Friday, March 30, 2007

Re: How far back can the lungfish be traced? Does it predate its evolutionary descendants?


As per my usual policy, I am responding to your private message on a creation, evolution or design topic,

[Left: Fossil may be earliest arm bone, BBC]

publicly via my blog, CED, minus your personal identifying information.

----- Original Message -----
From: AN
To: Jones Stephen E.
Sent: Friday, March 30, 2007 6:35 AM
Subject: lungfish

hope all is well

Thanks. I am very well, having yesterday reached my target weight of 70.0 kgs (154 lbs), a loss of nearly 17 kgs (~37 lbs) (or ~19% of my body weight) from the 86.8 kg (191 lbs) I was ~10 months ago!

>How far back can the lungfish be traced? do you know?

According to paleontologist Robert L. Carroll (1988) "the earliest-known lungfish, Diabolichthyes" is "from the Lower Devonian [~416-397.5 mya] of China":

"In contrast with all later genera, the earliest-known lungfish, Diabolichthyes from the Lower Devonian of China, shows a remarkable mosaic of characters considered typical of lungfish and primitive rhipidistians .... The pattern of the skull roof is clearly comparable with that of later lungfish, but the ventral surface of the skull shows that the basicranial articulation was still mobile and that the palatoquadrate was not fused to the braincase. The posterior portion of the braincase has not been described, but comparison with the primitive rhipidistian Youngolepis suggests that the ethmoid and otic-occipital elements were separately ossified. The premaxilla is recognizable as a distinct tooth-bearing bone of the skull margin that separates the anterior narial opening from the mouth cavity. The vomer occupies a position that is comparable to that of primitive rhipidistians, and the parasphenoid is a long, toothed element extending anteriorly between the pterygoids. In contrast with all later lungfish, the dentary retains marginal teeth. On the other hand, the teeth on the premaxilla do not form a marginal row but were exposed primarily within the mouth cavity. The teeth covering the pterygoid and prearticular are densely packed and arranged in a radiating pattern, as in later lungfish, but are not fused to form definite tooth plates. Diabolichthys is clearly allied with later lungfish in the emphasis on the palatal dentition and in the pattern of the dermal skull roof, but it retains many features that reflect an ancestry among the crossopterygians. The postcranial skeleton of Diabolichthys has not been described, but that of the slightly younger genus Uranolophus resembles that of rhipidistians ... Diabolichthys comes from a facies that is transitional between marine and continental. Other early Devonian lungfish are known from freshwater and marine deposits. All lungfish other than Diabolichthys are distinguished by ossification of the braincase as a single unit to which the palatoquadrate is fused, the loss of the pre maxillae, and the great reduction in the anterior extent of the parasphenoid. The advanced pattern of the palate and braincase are already evident in Uranolophus from the Lower Devonian of North America .... Unlike most later lungfish, Uranolophus lacks tooth plates. The pteryogoids are elongate triangular bones that cover most of the palate. Both they and the prearticulars bear tooth ridges on their margins. Well-defined tooth plates are a hallmark of more advanced lungfish. In the middle Devonian genus Dipterus ... there are large paired plates with radiating rows of denticles that occupy much of the surface of the pterygoids and smaller plates that developed from the vomers. Another pair are borne on the prearticulars." (Carroll, R.L., "Vertebrate Paleontology and Evolution," W.H. Freeman & Co: New York NY, 1988, p.148)

Although this reference is ~20 years ago, it still seems to be the case that, "The oldest fossil dipnoan [lungfish] is Diabolichthyes, from the Lower Devonian of Yunnan, China":

"Fossilized lungfish burrows of Gnathorhiza have been found in rocks as old as the Permian, with the lungfish still inside, and older (empty) burrows are known from the Carboniferous and Devonian. The oldest fossil dipnoan is Diabolichthyes, from the Lower Devonian of Yunnan, China. It is not clear whether this particular fish was marine or lived in freshwater like modern lungfish, but both marine and freshwater fossils of other groups are known. " ("Introduction to the Dipnoi: the lungfish," University of California Museum of Paleontology, Berkeley, 30 November 2004).

