A ten pound frog frog lived in ancient Madagascar

October 9, 2017 • 1:15 pm

A frog that could swallow a small theropod dinosaur? Well, maybe: it was large enough, and weighed in at a hefty ten pounds (4.5 kilograms). This animal, with the clever name of Beelzebufo, was first described in 2008, but a new paper in PNAS by Susan Evans et al. (reference and free link below), describes a full species, Beelzebufo ampinga, based on a larger sample of fossils from Madagascar. The name is scientifically given and described as follows:

Etymology. The generic name is based on Beel’zebul (Greek), Devil, and Bufo (Latin), toad, in reference to the size and probable life appearance of this anuran; the specific epithet, ampinga (Malagasy), means shield, in reference to cranial hyperossification.

Here’s an artist’s reconstruction of B. ampinga next to a normal frog and a pencil. Its skull was up to eight inches wide, its length was about sixteen inches (40 cm) and it’s been described as having the size and appearance of a “squashed beach ball.” It lived about 65-70 million years ago, and may be the largest frog that ever lived. We’ll never know for sure given the incompleteness of the fossil record and the fragility of frog bones, but it’s a big ‘un:

The animal was reconstructed from bits of its skull and vertebrae, and part of its pelvis. Here are some fragments; if you want to see what they are, go to the paper.

And the reconstruction, with the discovered fossilized parts in white and the presumed remainder stippled. The caption gives two living frogs for a size comparison:

(Fig 2 in paper): (A) Skull reconstruction showing parts preserved (white areas, Left) and distribution of pit-and-ridge ornament (stippling, Right). (B) Skeletal reconstruction and inferred body outline of average-sized (skull width, 200 mm; SVL, 425 mm) adult female *B. ampinga* based mainly on *Lepidobatrachus* asper (32). White areas indicate parts represented by fossil specimens. For size comparison, dorsal view silhouettes of *Ceratophrys aurita* (the largest extant ceratophryine) (C), and *Mantidactylus guttulatus* (the largest extant Malagasy frog) (D), are shown. cp, crista parotica; fm, foramen magnum; frp, frontoparietal; mx, maxilla; n, nasal; pmx, premaxilla; qj, quadratojugal; qu, quadrate; sq, squamosal. (Scale bars: 50 mm.)

A new article in National Geographic gives a layperson’s take (the paper itself is full of arcane vertebrate paleontology):

These largely terrestrial frogs may have been as ill-tempered and aggressive as their living relatives, the ceratophyrines of South America, scientists say. Ceratophyrines are nasty sit-and-wait predators that are eager to snap at just about anything that happens by, experts note. The ancient devil frogs may have snatched lizards, small vertebrates, and possibly even hatchling dinosaurs with their huge mouths and powerful jaws.

Scientists announced Beelzebufo in February 2008 more than a decade after the first bits of fossilized remains from the species were found. Its name is derived from Beelzebub, Greek for “devil,” and bufo, Latin for toad. Ampinga means “armored,” describing the prominent cranial shield the species had on its head.

One sidelight of interest: its closest relatives are not on Madagascar, but on the South American mainland, and it’s very different from living and fossil frogs on Madagascar. The conventional wisdom is that the land that now comprises the conglomorate of Seychelles + Madagascar + the Indian subcontinent drifted away from Antarctica/Australia/South America about 120 million years ago. But there is some evidence from other groups that there were physical links between Madagascar + India and South America up to about 80 million years ago in the late Cretaceous—when this frog lived. The fact that this frog lived at that more recent period, and has its closest affinities with frogs from South America, supports the latter hypothesis, though not strongly. Another alternative is that the ancestors of this frog were simply one-off survivors that floated away from South America over 100 million years ago and weren’t part of the radiation of other frogs on Madagascar. A third alternative, which is the least likely, is that its ancestors somehow made it over the ocean from South America about 70 million years ago, perhaps on a floating raft of vegetation. That seems unlikely, however, as salt water is deadly to amphibians.

It would be lovely to see this thing alive, but alas, the inexorable course of evolution prevents that. Maybe George Church can bring it back!

