Monday, November 24, 2025

The Boesseneckers in Britain: Annual Meeting of the Society of Vertebrate Paleontology, 2025 - Birmingham, UK

Incredible northern lights illuminated our path across the North Atlantic - here photographed with a five second exposure.

This one is more of a travelogue post than a scientific one - Sarah and I have just returned from an excellent meeting of the Society of Vertebrate Paleontology, or SVP. This year's SVP meeting was held in Birmingham in the UK, an industrial city in the midlands which, I did not realize until just now, is the second largest city in Britain after London. Birmingham was a veritable maze of wet brick underneath a gray, foggy sky - and while we did not go to the 2024 meeting in Minneapolis, I have to say that this was the worst weather I've ever experienced at a conference (even Seattle in October for GSA was better). I'm not kidding, the cold was bone-chilling! The incessant drizzle and penetrating damp cold really reminded me of our time in New Zealand.

 

The conference is four days, with oral presentations from 8am to 4pm, and a two hour poster session from 4:30-6:30pm; at my first SVP, there were only two poster sessions, which by the time of my third or fourth meeting, had rapidly consumed the afternoons of all four days as the conference grew in attendance. The talks are usually organized by topic, encouraging attendees to relax in one hall for the morning or afternoon; this year, some of these sessions received whimsical names, to the chagrin of some serious paleontologists - e.g. "crocs and turts". 

Into the early 2000s the conference was small enough to fit on a college campus, and sessions were held literally in university lecture halls. I was born too late for this, as my very first meeting, the 2005 meeting in Mesa, Arizona (a suburb of Phoenix) was one of the first ones held at a convention center. The last overseas SVP I attended was in 2009 at Bristol - was a brief return to the old University host model, which some of the older attendees enjoyed, but ultimately resulted in talks that were far too cramped. The society has been dealing with growing pains since my first couple of meetings, most famously manifested in some pretty severe publication 'logjams' (circa 2008-2012 or so) in the society's flagship journal, the Journal of Vertebrate Paleontology. For a while papers would wait 16-20 months between acceptance and publication as the journal, and the society, ballooned.

We were already supposed to be in Laguna Beach for the wedding of my cousin Danny and his fiance Jeanne, so we opted to get direct flights out of LAX - and fortunately were able to fly out Monday after the Saturday wedding, so we were no longer, ahem, quite so dehydrated. We flew out at about 4, watched some movies, and around four hours into the flight, began to see a glow on the horizon. We were flying over Hudson Bay and northern Quebec, and could make out the Aurora borealis extremely clearly. From the airplane window we could make out a silvery veil - and with only 5-6 second exposures using "night sight" on our phones, the aurora rapidly became obvious as a bright green color. We could see the aurora quite clearly until nearly dawn, just off the southeast coast of Greenland. What's incredible is that the light show really started after we landed, and we saw all sorts of incredible photos taken from as far south as southern California as one of the most powerful geomagnetic storms ever was unfolding. We would have seen the aurora from Birmingham if it wasn't for that layer of thick, gray cloud.

 Sarah getting off the Heathrow Express at Paddington Rail Station.

We landed at Heathrow, took a few trains on the tube and ended up on the Chiltern line to Birmingham - where we slowly succumbed to sleep in awkward positions. When we arrived at our hotel, we were nearly immediately greeted by our colleague Dana Ehret from New Jersey - rather than going out drinking, we fell asleep nearly immediately.

 A pretty funny tongue in cheek memorial to Ozzy Osbourne outside a pub in Birmingham. Black Sabbath started in Birmingham in the early 1970s. Side note: if all you've ever heard from Black Sabbath is "Iron Man" or "War Pigs" I suggest giving a listen to Sabotage, Sabbath Bloody Sabbath, or Volume 4. A lot of their early stuff is like heavy metal blues and kicks ass.

The first day of the conference was great - we caught up with a bunch of old friends, and went to some talks on carnivores; just before lunch was a talk by James Napoli, which was of course embargoed (new territory for SVP - the entire abstract, and talk title, was redacted; still not sure how I feel about that). However, the publication for it had just come out in Nature, and was of course on the new findings about Nannotyrannus and Tyrannosaurus based on the "Dueling dinosaurs" specimen. The talk went long, so there was no opportunity for questions; I did not stick around for the second lecture.