There are more early lungfish fossils belonging to the genus Dipterus (of which Diabolichthyes was not a member):

"Dipterus ... genus of very primitive lungfish, among the earliest known, found as fossils in European and North American Devonian rocks (the Devonian Period lasted from 408 to 360 million years ago). Very similar to the crossopterygians, the lobe-finned fishes that gave rise to the first amphibians, Dipterus retained many archaic features, including two dorsal fins and a tail that resembled a lobe-finned tail. Functional lungs were probably present in Dipterus, and a freshwater habitat is indicated. The skull bones of Dipterus, though still primitive, consist of a mosaic of small bones; Dipterus had already initiated the unusual bone pattern seen in more advanced lungfish. Similarly, Dipterus evidences the beginnings of the lungfish trend toward extreme deossification of skeletal elements. Dipterus was probably the direct ancestor of the modern Australian lungfish, the genus Neoceratodus." ( "Dipterus," Encyclopaedia Britannica Online 2007. Accessed 30 March 2007. Emphasis original. )

which were "of middle Devonian age" (~397.5-385.3 mya):

"Early lungfishes are represented by the genus Dipterus ... Dipterus, a fish of middle Devonian age, possessed many of the generalized sarcopterygian characters that were outlined above for the primitive air-breathing fishes, such as a long, fusiform body terminating in a strong, heterocercal tall, paired fins of the archipterygial type, with a strong central axis down the middle of each fin, and with subsidiary bony rays diverging on either side of this axis, and two dorsal fins. The large, heavy rounded scales were of the cosmoid type. Contrasted with these primitive characters there were various specialized features that indicate even in as early a form as Dipterus the trends that were to take place in the evolution of the dipnoans. For instance, there was considerable reduction of bone in the internal skeleton of this fish, and such a development is found in all of the later lungfishes. The braincase, too, was poorly ossified, although in those Devonian lungfishes in which the braincase has been preserved a certain amount of bone is present. Subsequent to Devonian times the ossification of the braincase was to be completely suppressed. The jaws were partially ossified, yet even here a process of chondrification was beginning that was to become typical of later dipnoans. The skull was composed of numerous bony plates. In general there was a great multiplication of bones covering the head in Dipterus, and because of this it is almost impossible to indicate any homologies between the bones of the skull in this fish and the skull bones in other bony fishes. Likewise, the dentition in Dipterus had become highly specialized. The marginal teeth were suppressed in both the upper and lower jaws, and mastication of the food was effected by large, tooth-bearing plates, those above being formed by the pterygoid bones of the palate and those below by the prearticular bones of the lower jaw. On these plates the teeth were arranged in a fan-shaped fashion, a pattern that was to be carried on through the evolutionary history of the lungfishes. Obviously such teeth were adapted for crushing hard food, and it is probable that the food of the Devonian lungfish, Dipterus, was rather similar to that of the modern Australian lungfish, consisting of small invertebrates and vegetable matter." (Colbert, E.H. & Morales, M., "Evolution of the Vertebrates: A History of the Backboned Animals Through Time," [1955], John Wiley & Sons: New York NY, Fourth Edition, 1990, Second Printing, 1992, p.63)

>i can not find on web.

Agreed that dates for the earliest lungfish fossils are hard to find on the Web. Wikipedia's article Lungfish is a good place to start, with a Taxonomic History that starts with Diabolichthyidae but no separate page on it, nor dates. But it has further external links to: Lungfish information site; Dipnoiformes at and Dipnoi at the University of California Museum of Paleontology.

>does it predate its evolutionary descendants?

First, your question seem to presuppose that "descendants" must necessarily be "evolutionary," and therefore if all land vertebrates (amphibians, reptiles, birds, mammals and ultimately humans) descended from "a single species of freshwater lobe finned fish" then it must necessarily have "evolved":

"Prior to the Devonian period (between 410 and 360 million years ago), nothing lived on land, save for a few spiky, low plants, some scorpions and other insects. The earth was congregated into large continents completely different from the ones we know today, and in a constant - albeit slow - state of change. There were massive freshwater lakes, and while the land was a bare, desolate place, these lakes and oceans writhed with life. ... It was during this period, often called the Age of Fishes, that the first bony fishes, the vertebrates, appeared on the scene. ... The vertebrates were divided into two groups: the ray-finned fishes, or Actinopterygii, with the single dorsal fin and paired pectoral and pelvic fins common to most modern fishes; and the lobe-finned fishes - the coelacanth, the lungfish, and the rhipidistian-whose fins appeared to sprout from the end of fleshy, limb-like lobes, almost like toeless legs. These were known as Sarcopterygii (from the Greek sarco meaning fleshy, and pterygii, wing or fin), and were characterised also by their extra dorsal fin. ... Some time towards the end of the Devonian period, a single species of freshwater lobe finned fish evolved legs. In its new guise of Ichthyostega (literally, walking fish) it crawled out of the water to conquer the land this much scientists agreed upon. What was not so certain was which of the group evolved into Ichthyostega: the lungfish, rhipidistian, or coelacanth?" (Weinberg, S., "A Fish Caught in Time: The Search for the Coelacanth," [1999], Fourth Estate: London, Reprint, 2000, pp.28,30)

in "the standard scientific theory" sense that "God had no part in this process" (my emphasis):