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Evans, S. E., M. E. H. Jones, and D. W. Krause A giant frog with South American affinities from the Late Cretaceous of Madagascar. PNAS 2008 105 (8) 2951-2956; published ahead of print February 19, 2008, doi:10.1073/pnas.0707599105

Giant “paleoburrows” dug by extinct mammals

June 24, 2017 • 3:15 pm

In the last few years, geologists have been finding—mostly in Brazil—large “paleoburrows” that were almost certainly dug by large, extinct mammals such as giant ground sloths. These burrows can be up to 3000 feet long (!) and 5 feet wide, though the very long ones were surely dug by many individuals over many generations. The shape of the burrows, and the fact that they bear distinct claw marks, are sure signs they were dug rather than being natural caves (the beasts could also have “improved” existing caves, but geologists think that’s unlikely).

Here’s what the excavations look like, from a summary of paleoburrows in Discover Magazine (captions from the site):

Looking into a large paleoburrow in Brazil. (Courtesy: Heinrich Frank)

Inside the first paleoburrow discovered in the Amazon. It’s nearly twice as large as the second-largest known burrow, located elsewhere in Brazil. (Credit: Amilcar Adamy/CPRM)

Here’s evidence that these are the products of animal activity: claw marks:

Claw marks are clear signs from the engineers who dug the tunnel. (Courtesy: Heinrich Frank)

A close-up of the scratches (sadly, there’s no scale, but you can see from the above that the animals must have been BIG.

A closer look at those claw marks. (Courtesy: Heinrich Frank)

The caves are at least 8,000 to 10,000 years old, which is when the suspected excavators went extinct. And those suspects are both giant ground sloths (Megatherium) and giant armadillos (glyptodonts). The sloths, one of the largest land animals that ever lived, were this big (below) and, at least according to Wikipedia, could weigh up to 4000 kilograms (4 “tonnes”) and stretch 20 feet from head to tail. Some were as big as modern elephants, and, like the pachyderms, they were herbivores:

Another candidate, the giant armadillos, or glyptodonts, were also huge, weighing about 2 “tonnes” (2000 kg) and extending about 11 feet: they were the size and weight of a VW Beetle. Here’s one:

But the caves with scratches on the roof were probably made by sloths, which could rear up on their hind legs. Based on the shape of the excavations, Heinrich Frank, a Brazilian geologist, thinks they were made this way:

But why did they need these caves, particularly such long ones? It’s still a mystery:

. . . the sheer size of the burrows is something that Frank and his colleagues are still trying to explain. Whether prehistoric sloths or armadillos were responsible, the burrows are far larger than would be necessary to shelter the animals that dug them from predators or the elements.

The giant armadillo, the largest living member of the family, weighs between 65 and 90 pounds and is found throughout much of South America. Its burrows are only about 16 inches in diameter and up to about 20 feet long.

“So if a 90-pound animal living today digs a 16-inch by 20-foot borrow, what would dig one five feet wide and 250 feet long?” asks Frank. “There’s no explanation – not predators, not climate, not humidity. I really don’t know.”

You tell me! It’s cool enough that we have fossil habitats like this.

h/t: Michael

Readers’ wildlife photos

January 11, 2017 • 7:30 am

Please keep your photos coming in; I have a decent backlog, but you know how I worry. . .

Today we have some photos of fossilized wildlife, all taken by reader Mark Sturtevant. His notes are indented.

As a change from the usual stuff that I have been submitting, I thought to share pictures of some specimens that I keep in what I call my Cabinet of Mystery. Most objects are fossils or bones that I have either found or purchased over a lifetime.

I expect that a good percentage of humanity has at one time possessed a fossil fish known as Knightia from the Eocene Green River formation. But this Lagerstätten is also rich with other fossils. The first two pictures are of aquatic insect larvae from that location. Although it was labeled as tsetse fly larvae from the gem and mineral show where I picked this up, these are more likely horsefly larvae. The second picture is a close-up view showing the paired posterior spiracles that fly larvae often have, which in this case would have been used for breathing air while under water.

The second picture is a close-up view showing the paired posterior spiracles that fly larvae often have, which in this case would have been used for breathing air while under water.

I lived in San Diego for many years, and exposed areas of Quaternary sandstone are common over much of the area. While hiking in a park, I found this large fossil clam in a cliff about a mile inland from the ocean. I do not know the age, but it does strongly resemble a modern clam known as Tresus.

What is interesting about this specimen is that it appears that the clam had survived a serious injury which had healed.

The large fossil that follows was purchased, and it is a portion of a Cretaceous mollusk known as a Baculite. The total specimen would have been several feet long. I am a little mystified of their technical classification and anatomy (and so I would like to be corrected by any reader), but as I understand it these were a kind of shelled cephalopod, related to the modern chambered nautilus, only Baculite shells were straight instead of coiled. What is actually seen here is not really a preserved shell, which I think was paper thin and had dissolved away long ago. What remains is really a mold formed by sediments that infiltrated the interior of the shell after the animal died. One can still see that the shell was segmented into a series of chambers, and articulated together by intricate sutures. Some of the segments of rock actually wiggle a little, but are still locked together.

