Mesozoic Monthly: Aspidorhynchus

As we all seek out responsible ways to enjoy our summer months while the world continues to respond to COVID-19, many of us are embracing the therapeutic effects of the great outdoors. One popular activity, especially in and around the Three Rivers, is fishing. Some modern fishes look positively primeval, as if they were hooked straight out of the Age of Dinosaurs and reeled into the present day. For July’s edition of Mesozoic Monthly, our star is Aspidorhynchus, one of the weird and wonderful fishes that inhabited the oceans of the Mesozoic Era.

Let’s start with a quick lesson on fish, for context. There are two main groups of bony fishes. One group, the class Sarcopterygii, are called the lobe-finned fishes because they have fleshy, limb-like fins that they use to paddle through the water like oars. The first vertebrates to go on land were sarcopterygians, and the descendants of these adventurous fish eventually evolved into amphibians, reptiles, and mammals – including us! Despite their prolific limbed descendants, sarcopterygians make up only a small fraction of fishes today. The vast majority of fish belong to the other class: Actinopterygii, or the ray-finned fishes. These fishes have delicate ray-like bones supporting thinly webbed fins instead of the meaty fins of the sarcopterygians. Actinopterygians are so successful that they dominate both freshwater and saltwater ecosystems, thrive in a variety of habitats, and fill various ecological niches. Such diverse lifestyles mean that actinopterygians come in many shapes and sizes. Nemo (a clownfish) is an actinopterygian. So is the barracuda that ate his mother, the catfish in the Monongahela River, and the unfortunate goldfish you won at the carnival as a kid. Most fossil fishes, like Aspidorhynchus for example, are also actinopterygians.

Aspidorhynchus is an extinct member of the order Holostei, nested, in diagrams of relatedness, within the class Actinopterygii. The only members of the Holostei today are gars and bowfins. Superficially, Aspidorhynchus looks like a gar, but it is more closely related to bowfins. Its name means “shield snout,” in reference to its pointy, swordfish-like upper jaw. Unlike swordfish, which lack teeth as adults, this snout was filled with many sharp teeth. The limited flexibility of its skull restricted its diet to tiny fish, two inches (5 centimeters) in diameter at the largest. Aspidorhynchus was not very large itself, its slender body only growing to approximately two feet (60 centimeters) in length. It was covered with ganoid scales, which are hard, diamond-shaped scales made with a shiny compound called ganoin. Only a few types of modern fishes have ganoid scales, including gar, sturgeon, and paddlefish.

Jurassic feeding frenzy: the pterosaur (flying reptile) Rhamphorhynchus and the predatory fish Aspidorhynchus attack a school of smaller fish. Usually, the baitfish were the only casualties here, but once in a while, everybody lost (see below!). Art by RavePaleoArt on DeviantArt, reproduced with permission.

Although species of Aspidorhynchus lived in the Jurassic and Cretaceous periods, we know that it encountered the same struggles as some modern fish due to several remarkable fossils. Just like swordfish, the pointy snout of Aspidorhynchus frequently got it into trouble by impaling other animals! The abundance of fossil evidence for this was provided by the unique conditions of the habitat preserved in the famous Solnhofen Limestone of Germany. In the Late Jurassic, this area was an isolated series of lagoons that accumulated a bottom layer of anoxic brine, which is extra-salty, low-oxygen water where oxygen-dependent (aerobic) life cannot survive. Despite this, the surface still teemed with life: fishes and marine reptiles dominated the water, small non-avian dinosaurs scurried along the shore, and pterosaurs (flying reptiles) and archaic birds flew overhead. The fish-eating pterosaur Rhamphorhynchus seems to have been a fairly frequent victim of the snout of Aspidorhynchus, with multiple fossils documenting unfortunate collisions in which the fish’s snout pierced and became entangled in the wing membrane of the pterosaur. (For a summary of pterosaur wings, check out the March edition of Mesozoic Monthly, on Nemicolopterus.) It’s obvious from the size of the animals that neither was trying to eat the other, but somehow, they became stuck together. As the two animals struggled to survive, they slowly drifted downward into the anoxic brine, where they suffocated and settled onto the bottom of the lagoon. If any other animals had tried to eat or otherwise disturb the corpses, they would have died in the brine as well, so the fossils of the Solnhofen Limestone are typically pristine and undisturbed by scavengers.

