David Pearce misleads his audience on coelacanth evolution

David Pearce is a British Christadelphian old earth creationist whose attacks on evolution as shown by his frankly pedestrian Evidence for Design follow the usual argument from personal incredulity, where complexity is deemed too difficult for evolution, a nonsensical claim as any one familiar just with the ability of evolutionary algorithms to effect complex design without direct human involvement shows. Recently, Christadelphian Videos uploaded a video The Awesome Amazing ... World of Fish which took the usual "awe at nature means intelligent designer" approach, one that would completely unimpress biologists specialising in the study of fish whose acceptance of their evolutionary origins in no way diminishes their awe at the splendour of nature. Where Pearce went dreadfully wrong was in his assertion that the coelacanth was a 'living fossil'. What's even more damning is that a 1991 book would have shown him this was wrong.

Pearce immediately blundered when he started his section on the coelacanth (which he incorrectly pronounced "koalacanth" rather than "see-la-canth", strongly suggesting he's never spoken to an actual expert in ichthyology.

With another fish and other fish, which is quite amazing. The koala counts [sic]. This is a living fossil. Here's a picture of a koala counts [sic]. (13:42)

He continues somewhat oddly and I suspect at heart pejoratively by claiming "evolutionists always assumed they became extinct. Something I would say 65 million years ago (14:08)" an assertion which given the lack of evidence and their environment is hardly an unreasonable one to make. After giving a brief overview of the history of their rediscovery, he makes this assertion. From 16:14 he says:

"The experts soon had to agree that this new fish that had been found in the fishing boat was exactly the same fish as the koala cat's fossils, which were supposed to be millions of years old. Here I put them side by side. Top one is the fossil and the bottom one is the living one, which was caught in the fishing boat. So you can see how obviously they are exactly the same fish."

While the fish are clearly related, Pearce is flat-out wrong to say they are exactly the same or that they are a living fossil. Latimeria chalumnae, or the West Indian Ocean coelacanth ranges between 168-200cm with a maximum weight of 95kg. [1]  What about the extinct coelacanths. Let's look at one which definitly does not look identical to L. chalumnae, a mid-Triassic (247-237 million years ago) coelacanth known as Foreyia maxkuhni. From the abstract of the 2017 paper reporting it we read:

A bizarre latimeriid coelacanth fish from the Middle Triassic of Switzerland shows skeletal features deviating from the uniform anatomy of coelacanths. The new form is closely related to a modern-looking coelacanth found in the same locality and differences between both are attributed to heterochronic evolution. Most of the modified osteological structures in the new coelacanth have their developmental origin in the skull/trunk interface region in the embryo. Change in the expression of developmental patterning genes, specifically the Pax1/9 genes, may explain a rapid evolution at the origin of the new coelacanth. This species broadens the morphological disparity range within the lineage of these ‘living fossils’ and exemplifies a case of rapid heterochronic evolution likely trigged by minor changes in gene expression.

An abstract starting off describing the fish as bizarre is definitely communicating that this is no ordinary coeelacanth, as one can see from the illustration from the paper:

 

Figure 1

Skeleton of the new coelacanth Foreyia maxkuhni gen. et sp. nov. (A) Photo and (B) outline of the holotype (PIMUZ A/I 4620). (C) Reconstruction of the whole skeleton.

Note too this fish is much smaller than Latimeria chalumnae as shown by the 10mm scale bar.

In fact, as the evolutionary family tree of coelacanths shown in the paper shows, coelacanth morphology has not remained static: 

Figure 3

Phylogenetic relationships of Foreyia maxkuhni gen. et sp. nov. and developmental origin of the derived characters. (A) Strict consensus trees of the 259 most parsimonious trees of 317 steps (CI = 0.3817, RI = 0.6766) with some of the uniquely derived characters present in Foreyia maxkuhni on the left, and reconstructions of genera with atypical general morphology. (B and C) Shared features of Ticinepomis peyeri and Foreyia maxkuhni (in orange) not included in the cladistics analysis (see main text for numbers). (D) Reconstruction of a coelacanth embryo with localization of embryonic tissues that give rise the derived skeletal features present in Foreyia. It is hypothesized that changes in the expression of Pax9 may have altered the derived characters shown in blue on the reconstruction (E). All the drawings were made by LC. Abbreviation: Boc, basioccipital; Cla, clavicle; Exo, exoccipital; lat. Meso., lateral mesoderm; neur. cr., neural crest; pect. f., pectoral fin; S (numbered), somite. 

One can clearly see evidence of evolutionary change in coelacanths over time; Burgess is simply wrong to argue they are "exactly the same fish". Burgess has clearly not researched this subejct other than blindly copying creationist myths or he would not have made such an unforgiveable mistake.
 

Geologist and former YEC Glenn Morton in a TalkOrigins post of the month makes a similar point about coelacanths not being living fossils

I know the "coelacanth". I know enough about them to know that the coelacanths found in Madagascar are neither the same type of coelacanth fossils that have been found in rocks that are 360 million years old nor the same type of coelacanth found in shallow marine strata that are about 80 million years old. The 360 million year old coelacanths are smaller, lack certain internal structures found in modern coelacanths and belong to a different genera and suborder. The modern coelacanths belong to a different genera than the 80 million year genera. Technically speaking, the modern coelacanth of the genus Latimera has no fossil record. Only the order and suborder that it belongs to has.  

Morton quotes Keith Thomas in Living Fossil: The Story of the Coelacanth which I've acquired to confirm the reference which I reproduce below:

One point has to be emphasized; The living coelacanth is not a living fossil in the very strict sense that members of the species L. chalumnae itself have ever been found as a fossil. In fact, no other species assignable to the genus Latimeria has been found as a fossil either. Latimeria and the Cretaceous fossil genus Macropoma are quite closely related, and we could possibly include them in the same family. Beyond that, all fossil coelacanths belong in the order Coelacanthini (which a minority of zoologists would prefer to call Actinistia, a name for which I can find no use at all). [3] (Emphasis mine)

Enough said. Pearce's comments on the coelacanth are false, and are enough to destroy his credibility as an informed commenter on evolutionary biology. Frankly. my advice is to assume every Christadelphian attacking evolution is woefully uninformed and simply regurgitating long-debunked evangelical apologetic lies.

References

1. https://www.fishbase.org/summary/Latimeria_chalumnae.html
2. Cavin L, Mennecart B, Obrist C, Costeur L, Furrer H. Heterochronic evolution explains novel body shape in a Triassic coelacanth from Switzerland. Sci Rep. 2017 Oct 20;7(1):13695. doi: 10.1038/s41598-017-13796-0. PMID: 29057913; PMCID: PMC5651877.
3. Thomson, Keith Stewart. Living fossil : the story of the coelacanth. United Kingdom: W.W. Norton, 1991, 78