Erik Jarvik
Encyclopedia
Anders Erik Vilhelm Jarvik (30 November 1907 – January 11, 1998) was a Swedish
palaeozoologist
who worked extensively on the sarcopterygian
(or lobe-finned) fish Eusthenopteron
. In a career that spanned some 60 years, Jarvik produced some of the most detailed anatomical work on this fish, making it arguably the best known fossil vertebrate.
Jarvik was born at a farm in Utby
in Västergötland
. He studied botany
, zoology
, geology
, and paleontology
at Uppsala University
, where he took his licentiate
's degree in 1937. In 1942, he completed his PhD with the dissertation On the structure of the snout of Crossopterygians and lower Gnathostomes in general. He participated in the Greenland expedition of Gunnar Säve-Söderbergh
in 1932 and was appointed assistant in the Department of Palaeozoology of the Swedish Museum of Natural History
in Stockholm
in 1937; he eventually succeeded Erik Stensiö
as professor and head of the department in 1960, retiring in 1972.
fishes. His main interests were in the so-called "rhipidistian"
sarcopterygian fishes, which he held to be divided into two groups: the Osteolepiformes and the Porolepiformes
. He published several solidly descriptive works on Devonian sarcopterygians.
and applied to fossil fishes by Erik Stensiö
. A fossil of limited external quality was sectioned by grinding off a thin section, photographing the grind-off end and repeat the process until the whole fossil was worked through. The internal structures would then show up on long series of photographs. Working in the day before computer simulations, models was made by projecting reversal film on a board, and cut thin wax
plates to match. The sticky wax plates could then be assembled to a 3 dimensional scaled up model of the skull, complete with internal structures such as nerve channels and other internal hollows rarely seen in fossils. Further section to the cranium could easily be made by cutting the wax model at the desired angle. Due to the sticky nature of the wax used, a sectioned skull was put back together by simply pressing the two sections back together. This technique was also applied to the cranium of the porolepiform Glyptolepis groenlandica.
possibly excepted – were descended from primitive osteolepiforms. Thus Amphibia had arisen twice.
On the basis of his findings, he argued that Amphibia should be split, with salamanders (and possibly caecilians) in one class (the Urodelomorpha), and the frogs as a separate class, the Batrachomorpha
. The Lepospondyli
was thought as possible Urodelomorphans, while the other Labyrinthodonts were thought to be Batracomorphs. Jarviks ideas was never widely accepted, though Friedrich von Huene
did include his system in systematic treatment og tetrapods. Few other supported his ideas, and today it has been abandoned by vertebrate paleontologists. The term "Batrachomorpha" is however sometimes used in an cladistic
sense to denote Labyrinthodonts more closely related to modern amphibians than to amniote
s.
which he held to be relatively primitive gnathostomes, possibly related to holocephalans, and of acanthodians
, which he considered to be elasmobranchs rather than osteichthyans. He made contributions to a number of classical problems in comparative anatomy, including the origin of the vertebrates the origin of the pectoral and pelvic girdles and paired fins, and the homologies of the frontal and parietal bones in fishes and tetrapods
Finally, Jarvik investigated the anatomy of Ichthyostega
, resulting in a monograph with an extensive photographic documentation of the material collected in 1929-1955.
and French Academy of Sciences
and Knight of the Order of Vasa
. The lungfish Jarvikia and the osteolepiform Jarvikina are named after him.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
palaeozoologist
Paleozoology
Paleozoology, also spelled as palaeozoology , is the branch of paleontology or paleobiology dealing with the recovery and identification of multicellular animal remains from geological contexts, and the use of these fossils in the reconstruction of prehistoric environments and ancient...
who worked extensively on the sarcopterygian
Sarcopterygii
The Sarcopterygii or lobe-finned fishes – sometimes considered synonymous with Crossopterygii constitute a clade of the bony fishes, though a strict classification would include the terrestrial vertebrates...
(or lobe-finned) fish Eusthenopteron
Eusthenopteron
Eusthenopteron is a genus of prehistoric lobe-finned fish which has attained an iconic status from its close relationships to tetrapods. Early depictions of this animal show it emerging onto land, however paleontologists now widely agree that it was a strictly aquatic animal...
. In a career that spanned some 60 years, Jarvik produced some of the most detailed anatomical work on this fish, making it arguably the best known fossil vertebrate.
Jarvik was born at a farm in Utby
Utby
Utby is a locality situated in Uddevalla Municipality, Västra Götaland County, Sweden with 219 inhabitants in 2005....
in Västergötland
Västergötland
', English exonym: West Gothland, is one of the 25 traditional non-administrative provinces of Sweden , situated in the southwest of Sweden. In older English literature one may also encounter the Latinized version Westrogothia....
