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Top 10 Open Access Fossil Taxa of 2017: Eekaulostomus cuevasae | PLOS Paleo Community

This is an article I wrote for the PLOS Paleontology Community blog, and am archiving it here. The original post was published on December 28, 2017, and can be accessed here.

With the end of the year comes the end to our countdown of the winners of the Top 10 Open Access Fossil Taxa of 2017. We appreciate everyone that took the time to read all of the contenders this year and to vote in the contest!

At Number 1 is the armored trumpetfish Eekaulostomus cuevasae from the Paleocene of Chiapas, Mexico! Published in the Open Access journal Palaeontologia Electronica by authors Kleyton Magno Cantalice and Jesús Alvarado-Ortega, this unusual fish is related to modern-day trumpetfishes and represents the oldest-known representative of the acanthomorph fish superfamily Aulostomoidea.

Artistic rendition of Eekaulostomus cuevasae, art by Brian Engh (dontmesswithdinosaurs.com).

I asked the lead author of this study, Dr. Kleyton Magno a few questions about this remarkable fish. Dr. Magno is currently a postdoctoral researchers at the Universidad Nacional Autónoma de México (UNAM).

PLOS Paleo: Tell me about the discovery of this fossil!

KM: In reality, this species was collected by Mr. Alberto Montejo, a local quarry worker and owner of the Belisario Dominguez paleontological site. In the annual expedition to Chiapas in 2010, he gave this specimen to Drs. Jesús Alvarado and Martha Cuevas, as a donation to the Paleontological National Collection (housed into the Instituto de Geología, Universidad Nacional Autónoma de México). This single specimen was found just at the end of a hard fieldwork day, when a tropical storm was about to start. Then, Mr. Montejo noted a shining small part of this specimen on a place away from the work area, where the unwanted flagstones are accumulated; it was almost covered by the fallen leaves of the rainforest jungle in Chiapas. A desperate search was undertaken to find the counterpart of this specimen; however, the force of rain and the night denied such a possibility.

At first glance, Dr. Alvarado though that this fish was an extinct representative of the seahorses or pipefishes due the armored trunk. He was ready to prepare and describe this fossil when I entered the scene. My involvement in this discovery began in 2016, when I joined the Instituto de Geología of Universidad Nacional Autónoma de México as postdoctoral researcher. The aim of my work is to describe the spiny fishes of different Mexican localities, manly those from the Paleocene outcrops near Palenque City. When I first saw this specimen I immediately identified some characteristics that could resemble a syngnathid, however, by its body shape and configuration of the unpaired fins it seemed more likely to be a  member of the group that includes cornetfishes and trumpetfishes (Superfamily Aulostomoidea). During this study, we began to discover the remarkable features of this fish, some of them never been seen in this group, such as two stout, paired spines on the dorsal and anal fins, few soft rays on fins, and the body and snout covered by rigid star-like scales.

As we went deeper into the study I felt very excited; this was my fist fossil fish described, and it was already revealing itself to be an important clue to understanding the natural history of the aulostomoids, as it extends the fossil record of the group up to the Paleocene. Extant aulostomoids members are easily distinguished from their relatives (i.e., shrimpfishes, pipefishes, and seahorses) by the absence of rigid dermal scutes on the external surface of the body, as well as other features, such as a long body with parallel dorsal and anal fins, and a somewhat deep caudal peduncle. However, our aulostomid fossil was entirely covered with stout scutes. The inclusion the new species Eekaulostomus cuevasae in a morphological phylogenetic analysis, previously proposed by Keivany and Nelson (2006) for extant groups corroborates our hypothesis that this species is the oldest member of the Superfamily Aulostomoidea. This evidence and the comparison of E. cuevasae with other fossil aulostomoid allow us to infer new insights about the evolutionary history of the Superfamily Aulostomoidea.

Eekaulostomus cuevasae, holotype specimen and reconstruction. From Magno and Alvarado-Ortega (2017)

What does this fish tell us about the evolutionary history of Aulostomoidea?

Firstly, the Paleocene age of Eekaulostomus cuevasae represent an increment around 15 Ma on the origin and early diversification of aulostomoids, since the oldest forms were found in the middle Eocene of Europe (Pesciara of Monte Bolca, Italy). Furthermore, its geographical position is the first evidence of the Caribbean origin of aulostomoids with posterior diversification and currently worldwide distribution on tropical seas that still needs to better understood.

Eekaulostomus cuevasae is in the stem-group of aulostomoids. This allow us to say that the loss of dermal scutes, as well as stretching and tapering body, and the increment in the numbers of dorsal and anal soft rays are important morphological changes through the aulostomoid evolutionary history. We believed that these changes are morphological improvements on locomotion, buoyancy and adaptations to peculiar predatory behaviors present on extant aulostomoid species. The living species Aulostomus chinensis, for example, has the strategy to make reverse movements or maintain its body statically on the horizontal position, camouflaging between corals to opportunistically catch the prey.

What was the habitat and lifestyle of these fish? With their unusual heads, what did they feed on?

Unfortunately, little can be inferred about the habitat and lifestyle of this fish. Other fossils from the same locality of Eekaulostomus cuevasae are crabs, coprolites, fragments of turtles, carbonized plants, and a singular fauna of fishes that indicates a marine environment with some freshwater influence; however, more details about the paleoenvironment are still required. For now, what we can say is that E. cuevasae probably was a bad swimming, marine species that lived on marine shallow water, feeding on some crustaceans and small fishes using the peculiar method of prey suction through its feeding apparatus composed by small jaws and extreme elongated snout, like as in living aulostomoids forms.

The scales/scutes if this fish are really bizarre, and don’t look like fish scales at all! How did you recognize what you had? Do any other fish have scales like these?

As I mentioned previously, although living aulostomoid species do not have rigid body coverage, all close relatives have them. Nevertheless, the body coverage on these groups are composed of parallels bony plates that are quite distinct from the star-like scutes present on Eekaulostomuscuevasae. Its generic name is based on the shape of the scutes on this species. The prefix “Eek”, is a Mayan word that means “star” and, together with the word “aulos” (a kind if flute in Greek) and “stoma” (mouth in Latin) composes Eekaulostomus, in reference to a flute mouth fish with star-like scales.

The scutes of Eekaulostomus.

