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All the whales of the world, ever (part I)

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


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Whole cetacean cladogram, from Geisler et al. (2011). Click to enlarge (preferably: download the paper - it's open access).

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It’s apparently a good idea in scientific blogging to produce ‘clearing house’ blog articles every now and again: that is, articles that include links to all of your other articles on a given subject. I suppose anything that gets people looking anew at old articles and reminding them what you have ‘in the archives’ is a good idea.

With all of this in mind, I decided for no particular reason to create a CETACEA clearing house. Well, that’s not entirely honest – I suppose there are two reasons why I might benefit from publishing this. One being that I want links to all of my cetacean content in the same place; the other being that articles about cetaceans are perennially popular, and reminding people that they exist is a good move as I strive desperately to get more hits*. And this is not a bad time to talk about whales in a phylogenetic context, since a large number of studies published in recent years have aimed to piece together the different section of the whale family tree.

* Tet Zoo ver 3 is still getting less hits than ver 2. I’m sure (transl. = I hope) things will change eventually.

The aim of this article (aaaand the following one), then, is to whiz briefly through the whole of cetacean diversity, all the while providing links to previous Tet Zoo articles that guide the reader where to go should they want to read more about the specific groups we meet on the way. As we’ll see, coverage of the different cetacean clades has actually been fairly even, and they makes me happy. Off we go. We start in the Eocene…

Whales of the Eocene: from pakicetids to Basilosaurus, Dorudon and more

Reconstructed Pakicetus attocki skeleton.

Stem-cetaceans – the archaic, sometimes amphibious or semi-terrestrial Eocene forms – are all the rage these days, with exciting new discoveries appearing fairly regularly in top tier journals and hence on the newswires. It turns out that the very oldest cetaceans – the Asian pakicetids – weren’t seal-like protowhales as once thought, but morphologically more like slim-snouted artiodactyls (Thewissen et al. 2001). Exactly where these slender-limbed, at least partly terrestrial little hoofed mammals fit with respect to other early artiodactyls is mildly controversial. Indeed, it’s now generally agreed that Cetacea is deeply nested within Artiodactyla, and I see no point at all in using the name ‘Cetartiodactyla’ for the version of Artiodactyla that’s understood to include Cetacea. Thewissen et al. (2007) argued that cetaceans are closest to the raoellids (see also Spaulding et al. (2009)), and that even raoellids were aquatic waders that spent time swimming in and under the water. However, other authors still find mesonychians to be closest to cetaceans (O’Leary & Gatesy 2008), though with the mesonychian + whale clade being deep within Artiodactyla.

Pakicetids seemingly gave rise to the larger, longer-snouted ambulocetids [Pakicetus skeleton above photographed by Ghegoghedo]. The precise relationships among the other Eocene cetacean groups haven’t yet been resolved with confidence, but the particularly odd, very long-snouted remingtonocetids and a paraphyletic assemblage of robust-bodied forms conventionally termed protocetids seem successively closer to Pelagiceti, the clade that includes all those fully aquatic cetaceans with reduced or absent hindlimbs (Uhen 2008). ‘Protocetids’ include reasonable diversity: the most familiar forms, like Protocetus and Rodhocetus, might have looked something like a cross between a big seal and a deep-bodied artiodactyl, albeit it with large, webbed feet and a stout tail (Gingerich et al. 2001, 2009). Some were badass predators: the ‘baby’ whale inside Maiacetus inuus might actually be the remains of a consumed prey item.

Replica skull of the gigantic, geographically widespread basilosaurid Basilosaurus.

Pelagicetans include the famous long-bodied Basilosaurus and its possible close relatives (Cynthiacetus, Basiloterus) and Dorudon and other ‘dorudontids’ (Chrysocetus, Zygorhiza, Saghacetus, Stromerius etc.). Dorudontid-grade pelagicetans were highly similar to modern whales in general proportions, but still had hindlimbs and an archaic, heterodont dentition. We now know that archaic pelagicetans survived beyond the end of the Eocene and into the Oligocene and perhaps the Miocene. The group concerned – the kekenodontids – were apparently similar to Dorudon and kin in being fusiform and pelagic. Anyway, I haven’t much covered any of these archaic cetaceans at Tet Zoo…

Life restoration of a dorudontid by Tony Pyrzakowski, though done back before it was widely recognised that they possessed small hindlimbs (with knees, ankles and toes).

With these archaic forms out of the way, we turn to crown-group cetaceans, termed Neoceti (so far as I know, no-one has suggested that the term Cetacea be restricted to the crown). Early on in its history, Neoceti diverged into Mysticeti and Odontoceti.

