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Deinosuchus

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This peer review discussion has been closed.
I've listed this article for peer review because I'd like to get it cleaned up as much as possible prior to a featured article nomination. I believe the article is currently comprehensive and well-sourced, but I'm sure there are at least a few minor things that should be fixed first, and a few more pairs of eyes might help in catching this.

Thanks, FanCollector (talk) 04:44, 13 January 2009 (UTC)[reply]


Although I specialize more in Deinosuchus chow, I'll give this a going-over in the next few days. From a quick scan it looks very solid; it's great to get more editors who know their way around the literature! J. Spencer (talk) 04:54, 14 January 2009 (UTC)[reply]

Okay, here I go. I'll do the lead last, after I've read through the rest of the article.

Description:

  • Heading: Morphology and physiology = I removed "physiology", as that section only deals with physiology in passing (the effect of the osteoderms' bracing).
  • It may be useful to state somewhere near the beginning what material is known for this genus, not in terms of specimen numbers, but something general to the effect of "The skeleton of Deinosuchus is partially known, with the skull, vertebrae, and osteoderms well-represented."
  • I would reorder a few sections, to put all of the cranial description together, and so forth. Here's a quick stab at it (4th and 2nd paragraph switched places):

Despite its massive size, the overall physical appearance of Deinosuchus was not considerably different from that of modern crocodilians.[1] Deinosuchus had an alligator-like broad snout, with a slightly bulbous tip.[1] Each premaxilla contained four teeth, with the pair nearest to the tip of the snout being significantly smaller than the other two.[2] Each maxilla (the main tooth-bearing bone in the upper jaw) contained 21 or 22 teeth.[3] The tooth count for each dentary (tooth-bearing bone in the lower jaw) was approximately 22.[2] All of the teeth were very thick and robust; those close to the rear of the jaws were short, rounded, and blunt.[4] They appear to have been adapted for crushing, rather than piercing.[4] When the mouth was closed, only the fourth tooth of the lower jaw would have been visible.[2]

The bite force of Deinosuchus has been estimated to exceed 18,000 newtons.[1] In contrast, modern American alligators, with the strongest bite of any living animal, top out at 9,452 newtons.[5] Even the largest and strongest theropod dinosaurs, such as Tyrannosaurus, probably had a bite force inferior to that of Deinosuchus.[5]

Deinosuchus had a secondary bony palate, which would have permitted it to breathe through its nostrils while the rest of the head remained submerged underwater.[6] The vertebrae were articulated in a procoelous manner, meaning that they had a concave hollow on the front end and a convex bulge on the rear; these would have fit together to produce a ball and socket joint.[7][8] The secondary palate and procoelous vertebrae are advanced features also found in modern eusuchian crocodilians.[6][9]

The osteoderms (scutes) covering the back of Deinosuchus were unusually large, heavy, and deeply pitted; some were of a roughly semispherical shape.[10][11] Deep pits and grooves on these osteoderms served as attachment points for connective tissues.[11] Together, the osteoderms and connective tissues would have served as load-bearing reinforcement to support the massive body of Deinosuchus out of water.[11][3] Consequently, despite its bulk, Deinosuchus was probably almost as agile on land as its modern relatives.[3][6]

  • Size: what kind of tons are in use in the Schwimmer reference?
  • Although the book doesn't explicitly say so, context on p.50 makes it clear that metric tons are being referenced. ("the typical Deinosuchus of the eastern Gulf Coast would weigh in at about 2300 kg, or 2.3 tons...") I've changed the weight references to say "tonnes" with the appropriate wikilink. FanCollector (talk) 11:19, 15 January 2009 (UTC)[reply]
  • I'd consider combining the last two short paragraphs in the Size section.