"In one of the most existentially penetrating statements ever made by a scientist, Richard Dawkins concluded that `the universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind, pitiless indifference.' Facing such a reality, perhaps we should not be surprised at the results of a 2001 Gallup poll confirming that 45 percent of Americans believe `God created human beings pretty much in their present form at one time within the last 10,000 years or so'; 37 percent prefer a blended belief that `human beings have developed over millions of years from less advanced forms of life, but God guided this process'; and a paltry 12 percent accept the standard scientific theory that `human beings have developed over millions of years from less advanced forms of life, but God had no part in this process.'" (Shermer, M.B., "The Gradual Illumination of the Mind," Scientific American, February 2002. My emphasis)

If so then you would have bought into Darwin's (and Darwinists') straw man and false dilemma fallacies that I blogged about the other day that "creation" necessarily must be what Darwin in his Origin of Species called "the ordinary view of each species having been independently created."

And therefore if "species ... had descended, like varieties, from other species":

"In considering the Origin of Species, it is quite conceivable that a naturalist, reflecting on the mutual affinities of organic beings, on their embryological relations, their geographical distribution, geological succession, and other such facts, might come to the conclusion that species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species inhabiting this world have been modified, so as to acquire that perfection of structure and coadaptation which justly excites our admiration." (Darwin, C.R., "The Origin of Species By Means of Natural Selection," John Murray: London, Sixth Edition, 1872, Reprinted, 1882, p.2)

then (according to Darwin, Darwinists - and you??) they "had not been ... created" at all!

Second, according to Colbert & Morales, evolutionists don't claim that the "evolutionary descendants" of lungfish were anything other than lungfish, i.e. "the lungfishes ... are not and never have been on the direct line of evolution leading from fishes to the first land-living vertebrates" because they ""show too many specializations, even in the earliest known stages of their evolutionary history":

"The ability of the lungfishes to breathe air is certainly suggestive of an intermediate stage between fishes and land-living vertebrates. (In this connection it is interesting to note that the Australian lungfish is able to `walk' along the bottom of the rivers or pools in which it lives by using its paired fins like legs.) Yet in spite of such specializations in the lungfishes directed toward a method of surviving out of the water, the total evidence points quite clearly to the fact that these vertebrates are not and never have been on the direct line of evolution leading from fishes to the first land-living vertebrates. Briefly the lungfishes show too many specializations, even in the earliest known stages of their evolutionary history, for vertebrates that might occupy an intermediate position along the line from fishes to amphibians." (Colbert & Morales, Ibid., pp.62-63).

Third, if your question is "does it, the earliest fossil lungfish, predate" the earliest tetrapods, then the answer appears to be no, because the earliest fossil tetrapod humerus dates from the Late Devonian (~385.3-359.2 mya):

"The Early Evolution of the Tetrapod Humerus," Shubin, N.H., et al., Science, Vol. 304, 2 April 2004, pp.90-93 A tetrapod humerus from the Late Devonian of Pennsylvania has a novel mix of primitive and derived characters. A comparative analysis of this fossil and other relevant humeri from the Devonian shows that the role of the limb in propping the body arose first in fish fins, not tetrapod limbs. The functional diversity of the earliest known limbs includes several different kinds of appendage design. This functional diversity was achieved with a humeral architecture that was remarkably conserved during the Devonian. ...

(although it was controversial-see BBC "Fossil may be earliest arm bone" above) or even "about 10 million years" earlier in "the late Frasnian [~385.3-374.5 mya] (mid-Late Devonian)":

"Comment on `The Early Evolution of the Tetrapod Humerus'," Ahlberg, P.E., Science, 17 September 2004 ... In their analysis of humeral evolution in early tetrapods (taken here as meaning vertebrates with limbs), Shubin et al. (1) described a suite of derived characters that represents a significant advance on previous analyses (2-4). This makes their negative assessment of GSM 104536, the humerus provisionally attributed to Elginerpeton pancheni (2, 4, 6), all the more surprising. The specimen (see Fig. 1, A to F) derives from the late Frasnian (mid-Late Devonian) locality of Scat Craig in Scotland, and is thus about 10 million years older than the Catskill Formation humerus ANSP 21350 that forms the centerpiece of the Shubin et al. study (1, 7). ...

So the fossil evidence is consistent with the common ancestry of lungfish and tetrapods (and therefore of all land vertebrates: amphibians, reptiles, birds mammals including humans with fish), as the Young-Earth Creationist Kurt Wise admitted, in that they "are fossils that stand intermediate between the group from which they are descendent and the one to which they are ancestral-both in stratigraphic position and in morphology", including "Ichthyostega among the amphibians":

