Palorchestes was originally interpreted (by Richard Owen in 1874) as a giant kangaroo and various reconstructions of its skull and life appearance perpetuated this idea until as recently as the 1950s.

Another palorchestid reconstruction, this time by Peter Schouten. Sorry about the small size.

A narrow and retracted nasal region suggest the presence of a trunk, a reasonably large tail is present (note that this isn’t shown in Knight’s reconstruction), the forelimbs were heavily muscled with a partially immobile elbow joint and near-solid ulna*, and the claws on both the hands and feet are large and laterally compressed. Palorchestes has thus been described as “a composite animal with tapir, chalicothere, pantodont, and slothlike features” (Murray 1984, p. 608) and as surely “enough to have inspired the legend of the bunyip – or at least a few nightmares among Australia’s first Aboriginal inhabitants” (Flannery & Archer 1985, p. 236). Knuckle-walking and digital hyperextension (where the claws are retracted like those of cats) have been suggested for palorchestids, as has the idea that they were koala-like or sloth-like climbers.

* The medullary cavity is strongly reduced and absent for much of the bone’s length.

The Miocene vombatiforms Ngapakaldia and Pitikantia have been regarded as palorchestids by some authors. Ngapakaldia at least was apparently superficially diprotodontid-like, but with hand and wrist features suggestive of a climbing ability. Some carbon-dated Palorchestes specimens have been dated to c. 36,000 years old and rock art supposed to depict this animal has been reported. One of those paintings is shown here (borrowed from here on History of Geology) – I’m unable to make much sense of it and don’t exactly find it convincing.

Apparently, there's a quadrupedal animal with a big nose in here somewhere.

Ilariids, wynyardiids, maradids

Among the most poorly known of vombatiforms are the Late Oligocene ilariids, known only for the two Ilaria species (I. illumidens and I. lawsoni) and Kuterintja ngama. Koobor (sometimes suggested to be a koala) has also been regarded as an ilariid by some authors. Ilariids are only known from teeth and fragmentary jaws, so there isn’t a great deal of interesting stuff to say about them. They possessed horizonally projecting, subcylindrical lower incisors (as is typical for diprotodontians) and especially tall-cusped premolars and molars suited for herbivory. Their molars were selenodont and hence koala-like. Munson (1992) found ilariids to be the sister-group to a wynyardiid + diprotodontoid clade, but they’ve also been hypothesised to be particularly close to wombats at times (Weisbecker & Archer 2008).

Namilamadeta skull, from Archer et al. (1991).

Another group generally included within Vombatoidea is the wholly extinct Wynyardiidae, currently known from seven species in three genera (Wynyardia, Muramura and Namilamadeta). The first wynyardiid to be recognised – Early Miocene Wynyardia bassiana from Tasmania – was discovered early on in the history of Australian palaeomammalogical research: some time round about 1860. It actually wasn’t named or described until 1901, partly because it was assumed to be the skeleton of a modern species, not a fossil one (Aplin & Rich 1985). For a long time, it was the only pre-Pleistocene Australian marsupial fossil known to science. However, numerous Late Oligocene and additional Early Miocene wynyardiid fossils have been discovered since the 1970s, many of them at Riversleigh. Wynyardiids are postcranially similar to primitive wombats, and some experts have reconstructed them as wombat-like, terrestrial herbivores. Others, however, have suggested that Wynyardia at least was a generalist arboreal herbivore (Macphail 1996). Wynyardia was perhaps similar in size to a large possum while forms like Namilamadeta were badger- or wombat-sized.

A slender, gracile vombatiform dentary from the Late Oligocene of Queensland was named as the new species Marada arcanum by Black (2007) and suggested to be distinctive enough to warrant the creation of a new ‘family’, Maradidae [holotype dentary shown here, from Black (2007)]. Very little is known of Marada, but its combination of features led Black (2007) to suggest that it might be closely related to wynyardiids or diprotodontoids. Weakly developed lophodonty on its low-crowned teeth suggest that it was a browser. The dentary is about 15 cm long, so it was a reasonably large animal.

Diprotodontines and zygomaturines

Diprotodontids (this term not to be confused with Diprotodontia) are best known for the gigantic Pleistocene form Diprotodon, often imagined to look something like a rhino-sized wombat (always always always [well, virtually always] shown with shaggy brown hair). Diprotodon was indeed very large with a mass of perhaps 2700 kg or so: it was the largest marsupial that ever lived. Peculiar, elevated crests around the external nostrils suggest that it had a highly specialised nose. Some people have illustrated it with a short, tapir-like trunk while others think that it had an enormous, koala-like rhinarium. Spatulate upper incisors and long, chisel-like lower ones might be browsing adaptations for a diet of tough, spiky plants. Its presence across continental Australia shows that it was a habitat generalist, able to make a living in woodlands, semi-arid plains and other regions (Price 2008).

Diprotodon skeleton, photo by John O'Neill, from wikipedia.

Like most diprotodontids, Diprotodon has proportionally small hands and feet and highly inflexible wrists and ankles. Massive, sometimes extensively fused ankle bones took much of the animal’s weight (within diprotodontids as a whole, this is most extensively expressed in Euowenia from the Pliocene), some of the hand bones were also peculiarly enlarged and suited for weight-bearing, and the stout, columnar limbs were clearly specialised for graviportality. At least some diprotodontids might have been able to stand bipedally when foraging (Camens & Wells 2010).

Of course, Diprotodon is merely one of several closely related forms, the oldest of which are from the Late Oligocene. Others include Pitikantia, Bematherium, Pyramois, Meniscolophus, Euowenia and Euryzygoma. These are all diprotodontine diprotodontids. Some (like Euryzygoma) possess flaring bony cheek processes and enormous cranial sinuses. Sexual dimorphism is apparently present in Neohelos and Diprotodon. In Diprotodon, what appear to be two sexes were long regarded as two species (D. optatum is the big one; D. minor is the smaller one). It seems that this animal lived in small, gender-segregated herds (Price 2008).

Zygomaturus: skeletal reconstruction by Peter Murray, life restoration by Nobu Tamura.

Diprotodontidae also includes the more diverse zygomaturine radiation, the members of which include Silvabestius, Alkwertatherium, Nimbadon, Kolopsoides, Plaisiodon, Kolopsis and Kukaodonta. These have mostly been interpreted as forest-dwelling, terrestrial herbivores but the presence of flexible, possum-like hands and curved hand claws in sheep-sized Nimbadon suggest that this form at least was capable of climbing (Weisbecker & Archer 2008). The best known zygomaturine – Zygomaturus – has a raised, flaring nasal region where two roughened lumps project above the nostrils. Both might have supported keratinised pads or horns, and indeed Zygomaturus has often been illustrated with two short horns on its snout tip. Dwarf zygomaturines known from the Pleistocene of New Guinea (Hulitherium and Maokopia) have been interpreted both as relicts from an old (Miocene) invasion and as more recently evolved, highly specialised taxa.

Where the wombats are

Photo by Stygiangloom, from wikipedia.