The Cabinet of Mystery also contains various skeletal remains. Here is a skull of an American opossum that I had since I was maybe 14. Through that time I would sometimes pick up road kill and learn what there was to learn of it by dissection in my bedroom/laboratory. With this one I eventually cut off the head, and waited for my parents to leave the house for the day so that I could boil the head in a pot on the stove, thereby making it a lot easier to remove the soft tissue. I am sure that I am not the only one who does not tell my parents everything! I do not know of many skeletal characters that identify a marsupial, although some obvious ones here are the small brain case and the numerous premolar and molar teeth. The spatters of paint were from a painting that I did of something many years later.

Happy Thanksgiving (and a fossil turducken)

November 24, 2016 • 8:15 am

Today’s Bloom County cartoon, courtesy of reader Stash Krod (click to enlarge):

Reader John W. sent this salacious Thanksgiving cartoon (if you don’t know what a “turducken” is, go here):

And, for some biology on this day, we have an item reported in September by Discover Magazine and National Geographic: a “preshistoric turducken”. Yes, it’s a three-in-one fossil find discovered in Germany’s Messel Pit, a remarkable cache of fossils from the Eocene, deposited around 47 million years ago. (Messel is also a UNESCO World Heritage site.) Like a turducken, it shows three species inside each other, though unlike a turducken, the fossils are sequential members of a food chain. Here’s the fossil (the interpretation is below):

The white arrow above indicates the tip of the lizard’s snout resting inside the snake.

And this is what happened (from National Geographic):

Forty-eight million years ago, an iguana relative living in what’s now Germany scarfed down an insect with a shimmering exoskeleton. Soon thereafter the lizard’s luck changed—when a juvenile snake gulped it down headfirst.

We know this happened because the snake had the spectacularly bad luck to end up in a death trap: the nearby Messel Pit, a volcanic lake with toxic deep waters and a possible knack for belching out asphyxiating clouds of carbon dioxide.

It’s unclear if the lake poisoned or suffocated the snake, fates that more often befell the area’s aquatic and flying creatures. Most likely, it somehow died near the lake and was washed in. But no more than two days after eating the lizard, the snake lay dead on the lake floor, entombed in sediments that impeccably preserved it, its meal, and its meal’s meal.

And that’s a very good thing. That fossil, recently described in Palaeobiodiversity and Palaeoenvironments, is only the second of its kind ever found, revealing three levels of an ancient food chain nested one inside the other in paleontology’s version of Russian nesting dolls—or its culinary equivalent, a turducken.

“It’s probably the kind of fossil that I will go the rest of my professional life without ever encountering again, such is the rarity of these things,” says Krister Smith, the paleontologist at Germany’s Senckenberg Institute who led the analysis and a National Geographic/Waitt Grant recipient. “It was pure astonishment.”

Here’s the reveal (illustration from Kreister R. Smith): the snake is in white, the lizard, Geiseltaliellus maarius, is in orange, and the insect inside the lizard’s gut is in turquoise:

This isn’t the first fossil showing three levels of a food chain. A 2008 paper in the Proceedings of the Royal Society reports a fossil shark that ingested an amphibian that itself ingested a fish. Thus, unlike the one above, all are vertebrates. Here’s that one, about 300 million years old, which is a little harder to suss out. The caption comes from the Royal Society paper:

f1-medium — (from paper): Figure 1 Triodus sessilis with ingested prey items. (a) Photograph of a specimen from the Lower Rotliegend of Lebach, southwest Germany (UHC-P 0682). (b) Line drawing of digested temnospondyl larvae. Left: an almost complete specimen of Cheliderpeton latirostre with the remains of ingested juvenile acanthodian. Right: skull of Archegosaurus decheni. as, acanthodian scales; br, branchial apparatus; cla, clavicle; ?clei, cleithrum; fem, femur; gs, gastral scalation; fs, acanthodian fin spines; hum, humerus; icl, interclavicle; il, ilium; man, mandible; mc, Meckel’s cartilage; mca, metacarpalia; mta, metatarsalia; na, neural arch; or, orbit; pas, parasphenoid; pf, pectoral fin; pg, pectoral girdle; phal, phalanges; pq, palatoquadrate; ps, xenacanthid placoid scales; r, ribs; rad, radius; sk, skull; sta, stapes; ul, ulna.