 Yours truly looking extra serious at my poster presentation.

That afternoon I set up my poster in "pinniped alley" which, surprisingly, ended up being the most crowded and congested part of the poster session; some colleagues never made it by because it was too cramped. My colleagues had some great posters: Ana Valenzuela-Toro was next to me and had a poster presenting new data on the South American seal Kawas benegasorum; Lindsey Koper was next to her and had some new anatomical data on pinniped middle ear ossicles. Across the gap was a poster by Aussie colleagues on canine growth in pinnipeds, and another on bite force in pinnipeds by Arnau Bolet et al., and another on the function of the neck and sensitivity of the inner ear of pinnipeds by Julia Schwab and colleagues. 

I managed to chat quite a bit with Naoki Kohno - few paleontologists know more about otariids (and other pinnipeds) than him.

I presented my own poster on a rather cute little pair of fossil mandibles identifiable as the extinct fur seal Pithanotaria starri - nothing groundbreaking - but warranting a short manuscript I'll get submitted in the coming weeks. The specimen is one that I collected myself - it's always quite satisfying to present on fossils you've found yourself; I've not managed to present on fossils I myself have discovered since the 2011 meeting in Las Vegas. More critically, I wanted to do something low key and I also haven't done a poster presentation in nearly 15 years (ironically, also the 2011 Las Vegas meeting). I was able to have a long chat about the fossil, and other otariids, with my colleague Naoki Kohno from Japan. At one point he gestured at one of my figures showcasing some other fossil otariids for comparison, and remarked that he didn't recognize any of them from his previous research visits to UCMP at Berkeley. I explained that the specimens he was unfamiliar with were all ones that I had discovered in the 2000s - I felt quite chuffed at that. 

 The welcome reception at the Lapworth Museum, University of Birmingham.

That evening there was a bit of a chaotic migration to the host institution - the Lapworth Museum at the University of Birmingham - and many of the non-brits had a bit of an interesting time (from amusing to frustrating) getting to the welcome reception. We arrived at the Lapworth Museum half starved and wishing equally for drink and were given confusing instructions to where the food was - wandering in a bit of a jetlagged stupor through this 19th century set of attached buildings. We finally found long 'queues' for three food trucks outside; curry, fish and chips, and bangers and mash were the options. I had had fish and chips the night before, and I fully expected to rely on a bounty of Indian food later in the week, so I opted for bangers and mash - not bad. We caught up with more friends after eating - and retired to the hotel bar with some of our good friends from the states.

 My academic "niece" and "nephew" - graduate students Yi-Yang Cho (left) and Yi-Lu Liaw (bottom), students of my doctoral program cohort Cheng-Hsiu Tsai; his students were just as infectiously enthusiastic as he is. My own former student, Ann-Frances Cowgill, is behind Sarah and I.

I sat through the entire 'methods' symposium, formerly known as the preparator's session; on the left, Martin Chavez-Hoffmeister discusses fossil monitoring in Chile and showcases the spectacular skull of Pelagornis chilensis; on the right, our good friend Lee Hall summarizes challenges and opportunities with the closure, and reopening, of the Museum of the Rockies prep lab during and after Covid.

The second day was for the whales. A few talks on fossil whales stood out: the first was by Eli Amson and colleagues on the evolution of the brain and bone mass increase in protocetid whales. I also finally managed to meet Eli during this meeting - despite occasionally reviewing his papers for nearly 15 years! After his talk, Piero Giuffra - a PhD student from Peru who is in the Mark Uhen lab at George Mason University - gave a fascinating talk on a basilosaurid whale with unusually well-developed hindlimbs from the Eocene of Peru; the specimen also retains a sacral vertebra and a wide pelvis, suggesting a more complicated evolutionary pattern of hindlimb reduction than previously considered. Next up was a talk on an ecomorphological analysis by the infectiously enthusiastic Rebecca Bennion on fossil odontocetes from the early Miocene Chilcatay Formation of Peru; we hosted Rebecca during a research visit in Charleston back in 2019 or so, and it's been a pleasure seeing her career blossom in the time being! Last up was a talk by another Uhen lab doctoral student, Rebecca Strauch - evaluating a number of different anatomical features previously used to infer suction feeding in toothed whales. I quite enjoyed the talk, and was pretty chuffed to see that our little toothless dwarf dolphin, Inermorostrum, managed to be strongly predicted as a suction feeder based on an incomplete set of her eight or so predictive features.