And, finally, we come to the wombats (or Vombatidae, sometimes Phascolomyidae in older literature), represented today by the Common or Coarse-nosed wombat Vombatus ursinus and the two or three endangered hairy-nosed wombats (Lasiorhinus) [L. latifrons shown here]. Despite appearances, wombats aren’t closely related to koalas (though some authors have suggested that they are: a subject I’ll cover in another article). All are stout-bodied, burrow-dwelling herbivores with forelimb anatomy indicative of a scratch-digging lifestyle. They can weigh as much as 38 kg and possess a superficially rodent-like, root-less dentition (they give nasty bites) and small cheek pouches.

Wombat droppings are square and also among the driest reported for any mammal. Wombats mate with the female lying on her side while the male crouches over her in normal quadrupedal pose (Taylor 1993). Wombat burrows can be as long as 30 m and, in the Southern hairy-nosed wombat L. latifrons, large warrens are constructed and remain in use for generations. As many as ten animals share the same warren, but they seem to interact infrequently and to feed solitarily (Johnson 2001).

The oldest wombat is currently Rhizophascolonus from the Early Miocene. Early wombats have relatively short-crowned teeth with closed roots while later ones have tall-crowned teeth with open, continuously growing roots (and there are intermediate ones, with tall crowns but closed roots). These teeth allowed wombats to exploit grasses, and (along with macropods) they’re among the few diprotodontian lineages that diversified in the arid grassland habitats that spread across Australia during the Pliocene and Pleistocene.

Phascolonus skeletal reconstruction, by Peter Murray.

Diprotodon and its kin were not giant wombats, but truly giant members of this group did evolve. Both Phascolonus (with spatulate incisors) and Ramsayia (with narrow incisors) stood about 70 cm tall at the shoulder; the former has an estimated mass of 250 kg. Intermediate-sized (e.g., Phascolomys) and small (Vombatus hacketti) fossil wombats are known as well. Whether giant wombats were burrow-dwelling has been controversial. They possess some burrowing adaptations but don’t seem as well adapted for burrowing in digit morphology as extant forms. Woolnough & Steele (2001) argued that giant wombats were unlikely to be burrowers mostly on the basis of their size and the energetics involved, but this ignores the fact that some surprisingly large mammals (notably some ground sloths) are or were capable burrowers. However, Warendja from the Miocene and Pleistocene has thin, convex skull roof bones that seem incompatible with burrowing. Because it occupies a ‘basal’ position on the wombat cladogram (e.g., Archer 1984, Archer et al. 1999), it might be that burrowing characterises the clade that include extant wombats and their close relatives, rather than wombats as a whole (Phascolonus and Ramsayia are deeply nested within this clade, incidentally).

Of tails and trees

There are a few things worth saying about ancestral conditions in vombatiforms before we wrap up here. For all their morphological and behavioural diversity, all vombatiforms seem to have been mostly similar in basic body shape – they’re all rather barrel-chested, typically short-headed, quadrupedal marsupials with diprotodont dentition and diastema between the incisors and premolars. Palorchestids seem to be the most aberrant members of the group, with their long, narrow muzzles and highly apomorphic forelimbs. If the reasonably well-known Ngapakaldia is a primitive palorchestid, then we already know of taxa that seem intermediate in skull form between diprotodontids and highly modified palorchestids like Palorchestes.

Simplified vombatiform cladogram, ilariids and various other taxa not shown.

Because koalas, diprotodontids and wombats are short-tailed or tailless, it’s easy to assume that ancestral vombatiforms, vombatoids and diprotodontoids were similar. However, the presence of large, sometimes muscular tails in thylacoleonids and palorchestids (plus their presence in the vombatiform out-groups) implies that long tails were ancestrally present through the clade, and lost independently in koalas, diprotodontids and wombats at least. Strong adaptations for terrestriality in diprotodontids and wombats have also led to the general idea that vombatiforms as a whole are terrestrial marsupials, with koalas being specialised, arboreal descendants of terrestrial ancestors. However, the presence of climbing adaptations in koalas, thylacoleonids, vombatiform out-groups (the ‘possum’ lineages) and also in some zygomaturine diprotodontids implies that arboreality may have been primitive for vombatiforms (Weisbecker & Archer 2008). If so, then the terrestrial diprotodontoids and wombats have an arboreal ancestry.

And that’s it… I mean, as goes a very brief, whistle-stop tour of vombatiform diversity. Needless to say, there’s tons more to say, and I hope to elaborate on various of the groups discussed here in time. For previous Tet Zoo articles on marsupials and other metatherians, see…

PS – Tet Zoo ver 3 currently gets way less hits than Tet Zoo ver 2 (look at the NBN ratings to see progress). Not sure what I can do about that – any advice? Does it mean that lots of readers have just given up on Tet Zoo since the move, or is it that ver 2 still gets huge numbers of hits due to google?

Refs – -

Aplin, K. A. & Rich, T. H. 1985. Wynyardia bassiana Spencer, 1901. The Wynward marsupial. In Rich, P. V. & van Tets, G. F. (eds) Kadimaka. Extinct Vertebrates of Australia. Princeton University Press (Princeton, New Jersey), pp. 219-224.

Archer, M. 1984. The Australian marsupial radiation. In Archer, M. & Clayton, G. (eds) Vertebrate Zoogeography & Evolution in Australasia, pp. 633-808. Hesperian Press, Carlisle.

- ., Arena, R., Bassarova, M., Black, K., Brammall, J., Cooke, B. M., Creaser, P., Crosby, K., Gillespie, A., Godthelp, H., Gott, M., Hand, S. J., Kear, B. P., Krikmann, A., Mackness, B., Muirhead, J., Musser, A., Myers, T., Pledge, N. S., Wang, Y. & Wroe, S. 1999. The evolutionary history and diversity of Australian mammals. Australian Mammalogy 21, 1-45.

- ., Hand, S. J. & Godthelp, H. 1991. Riversleigh: the Story of Animals in Ancient Rainforests of Inland Australia. Reed Books, Kew (Victoria).

Black, K. 2007. Maradidae: a new family of vombatomorphian marsupial from the late Oligocene of Riversleigh, northwestern Queensland. Alcheringa 31, 17-32.

Camens, A., & Wells, R. (2009). Palaeobiology of Euowenia grata (Marsupialia: Diprotodontinae) and its Presence in Northern South Australia Journal of Mammalian Evolution, 17 (1), 3-19 DOI: 10.1007/s10914-009-9121-2

Flannery, T. F. & Archer, M. 1985. Palorchestes. Large and small palorchestids. In Rich, P. V. & van Tets, G. F. (eds) Kadimaka. Extinct Vertebrates of Australia. Princeton University Press (Princeton, New Jersey), pp. 234-239.

Johnson, C. 2001. Wombats. In Macdonald, D. (ed). The New Encyclopedia of Mammals. Oxford University Press, pp. 856-857.

Macphail, M. K. 1996. A habitat for the enigmatic Wynyardia bassiana Spencer, 1901, Australia’s first described Tertiary land mammal? Alcheringa 20, 227-243.

