Creationism in Crisis - Oldest Known Bat Fossil Give Clue to Evolution of Flying Mammals

Creationism in Crisis

Oldest Known Bat Fossil Give Clue to Evolution of Flying Mammals

Photo of a newly described bat skeleton representing Icaronycteris gunnelli. This specimen is the holotype, the name-bearing representative of a new species, and is in the American Museum of Natural History’s research collections.

Mick Ellison/© AMNH

Fig 3. Skeleton of paratype of Icaronycteris gunnelli
(ROM:Palaeobiology-Vertebrate Fossils:52666).

Rietbergen TB, van den Hoek Ostende LW, Aase A, et al. (2023)

Oldest Bat Skeletons Ever Found From Wyoming Fossils | AMNH

The evolution of bats is far from clear because of the paucity of fossils. It is interesting therefore that the oldest known fossilised bat has been discovered in Wyoming, USA, in the Green River Formation. This adds just another chapter to the account of how the Green River Formation refutes creationism, as I'll go into shortly.


First, a bit about the evolution of bats from ChatGPT:

Bats are a unique group of mammals that have adapted to a life of flight. The evolution of bats is a subject of much debate among scientists, but recent studies suggest that they likely evolved from small, arboreal, insect-eating mammals around 50 million years ago. Fossil evidence from the Eocene period supports this theory, showing that early bats had elongated fingers with membranes stretched between them, much like modern bats.

One of the most significant challenges in studying the evolution of bats is understanding how flight evolved. Recent studies have shed light on this question, suggesting that flight evolved in bats through a process known as "penny-plane" aerodynamics, where the wings generate lift by creating a vortex of air. This mechanism is unique to bats and is not found in any other flying animals.

Another interesting aspect of bat evolution is their remarkable ability to echolocate, or use sound waves to navigate and locate prey. This ability likely evolved early in bat evolution, and recent studies suggest that it may have co-evolved with the development of flight.

Overall, the evolution of bats is a fascinating topic that continues to be the subject of much research and debate. By studying the fossil record and the behavior of modern bats, scientists are gaining new insights into the origins and adaptations of these unique mammals.

Reference:

Simmons, N. B., & Seymour, K. L. (2021). Evolution of bats. In Mammalogy (pp. 294-317). Springer, Cham.

ChatGPT. (2023, April 14). Tell me about the evolution of bats, with references, please. [Response to a question]. Retrieved from https://github.com/openai/gpt-3

Before moving on to the new fossil, I'll deal briefly with the Green River Formation, because it utterly refutes another creationist article of faith - the alleged Global flood a few thousand years ago.

Green River Exposes Layers of Creationist Lies

Here is what ChatGPT found:

The Green River Formation is a geological formation located in the western United States, primarily in the states of Wyoming, Utah, and Colorado. It is famous for its extensive deposits of fine-grained sedimentary rocks that date back to the Eocene epoch, approximately 50 million years ago.

The Green River Formation contains a rich fossil record of plants and animals that lived in and around ancient lakes and wetlands. These fossils provide valuable insights into the evolution of life on Earth during the Eocene, as well as the paleoclimate and paleoenvironment of the region.

The presence of the Green River Formation and its fossils presents a challenge to the Biblical Flood story, which holds that a catastrophic flood covered the entire Earth and deposited the vast majority of sedimentary rocks that we see today. The Green River deposits, however, show no evidence of being formed by a single, catastrophic event.

Instead, the Green River Formation is consistent with a gradual accumulation of sediment over a long period of time, likely hundreds of thousands to millions of years. The fine-grained nature of the sediment suggests deposition in a quiet, low-energy environment, such as a lake or wetland, rather than a high-energy flood event.

Furthermore, the fossils found in the Green River Formation are indicative of a subtropical climate and ecosystem, not the harsh conditions that would be expected in the aftermath of a global flood. For these reasons, the Green River deposits are considered strong evidence against the occurrence of a Biblical Flood as a global, catastrophic event.

References:

1. Vail, P.R., and J.L. Perez, 2018. The Green River Formation: A large, long-lived ancient lake system. In The Geology of the Green River Formation, Western USA, edited by L.R. High, J.A. Campbell, and J.W. Gardner, pp. 1-12. Geological Society of America Special Paper 540.
   https://doi.org/10.1130/2018.2540(01)
2. Wilford, J.N., 2005. Fossil layers pose a challenge to flood geology. New York Times.
   https://www.nytimes.com/2005/02/15/science/fossil-layers-pose-a-challenge-to-flood-geology.html
3. National Park Service, n.d. Fossil Butte National Monument - Green River Formation.
   https://www.nps.gov/fobu/learn/nature/green-river-formation.htm
4. Oard, M.J., 2014. The Green River Formation and the true thickness of the rock record. Answers Research Journal 7: 47-53.
   https://answersingenesis.org/geology/rock-layers/green-river-formation-true-thickness-rock-record/

ChatGPT. (2023, April 14) Tell me about the Green River deposits and how they refute the Biblical Flood story [Response to a question].
Retrieved from https://github.com/openai/gpt-3

As though that's not bad enough for creationism, here is what the scientists have to say about the newly identified bat fossil. The new species is described in a paper in the online, open access journal, PLOS ONE by a team led by researchers at the American Museum of Natural History and Naturalis Biodiversity Center in the Netherlands.

