|
Megalodon not as big as we once thought!
|
 (08-14-2020, 11:12 PM)Shadow Wrote:(08-14-2020, 04:41 PM)BorneanTiger Wrote:(08-13-2020, 04:28 AM)Shadow Wrote:(08-09-2020, 10:53 AM)BorneanTiger Wrote:(08-04-2020, 08:57 AM)Shadow Wrote:(08-04-2020, 08:04 AM)scilover Wrote:(10-09-2019, 11:12 PM)genao87 Wrote: new study on Meg. it calculated its frontal teeth to give a more accurate size....so we have it at 14-15 meters at maximum with 15 meters being extremely rare. I think a POD of Orcas can seriously hurt Meg now. Leviathan Melville Sperm Whale now will and can defeat it. Average size is not talked about but I am guessing around maybe 12-13. Do you know that even great white sharks have a social structure, and kill (juvenile) humpback whales? https://www.naturalhistorymag.com/htmlsi...ature.html, https://web.archive.org/web/201305150612...le-killers Because sharks like the great white can be social, who can be sure that Megalodon couldn't form social structures that would have given orcas a headache, like how great whites can give smaller dolphins a headache? John Hargrove with an orca, credit: Palgrave Macmillan Trade Whatever the true size of Megalodon, no orca has jaws this big, so imagine a pod of orcas coming across of group of large sharks with such monstrous jaws (credit: the National Geographic)! Livyatan melvillei for comparison, credit: Levi2207  (08-19-2020, 11:29 AM)BorneanTiger Wrote: Do you know that even great white sharks have a social structure, and kill (juvenile) humpback whales? https://www.naturalhistorymag.com/htmlsi...ature.html, https://web.archive.org/web/201305150612...le-killers First: If the white shark had a social structure is complete irrelevant as the Carcharocles (Otodus) megalodon was not a white shark, was not even close! It is time to change this wrong idea that "megalodon" was just a big white shark. They are closer to other shark species and more modern reconstructions are changing this incorrect idea. Second: That picture of the orca do not represent the biggest skull reported, which may surpass the 1 meter of length. However you are comparing animals that do not lived int he same time and with the same size. In fact, it is important to know that the "orcas" that lived in that time were much smaller Orcinus citoniensis, about the size of modern false killer whales (skull of around 60 cm), so no orcas of 9 meters in those days. Third: This is a much better comparison of the skull of Livyatan and C. (O.) megalodon:  *This image is copyright of its original author Check the size of the skull of the cetacean:  *This image is copyright of its original author The angle of the pictures is very deceptive, we must take care of what we use. The idea that the "megalodon" was a giant white shark that hunted huge sperm whales (that do not even existed in those days, by the way) and that fought with pack of large orcas is a MYTH created long time ago and draged by "fans" in the web. The true is that must of the whales in that time were very small, at about 6 meters in length, that most of the C. (o.) megalodon were about 10 meters in length (from tip of snouth to tip of the tail fin) and where NOT giant white sharks, also were not very fast swimers. And finally the orcas that lived in those days were small of about the same of the modern false killer whale and with simillar diets. The Livyatan melvillei was a true competitor of the giant shark, but competitor do not mean that they run against each other at every moment, that is also a childlist idea of the "fans" at the web. (08-25-2020, 06:46 AM)GuateGojira Wrote:(08-19-2020, 11:29 AM)BorneanTiger Wrote: Do you know that even great white sharks have a social structure, and kill (juvenile) humpback whales? https://www.naturalhistorymag.com/htmlsi...ature.html, https://web.archive.org/web/201305150612...le-killers Neither did I say that Megalodon was a great white (or even a close relative for that matter), nor that it necessarily hunted Livyatan melvillei or huge sperm whales, and it's not like the GW is the only shark that may socialise (including when hunting): (08-25-2020, 01:27 PM)BorneanTiger Wrote: Neither did I say that Megalodon was a great white (or even a close relative for that matter), nor that it necessarily hunted Livyatan melvillei or huge sperm whales, and it's not like the GW is the only shark that may socialise (including when hunting): The fact that you continue associating the white shark with the "megalodon" in your examples suggest that. Other thing, these congregations of sharks are exceptions to the rule, most of the sharks are solitary or congregate only when a food source is big enough. So there is no evidence of gregary behaviour for C. (o.) megalodon at any point. (08-25-2020, 08:16 PM)GuateGojira Wrote:(08-25-2020, 01:27 PM)BorneanTiger Wrote: Neither did I say that Megalodon was a great white (or even a close relative for that matter), nor that it necessarily hunted Livyatan melvillei or huge sperm whales, and it's not like the GW is the only shark that may socialise (including when hunting): No, people