Sarah with a gorgeous bust of the raoellid proto-whale Khirtharia sculpted by Maeva Orliac for for her poster on raoellid morphology, and 3D printed to its shockingly tiny life-size. 

I met a number of other colleagues for the first time, mostly Europeans - fellow carnivore specialist Dario Estraviz Lopez from Portugal, Jonas Hakkens and Jelle Reumer from the Netherlands, and Shorouq AlAshqar from Mansoura University - who stepped in to present her former labmate Abdullah Gohar's poster on a gigantic protocetid pelvis from Egypt (I previously collaborated with Abdullah and the Mansoura team on Phiomicetus). I managed to meet my academic "niece" and "nephew" - Yi-Yang Cho, and Yi-Lu Liaw, two doctoral students of my dear friend and Otago labmate Cheng-Hsiu Tsai. They brought greetings and some new lab swag from Tsai, who manages to produce new laser-cut wooden drink coasters for virtually every new paper from his lab; I believe I got three or four different coasters, one of which figured our newly described Fucaia humilis, for example. Perhaps most critically, however, I finally met two students from the Fordyce lab: Ambre Coste, who published the "waipatiid" tusked dolphins Nihoroa and Nihohae from her Ph.D. research, and Katie Matts, who was essentially one of Ewan's last Ph.D. students before he passed. Katie worked on giant penguins in the genus Platydyptes, which were the most common penguins in the Oligocene Otekaike Limestone. Ironically, Platydyptes were quite a bit smaller than Kairuku from the Kokoamu Greensand and the spectacular Pachydyptes from the Ototora Limestone, and despite being larger than modern emperor/king penguins (Aptenodytes), I always thought of Platydyptes as the small ones.

 
Hung out a bit with my NZ colleague Alan Tennyson - his first SVP! He loved it. He's usually gone to ornithology conferences and remarked upon how interesting it was to have research on all sorts of other groups to go soak up. 

 Other colleagues I had not seen in quite some time. Chief among these were Gabriel Aguirre-Fernandez, one of my Otago labmates; we caught up quite a bit and chatted about our time in New Zealand. I also spent a bit of time catching up with Alan Tennyson - a paleornithologist at Te Papa Tongarewa in Wellington, and one of my most valued colleagues I made during my time down under. We chatted about recent flare ups regarding the company Colossal and our good friend Nic Rawlence back at Otago. 


 A special day at Leicester celebrating Sarah's very, very belated graduation. The irony is that, had she gone in 2020, she would have only been able to bring along two guests; instead, we had our closest friends along for the day. On the far left: Ash Poust; on the right: Ashley and Lee Hall.

Perhaps a more critical goal in visiting the UK was a long-delayed visit to Leicester - Sarah earned her master's in Museum Studies from the University of Leicester in 2020 as part of the distance learning program - one of the more prestigious museum training programs out there. Sadly, though, you read that right: Sarah was in the class of 2020. Her graduation was cancelled, and she felt like it had been stolen from her. As soon as we had made plans to attend the SVP meeting in Birmingham, we planned on bringing her Leicester robes and taking some graduation photos with us. We invited our closest friends - Ash Poust, Lee Hall, and Ashley Hall - and took the train to Leicester the day after the conference. Leicester was a breath of fresh air after Birmingham - lots of old buildings in good shape, and plenty of trees and greenery - a far cry from the endless wet brickscape of Birmingham.

Jim Butler - also of the Leicester class of 2020 - gave us a historical/archaeological walking tour of Leicester. Here's "Jewry wall", a first century Roman wall - and the largest free-standing bit of Roman masonry in the British Isles; the arches denote that this was the edge of a building and not part of the town wall, probably a basilica. The flattened red 'bricks' are the same sort you see in Rome along some buildings in the forum and the Aurelian walls.

 

This section of the wall, like many Roman buildings preserved elsewhere, was probably maintained by its close contact/association with a church - St. Nicholas' church can be seen on the right, an Anglo-Saxon church from the 'dark ages' (late Antiquity) with an added Romanesque tower (Norman period) and later Gothic additions. There aren't many Anglo-Saxon churches left, even in part.