Anything else you’d like to share with us about this fish?

We decided to honor our colleague Dr. Martha Cuevas Garcia naming this fish as Eekaulostomuscuevasae because of her initial impulse that allowed us to perform several of the paleontological projects that are currently developing in Chiapas. Although she is an archaeologist who has spent years of work on different archaeological themes related to the Palenque Maya site, after work together in the paleontological prospection works in the southeastern part of Mexico, now she claims her love for fossils.

Congratulations to the UNAM team on this fantastic discovery of this fantastic fish Eekaulostomus and being chosen as the #1 Open Access Fossil Taxa of 2017!

Reference:

Cantalice KM and Alvarado-Ortega J (2017) Eekaulostomus cuevasae gen. and sp. nov., an ancient armored trumpetfish (Aulostomoidea) from Danian (Paleocene) marine deposits of Belisario Domínguez, Chiapas, southeastern Mexico. Palaeontologia Electronica 19.3.53A: 1-24.
 doi:10.26879/682

Keivany Y and Nelson JS (2006) Interrelationships of Gasterosteiformes (Actinopterygii, Percomorpha). Journal of Ichthyology, 46:S84–S96.

 

Top 10 Open Access Fossil Taxa of 2017: Websteroprion armstrongi | PLOS Paleo Community

This is an article I wrote for the PLOS Paleontology Community blog, and am archiving it here. I was originally published on December 5, 2017. You can see the original post here.

We listened to your feedback from last year’s Top 10 OA Fossil Vertebrates contest, and we agreed. Non-vertebrates needed representation, too! So of the 45 nominees we included in the contest this year, 1/3rd represented various plants, algae, insects, crustaceans, etc.

And as we continue the countdown of the winners of the PLOS Paleontology Top 10 Open Access Fossil Taxa of 2017, I am pleased to feature our first representative of an invertebrate taxon. Coming in at #8 is the fossil bobbit worm Websteroprion armstrongi, from the Devonian Kwataboahegan Formation of Ontario Canada. Described by authors Mats Eriksson, Luke Parry, and Dave Rudkin and published in the Open Access journal Scientific ReportsWebsteroprion represents the oldest bobbit worm (about 400 million years old), and a giant bobbit worm at that!

An artistic reconstruction of Websteroprion amrstrongi attacking an acanthodian fish. Art by James Ormiston.

Now if you are unfamiliar with bobbit worms, then you are in for a terrifying treat. These unusual polychaete worms are still living today and are vicious predators, laying in wait buried in the ocean sediment, their jaws poised like a bear trap, springing to life the minute a hapless fish swims idly by, only to be sucked into the sediment, becoming a meal for an unusual creature. Just watch this video below, courtesy the Smithsonian Channel on Youtube, to see a living bobbit worm in action.

These organisms are mostly soft-bodied, with the exception of their mouthparts, known as scolerodonts. So in the fossil record, often only the scolerodonts are preserved, and they usually aren’t that big. It was the size of the scolerodonts of Websteroprion that caught the eye of the authors. Mats Eriksson, lead author on the study, described to me the discovery of the specimens in the collection of the Royal Ontario Museum (ROM):

“Luke Parry [second author and then a PhD student at the University of Bristol, UK] was doing guest research on full-body polychaete fossils at the ROM back in 2014, and Dave Rudkin [third author on this study and now-retired museum curator at the ROM] showed him the specimens. So, Luke took a quick photograph and sent it to me, knowing that I am an expert on this fossil group.”

Scolerodont fossil impressions of Websteroprion armstrongi. Courtesy Luke Parry Twitter.

Dr. Eriksson continues, “I was quite disappointed when I first laid eyes on the photographs. The state of preservation was far from exceptional and mainly representing negative casts, or imprints, in the rocks. At first I even concluded that it was not worthwhile pursuing since it was ‘just another’ new species without any exciting story to unveil. That is until I asked about the size! Since the original image did not come with a scale bar I had simply assumed that the specimen was of “standard” millimetre size. I did ask Luke, who said that they were in fact pretty big, and provided the scale. That is when I strongly suspected that these must be by far the largest fossil jaws ever reported in the published literature, and a hunch which subsequent research confirmed. Now, this certainly wet my wormy appetite!”

Websteroprion armstrongi CT-scanning reconstructions of scolerodonts in specimen  ROM 63120. Modified from Eriksson et al (2017). CC-BY.

For bobbit worms, these are pretty massive, and for a polychaete worm in the Devonian, even more impressive. With the jaws wide open, they would have spanned about 2 cm across. The body, though not preserved, is estimated by the authors to be over 1 m (3 feet) in length, compared to the body proportions of extant bobbit worms. “I would not say they are necessary bigger than the jaws of extant bobbit worms,” Dr. Eriksson explains to me, “but it was surprising to find such large specimens in 400 million-year-old rocks!”

As Eriksson explains further, “Gigantism in animals is an alluring and ecologically important trait, usually associated with advantages and competitive dominance. It is, however, a poorly understood phenomenon among marine worms and has never before been demonstrated in deep time based on fossil material in this group of animals. The new species demonstrates a unique case of polychaete gigantism in the Palaeozoic, some 400 million years ago.

“Our study also shows that gigantism in jaw-bearing polychaetes was restricted to one particular evolutionary branch within the Eunicida, but has evolved many times in different species in this order of worms. However, while representing an ancient ‘Bobbit worm’ and a case of primordial eunicidan worm gigantism, the specific driving mechanism/s for W. armstrongi to reach such a size remains ambiguous.”

Would Websteroprion have been an ambush predator like its modern-day relatives? “We have little (in fact no) empirical evidence of its diet,” Dr. Eriksson explains. “As we are lacking soft parts we do not have access to preserved gut contents. And there are no coprolites found that can be directly linked to the animal. Inferring the diet of extinct worms (even jaw-bearing ones) is difficult. Especially considering that there are jaw-bearing extant forms that, despite looking like ‘fierce’ carnivorous predators, have proven to have a wide range of feeding habits. With that being said, given its size and compared to its closest modern relatives, I would assume that W. armstrongi had a similar mode of life and feeding habit as the modern bobbit worms. So, perhaps the Devonian fish and cephalopods were not safe from this critter.”

As mentioned previously, Websteroprion specimens caught the eyes of the authors in the collection of the ROM, but were actually collected over 20 years ago.