. He studied botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, zoology
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
, geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, and paleontology
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
at Uppsala University
Uppsala University
Uppsala University is a research university in Uppsala, Sweden, and is the oldest university in Scandinavia, founded in 1477. It consistently ranks among the best universities in Northern Europe in international rankings and is generally considered one of the most prestigious institutions of...
, where he took his licentiate
Licentiate
Licentiate is the title of a person who holds an academic degree called a licence. The term may derive from the Latin licentia docendi, meaning permission to teach. The term may also derive from the Latin licentia ad practicandum, which signified someone who held a certificate of competence to...
's degree in 1937. In 1942, he completed his PhD with the dissertation On the structure of the snout of Crossopterygians and lower Gnathostomes in general. He participated in the Greenland expedition of Gunnar Säve-Söderbergh
Gunnar Säve-Söderbergh
Gunnar Säve-Söderbergh was a Swedish palaeontologist and geologist. Säve-Söderbergh was born at Falun, the son of the neurologist Gotthard Söderbergh and Inga Säve. He passed his G.C.E. at Gothenburg in 1928 and took bachelor's and licentiate's degrees at Uppsala University in 1931 and 1933,...
in 1932 and was appointed assistant in the Department of Palaeozoology of the Swedish Museum of Natural History
Swedish Museum of Natural History
The Swedish Museum of Natural History , in Stockholm, is one of two major museums of natural history in Sweden, the other one being located in Gothenburg....
in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
in 1937; he eventually succeeded Erik Stensiö
Erik Stensiö
Erik Helge Osvald Stensiö was a Swedish paleozoologist.Erik Andersson, as his original name was, was born in the village of Stensjö in Döderhult parish in Kalmar County; he later took his new surname from his place of origin and is occasionally referred to with both names...
as professor and head of the department in 1960, retiring in 1972.
Research
Jarvik's research concerned mainly the sarcopterygianSarcopterygii
The Sarcopterygii or lobe-finned fishes – sometimes considered synonymous with Crossopterygii constitute a clade of the bony fishes, though a strict classification would include the terrestrial vertebrates...
fishes. His main interests were in the so-called "rhipidistian"
Rhipidistia
The Rhipidistia were lobe-finned fishes that are the ancestors of the tetrapods. Taxonomists traditionally considered the Rhipidistia a subgroup of Crossopterygii that described a group of fish that lived during the Devonian consisting of the Porolepiformes and Osteolepiformes...
sarcopterygian fishes, which he held to be divided into two groups: the Osteolepiformes and the Porolepiformes
Porolepiformes
Porolepiformes is an order of prehistoric lobe-finned fish which lived during the Devonian period . The group contains two families: Holoptychiidae and Porolepididae....
. He published several solidly descriptive works on Devonian sarcopterygians.
Work on Eusthenopteron
In particular, he conducted detailed anatomical studies of the cranium of Eusthenopteron foordi using a serial-section technique introduced by William Johnson SollasWilliam Johnson Sollas
William Johnson Sollas FRS was a British geologist and anthropologist. After studying at the City of London School, the Royal College of Chemistry and the Royal School of Mines he matriculated to St. John's College, Cambridge, where he was awarded First Class Honours in geology...
and applied to fossil fishes by Erik Stensiö
Erik Stensiö
Erik Helge Osvald Stensiö was a Swedish paleozoologist.Erik Andersson, as his original name was, was born in the village of Stensjö in Döderhult parish in Kalmar County; he later took his new surname from his place of origin and is occasionally referred to with both names...
. A fossil of limited external quality was sectioned by grinding off a thin section, photographing the grind-off end and repeat the process until the whole fossil was worked through. The internal structures would then show up on long series of photographs. Working in the day before computer simulations, models was made by projecting reversal film on a board, and cut thin wax
Wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
plates to match. The sticky wax plates could then be assembled to a 3 dimensional scaled up model of the skull, complete with internal structures such as nerve channels and other internal hollows rarely seen in fossils. Further section to the cranium could easily be made by cutting the wax model at the desired angle. Due to the sticky nature of the wax used, a sectioned skull was put back together by simply pressing the two sections back together. This technique was also applied to the cranium of the porolepiform Glyptolepis groenlandica.
