Research at KPS

By Rick Schrantz

This section highlights the research with which the KPS is or has been involved. In some cases, a few members are studying a particular fossil or locality. In other cases, the KPS or a particular member has donated important fossils which are currently being studied by paleontologists at scientific institutions.

NEW CRINOID FOUND AND DONATED.—  In the June 2012 issue of Southeastern Geology, Paul Hearn and Brad Deline of University of West Georgia described a new crinoid called Paradiabolocrinus teres. The two specimens were collected and donated for study by member Rick Schrantz. They are from the Curdsville member of the Lexington Limestone, and are the only known specimens. They now reside in the Cincinnati Museum Center.

NEW PARACRINOID FOUND AND DONATED PLUS EDRIOASTEROID REDESCRIBED.—  In the January 2009 Journal of Paleontology, Colin Sumrall and Brad Deline of the University of Tennessee described a new species of paracrinoid called Bistomiacystis schrantzi. Member Rick Schrantz donated it for study, and it is the only known specimen. It now resides in the Cincinnati Museum Center. In addition to this paracrinoid, several specimens of the edrioasteroid Edrioaster priscus were donated by club president Dan Phelps and these specimens, due to their excellent preservation, allowed Colin and Brad to redescribe this animal as part of the same paper. These fossils were both found in the Curdsville member of the Lexington Limestone.

NEW MISSISSIPPIAN EDRIOASTEROIDS.— Two new edrioasteroids were discovered by the KPS in the Mississippian Borden Formation in west/central Kentucky, and specimens of them (at least 50) were donated by several members to the Cincinnati Museum Center. One was a new genus and species, and the other one was a new species. They have been described by Colin Sumrall (who, at the time, was the curator of invertebrate paleontology at the CMC), and the paper has been published in the Journal of Paleontology (January 2001) and in fact, was featured on the cover of the issue! One of the edrios has been named after the KPS. In the future, Colin may also publish a study of the Mississippian hardground on which they were found.

NEW RHOMBIFERAN.— A new rhombiferan (a type of cystoid echinoderm) has been discovered by KPS member Wallace White in east-central Kentucky in the Lower Silurian Brassfield Formation. It is a new species of the genus Anartiocystis. Both this complete specimen and an additional partial specimen (found by Rick Schrantz) were donated to the Cincinnati Museum Center. They have been described by Colin Sumrall, who was the museum's curator of invertebrate paleontology. The publication is the September 2002 Journal of Paleontology. The species was named after Wallace (Anartiocystis whitei).

RUSOPHYCUS (TRILOBITE BURROWS).— Dozens of Rusophycus (trilobite burrows) have been collected by the KPS from an outcrop of the Silurian Bisher Formation in n.e. Kentucky. They were made by a large trilobite, as the burrows can reach 6 inches long. The KPS thinks that this trilobite was Trimerus. One member (Dan Phelps) is currently studying these Rusophycus, because many of them intersect worm burrows. This may indicate that the trilobites were actively burrowing to catch worms for food. One specimen shows "struggle mark," which look very much like the trilobite was fighting to pull an uncooperative worm out of the mud. Another specimen clearly shows an abrupt bend in a trilobite trail towards a worm burrow. The trail then deepens into a trilobite burrow where it intersects the worm burrow. It looks very much like the trilobite spotted the worm, changed course, and dug a burrow to capture it.

BRACHIOSPONGIA.— KPS member Dan Phelps discovered a layer of the rare sponge Brachiospongia in an outcrop of Middle Ordovician Lexington Limestone (Curdsville Mbr.) in east-central Kentucky. Brachiospongia is a weird hexactinellid sponge with a central circular area and radiating "arms". Dan and other members are helping to excavate specimens. These are probably the oldest Brachiospongia ever found. Also, one specimen is about 15 inches in diameter, which would make it the largest ever found. It appears that these sponges were washed into a depressed area between raised hardgrounds. It also appears that crinoids lived among them. Dan believes that these specimens clearly show that two or more existing species are really the same animal exhibiting external and internal surfaces. A paper will likely be written about this. For images of Brachiospongia, visit this Kentucky Geological Survey page on sponges.

