Friday Fossil Feature – An Over-Whale-Ming Donation!

By Sarah Boessenecker (@tetrameryx)

 

Happy Fossil Friday!

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Mark with his gigantic Basilosaurus vert – kindly donated to the CCNHM! Photo by R. Boessenecker.

Today we’re writing to thank local fossil collector, and founder of the Palmetto Paleontological Society, Mark Bunce.

Mark has a passion for fossils, and started our local fossil club 2 years ago; over the years, Mark has made numerous donations to CCNHM, and many of these fossils are proudly on display. At the most recent meeting, he donated a large Basilosaurus sp. vertebrae – nearly 12 inches in length!

Big vertebrae mean big animals! Photo from Wikipedia.

Big vertebrae mean big animals! Photo from Wikimedia Commons.

Basilosaurus was an early whale – one of the earliest! They lived in the Eocene, and grew to huge sizes. With over 70 vertebrae, Basilosaurs was over 50 feet long – making them a deadly predator of the late Eocene seas.

Basilosaurus still retained hind limbs, though they were highly reduced and not capable of supporting weight on land; it was completely restricted to aquatic environments. Though it wasn’t as highly adapted to ocean life as whales of today, likely spending most of its time near the surface and hunting fish, sharks, and potentially other small whales, it had started to develop the features of modern cetaceans in its ear bones – they were separated from the skull with dense bullae, indicating it could hear directionally underwater.

Museums such as CCNHM are made possible through the donations and help of amateur collectors – over 80% of the material in collections and on display at CCNHM are from amateur collectors, most of them in the Charleston area! In fact, we have so much donated material we are busy working on a display case devoted entirely to amateur collectors and their donations.

Thanks again, Mark, for the wonderful donation!

 

Further Reading:

Bejder, Lars; Hall, Brian K. (2002). “Limbs in whales and limblessness in other vertebrates: mechanisms of evolutionary and developmental transformation and loss”. Evolution and Development 4 (6): 445–458. [Link]

Fahlke, Julia M. (2012). “Bite marks revisited – evidence for middle-to-late Eocene Basilosaurus isis predation on Dorudon atrox (both Cetacea, Basilosauridae)” (PDF). Palaeontologia Electronica 15 (3). Retrieved August 2013. [Link]

Fahlke, Julia M.; Gingerich, Philip D.; Welsh, Robert C.; Wood, Aaron R. (2011). “Cranial asymmetry in Eocene archaeocete whales and the evolution of directional hearing in water”. PNAS 108 (35): 14545–14548. [Link]

Ekdale, E. G. and Racicot, R. A. (2015), Anatomical evidence for low frequency sensitivity in an archaeocete whale: comparison of the inner ear of Zygorhiza kochii with that of crown Mysticeti. Journal of Anatomy, 226: 22–39. doi: 10.1111/joa.12253 [Link]

 

 

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Friday Fossil Feature – whale, whale, whale, it seems all is not lost after all!

By Sarah Boessenecker (@tetrameryx) and Robert Boessenecker (@CoastalPaleo)

 

Happy Fossil Friday!

Today we’re looking at Agorophius pygmaeus, one of the first named odontocetes from North America. Agorophius has a long, complicated history –  and it starts right here, in Charleston!

Our partial braincase of Agorophius pygmaeus.

Our partial braincase of Agorophius pygmaeus. Image by S. Boessenecker.

Agorophius pygmaeus was discovered in the 1840’s at Middleton Place, a plantation in West Ashley. It was found in the Ashley Limestone, and was originally named Zeuglodon pygmaeus, from a partial braincase and single tooth.

A popular tourist site, Middleton Place was the site of discovery of the type specimen. Image Source.

A popular tourist site, Middleton Place was the site of discovery of the type specimen. Image Source.

It was heavily studied throughout the 19th century, but the holotype specimen was lost sometime before 1907 when Frederick True attempted to locate it. However, some 140 years later, Ewan Fordyce re-discovered the tooth of the holotype specimen in the collections of the Harvard Museum of Comparative Zoology in 1980, and was able to match it to the illustrations from the original publication. However, the partial skull has never been found again.

The skull was lost in the early 1900's, but the tooth has since been found, and luckily there's incredibly detailed illustrations for comparison. From Godfrey et. al. 2016.

