Top 4 most annoyingly-popular dino hypotheses.

Last edited by JD-man on Sun Oct 22, 2023 5:19 am; edited 1 time in total

I originally posted the following at deviantART ( http://jd-man.deviantart.com/journal/SD-Top-4-most-annoyingly-popular-dino-hypotheses-395469447 ). Now, I'd like to know what you guys think are the most annoyingly-popular dino hypotheses in recent years & why.

Quote :: Hi everybody,

This journal entry was inspired by the Nostalgia Critic's "Top 10 Films I Hate But Everyone Else Loves" ( https://www.youtube.com/watch?v=-ejMFvssoSI ). It's nothing formal, just a list of what I (as a non-expert dino fan) think are the most annoyingly-popular (I.e. More popular than they should be given the evidence) dino hypotheses in recent years (I.e. Post-2000) & why. Even still, I hope that at least some of you will get something out of it. As for why "Top 4", to quote Santa Claus ( https://www.youtube.com/watch?v=Y_KMYPsPNXQ ), "I've� checked it more than once, but� less than 10 times, because around 4 I get bored."

Cheers,
Herman Diaz

4) Troodon, Oviraptor, & Citipati in particular & non-bird maniraptorans in general had paternal care, "possibly within a polygamous mating system" ( http://www.esf.edu/EFB/faculty/documents/varricchio2008paternalcaredinosours.pdf ). I have 2 major problems w/this hypothesis: 1) Varricchio et al. use maximum rather than average values for clutch size (which doesn't make sense to me given that "Troodon clutches vary from 12 to 24 eggs": http://studentresearch.wcp.muohio.edu/vertebrateevolution/dinoasurreprodparenting00.pdf ); 2) Varricchio et al. focus "on the absence of medullary bone to weigh the data, for which a single troodontid specimen and a single specimen of *Citipati osmolskae* are exemplars of" (which doesn't make sense to me given that "multiple brooding oviraptorids are known": [url="http://web.archive.org/web/20111120174744/http://dml.cmnh.org/2011Jan/msg00260.html"]http://web.archive.org/web/20111120174744/http://dml.cmnh.org/2011Jan/msg00260.html[/url] ).

3) Dracorex & Stygimoloch were juvenile & sub-adult stages, respectively, of Pachycephalosaurus ( http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0007626 ). I have 2 major problems w/this hypothesis: 1) It's based on a CAST of the Dracorex skull, & thus it ignores the adult features of the original skull (See "DISCUSSION": [url="https://web.archive.org/web/20100613092039/http://www.childrensmuseum.org/themuseum/dinosphere/draco_rex/dracorex_hogwartsia.pdf"]https://web.archive.org/web/20100613092039/http://www.childrensmuseum.org/themuseum/dinosphere/draco_rex/dracorex_hogwartsia.pdf[/url] ); 2) It ignores the non-ontogenetic differences btwn Dracorex & Stygimoloch (Again, see "DISCUSSION").

2) Deinonychus in particular & non-bird theropods in general were like Komodo dragons in that they hunted alone or in non-cooperative mobs & not cooperative packs ( http://pds17.egloos.com/pds/201004/29/62/Theropod_Dinosaur.pdf ). I have 2 major problems w/this hypothesis: 1) Some of its arguments are very misleading (if not just plain wrong);* 2) It ignores MOR 682 (See the Maxwell quote) despite having cited Maxwell & Ostrom 1995 ( [url="https://sci-hub.tw/https://www.jstor.org/stable/4523664?seq=1"]https://sci-hub.tw/https://www.jstor.org/stable/4523664?seq=1[/url] ).

1) Sauropods lacked an avian-style gastric mill & compensated for this "by greatly increasing food retention time in the digestive system" ( http://rspb.royalsocietypublishing.org/content/274/1610/635.full.pdf ). I have 2 major problems w/this hypothesis: 1) It's based on the comparison of sauropod gastroliths to ostrich gastroliths while ignoring moa gastroliths; Like sauropods, moas were herbivorous browsers (See the Shugart quote) while ostriches are omnivorous grazers ( http://wildwelfare.org/wp-content/uploads/2017/09/Common-Ostrich.pdf ); It's probably no coincidence, then, that like sauropod gastroliths, moa gastroliths are polished (Again, see the Shugart quote) while ostrich gastroliths are pitted; 2) It fails to explain sauropod digestion for the same reason that gigantothermy fails to explain non-bird dino physiology; To quote Holtz, it "might apply to large dinosaurs, but would not apply to small species or to babies" (See "Gigantothermy" under "Complications": http://www.geol.umd.edu/~tholtz/G104/lectures/104endo.html ).

