Abstract
-Switch and rephrase the last two sentences
-Provide brief justification for your taxonomic identification
Introduction
-Who says the Kayenta Formation is Sinemurian? Myself and others suggest (and have good evidence to support) that it could also include the Pliensbachian.
-The Kayenta Formation has been studied and explored for a lot longer than 1942. Dutton first mapped those strata in 1882 and Ward revised them in 1901 and 1905. It's true that the 40s saw the first major collection of body fossils in the Dilophosaurus skeletons near Moenave, AZ.
-Gold Tooth Springs isn’t a place. Gold Spring?
-You don’t need to quote “silty facies” because it’s a formal lithostratigraphic name (Harshbarger et al., 1957). You can say the Silty Facies of the Kayenta Formation. You do this here (page-line):1-34, 2-20, 2-31, 2-35, 3-3, 3-11, 3-13, Figure 2.
Materials and Methods
-“Curated there in perpetuity” is redundant after mentioning that the fossils have been accessioned.
-What are “standard field paleontology surface collection techniques”? These vary widely from person to person, even within a single crew.
-Use “Paraloid B-72” to indicate the grade name. For clarification, see Amy Davidson’s email to the Preplist at: https://lists.fas.harvard.edu/mailman/private/preplist/2014-August/003151.html
Geological Setting
-Mention that Washington County is in Utah
-The debate as to whether or not the Springdale Sandstone Member is the base of the Kayenta Formation or the top member of the Moenave Formation is not resolved, and it being part of the Kayenta isn’t even the most recent opinion (Steiner and Tanner, 2014).
-The J-0 unconformity is not the same as the J-sub-K unconformity. As defined, the J-0 unconformity is at the base of the Glen Canyon Group (or Nugget Sandstone), be that the Wingate Sandstone or Moenave Formation depending on your location (Pipiringos and Peterson, 1978; Peterson and Pipiringos, 1979; even though they fail to realize that Gregory’s Division A actually includes the Wingate). The J-sub-K underlies the Kayenta Formation but is above the Wingate. This is where you get back to the Springdale Sandstone problem, because it is supposed to also be above the J-sub-K (Riggs and Blakey, 1993; Lucas and Tanner, 2006). You even mention that the Springdale unconformably overlies the Whitmore Point Member.
-Be very careful about not generalizing the lithology of the Kayenta Formation when describing it near your locality. Even from Kanab to Ward’s Terrace, the Silty Facies changes dramatically, and being a mixed fluvial-eolian system can be expected to be extremely time-transgressive as well as facies-transgressive. It doesn’t necessarily correlated well with places like Gold Spring, where tetrapod trackways or fish aren’t as common. At the time, Utah was much closer to the oceans and was probably wetter than conditions at Gold Spring.
Description
-This paragraph reads awkwardly, reconsider rewriting.
-I’m not left convinced that these fossils are from a single taxon. Didn’t you collect pieces over three years? The fact that the Kayenta here isn’t full of fossils is the strongest evidence for that claim, but you don’t mention over how much area these remains were collected. With their fragmentary nature and difficulty of identifying elements, identifying duplication seems trivial.
Differential Diagnosis
-I will reserve most of my opinion on what these elements are for another forum. But I will say, you need to use apomorphy-based identifications (Nesbitt, Irmis, Parker, 2007). You mention that “no unambiguous autapomorphies are recognized”, but the lack of autapomorphies found in other taxa doesn’t an identification make. It’s completely fine to say cf. Sphenosuchia, but that’s a big difference from calling it Sphenosuchia indet. Even if you have to resort to calling it “Archosauria” or even “Reptilia”, you’re still reporting the first archosaurs or reptile remains for that part of the formation. You’re reporting this as a single individual, but if it’s not, you should ID (based on apomorphies) each bone individually (eg. if that’s a ventral keel on a cervical vertebra [Fig. 7.4], you’re looking at Archosauriformes).
Figures
-What is the red bar beside the Kayenta Formation in the strat column?
-Figure 4.2 and 4.3 are a little dark. I can’t tell if those pits are cranial ornamentations or dissolution pits from weathering.
-Figure 6.1 is very blurry, do you know any directions on the element?
-Figure 13.5-8 are blurry
Thanks for the feedback Adam! I’ve responded to a few of your points below. I’ll leave the stratigraphic portion for Andrew to respond to if he chooses to here. Otherwise I’ve addressed your comments in chronological order.
Abstract – I agree that both of your comments here will make the paper better.
Introduction
-Exploration history of the Kayenta – I guess we were a bit unclear there. We were referring specifically to the concentrated paleontological exploration of the formation starting with Welles. We’ll clarify this in our next version.
Gold Tooth Spring is a spring near Moenkopi, just south of Highway 160. Having said that, this was a case of me mistyping this. We were meaning to refer to Gold Spring as you surmised.
Materials and Methods – I agree with your comments here.
Description – we feel very confident that these remains, scanty though they are, represent a single organism. While the span of time was three years all the material was recovered from the same bench in a 3 m X 5 m area. Preservation remains the same across all the specimens. Although the specimen is fragmentary there is no duplication. It might be trivial but it is still true. Limb elements would make this lack of duplication a stronger line of evidence, I admit. The fact that broken vertebrae collected from different areas of the exposure at different times also supports the idea that these all represent a single individual. Your point is well taken, however, that we need to better support this in the text and will do so in the next version.
Differential Diagnosis – I look forward to hearing your thoughts on what the elements are. As to identification of the elements we are looking at ways to more rigorously test their IDs. I understand and agree with your comments about using an apomorphy-based ID. As I mentioned above, we are confident this specimen represents a single individual.
Figures – I have my own concerns about the photos of the bones that arose after this preprint went live, some of which you mentioned in your comments. All the elements will likely be re-photographed and figures reworked in order to better present them.
Again, thanks for taking the time to look over the preprint and give your feedback. We appreciate it.