Will be back shortly for the next section. J. Spencer (talk) 02:52, 15 January 2009 (UTC)[reply]

Paleobiology:

  • Habitat: If the information is available, and it may not be practical given the wide distribution, it may be useful to include a brief description of the contemporaneous fauna, i.e. "Deinosuchus shared its shallow-water coastal habitat with a variety of ammonites, sharks, mosasaurs, turtles,..." Does Schwimmer have a general description like this in his book?
  • As you note, the problem is that there are such a wide variety of habitats. Incomplete information is also a problem: according to Schwimmer (2002, p.35) "the environmental setting inhabited by the Montana D. hatcheri is not known with certainty"; even though it was from the Judith River Formation, it was not made clear exactly which part. Schwimmer does describe a few animals in Deinosuchus habitat in Alabama, as part of a hypothetical scenario which involves the crocodilian ambushing a tyrannosaurid. These animals include two birds (Ichthyornis and Baptornis), fish (Enchodus), and a few other animals. Some articles on the Aguja Formation describe the dinosaurs that lived alongside Deinosuchus in Texas - Kritosaurus and Chasmosaurus are probably the best known, plus a bunch of fragments, teeth, etc. However, these articles don't list other vertebrates such as fish, sea reptiles, etc... About the only place I found a comprehensive list was for the San Juan Basin habitat in New Mexico (Fossil Forest Member). This includes Pentaceratops, a tyrannosaur similar to Daspletosaurus, perhaps two species of hadrosaur, and seven listed species of turtle, plus another primitive alligatoroid (Leidyosuchus). Unfortunately, I can't think of a good way to work in the information I have without overwhelming the section. Perhaps we could add something short and relatively general? Hadrosaurs, ceratopsians, tyrannosaurids, turtles, and other crocodilians are mentioned in multiple habitats. FanCollector (talk) 23:38, 15 January 2009 (UTC)[reply]
  • The third paragraph of this section is quite short. Could it be combined with the first paragraph, or qualified in some way? Maybe the oldest finds are in the X Formation and the youngest are in the Y Formation.
  • I combined the paragraphs. As for a correlation between age and locale, Schwimmer (2002) thought that Deinosuchus evolved in the east and spread from there, since the oldest finds were in the Blufftown Formation near the Georgia-Alabama border. However, this was invalidated by the later Mexico discovery, which came from about the same age (~80 mya). FanCollector (talk) 23:38, 15 January 2009 (UTC)[reply]
  • Rest of Paleobiology: I'd establish the name of a paleontologist once, and then just use the last name. This is mostly in regards to David R. Schwimmer.
  • Otherwise, I shifted a few things around, for purposes of flow and connections between material. Feel free to reverse any of those changes you don't like.

Will review the "Discovery and classification" and the lead tomorrow. J. Spencer (talk) 03:57, 15 January 2009 (UTC)[reply]


Back on:

  • Discovery and classification: I replaced "referred" with "assigned," as I've seen editors at FAC question the use of the word "referred" in the paleo taxonomy sense.
  • "determined that the genus name Phobosuchus was taxonomically invalid" - in what way, out of curiosity?
  • Basically, Phobosuchus turned out to be a polyphyletic genus. When Nopsca coined the name, he included within it several different giant crocodilians, which later turned out not to be closely related. I have updated this portion in the article to make this clearer. FanCollector (talk) 22:04, 17 January 2009 (UTC)[reply]
  • I merged the short paragraph about the legacy of the incorrect skull restoration with the preceding paragraph
  • Looking at the taxobox, D. rugosus and ?D. riograndensis are listed as potentially valid species. This seems a bit odd, as the east-west division has been set up, yet Montanan D. hatcheri predates Texan Phobosuchus riograndensis by decades. If there is an east-west division, shouldn't D. hatcheri be the correct name for the western species? Or is riograndensis doing its own thing?
  • Very good question. Though Brochu (2003, review of Schwimmer 2002) thinks it possible there might be 2 species, he doesn't explicitly say what those species are. A SVP abstract (2000, p.26A) by Anglen and Lehman refers to "all of the known specimens of D. riograndensis". Westgate et al. (2006) also tentatively referred the Mexican Deinosuchus specimen to D. riograndensis, which is the most recent example of this I've found in the literature. In contrast, I haven't found any post-2002 mentions of D. hatcheri except for the 2006 paper by Lucas et al. which says all 3 species are the same. Schwimmer (2002, p.109) seems to assume for whatever reason that D. riograndensis would be the correct name for the western populations if they deserved their own species. ("The relationship between Deinosuchus rugosus in the eastern United States and D. riograndensis in the west becomes the crux of our species analysis.") FanCollector (talk) 22:04, 17 January 2009 (UTC)[reply]
  • Lead: I like the lead quite a bit. The first sentence of the third paragraph does not quite work for me, mostly because of the geographic distinction "eastern," because shortly thereafter the Western Interior Seaway appears. "Eastern" is necessary for apex predator, so that can't go. I might rephrase it something like:

"Deinosuchus fossils have been found in ten U.S. states, as well as northern Mexico. It lived on both sides of the Western Interior Seaway, and was an opportunistic apex predator in the coastal regions of eastern North America. Deinosuchus reached its largest size in its western habitat, but the eastern populations were far more abundant. Opinion remains divided as to whether these two populations represent separate species. Deinosuchus was probably capable of killing and eating large dinosaurs. It may have also fed upon sea turtles, fish, and other aquatic and terrestrial prey."

Anyway, I will sleep on this article and run through it again, to see if I missed something. I found it to be of high quality, and would have had no trouble passing it through GA as-is. I haven't been through an FAC as a primary editor in over a year, so I don't know how/if it is now different, but I think that this article compares favorably with dinosaur FAs of similar length (Lambeosaurus, Psittacosaurus, Styracosaurus), especially considering that Deinosuchus is not known from fossils with the same degree of completeness. J. Spencer (talk) 05:37, 16 January 2009 (UTC)[reply]

Here's a couple more thought on the taxonomy:

  • Insert almost exactly what you wrote above about Polydectes, perhaps at the end of the Emmons paragraph. This came up with the Acrocanthosaurus review: we had "Acracanthus" in the taxobox but not in the body, and someone caught it and wanted more information.
  • At the end of the last paragraph, just put in a sentence or two on those recent usages of D. riograndensis, something like (but perhaps more graceful than): "D. riograndensis, used informally by Schwimmer to described the western population,<Schwimmer ref> is still used by some researchers, including Anglen and Lehman<Anglen and Lehman ref> and Westgate et al.<Westgate ref>."

This will explain why it's included in the taxobox. J. Spencer (talk) 01:34, 18 January 2009 (UTC)[reply]

After another look:

  • "The tooth count for each dentary (tooth-bearing bone in the lower jaw) was approximately 22" - perhaps average tooth count, or maximum tooth count? Approximately seems odd with discrete objects.
  • This was a problematic situation. Although the premaxillary and maxillary tooth counts are explicitly discussed in the text, the dentary tooth count is only shown on a diagram of the jaws (pg.113). I tried to see if it was in some other source, but wasn't able to find any. The diagram, drawn by Schwimmer, clearly shows 22 dentary alveoli (#3 and #4 are conjoined, which is discussed specifically in the text.) The premaxillary and maxillary counts on the diagram match what is written elsewhere in the book. I can remove the word "approximate" if needed, or, if this diagram is not an acceptable source, remove the dentary tooth count entirely. Schwimmer says elsewhere in the text that the dentaries are completely known, so it's unlikely that the pg.113 diagram represents guesswork. FanCollector (talk) 00:06, 20 January 2009 (UTC)[reply]
  • Is there a modern estimate for the length of an adult skull? Also, a cool but superfluous detail might be some dimension for the largest teeth (crown length, total length, something like that).
  • Schwimmer discusses skull size in chapter 3 ("The Size of Deinosuchus"). The skulls from eastern specimens are about 1 m (3.3 ft) long. A newly-discovered Big Bend Deinosuchus specimen was 1.31 m (4.3 ft) long. These are from animals estimated by Schwimmer as 8m and 9.8m in length, respectively. Schwimmer did not give a skull size estimate for the Colbert/Bird specimen because it was too incomplete. His biggest body size estimates (12m) were based on scaling from vertebrae. FanCollector (talk) 00:06, 20 January 2009 (UTC)[reply]
  • That's useful to know. I'd include something about scaling from vertebrae, and at least the size of the eastern skulls (could be added right after the overall length and width in the size section) J. Spencer (talk) 02:57, 20 January 2009 (UTC)[reply]
  • Under Habitat, it might be useful, or it might be too much detail, to include the formations Deinosuchus is known from. It could be as little as the formation(s) in parentheses after the state ("Texas (Aguja Formation),..." Since the article doesn't deal too much with individual formations, stating them may be unnecessary. J. Spencer (talk) 22:54, 19 January 2009 (UTC)[reply]
  • If they don't fit, don't sweat it, as this is one of those "nice to have, but not necessary" details (especially considering that most of the formations wouldn't be mentioned elsewhere in the article). J. Spencer (talk) 02:57, 20 January 2009 (UTC)[reply]