Dishonorable Mention) The Lark Quarry Dinosaur Tracksite records neither a large theropod ( http://www.uq.edu.au/dinosaurs/documents/Romilio_Salisbury_2010.pdf ) nor a dinosaur stampede ( http://www.uq.edu.au/dinosaurs/documents/Romilio_et_al_2013.pdf ). Poropat's & Thulborn's DML posts ( http://comments.gmane.org/gmane.science.dinosaurs.general/56325 ) sum up my problems w/this hypothesis. However, this hypothesis didn't make the "Top 4" for 2 main reasons: 1) It's more recent than all of the aforementioned hypotheses; 2) It's already been dissected in the literature ( http://www.tandfonline.com/doi/abs/10.1080/03115518.2013.748482?journalCode=talc20 ).

*E.g. It's implied that lone adult Komodo dragons can kill prey 10x their size w/"only ser- rated teeth", the logic being that lone adult Deinonychus would've done the same. However, it's been known since 2005 that the former are venomous ( http://www.academia.edu/462746/Early_evolution_of_the_venom_system_in_lizards_and_snakes ), hence why they can kill prey 10x their size. It's also implied, based on Horner & Dobb 1997, that the multiple Deinonychus individuals represented at YPM 64-75 were immature, the logic being that "larger (older) animals are more voracious cannibals than smaller (younger) animals, and smaller conspecifics are more often eaten than larger". However, Horner & Dobb 1997 is neither a peer-reviewed source nor points to a peer-reviewed source, & thus "the information is not likely to be useful" ( http://anthropology.ua.edu/bindon/ant570/pap_rule.htm ). AFAIK, the only relevant peer-reviewed source is Ostrom 1969 (according to which there is no "evidence of immature individuals at this site": http://peabody.yale.edu/sites/default/files/documents/scientific-publications/ypmB30_1969.pdf ).

Quoting Maxwell ( http://www.naturalhistorymag.com/htmlsite/master.html?http://www.naturalhistorymag.com/htmlsite/1299/1299_feature.html ): "Laid out in its death pose at this new site was a beautifully preserved, near-complete specimen of a young Tenontosaurus. Four Deinonychus teeth were found alongside the bones; later, in the laboratory, seven more teeth were uncovered. It's possible that a few more teeth were missed in the field or unwittingly discarded during preparation because they were concealed within small lumps of rock. So we have a subadult Tenontosaurus no more than fourteen feet long (compared with a length of about twenty feet for the adult at the Shrine site), preserved with at least eleven Deinonychus teeth.

But how can we distinguish between the remains of a victim hunted down and devoured by a pack and an animal that simply died and was scavenged by a few passing Deinonychus? As is the case at the Shrine site, this Tenontosaurus was preserved where it died. After death, the desiccation of the abundant supporting tendons that line the vertebrae of the neck and tail cause these parts to coil. The tail of Tenontosaurus, which accounts for about one-third of the animal's total length, is particularly heavy with supporting tendons. In this specimen, the pronounced curvature of the tail and the neck toward each other effectively counters any claim that the bones were carried to the site by water currents. The Deinonychus teeth were found in the region of the abdomen and pelvis, suggesting that the predators lost their teeth while feeding on the viscera. Most modern carnivores begin with the areas around the anus and abdomen when they feast on freshly killed prey, and it's likely that carnivorous dinosaurs did the same.