use modern examples (like lions) to imagine what prehistoric animals (like Smilodon populator) were like, but that doesn't mean that they are saying that sabretooths were prehistoric versions of lions, or even closely related to modern big cats, so just because I have been using modern sharks (like the great white and hammerhead) to imagine what things were like for Megalodon, that shouldn't be considered to mean any close relationship: An imagined fight between sabertooths, using the modern example of the lion: In fact, you've done something similar yourself, using the outline of the modern great white shark to imagine what the prehistoric Megalodon looked like, but that doesn't mean that you were saying that they were closely related! *This image is copyright of its original author
(08-25-2020, 09:48 PM)BorneanTiger Wrote: n fact, you've done something similar yourself, using the outline of the modern great white shark to imagine what the prehistoric Megalodon looked like, but that doesn't mean that you were saying that they were closely related!The image may look like white shark but is not the same, as we can erase the outline and leave only the jaws. By the way, even then we can see that the cetacean has a bigger bite than the shark. (08-25-2020, 11:46 PM)GuateGojira Wrote:(08-25-2020, 09:48 PM)BorneanTiger Wrote: n fact, you've done something similar yourself, using the outline of the modern great white shark to imagine what the prehistoric Megalodon looked like, but that doesn't mean that you were saying that they were closely related!The image may look like white shark but is not the same, as we can erase the outline and leave only the jaws. By the way, even then we can see that the cetacean has a bigger bite than the shark. Yes, but either way, it's not unusual to use modern creatures to imagine or reconstruct the looks, behaviour or ecology of prehistoric animals, even if in a minor way. For instance, if sharks didn't exist today, then we wouldn't have this reconstruction, would we? "My New Megalodon" by Harry the Fox: "Megalodon Size" – Part 1: "Megalodon Size" – Part 2: (08-27-2020, 08:59 PM)BorneanTiger Wrote: Yes, but either way, it's not unusual to use modern creatures to imagine or reconstruct the looks, behaviour or ecology of prehistoric animals, even if in a minor way. For instance, if sharks didn't exist today, then we wouldn't have this reconstruction, would we? Credit: Harry the Fox Good images, but the information is now outdated. New information shows that these sharks were not close to the white shark, but much different, not only in the body itseld but also in the tail form. It is known that sharks normally do not leave fossils of the body because they do not have bones, but in some cases there are exceptional specimens that leave very good fossils. The closer known relative of the Carcharocles (Otodus) megalodon is the Cretolamna appendiculata, a relative medium sized shark and we have one of the best fossils of this species, check this:  *This image is copyright of its original author Under this image, Paleontologist know that the "megalodon" was not a fast hunter as the white shark but a slow swimer as the modern sand tiger shark or the basking shark:  *This image is copyright of its original author  *This image is copyright of its original author These sharks have heterocercal tails, which means that the uper lobule is very elongated and measn that the can make short burst of spead but not a prolonged fast travel, like the fish that have homocercal tails (lobules about the same size) characterized for fast swimers fish like sword fish or tuna. White shark and makos are closer to the homocercal than to the heterocercal, check again the tail of Cretolamna appendiculata. Newer reconstructions must and are taking this in count, check this out:  *This image is copyright of its original author Reconstruction from "Palaeos" and Paleontologist Roberto Díaz Sibaja from 2020. However he scalated the animal at 18 m long, which is too large for the modern estimation of size (he also said that too). Compare it with the 6 m long female white shark.  *This image is copyright of its original author Art from Christopher Chávez, also from 2020. Good image but somewhat too pointed in the nose.  *This image is copyright of its original author And this one from Jaime Bran, again from 2020. Escalated at 15 meters long. As you can see, slowly but strongly, the idea of how the "megalodon" looked is changing and like the Spinosaurus, sooner or late the new form will be accepted. (09-01-2020, 06:07 AM)GuateGojira Wrote:(08-27-2020, 08:59 PM)BorneanTiger Wrote: Yes, but either way, it's not unusual to use modern creatures to imagine or reconstruct the looks, behaviour or ecology of prehistoric animals, even if in a minor way. For instance, if sharks didn't exist today, then we wouldn't have this reconstruction, would we? Credit: Harry the Fox I have discovered that it's not even as simple as that, because for instance, another prehistoric mega-toothed shark that is considered to be a close