Munson, C. J. 1992. Postcranial description of Ilaria and Ngapakaldia (Vombatiformes, Marsupialia) and the phylogeny of the vombatiforms based on postcranial characters. University of California, Publications in Zoology 125, 1-99.

Murray, P. 1984. Extinctions downunder: a bestiary of extinct Australian Late Pleistocene monotremes and marsupials. In Martin, P. S. & Klein, R. G. (eds) Quaternary Extinctions: A Prehistoric Revolution. University of Arizona Press (Tucson), pp. 600-628.

Price, G. J. 2008. Taxonomy and palaeobiology of the largest-ever marsupial, Diprotodon Owen 1838 (Diprotodontidae, Marsupialia). Zoological Journal of the Linnean Society of London 153, 389-417.

Taylor, R. J. 1993. Observations on the behaviour and ecology of the Common wombat Vombatus ursinus in northeast Tasmania. Australian Mammalogy 16, 1-7.

Weisbecker, V. & Archer, M. 2008. Parallel evolution of hand anatomy in kangaroos and vombatiform marsupials: functional and evolutionary implications. Palaeontology 51, 321-338.

Woolnough, A. P. & Steele, V. R. 2001. The palaeoecology of the Vombatidae: did giant wombats burrow? Mammal Review 31, 33-45.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Dartian 8:03 am 10/29/2011

    a very brief, whistle-stop tour of vombatiform diversity

    And a real tour de force it was too. Fascinating stuff!

    is it that ver 2 still gets huge numbers of hits due to google?

    What counts as a ‘hit’? Are spambot visits included?

    Link to this
  2. 2. JennDeland 8:37 am 10/29/2011

    Two comments: First ever typo I have noticed in TetZoo (“largest marsupial that ever liked”) and, as for hits, you are buried in Scientific American’s mamoth site. It took me weeks to figure out how to subscribe, and if I don’t go in through my RSS reader, you’re almost impossible to find. Now that I friended you on Facebook, though, it’s easy! I think some of your followers may still be puzzled by the new location.

    Link to this
  3. 3. chris y 9:17 am 10/29/2011

    JennDeland is right about locating TZ3 without RSS. On the SciAm home page there’s no indication that you exist! I’ve grown used to finding your new posts via Bora’s notifications on G+, and now you’re there too I expect you’ll mention them yourself, but it does make it hard for casual users to drift onto your site.

    By the way, thanks for this little series, which was fascinating.

    Link to this
  4. 4. Cameron McCormick 9:36 am 10/29/2011

    “enough to have inspired the legend of the bunyip – or at least a few nightmares among Australia’s first Aboriginal inhabitants”

    Isn’t the only consistent trait of “bunyips” an aquatic habitat? The mention of “nightmares” is amusing, what with the Baku and all…

    Some people have illustrated it with a short, tapir-like trunk

    I suspect if given a horse skull, some people would reconstruct it with a trunk.

    Link to this
  5. 5. Andreas Johansson 10:44 am 10/29/2011

    Darren wrote:

    In Diprotodon, what appear to be two sexes were long regarded as two species (D. optatum is the big one; D. minor is the smaller one). It seems that this animal lived in small, gender-segregated herds (Price 2008).

    How was it concluded they’re in fact gender morphs?

    Regarding getting here, I just type “te” in my Firefox address bar and the google magic takes me here, but I can confirm it’s very hard to find TetZoo from the SciAm homepage. One doesn’t get the impression they regard the blogs as an important part of the site (not that there aren’t plenty other indications to that effect too).

    Link to this
  6. 6. naishd 10:44 am 10/29/2011

    Thanks for comments. I don’t think the SciAm blog layout is at all sensible (at least, not from a selfish blogger’s perspective) – no easily accessible list of bloggers, a very unhelpful search engine, no archives or list of recent articles, no list of recent comments. I can only hope that these things are ironed out in time.

    I have no idea what RSS feeds really are, or what they use them might serve, but people often ask for them. Mike P. Taylor says that the RSS feed for Tet Zoo ver 3 is…

    http://blogs.scientificamerican.com/tetrapod-zoology/feed/

    For those who don’t know, I do all I can on social media to promote new Tet Zoo articles. I tweet (@TetZoo), there’s a Tet Zoo facebook page that includes updates and ‘supplementary info’, and I’ve recently joined the tremendously non-user-friendly google+.

    And it does slightly nark me that people cry ‘bunyip’ whenever confronted with any weird-looking, extinct Australasian animal: Diprotodon, Palorchestes and Meiolania, for example, have all been mooted as ‘bunyips’ at times.

    Darren

    Link to this
  7. 7. BrianL 1:01 pm 10/29/2011

    Informative article!

    You refer to *Diprotodon* as the largest marsupial that ever lived. I remember reading, somewhere on the internet, that *Diprotodon* might in fact have achieved the largest attainable size for a marsupial. The reason for this was supposed to be the distance the new-born joey would have to crawl to the pouch. In marsupials even larger, this distance would be ‘too great’.

    I think this is bogus, as the joey probably increases in size and strength proportionally to the adult. Also I would explain the absence of even larger marsupials in Australia as being because Australia is a very dry and unproductive continent.
    Nevertheless, does anyone know if there could be a grain of truth in saying marsupials simply might not be able to grow beyond the dimensions of *Diprotodon*? Could an elephant-sized marsupial ever evolve, for example?

    Also, I seem to remember reading on Tet Zoo 2 that there had been zygomaturine fossils found on New Caledonia. Is that truly the case?

    Last but not least, I love that Peter Schouten painting of *Palorchestes*. It truly shows how odd these creatures must have looked to us humans and the joey only adds to that.

    Link to this
  8. 8. Mike from Ottawa 4:17 pm 10/29/2011

    “And it does slightly nark me that people cry ‘bunyip’ whenever confronted with any weird-looking, extinct Australasian animal … ”

    Naturally you’re annoyed. We all know the ‘bunyip’ is a misreported late-surviving gorgonopsian.

    BTW, how do we know some surprisingly large mammals like some ground sloths were burrowers? Not questioning the fact, but how we know is at least as interesting as what we know.

    Link to this
  9. 9. naishd 4:24 pm 10/29/2011

    How do we known some mylodontid sloths were burrowers? Because we’ve found their burrows, marked with their claw marks, and because their anatomy is consistent with this behaviour. This was covered here on Tet Zoo ver 2. Another big animals that ‘burrows’: the Pygmy hippo. In this case, the ‘burrows’ are better described as cave-like chambers. But they’ve been discovered, and confirmed as the products of Pygmy hippo construction.

    Darren

    Link to this
  10. 10. naishd 4:28 pm 10/29/2011

    BrianL (comment 7): For some discussion of the New Caledonian zygomaturine, go here on Tet Zoo ver 2 and search the comments.

    Darren

    Link to this
  11. 11. keesey@gmail.com 5:34 pm 10/29/2011

    What a fascinating clade! Thanks for these past two posts. I had not known that marsupial lions were stem-wombats.