The number of teeth indicate that more than one Deinonychus was involved with the carcass. Like all other theropod dinosaurs, Deinonychus shed and replaced teeth throughout its life. The teeth would fall out upon the animal's reaching maturity but also could be wrenched out earlier by the stress associated with the biting and tearing of flesh. Because of this, theropod teeth are very common in sediments containing dinosaur fossils. The teeth from this site vary from recently erupted to fully mature ones. Given that Deinonychus had only sixty teeth in its jaws at any one time, it's unlikely that all eleven were wrenched from the mouth of just one feeding animal. This would leave the Deinonychus toothless after five similar meals. The possibility that Deinonychus was replacing shed teeth in a few weeks or months, and therefore had the ability to sustain such dramatic tooth loss, was quashed by Greg Erickson, who, as a master's degree student at the Museum of the Rockies, worked on replacement rates of teeth in various dinosaurs and living reptiles. After CT-scanning portions of the lower jaw of Deinonychus and studying individual teeth, he came up with an estimate of 300 days for the time it took Deinonychus to replace a shed tooth with a mature one.

We know that this Tenontosaurus was not yet an adult, so it didn't die of old age. Of course, this doesn't rule out death from disease or injury and doesn't confirm that it was cut down by a pack, but it's a start. Next, we have a concentration of teeth around the abdomen and pelvis. This may indicate that the pack fed on the abdominal contents while they were still warm and moist. If, after the viscera had been consumed, the remainder of the carcass was scavenged over time by many individuals, we would expect a much more disturbed carcass and a wider scattering of teeth. Similarly, if the Tenontosaurus had been killed by a larger predator-such as the unknown owner of the three-inch-long serrated teeth that occasionally crop up in the Cloverly formation—then whatever remained of the carcass would have been strewn around the area."

Quoting Shugart ( http://www.amazon.com/Earthquake-Other-Tales-Unbalanced-Nature/dp/0300122705 ): "When the Polynesians arrived in New Zealand, they encountered birds that had been evolving for 80 million years without the presence of mammalian predators. Among the most striking of these animals must have been the moas (Figure 29). These were gigantic wingless birds standing as much as 10 feet (3 m) tall and weighing as much as 550 pounds (250 kg).1 They are known from a diverse array of remains including eggshells, eggs, a few mummified carcasses, vast numbers of bones, and some older fossilized bone. The eleven moa species that are currently recognized occupied ecological niches customarily filled elsewhere by large mammalian browsing herbivores. They may have had relatively low reproductive rates; apparently, they usually laid only one egg at a time.2
Moas ranked in height from the tallest at about 10 feet to smaller species the size of a large domestic turkey (about 3 feet, or 1 m, tall and weighing 45 pounds, or 20 kg). They were unique in having neither wings nor even residual wing bones. As one expects of large birds that feed on vegetable matter, moas had muscular gizzards. They swallowed small stones up to 2 inches (50 mm) in diameter into their gizzards for grinding food before digestion. These polished stones, called gastroliths, often occur in groups along with moa bones.3
Many gastroliths have been found in what are now human-modified grassy habitats, giving the initial impression that moas were grass-eating animals. But the present vegetation at a site may not be its previous vegetation.4 Based on preserved crop contents from mummified specimens, moas fed on leaves, seeds, and green twigs of trees and parts of shrubs.5 Thus, it appears that they were creatures of the forest and shrub- land—more like browsing deer than grazing cows."

I originally posted the following at deviantART ( https://www.deviantart.com/jd-man/journal/SD-Most-annoyingly-popular-dino-hypotheses-addend-842963661 ).

Quote :: This journal entry is an addendum to "SD: Top 4 most annoyingly-popular dino hypotheses" ( https://www.deviantart.com/jd-man/journal/SD-Top-4-most-annoyingly-popular-dino-hypotheses-395469447 ). I hope that at least some of you will get something out of it.

#3 Update) I've since come around to this hypothesis, partly b/c I was told to think about it in the context of Nanotyrannus (which helps to explain the seemingly adult features of Dracorex: https://www.smithsonianmag.com/science-nature/the-origin-of-a-little-tyrant-130792981/ ), & partly b/c I was told to think about it in the context of Triceratops (which, like Pachycephalosaurus, became less spiky w/age: http://whenpigsfly-returns.blogspot.com/2010/07/toroceratops.html ).

#1 Update) I've since come around to this hypothesis, partly b/c I was told to think about it in the context of green iguanas (See 13:00-14:30, which helps to explain baby sauropod digestion: https://archive.org/details/WildlifeDocumentaries/Wildlife+On+One+-+S31+-+E04+-+Iguanas%2C+Living+Like+Dinosaurs.avi ), & partly b/c I was told to think about it in the context of geese (See 12:00-13:30, which also helps to explain baby sauropod digestion: https://www.youtube.com/watch?v=2bj0wBMkr5M ).