Three views of the most famous (and probably the most beautiful) Aspidorhynchus vs. Rhamphorhynchus fossil from the Upper Jurassic Solnhofen Limestone of southern Germany. Avid fisherman Matt Lamanna, the head of Vertebrate Paleontology at Carnegie Museum of Natural History (CMNH), jokes that the Aspidorhynchus looks angry, as if it’s mad about getting its snout stuck in the Rhamphorhynchus and dooming them both. Sorry Matt, this is just a quirk of preservation – the compression of the Aspidorhynchus skull during fossilization gave it the appearance of having grouchy eyebrows that weren’t there in life. You can learn more about this specimen in a paper by Frey and Tischlinger (2012). And if you want to see real fossils of both of these animals in person (albeit preserved separately), come visit the Solnhofen case in CMNH’s Dinosaurs in Their Time exhibition.

Because Aspidorhynchus lived only during the Mesozoic, there’s no chance that a modern-day angler will ever hook one. But should you find yourself fishing in one of Pennsylvania’s rivers or lakes this summer, and manage to land a gar or bowfin, pause for a moment and reflect on the ancient legacy of these fishes – a heritage that dates to the Age of Dinosaurs.

Lindsay Kastroll is a volunteer and paleontology student working in the Section of Vertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

2 March 2019 Carnegie Museum of Natural History and Art (7)

@carnegiemuseumnaturalhistory

Fred the Crystal Skull

by Debra Wilson

Just about every year since the Carnegie Museum of Natural History acquired it, Fred the Crystal Skull has made an appearance in Hillman Hall of Minerals and Gems right around Halloween. So how did we acquire a crystal skull and how did it get the name Fred you ask? Just to set the record straight right off the bat, Fred is not one of the dozen or so mysterious skulls that some think were carved by an ancient Mesoamerican civilization thousands of years ago. Our skull was carved and polished from a single quartz crystal with modern tools in Brazil and was donated to the museum in 2004 by South American Gems, Ltd located in Guarapari, Espirito Santo, Brazil.Germany, China and Brazil currently produce thousands of carved crystal skulls every year in numerous sizes. Fred measures 7.8 inches high by 5 inches wide, which is slightly smaller than the average human skull (8 to 9 inches high and 6 to 7 inches wide) so he was named after a man of small stature, namely the step father of the former Head of the Section of Minerals Marc Wilson. Marc was Section Head from August 1992 to August 2017.

As you can see in the photograph of Fred, he has some internal flaws and fractures which is very common in the mineral quartz. Chemical impurities, physical flaws and twinning in natural quartz are issues that caused industry to develop a commercial process of manufacturing pure, electronics-grade quartz that can be used in circuits for consumer products such as televisions, radios, computers, cell phones and electronic games, just to name a few, and for crystal-controlled clocks and watches. As it so happens, the Section of Minerals also has a few lab-grown quartz crystals in the collection, including a large crystal nicknamed The Football that is nearly a foot across.

You will notice it is so clear that you can see the growth patterns of the bottom surface through the crystal. The Football was part of a donation of 57 lab created specimens given to the Section of Minerals in 2017 by Lynn Boatner just before he retired from Oak Ridge National Laboratory in Tennessee.

Fred will be on display in front of Wertz Gallery on October 24.

Debra Wilson is the Collection Manager for the Section of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Happy Ctenophore Day!

by Tim Pearce

Ctenophore, Mertensia ovum

Most people have heard of 6 to 10 of the 30 modern animal phyla. (A phylum is a major group of animals). In fact, most of us have (intentionally) eaten at least 3 phyla: Chordata (including vertebrates), Arthropoda (including shrimp), and Mollusca (including clams and snails). The adventurous among us might have (intentionally) eaten three additional phyla: Annelida (including earthworms), Cnidaria (including jellyfish), and Echinodermata (including sea urchin [as roe] and sea cucumbers). Beyond those 6 phyla, some of us might have heard of parasitic or pest organisms such as Nematoda (round worms) and Platyhelminthes (flat worms), or other interesting phyla such as Porifera (sponges) and Tardigrada (water bears), but most phyla are unknown to most people.

