Sunday, November 25, 2012

H.C. Pander and strange Conodonts

Heinz Christian Pander (1794-1865)
Latvian German biologist Heinz Christian Pander (1794-1865) studied among other things chick embryos. Because of his advanced researches Pander is called the Father of Embryo studies and he was made member of St. Peterburg's Academy of Sciences in 1825.

H.C. Pander worked in his home in Carnikava by the Gauja-river near Riga. At that time English naturalists were taking major steps advancing geology. Pander knew about the subject and in addition to embryos was interested also in "the beginning of life".  In 1820 he had taken part in at that time a rather dangerous research expedition to Bukhara, Persia.

Three types of conodont
Mauch Chunk formation, Carboniferous
Heinz Christian Pander is the first one to report strange spiny objects in sedimentary rock. As a son of Adam he gave these curious items scientific name conodont (kr. konos odont, conical tooth).

Conodonts remained a scientific mystery for 150 years. They were known from many rock sediments around the world but what are they, remains of some kind of living things, just mineral formations, pieces of coral? There was no certainty about any of these theories in the lack of evidence beyond the strange conodont micro-fossils.

Only in 1980 did Adam find the answer. By the grace of God he found a Nature Reserve in South Africa where conodont were found connected to the head of an animal. While apparently fairly common in prehistoric oceans the soft tissues of the animal have disappeared and only the hard tooth-like elements survived. Today scientists know only 11 well-preserved samples of conodont.

Working on Soom shale
Kuva courtesy of Prof. Richard Aldridge & Dr Sarah Gabbott, University of Leicester, UK
One of the locations where conodont remains have survived is in South Africa. The 10-15 m thick Soom shale, Cederberg formation, is in Table Mountain near Cape Town and is dated to Ordovician period well before Devonian (the entire formation is amazing 120 meters thick).

The animals found are rather short, often only one cm or so, but a huge 40 cm long specimen has been found in Soom shale. Adam called it Promissum pulcrum. See for example Johannes N. Theron 1992 report of an Upper Ordocivian konservat-lagerstätte in the Journal of Micropalaeontology.

Photo Winneshiek lagerstätte
Huaibao P. Liu, Robert M. McKay ja Brian J. Witzke describe a discovery of the Winneshiek lagerstätte in Decorah, Iowa. The pages have illustrations of the work and discoveries, one of which I copied here. The beast looks quite scary - until you double check the scale.

Today conodont is better known. It is jawless but inside the head is an arrangement of tooth-like elements consistingn of 15 or 19 tooth. It had two eyes in front of the head, fin to help in swimming and a skeleton like notochord (chick embryos studied by Pander also have a notochord).

Without a jaw cocodont did not bite its food. Instead, plankton entered its open mouth while it was swimming and the tooth-arrangement crushed it for digestions. Conodont did not have muscles to gain speed for attack and was probably not an active hunter.

Conodont wikimedia
As we ponder the background of Devonian fish we need to keep in mind conodont that appears already in Late Cambrian.

It is not a fish, not a bird, not a frog ... it is a conodont named by H.C. Pander.

It is no more. Conodont fossils are not found after the evening that ended Triassic. But it was a very successful creature existing on planet Earth for over 300 million human years.

Eel looks a bit like conodont but is a real fish
Image Jon Staple

No comments:

Post a Comment