Comments from Casliber

[edit]

OK, looks promising :) ...I'll jot some queries below. Anything striaghtforward I amy just tweak. Casliber (talk · contribs) 02:32, 23 January 2009 (UTC)[reply]

  • "alligatoroid" is an interesting word for the lead. I can see why it is used; do we think it is more informative than "relative of alligator" or even just "alligator"? (are all alligatoroids alligators?)
  • The sources actually don't agree on this. Brochu (1999) calls Deinosuchus "one of the largest alligators, and one of at least two independent instances (the other is Purussaurus) of gigantism within Alligatoroidea." (p.38) This seems to imply that "alligator" is an acceptable term for all members of that clade. In contrast, Schwimmer (2002) says that Deinosuchuus "was an alligatoroid in current terminology, but not an alligator in the strict sense" (p.136) which seems to limit the use of "alligator" to the modern genus. I think that a phrase like "ancient relative of alligators" might work in place of the technical term alligatoroid for the lead; I'll try to think of a non-clumsy way to work it in. FanCollector (talk) 03:18, 23 January 2009 (UTC)[reply]
  • I changed the opening sentence to read as follows:
Deinosuchus (/ˌdaɪnəˈsukəs/) is an extinct relative of alligators that lived 80 to 73 Ma (million years ago), during the Late Cretaceous period.
  • All contents of lead should be expanded later in article. If you rename discovery bit Discovery and naming, tehn you can place Ancient Greek translation there. We have alot of dino Featured Articles to use as templates.
  1. ^ a b c Schwimmer, David R. (2002). King of the Crocodylians: The Paleobiology of Deinosuchus. Indiana University Press. pp. 1–16 (The Life and Times of a Giant Crocodylian). ISBN 0-253-34087-X.
  2. ^ a b c Schwimmer (2002), pp. 107–135 (How Many Deinosuchus Species Existed?)
  3. ^ a b c Schwimmer (2002), pp. 42–63 (The Size of Deinosuchus)
  4. ^ a b Schwimmer (2002), pp. 167–192 (The Prey of Giants)
  5. ^ a b Erickson, Gregory M.; Lappin, A. Kristopher; Vliet, Kent A. (2003). "The ontogeny of bite-force performance in American alligator (Alligator mississippiensis)" (pdf). Journal of Zoology. 260 (3): 317–327.
  6. ^ a b c Cloudsley-Thompson, J.L. (2005). Ecology and Behaviour of Mesozoic Reptiles. Springer. pp. 40–41. ISBN 3-540-22421-1.
  7. ^ Colbert, Edwin H; Bird, Roland T. (1954). "A gigantic crocodile from the Upper Cretaceous beds of Texas". American Museum Novitates. 1688. American Museum of Natural History. {{cite journal}}: External link in |title= (help)
  8. ^ Foster, John (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. p. 150. ISBN 978-0-253-34870-8.
  9. ^ Rolleston, George; Jackson, William Hatchett (1870). Forms of Animal Life. Oxford at the Clarendon Press. p. 392.
  10. ^ Holland, W.J. (1909). "Deinosuchus hatcheri, a new genus and species of crocodile from the Judith River beds of Montana". Annals of the Carnegie Museum. 6: 281–294.
  11. ^ a b c Schwimmer (2002), pp. 17–41 (The Early Paleontology of Deinosuchus)
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