The skull was lost in the early 1900’s, but the tooth has since been found, and luckily there’s incredibly detailed illustrations for comparison. From Godfrey et al 2016.

This missing holotype has wreaked havoc in odontocete taxonomy; Agorophius exhibited many uniquely transitional features and many authors have discussed the “Agorophiidae;” for a long time, Agorophius was one of the only early odontocetes known. The loss of the holotype caused “taxonomic paralysis” – naming of new genus and species was on hold as new specimens couldn’t be compared to the original, else risk bloat and naming new species when they were actually just new specimens of an already named genus or species.

A new paper recently published by Stephen Godfrey et al. (2016) refers two new skulls to Agorophius pygmaeus, one from the Chandler Bridge Formation (23-24 Ma) and another from the older Ashley Formation (~26-29 Ma); both of these specimens include basicrania and earbones, and are somewhat more complete than the lost holotype.

New specimens described in the new paper. From Godfrey et al 2016.

New specimens described in the new paper. From Godfrey et al 2016.

However, neither specimen has teeth, and the only surviving part of the type specimen is a tooth – this means that the identification is based on the original illustrations; various authors have debated whether or not this is kosher. Ultimately, illustrations of Agorophius are extremely detailed and better than many photographs of fossil cetaceans in papers published in the last few decades, and as such are accepted as a means for identification.

This recent paper is a significant leap forward in the study of early odontocetes; CCNHM also has material that is referable to Agorophius or even Agorophius pygmaeus, and gives CCNHM researchers & affiliates a “green light” toward studying our own Agorophius and dwarf agorophiid specimens.

 

Further Reading:

Stephen J. Godfrey, Mark D. Uhen, Jason E. Osborne and Lucy E. Edwards (2016). A new specimen of Agorophius pygmaeus
(Agorophiidae, Odontoceti, Cetacea) from the early Oligocene Ashley Formation of South Carolina, USA. Journal of
Paleontology, 90, pp 154-169 doi:10.1017/jpa.2016.4   [Link]

Fordyce, R. E., 1981, Systematics of the odontocete whale Agorophius
pygmaeus and the Family Agorophiidae (Mammalia: Cetacea): Journal of
Paleontology, v. 55, no. 5, p. 1028–1045.    [Link]

 

 

 

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Friday Fossil Feature – The head bone’s connected to the… neck bone…

By Sarah Boessenecker (@tetrameryx)

Happy Fossil Friday!

Fossils don’t prepare themselves, and rarely come out of the ground looking the way you seem them on display in a museum. Here at the CCNHM, we are building a team of dedicated, hard-working volunteer preparators to help us clear out our backlog of fossil cetaceans!

How fossils are often found in the field - it takes skill and patience to make sense of this! Photo by S. Boessenecker

How fossils are often found in the field – it takes skill and patience to make sense of this. Photo by S. Boessenecker.

Fossil preparation takes time, skill, patience, and a certain eagerness. Cleaning off a fossil is a rewarding experience – you’re the first to see this bone surface in millions of years!

Dental picks and tooth brushes - good for more than just your teeth! Photo by S. Boessenecker.

Dental picks and tooth brushes – good for more than just your teeth! Photo by S. Boessenecker.

We currently have 2 amazing student volunteers; Jordy Taylor is a masters student in the Biology department, working with fossil sharks, and Brad Thompson is an undergrad in the geology department and museum docent.

Using brushes, dental picks, and some hard work, they’re helping us to expose whale and dolphin skulls from the Oligocene of the Charleston area.

Brad's skull - he's doing a fantastic job! Photo by S. Boessenecker.

Brad’s skull – he’s doing a fantastic job! Photo by S. Boessenecker.

Brad’s fossil is a braincase of a medium sized baleen whale from the upper Oligocene (~28 Ma) Chandler Bridge Formation of Summerville, South Carolina – a baleen whale in the family Eomysticetidae, the earliest toothless baleen whales.

Brad working on his mysticete braincase. Photo by R. Boessenecker.

Brad working on his baleen whale braincase. Photo by R. Boessenecker.

Jordy is working on several waipatiid dolphin skulls – two nearly complete skulls in sandstone blocks, and a third fragmentary skull consisting of fragments of a partial braincase.

Jordy working on her Waipatiid skull. Photo by R. Boessenecker.