Baleen whales: rorquals, grey whales, right whales and their relatives

Mysticetes or baleen whales are familiar enough animals, but the fossil record shows that the oldest stem forms (the Oligocene mammalodontids) were relatively small with relatively small skulls, a heterodont dentition and a relatively short, deep rostrum. Some of these animals may have been beluga-like generalist feeders that used suction to capture benthic animals (Fitzgerald 2009) while others had more robust rostra and were able to kill and handle reasonably big vertebrate prey. From mammalodontid-like ancestors, the longer-skulled, flatter-snouted (but still toothed) aetiocetids evolved. Aetiocetids (Aetiocetus, Chonecetus, Ashorocetus and Morawanocetus) may have indulged in some filter-feeding, but their small, conical teeth and occlusal wear facets suggest that they were still catching small prey with their teeth (Deméré et al. 2008, Fitzgerald 2009).

Blue whale skeleton at NHM, London.

Toothless mysticetes – grouped together as Chaeomysticeti – possess relatively enormous skulls and laterally bowed mandibles. All fossil forms have specialisations related to bulk filter-feeding, and crown-mysticetes like rorquals are of course able to engulf literally tons of prey and water in a single mouthful (or, at least, the giant species are).

An assemblage of fossil mysticetes that (grotesque generalisation) look superficially like prototype versions of the living species were previously lumped together as ‘cetotheres’ (and sometimes regarded as close relatives, or ancestors, of the living Grey whale – read on). The term cetothere in the strict sense (as in, Cetotheriidae) is now restricted to the clade that comprises Piscobalaena, Herpetocetus, Metopocetus, Cetotherium, Nannocetus and Mixocetus (Bouetel & Muizon 2006, Steeman 2007, Geisler et al. 2011). Cetotheriids proper are united by distinctly wedge-shaped nasal bones (look at Metopocetus below) and a list of other skull bone characters.

Selection of fossil mysticete skulls, from Pilleri & Pilleri (1989).

Additional fossil mysticetes that were classified in the new ‘families’ Pelocetidae, Aglaocetidae and Diorocetidae by Steeman (2007) have been regarded as especially close relatives of balaenopterids by some authors (Steeman 2007), but as stem-mysticetes by others (Bouetel & Muizon 2006, Geisler et al. 2011). Geisler et al. (2011) used the name Balaenomorpha for Diorocetus, Pelocetus and crown-mysticetes. Cetotheriids definitely deserve coverage on Tet Zoo some time, as do the also extinct eomysticetoids (eomysticetids and cetotheriopsids).

Crown-mysticetes belong to one of two lineages: the right whale lineage, and the rorqual + grey whale lineage (though read on for complications). Right whales are well known for their massive arched upper jaws, incredibly long baleen and remarkable rotund proportions. Their fossil record perhaps extends back to the Upper Oligocene, and the Lower Miocene form Morenocetus shows that the ‘modern’ right whale skull form has been around for more than 20 million years. There’s nothing of substance about right whales on Tet Zoo, only…

Blue whale as seen from the air; photo by NOAA Fisheries.

The other living mysticetes have been written about a fair bit at Tet Zoo, largely because rorquals and humpbacks (classified together as Balaenopteridae) amaze me in having crazy distensible jaws, pleated, expandable throat skin, and an amazing ability to morph from a streamlined torpedo shape into a fat, bloated tadpole. The largest cetacean, largest mammal and largest tetrapod is, of course, a member of this group. Balaenopterids grow quickly, with even Blue, Fin and Sei whales reaching sexual maturity in a decade or less: Minke and Humpback whales may be sexually mature at just two or three years of age (Sigurjónsson 1995). A review of living and fossil balaenopterid diversity was provided by Deméré et al. (2005).

Both right whales and balaenopterids have suffered tremendously from the whaling industry: the populations of species that are no longer hunted are now a tiny fraction of what they used to be, but there are indications that some of these (e.g., the Antarctic Blue whale Balaenoptera musculus population) are now stable or perhaps increasing. There are of course concerns about the future of these animals given climate change, increases in global shipping, and damage to their hearing caused by low-frequency sonar.

Grey whale; photo by Joan Lopez.

The Grey whale/Gray whale Eschrichtius robustus is a peculiar coast-hugging mysticete with coarse baleen and a distinctive series of low bumps running along the top of its back and tailstock [adjacent photo from here]. The scientific name we presently used was originally given to fossils from Sweden, and only later was it realised that this was the same animal as the living whale of the north Pacific coasts. One of the most remarkable recent stories concerning Grey whales is the discovery of a live individual in the eastern Mediterranean Sea. That’s a bizarre and fascinating thing, but I can’t help but feel that it might be bad news – are things really so bad for these whales that they’re having to move well away from their feeding grounds? The Grey whale was once regarded as a close relative or descendant of the cetotheres but is most likely a close relative of the balaenopterids (though see Steeman (2007) where there is a Cetotherioidea clade that includes grey whales and cetotheriids).

A live, stranded Caperea.

Caperea – the Pygmy right whale – is an unusual and little-known mysticete that, while once regarded as a close relative of the right whales, may in fact be closer to balaenopterids. Geisler et al. (2011) proposed the new name Plicogulae for the clade that includes Caperea, balaenopterids and grey whales. I’m pleased to say that Caperea has been written about quite a few times on Tet Zoo.

Part II: odontocetes!