We were picked up from the train station by Sarah's friend Jim Butler, a historian who gives fantastic walking tours of Leicester - one of the oldest cities in the midlands - founded in the mid first century AD as Ratae Corieltauvorum by the Romans. Given my interest in Roman history, I had loads of questions for Jim on our walking tour. We visited the Roman ruins at Jewry Wall, and a beautiful little Anglo-Saxon church called St. Nicholas Church just next to it, with a lovely Romanesque tower with recycled Roman bricks - like a miniature version of the forum.

 The home that Richard and David Attenborough grew up in, right on U. Leicester campus.

Sarah pointing out some carved notes made by the Attenboroughs as children (or, I hope when they were children!)

Sarah tossing her mortarboard in front of the Museum Studies department.

Sarah in her full regalia at her very late graduation. I'm so proud of her.

The Guildhall in Leicester, a spectacular medieval timberframe building started in 1390, and much of the remainder dating from the 1400s.

3D printed copies of the skeleton of King Richard III. On the right the vertebrae are in articulation, showing his advanced scoliosis - a far cry from the hunchbacked depiction invented by later writers like Shakespeare; his physical deformity was probably completely unknown to anyone outside the royal family until he was cut down and stripped naked at the climax of the Battle of Bosworth Field in 1485.

On campus, we visited the house that the Attenboroughs grew up in (yes, David, and Richard),  We met outside the Museum Studies department and I gave a clumsy but heartfelt, off-the-cuff commencement speech, with some kind words added by Ash and Lee. By day's end, we made sure to visit both the final resting place of King Richard III - discovered in 2012 underneath a parking lot - and the fantastic Richard III museum a hundred yards away. We said our goodbyes to Jim, Lee, and Ashley, and Sarah, Ash, and I hopped aboard a train to London. 

 Big Ben and the Houses of Parliament from Westminster Bridge. 

Tower Bridge, just a short distance downstream along the Thames - photographed here from the inner curtain wall of the Tower of London. Note: this is NOT the famous London Bridge - London Bridge was torn down and this replaced it.

  

Westminster Abbey, inside and out: almost a cathedral. Perhaps one of the most important churches on earth, its historical significance disproportionately related to its modest size.

 

Sarah trying to smile, rather than ugly cry, at Stephen Hawking's tomb at Westminster - one of her heroes.

 

Charles Darwin and his good friend Charles Lyell are interred just a few meters apart at Westminster Abbey. I had seen Darwin's before, but this was my first time seeing Lyell's.

Looking more closely - the tomb of Lyell is absolutely studded with fossil crinoids. How fitting!

I had no idea that Winston Churchill was an artist - his landscapes are actually quite nice. He retreated to painting after the failure of the Dardanelles campaign in World War 1 and after electoral losses just after the war. I can relate to that.

I had no idea until Lucy mentioned that the temporary exhibit at the National Gallery included some pieces by Joseph Wright of Derby, including this one - A Philosopher lecturing on the Orrery - depicting an aged professor giving a lecture about the solar system, scowling at his student, making sure he is taking notes, while a bunch of students appear bored as hell - aside of course, for a couple of young children illuminated in the center.

I've wanted to see this damn painting for like 20 years. JMW Turner's masterpiece, The Fighting Temeraire, tugged to her last berth to be broken up. You may remember it from the movie Skyfall.

Sarah was thrilled that she finally got to see the only copy of Beowulf - the Nowell Codex, a manuscript written in Anglo-Saxon (Old English) around the year 1000. It's not that other copies of Beowulf are known - it is only known from this single codex. Imagine what other literary works from the "Dark Ages" were lost.

We spent two fantastic days in London - the first day we explored far and wide with Ash and his partner, Lucy Chang, a curator at the California Science Center in LA. We visited Westminster Abbey, where Sarah paid homage to Stephen Hawking's gravesite, and I found Charles Lyell - unceremoniously covered by a table. Shortly thereafter we went to the Cabinet War Rooms and the Churchill Museum, then walked through Whitehall and made a visit to the National Gallery to see some of the most famous paintings by William Turner and also some Dutch Renaissance masterpieces. We rounded out the day with a late night visit to the British Library where we saw the only surviving known copy of Beowulf (the work is not duplicated in any other Anglo-Saxon, or indeed, Scandinavian, manuscript or codex). 