Jordy working on her waipatiid skull. Photo by R. Boessenecker.

Our docents take photos and detailed notes to document their work. Photo by S. Boessenecker.

Our docents take photos and detailed notes to document their work. Photo by S. Boessenecker.

At least one of these skulls appears to represent the same species as the tusked waipatiid dolphin on display in our whale evolution gallery. Waipatiid dolphins were originally reported from the Oligocene of New Zealand – the first named species is Waipatia maerewhenua, named by R. Ewan Fordyce in 1994.

Our waipatiid dolphin already on display in the museum. Photo by S. Boessenecker.

Our waipatiid dolphin already on display in the museum. Photo by S. Boessenecker.

These dolphins were also common in the Oligocene seas near Charleston, and by preparing these skulls they are helping us to better understand their evolution. A big huge thank-you to our wonderful volunteers!

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Friday Fossil Feature – Thinking of a Good Walrus Pun is No Easy Tusk…

by Sarah Boessenecker (@tetrameryx) and Robert Boessenecker (@CoastalPaleo)

Happy Fossil Friday!

Did you know that walruses used to live in the Southeastern US? From about 4 million years ago to as recently as 300,000 years ago these tusked behemoths were inhabiting in the southern most regions of the North Atlantic – as far south as Florida!

A tusk in the hand is worth 2 in the bush? Photo by R. Boessenecker.

A tusk in the hand is worth 2 in the bush? Photo by R. Boessenecker.

Our Friday Fossil Feature today is a partial tusk from Ontocetus emmonsi, a rare Pliocene walrus found in deposits from the Lee Creek Mine in Aurora, North Carolina, recently donated to CCNHM by the estate of Rita McDaniel. Two more tusks are also present in our collection, and are from South Carolina.

Our newest acquisiton, from Lee Creek, at top; female tusk in middle, and male tusk at bottom, both from South Carolina. Photo by S. Boessenecker.

Our newest acquisiton, from Lee Creek, at top; female tusk in middle, and male tusk at bottom, both from South Carolina. Photo by S. Boessenecker.

Ontocetus has a long history; it was first described in 1859 by Joseph Leidy, based off of a partial tusk from the Yorktown Formation, collected by Ebenezer Emmons, and is now in the collections at the Smithsonian Museum of Natural History (USNM).  Emmons was a professor at Williams College in Massachusetts, and also the State Geologist of North Carolina from 1851-1863, and was honored with Ontocetus being named after him. Many other species of Plio-Pleistocene walruses from the North Atlantic were subsequently proposed, including: Alachtherium cretsii, Alachtherium antwerpiensis, Trichecodon huxleyi, Trichecodon/Odobenus antverpiensis, and Prorosmarus alleni.

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The holotype specimen of Ontocetus emmonsi, from USNM. Photo by R. Boessenecker.

A juvenile maxila and tusk, at USNM. Photo by R. Boessenecker.

A juvenile maxila and tusk, at USNM. Photo by R. Boessenecker.

A monograph published by Naoki Kohno and Clayton Ray (2008) in the Lee Creek Volume IV through the Virginia Museum of Natural History examined and reconsidered specimens of Ontocetus and other walrus material from Atlantic Pliocene deposits. They realized that many species that had been described and presenting problems for scientists were in fact the same species. Rules of zoological nomenclature dictate that if multiple names (synonyms) have been proposed for a single species, the oldest (and thus first proposed) name for a particular species is the correct one. In this case, Ontocetus emmonsi was the first name proposed for the extinct walrus from the Pliocene of the North Atlantic.

Through the simple act of recognizing that all these problematic species represented the same walrus, much confusion was resolved and the range and number of specimens was significantly improved. The larger sample now available from the Pliocene sediments along the North Atlantic margin (Florida, South Carolina, North Carolina, United Kingdom, Netherlands, Belgium, and Morocco) now indicates that Ontocetus was widely distributed down to subtropical latitudes, had shorter and more highly curved tusks than modern walrus, had a more elongate skull, and may have been slightly larger. This walrus had far more of a presence than previously thought in the Pliocene!