“The fossil specimens were collected over the course of a few hours in a single day in June 1994, when Derek K. Armstrong of the Ontario Geological Survey was dropped by helicopter to investigate the rocks and fossils at a remote and temporary exposure in Ontario,” Eriksson explains. “Sample materials, from what proved to belong to the Devonian so-called Kwataboahegan Formation, were brought back to the Royal Ontario Museum in Toronto, Canada, where they were stored until they caught the eyes of us authors.”

He adds, “Our study is an excellent example of the importance of looking in remote and unexplored areas for finding new exciting things, but also the importance of scrutinising museum collections for overlooked gems.”

And Websteroprion being a large and possibly terrifying creature wasn’t badass enough, it has a pretty stellar namesake as well. Lead author Mats Eriksson, in addition to being a professor at Lund University, moonlights as a Metal musician, complete with a paleo metal band Primoridal Rigor Mortis. In naming Websteroprion, Eriksson chose to honor a fellow metal musician, Alex Webster, bassist for Cannibal Corpse. And in true Metal fashion, Eriksson recently commissioned an iconic painter for Metal albums, Joe Petagno, to fashion Websteroprion in a dark and fantastical scene worthy of a album cover. The art, which can be seen here, will be part of an upcoming exhibition, Rock Fossils, which will be in Luxembourg in June 2018.

Congratulations to Websteroprion and the team that described it for making the PLOS Paleo Top 10 OA Fossil Taxa of 2017

Reference:

Eriksson ME, Parry LA, Rudkin DM (2017) Earth’s oldest ‘Bobbit worm’ – gigantism in a Devonian eunicidan polychaete. Scientific Reports 7:43061. DOI: 10.1038/srep43061

Source: Top 10 Open Access Fossil Taxa of 2017: Websteroprion armstrongi | PLOS Paleo Community

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Top 10 Open Access Fossil Taxa of 2017: Babelichthys olneyi | PLOS Paleo Community

This unique fish represents the first of its kind in the fossil record, and is named after an infamous sci-fi polyglot!

This is a post a wrote for the PLOS Paleontology Community as part of the Top 10 Open Access Fossil Taxa of 2017. The winners were featured on the PLOS Paleo blog, and I conducted this interview with Donald Davesne, the author of Babelichthys olneyi. This post was published at PLOS Paleo on 11/29/17, and I am archiving it here.

Our readers have spoken, and the Top 10 Open Access Fossil Taxa of 2017 have been selected. To celebrate each individual taxon and study, the editors of PLOS Paleo will highlight each in its own individual blog post, counting down from #10 to the number #1 winner.

Babelichthys olneyi holotype. (A) MNHN.F.EIP11d. (B) counterpart MNHN.F.EIP11g. Scale bars = 20 mm. From Davesne (2017). CC-BY.
At #10, I present Babelichthys olneyi, described and published in the open access journal PeerJ by Donald Davesne, a postdoctoral researcher at the University of Oxford. It is named after the Babelfish from Douglas Adams’ The Hitchhiker’s Guide to the Galaxy, and though this intriguing specimen might not be a polyglot, it still offers up some unique insight into the history of crestfishes.

The opah Lampris guttatis on Faroese stamp FO 546 by Astrid Andreasen. Public domain courtesy of Wikipedia.

Babelichthys, based on a single specimen, was recovered from the Middle-Late Eocene Zagros Basin in Iran. It is the first and only-known fossil unicorn crestfish. Crestfishes, in the family Lophotidae, are deep-sea teleosts that are visually notable by their pronounced cranial crests, hence the name. With only two living species and four extinct species, crestfishes are a small but striking group. You might be more familiar with the closely related oarfishesof the family Regalecidae, which often wash ashore and make for many historic sea serpent tales. Or you might recognize the opah, whose genus name Lampris is the base for the Order Lampriformes despite it bearing zero resemblance to most of the fishes in this order (the opah being round and deep-bodied, and most lampriformes being long and ribbon-like).

Babelichthys clearly resembles other living crestfishes with its pronounced head. But for decades it had mistakenly been identified as a specimen of another crestfish species Protolophotus. It took Dr. Davesne to recognize the unique attributes that set Babelichthys apart from other lophotids and properly designate it as a new species.

Protolophotus holotype, which Babelichthys was originally misidentified as being for several decades. From Davesne (2017). CC-BY.

I was able to ask Dr. Davesne about his work on this fabulous fishy find!

PLOS Paleo: This specimen was collected a long time ago! Why did they go unnoticed as a new taxon for so long? Tell me about your process “discovering” this new species.

The specimen was indeed collected in the 1930s and assigned to another genus, Protolophotus [pictured above]. Another author later recognized that is was distinct and created a new name, but it was invalid because no description was provided. I had noticed the specimen during my Ph.D. at the MNHN in Paris (it was in the public exhibition), but didn’t know about this problem. It wasn’t until my postdoc, during a visit in Moscow to study fossil lampridiforms from Russia that my colleague Alex Bannikov made me realize this taxon needed a new name and a proper description.

The Babelfish is a popular creature in the sci-fi universe. Why did you choose to honor it?

I read the Douglas Adams books a long time ago, and since it is one of the few “fish-related” famous sci-fi references, I had the idea to name a species after it early in my PhD on spiny-rayed fishes. So when I decided to describe and give a name to this very weird-looking animal, I knew it should be Babelichthys!

Closeup of the skull of Babelichthys olneyi. From Davesne (2017). CC-BY
What do you think is the function/purpose of the pronounce crest on the skull of Babelichthys?

Hard to know! The modern relatives of this animal live in the deep water and are almost never observed alive! We don’t know much about their feeding ecology, for example.

This is the first known fossil unicorn crestfish. What does this fossil tell us about the evolution of lophotid fishes?

It shows that this family was already diverse in the early Cenozoic, with relatives to both modern genera now described in the fossil record. More broadly, it helps understanding the timeframe of lampridiform evolution. Our previous research found that the Late Cretaceous ancestors of these animals probably looked like your regular teleost, with a rounded and laterally flattened body. Between the end of the Cretaceous and the middle Eocene, they acquired this series of derived character states that make them so peculiar today, with their very elongate body and weird crests on the head. This suggests that their rate of morphological evolution was quite rapid in the early Cenozoic, but has slowed since then.

