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Standard Snake Evolution Story Stymied by Spate of Fossil Discoveries

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Standard Snake Evolution Story Stymied by Spate of Fossil Discoveries JOURNAL OF CREATION 29(3) 2015 || PERSPECTIVES Reuters published artistic renditions Standard snake of three of the species, picked up by media outlets globally.3 Diablophis evolution story gilmorei was pictured with dimin­ stymied by utive hind legs and forelegs and Portugalophis lignites as a colourful spate of fossil tree climber with the suggestion of tiny forefeet. discoveries Unknown to most readers of the popular new reports was that these Philip Bell limbs and feet were sheer artistic licence. No trace of limbs or feet was reported by Caldwell et al., neither was ntil early 2015, the ‘earliest’ date there any trace of pectoral or pelvic reported for a fossil snake was U girdles! The systematic description less than 100 Ma old. In January, a of skeletal and dental specimens team led by University of Alberta for Diablophis gilmorei included (Canada) paleontologist Professor Michael Caldwell described fossils of little of the backbone itself—just 4 four new species, in Nature Communi- some precloacal vertebrae and “one 5 cations, which they claimed extended possible sacral vertebra”. Similarly, the snake fossil record backwards by Portugalis lignites was reconstructed about 70 Ma to the Middle Jurassic.1 solely from fragmentary jaw remains. In fact, the fossil material of all four species was acknowledged to be so ‘Earliest’ snake fossils incomplete6 that “we cannot ascertain the shape, length, form and so on of The new species reported were: any aspect of the body of the earliest • Parviraptor estesi (from Dorset, England)—145–140 Ma snakes (~167 Myr ago) reported • Diablophis gilmorei (from Colo­ herein [emphasis added]”. This did rado, USA)—155 Ma not prevent the researchers speculating • Portugalophis lignites (from Gui­ that “all four may have had some form 2 marota, Portugal)—157–152 Ma of reduced forelimbs and hind limbs”. • Eophis underwoodi (from Oxford­ shire, England)—167 Ma. New insights and a new story? The skull anatomy of all four of these ‘ancient’ snakes, they say, is There have long been two com­ similar to that of both modern snakes peting ideas for the origins of snakes. and other fossil snakes. Of course, Some researchers have held that this is unexpected. However, the skull snakes are descended from monitor structure of previously reported fossil lizards which, in turn, descended snakes, Pachyrhachis problematicus from mosasaurs (an aquatic origin). and Haasiophis terrasanctus, also The other view (a terrestrial origin), surprised evolutionary researchers, has gained ascendancy, with land resembling that of modern boas and lizards being deemed the snake pythons (deemed ‘advanced’). Fur­ ancestors.7 Commenting on these thermore, the latter two species were oldest fossil snakes, the writer for preserved with actual fossilized hind Reuters exclaimed: “The remarkable limbs (considered a ‘primitive’ condi­ fossils ... rewrite the history of snake tion).2 It was anticipated that fossils of evolution.” 3 Caldwell et al. were more earlier snakes would turn out to have cautious but did claim that the new more pronounced hind legs as well as fossils “provide insights on snake front legs. So what of the four species evolution”.1 reported by Caldwell’s team? 8 PERSPECTIVES || JOURNAL OF CREATION 29(3) 2015 with Michael Caldwell (author of the earlier 2015 paper1) even suggesting it may belong to an extinct amphibian group.14 Nevertheless, the media proclaimed it a four­legged snake. Evolutionary developmental biologist Prof. Martin Cohn claimed: “this could be one of the most important fossils ever found. The combination of snake­ like body with complete forelimbs and hindlimbs is like a snake version of Archaeopteryx.”15 Even accepting it as a true snake, Tetrapodophis is somewhat pro­ blematic for the conventional evolu­ tionary view. Yes, it partially narrows the approx. 40 Ma ‘time gap’ mentioned earlier. However, Figure 1. Tetrapodophis amplectus—literally ‘four footed snake’ with an ‘embrace’ Tetrapodophis is certainly not morph­ ologically transitional between those In fact, the dates assigned to the occurred (the loss, then regaining of ‘earliest’ (limbless) snakes and the new fossils posed something of a dil­ limbs over millions of years violating later snake fossils with hind limbs; emma, as Caldwell acknowledged: Dollo’s Law 12), so although these namely Pachyrhachis problematicus, “Importantly, there is now a significant early snakes appear to have been Haasiophis terrasanctus and knowledge gap to be bridged by future limbless (based on the fossils alone) Eupodophis descouensi—notwith­ research, as no fossils [sic] snakes are it is presumed that they possessed legs, standing that evolutionists will have known from between 140 to 100 front and back. During the 70 Ma of to claim that the ‘earliest’ fossil 8 Ma ago” (but see later). If mature, time between Eophis underwoodi snakes also had four limbs—and biologically diverse snakes (with and the younger hind­limbed snakes, larger ones at that. Speaking of the ‘advanced’ crania) already existed by snakes were envisaged to have been limbs of Tetrapodophis, one of the 167 Ma ago (the ‘age’ of the oldest diversifying geographically and authors of the Science paper, Dr fossil), evolutionary paleontologists biologically, principally by virtue of Nick Longrich (University of Bath, now had little option but to argue for elongation of the body and reduction UK), says they were “far from being an even earlier origin for snakes. One in size of the legs. ‘vestigial’ evolutionary leftovers, of Caldwell’s colleagues, Sebastián dangling uselessly”.16 Instead, it is Apesteguía (from the National Sci­ believed that Tetrapodophis used First four-legged snake entific and Technical Research Coun­ its long, clawed fingers and toes for cil, Argentina), believes snakes must In July, a further species of fossil 3 grasping onto its prey, conveyed by have first appeared about 190 Ma ago. 13 snake was reported in Science: the species name amplectus, meaning The evolutionary story was further • Tetrapodophis amplectus (from ‘embrace’. This was portrayed in stymied by the lack of hard evidence Brazil)—113 Ma. artistic reconstructions of the creature. for limbs or limb girdles.9 A complete skeleton of the ani­ Even the preserved remains of its last Caldwell’s team advanced the mal is preserved (figure 1), in contrast meal were fossilized, some sort of ‘revolutionary’ view that the snakes to the much more fragmentary fossil small vertebrate. evolved their characteristic skull morphology long before losing their remains of the four ‘older’ species. 10 The creature possessed 160 spinal legs. They had little choice in taking The five ‘ancient’ snake and 112 tail vertebrae and beautifully this step for two reasons: (1) the species reassessed modern­looking skulls of all four of preserved hind limbs and forelimbs. these ‘oldest’ snakes; (2) the fact that Ironically, this exquisite fossil has However the debate on this fas­ much ‘younger’ snakes (such as the created a quandary for researchers in cinating little creature pans out, the 94­Ma­old Eupodophis 11) had small this field—confusion rather than clarity. fact remains that, from an evolution­ hind limbs. It wouldn’t do to argue Some are even cautious about whether ary perspective, the fossils fail to fur­ for an evolutionary reversal having Teptrapodophis is actually a true snake, nish the evidence for their story. The 9 JOURNAL OF CREATION 29(3) 2015 || PERSPECTIVES ‘earliest’ snake fossils appear mature, 4. The cloaca is the shared opening for the expulsion of faecal matter and urine, also used ‘advanced’, and limbless. 54 Ma after during copulation. Precloacal vertebrae are their first appearance inEophis under- those back bones which are close to, but in front of, the cloaca. woodi, Tetrapodophis amplectus turns 5. See ref. 1. The sacral part of the backbone is the up with four fully functional legs and region where a pelvic girdle would be supported feet! It is now imperative that evo­ if there was one. lutionary paleontologists find much 6. The photographs and illustrations appearing in the paper’s illustrations are restricted to ‘older’ fossil snakes (about 190 Ma) details of skull and jaw elements (plus teeth) showing much more developed hind and comparisons of vertebral bones. One can be sure that any pelvic or limb elements would legs and forelegs (and associated pel­ have taken pride of place, had they been found. vic and pectoral girdles respective­ 7. Bell, P., Of snakes, lizards and mosasaurs— ly) than observed in Tetrapodophis evolutionists puzzle over snake origins, Creation 31(3):15–17, 2009; creation.com/snakes. amplectus. In addition, such creatures 8. University of Alberta, The world’s oldest known should show much less body elonga­ snake fossils: rolling back the clock by nearly 70 tion than in ‘later’ snakes. million years, www.sciencedaily.com, January, 2015; accessed 5 February 2015. 9. The best they could offer was “one potential sacral vertebra in Parviraptor estesi” (in Creation affirmed contrast to most other snakes) and “another in the vertebral specimens referred to Diablophis Evolutionary paleontologists will gilmorei ...”. That these were robust led them to speculate about “the possible presence of robust continue to seek fossils which def­ pelvic girdles and hind limbs”. initively answer the conundrum 10. This is the opposite of the conclusion of a of snake origins. The snake fossil recent paper on the fossil snake Coniophis precedens; Longrich, N.R., Bhullar, B.–A.S. record still says no to evolution! and Gauthier, J.A., A transitional snake from From a creationist perspective, the the Late Cretaceous period of North America, Nature 488:205­208, 2012. four oldest fossils are likely the 11. Sarfati, J., Another leggy snake? What should remains of the types of snakes we creationists think? 29 April 2008; creation.com/ would readily recognize in today’s another­leggy­snake. world. Tetrapodophis is part of the 12. Dollo’s Law is named after Belgian biologist Louis Dollo.
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