 

Further Reading:

J. Leidy. 1859. [Remarks on Dromatherium sylvestre and Ontocetus emmonsi]. Proceedings of the Academy of Natural Sciences of Philadelphia 1859:162

D. P. B. Erdbrink and P. J. H. Van Bree. 1986. Fossil cranial walrus material from the North Sea and estuary of the Schelde (Mammalia, Carnivora). Beaufortia 49(1):1-9

C. R. Harington. 1984. Quaternary marine and land mammals and their paleoenvironmental implications – examples from Northern North America. Special publication of the Carnegie Museum of Natural History 8:511-525.

N. Kohno and C. E. Ray. 2008. Pliocene walruses from the Yorktown Formation of Virginia and North Carolina, and a systematic revision of the North Atlantic Pliocene walruses. Virginia Museum of Natural History Special Publication 14:39-80

K. Post. 2004. What’s in a name: Alachtherium cretsii, de Pliocene van de Nordzee. Grundboor & Hammer 58:70-74.

L. Rutten. 1907. On fossil trichechids from Zeeland and Belgium. Proceedings of the Royal Netherlands Academy of Arts and Sciences 10(1):2-14 

A.E. Sanders. 2002. Additions to the Pleistocene mammal faunas of South Carolina, North Carolina, and Georgia. Transactions of the American Philosophical Society 92:1-152.

 

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Friday Fossil Feature – An investi-Gator of the Oligocene of South Carolina

by Sarah Boessenecker (@tetrameryx)

Happy Fossil Friday!

Dentary of Gavialosuchus americanus. Photo by S. Boessenecker.

Dentary of Gavialosuchus americanus. Photo by S. Boessenecker.

This week we take a look at Gavialosuchus americanus.

Gavialosuchus americanus wasn’t actually an alligator; rather, they were more closely related to today’s gharials and crocodiles. Crocodile puns, however, don’t seem to have the same bite as alligator puns.

Gavialosuchus was a long-snouted crocodylian. Photo by S. Boessenecker.

Gavialosuchus was a long-snouted crocodylian. Photo by S. Boessenecker.

Gavialosuchus lived in estuaries and coastal environments rather than the freshwater habitats its modern relatives prefer; it also grew quite large, growing in excess of 20 feet. That’s as big as today’s saltwater crocodiles!

For prey of Gavialosuchus, a view like this would likely be your last. Photo by S. Boessenecker.

For prey of Gavialosuchus, a view like this would likely be your last. Photo by S. Boessenecker.

Its diet likely consisted of animals commonly found as fossils here in South Carolina, including the Charleston area. These include the dugong Metaxytherium, the river dolphin Pomatodelphis, and shallow water sharks. As Gavialosuchus was a polyphylodont similar to its modern relatives, it was able to constantly replace its teeth throughout its lifetime. Because of this, shed teeth are very commonly found by those hunting for fossils.

 

Teeth of varying ages and sizes, as Gavialosuchus was constantly replacing them. Photo by S. Boessenecker.

Teeth of varying ages and sizes, as Gavialosuchus was constantly replacing them. Photo by S. Boessenecker.

A new tooth emerging. Photo by S. Boessenecker.

A new tooth emerging. Photo by S. Boessenecker.

 

Recently, there’s been some controversy about this taxa; some scientists think that it is the same species as a previously named fossil Thecachampsa americana, as well as a handful of other taxa – this just goes to show the more specimens we find of an extinct animal, the larger our data set becomes, and we’re able to piece together better how these animals lived and evolved. Science is always evolving as we learn more!

Further Reading:

Erickson, Bruce R.; Sawyer, Glen T. (1996). The estuarine crocodile Gavialosuchus carolinensis n. sp. (Crocodylia: Eusuchia) from the late Oligocene of South Carolina, North America. The Science Museum of Minnesota St. Paul, Minnesota Monograph 3, Paleontology. St. Paul: The Science Museum of Minnesota. pp. 1–47.

Myrick, A.C., Jr. (2001). “Thecachampsa antiqua (Leidy, 1852) (Crocodylidae: Thoracosaurinae) from the fossil marine deposits at Lee Creek Mine, Aurora, North Carolina, USA”. Smithsonian Contributions to Paleobiology 90: 219–225.

 

 

 

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Friday Fossil Feature – Kogia let us tell you about earbones again?

