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Creodonts
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" Reconstructed on the basis of a single, enormous skul—discovered by the famous fossil-hunter Roy Chapman Andrews during an expedition to the Gobi Deser.
Andrewsarchus was a genus of mammal that lived during the middle Eocene epoch in what is now Inner Mongolia, China. Only one species is usually recognized, A. mongoliensis, known from a single skull of great size discovered in 1923 during the expeditions to central Asia by the American Museum of Natural History(AMNH). Generally classified as a mesonychidsince its original description, most recent studies classify it as an artiodactyl, in one study specifically, as a member of the clade Cetancodontamorpha, closely related to entelodonts, hippos and whales. "
A life sized model of an Andrewsarchus at the Chicago Field Museum.
Credit to John Janssen  *This image is copyright of its original author  *This image is copyright of its original author
A question came to my mind. Were Megistotherium and simbakubwa's limbs as useless as a hyena? Or was it useful like a bear-dog? @tigerluver @GuateGojira
(Picture 1 Hyaenodonts legs : Megistotherium - Simbakubwa - Hyainailouros. The first 2 belong to Megistotherium) (Pic 2 Amphicyon claw)  *This image is copyright of its original author  *This image is copyright of its original author
Are these real for Megistotherium? If so, this beast weighs around 1100 kg. 170 cm at the shoulder and a skull of about 737 mm! @GuateGojira @tigerluver :
 *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
 (02-23-2022, 06:26 PM)tostwear Wrote: Are these real for Megistotherium? If so, this beast weighs around 1100 kg. 170 cm at the shoulder and a skull of about 737 mm! @GuateGojira @tigerluver : Looks like years ago I look into its size and seems like 1 metric ton or more is reasonable for this giant by this post. We are missing most of the skeleton of the species so it's hard to get an accurate estimate but based on the humeral width, those bones were supporting a lot of weight. Do you have the sources for the photos? (02-23-2022, 06:20 PM)tostwear Wrote: A question came to my mind. Were Megistotherium and simbakubwa's limbs as useless as a hyena? Or was it useful like a bear-dog? @tigerluver @GuateGojira We can't comment on Megistotherium because we don't have complete long bones. From this old post, there is no complete long bone of Simbakubwa if I remember correctly but the humerus looks quite stout:  *This image is copyright of its original author Compared to a brown bear:  *This image is copyright of its original author
(02-26-2022, 01:37 AM)tigerluver Wrote:(02-23-2022, 06:26 PM)tostwear Wrote: Are these real for Megistotherium? If so, this beast weighs around 1100 kg. 170 cm at the shoulder and a skull of about 737 mm! @GuateGojira @tigerluver : Source of the photos (Photos were mixed in the previous pages.) : https://forum.zoologist.ru/viewtopic.php?id=313&p=118 (02-26-2022, 01:37 AM)tigerluver Wrote:(02-23-2022, 06:26 PM)tostwear Wrote: Are these real for Megistotherium? If so, this beast weighs around 1100 kg. 170 cm at the shoulder and a skull of about 737 mm! @GuateGojira @tigerluver : And a broken part of the mandible of megistotherium:  *This image is copyright of its original author
@tigerluver It makes more sense to look at its very close relative, 'Hyainailouros Sulzeri', rather than Hyaenodon. The hind claw of Hyainailourus is nearly identical to the hind claw of an amphicyon. So it's very possible to have the same level of functionality. (this also applies to megistotherium). Here's the Hyainailouros hind claw and Amphicyon hind claw:
*This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author (02-26-2022, 01:37 AM)tigerluver Wrote:(02-23-2022, 06:26 PM)tostwear Wrote: Are these real for Megistotherium? If so, this beast weighs around 1100 kg. 170 cm at the shoulder and a skull of about 737 mm! @GuateGojira @tigerluver : That'd be an overestimation... "500 kg is likely the max. Most people do not get that the mass estimates from Sorkin (2008) are not meant to be the actual mass of the animals. The mass from Sorkin (2008) represents the upper limit of an animal imposed by its 'biomechanical constraint'. This means that it is not possible for Meg to be over 500 kg otherwise it would not be able to function properly. However, that does not mean that 500 kg is the actual/accurate weight. However, beside Sorkin (2008), i'm unable to find any official mass estimates for Meg. As long as it does not go above 500 kg according to Sorkin (2008) I have done some armature estimates on my own by using the head/head-body length ratio of H.horridus and H.crucians in Valkenburgh (1987) in order to get the head-body length of Meg. Then i use the equation from Valkenburgh (1987) to estimate the body mass based on head-body length. I thought the 66.4 cm skull length figure was Greatest skull length, while in fact it's actually condylobasal (premaxilla - occipital condyle). I ended up underestimating the mass a bit. Adjusting for this, my new figure for body mass is 340 - 460 kg with a mean of 400 kg, which is actually surprisingly consistent with that of Sorkin 2008 at 500 kg (which is obtained through isometric scaling of a Tiger's humerus). Sorkin's method is imo not unreasonable like what i said before because Hyaenodontid usually do not have really long legs (thus it's less likely to overestimate if scaled by limb length). Savage (1973) (page 503) pointed out that the distal width of the humerus of Megistotherium is comparable in size to that of large Brown bears. Anderson (2004) pointed out that the surface of distal humerus trochlea is strongly correlated with body mass. Obvious, distal humerus width is not the same as distal humerus trochlea but there are still some correlations here. In conclusion, it seems pretty reasonable that Megistotherium would be comparable in size to those of modern big Bears (Kodiak, Polar)." |
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