Two saurischian dinosaurs hanging out in front of the NHM on a very, very chilly morning.

The largest marine reptile on display in the "Mary Anning" hallway, a cast of the holotype skeleton of the short necked plesiosaur Rhomaleosaurus cramptoni, from the Lower Jurassic Whitby Mudstone of Yorkshire.  

One of the earliest discoveries of a plesiosaur - Plesiosaurus macrocephalus - the original specimen, found by none other than Mary Anning at Lyme Regis in the Lower Jurassic Blue Lias. 

One of the most famous examples of a pregnant ichthyosaur - a specimen of Stenopterygius quadriscissus with a fetus that appears to be in the process of being expelled from the mother's body at the time of death and burial; Lower Jurassic, Holzmaden, Germany.

One of the earlier discoveries of a gigantic ichthyosaur - Temnodontosaurus platyodon, Lower Jurassic, Blue Lias, Lyme Regis.

A pint sized paleontologist admiring some pint sized ichthyosaurs.

Sarah and I were on our own the next day, which was spent chiefly at the Natural History Museum just a block away from our hotel. I had never seen the hallway stuffed with articulated skeletons of Jurassic marine reptiles, many of which were finds made by Mary Anning. I had made it through the confusing and famously strange dinosaur hall at NHM, twice - and ended up somehow skipping this hall entirely both in 2003 with my family and in 2009 with Ash Poust.

 Sarah admiring the London specimen of Archaeopteryx lithographica - the earliest known bird. The counterslab is out of frame to the right. I've seen it before, but this display is vastly superior to the old one.

 A spectacular original (but composite, I think) skeleton of the Dodo from the island of Mauritius in the Indian Ocean.

A lovely taxidermied great auk, Pinguinus impennis. The largest alcid species was hunted extensively from the Medieval period onward for its feathers, considered the finest for pillows, and eventually to extinction in the mid 19th century. The last mated pair were thought to be witches, placed in burlap sacks, and bludgeoned.

The lovely skeleton of "Hope" the blue whale, the replacement for "Dippy" the Diplodocus. As a whale guy, and veteran dinosaur hater, I approve.

 

"Sophie" the Stegosaurus on display at the NHM.

The NHMUK skeleton of the Steller's Sea cow, Hydrodamalis gigas. There are just shy of 30 such skeletons in various museums, but most of these are composite skeletons.
 

And a closeup of the skull of the NHMUK Hydrodamalis.

 

One of the surviving casts of Prosqualodon davidis, a large, short-snouted Squalodon-like odontocete from the lower Miocene of Tasmania. The original skull was lost at some point after the 1940s. I've examined a cast at U. Otago. In an odd historical twist, it was named by the son of famed Robin Hood actor Errol Flynn.

The paratype (not a cast - the real deal!) mandible of Pappocetus lugardi, a rather enormous (Dorudon-sized) protocetid from the middle Eocene of 

We also made our way upstairs to the new "Treasures" gallery of the NHM, which had the original composite skeleton of a dodo, a lovely taxidermied great auk, the London Archaeopteryx and its counterslab, some of Gideo Mantell's original Iguanodon teeth, and even some of Darwin's pigeons. I was also keen to get a bunch of photos of "Hope" the blue whale, now suspended from the ceiling, a replacement for the NHM Diplodocus, aka "Dippy". We also got to see the newly installed Stegosaurus specimen "Sophie", which was much smaller than I expected!

 The White Tower - the first stone castle in the British Isles, and the Keep at the Tower of London. Initially constructed a few years after the Norman conquest of England in 1066, commissioned by William the Conqueror. The windows and those silly little turrets were added centuries later.

St. Paul's cathedral lit up at twilight.

We had initially planned on visiting the Tower of London and the British Museum that afternoon but spent too long at the NHM (on brand for a couple of paleontologists), and so spent the rest of the afternoon at the Tower. We did manage to walk past St. Paul's cathedral in the evening before settling down for a bite to eat on our last night.

Monday, November 3, 2025

Acid preparation discoveries: earbones filled with fecal pellets

 

One of Terry Iversen's discoveries, a small toothed mysticete skull (eye socket to the left) sitting in an acid bath a few years ago.