By Robert Boessenecker (@CoastalPaleo) and Sarah Boessenecker (@tetrameryx)

For Fossil Friday this week here’s a couple of pygmy sperm whale earbones from the recently acquired Rita McDaniel collection at the Mace Brown Museum of Natural History. McDaniel led mine tours into the Lee Creek Mine (Aurora PCS phosphate mine, North Carolina) for many years, and collected a substantial amount of fossil material from the middle Miocene Pungo River Limestone and the younger overlying lower Pliocene Yorktown Formation. The Yorktown Formation has produced one of the most important assemblages of Pliocene marine vertebrate fossils worldwide and is an important point of comparison for students of shark, fish, seabird, seal, and cetacean evolution.

Some of the earbones in our collection; modern Kogia on the left, and Kogiidae indet. on the right. Photo by Sarah Boessenecker.

Some of the earbones in our collection; modern Kogia on the left, and Kogiidae indet. on the right. Photo by Sarah Boessenecker.

The modern dwarf and pygmy sperm whales (Kogia simus and Kogia breviceps) are tiny sperm whales clocking in at only 2.5-3.5 meters long (approximately the size of a bottlenose dolphin), a fraction of the size of the more publicly known giant sperm whale (Physeter macrocephalus ) of Moby Dick fame (20 meter length). Both species of Kogia are rarely seen alive, and little information is known about their behavior or ecology. Similar to the extant giant sperm whale the fossil record includes many other extinct genera within the family Kogiidae and demonstrates that they evolved from somewhat larger ancestors, with a higher diversity in the late Miocene and Pliocene.

The modern pygmy sperm whale; an elusive creature, most of our knowledge about them comes from strandings rather than live sightings. Image Source.

The modern pygmy sperm whale; an elusive creature, most of our knowledge about them comes from strandings rather than live sightings. Image Source.

At the Lee Creek Mine, a larger kogiid whale is known from a well-preserved skull from the Pliocene Yorktown Formation – Aprixokogia kelloggi – which primitively retained upper teeth. When this species was named, hundreds of isolated well-preserved inner ear bones (periotics/petrosals) were also known, but not associated with the skull. Because of the lack of overlapping parts, the earbones were simply identified as Kogiidae indeterminate. These earbones are quite a bit larger and more robust than extant Kogia spp., which has dainty little periotics.

The 3 modern species of sperm whales. Image source.

The 3 modern species of sperm whales. Image source.

A new study published by Jorge Velez-Juarbe, Aaron Wood, and Catalina Pimiento reevaluates kogiid earbones from the Yorktown Formation of North Carolina and Bone Valley Formation of Florida, and reports previously unrecognized periotics of modern Kogia from the Yorktown Formation, preserved side-by-side with a larger, less modernized pygmy sperm whale (Aprixokogia). These earbones of Kogia are much more rare than the larger variety, and we were lucky enough to receive one of these in our recent donation. Check out our earbone of Kogia side by side with the larger unidentified kogiid – a puzzle answered by this new paper from our colleagues!

Further Reading:

Jorge Vélez-Juarbe, Aaron R. Wood & Catalina Pimiento (2016): Pygmy
sperm whales (Odontoceti, Kogiidae) from the Pliocene of Florida and North Carolina, Journal
of Vertebrate Paleontology, DOI: 10.1080/02724634.2016.1135806 [Full Article]

 

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How we spent our Spring Break

By Sarah Boessenecker (@tetrameryx)

Spring break: a time for fun, relaxation, road trips, and partying… for students at least. For visiting researchers Dr. Morgan Churchill and Dr. Brian Beatty, it was a prime time to visit the collections at CCNHM and work on some of the fossils we have here.

Churchill, a post-doc student at New York Institute of Technology (@nyit) was in Charleston all last week researching the cetacean material we have here at CCNHM. Using a 3D laser scanner, Churchill was able to ‘map’ the skulls of various whale and dolphin specimens, to be used for studying the evolution of cranial telescoping of early whales and dolphins. Churchill has visited numerous museum collections to obtain data from multiple specimens to be used for many future projects.

Morgan Churchill prepping an Eosqualodon for laser scanning. Photo by R. Boessenecker.

Morgan Churchill prepping an Eosqualodon for laser scanning. Photo by R. Boessenecker.

Laser lighting on Eosqualodon makes for a menacing sight. Photo by R. Boessenecker

Laser lighting on Eosqualodon makes for a menacing sight. Photo by R. Boessenecker.

