"Isotelus Site"

[Fullux]

Howdy all,

 

This is a snippet from a record I'm keeping while I pursue paleontology as a career and I'm wondering what y'all think of it.

 

 

I have had several opportunities to find fossils in many different deposits of the Drakes Formation within the Broad Run Park area. I have particularly been interested in the genus isotelus, a gargantuan trilobite and what is in my opinion one of the more fascinating of Kentucky’s paleofauna. On July 13th of this year (2024) I stumbled upon a site I had not seen before. What stuck out to me about this site was the size and quality of dozens of isotelus molt fragments, many of which were diagnostic. In contrast, the other deposits I have visited in the area bear few, tiny fragments which cannot be assigned to any particular part of the trilobite’s exoskeleton.

I have visited this site four times since I found it (Today being July 23rd) and have continued to find excellent specimens. On today’s expedition, I found my second and most complete hypostome to an isotelus, and before today have managed to find pieces of the cephalon/pygidium, thorax segments, and yet another hypostome. Another thing that has more recently stuck out to me is the sessile benthic fauna. At this site, I have found countless rugose corals and bryozoans, but there is no evidence whatsoever of tabulate corals. In contrast, at another site I have visited, I found small, half pound tabulate corals all the way up to giant twenty five pound ones. I have managed to find only a few, very small, fragmentary pieces of isotelus in this site.

Considering all these things, it makes me wonder if, either this represents different “biomes,” or if this shows how the environment of the Drakes changed over time, assuming these sites are of different layers.

For example, the biome at the “isotelus site” would persist of a flat, mostly open seabed covered in rugose corals and bryozoans, where isotelus would frequent, and the “tabulate coral site” would persist of a reef environment with a diverse community of corals and bryozoans where isotelus would not frequent.

It is worth noting that nautiloids are present in both sites. Not surprising, as nautiloids have been shown to be very adaptable over the course of their existence on this planet.

 

Another interesting thing I have been thinking about, in regards to the aforementioned hypostomes, is the fact that there is a great variation in the length of their prongs. The first one I found is not a good example, as it is missing one prong and the other is missing its tip. The other I found today, however, preserves both prongs, which are quite long when compared to others I have seen in other people’s collections. I am curious if this could represent different ages in isotelus, where the prongs get gradually longer as the trilobites get older, or if this could represent social behavior/sexual dimorphism and or implements. Perhaps males had longer prongs than females, which would be used for sexual combat, or vice versa.