Your Fave Is Problematica

Sometimes, extinct animals are famous, well-understood, and known from many complete fossils. This blog is not about those times. 

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A collection of obscure and enigmatic life

I’m bringing this blog back, and also going to be cross-posting on Wordpress

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The engimatic Dendrogramma, which I previously covered here, has turned out to be a siphonophore, a type of colonial cnidarian.

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A new scientific paper, published today, shows that the long-enigmatic Tully Monster is a lamprey!

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Your Fave is Problematica: Balochisaurus malkani

Discovered and named by Malkani

Naming a species after yourself is massively narcissistic 

type specimen looks like a rock

probably a badly preserved Isisaurus or something

Or maybe it’s just a rock

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Gluteus

Despite the caption, these are specimens of Gluteus minimus (source)

Species: G. minimus

Etymology: Presumably named for the fossils’ resemblance to butts

Age and Location: Devonian of Iowa

Classification: Eukarya: Metazoa: ?Bilateria: incertae sedis

Thousands of these fossils, also known as “horse collars,” have been collected, and every single one of them is asymmetrical in the same direction. Because most organisms are symmetrical, fossils tend to be either symmetrical or come in mirror-image pairs, so that alone makes these strange. Some invertebrates, especially mollusks, are asymmetrical, however, though even in asymmetrical mollusks different individuals are mirror images of one another.

These fossils are solid, with internal structure, so this is not the external appearance of some bivalve or brachiopod. In fact, no animal hard part ever found bears a plausibly close resemblance to these fossils. One surface has growth lines, which provides the only clear evidence of any sort of biology for whatever organism produced these. Of all the various unlikely options, perhaps the most plausible is that it is an extremely unusual gastropod shell of some kind, but the microstructure of the shell is nothing like that of a mollusk, so these remain a total mystery.

Sources:

Davis RA., Semken HA. 1975. Fossils of uncertain affinity from the Upper Devonian of Iowa. Science 187:251–254.

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Your Fave is Problematica: Struthiosaurus

Its name means “Ostrich reptile”

naturally, it’s a slow-moving, armored quadruped

I suppose I should just be glad it’s not a synapsid of some kind.

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Pectinifrons

Species: P. abyssalis

Etymology: “Comb of leafy branches,” after its shape

Age and Location: Ediacaran of Newfoundland

Classification: ?Eukarya: incertae sedis: Rangeomorpha

Pectinifrons is a rangeomorph, and so broadly similar to Fractofusus, which also was a sessile organism that reclined on the surface, and with which it shared a presumed osmotrophic lifestyle and fractal anatomy. However, despite the simplicity of their body plans, there was still substantial variation between different genera. Pectinifrons was an enormous organism by Ediacaran standards, with the largest individuals being nearly a meter long. Unlike Fractofusus, which lay flat on the seafloor, Pectininfrons was taco-shaped, with its midline lying on the seafloor and two rows of fronds sticking upward. While superficially it resembled a folded Fractofusus, though, it appears to have grown differently: all Fractofusus have the same number of fronds and are essentially identical except for size, while larger Pectinifrons have more fronds. This suggests that Fractofusus developed an adult morphology early in life and simply grew by expanding itself, whereas Pectinifrons grew by lengthening the midline of its body and growing additional fronds. Such a dramatic difference in growth strategies suggests that the rangeomorphs might be more diverse than previously thought. What kind of organism rangeomorphs are--or if they’re a single kind of organism at all--remains unknown.

Sources

Bamforth EL., Narbonne GM., Anderson MM., Bamforth EL., Narbonne GUYM., Anderson MM., Crescent S. 2008. Growth and Ecology of a Multi-Branched Ediacaran Rangeomorph from the Mistaken Point. Journal of Paleontology 82:763–777. Hoyal Cuthill JF., Conway Morris S. 2014. Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan. Proceedings of the National Academy of Sciences of the United States of America.

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Your Fave is Problematica: Sarcolestes

its name means “flesh robber”

naturally, it was a slow-moving herbivore

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Fractofusus

Fractal models of F. andersoni (top) and F. misrai (bottom) from Cuthill and Conway Morris 2014

Species: F. andersoni, F. misrai

Etymology: “Fractal spindle,” after its shape

Age and Location: Ediacaran of Newfoundland

Classification: ?Eukarya: incertae sedis: Rangeomorpha

Fractofusus is a genus of Ediacaran organism even stranger than yesterday’s Ernietta; like all rangeomorphs, its body plan was essentially defined by a fractal branching pattern--a pattern followed so closely that the genus and species within it can be diagnosed mathematically. Both known species essentially were a fractally-branching network of cells that formed a biconvex spindle-like shape. F. misrai, the longer (up to 40 cm) and more spindle-shaped species, is the younger of the two; it is possible that it is a direct descendant of F. andersoni.

Like most Ediacaran organisms, Fractofusus was an immobile osmotroph. . Due to its fractal branching (and therefore high surface area-to-volume ratio), Fractofusus were well-suited to this lifestyle and probably could obtain all of its nutrients trough direct diffusion, without any distribution of nutrients within the body. In life, it laid flat on top of the microbial mat that covered the seafloor in Ediacaran times, deep underwater. Fractofusus, like many Ediacaran animals, appears to have had no distinct "breeding season.” The young of Fractofusus, whatever they may have been like, were probably planktonic. Once a population was established in a given site, individuals could possibly have reproduce asexually by sending out runners, like some plants do today.