    “[I]t might be that burrowing characterises the clade that include extant wombats and their close relatives, rather than wombats as a whole (Phascolonus and Ramsayia are deeply nested within this clade, incidentally).”

    This seems like another case where it would be better to limit the neontological terms to the crown clade. Reserve “wombat” for Clade(Lasiorhinus + Vombatus) and recognize things like Rhizophascolonus and Warendja as “stem-wombats” (or perhaps “near-wombats”).

    Link to this
  12. 12. CS Shelton 7:47 pm 10/29/2011

    “PS – Tet Zoo ver 3 currently gets way less hits than Tet Zoo ver 2 (look at the NBN ratings to see progress). Not sure what I can do about that – any advice?”

    Currently your “for other articles on…” section links back to ver 2, so every visitor to 3 is possibly throwing more traffic at 2, confusing the stats a bit. I know I’m personally always looking for something new so I come here first, but when I have the time, ver 2 is going to get hits from me.

    My partner’s website is slowly moving up in the world, which is quite a grind. I often find myself wondering, what is good traffic for a website? What does that number look like? And as that relates to commerce, when do you start offering merch?

    Did you ever move product with Tet Zoo? How did that go for you?

    Link to this
  13. 13. Christopher Taylor 9:24 pm 10/29/2011

    No mention of the supposed prehensile tongue of Euowenia grata? That seems to be one of those things that’s repeated in every popular book on the animals, without necessarily having much to support it.

    The other interesting thing about Euowenia is the manner of its naming. Long et al. (2002) reported it as, ‘The generic name was first described by De Vis as Owenia, in honour of Sir Richard Owen. When he subsequently realised that this generic name had already been used for an annelid worm, he renamed the genus Euowenia.’ Not quite true, as it happens: De Vis was not only fully aware of the worm genus when he named the diprotodontid, but he actually directly referred to it: ‘It is so clearly required by the fitness of things that the name of the expositor of the Extinct Mammals of Australia should have place in their nomenclature, that its occurrence more than once in our invertebrate lists fails to deter one from asking that it may be accepted where it has so much claim to acceptance’. Sadly, that last sentence seems fairly typical of De Vis’ composition style.

    Also I would explain the absence of even larger marsupials in Australia as being because Australia is a very dry and unproductive continent.

    True now, but the aridity of Australia is relatively recent; it was less so in the past.

    Link to this
  14. 14. CS Shelton 9:44 pm 10/29/2011

    Tet Zoo is like a happy-time drug for whatever is left of my childhood curiosity. I’m not sure what the appeal is exactly, but it feels important and endlessly fascinating to put this mural together in my head, to see the relationships of all things. The more I find out the more I’m frustrated we don’t know more, and the more I want to read on.

    I’m especially interested in what life looked like right after extinction events. I get the impression more than one branch of marsupial life made it through the K-T event. How do dinky insectivorous beasts branch out to become predators and prey and everything else? It’s something to see. Within vombatiforms alone we see the principle that every animal is a cannibal. Thylacoleonids eating diprotodonts. Om nom, as they say. Om nom nom.

    Link to this
  15. 15. erichmgf 12:46 am 10/30/2011

    Thanks Darren, nice coverage of these marsupials. For those with further interest in Palorchestes visit: http://museumvictoria.com.au/melbournemuseum/discoverycentre/600-million-years/timeline/quaternary/palorchestes/

    This previews Peter Trusler’s superb new reconstruction of the skull of Palorchestes azael, as well as restoration of its head (sans ‘tapir-like proboscis’), based on a newly discovered nearly complete skull of this species. For a video featuring Peter Trusler explaining the process of reconstructing Palorchestes, visit:
    http://museumvictoria.com.au/melbournemuseum/discoverycentre/600-million-years/videos/reconstructing-palorchestes/

    Link to this
  16. 16. Ranjit Suresh 1:08 am 10/30/2011

    You mention how Diprotodon is almost always depicted with shaggy brown hair. I’ve read that their hair remains have been found before – is this right?

    I would have predicted that such a large rotund mammal living in a range of semi-arid, warm temperate, and tropical habitats would have been nearly hairless like rhinos and hippos. I recall that “Walking with (Prehistoric) Beasts” depicted them as pachyderm-like in terms of integument.

    Link to this
  17. 17. Kelly Clowers 3:06 am 10/30/2011

    @Andreas Johansson
    That is Firefox magic, not Google magic – FF3+ has a feature called Awesomebar, where the URL bar does some complicated weighted searches on your bookmarks and history, as well as searching Google.


    As far as hits go, I am sure that two of the biggest issues are lack of Google visibility and lack of visibility on SciAm’s front page and blogger network page. It is unforgivable that SciAm would take a blogger on an then not provide a single link to them. It seems to indicate either massive incompetence, or a desire to see them fail. For that matter, lack of main page links to here is certainly harming this sites ability to grow it’s Google rank.

    Further issue are the login requirements and feed discoverablity. Even if they will not allow anon comments, they really should allow OpenID/Google/FB account connections.

    Feeds (whether RSS or the superior but lower mindshare Atom) are a way to either aggregate content in one place, and/or simply get notifications that new content is available. Which one or both depends on how a site is setup and how the user chooses to use it.

    A feed reader is an application or a website where you put in the URLs of feeds for sites you want to follow. Then when you click a button, visit the feed reader site or at a set time, the feed reader goes out and looks at each feed to see if there are new items. New items are then displayed for the use without them going to each site.

    Some apps use a email-like interface, as if each site was a mailbox, with an indicator if there are new items, others like Google Reader, use a “river of news” approach – as if it was your own personal [slashdot|digg|reddit|fark|whathaveyou].

    Some people see if they have new items and click the headlines that interest them to read them on the site, others may read part or all of the item in the reader. In order to get hits (aka ad revenue), many sites only put part of each article in the feed, if you want to read “beyond the jump”, you follow the link to the site. Some sites, especially webcomics, put only a title and date in the feed, since putting the one picture in there would keep people from ever visiting the site.

    So that is the theory of feeds, the point here is that the only link to the feed is the little orange feed icon next to the blog title. The symbol is universal across browsers and sites, but still little known to the general masses, and small and easy to overlook as well. Two things should be done: first, somewhere on the page there should be a text link to the feed that says “TetZoo RSS feed” or “subscribe to TetZoo (RSS)” or similar. Second, there need to be a <link> tag that points to the feed (I hope html entities work here, that should be “link” with angle brackets around it). It goes in the head tag of the web page, just like css, js and other “invisible” resources.

    For TetZoo it would look like this:
    <link rel=”alternate” type=”application/rss+xml” title=”RSS” href=”http://blogs.scientificamerican.com/tetrapod-zoology/feed/” /> (it would “application/atom+xml” if the site used Atom)

    This allows browsers to autodiscover the feed. In many/most browsers, an autodiscovered feed will make the feed icon show up in or next to the url bar – a consistent location that is much easier to find than hunting up and down the webpage for it. If I do not see the autodiscover icon (or my browsers equivalent) I tend to assume the site does not have a feed.

