Gastropods / Monoplacophorans from the Permian Fort Apache Limestone East of Payson

Updated  10/16/17

 By far, the largest project in the Fort Apache Limestone series! We found more tiny gastropods than any other type of fossils in the acid fines. Literally thousands and thousands of pinhead sized gastropods and monoplacophorans were found, and after months of picking through the residues, we had several teaspoons of the microscopic fossils. The sorting process took weeks and we decided to sort them according to morphological type. This yielded 22 different varieties, some of which may have been duplicates that were preserved different or incompletely. Fortunately for us, Winters in his huge GSA 89 monograph identified scores of gastropods making many of the identifications possible for us. We also found several types which he did not show or mention.

The conclusions that can be drawn from our gastropods is still clear - a very muddy bottom which preserved huge numbers of juveniles either because of inclement conditions for their survival or a high mortality rate. The preservation ranges from very poor to superb. Many of the smallest fossils show amazing details in their outer shells and large numbers of ornamented types were uncovered. The most common type was the small squat cones, ten times more common than any other type. They were also the very smallest to be found as well.

Images Section:

Bellerophon sp. - Monoplacophoran

There is considerable controversy as to where Bellerophon resides in the mollusk group. Latest papers seem to indicate that it is about half way from the limpet shaped basal primitive monoplacophorans and the accepted standard gastropod. No one has ever found fossils of their soft anatomy, and until this occurs, they will remain an enigma.

  Top view showing dorsal ridge
Another specimen with a very prominent dorsal median ridge.

Underside showing pointed lip at top typical of Bellerophontids.
Low angle of same specimen showing ribbing to the right of the dorsal ridge.
Ribbed Cones (Paleostylus giganticus)
7x view of many specimens of this uniquely ornamented high spired gastropod.
30x close up showing the angled linear ribbing.
Spiral Double Rib Cones (Genus et species. indet.)
Winters missed these!
30x close up
Honey Buns (Apachella prodontia)
10x view of a nice collection of bun shaped gastropods with a unique proto conch region.
Long Ribbed Cones (Goniasma terebra)
7x view of various specimens with varying preservation.
Globose shells (Naticopsis apachensis)
Oh so rare, this wonderful globe shaped gastropod is similar to "Nautica" of today. 
another view of lower specimen.
Ornamented Rimmed Buns (Worthenia arizonensis)
  Fantastic ornamentation on these!
  Bottom view
20x close up of proto conch and square ribs.
Ornamented Tall Buns (Worthenia arizonensis)
More magnificent specimens with good ornamentation.
Close up of the one specimen that is stuck to a small oblong clam.
Ornamented Cones (Genus et species. indet.)
  7x Winters found these but was unable to identify them.
  20x type 1
15x type 2
Spiral Squat Cones (Apachella prodontia)
  15x - very common type found with most of them missing the bottom big whorl.
Pupae Shaped (Genus et species. indet.)
Another one Winters did not find on the reservation.
10x of nice group
Ridged Cones (Goniasma terebra)
7x - depending on the preservation, the ribbing on these will appear textured or worn smooth.
Ribbed Bellerophon shaped Gastropods (Knighties modestus)
  These look very much like a Bellerophon but they do not have the same fine features defining that group. They are much smaller too, pin head sized.
  Gorgeous ribbing along their spirals
Not a dorsal ridge like Bellerophon but a similar feature.
Ribbed Snails (Apachella arizonensis)
Maybe unique to Arizona?
15x view
Smooth Cones (Various eroded species)
  7x Many cones were so worn that we could not positively identify them.
  A few more
This one was quite interesting in preservation, completely crystallized in white quartz.
Smooth Bellerophon shaped Gastropods (Knighties sp.)
Another Bellerophon look a like.
Largest specimen found was attached to other fossils
Smooth Snails (Apachella sp.)
Very smooth exterior
Quite a few of this type found!
Squat Ridged (Genus et species. indet.)
Very bold ribbing
Not found by Winters either.
Tall Spired Turriculate (Genus et species. indet.)
This is one of the most interesting gastropods we find. The beautiful tall spirals are stunning.
Winters does not show these, he missed a really nice gastropod here!
Tiny Squat Juvenile Cones (Variety of juveniles)
Zig Zag Ribbed (Glyptospira cristulata)
Certainly one of the most beautiful gastropods we find.
The ornamentation is stunning.
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