Morgan Churchill scanning one of our toothed mysticetes. Photo by R. Boessenecker.

Morgan Churchill scanning one of our toothed mysticetes. Photo by R. Boessenecker.

“Laser scanning is a powerful tool that allows 3D models to be built of any specimen, which can then be uploaded onto the internet and shared with researchers around the world,” said Churchill, who will be visiting the Charleston Museum later this summer as well, where he will work to train the staff there on 3D scanning.

Brian Beatty, another researcher at NYIT visited the CCNHM collections later in the week. Beatty works with dentitions of dugongs, sirenians, and whales, and came to look specifically at some of our toothed mysticetes.

Morgan Churchill and Brian Beatty during the scanning of our Micromysticetus baleen whale braincase. Photo by R. Boessenecker.

Morgan Churchill and Brian Beatty during the scanning of our Micromysticetus baleen whale braincase. Photo by R. Boessenecker.

Brian Beatty describing the how's and why's of tooth measurements. Photo by R. Boessenecker.

Brian Beatty describing the hows and whys of tooth measurements. Photo by R. Boessenecker.

Brian Beatty measuring the jaws of one of our toothed mysticetes. Photo by R. Boessenecker.

Brian Beatty measuring the jaws of one of our toothed mysticetes. Photo by R. Boessenecker.

“I came to Charleston from Long Island, NY solely to study the collection of fossil whales at the Mace Brown Museum of Natural History,” said Beatty. “I’m working with colleagues in NY and Charleston to understand the early diversification of whales. The specimens in Charleston are pivotally important to this study, as they represent an unusually diverse group of the earliest forms of toothed and baleen whales, including unusual primitive toothed baleen whales. As a specialist on teeth, this collection is especially interesting and compelling. There is no collection like this anywhere else.”

The collections at CCNHM are one of only a handful of locations in the world to house Oligocene whales and dolphins, and these specimens are key towards understanding the early evolution of baleen whales and toothed whales (dolphins, porpoises). We can’t wait to see the results from this visit, and any future visits!

 

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Friday Fossil Feature – Holy Bullae, Batman!

By Sarah Boessenecker (@tetrameryx)

Happy Fossil Friday!

Recently, CCNHM received a large donation of fossils from the famous PCS mine in Aurora, NC – known to paleontologists as Lee Creek. This is a mecca for fossils from the mid-Miocene through the early Pliocene (~15 – 3 million years ago), and include fossils from pinnipeds, cetaceans, birds, sharks, and sea turtles.

Some of the most common fossils found are cetacean tympanic bullae and periotics – ear bones!

Some of the many bullae from the Lee Creek Mine. Photo by S. Boessenecker

Some of the many bullae from the Lee Creek Mine. Photo by S. Boessenecker.

Whales hear differently from land animals, as sound travels close to 4 times faster through the water. Why does this matter? When we hear something, it is caused by sound waves that travel through the air. Sound travels fast, (332 meters per second!) but it is still slow enough that it hits each of our ears at slightly different times. While these differences are minute, our brain is able to process it and calculate which ear the sound waves hit first – enabling us to pinpoint the direction the sound is coming from.

Sound travels at different speeds through different mediums. Image Source.

Sound travels at different speeds through different mediums. Image Source.

When we hear a sound, it is caused by sound waves vibrating through the air, entering our ear canal, and striking our tympanic membrane – the ear drum. The ear drum vibrates, causing tiny bones in the inner ear to move, and these vibrations are translated into nerve impulses the brain interprets as sound.

How human hearing works.

How human hearing works. Image Source.

 

However, water is much more dense than air, and this allows sound waves to travel much more quickly though it. If you’ve ever been swimming and submerged your head, any sounds you hear seem to be surrounding you; it’s impossible to tell what direction the sound is coming from. The sound is simply moving too quickly through the water for your brain to be able to differentiate which ear the sound wave hits first. Whales have adaptations to deal with this though.

Water, bones, and muscle all have similar densities – much higher than air. This means that when sound travels through the water and strikes an object, such as a whale, it travels at the same speed through all the bone, muscle, and connective tissue, and as such reaches both ears at the same time. To combat this, whales have adaptations that allow them to still have directional hearing.

Sound travels through the bones and mandibular fat pad. Image Source.

Sound travels through the bones and mandibular fat pad. Image Source.