    Oh, one other thing: besides the new URL in the banner of the old site, there really, really needs to be a last post that just says “now at:” and the URL as a clickable link.

    This is because first, peoples eyes will slide right past the banner and not even see it. All they will see is the teasing post saying goodbye, they will not click and read to the bottom where it says that there is a v3 and where it is. Second,even if they do see the banner and the URL in it they cannot click on it (or rather the banner takes them right back to where they were), nor can they even copy and paste it into the URL bar. No, they have to type it by hand into the url bar. 98% of people will not make the effort.


    One of the first laws of web design is that users are fickle and will only put the smallest amount of effort into things. If it is even slightly difficult, they give up and move on. I have seen people search on Google, glance at the top 3 or 4 results and give up if it not there. The do not even check the whole ten on the first page! And this happens all the time, it is not some few very lazy people that do it. I don’t have the link to the study, but it was found a very high number of unsuccessful searchers never went to the second page of a search – over 90% I believe it was. Things may be a bit better for the TetZoo target audience, but probably not by much.

    Link to this
  18. 18. Kelly Clowers 3:13 am 10/30/2011

    Ugh, too tired to be posting, just look at all those spelling and punctuation errors!

    Link to this
  19. 19. Andreas Johansson 3:19 am 10/30/2011

    Kelly Clowers wrote:

    That is Firefox magic, not Google magic

    Er yes, don’t know what I was thinking. Google Chrome has something similar, but it doesn’t work as well.

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  20. 20. Andreas Johansson 4:22 am 10/30/2011

    And blockquote still doesn’t work here, sigh.

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  21. 21. BrianL 5:08 am 10/30/2011

    I knew the New Caledonian zygomaturine was referred to before at Tet Zoo 2, but the reason I brought it up again was because over there it had only the slightest mention. I can imagine it is a very obscure taxon, but I do wonder: Are we certain the creature hailed from New Caledonia? And if so, how did it end up at a place no other flightless terrestrial mammal ever appears to have reached? (Or does New Caledonia have native rodents?)Also, was it Holocene in age or more ancient? If it was more ancient, one wonders why it went extinct.

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  22. 22. Jerzy New 7:22 am 10/30/2011

    I read that hairy footprints of Diprotodon were found, but nothing more about it.

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  23. 23. BilBy 9:51 pm 10/30/2011

    TetZoo 2 gets more hits just because it is still bigger than TetZoo3 – articles here lead back to TetZoo 2 and it is just so damn interesting that one tends to lose a few hours wandering around that site gawping slack jawed. I think Sci Am needs to listen to you and your commenters a bit more and make TetZoo a bit more high profile and, please, a recent comments sidebar. With the old TetZoo discussions would start up on older articles all the time, which was fantastic.

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  24. 24. David Marjanović 11:43 pm 10/30/2011

    “a composite animal with tapir, chalicothere, pantodont, and slothlike features”

    Most awesome description (of… probably anything) I’ve ever read.

    Thanks for comments. I don’t think the SciAm blog layout is at all sensible (at least, not from a selfish blogger’s perspective) – no easily accessible list of bloggers, a very unhelpful search engine, no archives or list of recent articles, no list of recent comments. I can only hope that these things are ironed out in time.

    Hope?!?

    Dude, you’re dealing with complete and utter idiots. Raise a stink, or nothing will ever happen, because obviously they’re too stupid to get the idea that there even might be a problem.

    I find this site every day because it’s in my history. The URL isn’t very difficult to remember either.

    This is a science blog. We need some quote tag or other, we need a list of at least 10 recent comments. “Need” as in “need”. And I, for one, haven’t had trouble with registration, but I still prefer Captcha or ReCaptcha over registration.

    BTW, your goodbye post on ver 2 left it to the last sentence to clarify that, no, Tet Zoo wasn’t closing as the rest of the post made it sound, it was just moving. Judging from the comments, a scarily large number of people failed to notice that and are probably gone till Google or someone else tells them otherwise.

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  25. 25. Mythusmage 3:22 am 10/31/2011

    When are you doing a post about Mesozoic marsupials?

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  26. 26. Entelodon 4:53 am 10/31/2011

    Thanks for a fantastic summary, Darren. You mentioned the New Guinean zygomaturine, Hultitherium. I was wondering if you have seen a book called “Antipodean Ark” published in 1987? It was edited by Mike Archer and Sue Hand, and took the form of short essays by an array of Australian palaeontologists on selected regional palaeofauna accompanying black and white reconstructions by Peter Schouten. Tim Flannery wrote a piece about Hultitherium, speculating that it was a montane bamboo specialist, a marsupial panda-analogue. Schouten’s companion illustration is delightful, showing Hultitherium rearing bipedally in a bamboo thicket. I have no idea if Flannery explored this idea subsequently. Perhaps a C3/C4 isotopic study might be useful? Is bamboo’s carbon pathway similar to other grasses?

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  27. 27. Jerzy New 5:34 am 10/31/2011

    I also don’t understand why do you stay on the poorly designed blogsite. They offer everything for free or what?

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  28. 28. Andreas Johansson 9:23 am 10/31/2011

    David Marjanović wrote:
    Dude, you’re dealing with complete and utter idiots.

    Not that it makes a lot of practical difference, but I’m getting the impression of indifference rather than idiocy. They don’t seem to want to make the blogs easy to find or use.

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  29. 29. Heteromeles 10:03 am 10/31/2011

    @Entelodon: bamboo is a C3 grass, not C4, so I’m not sure isotopes would make a difference. If it ate wild Saccharum, that might matter, because sugar cane is C4, and it was domesticated on New Guinea. Of course, grasses aren’t the only C4 plants in the world, so isotopic tests aren’t definitive.

    The other thing that might be useful is microscopic examination of Hulitherium teeth. Grasses are rather abrasive, and if the teeth were prepared well, it’s possible that there would be evidence of wear from eating a high-silica diet.

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  30. 30. Robin Beck 12:00 pm 10/31/2011

    Great piece, as ever Darren. However, I’m quite confused by repeated mention of the ‘New Caledonian zygomaturine’. As far as I was aware, the last word on this specimen was in:

    Rich, T., Fortelius, M., Rich, P.V. & Hooijer, D.A. The supposed Zygomaturus from New Caledonia is a rhinoceros: a second solution to an enigma and its palaeogeographic consequences. Chap. 47:769-778. In: Archer, M. (ed.), Possums and Oppossums; Studies in Evolution. Surrey, Beatty & Sons, and the Roy. Zool. Soc. N.S.W., Sydney.