Behold the phylum Ctenophora or comb jellies, which live in ocean water around the world. Their jelly bodies somewhat resemble jellyfish but ctenophores lack stinging cells. They have 8 rows of cilia that look like combs, hence the name (ctene means comb and phora means bearing). Their two longer, retractable tentacles are fringed with smaller tentacles covered with sticky cells that capture prey. Ctenophores range in size from as small as a millimeter (1/25 inch), through the 1-3 cm (0.6-1.25 inch) typical ovoid forms, to the 1.5 meter (5 foot) long belt-like forms known as the Venus girdle.

Ctenophore, Bolinopsis infundibulum

The “C” in ctenophore is silent, so when pronounced, the name sounds like 10 oh 4, which in the United States date system corresponds to October 4th. Consequently, October 4th is Ctenophore Day!

How to celebrate? Tasty fare could include gooseberries and walnuts, given that common names for ctenophores include sea gooseberry and sea walnut. Kiwi fruits are known as Chinese gooseberries (even though they are neither from China nor are they gooseberries), and they are in season in North America in October, so you could enjoy some kiwi fruit this Ctenophore Day!

Timothy A. Pearce, PhD, is the head of the mollusks section at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Other dinosaur draws at the Carnegie Museum of Natural History in Pittsburgh, PA.  The T. rexes are fantastic, but their entire collection is extraordinary!

Texas Solar

By Patrick McShea

Within We Are Nature an interactive kiosk known as EarthTime documents alarming change over recent decades in glacial melting, the clearing of rainforests, and coral bleaching. The imagery, which was generated by NASA satellites and compiled by students at Carnegie Mellon University, is simultaneously displayed on a table-mounted touchscreen and a towering adjacent display screen.  

Literal glimmers of hope appear on both screens when visitors select the digital loop that documents the increase in the installation of solar energy panels across the US between 1984 and 2016. A textbox message directs viewers to, “Notice how installations start on the coasts and make their way inland.”

A recent visitor who replayed the seven-second simulation a few times voiced her state-focused perspective to a companion: “Watch this. Solar energy blooms in Austin before it does in Houston or Dallas.”

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

(photo by Josh Franzos)

Although appearing in all the Jurassic Park films, this T. rex isn’t a copy. In fact, this specimen is significant because it is the exact opposite—a holotype of the species. A holotype is a specimen upon which a given species is based. In other words, Carnegie Museum of Natural History’s T. rex is the “gold standard” to which all potential fossils of this notorious meat-eater must forever be compared. Contrary to the movie titles, T. rex roamed the western United States and southwestern Canada during the late Cretaceous Period. 

For more insights like these, attend our Jurassic Park After Dark event and watch Jurassic Park with our dinosaur expert. You will even be able to pick his brain about the likelihood of Jurassic Park becoming a reality.

To purchase tickets, visit https://carnegiemnh.org/visitor/things-to-do/after-dark/

The original T-Rex!

Clues

By Amy Henrici

Collection Managers often solve fossil mysteries, and sometimes we have only a few clues to assist us. A recent mystery involved some rib fragments prepared by PaleoLab volunteers. Individual packages containing rib fragments found in an old cardboard box stashed in a Vertebrate Paleontology storage room proved to be perfect for PaleoLab volunteers to hone their preparation skills.

My task as Collection Manager is to catalog and integrate these ribs into the fossil mammal collection. Fortunately, most of the rib packages contained field labels, which are used to record information when the specimen is collected. My first clue came from the Description category of a field label with one of the rib packages, and it indicated that the rib connected with a block (which consists of fossil and rock). Because there are no blocks of unprepared fossil mammals in storage, I had to assume that this block had been prepared and the specimen was cataloged. The field label lacked a catalog number (Department No. on the label) and any locality information, which would normally assist in locating the rest of the specimen.

This field label must have been printed for an expedition to Brazil, and the left overs were used by all museum expeditions until they ran out.