Whales have evolved multiple sinus cavities around their ear bones – these air cavities cause acoustic impedance (sound waves bouncing) and as such some sounds are reflected back into the water and scattered. However, whales have also evolved a mandibular fat pad – a large, fatty mass in the lower jaw that acts like our own ear pinna (our outer cartilaginous ear). Sound travels up through the skull and jaw, is channeled into the mandibular fat pad, and is then focused and funneled into the tympanic bulla, which is attached to the malleus (the stirrup in human ears). The malleus vibrates into the cochlea, moving liquid in the canal (just as in humans) over little hairs (cilia) and the brain interprets these movements as sounds.

All of these adaptations also mean that whale ear bones tend to be larger and more dense than those of terrestrial mammals, and as such tend to preserve very well in the fossil record. Since they are not attached to the skull and are simply embedded in soft tissue, they often drop out of decomposing carcasses and tend to be found in concentrated horizons – bone beds. The Lee Creek Mine includes several bone beds, with a rich assortment of earbones from many different species of cetaceans. Be sure to visit CCNHM soon to see the upcoming display featuring many of the fossils from the Lee Creek Mine!

 

Further Reading:

Ketten, D.R. 1994, “Functional analyses of whale ears: Adaptations for underwater hearing.” I.E.E.E. Proceedings in Underwater Acoustics 1: 264-270.

Ketten, D.R. 2000, “Cetacean Ears.” In: Hearing by Whales and Dolphins (W.W.L. Au, A.N. Popper, and R.R. Fay, eds.) Springer-Verlag, Inc., New York, NY. p. 43-108.

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Friday Fossil Feature – ammonite or am I right?

By Sarah Boessenecker (@tetrameryx)

Happy Fossil Friday!

Cleoniceras sp., from the lower Cretaceous of Madagascar. The 'ceras' in the name is greek for 'horns.' Photo by S. Boessenecker

Cleoniceras sp., from the lower Cretaceous of Madagascar. The ‘ceras‘ in the name is greek for ‘horns.’ Photo by S. Boessenecker

Ammonites are an amazing group of fossils that can be found all over the world today. They were an incredibly diverse group of cephalopods, arising in the early Devonian (~400 million years ago) and they lived until the end of the Cretaceous period (65 million years ago). While they look similar to the modern nautilus of today, these mollusks are actually most closely related to squids, octopus, and cuttlefish. The term “ammonite” actually dates back from Ancient Greece, when Pliny the Elder thought the resembled the horns of the Egyptian god Ammon – he called these fossils ‘ammonis cornua.

Ammonites are often used as index fossils for paleontologists, as different genera evolved and died out rather quickly in geologic time. As such, they are very useful for biostratigraphy.

We have an amazing collection of ammonites here at the CCNHM, so be sure to take a moment to discover them all on your next visit!

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Friday Fossil Feature – The Tully Monster

By Sarah Boessenecker (@tetrameryx)

Happy Fossil Friday!

Here at CCNHM we have a wonderful collection that was donated from the Mazon Creek Fossil Beds in Illinois. These beds have provided hundreds of specimens of strange organisms that have been exquisitely preserved for over 300 million years!

The beds date from the Pennsylvanian, and form a lagerstätte – a sedimentary structure known for ideal conditions that preserve fossils, especially those of soft-bodied organisms. Anoxic environments prohibited the growth of bacteria and the decomposition of bodies, and as such we can see the structures that would not normally be preserved in other environments.

Tullimonstrom gregarium, the Tully Monster. This strange creature is unique to the Mazon Creek fossil site. Image by S. Boessenecker

Tullimonstrum gregarium, the Tully Monster. This strange creature is unique to the Mazon Creek fossil site and remains a bit of an enigma to paleontologists to this day. Image by S. Boessenecker.

An artist's reconstruction of what the Tully Monster may have looked like in life. Image Source.

An artist’s reconstruction of what the Tully Monster may have looked like in life. Image Source.

The name ‘Tullimonstrum’ comes from its first discoverer Francis Tully, with ‘monstrum’ referring to its bizarre bodyplan. It’s so different from anything seen today, scientists have been unable to determine which phylum it should be placed in! While incredibly common from the Mazon Creek fossil site, (gregarium is referring to the abundance of this fossil) it has never been found in any other locality.

 

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