New #3 Contender) Tie btwn 1) Spinosaurus being quadrupedal ( https://sci-hub.ru/https://www.science.org/doi/10.1126/science.1258750 ), & 2) theropods not having lips (See "Fig. 3": https://sci-hub.ru/https://www.science.org/doi/10.1126/science.1062681 ):
-1) Now that "Ibrahim et al. 2020b" has been published, this hypothesis isn't as annoyingly-popular (See "Posture and balance": https://markwitton-com.blogspot.com/2020/05/spinosaurus-2020-thoughts-for-artists.html ). However, btwn 2014-2020, it was everywhere, even in otherwise great books.* My major problem is that it's "an extraordinary claim, but [the paper] fails to provide extraordinary evidence for the proportions and center of gravity that make or break this claim" ( https://www.skeletaldrawing.com/home/there-may-be-more-fishiness-in-spinosaurus9132014 ).
-2) Despite the fact that we've known better since at least the "Dinosaur Renaissance" (See pages 142-145: http://doc.rero.ch/record/232376/files/PAL_E1363.pdf ) & have gone through the "All Yesterdays" movement (a large part of which was un-shrink-wrapping: https://svpow.com/2010/12/13/pimp-my-pod-2-haids/ ), this hypothesis keeps coming back. My major problem is that it seems to rely on hand-waving/ignoring the fact that theropod oral anatomy is MUCH more like that of lipped tetrapods than lipless ones. Said anatomy it best described by Hartman ( https://www.skeletaldrawing.com/home/the-lip-post1 ) & best illustrated by GSPaul (See "Archosaur Lip Anatomy", page 26: http://assets.press.princeton.edu/chapters/i10851.pdf ).

*I'm specifically referring to Chuang/Yang's "THEM: Age Of Dinosaurs" ( https://blog.everythingdinosaur.co.uk/blog/_archives/2018/09/07/chinese-dinosaur-art-spinosaurus.html ) & Norell's "The World of Dinosaurs: An Illustrated Tour" ("Theropods were for the most part bipedal, yet a few, such as Spinosaurus, may have been secondarily quadrupedal").

New #1 Contender) "Juvenile and adult[...Deinonychus...]likely consumed different prey" & thus didn't live in packs ( https://sci-hub.ru/https://www.sciencedirect.com/science/article/abs/pii/S003101822030225X ). I have 2 major problems w/this hypothesis: 1) Its results don't really support its conclusions;* 2) It ignores A LOT of contradictory evidence.**

*Quoting Willoughby ( https://web.archive.org/web/20240128091809if_/https://scontent-sea1-1.xx.fbcdn.net/v/t1.15752-9/422590719_288119194270713_8067562584829932676_n.png?_nc_cat=105&ccb=1-7&_nc_sid=8cd0a2&_nc_ohc=lbcQo7A8iKMAX8wf10U&_nc_ht=scontent-sea1-1.xx&oh=03_AdT3TdxIrp3Ubm9f3ONtT2GGw8G9ypHWLBtinZP9OFCU6Q&oe=65DD7559 ): "A handful of teeth were taken from two sites, divided into a large (adult) and small (juvenile) group of 5 to 6 teeth each, and then a t-test computed for significant mean differences. Only one of the two sites showed a mean diff across size/age groups at p < .05, the other did not."