The scenario:

If you’re one of those having a turducken today, give us a shout in the comments. I’ve never had one!

h/t: Grania

Earliest organisms: 3.7 billion years old?

September 2, 2016 • 10:00 am

There’s a new paper in Nature that has everyone excited, for it reports what is said to be the earliest evidence for microbial life—”microbial structures” dated 3.7 billion years ago. The paper, by Allen P. Nutman et al. (reference and free link at bottom), describes what are said to be ancient traces of stromatolites—layered colonies of cyanobacteria that trap sediments and are thus fossilized—from a part of southwest Greenland that harbors old rocks.

The earliest previous evidence for microbial life are microfossils dated at 3.4-3.5 billion years old, coming from the Strelley Pool formation of West Australia. (Wacey et al., Nature Geoscience 4:698-702). The Nutman et al. finding, if true, pushes back the known existence of cells by 200-300 million years, no small chunk of time. (There is some evidence, though not very convincing, for carbon of biological origin dating back 4.1 billion years.)

What is the new evidence for 3.7 billion-year-old life? It’s largely structures in dated rocks that Nutman et al. interpret as stromatolites, structures like those shown below (“strom” means “stromatolite”). The pointy structures are identified as the remains of ancient stromatolites, though I wonder why the middle one isn’t labeled “strom”:

nature19355-f1 — Image is inverted because layering is overturned in a fold. b, Interpretation of a, with isolated stromatolite (strom) and aggregate of stromatolites (stroms). Locally, lamination is preserved in the stromatolites (blue lines). Layering in the overlying sediment (red lines) onlaps onto the stromatolite sides. A weak tectonic foliation is indicated (green lines). c, Asymmetrical stromatolite and d, linked domical stromatolites from the Palaeoproterozoic28 Wooly Dolomite, Western Australia. The lens cap is 4 cm in diameter. Image c is left-right-reversed for comparison with panels a, b.

Nutman et al. give other evidence too, including isotopic data, the presence of minerals that said to be biogenic, and the presence of layers (“lamellae”) in the stromatolite-looking bits. But the most touted (and convincing to others) evidence are pictures like those above.

I checked with some well known paleontologists and sedimentologists, however, and they don’t find even the “fossil” data very convincing. (I’ll withhold their names for the time being.) The pointy bits above, they say, could be “flame structures“: simple deformation of clay or mud that occurs when it’s pushed up by heavier overlying layers of sand. This could produce (and has produced) the kind of structures seen in the photo above, but without any presence of life. Further, the layers in the structures might not represent layers of ancient microbes, but simply layers in the underlying mud that, after all, could be produced by successive sedimentation events.

The rest of the evidence, I’m told, may be suggestive of life but hardly convincing. The paper is tough going, which you’ll see if you read it, so all I want to do is note that the evidence for life given in this paper is questioned by some experts.

Nevertheless, we still have pretty good evidence for bacterial cells existing 3.4-3.5 billion years ago, and such cells are pretty complex. That means that life got started pretty soon after the Earth cooled down, roughly 4.3 billion years ago. These cells, after all, had to have undergone a very long period of evolution from the initial replicating molecule (or whatever it was) that constituted the first “life”.

So take this 3.7 billion year date with a grain of NaCl. That doesn’t mean it’s wrong, just that there are formidable problems with finding solid evidence for life in ancient rocks. Not many of those rocks exist on Earth any more, and those that do could have been changed or deformed in a way that would make life hard to detect. Further, the best evidence for life are microfossils like those shown below, but even these are somewhat controversial. Proving that such structures are fossil bacteria rather than inclusions or artifacts is often hard to do.

Nevertheless, the photos below, and other data from the Wacey et al. paper, have convinced most paleontologists that there were microbial cells around 3.4-3.5 billion years ago.