Refs – -

Bouetel, V. & de Muizon, C. 2006. The anatomy and relationships of Piscobalaena nana (Cetacea, Mysticeti), a Cetotheriidae s.s. from the early Pliocene of Peru. Geodiversitas 28, 319-395.

Deméré, T. A., Berta, A. & McGowen, M. R. 2005. The taxonomic and evolutionary history of fossil and modern balaenopterid mysticetes. Journal of Mammalian Evolution 12, 99-143.

- ., McGowen, M. R., Berta, A. & Gatesy, J. 2008. Morphological and molecular evidence for a stepwise evolutionary transition from teeth to baleen in mysticete whales. Systematic Biology 57, 15-37.

Fitzgerald, E. M. G. 2009. The morphology and systematics of Mammalodon colliveri (Cetacea: Mysticeti), a toothed mysticete from the Oligocene of Australia. Zoological Journal of the Linnean Society 158, 367-476.

Geisler, J. H., McGowen, M. R., Yang, G. & Gatesy, J. 2011. A supermatrix analysis of genomic, morphological, and paleontological data from crown Cetacea. BMC Evolutionary Biology 2011, 11:112 http://www.biomedcentral.com/1471-2148/11/112

Gingerich, P. D., Haq, Mu, Zalmout, I. S., Khan, I. H., & Malkani, M. S. (2001). Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan. Science, 293 (5538), 2239-42 PMID: 11567134

- ., ul-Haq, M., von Koenigswald, W., Sanders, W. J., Smith, B. H. & Zalmout, I. S. 2009. New protocetid whale from the Middle Eocene of Pakistan: birth on land, precocial development, and sexual dimorphism. PLoS ONE 4(2): e4366. doi:10.1371/journal.pone.0004366

O’Leary, M. A. & Gatesy, J. 2008. Impact of increased character sampling on the phylogeny of Cetartiodactyla (Mammalia): combined analysis including fossils. Cladistics 24, 397-442.

Pilleri, G. & Pilleri, O. 1989. Bartenwhale aus der Pisco-Formation Perus. In Pilleri, G. (ed) Beiträge zur Paläontologie der Cetacean Perus. Hirnanatomisches Institut (Bern, Switzerland), pp. 11-38.

Sigurjónsson, J. 1995. On the life history and autecology of North Atlantic rorquals. In Blix, A. S., Walløe, L. & Ulltang, Ø. (eds) Whales, Seals, Fish and Man. Elsevier Science, pp. 425-441.

Spaulding, M., O’Leary, M. A. & Gatesy, J. 2009. Relationships of Cetacea (Artiodactyla) among mammals: increased taxon sampling alters interpretations of key fossils and character evolution. PLoS ONE 4(9): e7062. doi: 10.1371/journal.pone.00070672

Steeman, M. E. 2007. Cladistic analysis and a revised classification of fossil and recent mysticetes. Zoological Journal of the Linnean Society 150, 875-894.

Thewissen, J. G. M., Cooper, L. N., Clementz, M. T., Bajpai, S. & Tiwari, B. N. 2007. Whales originated from aquatic artiodactyls in the Eocene epoch of India. Nature 450, 1190-1195.

- ., Williams, E. M., Roe, L. J. & Hussain, S. T. 2001. Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls. Nature 413, 277-281.

Uhen, M. D. 2008. New protocetid whales from Alabama and Mississippi, and a new cetacean clade, Pelagiceti. Journal of Vertebrate Paleontology 28, 589-593.

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!

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





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  1. 1. Christopher Taylor 4:52 am 12/6/2011

    Cetotheriids definitely deserve coverage on Tet Zoo some time, as do the also extinct eomysticetoids (eomysticetids and cetotheriopsids).

    I can claim to have had a guest appearance by Eomysticetus in one of my own posts.

    I also have to confess, Darren, that whenever I see you complain that you’re not getting enough page views, I feel the urge to reply: Shut up, Gingrich.

    Link to this
  2. 2. naishd 5:01 am 12/6/2011

    I can understand the “shut up” bit, but not the Gingrich reference. Say what?

    Darren

    Link to this
  3. 3. farandfew 5:43 am 12/6/2011

    Sooo…. Pakicetus, right?
    Are those thick earbones likely to be related to hearing underwater?
    Because I’m picturing the beast wading in the waters margins listening for gobies and crabs moving on or in the mud and snapping them up with that pointy jaw.
    Really, whatever its astralagus is doing, it doesn’t look much like an antelope. More like a solenodon or something.

    Link to this
  4. 4. kattatogaru 6:20 am 12/6/2011

    Hi Darren, one of the reasons that you don’t get so many hits on Tet Zoo 3 is that there are LOTS of links in other sites to Tet Zoo 2… AND blogroll links to Tet Zoo 3 often take you to the generic Sci Am blog front page or some other, unwanted and irrelevant Sci Am blogger’s wafflings (!!!). It took me quite a while to work out how to get to this one reliably… now through (horrors) facebook. Otherwise I had to keep googling text I remembered from the previous entries on Sci Am 3.