"Another class of fossil evidence comes in individual stratomorphic intermediates. These are fossils that stand intermediate between the group from which they are descendent and the one to which they are ancestral-both in stratigraphic position and in morphology. They have a structure that stands between the structure of their ancestors and that of their descendants. However, they are also found in the fossil record as younger than the oldest fossils of the ancestral group and older than the oldest fossils of the descendent group. ... And examples of stratomorphic intermediates do exist. Mammal-like reptiles stand between reptiles and mammals, both in the position of their fossils and in the structure of their bones. The same can be said of the anthracosaurs, which stand between amphibians and reptiles, and the phenacodontids, which stand between the horses and their claimed ancestors. In like manner, some fossil genera are stratomorphic intermediates in the group in which they are classified. They are the oldest fossils known in the group and most similar to the group from which they are supposedly descendent. Examples include Pikaia, among the chordates, Archaeopteryx among the birds, Baragwanathia among Lycopods, Ichthyostega among the amphibians, Purgatorius among the primates, Pakicetus among the whales and Proconsul among the hominoids." (Wise, K.P., "The Origin of Life's Major Groups," in Moreland, J.P., ed., "The Creation Hypothesis: Scientific Evidence for an Intelligent Designer," InterVarsity Press: Downers Grove IL, 1994, pp.226-227)

But common ancestry is not necessarily evolution, since, as Christian philosopher Del Ratzsch has pointed out, God could intervene supernaturally in chains of ancestral descent, and "leave unchallenged ... that all species derive ultimately from some common ancestor":

"Suppose contemporary evolutionary theory had blind chance built into it so firmly that there was simply no way of reconciling it with any sort of divine guidance. It would still be perfectly possible for theists to reject that theory of evolution and accept instead a theory according to which natural processes and laws drove most of evolution, but God on occasion abridged those laws and inserted some crucial mutation into the course of events. Even were God to intervene directly to suspend natural law and inject essential new genetic material at various points in order to facilitate the emergence of new traits and, eventually, new species, that miraculous and deliberate divine intervention would by itself leave unchallenged such key theses of evolutionary theory as that all species derive ultimately from some common ancestor. Descent with genetic intervention is still descent-it is just descent with nonnatural elements in the process." (Ratzsch, D.L., "The Battle of Beginnings: Why Neither Side is Winning the Creation-Evolution Debate," InterVarsity Press: Downers Grove IL, 1996, pp.187-188).

Which then would not be evolution at all":

"Darwin ... wrote in a letter to Sir Charles Lyell, the leading geologist of his day: `If I were convinced that I required such additions to the theory of natural selection, I would reject it as rubbish...I would give nothing for the theory of Natural selection, if it requires miraculous additions at any one stage of descent.' [Darwin, C.R., Letter to C. Lyell, October 11, 1859, in Darwin, F., ed., "The Life and Letters of Charles Darwin," [1898], Basic Books: New York NY, Vol. II., 1959, reprint, pp.6-7]. This is no petty matter. In Darwin's view, the whole point of the theory of evolution by natural selection was that it provided a non-miraculous account of the existence of complex adaptations. For what it is worth, it is also the whole point of this book. For Darwin, any evolution that had to be helped over the jumps by God was not evolution at all." (Dawkins, R., "The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design," W.W Norton & Co: New York NY, 1986, pp.248-249. Emphasis original)

but rather "divine creation", i.e. "God ... influencing key moments in evolutionary [sic] history" (my emphasis):

"At first sight there is an important distinction to be made between what might be called 'instantaneous creation' and 'guided evolution'. Modern theologians of any sophistication have given up believing in instantaneous creation. ... many theologians ... smuggle God in by the back door: they allow him some sort of supervisory role over the course that evolution has taken, either influencing key moments in evolutionary history (especially, of course, human evolutionary history), or even meddling more comprehensively in the day-to-day events that add up to evolutionary change. ... In short, divine creation, whether instantaneous or in the form of guided evolution, joins the list of other theories we have considered in this chapter." (Dawkins, Ibid., pp.316-317)


Thanks. And the same to you.

Stephen E. Jones, BSc. (Biology).

Exodus 10:21-29. 21Then the LORD said to Moses, "Stretch out your hand toward the sky so that darkness will spread over Egypt-darkness that can be felt." 22So Moses stretched out his hand toward the sky, and total darkness covered all Egypt for three days. 23No one could see anyone else or leave his place for three days. Yet all the Israelites had light in the places where they lived. 24Then Pharaoh summoned Moses and said, "Go, worship the LORD. Even your women and children may go with you; only leave your flocks and herds behind." 25But Moses said, "You must allow us to have sacrifices and burnt offerings to present to the LORD our God. 26Our livestock too must go with us; not a hoof is to be left behind. We have to use some of them in worshiping the LORD our God, and until we get there we will not know what we are to use to worship the LORD." 27But the LORD hardened Pharaoh's heart, and he was not willing to let them go. 28Pharaoh said to Moses, "Get out of my sight! Make sure you do not appear before me again! The day you see my face you will die." 29"Just as you say," Moses replied, "I will never appear before you again."

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