Theories on amphibian phylogeny
Jarvik proposed partly controversial hypotheses about the principal structure of the vertebrate head and the origin of the tetrapods. He thus held, on the basis of detailed analyses of the snout and nasal capsule structures as well as the intermandibular, neuroepiphysial, and occipital regions, that Tetrapoda was biphyletic. In his view, the anatomical details of the Caudata (salamanders) bound them to the primitive porolepiform fishes, while all other tetrapods (“eutetrapods”) – apodansCaecilian
The caecilians are an order of amphibians that superficially resemble earthworms or snakes. They mostly live hidden in the ground, making them the least familiar order of amphibians. All extant caecilians and their closest fossil relatives are grouped as the clade Apoda. They are mostly...
possibly excepted – were descended from primitive osteolepiforms. Thus Amphibia had arisen twice.
On the basis of his findings, he argued that Amphibia should be split, with salamanders (and possibly caecilians) in one class (the Urodelomorpha), and the frogs as a separate class, the Batrachomorpha
Batrachomorpha
Batrachomorpha is a name traditionally given to recent and extinct amphibians that are not related to reptiles. It most often includes the extinct groups Temnospondyli and Lepospondyli.-Origin of the term:...
. The Lepospondyli
Lepospondyli
Lepospondyli are a group of small but diverse Carboniferous to early Permian tetrapods. Six different groups are known, the Acherontiscidae, Adelospondyli, Aïstopoda, Lysorophia, Microsauria and Nectridea, and between them they include newt-like, eel- or snake-like, and lizard-like forms, along...
was thought as possible Urodelomorphans, while the other Labyrinthodonts were thought to be Batracomorphs. Jarviks ideas was never widely accepted, though Friedrich von Huene
Friedrich von Huene
Friedrich von Huene was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe.-Biography:...
did include his system in systematic treatment og tetrapods. Few other supported his ideas, and today it has been abandoned by vertebrate paleontologists. The term "Batrachomorpha" is however sometimes used in an cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
sense to denote Labyrinthodonts more closely related to modern amphibians than to amniote
Amniote
The amniotes are a group of tetrapods that have a terrestrially adapted egg. They include synapsids and sauropsids , as well as their fossil ancestors. Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes...
s.
Lungfish phylogeny
Jarvik also studied the anatomy and relationships of lungfishLungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
which he held to be relatively primitive gnathostomes, possibly related to holocephalans, and of acanthodians
Acanthodii
Acanthodii is a class of extinct fishes, sharing features with both bony fish and cartilaginous fish. In form they resembled sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteans...
, which he considered to be elasmobranchs rather than osteichthyans. He made contributions to a number of classical problems in comparative anatomy, including the origin of the vertebrates the origin of the pectoral and pelvic girdles and paired fins, and the homologies of the frontal and parietal bones in fishes and tetrapods
Finally, Jarvik investigated the anatomy of Ichthyostega
Ichthyostega
Ichthyostega is an early tetrapod genus that lived at the end of the Upper Devonian period . It was a labyrinthodont, one of the first fossil record of tetrapods. Ichthyostega possessed lungs and limbs that helped it navigate through shallow water in swamps...
, resulting in a monograph with an extensive photographic documentation of the material collected in 1929-1955.
Legacy
Some of Jarvik’s views did not accord with general opinion in vertebrate paleontology. However, his anatomical studies of Eusthenopteron foordi laid the foundations for modern studies of the transition from fishes to tetrapods. Jarvik was a member of the Royal Swedish Academy of SciencesRoyal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
and French Academy of Sciences
French Academy of Sciences
The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research...
and Knight of the Order of Vasa
Order of Vasa
The Royal Order of Vasa was a Swedish Royal order of chivalry, awarded to citizens of Sweden for service to state and society especially in the fields of agriculture, mining and commerce. It was instituted on 29 May 1772 by King Gustav III of Sweden...
. The lungfish Jarvikia and the osteolepiform Jarvikina are named after him.
Books
- Théories de l'évolution des vertébrés reconsidérées à la lumière des récentes découvertes sur les vertébrés inférieurs. Masson, Paris. 1960.
- Basic Structure and Evolution of Vertebrates, 2 Vols. Academic Press, London. 1980
External links
- An Obituary to Erik Jarvik
- "Erik Jarvik (1907-98) : Palaeontologist renowned for his work on the 'four-legged fish'", obituary by Philippe JanvierPhilippe JanvierPhilippe Janvier is a French paleontologist, specialising in Palaeozoic vertebrates, who currently works at the Museum National de l’Histoire Naturelle in Paris. He has written several books and scientific papers on Palaeozoic vertebrates and contributed to the Tree of Life phylogeny project...
.