    These authors argued (pretty convincingly, as I recall) that the tooth is a premolar of a rhino, probably Rhinoceros sondaicus or Dicerorhinus sumatrensis – the overall resemblance is certainly a lot closer to a rhino than to any known zygomaturine. I’ve also found this new paper by Pierre-Olivier Antoine: http://www.rhinoresourcecenter.com/pdf_files/131/1313209161.pdf. Antoine states (page 8):

    ‘Neither fossil nor recent rhinocerotid is
    recorded in the Oceanian region, with the notable exception of a P1 unambiguously referable to the western Eurasian Miocene hornless teleoceratine Brachypotherium brachypus, found by gold diggers in New Caledonia in the 19th century. This tooth, probably used as a jewel by a French deported convict and subsequently lost by the Diahot River, was (mis)identified as documenting an in situ diprodontid marsupial of Australian affinities (Zygomaturus
    diahotensis; Guérin et al., 1981).’

    This raises several questions – what is the exact basis for concluding that the specimen is from Brachypotherium brachypus, and how on earth do we know it’s a jewel of a deported convict?! – but I don’t think anyone currently believes that the tooth in question is from a zygomaturine. However, I’m willing to be corrected…

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  31. 31. Jerzy New 3:05 pm 10/31/2011

    I think the tooth was brought by intelligent Triassic cephalopod using the time machine. Zygomaturines were commonly farmed as food for gorgonopsids and ropens. Or vice versa.

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  32. 32. Mu... 6:48 pm 10/31/2011

    In regards to the hits, on SB you were part of the “latest post” page that was one-page shopping for most of my favorite blogs. Now I have to actually click on your link to get here, something that doesn’t happen daily.

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  33. 33. David Marjanović 11:57 pm 10/31/2011

    I get the impression more than one branch of marsupial life made it through the K-T event.

    No good evidence for that, just a few ambiguously interpretable teeth from the Late Cretaceous of North America.

    Not that it makes a lot of practical difference, but I’m getting the impression of indifference rather than idiocy. They don’t seem to want to make the blogs easy to find or use.

    …which is… idiotic.

    The other thing that might be useful is microscopic examination of Hulitherium teeth. Grasses are rather abrasive, and if the teeth were prepared well, it’s possible that there would be evidence of wear from eating a high-silica diet.

    Actually, no. Phytoliths are softer than enamel. High-crowned teeth are an adaptation to sand in the food, not to grass.

    This explains the gondwanatheres, I suppose – Cretaceous mammals with high-crowned molars.

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  34. 34. Entelodon 5:04 am 11/1/2011

    Heteromeles and David, thanks for the responses. The 1987 Schouten reconstruction of Hulitherium turns out to be on Wikipedia at: http://en.wikipedia.org/wiki/File:Hulitherium_tomasetti.jpg

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  35. 35. BrianL 6:25 am 11/1/2011

    @Robin Beck:
    Thanks for explaining! I guess I misunderstood the order of things regarding that tooth. I had thought that the rhinoceros identification came first, only to be corrected to zygomaturine. Turns out the situation was the reverse. The suggestion that the tooth arrived as a possession (jewel or otherwise) of a colonist seems most plausible.
    Alas, no mammals for New Caledonia then!

    As for Hulitherium, what a bizarre creature.

    It does make me wonder: How often have quadrupedal mammals evolved habitual rearers and squatters?
    The examples I can think of of the top of my head are these:
    - Tripodals (resting on hindlimbs and a thick tail when rearing up): ground sloths, palorchestids and possibly *Plesiorycteropus* and *Barylambda*. Do macropods count?
    - Bipedal rearers (not using tail-assistance): Gerenuk and chalicotheres. Goats, deer and elephants occassionnally rear but not habitually so, I believe.
    - Squatters (Resting on their hunches or hindquarters while feeding): Giant pandas, gorillas and geladas. *Chapalmalania* perhaps?

    If more examples could be added I’d be delighted.

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  36. 36. Dartian 8:31 am 11/1/2011

    Brian:
    Could an elephant-sized marsupial ever evolve

    Depending on what, precisely, you mean by ‘elephant’ you might say that Diprotodon was already elephant-sized. With an estimated body mass of 2,700 kg, it would have been about as heavy as a typical African forest elephant Loxodonta cyclotis female. Pointing out this isn’t just pure pedantry, either; it’s good to keep in mind that truly gigantic proboscideans only really started to evolve in the Late Neogene (even though the proboscidean lineage can be traced back to the mid-Eocene at least). The Pleistocene Diprotodon optatum would have been comparable in size to your typical Miocene mastodon; who knows how large a size some diprodontids might have attained had they had another 10-15 million years of time to evolve?

    does New Caledonia have native rodents?

    No. The Polynesian rat Rattus exulans was already present on the island when Europeans first arrived there, but it had almost certainly been brought there by native people (as it has been to so many other Pacific islands); nowadays, of course, Rattus rattus, Rattus norvegicus and Mus musculus are present in New Caledonia too. But no, there are no endemic native rodent species there.

    Regarding “the last word” on the NC zygomaturine: Robin (or anyone), would you happen to remember any more details from that Rich et al. paper? It’s a reference that I haven’t seen (and indeed wasn’t even aware of until reading this thread). Those who originally (1981) suggested a zygomaturine identity for that NC tooth included Claude Guérin, who was (is?) an authority on rhinos, including fossil ones; experts, of course, sometimes make mistakes too, but I wouldn’t have expected him, of all people, to have made a misidentification so widely off the mark. What I do know is that in a later publication, Guérin & Faure (1987) were still holding on to their interpretation that the tooth belonged to a zygomaturine and not to a rhino.

    Brian (again):
    I had thought that the rhinoceros identification came first, only to be corrected to zygomaturine. Turns out the situation was the reverse.

    Er, the rhino ID did come first. The chronology of events, as far as I’ve been able to reconstruct it, goes like this:
    -1870-1876: The tooth is (allegedly) discovered in “Plio-Pleistocene” deposits in Diahot Valley, New Caledonia, by miners.
    -1876: The tooth is described as that of a rhinoceros by the French naturalist Henri Filhol.
    -1981: Guérin et al. publish a paper where they compare the tooth to those of (extant) rhinos and various diprotodontids, and conclude that it is more similar to those of the latter, and specifically Zygomaturus‘; hence, they name it a new species, Zygomaturus diahotensis.
    -1987: The Rich et al. book chapter, where the tooth is (apparently) re-identified as that of a rhinoceros, is published.

    References:
    Guérin, C. & Faure, M. 1987. A propos du Zygomaturus, diprodontidé de Nouvelle-Calédonie. Comptes Rendus de l’Académie des Sciences, Série II 305, 815-817.

    Guérin, C., Winslow, J.H., Piboule, M. & Faure, M. 1981. Le prétendu rhinocéros de Nouvelle Calédonie est un marsupial (Zygomaturus diahotensis nov. sp.): solution d’une énigme et consequences paléogéographiques. Géobios 14, 201-217.

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  37. 37. Robin Beck 9:23 am 11/1/2011

    Dartian:

    Unfortunately, I don’t own a copy of ‘Possums and Opossums’, and the Rich et al. chapter was one I didn’t photocopy. I don’t remember too much about the chapter, other than that authors showed images of rhino premolars (sorry, can’t remember the species!) that appeared very, very close in overall morphology to the New Caledonian tooth, and far more similar than the *Zygomaturus* specimens they illustrated. I realise that this isn’t much help – does anyone have a copy of the chapter to hand?!

