''Mazonova'' is an
oogenus
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...
of
fossilized eggs from the
Mazon Creek
The Mazon Creek fossil beds are a conservation ' found near Morris, in Grundy County, Illinois. The fossils are preserved in ironstone concretions, formed approximately in the mid- Pennsylvanian epoch of the Carboniferous period. These concreti ...
area in the
Pennsylvanian of
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...
. They are laid in long strings of eggs enclosed in a gelatinous sheath containing one or two rows of eggs. It is unknown what kind of animal laid the eggs.
[Godfrey, S.J. (1995). "Fossilized Eggs from the Pennsylvanian of Illinois." ''Ichnos: an international journal for plant and animal traces.'' 4(1):71-75.]
Description
''Mazonova'' is known from seven specimens. They are represented by fossilized impressions of long strands of eggs encased in a gelatinous sheath. In some specimens, the eggs are paired, whereas others have only a single row. The eggs are 1.5 to 1.7 mm in diameter, and the sheath is 3.0 to 3.8 mm in diameter.
[
]
Classification
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
eggs are rare in the fossil record. Some coelacanth
The coelacanths ( ) are fish belonging to the order Actinistia that includes two extant species in the genus ''Latimeria'': the West Indian Ocean coelacanth (''Latimeria chalumnae''), primarily found near the Comoro Islands off the east coast ...
eggs (belonging to '' Rhabdoderma exiquum'') are known, as well as the eggs of sharks, but ''Mazonova'' is quite distinct. They closely resemble the strands of eggs laid by some modern fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
and amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s, as well as opisthobranch
Opisthobranchs () is now an informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping.
Euopisth ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
s. However, the eggs are far too large to be mollusk eggs, indicating they represent eggs of a vertebrate, though it is impossible to assign them to any order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
. There are several fish and amphibians from the Mazon Creek that could have spawned ''Mazonova''.[
]
References
Carboniferous amphibians of North America
Pennsylvanian fish of North America
Fish reproduction
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