relative of Megalodon (hence considered to belong to the same genus as Megalodon) is Carochles angustidens / Otodus angustidens, and in 2001, the discovery of what was said to be the best-preserved angustidens specimen to date by two scientists, Michael D. Gottfried and Ewan Fordyce, had been presented by the team as evidence for close morphological ties with the extant great white, and so the team argued that angustidens (along with all other related megatooths, including Megalodon) should have been assigned to Carcharodon, as was done before by Louis Agassiz: https://www.tandfonline.com/doi/abs/10.1...2.0.CO%3B2 Basically, the issue of which shark is closely or distantly related to the Megalodon and other megatooths is a controversial topic, with different models of evolution giving different answers. A tooth of Carcharocles / Otodus angustidens measuring 4.25 inches (10.795 cm), found in the Edisto River of South Carolina's Lowcountry, image by user Crazy Uncle Jim (16th of August, 2007): 2 teeth belonging to another species (Carcharocles / Otodus auriculatus): USNM & PAL-537807. Credit: E. Emmons (1858), North Carolina Geological Survey Report, pages 231–234, Figures 57–58; P. Bartsch & A. R. Barwick (1941), Copeia (1): 40–41; from Craven County, North Carolina; posted by The Smithsonian (2nd of June, 2009): https://collections.si.edu/search/detail...term=shark A tooth belonging to Carcharocles / Otudus sokolovi from Dakhla (Morocco), measuring 3 inches (7.62 cm), with a feeding damage to the tip and some "lightning strikes", image by user Whodaman HD (11th of December, 2019): A chipped tooth belonging to Carcharocles / Otodus subauriculatus (also chubutensis), which was thought to have evolved into Megalodon. Dated to the Early – Middle Miocene (~ 18–15 million years ago), it had a slant height of 2.25 " (57 mm), and was found by Jayson Kowinsky (2011) in Chesapeake Bay Area (on the border of the States of Maryland, Virginia and Delaware): https://www.fossilguy.com/sites/calvert/calv_meg.htm Lingual and labial view of a lateral tooth belonging to a Megalodon, which was found by Kowinsky at Calvert Cliffs, in Maryland's portion of Chesapeake Bay. Dated to the same period as above, it had a slant height of 2 ⅜ " (60 mm): A tooth of the Megalodon with 2 teeth of the great white, by user "Broken In a Glory": (09-14-2020, 03:25 PM)BorneanTiger Wrote: I have discovered that it's not even as simple as that, because for instance, another prehistoric mega-toothed shark that is considered to be a close relative of Megalodon (hence considered to belong to the same genus as Megalodon) is Carochles angustidens / Otodus angustidens, and in 2001, the discovery of what was said to be the best-preserved angustidens specimen to date by two scientists, Michael D. Gottfried and Ewan Fordyce, had been presented by the team as evidence for close morphological ties with the extant great white, and so the team argued that angustidens (along with all other related megatooths, including Megalodon) should have been assigned to Carcharodon, as was done before by Louis Agassiz: https://www.tandfonline.com/doi/abs/10.1...2.0.CO%3B2 Did you notice that the article is from 2001? That information is now outdated and do not apply to "megalodon" anymore. Current consensus is that "megalodon" is not related at all with the modern white shark and even they tooth are very different, as we can see in your last picture. (09-15-2020, 08:07 PM)GuateGojira Wrote:(09-14-2020, 03:25 PM)BorneanTiger Wrote: I have discovered that it's not even as simple as that, because for instance, another prehistoric mega-toothed shark that is considered to be a close relative of Megalodon (hence considered to belong to the same genus as Megalodon) is Carochles angustidens / Otodus angustidens, and in 2001, the discovery of what was said to be the best-preserved angustidens specimen to date by two scientists, Michael D. Gottfried and Ewan Fordyce, had been presented by the team as evidence for close morphological ties with the extant great white, and so the team argued that angustidens (along with all other related megatooths, including Megalodon) should have been assigned to Carcharodon, as was done before by Louis Agassiz: https://www.tandfonline.com/doi/abs/10.1...2.0.CO%3B2 Though they are different, the teeth of the great white look more similar to those of C. / O. subauriculatus (chubutensis) than to those of these mako sharks (genus Isurus), and the teeth of the latter look more similar to those of a number of megatooths shown here, even though both the great white and mako are mackerel sharks (order Lamniformes) which are outside the genus Otodus, and the others are megatooths which are supposed to be in the same genus as Megalodon, that is Otodus (or formerly Carcharocles), and consensuses change over time, like about how ape-like or human-like Lucy the australopithecine was. The jaws of a shortfin mako (Isurus oxyrinchus) from the Northern Atlantic, by Didier Descouens (8th of March, 2012): The jaws of a longfin mako (Isurus paucus) from the