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  38. 38. Heteromeles 12:33 pm 11/1/2011

    @32 David Marjanović: Really? The silica phytoliths in grasses are softer than heterogeneous sand (which, btw, is a grain size, not mineral composition. Sand can be calcium carbonate, for instance)? I find that hard to believe.

    More to the point, AFAIK, bamboo can be more abrasive than the surrounding dicots, so if an animal is a specialized bamboo eater, I’d be surprised if there was no evidence from their teeth.

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  39. 39. David Marjanović 12:47 pm 11/1/2011

    Really? The silica phytoliths in grasses are softer than heterogeneous sand [...]?

    It’s a bit hard to imagine, but there’s a paper or at least an SVP meeting abstract on it. I’ll have to look for it sometime. And yes, I should probably have said “silicate dust” instead of “sand”; and yes, you’re almost certainly right about microwear – I’m not sure why I brought up macrowear in the first place.

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  40. 40. Mike from Ottawa 1:02 am 11/2/2011

    “Another big animals that ‘burrows’: the Pygmy hippo.”

    OK, that’s my ‘Mind-Blowing Fact Discovered at TetZoo of the Week’.

    I must have missed the bit about the ground sloths burrowing in the TetZoo2 article because I was agog at the marine sloths.

    Thx, Darren, for once more making my week!

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  41. 41. Mythusmage 1:38 am 11/2/2011

    I recall a report once about savannah elephants who would visit a hill in a forest to get minerals. They dug out the minerals using their tusks and ingested them. By the time the footage was shot they they had dug into the hill side and were walking inside the excavation to obtain the dirt they ate for its mineral content. In short, you had burrowing elephants for all intents and purposes. :)

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  42. 42. farandfew 6:44 am 11/2/2011

    Dammit. I promised to get hold of references about the New Caledonian zygomaturine/rhino in a comment thread on Tet Zoo 2. I suppose I had better do so. If I don’t Dartian please ask Darren to nag me.

    Incidentally I’m surprised to see Darren not displaying skepticism about the trunk of Palorchestes. But perhaps that’s just because it would balloon the article.

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  43. 43. falcon121 7:56 am 11/2/2011

    How about a series on dasyurids??

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  44. 44. Dartian 8:12 am 11/2/2011

    Regarding ‘burrowing’ pygmy hippos: Pygmy hippos use burrows, yes (at least some individuals, in some parts of their distribution range – see Robinson, 1981), but have they ever been observed to actually dig them (as opposed to just taking over an already existing burrow)?

    Mythusmage:
    you had burrowing elephants for all intents and purposes

    …except that this kind of excavation process will take decades or perhaps even centuries.

    Farandfew: I would be interested in that Rich et al. paper if you happen to have it. Those two papers that I cited in comment #35 I now possess (unlike back when we discussed this subject on TetZoo ver 2).

    Reference:
    Robinson, P.T. 1981. The reported use of denning structures by the pygmy hippopotamus Choeropsis liberiensis. Mammalia 45, 506-508.

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  45. 45. John Scanlon FCD 11:36 am 11/2/2011

    “highly inflexible wrists and ankles”

    Rilly? The ulna has a strikingly spherical knob on the distal end, implying pretty free rotation (under load). Diprotodontids are pretty unusual in being plantigrade front and back (the tibia’s not so obviously derived though).

    I’ve got ‘Possums and Opossums’ here, what do folks need to know? Rich et al.’s the very last paper in Vol 2; the citations start with Filhol (1876); apparently Guérin et al. (1981) relied on Stirton et al’s (1976) line drawings for all their comparative data on zygomaturines. Rich et al. reproduce photos of the Diahot tooth from Guérin next to a dm1 of ‘Eurhinoceros aff. sondaicus’ (from Hessig 1972) which seems a fair match, and also illustrate several upper p3s of Z. trilobus, the upper milk dentition of Rhinoceros sondaicus, lower right premolars of Chilotherium habereri, upper right premolars of R. unicornis, micrographs of worn enamel surfaces of the Diahot tooth, Z. trilobus and D. optatum.

    I haven’t made a particular study of mammals but remember reading the paper before publication [helped write the index] and since then I’ve been unable to avoid seeing and handling quite a few zygomaturine premolars at various stages of evolution (Oligocene to Pleistocene). ‘Zygomaturus’ diahotensis just doesn’t look like one. Case closed, OK? :)

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  46. 46. Jerzy New 6:22 pm 11/2/2011

    Regarding giant burrowing animals (I think I explained this somewhere before, but maybe not):

    If you dig too big burrow, the ground collapses. I saw a mention somewhere that this type of stability of different soils is precisely established, because it is important for building industry etc.

    Which probably allows animal to “cheat”. Very big animal which is long and very low, like Nile crocodile, can squeeze into small burrow. Animal might dig tunnel partially under hard rock or whatever. And perhaps water can erode karst-like tunnels in soils too hard for animals to dig, but animals can use and perhaps a little enhance them.

    Still, it might be possible to calculate the absolute upper height limit of burrowing animals.

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  47. 47. BilBy 9:45 pm 11/2/2011

    @Jerzy – What about the difference between ‘burrowing’ and ‘fossorial’? A big animal can make a burrow – aardvarks are surprisingly HUGE if you’ve only ever seen a picture of one before, but they don’t live underground. I thought the biggest ‘true, burrowing, fossorial, underground dwelling’ beast was something like a Cape dune mole rat, Bathyergus suillus, and they only get to about 2kg max I think. How much time does an organism have to spend underground and/or have what adaptations before it becomes fossorial as opposed to a burrow digger?

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  48. 48. Dartian 3:26 am 11/3/2011

    John:
    ‘Eurhinoceros aff. sondaicus’

    Lest there be any confusion, it should perhaps be noted here that Eurhinoceros Gray, 1867 is a junior synonym of Rhinoceros Linnaeus, 1758; thus, by ‘Eurhinoceros sondaicus‘ would be meant the Javan rhinoceros.

    Case closed, OK?

    Not quite. There is still the question of which rhinoceros species the tooth belongs to. If Rich et al. thought that it was that of a Javan, or perhaps a Sumatran, rhino, then where on earth does the suggestion that it belongs to the Miocene Eurasian Brachypotherium brachypus (see comment #29) come from?!

    Bilby:
    How much time does an organism have to spend underground and/or have what adaptations before it becomes fossorial as opposed to a burrow digger?

    There is no strict definition of ‘fossorial’ AFAIK, but as a rule of thumb, it might be said that a fossorial species is one that typically does its foraging underground (as opposed to merely using burrows as shelters).

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  49. 49. Jerzy New 5:19 am 11/3/2011

    @BilBy
    I, like Dartian, thought that fossorial animals feed underground. But there are some rodents called fossorial which actually feed on vegetation (mostly?) from above ground.

    I guess biggest existing burrowing animal would be Nile crocodile, although I don’t know if big crocs burrow and how deep are those burrows. But the size limit of a burrow is perhaps just above height of aardvark, warthog, pygmy hippo etc.