 What would have been the habitat or lifestyle of this fish?

Modern crestfishes (and most lampridiforms) live in the mesopelagic environment, between 200 and 1000 m in depth, and spend most of their lives in the water column. We can assume that this was also the case of Babelichthys. Actually, other fossil teleosts found in the same locality in Iran (and also kept in the Paris museum) also belong to taxa that live in this kind of environment today, like hatchetfishes and deep sea cods. It is one of the few potential examples of a mesopelagic fauna that we have in the teleost fossil record.

Do you have any other insight about this organism/discovery that you want to share with the world? Any other thoughts you’d like to add?

I would like to thank you for organizing this contest that showcases open access taxonomic paleo papers. Online open access journals like PeerJ are actually pretty great because they don’t have strict guidelines in term of length or scope, which means that they’re susceptible to accept this kind of very descriptive manuscript that other kinds of journals might deem too ‘boring’. But we still need to publish taxonomical descriptions from time to time, especially in paleoichthyology, where so many awesome specimens are just there in the collections without anyone studying them. I’m also glad that another paper on fossil teleosts won first prize!

Reference:

Davesne D (2017) A fossil unicorn crestfish (Teleostei, Lampridiformes, Lophotidae) from the Eocene of Iran. PeerJ 5:e3381 https://doi.org/10.7717/peerj.3381

Source: Top 10 Open Access Fossil Taxa of 2017: Babelichthys olneyi | PLOS Paleo Community

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Know thy namesake: the story of Gordon W. Weir and fossil fishes

The fossil fish Hemicalypterus weiri was named after Gordon Weir. But who is Gordon Weir?

This Saturday, November 11, the U.S. celebrates Veterans Day, a holiday in which we honor and remember veterans who have served and protected our country (as opposed to Memorial Day, which honors those who specifically died in combat). I have been kicking the idea for this post around in my head for a year now, and the timing seems appropriate to coincide with this year’s Veterans Day.

But, what exactly does paleontology have to do with Veterans Day?

Gibsonlogoblank
Hemicalypterus weiri reconstruction.

Let’s digress for a bit of context. Last year I published a paper in PLOS ONE redescribing an unusual deep-bodied from the Triassic Chinle Formation. The fish, Hemicalypterus weiri is unusual for several reasons, most obvious being its partially scaled body (the anterior half being covered by thick, enameled scales; the posterior half being scaleless, which likely aided in flexibility). Hemicalypterus also possessed unusual teeth that resemble small forks, which were most likely used for a herbivorous feeding behavior, using the multicuspid teeth to scrape algae off of a rocky substrate, similar to modern algae-scraping cichlids. I published a paper in the journal The Science of Nature detailing the multicuspid teeth of Hemicalypterus, and also wrote about it on my blog.

Schaeffer tablecloth copy
Bobb Schaeffer, curator of Fossil Fishes at the AMNH, pictured here with the famous “Woodward Tablecloth” (a story for another day)

Hemicalypterus weiri was originally described by Bobb Schaeffer, the former curator of fossil fishes at the American Museum of Natural History in New York City. His work on the Triassic fishes of the American southwest has been a guiding force in my own career. Schaeffer described several species of fishes from the Chinle, but his description of Hemicalypterus was based on few, incomplete specimens, all of which were lacking articulated jaws and teeth. Schaeffer did not recognize or describe the multicuspid teeth, and it was only as I was preparing newly collected specimens of Hemicalypterus that I found complete jaws on several specimens, displaying the unique tooth morphology that is found in almost exclusively herbivorous fishes in both marine and freshwater habitats.

But Hemicalytperus itself isn’t the point of this post. The point is its specific epithet, Hemicalypterus weiri. As it says in the footnotes of Schaeffer (1967): “For Gordon W. Weir.”

203365_5658200934_o.jpg
A fresh-faced young graduate student perusing Gordon Weir’s geological notes at the U.S.G.S. Field Records collection library.

I had come across Gordon Weir’s name before, several years ago when I was perusing the archives at the U.S. Geological Survey Field Records collection in Denver, Colorado. Looking for more information regarding early fossil collections in the Chinle Formation in Utah, I found all of Gordon Weir’s field notes, government reports, stratigraphic columns, and notes on fossils he had discovered in the region, notably, articulated fossil fishes.

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The handwritten cover on Weir’s report on Fossils from southeastern Utah, amongst reports on uranium deposits. From the USGS Field Collection Records archive.

Weir, along with Y. W. Isachsen (who at the time worked for the Atomic Energy Commission), had discovered fossil fishes while they were surveying southeastern Utah for uranium. As Schaeffer (1967) writes, “It is an interesting comment on the Atomic Age that the search for uranium minerals led to the discovery of abundant and diversified fishes.”

Weir and colleagues reported their findings, as well as some specimens, to the National Museum of Natural History in Washington, D.C.  in 1953. David H. Dunkle, who was curator of fossil fishes at the time, collected additional specimens in 1954, and later brought on Bobb Schaeffer from the AMNH to collect in the region and, ultimately, to describe the fishes recovered from the Triassic deposits.

For Weir’s significant contribution with regard to Triassic stratigraphy, fossil localities, and geology of southeastern Utah, Schaeffer honored Weir with a namesake: Hemicalypterus weiri.

USNM V 23425A_MERGED_0
Holotype of Hemicalypterus weiri.

As I examined new and old specimens of Hemicalypterus weiri for my research, I became  familiar with every aspect of this unassuming little fossil fish: its anatomy, morphology, abundance in the fossil record, localities, etc. Everything but its name. And it felt odd working so intimately on an organism that I did not name; one that already had a name, a name honoring a man I did not know, but to whom I owe a lot.

So when I googled “Gordon W. Weir,” I didn’t expect much. I anticipated some geological papers or reports, and not much else. What I didn’t expect was this:

GWW_nav1
Lt. Gordon W. Weir, WWII Pilot. Circa 1944

As it turns out, Gordon Weir was a lot more than a geologist for the U.S. Geological Survey. Gordon Weir was a decorated World War II veteran, a pilot in the Army Air Corps in the 861st Squadron, 493rd Bomb Group, and 8th Air Force. He served 30 flight missions in Europe in 1944 and 1945.