**In reference to consuming different prey:
-It ignores the "higher proportion of smaller prey items and smaller proportion of larger prey" in the diet of accipitrids "during nesting" (Golden eagles: https://static02.nmbu.no/mina/studier/moppgaver/2012-Skouen.pdf ) (Sparrowhawks: https://www.tandfonline.com/doi/pdf/10.1080/00063657.2014.940838 ). Since eudromaeosaurs were basically "terrestrial hawks" in terms of ecology/behavior ( https://qilong.wordpress.com/2011/12/19/dromaeosaurs-are-terrestrial-hawks/ ), it makes sense that the same would've gone for them. This reminds me of how much I miss "ASK A VELOCIRAPTOR" (which summed up what we knew or could infer about real Velociraptor in a silly/fun way): https://askvelociraptor.tumblr.com/post/23590224406/while-currently-lacking-any-females-andor
-It uses Varricchio et al. 2008 to argue that Deinonychus had Rhea-like paternal care despite the facts that 1) that paper doesn't cover any dromaeosaurids, let alone eudromaeosaurs, & 2) unlike the "more stork-like" omnivores that paper does cover, eudromaeosaurs were raptorial hypercarnivores (See the 1st Bakker quote AWA page 6 in this link: https://books.google.com/books?id=hTTUBAAAQBAJ&pg=PA6&dq=%22stork-like+than+raptorial%22&hl=en&sa=X&ved=0ahUKEwiz4LzOtbDWAhUGOiYKHSyHD5MQ6AEIKDAA#v=onepage&q=%22stork-like%20than%20raptorial%22&f=false ).
-It focuses on teeth, yet ignores the fact that "juvenile teeth display the same features as those of adults, but on a smaller scale" ( https://www.academia.edu/1974330/SWEETMAN_S._C._2004._The_first_record_of_velociraptorine_dinosaurs_Saurischia_Theropoda_from_the_Wealden_Early_Cretaceous_Barremian_of_southern_England._Cretaceous_Research_25_353-364 ), which means "that hatchlings were feeding on prey tissue of the same general texture and consistency as that fed upon by adults" (See the 2nd Bakker quote).

Quoting Bakker (See "Raptor Red"): "Female dominance is a powerful piece of evidence that permits us to reconstruct the private lives of Cretaceous predatory dinosaurs. A family structure built around a large female is rare in meat-eating reptiles and mammals today, but it's the rule for one category of predatory species — carnivorous birds. Owls, hawks, and eagles have societies organized around female dominance, and we can think of tyrannosaurs and raptors as giant, ground-running eagles."

Quoting Bakker (See Wolberg's "Dinofest International: Proceedings of a Symposium Sponsored By Arizona State University", page 62): "A striking difference exists in modern communities between cold-blooded predators and hot-blooded predators. Most bird and mammal species feed their young until the youngsters are almost full size; then and only then do the young set out to hunt on their own. Consequently, the very young mammals and birds do not chose food items independently of the parents. Young lions and eagles feed on parts of carcasses from relatively large prey killed by the parents. Most snakes, lizards, and turtles do not feed the young after birth, and the new-born reptiles must find prey suitably diminutive to fit the size of the baby reptilian jaws and teeth. A single individual lizard during its lifetime usually feeds over a much wider size range of prey than a single individual weasel or hawk, because the lizard begins its life hunting independently.
Therefore, a predatory guild of three lizard species with adult weights 10g, 100g and 1000g would require a much wider range of prey size than a guild of three mammal predator species with the same adult weights. If allosaurs had a lizard-like parental behavior, then each individual allosaur would require a wide size range in prey as it grew up. The evidence of the Como lair sites strongly suggests that the dinosaur predatory guild was constructed more like that of hot-blooded carnivores than that of lizards or snakes.
This theory receives support from the shape of the baby allosaur teeth. In many cold-blooded reptilian predators today, the crown shape in the very young is quite different from the adult crown shape. For example, hatchling alligators have the same number of tooth sockets in each jaw as do the adults, but the hatchling crowns are very much sharper and more delicate. In the hatchling all the teeth are nearly the same shape, and the young gators have less differentiation of crown size and shape along the tooth row; the hatchlings lack the massive, projecting canine teeth and the very broad, acorn-shaped posterior crowns of the adults. Young gators feed extensively on water insects, and the sharp crowns are designed for such insectivorous habits. Adult gator species use their canine teeth for killing large prey, such as deer, and employ the acorn crowns to crush large water snails and turtles (Chabreck, 1971; Delaney and Abercrombie, 1986; McNease and Joanen, 1977; Web et al, 1987).
If allosaur hatchlings fed independent of adults, I would not expect the hatchling tooth crowns to be the same over-all shape as that of the adult. However, the over-all tooth crown shape in the tiniest allosaur IS identical to that of the adult (figs. 3,4). Thus it appears that hatchlings were feeding on prey tissue of the same general texture and consistency as that fed upon by adults."

