This is Mazon Monday post #284.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com.

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Mayomyzon pieckoensis is an extinct species of lamprey found in the Mazon Creek fossil biota. Pipiscius zangerli (see Mazon Monday #253) is also a lamprey from Mazon Creek.  Lampreys are a group of jawless fish known for its funnel-like sucking mouth. There are about 38 modern species with maybe 7 extinct species currently classified.  Genetic evidence suggests that lampreys are related to hagfish, another group of modern (and fossil) jawless fish.  The earliest known lampreys date to the Late Devonian of South Africa about 360 million years ago.

Mayomyzon pieckoensis was described in “First Fossil Lamprey: A Record from the Pennsylvanian of Illinois” by David Bardack and Rainer Zangerl. That paper was published in the jornal Science in 1968. Bardack studied fish at the Department of Biological Sciences, University of Illinois at Chicago Circle, Chicago.  He described many of the fishes of the Mazon Creek biota, including early hagfish and lamprey. Why, Zangerl was a Swuss paleontologist was a curator of fossil reptiles and later the geology department’s chair from 1945 until his retirement in 1974.  His specialty was fossil sharks.

Mayomyzon pieckoensis was named for Ted and Helen Piecko.  Helen Piecko and her son Ted have no less than 6 species of Mazon animals named for them, including Pieckonia helemae and  Octomedusa pieckorum.  The “May” in Mayomyzon refers to Stephen LaMay.

Jack Wittry discusses Mayomyzon pieckoensis on page 125 of his “The Fossil Fauna of Mazon Creek”.

Mayomyzon pieckoensis Bardack and Zangerl, 1968

Lampreys are the most primitive of all chordates. These agnathan animals are characterized by having uncalcified skeletons with no bony tissue and jawless mouths. Mayomyzon pieckoensis, like all lampreys, is a long, very slender, eel-shaped fish, ranging in length from about 30 mm to 60 mm and approximately 6 mm in width. The mouth appears as a slanting line at the lower anterior of the body. In a lateral view, the large eye is a dark stain against a lighter body. The gill pouches are shown as stains in an area behind and below the eye. A few specimens have continuous dorsal, anal, and caudal fins. Cartilage is indicated by a lighter stain in the head region. A color differentiation in the body cavity outlines what is believed to be the heart and liver. The digestive tract forms a long dark line from the gill pouches to the dorsal fin.

When M. pieckoensis was described in 1968, it was the only lamprey in the fossil record. Since then, an older specimen from Bear Gulch, Montana, extends the range of the lamprey back to the Mississippian. The many similarities between modern and fossil lampreys suggest that they are a conservative group. They were likely bottom-dwellers capable of freely swimming. Their diet is unknown, though it is possible they were parasitic and may have also consumed small invertebrates or detritus. M. pieckoensis is found in the marine Essex Fauna of Pit 11.

David Bardack wrote chapter 17 “Fishes” for the “Richardson’s Guide to the Fossil Fauna of Mazon Creek”.

Order Petromyzontiformes
Mayomyzon pieckoensis Bardack and Zangerl

This order includes the living lampreys (sometimes called “lamprey eels” but not related to true eels), some of which are confined to freshwater, while others spend part of their lives at sea before returning to freshwater for spawning These are elongate fishes, the adults of which show large round mouths containing horny teeth. There are a number of separate gill openings. The skeleton is cartilaginous. The fossils are generally similar to living lampreys but differ 1) in the apparent absence of a large buccal (mouth) funnel, 2) in the lack of dentition, 31 in the position of the otic (ear) capsule, which lies above the first and second gill pouches, 4) in the position of the gill pouches, which, when viewed from above, extend at nearly a right angle to the body axis, and 5) in the otic capsule’s not being in contact with the braincase (Bardack and Zangerl, 1971; Bardack, 1979). More than two dozen specimens have been assigned to M. pieckoensis. All are small, measuring less than 8 cm in total length. Some of the differences between the fossils and living adult lampreys (e.g., items 1, 2, and 3 above) suggest that these fossils may be in a juvenile rather than adult stage of development. Typical adult characters, especially the buccal dentition so important in distinguishing living forms, may not be preserved, may be too small to recognize, or may form later in ontogenetic (individual) or phylogenetic (evolutionary) development. However, the large eyes, well-developed gill chambers, and large piston cartilage (part of the unique feeding feature of lampreys) implies an adult stage. All specimens are from the Essex fauna. However, it remains a possibility that these lampreys spent part of their life history in freshwater coal swamps or that these small, possibly late larval forms were swept into the brackish marine water area of the Mazonian delta from freshwater where eggs may have been laid and underwent early development as in the case of living sea lampreys. There is one other fossil lamprey (Janvier and Lund, 1983), which differs somewhat from Mayomyzon especially in the caudal fin. This fossil from the Mississippian marine sediments of the Bear Gulch Limestone of Montana is not as well preserved in the head region as Mayomyzon.

Specimens

Field Museum PF 5687, which is the holotype.  Found in Pit 11

From Wittry’s “The Fossil Fauna of Mazon Creek”