From the America Museum of Natural History news release:

Scientists have described a new species of bat based on the oldest bat skeletons ever recovered. The study on the extinct bat, which lived in Wyoming about 52 million years ago, supports the idea that bats diversified rapidly on multiple continents during this time. Led by researchers at the American Museum of Natural History and Naturalis Biodiversity Center in the Netherlands, the study is published today in the journal PLOS ONE.

There are more than 1,460 living species of bats found in nearly every part of the world, with the exception of the polar regions and a few remote islands. In the Green River Formation of Wyoming—a remarkable fossil deposit from the early Eocene—scientists have uncovered over 30 bat fossils in the last 60 years, but until now they were all thought to represent the same two species.

Eocene bats have been known from the Green River Formation since the 1960s. But interestingly, most specimens that have come out of that formation were identified as representing a single species, Icaronycteris index, up until about 20 years ago, when a second bat species belonging to another genus was discovered. I always suspected that there must be even more species there.

This is a step forward in understanding what happened in terms of evolution and diversity back in the early days of bats.

Nancy Simmons, co-author
Curator-in-charge
Department of Mammalogy
American Museum of Natural History

In recent years, scientists from the Naturalis Biodiversity Center started looking closely at Icaronycteris index by collecting measurements and other data from museum specimens.

Paleontologists have collected so many bats that have been identified as Icaronycteris index, and we wondered if there were actually multiple species among these specimens. Then we learned about a new skeleton that diverted our attention.

Tim Rietbergen, first author
Evolutionary biologist
Naturalis Biodiversity Center
The Netherlands

The Fossil Lake deposits of the Green River Formation are simply amazing because the conditions that created the paper-thin limestone layers also preserved nearly everything that settled to the lake’s bottom. One of these bat specimens was found lower in the section than all other bats, making this species older than any of the other bat species recovered from this deposit.

Arvid Aase (not involved in the study)
Park manager and curator
Fossil Butte National Monument, Wyoming, USA

The exceptionally well-preserved skeleton was collected by a private collector in 2017 and purchased by the Museum. When researchers compared the fossil to Rietbergen’s expansive dataset, it clearly stood out as a new species. A second fossil skeleton discovered in the same quarry in 1994 and in the collections of the Royal Ontario Museum was also identified as this new species. The researchers gave these fossils the species name Icaronycteris gunnelli in honor of Gregg Gunnell, a Duke University paleontologist who died in 2017 and made extensive contributions to the understanding of fossil bats and evolution.

Although there are fossil bat teeth from Asia that are slightly older, the two I. gunnelli fossils represent the oldest bat skeletons ever found.

While the I. gunnelli skeletons are the oldest bat fossils from this site, they are not the most primitive, supporting the idea that Green River bats evolved separately from other Eocene bats around the world.

A rapid diversification both geographically and taxonomically, is exactly what we would expect from a major new ability of mammals as the order 'mushroomed' into new niches made available by its ability to fly.

Copyright: © 2023 The authors.
Published by PLoS Open access. (CC0 1.0)

More detail is given in the team's open access paper in PLOS ONE:

Abstract

The Fossil Lake deposits of the Green River Formation of Wyoming, a remarkable early Eocene Lagerstätte (51.98 ±0.35 Ma), have produced nearly 30 bat fossils over the last 50 years. However, diversity has thus far been limited to only two bat species. Here, we describe a new species of Icaronycteris based on two articulated skeletons discovered in the American Fossil Quarry northwest of Kemmerer, Wyoming. The relative stratigraphic position of these fossils indicates that they are the oldest bat skeletons recovered to date anywhere in the world. Phylogenetic analysis of Eocene fossil bats and living taxa places the new species within the family Icaronycteridae as sister to Icaronycteris index, and additionally indicates that the two Green River archaic bat families (Icaronycteridae and Onychonycteridae) form a clade distinct from known Old World lineages of archaic bats. Our analyses found no evidence that Icaronycteris? menui (France) nor I. sigei (India) belong to this clade; accordingly, we therefore remove them from Icaronycteridae. Taken in sum, our results indicate that Green River bats represent a separate chiropteran radiation of basal bats, and provide additional support for the hypothesis of a rapid radiation of bats on multiple continents during the early Eocene.

Rietbergen TB, van den Hoek Ostende LW, Aase A, Jones MF, Medeiros ED, Simmons NB (2023)
The oldest known bat skeletons and their implications for Eocene chiropteran diversification.
PLoS ONE 18(4): e0283505. https://doi.org/10.1371/journal.pone.0283505

Copyright: © 2023 The authors.
Published by PLoS Open access.
Reprinted under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication licence.

Disappointingly for creationists, not only was this early bat fossil found in the dreaded Green River Formation that so comprehensively refutes Bible-literalist creationism, but there is no sign there that the palaeontologists who carried out the study, thought the evidence-free, magical superstition of the creation cult might be a better explanation than the established scientific Theory of Evolution.

I wonder if any creationists are bright enough to work out why that might be.

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