I've been acid prepping fossils from the Pacific Northwest for about ten years now, and even in the most soluble rocks, not quite everything dissolves. Fossils sent to me by Jim Goedert, which we have livingly dubbed "whale mail", hail mostly from the the Makah Formation (early Oligocene, ~30-33 Ma) and the Pysht Formation ("middle" Oligocene, ~26-28 Ma). These two units are a calcareous siltstone - and while a lot of the rock dissolves away completely, there is always a bit of a muddy residue that remains. Clay minerals, after all, are insoluble. In some cases, some interesting structures can be left behind by the acid, which is harsh, chemically speaking, but extremely gentle physically speaking. Delicate latticework like micro-burrows can be left behind in rare circumstances. But, what I keep on finding are clusters of tiny little fecal pellets!

Sounds like Sh*t 



The tympanic bulla of Terry's baby simocetid specimen. The anterior part of the bulla fell off during acid preparation, and I took advantage of the missing part to photograph the pellets prior to reassembling it.

These clusters are usually no more than about a centimeter in diameter, and the pellets themselves are usually sort of egg-shaped but slightly elongated - roughly about 1-1.5 mm long and just slightly less than a millimeter in diameter. I've found these in over a half dozen specimens, and occasionally these clusters are just out in the matrix and might get scrubbed away by my tooth brush - after all, they are only slightly less soft than the insoluble clay I intermittently rinse and brush off of one of these fossils during an acid bath. However, they tend to stay in good shape in protected areas that don't get scrubbed hard - right up against nooks and crannies of the skull or vertebrae, inside the pulp cavities of incompletely formed teeth of juvenile dolphins, and, most recently, inside earbones! Last fall and earlier this year I prepared a lovely partial skull of a very young simocetid dolphin (probably Olympicetus) that was discovered by Washington collector Terry Iversen and given to me for study and preparation. He had discovered the corresponding halves of this concretion at different times, and matched them up based on the matching breaks on each half. I guarantee you'll be hearing about this exciting specimen again in the future.

Two clusters of fecal pellets inside the tympanic bulla of an Oligocene simocetid dolphin.

There happen to be fecal pellet clusters inside both tympanic bullae, within the tympanic cavity - this is essentially the same structure as your middle ear cavity, and the middle ear ossicles (stapes, incus, malleus) bridge the auditory gap between the tympanic bulla and the inner ear. It gives a bit of a new meaning to "that sounds like sh*t".

 The tympanic bulla of Iversen's simocetid after preparation and reassembly was completed.  

Fecal pellets expelled from a burrow, most likely from a Carolina ghost shrimp, Callichirus major. Folly Beach, SC.

Who dealt it? 

In all seriousness though, who is responsible for these cute little poops? Cylindrical to ovoid fecal pellets (which are differentiated from coprolites only based on size) are almost certain to represent some kind of burrowing invertebrate. Beach bums (like myself) with a habit of looking down might notice what I call "forbidden chocolate sprinkles" - 1-3 mm long sprinkle-like pellets ejected from sandy burrows on the beach at low tide, often forming a little mound or halo around a burrow. If you're lucky, you can even watch a little "eruption" of water from the burrow with these pellets flowing out and onto the beach - telltale evidence of someone cleaning house below. In these cases, the organism responsible is usually identified as a callianassoid ghost shrimp; the photo above is likely evidence of a Carolina ghost shrimp. If you notice, these are strictly cylindrical with flat or "chopped" ends - quite unlike the egg-shaped pellets I have found.


A single fecal pellet - Coprulus oblongus - imaged using a scanning electron microscope or SEM. From Godfrey et al. (2022).

Trace fossils are given binomial names, which can cause some confusion as trace fossil naming (ichnotaxonomy) is based entirely upon superficial similarities and differences as the practice is entirely descriptive. The major tenet of ichnology, or the study of trace fossils, is that 1) the same individual organism can make many different traces during its life and 2) many different species can make the same trace. That being said, the shape of these pellets clearly identify them as Coprulus oblongus - a fecal pellet type that goes back to the Cambrian period. Modern groups that produce similar pellets in the ichnofamily Coprulidae include polychaete worms, acorn worms, gastropods, and tunicates. In a paper I'll mention shortly, the presence of these undisturbed clusters of fecal pellets within relatively tight, difficult to access spaces like the inside of a tympanic bulla probably rules out ghost shrimp, which are, as adults, too large to fit into a space like this. Godfrey et al. (2022) suggested that similar finds from the Miocene of Maryland are perhaps more consistent with some kind of polychaete worm.

