March 19, 2009 | David F. Coppedge

Amazing Fossils: Do They Help Darwin?

Some remarkable fossils have been found recently.  According to the reports, scientists are not sure what to make of them, even though evolutionary language is liberally applied to the interpretation.

  1. Octopus:  The earliest fossil octopus is 100% octopus.  A rare well-preserved octopus fossil, as unlikely as finding a fossilized sneeze according to Live Science, shows all the tentacles, suckers, and even the ink sac.  The specimens, found in Cretaceous rock in Lebanon, push back the evolutionary date for octopus fossils tens of millions of years to 95 million years before the present.  Even though the discoverer said “This provides important evolutionary information,” he was surprised at how similar the fossil is to living species.  “These things are 95 million years old, yet one of the fossils is almost indistinguishable from living species,” said Dirk Fuchs of the Free University in Berlin.  Primitive octopi were presumed to have fleshy fins along their bodies.  “The new fossils are so well preserved that they show, like living octopus, that they didn’t have these structures,” he said.  National Geographic shows a detailed picture of the octopus, tentacles, suckers and all.  An ID website called Intelligent Design and More analyzed the significance of this fossil for evolutionary theory.
  2. Old spider silk:  The oldest sample of spider web silk was found in amber in East Sussex, UK this month.  The BBC News said it’s 140 million years old.  Some pieces of amber from the Cretaceous beds were lying on the surface of a beach.  The article did not mention the evolution of spiders – just that this was the oldest known example of spider silk.  A professor at Oxford said, “If it is confirmed – and we think we have got good evidence for it – then it would be the oldest preserved spider’s web and the oldest fossil silk, I think, in the fossil record.”  It implies the spider spinner already had all the spinneret equipment for mixing the chemicals of this complex material and weaving her web.
  3. Anomalous Anomalocaridid from the Burgess Shale:  Another strange critter from the Cambrian-era Burgess Shale was announced in Science.1  This one, named Hurdia, is similar to the better-known predator Anomalocaris, but had a prominent carapace in front (see National Geographic for artist reconstruction).  Live Science called it a miniature monster.  Its estimated length was one meter.
        Although the paper promised to elaborate on “its significance for early euarthropod evolution,” the E-word never appeared in the body of the paper.  The authors did say that “The phylogenetic analysis we conducted places Hurdia as sister to a group composed of Anomalocaris and Laggania, with these three taxa forming a clade in the stem group of the euarthropods.”  No ancestral progression was therefore shown, unless Anomalocaris was a later species that lost the carapace – but that would represent devolution, not evolution.  The authors said, “If the carapace is homologous with the euarthropod cephalic shield, this head covering may have originated before the last common ancestor of the anomalocaridids and higher euarthropods.”  That is just a speculation.  It doesn’t help evolutionary theory anyway, since it puts the origin of the carapace farther in the past without a transitional form.
  4. Dino-midget:  One of the smallest dinosaurs ever known was found in Canada.  EurekAlert said it is smaller than a housecat and likely ate insects, small mammals and other prey.  “Hesperonychus is currently the smallest dinosaur known from North America,” a member of the discovery team remarked.  “But its discovery just emphasizes how little we actually know, and it raises the possibility that there are even smaller ones out there waiting to be found.”  Nothing was said about how this species evolved.  They inferred from the fused pelvic bones that the creature was fully grown.  Live Science also reported the find.
        Speaking of dinosaurs, EurekAlert also reported a collection of adolescent Sinornithomimus found in Mongolia.  The discoverers presume the individuals died getting stuck in a mud flat.  They inferred that the young represented a herd that perished together.  The skeletons showed exquisite preservation and were oriented in similar directions, suggesting they perished together over a short time.
  5. Fuzzy dinosaur:  Another “feathered dinosaur” from China was announced by Nature News, but its relation to birds seems questionable.  Integumentary filaments were found running along the back of Tianyulong confuciusi; the alleged feathers are only stiff filaments without vanes.  Live Science, nevertheless, emphasized the “feather” interpretation, but the BBC News said the fossil only hints at “fuzzy dinosaurs.”  Whatever the structures were, they were clearly not related to flight.  Were they for display?  for warmth?  Opinions vary.  The authors of the original paper in Nature did not have a clear answer.2  In addition, calling these things feathers would require evolutionary appeals to homology and convergence:

    The unique filaments of Tianyulong add more complexity to the issue of feather origins.  Homology of the structures in Tianyulong and theropods is far from obvious with present data, but cannot be precluded.  Although based on negative evidence, the derived position within the Theropoda for the known appearance of ‘protofeathers’ indicates that earlier theropods lacked integumentary structures, implying in turn that the common ancestor of theropods and ornithischians also lacked such structures and that their appearances in each clade were convergent.

