Conodont Animal
Conodont body fossils are extremely rare but the tooth like elements are common. Complete element apparatuses also rare but they are known from several localities, even the best are preserved in a somewhat distorted mash. Complicated elements of the mouth collapse during decay leaving a confusing jumble of elements. Conodonts are abundant in the fossil record for about 340 million years varying in shape and assemblage. Conodonts were so diverse as a group that they are the ruling fossil group of the late Cambrian to the late Triassic marine environments. The diversity is in the elements also, there are literally thousands of element shapes representing many variations of the animal thought it’s history.
All the known apparatuses are made up of several kinds of up to 20 elements, coniform, ramiform and pectiniform blade and platform elements. Coniform elements were dominant in the Cambrian to Early Ordovician and common until the Devonian. Ramiforms were comb-like elements, and pentiniform elements were with straight or arched blades, some expanding laterally to form a platform. Conodont elements are calcium phosphate laminations covering a basal cavity. The basal cavity is capped by a large tooth-like projection termed the cusp, the cusp or cusps make up the elements. Conodont elements grew through the external addition of layers of apatite around the basal cavity, which suggests that the elements may have grown throughout the life of the animal. Since fossil localities containing complete apparatuses are rare, understanding of how they functioned is limited to available material.
Conodont elements were first described in 1856 by Heinz Christian Pander and it wasn't until 1982 that Euan N. K. Clarkson noticed the first conodont animal fossil while examining an old collection from the Granton Shrimp Beds. Conodont body fossils are extremely rare, there are only 4 localities known to preserve any soft tissue. Almost 10 complete body specimens are known from Scotland's Granton Shrimp Bed, still not much more than a dozen soft body fossils are known world wide. The best is Clydagnathus windsorensis from Scotland's Carboniferous, it has large eyes, a notochord and muscle bands running along a thin eel like body of about 1.5 inches or 4 cm. Specific structures of the mouth and the placement of the commonly found tooth like elements in the animal are open for debate and at best scientific speculation. Entire conodont element apparatuses are mostly preserved in a somewhat distorted mash, and through scientific analyses we can interpret them.
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Close examination of the some pentiniform elements shows scratched and chipped points of contact from grinding against one another, and some elements show pointed sheering or abrasive wear. This suggests that conodonts were specialized hunters and actively feeding on a variety of pray items, the simple act of closing its mouth would make escape improbable. Conodonts were actively hunted as well, elements have been found in a coprolite of a conodontophagous, as stomach contents of Typhloesus wellsi and in fish, such as Gogosardina a small fish that died with a conodont . Due to there size conodonts most likely were hunting in the planktonic column. Plankton was reduced several times in histories extinctions possibly contributing to the conodonts final demise much like the other fossil great the ammonite. Conodonts were chordates belonging to the superclass of Agnatha, a group of mostly extinct jawless fish. Modern Agnathans cannot regulate their own body temperature and they have metabolisms that are slow in cold water. They have no distinct stomach and do not have to eat very much, a hagfish may not eat for weeks. Conodonts are not a direct lineage as Hagfish have representatives in the fossil record from the same time period. Conodonts have been found in a variety of marine environments, shallow or nearshore to open water. The largest known conodont animal is Promissum pulcrum from the Ordovician Soom shale in South Africa. Promissum follows the standard body plan though it is significantly bigger, unfortunately only the front half was found. A total body length estimate of 40 cm was made by taking a 10 mm ramiform element from a Promissum and comparing it to a .76 mm ramiform element from a complete Granton body fossil. Conodonts only have a posterior tail and caudal fin much like a modern lamprey, and there mouth shape is undetermined with no direct fossil evidence and they had large eyes for there size. Even though Promissum had a larger body its eyes were proportionally smaller than other conodonts. This suggests that the conodont eye design reached it's maximum size before the body size of Promissum pulcrum. It is likely that the conodont animals 550 or so known genera, would have gone through many changes in there 340 million years of dominance, so we only have a small widow into there history.
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The conodont animal Clydagnathus windsorensis
from Scotland, with a close
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