    Link to this
  5. 5. Cameron McCormick 7:16 am 12/6/2011

    Basilosaurus and its possible close relatives (Cynthiacetus, Basiloterus)

    Uhen (2010) mysteriously states that Basilosaurus drazindai and Basiloterus hussaini are “probably” protocetids. Since B. drazindai had vertebrae around the same size as those from B. isis and B. cetoides… the implication is that there were gigantic protocetids.

    Uhen, M. D. (2010). The Origin(s) of Whales. Annu. Rev. Earth Planet. Sci. 38, 189–219. Availablet

    Link to this
  6. 6. Christopher Taylor 7:32 am 12/6/2011

    I can understand the “shut up” bit, but not the Gingrich reference. Say what?

    Just attempting to express the idea of listening to the decidedly wealthy complaining about not having enough. Newt Gingrich only came to mind because he’s been in the news a bit lately.

    Link to this
  7. 7. naishd 7:34 am 12/6/2011

    Thanks for thoughts and comments, will respond in time. Cameron (comment 5): I wasn’t aware of Uhen (2010) until now, thanks for that. I’ve tried to be cautious about implying that ‘basilosaurids’ are monophyletic (likewise for ‘dorudontids’).. but the idea that B. drazindai and Basiloterus might be non-pelagicetans is pretty staggering. They sure do look basilosaur-like, and Uhen notes that this idea “is difficult to determine with certainty because they are known from one and two vertebrae, respectively”.

    Darren

    Link to this
  8. 8. David Marjanović 7:34 am 12/6/2011

    Some were badass predators: the ‘baby’ whale inside Maiacetus inuus might actually be the remains of a consumed prey item.

    Do tell!

    It took me quite a while to work out how to get to this one reliably… now through (horrors) facebook. Otherwise I had to keep googling text I remembered from the previous entries on Sci Am 3.

    Doesn’t your browser have any kind of memory function? The URL field of mine (good old IE8) is a drop-down menu, and Tet Zoo is there. When I browse so much in a day that it drops out of there, typing “b” in the URL field triggers auto-fill-in.

    Mysticetes or baleen whales are familiar enough animals, but the fossil record shows that the oldest stem forms (the Oligocene mammalodontids) were relatively small with relatively small skulls, a heterodont dentition and a relatively short, deep rostrum. These animals may have been beluga-like generalist feeders that used suction to capture benthic animals (Fitzgerald 2009): they weren’t orca-like predators of large vertebrates as sometimes intimated.

    Not even Janjucetus? :-(

    Really, whatever its astralagus is doing, it doesn’t look much like an antelope. More like a solenodon or something.

    Look at the other end of the astragalus. There are two ankle joints on top of each other, like in artiodactyls and nothing else.

    Link to this
  9. 9. naishd 7:35 am 12/6/2011

    Chris (comment 6): anyone who refers to me as “decidedly wealthy” surely has an excellent sense of humour.

    Darren

    Link to this
  10. 10. kattatogaru 8:38 am 12/6/2011

    ….surely wealthy in the spiritual sense of having many ‘followers’ rather than in the dull sense of owning lots of matter. Eye of the needle stuff.

    Link to this
  11. 11. farandfew 9:16 am 12/6/2011

    @David M
    sorry; what I meant was that, despite the astralagus being artiodactyl-like, the animal as a whole doesn’t look much like a modern artiodactyl.
    …Not that I’m questioning its phylogenetic placement, just speculating about its ecology.

    Link to this
  12. 12. naishd 10:45 am 12/6/2011

    Some quick responses…

    Firstly, dammit, I really wish I’d known about Uhen’s 2010 paper – it’s a very good review AND IT’S OPENLY ACCESSIBLE.

    David (comment 8): on (some) mammalodontids not being orca-like predators, Fitzgerald (2009) includes a substantial discussion of this subject, concluding with…

    “Although facultative raptorial sarcophagy cannot yet be ruled out, the novel morphology of Mammalodon is consistent with specialization for suction feeding. Independent evidence from the dentition, rostrum, cranium, mandible, and sternum suggests that this may be the most parsimonious interpretation of the feeding apparatus. There is some evidence to suggest that Mammalodon was a benthic suction feeder (Fig. 45), although not as specialized for this feeding mode as the walrus and Odobenocetops. An arguably more appropriate analogue is the extant beluga whale Delphinapterus leucas, which captures pelagic prey as well as benthic organisms using suction (Brodie, 1989; Stewart & Stewart, 1989). Analysis of dental microwear represents an opportunity to test this hypothesis, although such a project is beyond the scope of this paper.” (p. 81).

    However, on Janjucetus, Fitzgerald states…

    “Further, Janjucetus was perhaps a sarcophagous
    raptorial feeder (Fitzgerald, 2006): increased depth to the rostrum in this taxon is probably, at least in part, a response to the vertical loading on the apex and margins of the rostrum induced when biting prey.” (p. 84).

    So.. I was wrong, and will now go and modify the text.

