Hesperornis walking GIF

Figure 1. Hesperornis compared to a king penguin, Atenodytes. Hesperornis has larger feet and a longer tibia. Since penguins swim with their forelimbs, they have large pectoral muscle anchors. That is not the case with Hesperornis.

Figure 1. Hesperornis compared to a king penguin, Atenodytes. The patella is blue. Hesperornis has larger feet and a longer tibia. Since penguins swim with their forelimbs, they have large pectoral muscle anchors. That is not the case with Hesperornis. Click to enlarge. Marsh 1872 thought Hesperornis could stand upright. I do too. That makes only two of us.

Hesperornis regalis
(Figs. 1,2, Late Cretaceous, Campanian, Marsh 1872, 1.8m long) was a toothed, flightless marine bird with vestigial wings and asymmetrical feet. Although not related to living loons, Hesperornis is often compared to loons, which have no teeth and retain the ability to fly. Both swim with powerful hind limbs. Hesperornis can also be compared to another flightless bird clade, the penguins, with the proviso that penguins swim with powerful forelimbs and their skeletons (Fig. 1) reflect this.

Figure 2. Click to enlarge. Hesperornis walking GIF movie. In this hypothetical scenario Hesperornis walks bipedally.

Figure 2. Click to enlarge. Hesperornis walking GIF movie. In this hypothetical scenario Hesperornis walks bipedally. Like penguins and ducks, Hesperornis does not flex its toes while walking. Nor does it take very big steps.

Wikipedia reports,
“In terms of limb length, shape of the hip bones, and position of the hip socket, Hesperornis is particularly similar to the common loon (Gavia immer), probably exhibiting a very similar manner of locomotion on land and in water. Like loons, Hesperornis were probably excellent foot-propelled divers, but ungainly on land. Like loons, the legs were probably encased inside the body wall up to the ankle, causing the feet to jut out to the sides near the tail. This would have prevented them from bringing the legs underneath the body to stand, or under the center of gravity to walk (Reynaud 2006). Instead, they likely moved on land by pushing themselves along on their bellies, like modern [loons].”

It was not difficult
to animate a bipedal Hesperornis (Fig. 2). It appears fully capable of doing so penguin-style. But the comparison to loons is indeed compelling.

Loons are ungainly
on the beach. See a YouTube video here. Yes, it does look wounded, unable to walk like a normal bird. It would probably fly if it was in a hurry. Hesperornis shares many traits by convergence with loons, but, if anything, loon hind limbs are more extreme in their proportions, including a proportionately larger projecting patella (Figs. 3, 4).

Just added after publication: The axis of the acetabulum is further foreword in Hesperornis, at the 51% mark on the torso (measured from the posterior pelvis) versus the 43% mark on the loon. That big butt makes Hesperornis less top heavy.

Figure 3. Loon skeleton with femur (yellow) and tibia/patella (green) highlighted. In this mount the center of gravity is in front of the toes, which makes this an untenable mount, unless the loon is floating on water.

Figure 3. Loon skeleton with femur (yellow) and tibia/patella (green) highlighted. In this mount the center of gravity is in front of the toes, which makes this an untenable mount, unless the loon is floating on water.

The loon femur is a little shorter and the patella is a little larger
(Figs. 3, 4) than on Hesperornis (Figs. 1,2). It’s up to our imaginations whether or not that would enable a more penguin-like locomotion in Hesperornis. Note that penguins do have a patella (knee bone) but it does not extend above the femur as it does in Hesperornis and loons.

Figure 4. Loon femur and tibia/patella. These proportions are more extreme than those found in Hesperornis.

Figure 4. Loon femur and tibia/patella. These proportions are more extreme than those found in Hesperornis. Note the right angle femoral head, as in most birds, but then look at the skeleton (Fig. 3) in which the femora are held laterally, unlike more birds and dinosaurs.

Nat Geo
and Andy Farke report on a bone growth and possible migration study (Wilson and Chin 2014) of Hesperornis here.