        This fossil represents the first in the Ornithischian branch of dinosaurs to sport integumentary filaments.  The BBC article emphasized the problems this makes for the dinosaur-to-bird scenario.  All the other “feathered dinosaurs” were members of Saurischia, the “lizard-hipped” branch.  One might think that finding “proto-feathers” on a bird-hipped species would excite the believers in dinosaur-to-bird evolution, but Lawrence Witmer (Ohio U) said this “really muddies the waters” of the story.  “The bad news is that something we thought was neatly wrapped up is now not so neat,” he said.  The Ornithischia were all thought to be scaly, like reptiles.  The announced date of this fossil, 150 million years before the present, also puts the filaments long before birds in the evolutionary timeline.  “We now need to rethink what the coat of the ancestral dinosaurs actually was.”  Do the filaments imply warm-bloodedness?  Are they even related to feathers at all?  “We now need to think completely differently about the evidence we already have,” Witmer said.
        Witmer elaborated on the problems in a News and Views commentary in the same issue of Nature.3  The fossil shows three patches of long filaments “reminiscent of the structures thought to be the evolutionary progenitors of feathers,” he said.  “The only problem is that Tianyulong isn’t supposed to have anything like feathers.”  Again, he said, “Tianyulong is not at all closely related to birds and, as a heterodontosaurid ornithischian, is on an entirely separate branch of the dinosaur family tree.”  He doubts that these are feathers at all.  It’s not even clear what part of the skin they emerged from:

    Given the position of Tianyulong near the evolutionary base of ornithischian dinosaurs, the presence of epidermal, filamentous, feather-like structures could mean that the ancestral dinosaur was a fuzzy (though maybe not cuddly) animal.  Of course, that would also mean that a fuzzy coat of protofeathers was lost many times in dinosaur evolution, because lots of dinosaur groups on both great branches of the dinosaur family tree are known to have scaly, reptilian skin (Fig. 1).  But, before complicated scenarios for feather evolution are concocted, the fundamental question to be answered is whether the filaments of Tianyulong are on the outside or inside of the skin’s surface.
        That seemingly simple question is surprisingly hard to answer….

    Even if the filaments are epidermal, and the evidence is ambiguous, it would not prove they were in the lineage of bird feathers.  The evidence from all the claimed feathered dinosaurs at this point “raises the possibility that there may be a range of filamentous epidermal structures in dinosaurs, and that not all such structures may be related evolutionarily to feathers.”  If he is right, there has been a rush to judgment to call these things feathers.  “Perhaps the only clear conclusion that can be drawn from the foregoing is that little Tianyulong has made an already confusing picture of feather origins even fuzzier.

How about a living fossil to cap off this entry?  National Geographic News posted a photo of a young tuatara found near Wellington, New Zealand.  Tuatara are considered a classic “living fossil” because of their “dinosaur-age lineage.”  The dinosaurs are all gone, but this reptile that lived among them survives today, having left no fossils in the 65 million years evolutionists believe separated them.

1.  Daley, Budd, Caron, Edgecombe and Collins, “The Burgess Shale Anomalocaridid Hurdia and Its Significance for Early Euarthropod Evolution,” Science, 20 March 2009: Vol. 323. no. 5921, pp. 1597-1600, DOI: 10.1126/science.1169514.
2.  Zheng, You, Zu and Dong, “An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures,” Nature 458, 333-336 (19 March 2009) | doi:10.1038/nature07856.
3.  Lawrence M. Witmer, “Dinosaurs: Fuzzy origins for feathers,” Nature 458, 293-295 (19 March 2009) | doi:10.1038/458293a.

Sudden appearance, well-adapted creatures, stasis, lack of clear lineal descent – these are not what Charles Darwin would have liked to see.  Fossils represented the biggest problem to his theory in 1859, and despite the bombast of his disciples, continue to throw up obstacles to belief in slow, gradual progression of creatures from simple to complex.

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