    Darren

    Link to this
  13. 13. naishd 10:54 am 12/6/2011

    More responses…

    The idea that the ‘baby’ inside Maiacetus might not be a baby but a prey item comes from a comment that Hans Thewissen left on the Gingerich et al PLoS ONE paper. It’s titled ‘Maiacetus: displaced fetus or last meal?’.

    farandfew (comment 11): sure, pakicetids weren’t hoofed like modern artiodactyls, but the modern animals they most resembled might have been chevrotains – some of which (Hyemoschus aquaticus) are excellent swimmers, divers and bottom-walkers. But, as usual with fossil forms, pakicetids weren’t quite like any modern forms.

    Darren

    Link to this
  14. 14. Cameron McCormick 12:18 pm 12/6/2011

    but the idea that B. drazindai and Basiloterus might be non-pelagicetans is pretty staggering. They sure do look basilosaur-like

    Geisler et al. (2005) notes that vertebrae referred to Eocetus schweinfurthi were used to assign Eocetus wardii to its genus… however the vertebrae referred to E. schweinfurthi were subsequently referred to Basilosaurus drazindae… and “E.wardii has some basilosaurine-like traits (“anteroposterior diameter of the neural spine is greater than in any known protocetid and is more similar to those of basilosaurids, as is the broad, fanshaped scapula”) but is placed (just) outside Pelagiceti in a clade with E. schweinfurthi. This is giving me a headache…

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  15. 15. keesey@gmail.com 1:22 pm 12/6/2011

    [on Eschrichtius robustus] “Originally described as a fossil form from England, it was later discovered alive along the coasts of the north Pacific.”

    Wow, didn’t know that!

    “so far as I know, no-one has suggested that the term Cetacea be restricted to the crown”

    From the current draft of the PhyloCode:

    Recommendation 10.1B. The name that is more commonly used than any other name to refer to (e.g., discuss or describe) a particular crown clade should generally be defined as applying to that crown clade, even if the name is commonly considered to apply to a clade that includes extinct taxa outside of the crown….

    Note 10.1B.1. In older works and in works dealing only with extant organisms, names have sometimes been used as if they apply to particular crown clades, though it is unclear whether the author considered the name to apply to the crown or to a more inclusive clade (i.e., including some or all of the stem). In such cases, the name may be interpreted as applying to the crown for the purpose of this recommendation.”

    Thus, not only does the PhyloCode recommend using “Cetacea” for a crown group, but “Mysticeti” and “Odontoceti” as well.

    Note that, if you do insist on using “Neoceti” for the crown group, the stem group should probably be “stem-neocetes”. (Although “stem-cetaceans” is at least unambiguous.)

    One last nomenclatural note: I never understood why the original name, “Cete“, was abandoned. (This would also be available for the crown group.)

    Link to this
  16. 16. naishd 1:50 pm 12/6/2011

    Grey whale discovery and naming: the living animal was described as Rhachianectes glaucus by Cope in 1869, and not until the 1950s was it properly appreciated that this was the same animal as the Swedish fossil form Eschrichtius robustus, originally named Balaenoptera robusta by Lilljeborg in 1861. This fossil form was reported from England too, but I erred in saying that it was initially described from there. It’s also been often suggested that the New England ‘scrag whale’ – named Balaena gibbosa by Erxleben in 1777 – might have been based on grey whale descriptions. I’m resisting the temptation to dig out my copy of Hershkovitz (1966). As usual, the nomenclatural history here is a confusing mess.

    Cete: this name has been used for the proposed clade that includes Cetacea (sensu lato) and some ostensible relatives, like Andrewsarchus.

    Darren

    Link to this
  17. 17. John Harshman 3:19 pm 12/6/2011

    Hey, why no discussion of hippos and/or anthracotheres?

    And I know I could look this up, but how many “mesonychians” have known astragali, and what do they look like? Does Andrewsarchus?

    Link to this
  18. 18. Ranjit Suresh 6:03 pm 12/6/2011

    Although you were only dealing with sexual maturity in Balaenopterids and not the right whale lineage, supposedly the long-lived bowheads don’t reach sexual maturity until 20. So they may have the most delayed sexual maturity in mammals.

    Link to this
  19. 19. TimWil 8:29 pm 12/6/2011

    Nice work, once again Darren.

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  20. 20. Andreas Johansson 1:23 am 12/7/2011

    Andrewsarchus is just an (effing big) skull, isn’t it?

    Link to this
  21. 21. Dartian 2:06 am 12/7/2011

    Darren:
    the discovery of a live individual in the eastern Mediterranean Sea

    It didn’t stay in the eastern Mediterranean; on 30 May 2010, twenty-two days after it was seen in Israeli waters, the same individual was sighted off the coast of northeastern Spain, seemingly in good condition and swimming southwards (Scheinin et al., 2011). I don’t know if this whale was ever seen after that.

