Cnidarians (Corals) Lophamplexus sp. from the Permian Fort Apache Limestone East of Payson

Updated  10/31/17

 Ten times rarer than trilobites, rugose corals are a very small part of the Fort Apache Sea benthic community. We only found one specimen in over 230 pounds of limestones that went into the acid bath. And its a small one - not even 1 centimeter in length. But its cnidarian features are unmistakable. Winters in his monumental monograph on the Fort Apache Fossils (GSA Memoir 89) found a very similar coral, in fact it appears to be identical to his photos - Lophamplexus sp. In addition to this rare coral find, just inside the calice was a coiled microconchid tube, which cemented itself to the coral after it had expired and was an empty husk lying on the sea bottom.

Why corals are so rare goes along with the missing crinoids, blastoids, sponges and brachs. The bottom of the Fort Apache Sea was filled with gooey muck from settled silt and sand from the nearby Schnebly Aeolian dune field. With a constant rain of such fine material, the filter feeding mechanisms of such animals would not function properly and get clogged. So only silt tolerant organisms are found here.

All images with an AmScope Trinocular microscope, 10mp camera and stacked with focus stacking software - Picolay. (free!)

 Lophamplexus sp. - 7x. Side view showing detail in the crenelations and bands on the exterior.

 Lophamplexus sp. with the microconchid tube on the left edge inside. 7x. You can see the septa defining the corals calice as ridges on the inside wall.

 Lophamplexus sp. This Close up at 20x shows the interior is filled with essentially sand that has been cemented together along with the coiled microconchid with its open tube on the lower left inside. The tube worm lived by cementing itself to a flat hard surface for an anchor. We have found plenty of them attached to urchin spines, shells and bryozoans. (Think similar to modern feather duster marine worms).

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