Weir died in 2011, and according to his obituary, Weir did not discuss his time in the Air Force for decades. His son later found three silver navigator’s medals in the bottom of a drawer and was unaware of much of his father’s war history.

salute.jpg
Gordon Weir, circa 1943, on base in Nebraska.

Thankfully, Weir later became active in the 8th Air Force Historical Society, and has also left a legacy of his time in the War via an online memoir, which I invite everyone to check out, because his time in the Air Force during WWII is absolutely fascinating. He flew in over 30 missions in Europe in 1944 and 1945. When the war ended in 1945, he was training to serve in the Pacific Theatre. In one of his missions in Europe, his plane was one of only two of the twelve planes that returned to England.

steed.jpg
Gordon Weir, circa 1945.

Weir’s memoir documents as much as he was able to recall 50 years after the events, but is laced with photos, documents, anecdotes, humor, and honest insight. He talks about everything from navigating a war-wrecked London, boating on the Cam in Cambridge, and flying in a B-17 bomber into German skies. He talks about the deaths of his friends, and the reality of the war. It’s a candid and fascinating read, and I am glad that it persists on the internet even after his recent passing, just shy what would have been his 89th birthday.

lucky.jpg

After WWII ended in 1945, Weir enrolled in UCLA to study geology, after which came his long career in the U.S.G.S. in which he, as he put it, “[tried] to comprehend the history of the Earth.”

In addition to his work in Utah, Weir also conducted geological research in Kentucky, Arizona, and Indonesia.

His son described him as “intelligent, caring, and interesting.” And I would agree. I am glad that I got to know him a little vicariously through his online memoir. He was truly a fascinating person, and I wish I had met him in person. But it’s truly an honor to be able to work on his namesake, Hemicalypterus weiri.

Read Gordon Weir’s WWII Online Memoir

Gordon Weir’s obituary

References:

Gibson, S.Z. 2016. Redescription and Phylogenetic Placement of †Hemicalypterus weiri Schaeffer, 1967 (Actinopterygii, Neopterygii) from the Triassic Chinle Formation, Southwestern United States: New Insights into Morphology, Ecological Niche, and Phylogeny. PLoS ONE 11(9): e0163657. doi:10.1371/journal.pone.0163657

Gibson, S.Z. 2015. Evidence of a specialized feeding niche in a Late Triassic ray-finned fish: evolution of multidenticulate teeth and benthic scraping in †Hemicalypterus. The Science of Nature — Naturwissenschaften 102:10.

Schaeffer, B. 1967. Late Triassic fishes from the western United States. Bulletin of the American Museum of Natural History 135: 289–342.

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The “Slasher” Ray: An extinct fish with a saw-like nose — PLOS Paleontology Community

Are the “teeth” on a sawfish snout really teeth? A fossil might shed light on the question.

This post was originally written by me and published on the PLOS Paleontology Community Blog on October 30, 2015. The original post can be accessed here.

Happy Halloween everyone! Still looking for a Halloween costume? Instead of dressing as a serial killer with a chainsaw, might I suggest dressing as a sawfish? Maybe not as scary as Leatherface, but just as deadly…if you are a fish.

Click on me! Watch out, "Jaws".... there's a new killer in town
Click on me! Watch out, “Jaws”…. there’s a new killer in town
So, about those teeth along the snout of a sawfish, are they really “teeth”? I have taken the origin of teeth for granted, and it’s a lot more complicated than I thought. A talk I saw in the Fishes Session at the recent Society of Vertebrate Paleontology (SVP) meeting in Dallas, Texas showed me just that, and the talk wasn’t about teeth…exactly. Or was it? That’s what Dr. Charlie Underwood from Birkbeck University, London, is trying to find out, along with colleagues Dr. Zerina Johanson from the Natural History Museum, London and many others (Monique Welton, Brian Metscher, Liam Rasch, Gareth Fraser, Moya Meredith Smith, Alex Riley, Jürgen Kriwet, and Cathrin Pfaff). Underwood’s talk presented an unusual fish from the Late Cretaceous (72–66 million years ago) of Morocco. Called Schizorhiza, it is a relative of extant rays, and had a 1.5-meter-long nose with large, pronounced teeth on the lateral edges, similar to modern-day sawfishes and sawsharks.

Reconstruction of Schizorhiza stromeri, image courtesy of Charlie Underwood.
Reconstruction of Schizorhiza stromeri, image courtesy of Charlie Underwood.
A sawfish (Anoxypristis cuspidata) rostrum from Welten et al. 2015 [2], showing the large, consistently spaced and sized saw-teeth, and their insertion into the rostrum.
A sawfish (Anoxypristis cuspidata) rostrum from Welten et al. 2015 [2], showing the large, consistently spaced and sized saw-teeth, and their insertion into the rostrum.
Okay, before I go any farther (because I had to get this right myself), Sawfish/Sawshark 101: what’s the difference? Sawfish are a family (Pristidae) of rays (Batoidea), characterized by a long snout with pronounced “saw-teeth” on each side of the snout, resembling a saw, hence the name. This description is also true for sawsharks of the family Pristiophoridae, which are true sharks (Selachii). Distinguishing these two groups comes down to more specific details: sawsharks have barbels on their saw and their “saw-teeth” alternate in size between small and large, whereas sawfish have pretty consistent large “saw-teeth” and lack barbels.
Sawfish have their gills on their ventral surface (like rays), whereas sawsharks have gills on the side of their body (like sharks). There are other details, but for brevity’s sake these are some simple ways to tell them apart. They are both cartilaginous fishes but are not closely related to each other, and each independently evolved these really cool (in my opinion), saw-like snouts for the purpose of prey-capture and feeding.
Two species of sawsharks (Pristiophorus nudipinnis a-c and Pristiophorus cirratus d-g) from Welten et al. 2015 [2], showing the barbels and saw-tooth size variation and placement along the snout laterally and ventrall, and along the skull. Two species of sawsharks (Pristiophorus nudipinnis a-c and Pristiophorus cirratus d-g) from Welten et al. 2015 [2], showing the barbels and saw-tooth size variation and placement along the snout laterally and ventrally, and along the skull.
Two species of sawsharks (Pristiophorus nudipinnis a-c and Pristiophorus cirratus d-g) from Welten et al. 2015 [2], showing the barbels and saw-tooth size variation and placement along the snout laterally and ventrally, and along the skull.