    Reference:
    Scheinin, A.P., Kerem, D., MacLeod, C.D., Gazo, M., Chicote, C.A. & Castellote, M. 2011. Gray whale (Eschrichtius robustus) in the Mediterranean Sea: anomalous event or early sign of climate-driven distribution change? Marine Biodiversity Records 4(e28), 1-5.

    Christopher:
    Newt Gingrich only came to mind because he’s been in the news a bit lately.

    Hmm, I thought you were referring to Philip Gingerich (who is a bona fide authority on cetacean evolution, and whom Darren cites in this article).

    Link to this
  22. 22. Allen Hazen 2:26 am 12/7/2011

    Now look what you’ve done!
    When I read your “so far as I know, no-one has suggested that the term Cetacea be restricted to the crown,” my immediate thought was “Oh-oh, somebody like Ken Kesey is going to see this!”

    (I think this– summary overview of the whole clade(*) with classified links to relevant earlier posts– is a great idea! Thanks, Darren: I know it will produce at least some hits, since I’ll use it to revisit some of your old posts.)
    (*) “the whole clade”: All organisms more closely related to Balaenoptera or Delphinus than to Mesonychus, Hippopotamus, Sus, Camelus or Bos. Which, Phylocode recommendations notwithstanding, seems, extensionally, to be pretty much what most authors have in mind when they write “Cetacea”

    Link to this
  23. 23. naishd 4:09 am 12/7/2011

    On that wayward Grey whale seen off Israel, and then Spain… while checking out-of-place ‘Grey whale’ records, I discovered a 1948 record from Sri Lanka. It’s been generally thought more recently that this was a misidentified balaenopterid… but was it?

    Darren

    Link to this
  24. 24. Dartian 5:35 am 12/7/2011

    Darren:
    while checking out-of-place ‘Grey whale’ records, I discovered a 1948 record from Sri Lanka

    Whoa! Details, please!

    Link to this
  25. 25. David Marjanović 7:46 am 12/7/2011

    The idea that the ‘baby’ inside Maiacetus might not be a baby but a prey item comes from a comment that Hans Thewissen left on the Gingerich et al PLoS ONE paper. It’s titled ‘Maiacetus: displaced fetus or last meal?’.

    Ah. That comment also says it could just as well be a fetus displaced by putrefaction gases and scavenged by sharks.

    And I know I could look this up, but how many “mesonychians” have known astragali, and what do they look like?

    Several do; they’re plesiomorphic.

    Does Andrewsarchus?

    The head, the whole head, and nothing but the head.

    Link to this
  26. 26. keesey@gmail.com 9:29 am 12/7/2011

    “All organisms more closely related to Balaenoptera or Delphinus than to Mesonychus, Hippopotamus, Sus, Camelus or Bos. Which, Phylocode recommendations notwithstanding, seems, extensionally, to be pretty much what most authors have in mind when they write “Cetacea””

    What an odd assertion. I’m sure most marine biologists have nothing like Ambulocetus (to say nothing of Indohyus) in mind when they say “cetacean”.

    Remove Mesonychus as a mandatory exclusive specifier and you have what might be called “Pan-Cetacea” (or at least “pan-Cetacea”) under the PhyloCode.

    Link to this
  27. 27. John Harshman 10:50 am 12/7/2011

    “Ken Kesey” = Mike Keesey? Who knew?

    So, if mesonychians are to be the sister group of whales, we need a serious reversal in the astragalus. Presumably, other characters render this parsimonious in morphological analyses. Andrewsarchus, possibly not a mesonychian at all, is saved from this problem by lack of data.

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  28. 28. keesey@gmail.com 12:35 pm 12/7/2011

    Ken Kesey is no more; I still am.

    (Given how many times the spelling of my surname has changed, and that we both descend from Pennsylvania German ancestors, it’s possible we’re distant cousins. I don’t know the precise link, though.)

    Link to this
  29. 29. Halbred 2:12 pm 12/7/2011

    On the subject of _Janjucetus_, I remember reading earlier this year a new paper by Fitzgerald in which he added that taxon to a list of suction-feeding critters.

    Actually, a quick search reveals that Ed Yong did a post on this very topic (here).

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  30. 30. Allen Hazen 2:29 pm 12/7/2011

    Mike Keesey–
    Apologies for misremembering your name!
    And thanks for comment on “Pan-Cetacea”. (Why should “Mesonychus” not be used as external specifier? (For that matter, have I misremembered ANOTHER name? is the type genus for Mesonychia Mesonyx?))
    As for what authors “have in mind”, that’s why I said “extensionally”: they may not be thinking of Ambulocetus, but their practice suggests a willingness to include all Pan-Cetaceans under “Cetacea.”

    Link to this
  31. 31. Andreas Johansson 3:39 pm 12/7/2011

    The original mesonychian is indeed Mesonyx.

    Link to this
  32. 32. David Marjanović 8:12 am 12/8/2011

    Why should “Mesonychus” not be used as external specifier?

    For Pan-Cetacea? Because it’s extinct.