Why do paleontologists fight bitterly about the “first” cells if it’s only a mere matter of 300 million years (!)? Well, there’s cachet to be gained by finding the earliest good evidence for life, but, beyond that, finding complex cells soon after Earth cooled down gives us a good time scale for how long it takes to go from simple chemicals to “life” (I see the origin of “life” as a somewhat subjective point, as it varies depending on your definition). Pushing dates of cells further back tells us that that transition could be even faster than we once envisioned.

ngeo1238-f1 — a,b,e, Clusters of cells, some showing cell wall rupturing (arrows in a,b), folding or invagination (arrow in e). c,d,h, Chains of cells with cellular divisions (arrows). f,i–j, Cells attached to detrital quartz grains, exhibiting cell wall rupturing and putative escape of cell contents (arrow in f), preferred alignment of cells parallel to the surface of the quartz grain (arrows in i), and constriction or folding between two compartments (arrow in j). g, Large cellular compartment with folded walls (arrows).

h/t: Latha Menon

__________

Nutman, A. P., V. C. Bennett, C. R. L. Friend, M. J. Van Kranendonk, and A. R. Chiva. 2016. Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures. Nature, published August 2016, doi:10.1038/nature19355

Readers’ wildlife photos

May 18, 2016 • 7:30 am

Reader James Blilie sent some landscapes, plant, and fungi photos; his notes are indented:

White pine (Pinus stroba) left foreground and red pine (Pinus resinosa) right foreground and cottonwood trees (Populus deltoides), background, along the St. Croix River. Minnesota in the foreground, Wisconsin in the background.

Some newly-emerged leaves (not sure of species):

Skunk Cabbage (Symplocarpus foetidus), an early emergent:

Bloodroot (Sanguinaria canadensis), one of the first-emerging forest plants. The cool spring has slowed all the emergence down.

Mushrooms. After doing a little research, I think these are Coprinellus micaceus:

OLYMPUS DIGITAL CAMERA

And have a new contributor today: Garry VanGelderen, with these pictures taken at Penetanguishene, Ontario, about 80 miles north of Toronto.

Two pics of a Red-headed woodpecker (Melanerpes erythrocephalus) taken yesterday in my backyard.

Finally, lagniappe from reader Bruce Thiel, whose fossil preparations I’ve shown before (e.g., here). These photos were in an email titled, “30 MYO crab starts its return journey to the ocean.” His explanation:

Thirty million years ago, the Oregon coast was 50-70 miles inland. This crab was fossilized in a concretion in the bedrock and over the course of several million years was lifted several hundred feet upward and 50 miles inland. Storms and erosion finally set it free and it started tumbling down the creek on its way back to the ocean. The erosion from tumbling has taken its toll, exposing the remains of the crab inside. Will it make it back to the ocean before being reduced to a grain of sand? In this case, it was rescued and set free with small pneumatic tools to show the remains of the extinct Pulalius vulgaris crab inside.

Readers’ wildlife photographs

April 27, 2016 • 7:30 am

As I mentioned when in Portland, I encountered reader Bruce Thiel at my free will talk; Bruce’s avocation is preparing fantastic fossils that he finds locally. I’ve featured some of his preparations before; have a look, as I’ve never seen anything like them. Using a dental drill and working slowly and meticulously, he produces fossils like the ones below, whose photos just arrived in my email. (Go here to see how a preparation proceeds.) He doesn’t sell them, though preparations like this fetch high prices; instead, Bruce gives them to museums and scientists to study. So let’s have a paleontological “readers’ wildlife” today. Bruce’s notes are indented:

Here are some other interesting crabs I’ve prepared. Background information about the fossils and the discovery and preparation procedure can be found here [JAC: the second link above].

All the crabs shown are about 30 million years old and are Pulalius vulgaris, except for the last picture. This crab in the next two pictures was mashed and not particularly well-preserved—until I got to the eyestalks and claws, so I went as close as I could between the claws. The eyestalks are 1.5cm apart–slightly over 1/2 inch—so there was not a lot of working area.

The next crab was one of three given to the Smithsonian. What looks like googly-eyes are two attached barnacles.

The next two crabs host tube worms, and are at Kent State being studied for epibionts. The chip in the middle of the carapace is what fossils preparers call “the mark of discovery.” Most of the round or oval-shaped concretions are blank or contain bits of wood, shell or decomposed organic material. In working down into the middle of the rock with the pneumatic jackhammer to see what they contain, if one is too aggressive or not paying close attention, one can “nick” the shell with the pneumatic tool as I did in this case. Both crabs have interesting snake-shaped worms lurking on their shell. One of the questions experts would like to answr is if the worms attach while the crab was alive or after death and during decomposition.

This is one of the smaller crabs I’ve worked on. I held my breath when uncovering the tiny claw. My thumbnail is shown for comparison.

These are two Macroacaena schencki crabs from the Keasey Formation, Oregon (33 – 35 MYO). We think the larger and wider of the two is female but determination awaits further research.

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