According to Marsh:
“The clavicles are separate, but meet on the median line, as in some very young existing birds.The coracoids are short, and much expanded where they join the sternum. The latter has no distinct manubrium, and is entirely without a keel. The wings were represented by the humerus only, which is long and slender, and without any trace of articulation at its distal end.”  

Various authors
believe the humerus would have been hidden beneath the skin and appressed to the ribs. As is typical for Kansas fossils, Hesperornis specimens are typically crushed flat. In the large reptile tree Hesperornis nests with its volant contemporary, Ichthyornis.

References
Marsh OC 1872. Discovery of a remarkable fossil bird. American Journal of Science, Series 3, 3(13): 56-57.
Marsh OC 1872. Preliminary description of Hesperornis regalis, with notices of four other new species of Cretaceous birds. American Journal of Science 3(17):360-365.
Marsh, OC 1880. Odontornithes, a Monograph on the Extinct Toothed Birds of North America. Government Printing Office, Washington DC.
Reynaud F 2006. Hind limb and pelvis proportions of Hesperornis regalis: A comparison with extant diving birds. Journal of Vertebrate Paleontology 26 (3): 115A. doi:10.1080/02724634.2006.10010069.
Wilson L. and Chin K 2014. Comparative osteohistology of Hesperornis with reference to pygoscelid penguins: the effects of climate and behaviour on avian bone microstructure. Royal Society Open Science. 1: 140245. doi: 10.1098/rsos.140245

OceansofKansas/Hesperornis

wiki/Hesperornis

Advertisements

7 thoughts on “Hesperornis walking GIF

  1. David: check out also skeletons of great auk and common murre. Huge pectoral muscles in both and acetabulum set far back. Yet both walk[ed] upright. By comparison, Hesperornis [with tiny breast, and as you say, a big butt] would easily stand upright.

    PS: A friend in grad school did a thesis on biomechanics of alcids, and it was my job to force the murres to walk the plank in front of his movie camera.. Upright, little steps. Also got to see great auk skeletons from museum collections.

    • Please try and use decent English. You’re SAYING David’s GIF animation proves something. Even going by your meaning, your statement, since there are no qualifications, proves nothing at all. I have issues with David’s Hesperornis, but none of my issues have anything to do with his thesis. What, specifically, are YOUR objections? Can you prove he is wrong? Saying a majority says otherwise means little in the face of similarly proportioned modern birds that do walk.

      • English is not my native language. So this isn´t my problem.

        I can make and bidimensional animation for a elephant walking in two legs too. And It don´t proves that this is main way of locomotion of this animal. The same happens with the .gif animation of Hesperornis.
        There isn´t a Negative proof. Thats the same question for UFOS, or Ghosts,
        ” Prove he is wrong” bla bla, Peters is the man that must prove his hipothesis, with more than a PHOTOSHOP file.

        The fact that you idealizes the work of David Peters don´t make it real too.
        Peters is not Galileo, is not the leader of a science revolution. It´s only a graphic designer with much free time.

        The issue with Hesperornis would be resolved with biomechanical studies, not with a gif file. And if Hesperornis can walk, this isn´t a proof that strengthens DGS or PILS or any other “discover” that Peters can do in the future.

        Well, I will visit this website anymote time again. Peters always delete my comment as SPAM after all, so I believe that we will met again Bryan Riolo, the Peters bulldog. ¿ Or Corgy maybe? No matters, this nonsense will finish someday.

      • You make claims for which you have no proof of any kind at all. I idealize nobody’s work, except maybe AS artwork. Please make fewer assumptions vis-a-vis me. IF David’s hesperornis GIF is wrong, please show me WHERE it is wrong. I myself see basic errors in kinetics, but none of those errors disqualify his thoughts on this subject.

        YOUR thesis here seems to be: it is wrong because you and others do not like his methodology. It is wrong because David Peters said it. THAT IS NOT SCIENCE, IT IS GOOFBALL POLITICS!

        What if David said Struthio is a bird? Is Struthio no longer a bird because David Peters claims it is one? Is that what science has come to? You seem to think so. If so, then we have nothing more to discuss.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s