Transitions among amphibians (Talk.Origins)

Response Article

This article (Transitions among amphibians (Talk.Origins)) is a rebuttal regarding a supposed transitional form published by the Talk.Origins Archive under the title Transitional Vertebrate Fossils FAQ.

Response to Transitions among amphibians

CreationWiki response: (Talk.Origins quotes in blue)

Temnospondyls, e.g Pholidogaster (Mississippian, about 330 Ma) -- A group of large labrinthodont amphibians, transitional between the early amphibians (the ichthyostegids, described above) and later amphibians such as rhachitomes and anthracosaurs. Probably also gave rise to modern amphibians (the Lissamphibia) via this chain of six temnospondyl genera , showing progressive modification of the palate, dentition, ear, and pectoral girdle, with steady reduction in body size (Milner, in Benton 1988). Notice, though, that the times are out of order, though they are all from the Pennsylvanian and early Permian. Either some of the "Permian" genera arose earlier, in the Pennsylvanian (quite likely), and/or some of these genera are "cousins", not direct ancestors (also quite likely).

Reference: Palaeos Vertebrates 160.000 Temnospondyli: Overview

This category seems to consist of several kinds of animals, some of which seem to have different varieties. It is claimed that these form a transition from early to later amphibians eventually giving rise to modern amphibians. This claim is based on apparent trends in the palate, teeth, ears, pectoral girdle, and body size. It is interesting that they ignore the time order based on the geologic column referring to them as cousins, rather than ancestors or assuming that genera arose earlier than they have evidence for.

Dendrerpeton acadianum (early Penn.) -- 4-toed hand, ribs straight, etc.

Reference:Palaeos Vertebrates 160.000 Temnospondyli:Overview

Click here for a picture of a fossil skull.

Archegosaurus decheni (early Permian.) -- Intertemporals lost, etc.

While the order is correct there is no reference to any connecting fossils. Not only are Dendrerpeton and Archegosaurus an entire Period apart, but they are significantly different. The only reason for making this link seem to be the assumption of Evolution.

Reference:Palaeos Vertebrates 160.000 Temnospondyli:Overview

Eryops megacephalus (late Penn.) -- Occipital condyle splitting in 2, etc.

Evolutionarily dated as older that Archegosaurus the last type on the list. There is no evidence of any trend in body or head shape.

Reference:Palaeos Vertebrates 160.000 Temnospondyli:Overview

Trematops spp. (late Permian) -- Eardrum like modern amphibians, etc.

Once again there is no evidence of any trend in body or head shape. These types fail to show any evolutionary change.

Click here for picture

Amphibamus lyelli (mid-Penn.) -- Double occipital condyles, ribs very small, etc.

Click here to see picture

Click on the links to see the skeleton.

Paleontology Amphibians, Photovault Image

Paleontology Amphibians, Photovault Image

Amphibamus lyelli

Here are a couple of good ones. Interesting how the last three skull shapes were very different, with no overall trend.

Amphibamus is evolutionarily dated as older than Trematops, Archegosaurus and Eryops; the last three types on the list. There continues to be no evidence of any trend in body or head shape.

Doleserpeton annectens or perhaps Schoenfelderpeton (both early Permian) -- First pedicellate teeth! (a classic trait of modern amphibians) etc.

Doleserpeton

Click here to see picture

The fossils descriptions that I have found are not complete, even if they are combined. Once again there is no evidence of any trend in body or head shape.

---

Schoenfelderpeton

No information available on this type.

---

This a good example of comparing fossil animals without regards for order the animals appear by uniformitarian dating methods and ignoring physical characteristics that show no evidence of any trend.

---

---

From there we jump to the Mesozoic: Triadobatrachus (early Triassic) -- a proto-frog, with a longer trunk and much less specialized hipbone, and a tail still present (but very short).

Triadobatrachus is simply a kind of amphibian with some features similar to those of a frog. While there are similarities in the skulls, they still very different, and the pelvis and hind legs a very different.

Vieraella (early Jurassic) -- first known true frog.

Vieraella is a variety of frog. There are sufficiently large differences with triadobatrachus that claiming a comparison as evidence for evolution is problematic at best. Making a legitimate link between Triadobatrachus and Vieraella would require many intermediate forms, but there are none. Furthermore there is a gap of an entire Period between Triadobatrachus and Vieraella, with no intermediate transitions.

Karaurus (http://www.ebeltz.net/firstfam/geocolum.html early Jurassic]) -- first known salamander.

Click here to see picture

So Karaurus is a variety of salamander. There are no clear links to other types.

---

---

Finally, here's a recently found fossil: Unnamed proto-anthracosaur -- described by Bolt et al., 1988. This animal combines primitive features of palaeostegalians (e.g. temnospondyl-like vertebrae) with new anthracosaur-like features. Anthracosaurs were the group of large amphibians that are thought to have led, eventually, to the reptiles. Found in a new Lower Carboniferous site in Iowa, from about 320 Ma.

Click here to see picture

All that seems to have been found of proto-anthracosaur one is part of the animals pelvis.

---

---

This list consists of totally distinct kinds of animals. Some of the fossil evidence is questionable because of fragmentation. In one case nothing could be found. It shows that they even ignored their own dating methods to come up with a transitional list. They also ignore considerable differences between types in favour of the few similarities that favour evolution.

See Also

• Transitional forms