    Link to this
  33. 33. keesey@gmail.com 9:54 am 12/8/2011

    What David said — the “Pan-” prefix must precede a crown group name, and the resulting “panbranch name” must refer to the corresponding total group. (I.e., the initial ancestor of the crown group that is not also ancestral to anything else extant, and all descendants thereof.)

    Here’s an example of a recent paper using “Cetacea” for the crown group, contra your assumption: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007062

    (Although note that they use “Cetaceamorpha” for the total group.)

    Link to this
  34. 34. Allen Hazen 6:45 pm 12/8/2011

    David, Mike–
    Thanks! I think I see the logic: if the extinct external specifier did any work, it would mean that the clade excluding it ISN’T the total clade corresponding to the crown group.

    (I still think the preference given to crown groups is a mistake, but since we’ve discussed this in the past I don’t think it’s worth going over again: I certainly don’t have any NEW arguments! Question, though: can one, given the official definitions, talk about the “stem group” of a group with no extant crown? Certainly it seems natural enough to do so in some contexts: suppose I wanted to say of some early dinosaur that it was closer to the ancestry of Sauropods than to any accepted Theropods, but didn’t want to say it was descended from the last common ancestor of Diplodocids, Brachiosaurs and Titanosaurs, it seems to me I might say it was a “stem Sauropod,” and I think I would probably be understood if I did so. Would this be correct, or just a literally incorrect metaphorical use of “stem”?)

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  35. 35. David Marjanović 8:26 am 12/9/2011

    Question, though: can one, given the official definitions, talk about the “stem group” of a group with no extant crown?

    No. Clades without a crown can’t have a stem.

    Certainly it seems natural enough to do so in some contexts: suppose I wanted to say of some early dinosaur that it was closer to the ancestry of Sauropods than to any accepted Theropods, but didn’t want to say it was descended from the last common ancestor of Diplodocids, Brachiosaurs and Titanosaurs, it seems to me I might say it was a “stem Sauropod,” and I think I would probably be understood if I did so.

    Absolutely not. It would be understood that you mean “closer to sauropods than to some other big group, probably theropods”, but it would not be understood what you mean by the implied crown: Sauropoda itself (so you should have said “non-sauropodan sauropodomorph”)? Perhaps Eusauropoda? Perhaps Neosauropoda (as it turns out you do)? Perhaps Titanosauria? Perhaps something else?

    Olivier Rieppel keeps talking about “stem-sauropterygians” in his papers. It took me years to figure out that the implied “crown” is the smallest clade that contains all Jurassic & Cretaceous sauropterygians (so that “stem-sauropterygian” is almost synonymous with “Triassic sauropterygian”… or rather “Triassic euryapsid” outside of Rieppel’s usage of the name Sauropterygia).

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  36. 36. keesey@gmail.com 4:46 pm 12/9/2011

    No, you can’t.

    All sauropods are stem-avians.

    (Now, if you travelled back in time to the Early Cretaceous, then you might be able to use it the way you say, although it ought to be “stem-neosauropod”, not “stem-sauropod”. But if you travelled to the Late Cretaceous, the crown group would be smaller, more like Titanosauria. And if you travelled to the Late Jurassic it would be larger, more like Sauropoda. See how complex this gets? That’s why the terminology is limited to the present, or something like it.)

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  37. 37. accipiter 8:48 am 12/10/2011

    wait no; all theropods are stem-avians, then sauropodomorphs are from only the sister-groups of theropods (and the last common ancestor of sauropods and theropods whould be stem-saurischian i think) am i wrong?

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  38. 38. accipiter 9:13 am 12/10/2011

    about the noisy properties of the fin-whale jaws
    (link:http://scienceblogs.com/tetrapodzoology/2009/03/rorquals_part_iii.php)
    i think i heard something similar on a blue whale:

    i was free-diving with blue whales off san diego and at one point one that was swimming right towards me rolled on its side and looked at me, and i heard a loud distinct noise as it passed by me. it was a a little like an old door creaking, or a burping but much slower frequency and much deeper-pitched (i could clearly feel it resonates in my chest). i know mysticetes have no forward vision whatsoever so i thought this whale was just growling at me because he was startled to suddently find me right next to him (hey, they’re mammals after all!) and i was barely 4m away from his eye.
    but after reading your old article i wonder if it might not have been this jaw noise… (the water was murky and they were definitely foraging in the area where we dived with them); but when i heard the noise its pouch was empty and the jaws were in normal position (not roteted sideways nor extended). hum… if anybody know more i’d like to know when exactly does this noise happens (is it when the jaws are being extended, or when returning at normal position?)

    incidentally , i was filming and have the movie of it if you are interested to see it. but sadly the relevant noice is barely audible in the movie (something to do whith my camera housing i guess) but as i said before it was loud in real life…
    in the old article darren said that he’d like to know if this noise existed in other whales but i thought i’d poste this here as it’s a ‘clearing house’ article…
    otherwise great stuff as always, darren!