The only clue that I had to link the rib to a cataloged specimen in the Section’s computerized database was the block number (Blk. 11/1931), which are entered in the field number category of the database. A search of the database retrieved two specimens with this field number, CM 6425 and CM 36355. Both were brontotheres, formerly known as titanotheres, which are large, extinct rhinoceros-like herbivores. I located the specimens in the collections, and both included incomplete ribs. The field label shown here mentioned that the rib made contact with a “…portion in block indicated by letter D”. Amazingly, I found the letter D written on the broken end of a rib cataloged as CM 6425, and the rib fragment associated with the field label connects to it. I was able to fit all of the rib pieces prepared in PaleoLab onto other ribs cataloged as CM 6425.

The rib piece held in the left hand fits onto a piece stored in this drawer. Both have the letter D written on them at the point where they join. (Photograph taken by Norm Wuerthele)

Archive image showing the skeleton of the brontothere, Brontops dispar, CM 767, which can be seen on exhibit in Cenozoic Hall.

Amy Henrici is the Collection Manager for Vertebrate Paleontology at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences of working at the museum.

About 130,000 unique and rare fossils from western Europe were purchased by Andrew Carnegie in 1903 from Baron de Bayet, executive secretary to King Leopold II (at turn of last century) Belgium. 

Examples of fossils on exhibit in our core exhibition Dinosaurs in Their Time are from Lyme Regis (England), Holzmaden (Germany), and Solnhofen (Germany). 

The fossils were collected from famous paleontology sites in Europe and United States more than a century ago.

(Not So) Boring Clams

by Tim Pearce

Some clams, in the families Teredinidae and Pholadidae, bore holes in wood or rock that is immersed in seawater. We humans often think of wood and stone structures as relatively permanent, but these clams force us to challenge that idea. In fact, the wood-boring clams, known as ship worms, are a centuries-old scourge to shipping activities because they weaken wooden ships and pilings.

Wood bored by shipworm, Lyrodus pedicellatus

The wood-boring clams are highly modified from the clams that normally come to mind. Their shells are reduced to a pair of abrasive cutting tools at the end of a long, worm-like body. The clam twists the shells back and forth, breaking off chunks of wood as it burrows through the wood. The clam eats the wood, aided by symbiotic bacteria that digest the wood. As the clams burrow, they somehow seem to know when they are near another clam’s tunnel and they avoid breaking into it, but how they know is a puzzle.

Rock bored by clam, Penitella penita, from Washington State

Human efforts to prevent shipworms from destroying wooden ships and pilings included coatings containing tributyl tin (TBT). While paints containing TBT did protect against shipworm damage, the chemical was toxic and caused reproductive problems in aquatic organisms. In particular, TBT causes masculinization of female fish, snails, and other aquatic species. So, other methods to protect wood are now used instead.

Rock-boring clams also have shells adapted for abrasion at one end, but they differ from the ship worms because the shells of the rock-boring clams are not as reduced as in the ship worms, and the rock boring clams do not derive nutrition from the rock particles. As the clams bore into the rock, they grow, so the burrow tapers wider inward, so the clam shell cannot get out. However, the clam gains great protection from predators. The clam siphons protrude through the rock opening to bring in water and food and to expel wastes.

Rock-boring clam, Zirfaea crispata, from England

Other clams specialize in boring in calcium carbonate. These clams are important in the destruction of limestone, reefs made of coral skeletons, and even shells of other mollusks.

Timothy Pearce is the Head of the Section of Mollusks at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

Anzu wyliei

Perhaps better known by its colorful nickname, the “Chicken from Hell,” Anzu wyliei is a bird-like oviraptorosaurian dinosaur. More specifically, it is a member of the Caenagnathidae, a poorly understood group of oviraptorosaurs that lived mainly in North America during the Cretaceous Period. Anzu has distinctive characteristics that are not found in any other dinosaur, plus other typically oviraptorosaurian features such as a crested skull and a toothless beak. It grew to a length of at least nine feet and had a relatively short tail and long, spindly legs with three-toed feet. Its long arms featured sharp, hooked claws that may been used to catch prey or for protection.

With a name that translates to “Wylie’s feathered demon,” this dinosaur presents numerous riddles to scientists. Due to the shape of its toothless jaws, it is unknown if Anzu was a carnivore, like most other theropod dinosaurs, or if it was a plant eater. Anzu may even have been an omnivore, eating both plants and small animals.