Now that you have those two groups down, let’s add a third, the Sclerorhynchoidea. These are Mesozoic forms that include Schizorhiza, and are closely related to rays. As I mentioned before, sclerorhynchids like Schizorhiza also have elongated snouts with “saw-teeth.” They are a wholly extinct group, present in the Cretaceous and Paleogene in epicontinental seas.

In fact, the rostrum saw evolved at least 5 times in different groups of sharks and rays [2]. But what do sawfishes, sawsharks, and Schizorhiza have to do with actual teeth?

Ever had the chance to touch a shark or ray?  They’re skin is not scaleless, but covered in minute, hook-shaped denticles (placoid scales). If you brush your hand away from the head, the skin feels smooth, but if you reverse and brush towards the head, your skin will catch on these tiny hooks, like velcro. The internal structure and composition of these hooks is not dissimilar to that of teeth, and it has been long hypothesized that in the earliest jawed vertebrates these denticles migrated into the jaw region, and eventually evolved into oral dentition. I was taught this “outside in” hypothesis, that teeth are a specialized, derived form of those dermal denticles that cover the skin of sharks, rays, and other cartilaginous fishes. But this hypothesis has been called into question by several researchers, including Underwood and his colleagues. They have published a series of papers (linked below) that have been testing and comparing how teeth develop during ontogeny, and how that compares to they way dermal denticles and “saw-teeth” develop.

So far, the team has examined the morphology of teeth and denticles and several cartilaginous fishes, as well as the genetic controls that dictate the order and development of oral dentition, and they have determined that dermal denticles and oral dentition may not have the same evolutionary origin. Chondrichthyans are polyphyodonts, meaning that their teeth are

Examples of unusual batoid jaws from Underwood et al. 2015 [1], showing clear morphological differences. The batteries of teeth rotate from inside the mouth to outside as the rays age.
Examples of unusual batoid jaws from Underwood et al. 2015 [1], showing clear morphological differences. The batteries of teeth rotate from inside the mouth to outside as the rays age.

continuously replaced in a “many-for-one” style of replacement, and sharks and rays are noted for their batteries of teeth, which develop lingually and move to the functional surface (i.e., the mouth margin for munching on prey) and, if not lost, will continue to rotate outside of the functional surface. Batoids also often display a variety of unusual morphologies to exploit different food sources [1].

In contrast, denticles do not follow this ordered pattern of replacement seen in the dentition. Rather, denticles develop as space becomes available (i.e., as the organism grows), and are only replaced as denticles are lost, in contrast to chondrichthyan teeth that grow regardless if its predecessor is lost or not.

So, does “saw-tooth” development resemble what is observed in dermal denticles or oral dentition? Welten et al. [2] examined this and noted two differences between sawfishes, sawsharks, and sclerorhynchids. Sawsharks and sclerorhynchids share a similar pattern, despite not being closely related: the saw-teeth develop under the skin of the embryo before “swinging” laterally into place along the rostrum, and are only replaced when the predecessor is lost. In sawfish, however, the prominent saw teeth fit into sockets within the rostrum and grow continuously. If a saw-tooth is lost, it is not replaced (bad luck, sawfish). The development of saw-teeth is associated with rostrum growth, and replacement is space-dependent, thus “saw-teeth” aren’t teeth, at least in the classical sense, and are more comparable to dermal denticles.

We’re back to Schizorhiza, the unusual ray from the Cretaceous of Morocco that was the subject of Underwood’s talk at SVP.

When I asked Underwood about collecting specimens of Schizorhiza, he told me, “The specimens all came from the phosphate mining area near Khouribga, Morocco. In this area sedimentary phosphorites form a unit about 10 meters thick but representing maybe 15–20 million years from latest Cretaceous to Early Eocene. The whole rock, including fossils, is ground up to make fertilizer, but locals, mostly the quarry workers, try to collect larger fossils as they emerge, especially mosasaurs in the Cretaceous and crocodiles, turtles, and large sharks in the Paleocene and Eocene. In the process, some rare specimens are collected, such as pterosaurs, birds, land mammals and Schizorhiza. These fossils are purchased by local wholesalers who prepare the fossils and sell them on to museums and collectors. Whilst a lot can be said against commercial trade in fossils, this is really a rescue operation, and it only happens because there is a market for the fossils.”

Mosasaur fossils in a warehouse in Morocco, still in their plaster jackets.
Mosasaur fossils in a warehouse in Morocco, still in their plaster jackets.
Schizorhiza fossils provide a high amount of developmental data, which is unusual for a fossil and beneficial for testing the relationship (or lack thereof) between the development of teeth, dermal denticles, and saw-teeth.

A complete rostrum from Cretaceous Schizorhiza stromeri (specimen NHMUK PV P.73625), with close-up images of the alternating saw-teeth and their deeply lobed roots. From Smith et al. 2015 supplement [3]
A complete rostrum from Cretaceous Schizorhiza stromeri (specimen NHMUK PV P.73625), with close-up images of the alternating saw-teeth and their deeply lobed roots. From Smith et al. 2015 supplement [3]

Multiple specimens were examined via volume-rendered and segmented micro-CT scans and histological thin sections. The saw-teeth of Schizorhiza differ from what is observed in sawfish and sawsharks; the saw-teeth form a continuous battery of staggered structures to create a functional saw-edge, with smaller teeth nearer the far end of the snout but not reaching the very tip of the rostrum. Each tooth has a small crown and a root with four deep lobes that would have extended into cartilage along the rostrum edge. New saw-teeth develop internally at the rostrum edge and point towards the skull, and as they develop they rotate laterally and finally end up in below older teeth, within the root space left by the older teeth. These teeth would then remain there waiting to replace their predecessor, a process that is more common in bony fishes but otherwise unknown in chondrichthyans.