A fossil fish skull belonging to a stargazer (Astroscopus) from the Miocene of Maryland - filled with Coprulus fecal pellets. From Godfrey et al. (2022). 

Sh*t for brains?

A few years ago a puzzling specimen was reported by my colleague Stephen Godfrey, who published a neurocranium (braincase) of a fossil fish (a stargazer, Astroscopus) from the upper Miocene St. Mary's Formation of Calvert Cliffs in Maryland. Stephen has been publishing a series of wonderful short papers on some real taphonomic curiosities - but this is perhaps the strangest. The neurocranium appears to be completely filled to the brim with pellets identifiable as Coprulus oblongus. Judging from the photos above, you can tell that something narrow and flexible that could wriggle through small spaces would have been needed to produce fecal pellets like this inside the braincase! They note, however, that this is not the first example of clusters of fecal pellets inside other fossils - while it is the first reported inside a vertebrate, there are many older examples noted in the literature, including within echinoderms, cephalopods, gastropods, trilobites, and brachiopods.    


Why do we seem to preferentially find these fecal pellet clusters in close quarters like this? Are these evidence of scavengers feeding on ancient dolphins and fish? Is this evidence that these critters were deliberately hiding inside of tight, protected spaces? These ideas are of course certainly possible. Many polychaetes are simply "deposit feeders" - they burrow through the sediment and ingest organic-rich sediment, metabolizing the organic debris and passing the sediment (in the form of these pellets, which appear to basically just be mud shaped into pellets). It's certainly possible that these polychaetes were consuming part of the carcass during the "bonanza" phase of a whale or fish fall on the sea floor. The sheer volume of pellets inside the stargazer skull might suggest prolonged habitation of the braincase.

 

Clusters of fecal pellets preserved in association with clam shells and in some phosphatic nodules. From Godfrey et al. (2022).

However, there is a third option. I have definitely found just as many fecal clusters out in the siltstone concretions surrounding these little cetaceans from the Olympic Peninsula as I have inside the protected cavities of the skull (and teeth). These generally don't survive acid preparation, and I know that I have had to sacrifice some of these clusters to expose the bone - and in cases where leaving the clusters of pellets intact would not negatively affect interpreting the anatomy of the fossil dolphin, I've tried to preserve them in place. In other cases, the pellets have been found in close association with other fossils - including some clam fossils, or within small concretions; see the above examples figured by Godfrey et al. (2022). 

I think it is possible, if not likely, that such pellet accumulations are probably common throughout rock layers, but we might only pay attention to them or be able to even identify them in the field in rare occasions - either when they form an accumulation with a fossil we're interested in and already looking for - or in a small concretion large enough to spot at a brisk pace along a shoreline. "Hey, look, what's this weird thing?" The sheer majority of fossil collectors, even in a place like Calvert Cliffs where they are relatively informed, are just out looking for shark teeth. There's no problem with that. But, many collectors just aren't interested in even well-preserved mollusks. I am probably not paying enough attention to mollusks and ought to do better! 

On a similar level, these pellets likely disaggregate unless they're mineralized somehow, or, perhaps ironically, preserved within a cavity of another fossil that a fossil preparator is unlikely to empty out. Fecal pellets in a flat lying bed of sandstone or in a vertical cliff are unlikely to be identified let alone collected for study - and I'll cite myself as an example. I'll see something neat, that isn't quite within the scope of my studies, and say "oh neat!", snap a cell phone picture, and continue my search for marine mammal fossils.

In sum, I think that the way these things tend to erode like the siltstone and sandstone that often hosts these pellets means that we might only be paying attention to them under unusual circumstances. 

References 

Godfrey, S.J., A. Collareta, J.R. Nance. 2022. Coprolites from calvert cliffs: Miocene fecal pellets and burrowed crocodilian droppings from the Chesapeake Group of Maryland, U.S.A. Rivista Italiana di Paleontologia e Stratigrafia 128:69-70.