CYSTASTER EDRIOASTEROID.— KPS member Dan Phelps discovered a well preserved layer of Cystaster stellatus edrioasteroids in Boyle County, Kentucky in the Lexington Limestone (Sulphur Well Mbr.), which is Upper Ordovician. Frank Ettensohn at the University of Kentucky and his students subsequently excavated this layer and are in the process of describing it. Years after the excavation, a newly eroded gully of the same layer was exposed (by a 6-inch rainfall), and nearly 500 edrios have been recovered by excavation from this area. By now, the quarry has almost destroyed the collecting site. For images of fossils found at this locality, including Cystaster, see the Danville Field Trip. These edrios are preserved mostly on the brachiopod Rafinesquina on a limestone layer that varies in thickness from 2 inches to absent. The layer thickness can vary this much over only 4 or 5 feet distance. It is overlain by a layer of soft shale about 6 inches thick. There is no evidence of worm burrow damage on the edrios. The edrios are generally attached to the more abraded and worn looking brachiopods. The best preserved brachiopods will generally not have edrios attached. It appears that a storm event washed a lot of brachiopods into an area, but left them abraded. Edrios then colonized these brachiopod shells. A catastrophic burial event occured in which the edrios were likely buried alive. This event covered the layer deep enough with mud to preclude bioturbation. The thicker slabs from this layer (>1 inch) will generally have flattened, poorer preserved edrios on them with brachs that protrude only slightly above the surface. The best edrios come from slabs that are only 1/8 to 1/2 inch thick. The Rafinesquina project well above the surface of these thin slabs, and the Cystasters on them are possibly the best preserved ever found. The very best are attached to the apex of the convex brachiopod or a flat piece of brachiopod fragment. Edrios that were attached to the brachiopod near its margin were pushed down the convex slope of the brachiopod by the burial event, and are kind of squashed to one side. In addition to the brachiopods and edrios, the surface of the slabs is littered with fossil hash including trilobite fragments of Flexicalymene, Isotelus, and many Cryptolithus. There are also fragments of bryozoans, and an occasional worm tube and Cincinnaticrinus crinoid calyx. The lower side of one slab even has a Rusophycus.

PENTREMITES BLASTOIDS.— The KPS discovered and sent samples of an unusual blastoid to blastoid expert Dr. Johnny Waters (Chairman of the Geology Department at West Georgia, Carrollton, GA). They were found in Chesterian (Mississippian) shale in western Kentucky. We have collected at least 100 specimens of Pentremites that show an odd feature for which we can find no reference or illustration. It is a small stem-like feature extending up from the base of each radial plate. Both the KPS and Johnny Waters are fairly sure that it is a real structure, and not some sort of attached worm tube. Johnny has not seen this feature before and has no idea what it might be. The latest news we have from him is that he was going to attempt to section it to understand it better.

UPDATE 2012, PENTREMITES BLASTOIDS.—  In the September 2012 Journal of Paleontology, Will Atwood and Colin Sumrall described some Glen Dean blastoids, some from the same roadcut as above, which clearly showed the same mystery feature as illustrated in the KPS image ten years earlier. There was a lot of discussion and thin-sectioning of this feature, but it is still somewhat of a mystery. Will Atwood thinks it is a "pathology".....and clarifies as follows: "I don't believe that it is a birth defect because the smallest specimens don't show this feature. I say pathology for lack of other words. It would seem that if it wasn't a birth defect then it would affect all species at the locality but it doesn't. I would guess that it is a parasite but that is hard to swallow. I know there are species specific parasites but it still doesn't seem likely with very closely related species like this. I have seen a few specimens that have predatory bore holes but they are rare. If I can help with anything else just let me know."

SILURIAN TRILOBITES.— A KPS member (Todd Hendricks) is studying a deposit of Silurian trilobites from the Laurel Dolomite of north-central Kentucky. KPS members are familiar with our Bardstown Laurel collecting locality and the great trilobites found there. The other site Todd is studying promises to add to our understanding of this formation and how these trilobites became entombed there.