Micro-CT scans of the rostrum of Schizorhiza stromeri (specimen NHMUK PV P. 73626), color coded to show the difference in different ages of files of teeth.
Micro-CT scans of the rostrum of Schizorhiza stromeri (specimen NHMUK PV P. 73626), color coded to show the difference in different ages of files of teeth, and showing in (a) that new teeth point caudally (green), rotate laterally (purple), and then point outward (red). (d and f) show how newer teeth reside in the root cavity of older teeth. From Smith et al. [3]
The origin of development of rostrum saw-teeth appears to begin at the symphyseal (center) tip of the rostrum, which is similar to the way that the oral dentition develops in sharks and rays. Schizorhizacreates a bit of a paradigm, with saw-tooth development that resembles the way teeth develop in sharks and rays, though the study concluded that the method of development is merely convergent, and that the saw-teeth in Schizorhiza are modified skin denticles, as what is shown in sawfishes and sawsharks.

Schizorhiza provides a great example of why scientists should continuously question and test ideas that are long taken for granted. The specimens are absolutely stunning and allow Underwood, Johanson, and their team to demonstrate that the origin of saw-teeth, oral teeth, and dermal denticles in sharks and rays, don’t represent as “cut and dry” a story as we all have assumed. Read their papers below and follow along as they continue to research the mystery of the “saw-slashing” fishes.

References:
[1] Underwood CJ, Johanson Z, Welten M, Metscher B, Rasch LJ, Fraser GJ, Smith MM (2015) Development and Evolution of Dentition Pattern and Tooth Order in the Skates and Rays (Batoidea; Chondrichthyes). PLoS ONE 10(4): e0122553. doi:10.1361/journal.pone.0122553

[2] Welten M, Smith MM, Underwood C, Johanson Z. (2015) Evolutionary Origins and Development of Saw-Teeth on the Sawfish and Sawshark Rostrum (Elasmobranchii; Chondrichthyes) Royal Society Open Science 2: 150189. doi:http://dx.doi.org/10.1098/rsos.150189

[3] Smith MM, Riley A, Fraser GJ, Underwood C, Welten M, Kriwet J Pfaff C, Johanson Z. (2015) Early Development of Rostrum Saw-Teeth in a fossil ray tests classical theories of the evolution of vertebrate dentitions. Proceedings of the Royal Society B 282: 20156128. http://dx.doi.org/10.1098/rspb.2015.1628

Source: The “Slasher” Ray: An extinct fish with a saw-like nose | PLOS Paleo Community

 

Laser-Stimulated Fluorescence in Paleontology — PLOS Paleo Community

A new technique can be used to examine even the tiniest of details on fossils.

This is a blog post I wrote for the PLOS Paleo Community on October 4, 2015 and am archiving here on my website.  The original post can be accessed here.

On Wednesday, October 7, 2015, PLOS Paleo hosted a redditscience ‘Ask Me Anything’ on  laser-stimulated fluorescence (LSF) in paleontology. [Here’s a link to the completed AMA.]

Our featured paleontologist for this AMA was PLOS author Thomas Kaye, a Research Associate at the Burke Museum in Seattle, Washington. Kaye and co-authors (Amanda R. Falk, Michael Pittman, Paul C. Sereno, the late Larry D. Martin, David A. Burnham, Enpu Gong, Xing Xu, and Yinan Wang) have developed a pretty impressive, non-invasive technique to examine fossils in ways we might not have really considered, using equipment that is readily accessible to any paleontologist. Let’s discuss…

For decades paleontologists have used and manipulated different modes of lighting to examine fossils. Something as simple as moving a flexible arm lamp so that it casts light across a specimen laterally rather that directly down upon it can make surface features of a fossil “pop” — and pretty common when, like me, you work on flattened specimens like fish fossils and are desperate for some surface topography. Paleontologists also use fluorescence to examine specimens by casting UV light upon a fossil, causing some minerals, such as hydroxyapatite or fluorite, to absorb UV wavelengths and emit light in a different wavelength. This produces those lovely bright colors that make the fluorescing fossil stand out from the darker rock matrix, and thus allowing the scientist to recognize morphological characters that are otherwise unseen in normal light with little contrast against the matrix.

Still these traditional methods are limited for some specimens, particularly if you have fossils that don’t fluoresce under standard UV light or your are trying to examine soft-tissues or details that are fairly close in color to the matrix or obscured by matrix. Kaye et al.’s paper describes a next-generation technique using stronger laser tools to look for characteristics in a fossils that would have otherwise remained unseen using older techniques. As for the specifics of LSF, I am not an expert and I urge you to read the paper yourself, but let’s talk about some of the great case studies that this paper provided, giving paleontologists and paleoanthropologists all kinds ideas for using LSF.

An unidentifiable specimen from a Liaoning rock slab containing a Microraptor specimen.
An unidentifiable specimen from a Liaoning rock slab containing a Microraptor specimen.

I spoke with one of the paper’s co-authors, David Burnham, the Fossil Preparation Lab Manager at the University of Kansas (KU), and he gave me a little backstory about his involvement with LSF. He and Larry Martin, the late Curator of Vertebrate Paleontology at KU, had found a mystery fossil on a slab containing a Microraptor, but the visible bones were small and identification proved difficult.

Martin had known Kaye and the techniques he had been developing, so they sent the slab to Kaye to analyze, and using this newly-developed LSF technique, they were able to identify the specimen as a fish, and even were able to recognize teeth, scales, and other bones that would have remained invisible to Martin and Burnham without the use of lasers.

Specimen under (A) White light photo and (B) fluorescence with a 457 nm blue laser. LSF showed fish teeth (indicated by arrows), bones, and scales nearly invisible under white light.
Specimen under (A) White light photo and (B) fluorescence with a 457 nm blue laser. LSF showed fish teeth (indicated by arrows), bones, and scales nearly invisible under white light.

Likewise, Amanda Falk, a Visiting Assistant Professor of Biology at Centre College in Danville, Kentucky and co-author on the paper, needed a better way to decipher primitive bird plumage on a fossil and began working with Kaye. Other techniques, such as scanning electron microscopy (SEM) really only detail surface topography, and to better see the barbs and barbules of the feather, Kaye and Falk use LSF in a different way by shining the laser on the fluorescent carbonaceous matrix, thus ‘backlighting’ the feathers.

Feather structure comparison using white light (A), polarized (B) and laser illumination (C), showing how LSF provides a silhouette of the feather barbules by backlighting the specimen.
Feather structure comparison using white light (A), polarized (B) and laser illumination (C), showing how LSF provides a silhouette of the feather barbules by backlighting the specimen.
“I think it [LSF] has excellent utility in a variety of lab situations,” Burnham said, “I have used the laser on rock samples as well with very good luck. The laser illuminated the volcanic constituents in the sediment really well so it was helpful to illustrate the amount of that material and how it was distributed in the rock.” LSF can also be used to sort microfossils, and this technique is laid out wonderfully in the paper. Kaye and co-authors were even able to automate the process with success.