Carnegie Museum of Natural History’s two skeletons of Anzu are the most complete oviraptorosaur specimens yet found in the Western Hemisphere. Museum scientists and their collaborators are continuing to study the dinosaur’s bones to gain a better understanding of the species. Because the real fossils are extremely fragile, more so than those of most other dinosaurs on display, the skeleton on exhibit is a cast. It is a combination of replicas of the museum’s two real specimens, which were discovered in the late 1990s in ~66 million-year-old rocks belonging to the Hell Creek Formation in Harding County, South Dakota. Anzu wyliei was named in 2014 by Carnegie Museum paleontologist Matt Lamanna and three of his colleagues.

Shopping cart symbol

by Patrick McShea

The shell-encrusted shopping cart in We Are Nature would get lots of visitor attention even if it weren’t suspended from the ceiling. Hundreds of zebra mussels coat the familiar contraption, creating an eerily appropriate symbol for human-altered natural systems:  An empty icon of consumer culture armored by hitchhiking organisms of global trade.

Zebra mussels, a freshwater species native to the Caspian Sea and Black Sea, were unwittingly introduced into the Great Lakes during the 1980s via ballast water dumped by ocean-crossing cargo ships. The creature’s rapid dispersal since then has been attributed to the passive drifting of tiny larvae and the ability of mature zebra mussels to attach to boats moving between the lakes and adjacent river systems.

As invaders, zebra mussels have profound effects on ecosystems. They feed by filtering tiny organisms from the water, and by sheer numbers can out-compete fish larvae and native mussel species dependent on the same food source. Zebra mussels attach to any submerged hard surface. Their profusion attracts attention when it results in clogged water in-take pipes, but not necessarily when thousands of the striped fingernail-sized creatures occupy physical positions atop existing beds of native freshwater mussels.

At Carnegie Museum of Natural History, concern for the health of our region’s diverse population of native freshwater mussels has a long history.  In 1909, Arnold Ortmann, then Curator of Invertebrate Zoology, termed the disappearance of mussel species “the first sign of pollution of a dangerous character in a stream.” His observation was based upon biological surveys in rivers and streams throughout Western Pennsylvania, fieldwork performed during a time of rapid industrialization that garnered the museum an irreplaceable collection of local mussel shells.

Shells of  Potamilus alatus, or pink heelsplitter, a native freshwater mussel  in the Carnegie Museum of Natural History Section of Mollusks.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences of working at the museum.

These fossils were found in a quarry in Solnhofen, Germany, which was once a series of shallow, tropical lagoons. The environmental conditions at Solnhofen resulted in remarkably preserved fossils of Late Jurassic plants, invertebrates, fish, reptiles, and bird species like these fossils on display in Dinosaurs in Their Time.

Sasquatch Squash

Have you ever seen a pumpkin as big as a small car growing in a nearby field?

Probably not, as pumpkins are naturally pretty modest-sized squashes. However, with a little manipulation and some closed cross pollination, people have figured out how to make pumpkins grow to colossal sizes, making them a great example of how humans can impact and alter nature.

The museum is exploring how people are changing our planet in the new exhibition We Are Nature: Living in the Anthropocene, which opens October 28.

The Anthropocene is the concept that human activity has had such a profound and pervasive impact on the planet that effects will be present in the fossil record millions of years from now.

Before the opening of the exhibition, which will feature specimens from the hidden collection, interactives, and more, the museum will have a giant orange delivery to kick off the conversation!

Local growers Dave and Carol Stelts grew a pumpkin that’s nearly 2,000 pounds that will be on display in the museum’s Sculpture Courtyard.

It takes more than a wave of a wand and the magic words “bippity boppity boo” to get pumpkins to grow this large.

Dave said this particular pumpkin was planted in June and grew 45-50 pounds a day for three consecutive weeks to reach its colossal size! He said it came from a “super seed” created by cross breeding large pumpkins.

The pumpkin will arrive by truck October 15 and will be on display for several months until it begins to rot. Come check it out!

Humanity and the environment are connected in new and complicated ways in the Anthropocene­—the proposed geological era in which we now live. Learn more in Carnegie Museum of Natural History’s new exhibition We Are Nature­: Living in the Anthropocene, opening October 28.