Greater Caribbean, by D. Ross Robertson of the Smithsonian Tropical Research Institute: https://biogeodb.stri.si.edu/caribbean/e.../specie/52 (09-15-2020, 08:51 PM)BorneanTiger Wrote: Though they are different, the teeth of the great white look more similar to those of C. / O. subauriculatus (chubutensis) than to those of this shortfin mako (Isurus oxyrinchus), and the teeth of the latter look more similar to those of a number of megatooths shown here, even though both the great white and mako are mackerel sharks (order Lamniformes), and the others are megatooths which are supposed to be in the same genus as Megalodon, and consensuses change over time, like about how ape-like or human-like Lucy the australopithecine was. That is oversimplification, is like to say that a puma is related to the tiger jus for been "cats". Sharks are not that simple, and the while superficially the tooth of the megalodon looks like the one of the white shark, they had important differences in the form and function, in fact it seems that the white shark ancestors player a role in the extinction of the megalodon. Definitelly they do not belong to the same species and when you see something that "likes like", you most take in count the convergent evolution too. Under your understanding, Cretaxirina is also related with the white shark just because they had afinities, but it is not. There were several species of mega-toother sharks and the white shark is not one of them. (09-15-2020, 09:11 PM)GuateGojira Wrote:(09-15-2020, 08:51 PM)BorneanTiger Wrote: Though they are different, the teeth of the great white look more similar to those of C. / O. subauriculatus (chubutensis) than to those of these mako sharks (genus Isurus), and the teeth of the latter look more similar to those of a number of megatooths shown here, even though both the great white and mako are mackerel sharks (order Lamniformes) which are outside the genus Otodus, and the others are megatooths which are supposed to be in the same genus as Megalodon, that is Otodus (or formerly Carcharocles), and consensuses change over time, like about how ape-like or human-like Lucy the australopithecine was. Of course, aside from the issue of convergent evolution giving different species similar physical characteristics.
The world of the Carcharocles (Otodus) megalodon:
In order to investigate an animal is good to know what other creatures lived with it. Normally the "fans" of this shark promote the idea that it was a whale killer and put images of oversized great white sharks killing sperm whales, but that is incorrect. In fact, in the time of this species, there were not sperm whales, at least not the ones that we know, check this image of the "sperm whales"of that period:  *This image is copyright of its original author This is a comparative image made by "Palaeos", the Paleontologist from Mexico that has his own youtube channel and is one of the best experts that I know. As we can see, appart from Livyatan melvillei, all the sperm whales were small. By the way, that image of Livyatan is from the smallest estimation (13.5 m), the biggest estimation will be this (check the comparison with the biggest length recorded for the sperm whale):  *This image is copyright of its original author Other thing is the size of the prey of "megalodon", and as the prey where whales, the "fans" spread the idea that the whales in that time were like the modern ones and put images of sharks killing blue whales! However the truth is that the biggest whales in those days barely reached the 10 meters long, check this comparative images with the whales of that period made by artist "artbyjrc":  *This image is copyright of its original author So, the biggest prey was smaller than the predator, if the biggest "megalodon" was of about 16 meters and the biggest whale was of 10 meters, the average "megalodon" was of about 10 meters and the average whale of the largest species was of about 6 meters, clearly the shark had advantage on this, so no "fair fight" in this case. Finally, what about the orca? Remember that I told you that in those days there where no big orcas of 8-9 meters long, but only an species named Orcinus citoniensis that measured about 4 meters long (skull of about 60 cm), this is the reconstruction and its skull:  *This image is copyright of its original author  *This image is copyright of its original author By the way, the predator dolphins of those days were also small, check this image:  *This image is copyright of its original author Based on this, most of the animals that lived in the time of "megalodon" were much smaller than it, with the maximum lengths recorded at 10 m for the biggest Cetotherium. Only the Livyatan was the only animal that matched the size of the giant shark. Hope this helps to had a better idea of the world of the "megaldon" and its neighbors. I leave you the video of "Paleos" about the Livyatan and Megalodon for future references: 
Credit to extintanimalsfacts
 *This image is copyright of its original author
|
| Users browsing this thread: |
| 5 Guest(s) |