Grundy County is a county in the U.S. state of Illinois. According to the 2020 census, it has a population of 52,533. Its county seat is Morris.
Mazon is a village in Mazon Township, Grundy County, Illinois, United States. The name derives from the Potawatomi word for "nettles" (mzan). The population was 979 at the 2020 census. Illinois' State Fossil, the unique and bizarre Tully Monster was first found in nearby Mazon Creek. Mazon was formerly served by the Santa Fe railway at the Mazon Depot. It was established in 1876.
Tullimonstrum, colloquially known as the Tully monster or sometimes Tully's monster, is an extinct genus of soft-bodied bilaterian animal that lived in shallow tropical coastal waters of muddy estuaries during the Pennsylvanian geological period, about 300 million years ago. A single species, T. gregarium, is known. Examples of Tullimonstrum have been found only in the Essex biota, a smaller section of the Mazon Creek fossil beds of Illinois, United States. Its classification has been the subject of controversy, and interpretations of the fossil have likened it to molluscs, arthropods, conodonts, worms, tunicates, and vertebrates. This creature had a mostly cigar-shaped body, with a triangular tail fin, two long stalked eyes, and a proboscis tipped with a mouth-like appendage. Based on the fossils, it seems this creature was a nektonic carnivore that hunted in the ocean’s water column. When Tullimonstrum was alive, Illinois was a mixture of ecosystems like muddy estuaries, marine environments, and rivers and lakes. Fossils of other organisms like crustacean Belotelson, the cnidarian Essexella, and the elasmobranch fish Bandringa have been found alongside Tullimonstrum.
The Mazon Creek fossil beds are a conservation lagerstätte found near Morris, in Grundy County, Illinois. The fossils are preserved in ironstone concretions, formed approximately 309 million years ago in the mid-Pennsylvanian epoch of the Carboniferous period. These concretions frequently preserve both hard and soft tissues of animal and plant materials, as well as many soft-bodied organisms that do not normally fossilize. The quality, quantity and diversity of fossils in the area, known since the mid-nineteenth century, make the Mazon Creek lagerstätte important to paleontologists attempting to reconstruct the paleoecology of the sites. The locality was declared a National Historic Landmark in 1997.
The Mazon River or Mazon Creek, is a tributary of the Illinois River in the United States. The confluence is near Morris, Illinois.
Pohlsepia mazonensis is a species of fossil organism with unknown affinity. Although it was originally identified as an extinct cephalopod, later studies denied that interpretation. The species is known from a single exceptionally preserved fossil discovered in the late Carboniferous (Pennsylvanian) Francis Creek Shale of the Carbondale Formation, north-east Illinois, United States.
Helenodora is an extinct basal onychophoran or lobopodian genus known from the Carboniferous Carbondale Formation of Illinois. The only known species described is H. inopinata. The ecology of this animal is not well known, but it is thought that it may have lived on land and/or underwater.
Carrolla is an extinct genus of brachystelechid 'microsaur' that lived in the Lower Permian in North America. It was named in 1986 by American paleontologists Wann Langston and Everett Olson. The type species, Carrolla craddocki, is the only known species.
Odonterpeton is an extinct genus of "microsaur" from the Late Carboniferous of Ohio, containing the lone species Odonterpeton triangulare. It is known from a single partial skeleton preserving the skull, forelimbs, and the front part of the torso. The specimen was found in the abandoned Diamond Coal Mine of Linton, Ohio, a fossiliferous coal deposit dated to the late Moscovian stage, about 310 million years ago.
Illiniichthys is an extinct genus of prehistoric bony fish that lived during the late Moscovian stage of the Pennsylvanian epoch in what is now Illinois, United States. Fossils were collected from the Mazon Creek fossil beds. The genus is named after the Illini Native American tribe.
Nozamichthys is an extinct genus of prehistoric bony fish that lived during the late Moscovian stage of the Pennsylvanian epoch in what is now Illinois, United States. Fossils were collected from the Mazon Creek fossil beds. The first part of the genus name is Mazon spelled backwards, and the second part means 'fish'.
Brachystelechidae is an extinct family of Early Permian microsaurs. The family was first named by Robert L. Carroll and Pamela Gaskill in 1978, with the only member being Brachystelechus fritschi. Brachystelechus fritschi has since been reassigned to the genus Batropetes. Genera assigned to the family include: Batropetes, from Germany; Carrolla, from Texas; Quasicaecilia, also from Texas; Diabloroter, from the Mazon Creek lagerstätte of Illinois; and Bromerpeton from the Tambach Formation of Germany.
Cephalerpeton is an extinct genus of "protorothyridid" tetrapods known from the Late Carboniferous of Illinois.
Recumbirostra is a clade of tetrapods which lived during the Carboniferous and Permian periods. They are thought to have had a fossorial (burrowing) lifestyle and the group includes both short-bodied and long-bodied snake-like forms. At least one species, the long-bodied molgophid Nagini mazonense, lost its forelimbs entirely. Recumbirostra includes the families Pantylidae, Gymnarthridae, Ostodolepidae, Rhynchonkidae and Brachystelechidae, with additional families such as Microbrachidae and Molgophidae being included by some authors. Brachystelechidae and Molgophidae have also been grouped together in the suggested clade Chthonosauria.
Spondylerpeton is an extinct genus of embolomere closely related to "Cricotus" (Archeria) in the family Archeriidae. This genus is known from fragmentary remains, namely a short series of tail vertebrae preserved in an ironstone nodule. These remains were found in the Mazon Creek beds of Illinois, an area famed for its preservation of Carboniferous plants and animals. Spondylerpeton individuals were probably about three to four feet in length, by far the largest animals known to have inhabited the Mazon Creek area during this era.
Diabloroter is a Carboniferous genus of brachystelechid 'microsaur' from the Mazon Creek lagerstätte in Illinois. It was named in 2019 by Arjan Mann and Hillary C. Maddin.
Infernovenator is a genus of Carboniferous lysorophian recumbirostran from the Mazon Creek lagerstätte in Illinois, U.S. It was described in 2019.
Bandringa is an extinct genus of elasmobranch known from the Pennsylvanian subperiod of the Carboniferous period that was part of the monotypic family Bandringidae. There is currently a single known species, B. rayi, described in 1969. It is known from exceptionally preserved individuals found in the Mazon Creek Lagerstätte of Illinois which dates back to the late Moscovian stage.
Nagini is an extinct genus of recumbirostran tetrapods from the middle Carboniferous of the Mazon Creek fossil beds, Illinois, United States. The type and only species, Nagini mazonense, was named by Arjan Mann and colleagues in 2022 from two specimens, both of which preserve soft tissue like other fossils from Mazon Creek: MPM VP359229.2 and FMNH PR 1031. It is a member of the Molgophidae, a lineage of amniote-like tetrapods which exhibited a pattern of body elongation and digit reduction on the limbs. Nagini is the first member of the group that shows the complete loss of the forelimbs and pectoral girdle, but it still has intact hindlimbs; this mirrors the pattern seen in the evolution of snakes, and suggests that molgophids underwent a similar mechanism of limb reduction beginning with the failure to form distinct forelimbs.