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  39. 39. keesey@gmail.com 12:29 pm 12/10/2011

    @accipiter, a stem group is a total group minus the corresponding crown group. Aves (sensu stricto) is a crown group. One definition is, “the final common ancestor of ostriches, great tinamous, and Andean condors, and all descendants of that ancestor.” The corresponding total group, which variously goes under the name Avemetatarsalia or Panaves (and may be named “Pan-Aves” under the PhyloCode), is defined as, “the initial ancestor of Aves which is not also ancestral to any extant non-avian, and all descendants of that ancestor.”

    Thus the avian total group (“Pan-Aves“) includes anything sharing more ancestry with extant birds than with extant crocodylians, including all dinosaurs and pterosaurs, plus more basal forms. A stem-avian is any non-avian member of the avian total group. Thus, stem-avians include Scleromochlus, Marasuchus, Pterosauria, Silesauridae, Ornithischia, Eoraptor, Herrerasauridae, Sauropodomorpha, Coelophysoidea, Ceratosauria, Megalosauroidea, Carnosauria, Tyrannosauroidea, Ornithomimosauria, Therizinosauria, Alvarezsauroidea, Oviraptorosauria, Scansoriopterygidea, Deinonychosauria, Archaeopterygidae, Omnivoropterygidae, Confuciusornithidae, Enantiornithes, Patagopterygidae, Songlingornithidae, Hesperornithes, Ichthyornithes, and Ambiortidae.

    Theropoda includes both avians and some (but not all) stem-avians.

    Link to this
  40. 40. accipiter 8:31 am 12/11/2011

    ah ok thanks so THAT’s where the name pan-aves comes from. i aleready knew of this group but i prefered the name avemetatarsalia cause pan-aves (“all birds”) seemed to me like just a very contrived way of underlining that birds are part of archosauria(peraps as a responce to all those who still think otherwise for some retarded reasons)… but i prefered avemetatarsalia since even though birds are their closest living relatives one whould still hardly call “birds” critters like pterosaurs or marasuchus.
    but if this is what actually corresponds to bird total-group then panaves makes more sence indeed; it was just me not understanding the proper definition of a stem-group.
    though what does “initial ancestor” means exactly?:
    because if you define panaves as:
    “the initial ancestor of Aves which is not also ancestral to any extant non-avian, and all descendants of that ancestor.”

    isn’t this synonym to aves? for example saurpods are non-avians, and they clearly have a common ancestor with aves (the last common ancestor of sauropods and theropods), same for carnosauria, hesperornithes, ect all the way until we get back to aves themselves basically??

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  41. 41. John Harshman 10:43 am 12/11/2011

    if you define panaves as:
    “the initial ancestor of Aves which is not also ancestral to any extant non-avian, and all descendants of that ancestor.”

    isn’t this synonym to aves?

    No. Note “extant” in that definition. The common ancestor of sauropods and secretary birds is not also ancestral to any other extant non-avian. So sauropods are within Panaves. The initial (earliest) ancestor of Aves that is not also ancestral to any extant non-avian is whatever came immediately after the split between the ancestors of birds and the ancestors of crocodylians. A clearer definition of Panaves would in fact be a standard branch-based definition, say “all taxa more closely related to Passer domesticus than to Crocodylus niloticus or Testudo hermanni“, assuming that we are correct in identifying all candidates for the extant sister group of Aves.

    Link to this
  42. 42. David Marjanović 11:31 am 12/11/2011

    “Extant” has somehow acquired the meaning “not dead”.

    Link to this
  43. 43. keesey@gmail.com 2:38 pm 12/11/2011

    That’s the only way I’ve seen it used. (Well, more generally, “surviving”, as in “extant manuscripts”.)

    Link to this
  44. 44. keesey@gmail.com 12:21 pm 12/20/2011

    “Pan-aves (“all birds”) seemed to me like just a very contrived way of underlining that birds are part of archosauria”

    It’s not. It’s part of a proposed system whereby all named total groups would have such names. So you’d also have “Pan-Mammalia“, “Pan-Vertebrata“, “Pan-Cetacea“, “Pan-Odontoceti“, “Pan-Mysticeti“, etc.

    There was a draft of the PhyloCode that proposed this form of name as mandatory for total groups. This generated some argument, because many total groups already have clear names (e.g., most people would rather use “Synapsida” or even “Theropsida” than “Pan-Mammalia“). The current draft has a compromise, whereby existing names can in some circumstance be converted to total clade names, but the “pan-” form will always be available as an informal alternative (e.g., “pan-Mammalia” [note lack of italics]).

    “but i prefered avemetatarsalia since even though birds are their closest living relatives one whould still hardly call “birds” critters like pterosaurs or marasuchus.”

    Well, they still wouldn’t be avians, they’d be pan-avians (and stem-avians). Just like Ornithsuchus, Effigia, Postosuchus, Sphenosuchus, etc. would be pan-crocodylians (and stem-crocodylians).

    Avemetatarsalia” is a decent enough name (although wouldn’t “Ornithometatarsi” be better?), but it doesn’t tie into a general system like “Pan-Aves” does. That said, either name would be admissible under the PhyloCode.

    Link to this

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