**In reference to not living in packs: It ignores the best evidence for pack-hunting in Deinonychus (I.e. Shed teeth in general & MOR 682 in particular; See the Maxwell quote) despite having cited Maxwell & Ostrom 1995 ( https://sci-hub.st/https://www.jstor.org/stable/4523664 ). In other words, Deinonychus pack-hunting probably looked something like this: https://softdinosaurs.files.wordpress.com/2012/07/antlers-formationwtmk.jpg

Quoting Maxwell ( https://www.naturalhistorymag.com/htmlsite/master.html?https://www.naturalhistorymag.com/htmlsite/1299/1299_feature.html ): "Nobody knows for certain what took place at the Shrine site. We do know, however, that whether hunted down and killed by a pack or simply scavenged after death, Tenontosaurus was the preferred food of Deinonychus. Approximately eighty occurrences of Tenontosaurus remains have been discovered in the Cloverly formation to date, and thirty-five include Deinonychus teeth. While Deinonychus fossils are rarely found with other possible prey animals, three or four Deinonychus teeth typically turn up wherever there are Tenontosaurus remains. And at a site discovered in the Cloverly formation in 1992, there were even more.

Laid out in its death pose at this new site was a beautifully preserved, near-complete specimen of a young Tenontosaurus. Four Deinonychus teeth were found alongside the bones; later, in the laboratory, seven more teeth were uncovered. It's possible that a few more teeth were missed in the field or unwittingly discarded during preparation because they were concealed within small lumps of rock. So we have a subadult Tenontosaurus no more than fourteen feet long (compared with a length of about twenty feet for the adult at the Shrine site), preserved with at least eleven Deinonychus teeth.

But how can we distinguish between the remains of a victim hunted down and devoured by a pack and an animal that simply died and was scavenged by a few passing Deinonychus? As is the case at the Shrine site, this Tenontosaurus was preserved where it died. After death, the desiccation of the abundant supporting tendons that line the vertebrae of the neck and tail cause these parts to coil. The tail of Tenontosaurus, which accounts for about one-third of the animal's total length, is particularly heavy with supporting tendons. In this specimen, the pronounced curvature of the tail and the neck toward each other effectively counters any claim that the bones were carried to the site by water currents. The Deinonychus teeth were found in the region of the abdomen and pelvis, suggesting that the predators lost their teeth while feeding on the viscera. Most modern carnivores begin with the areas around the anus and abdomen when they feast on freshly killed prey, and it's likely that carnivorous dinosaurs did the same.

The number of teeth indicate that more than one Deinonychus was involved with the carcass. Like all other theropod dinosaurs, Deinonychus shed and replaced teeth throughout its life. The teeth would fall out upon the animal's reaching maturity but also could be wrenched out earlier by the stress associated with the biting and tearing of flesh. Because of this, theropod teeth are very common in sediments containing dinosaur fossils. The teeth from this site vary from recently erupted to fully mature ones. Given that Deinonychus had only sixty teeth in its jaws at any one time, it's unlikely that all eleven were wrenched from the mouth of just one feeding animal. This would leave the Deinonychus toothless after five similar meals. The possibility that Deinonychus was replacing shed teeth in a few weeks or months, and therefore had the ability to sustain such dramatic tooth loss, was quashed by Greg Erickson, who, as a master's degree student at the Museum of the Rockies, worked on replacement rates of teeth in various dinosaurs and living reptiles. After CT-scanning portions of the lower jaw of Deinonychus and studying individual teeth, he came up with an estimate of 300 days for the time it took Deinonychus to replace a shed tooth with a mature one.

We know that this Tenontosaurus was not yet an adult, so it didn't die of old age. Of course, this doesn't rule out death from disease or injury and doesn't confirm that it was cut down by a pack, but it's a start. Next, we have a concentration of teeth around the abdomen and pelvis. This may indicate that the pack fed on the abdominal contents while they were still warm and moist. If, after the viscera had been consumed, the remainder of the carcass was scavenged over time by many individuals, we would expect a much more disturbed carcass and a wider scattering of teeth. Similarly, if the Tenontosaurus had been killed by a larger predator-such as the unknown owner of the three-inch-long serrated teeth that occasionally crop up in the Cloverly formation—then whatever remained of the carcass would have been strewn around the area."

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