A mid-Holocene-aged Gobero skeleton of a small girl preserved wearing an arm bracelet.
A mid-Holocene-aged Gobero skeleton of a small girl preserved wearing an arm bracelet

LSF is not limited to geochemical and paleontological studies. Paleoanthropoligsts can take advantage of the LSF technique to examine sensitive specimens. The Kaye et al. paper outlines a case where a mid-Holocene female skeleton had a bracelet around her upper arm, but removing the bracelet was impossible without destruction to the skeleton.

A laser was scanned over the artifact, and revealed details that allowed the scientists to determine that the bracelet was made from a hippopotamus tusk.

Bracelet under normal light (A), and fluorescing under a hand-scanned laser (B). The cracking pattern in the upper left corner is only visible under fluorescence and aided in the identification of the bracelet material as hippopotamus tooth.
Bracelet under normal light (A), and fluorescing under a hand-scanned laser (B). The cracking pattern in the upper left corner is only visible under fluorescence and aided in the identification of the bracelet material as hippopotamus tooth.

Interested in this technique for your own specimens? Lucky for you, the equipment and lasers are relatively inexpensive and available. A cheap, everyday laser pointer won’t cut it, though. “We found that the power of the laser was important, so everyday laser pointers were not enough,” Burnham told me.

“I used [a] 400 mW laser pointer,” Falk added, “The trouble with the laser pointer is that it can only be used for about five minutes before you need to turn it off and cool it down. If you want continuous use of the laser then you need a lab-grade laser. We bought a 300 mw one, which [cost] about $500 and not that bad. These are really affordable…in short you can get a working [LSF] system in your lab for less than a thousand dollars. The more powerful the laser, the brighter the fluorescence. Just remember to buy eye protection, too!”

Burnham echoed his sentiment about lab safety, “…One should use caution as the lasers can damage your eyes, and correct protection (safety glasses matched to laser type) must be used. I think the only other drawback is getting the specimen in a room with no light.”

Source: Laser-Stimulated Fluorescence in Paleontology | PLOS Paleo Community

Oldest direct evidence of humans in the Americas? — PLOS Paleo Community

A discovery in an underwater cave in Mexico may indicates the earliest human settlers of the Americas.

This is a blog post I wrote for the PLOS Paleo Community on August 30, 2017. The original post can be accessed here.

Featured Image Credit: Nick Poole and Thomas Spamberg, Liquid Junge Lab. CC-BY.

When did humans really arrive in the Americas? It has been a subject of a lot of debate by archaeologists and paleoanthropologists, For decades, it was generally accepted by most that around 13,000 years ago, the Bering Strait opened up enough (as in, became ice-free) for humans to traverse across from Asia into North America before spreading southwards. But as more and more pre-Clovis archaeological remains were discovered, paleoanthropologists came to a consensus that human arrival in the Americas could have been as early as 22,000 years ago. A more recent study published earlier this year in Nature gave a new oldest estimate that is 100,000 years older than all previous estimates placing human presence in the Americas, but is based solely on markings on mastodon bones and not on actual human bones. Critics of that study suggest that the markings cannot be definitively attributed to humans and could have been made naturally by rocks or other erosional processes.

Regardless, the oldest claims for humans in the Americas is based on tools, artifacts, scraps, and very little is based on osteological remains. When bones are found, they are often very fragmentary. A new paper, published today in PLOS ONE by Stinnesbeck et al., discusses some well-preserved human remains that were discovered in a submerged cave system in the Tulum area of southern Mexico.

The remains were first brought to the attention of the researchers in 2012 through social media. From the photographs of the site, it was clear that about 80% of the skeleton remained intact and partially articulated, including a skull and limbs. Unfortunately, about a month after first publicized on social media, the site was vandalized, and most of the bones were stolen, leaving only about 10% of the skeleton, mostly scrappy parts that were inaccessible to the vandals.

A) The skeleton in situ prior to its theft and vandalism; B and C) photographs showing bones before and after the theft, the orange arrow indicates the stalagmite growing out of the pelvis used for dating the skeleton. From Stinnesbeck et al. (2017). CC-BY.

The researchers were able to reconstruct the position of the skeleton based on interpretation of the photos. And visiting the site, they were able to collect many bones and bone fragments. Of particular note is a part of the pelvis that was firmly attached to the substrate due to the growth of a stalagmite.

It was this stalagmite that became important in dating this skeleton. Other human remains have been discovered previously in Tulum, and were carbon-dated to about 10,976±20 y BP to 11,670±60 y BP. However, this new study suggests that the bioapatite used for previous studies should be used with caution, as it is susceptible to contamination.

Different views of the Chan Hol II pelvis within the CH-7 stalagmite. Arrow in Fig A points to the CH-7 stalagmite prior to the robbery of the skeleton. From Stinnesbeck et al. (2017). CC-BY.

Instead, Stinnesbeck et al. (2017) used U-series techniques to date the skeleton. The U/Th samples were taken from the stalagmite that was growing through the pelvic bone, with samples taken adjacent to the bone both above and below. Using mass spectrometry, the data indicates that the skeleton from the Chan Hol underwater cave is approximately 13,000 years old, thus representing one of the oldest ages of a human present in the Americas, based on definitive direct osteological evidence.

At the time during the Late Pleistocene, this cave would have been dry and accessible, with the sea level more than 100 meters below its current level. This skeleton, along with other remains found in the Chan Hol cave system, could represent an early human settlement along the sea. The karst labyrinth of caves were later flooded, thus preserving the archaeological and paleoanthropoligcal remains inside.

Though it is unfortunate that the site was looted, the results of this study based on what was left behind give clear evidence and possibly a new understanding of the earliest settlements in Mesoamerica.

Reference:

Stinnesbeck W, Becker J, Hering F, Frey E, González AG, Fohlmeister J, et al. (2017) The earliest settlers of Mesoamerica date back to the late Pleistocene. PLoS ONE 12(8): e0183345. https://doi.org/10.1371/journal.pone.0183345