    When an animal is actively moving in the soil, like a mole, then size limit is much smaller. Animal crawling in the earth must push and compact soil to the sides, and this is very energetically expensive. Somebody said before that largest burrowing amphisbaenians etc are just few cm across. Moles and burrowing rodents can grow a bit bigger, because they push out excavated material, and mostly have permanent tunnels.

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  50. 50. jwmorenob 5:23 am 11/3/2011

    “I have no idea what RSS feeds really are, or what they use them might serve, but people often ask for them. Mike P. Taylor says that the RSS feed for Tet Zoo ver 3 is…

    http://blogs.scientificamerican.com/tetrapod-zoology/feed/

    I have just discovered, after trying several times, that this RSS feed link works perfectly for the blogroll gadget of my blog. Several blogs do not have proper links to tetzoo3 because the “normal” url just directed you to the scientific american blogs site, not to tet zoo.

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  51. 51. Dartian 5:58 am 11/3/2011

    Jerzy:
    I guess biggest existing burrowing animal would be Nile crocodile, although I don’t know if big crocs burrow

    While they’re not the largest mammals that truly burrow, ringed seals Pusa hispida are large enough to deserve a mention here; their females excavate dens for their pups in the pack ice (incidentally demonstrating that even species highly specialised for aquatic living may be able to dig).

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  52. 52. vdinets 11:30 am 11/3/2011

    Dartian,
    Ringed seals (and a few other small seals) excavate dens in compacted snow layer on top of the ice, not in the ice itself.

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  53. 53. Dartian 1:35 am 11/4/2011

    Ringed seals (and a few other small seals) excavate dens in compacted snow layer on top of the ice, not in the ice itself.

    Well duh! The term ‘pack ice’ refers to a type of habitat rather than to some specific substrate. (Icebergs contain lots of snow too, but we don’t call them ‘snow-and-icebergs’.)

    Besides, in order to reach – from below – that layer of snow on the top, seals usually do have to dig through a layer of real ice too. (Granted, seals probably follow the path of least resistance and preferentially choose spots where there already are cracks in the ice. But dig with their claws they must do; seals don’t have frickin’ laser beams attached to their frickin’ heads.)

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  54. 54. Dartian 1:47 am 11/4/2011

    But dig with their claws they must do

    …and yes, I know that the Weddell seal Leptonychotes weddellii would use its teeth rather than its claws. But we were talking about Pusa seals here.

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  55. 55. welsh peregrine 9:50 am 11/4/2011

    While we are, at least peripherally, talking about Ringed seals, anyone able to throw some light on a little mystery. I’m thinking of visiting Lake Samaa (or whatever the correct spelling is) next year, and while trying to find information on this population, came across a reference in Grzimek’s encyclopaedia of a population in China’s Lake Kokonor. Nowhere else seems to mention this population. Anyone know anything more?

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  56. 56. Jerzy New 10:19 am 11/4/2011

    @welsh peregrine
    There was most certainly no seals in Koko Nur.

    Darren, I looked at other blogs in scientific american and noted, that they are findable mostly by list search. Your blog is on T so near the end. Did you think about changing, for example, to “Aardvark to Zygosaurus: tetrapod zoology”?

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  57. 57. welsh peregrine 12:00 pm 11/4/2011

    Any idea where Grzimek’s info might have come from?

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  58. 58. Andreas Johansson 1:40 pm 11/4/2011

    The Finnish lake is called Saimaa (or Saimen in Swedish).

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  59. 59. vdinets 4:07 pm 11/4/2011

    Dartian: They don’t drill through ice with their claws, unless it’s really soft. Instead, they find natural openings and maintain them. That’s one reason why they normally avoid old ice, preferring softer, more fragmented ice formed previous fall on the periphery of the polar ice cap. The only Arctic species known to habitually breed on old ice is the hooded seal (some populations), but it only needs to stay on the ice for less than a week due to extremely short lactation time, so it’s easier for these seals to maintain openings.

    Welsh Peregrine: the Kukunor seals are a local version of Loch Ness monster. The lake is currently called Qinghai (the Chinese have replaced all Mongolian names in Tibet with Chinese ones), and visited by a lot of people; there’s a lot of farmers along the shores, plus a nature reserve, so if there were seals in the lake, there would be specimens.

    Link to this
  60. 60. Mythusmage 5:59 pm 11/4/2011

    #43

    …except that this kind of excavation process will take decades or perhaps even centuries.

    Who said the burrowing has to be accomplished overnight?

    Link to this
  61. 61. Dartian 5:27 am 11/5/2011

    Vladimir Dinets: Your attempts at shifting the goal-posts are noted.

    Mythusmage:
    Who said the burrowing has to be accomplished overnight?

    It doesn’t have to happen “overnight” but the burrow/den/cave construction really should at least happen during, you know, the individual animals’ lifetimes (elephants are pretty long-lived, but even they don’t live for centuries). Frankly, IMO, what those elephants do doesn’t really qualify as digging/burrowing as the ‘digging’ isn’t intentional.

    Link to this
  62. 62. Mythusmage 10:54 pm 11/6/2011

    Dartian,

    It looks like burrowing, and it acts like burrowing, then it’s burrowing. You, sir, are being a bit too fussy for your own good.

    Link to this
  63. 63. Dartian 6:51 am 11/7/2011

    It looks like burrowing, and it acts like burrowing, then it’s burrowing.

    Really now? You know for a fact that the Mount Elgon caves have been dug by elephants? Because if you do, you must be in possession of more information than the geologists who’ve actually studied these caves. They don’t claim that the elephants are the only – or even the main – reason for the formation of the Mount Elgon caves (in fact, large parts of these caves are physically beyond the reach of any elephant). Regarding terminology, by the way: the term that usually seems to be used to describe the elephants’ geophagous activities is ‘tusking’ (not ‘digging’ or ‘burrowing’).

    But, Mythusmage, if you really do know something that those geologists don’t, then please by all means write that up and publish it in the scientific literature.

    Link to this
  64. 64. welsh peregrine 7:50 am 11/7/2011

    Thanks to vdinets for reply – I’ve been fortunate enough to go Birding in the vicinity of Kokonur/Qinghai (seeing Bar-headed Geese and six species of Snowfinch) but was not aware of the seal “myth” at the time. Is there any info on the seal stories anywhere (just curious about it as yet another Lake Monster story)?

    Link to this
  65. 65. vdinets 12:11 pm 11/7/2011

    Welsh_Peregrine: there is a similar legend at Lake Lobnor in Xinjiang, which is more remote. In Western literature it is often stated that Caspian seal occurs also in Aral Sea; I have no idea how that error arose. No other seal stories as far as I know, although in general it is hard to find a large lake in Asia with no monster stories. The best-known ones are about Lake Labynkyr in Yakutia and Lake Van in Turkey.

    Link to this
  66. 66. Mythusmage 9:12 pm 11/10/2011

    #63,

    That is the impression I was given by the report, though it’s been years since I saw it.

    Link to this

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