Sources:

Darroch S a. F., Laflamme M., Clapham ME. 2013. Population structure of the oldest known macroscopic communities from Mistaken Point, Newfoundland. Paleobiology 39:591–608.

Hoyal Cuthill JF., Conway Morris S. 2014. Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan. Proceedings of the National Academy of Sciences of the United States of America.

Laflamme M., Xiao S., Kowalewski M. 2009. Osmotrophy in modular Ediacara organisms. Proceedings of the National Academy of Sciences 106.

Mitchell EG et al. 2015.  Reconstructing the reproductive mode of an Ediacaran macro-organism. Nature 524:343-346.

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Your Fave is Problematica: Thotobolosaurus

it’s named “trash heap lizard”

“trash heap” is an appropriate description, because:

it was found in a trash heap

it’s a prosauropod, and prosauropods are awful

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Your Fave is Problematica:  Yaverlandia

When first found, it was interpreted as a partial skull of a pachycephalosaur

Naturally, it turned out to be a partial skull from a maniraptor

because of course pachycephalosaurs and maniraptors have similar looking skulls???

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Ernietta

Species: E. plateauensis

Age and Location: Ediacaran of Namibia

Classification: ?Eukarya incertae sedis: Erniettomorpha

Ernietta is an iconic Ediacaran organism, and like most such organisms, its phylogenetic affinities are totally unknown, although like many other Ediacaran organisms, it may well be a stem-group animal. All we know for sure was that it was multicellular, but not apparently similar to any living multicellular organisms. A trait that defines the ‘erniettomorph’ body plan is a body  The body of Ernietta was composed of essentially undifferentiated tubes of tough organic material. It appears to have lived mostly buried in the sand, with two fan-like fronds projecting into the water. Members of the genus seem to have lived together in large groups, perhaps as a consequence of their mode of reproduction.

Unlike all extant macroscopic organisms and like many other Ediacaran organisms, Ernietta probably were osmotrophic--that is, they fed exclusively by passively absorbing nutrients from the water around them. This was possible as a result of its being essentially a sediment-filled bag, so that most of its body volume was actually just sand. The tubes that comprised the fan-like structures probably primarily served in osmotrophy while the others were structural and served to anchor the organism, however, there is no clear morphological distinction between different body regions. 

Sources:

Ivantsov AY., Narbonne GM., Trusler PW., Greentree C., Vickers-Rich P. 2015. Elucidating Ernietta: new insights from exceptional specimens in the Ediacaran of Namibia. Lethaia.

Laflamme M., Xiao S., Kowalewski M. 2009. Osmotrophy in modular Ediacara organisms. Proceedings of the National Academy of Sciences 106.

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Yuyuanozoon

Species: Y. magnificissimi

Etymology: “Yu Yuan animal,” after an old name for the region where the type specimen was found

Age and Location: Early Cambrian of China

Classification: Eukarya: Opisthokonta: Metazoa: Eumetazoa: Bilateria: ?Deuterostomia: ?Vetulicolia

Yuyuanozoon is a large vetulicolian, with all the taxonomic confusion that that taxonomic assignment implies. The only known specimen is from an individual 20 cm long. It consisted of a large, fusiform anterior region and a relatively short and simple segmented ‘tail’. Like all vetulicolians, it was blind and lacked any obvious external structures aside from gill slits, segmentation, and a mouth. As it had only a small, fairly cylindrical tail and lacked keels that might serve to have stabilized it, Yuyuanozoon was probably a poor swimmer. Like all vetulicolians, Yuyuanozoon exhibited a variety of confusing traits. Besides the arthropod-like segmented cuticle, Yuyuanozoon appears to have an atrium, an internal cavity that surrounds the pharynx in tunicates. This trait makes Yuyuanzoon one of the most convincingly deuterostome-like, or even tunicate-like, vetulicolians. 

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Your Fave is Problematica: Boreonykus

Based on part of a frontal bone

Third time’s the charm?

Nope. Might not be a dromaeosaurid either.

You know what? I give up. Why do people keep naming dromaeosaurids for part of a frontal? Whyyy?

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Your Fave is Problematica: Saurornitholestes sullivani

Based on part of a frontal bone

A frontal bone initially referred to S. robustus

Only removed from S. robustus because that turned out to be an invalid troodontid

If at first you don’t succeed, try, try again, I guess?

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Kakuru

Species: K. kujani

Etymology: “Kakuru,” a rainbow serpent deity in Australian Aboriginal mythology

Age and Location: mid-Cretaceous of Australia

Classification: Eukarya: Opisthokonta: Metazoa: Eumetazoa: Bilateria: Deuterostomia: Chordata: Olfactores: Vertebrata: Gnathostomata: Eugnathostomata: Euteleostomi: Tetrapoda: Amniota: Sauropsida: Sauria: Archosauromorpha: Archosauria:  Avemetatarsalia: Ornithodira: Dinosauromorpha: Dinosauriformes: Dinosauria: Saurischia: Eusaurischia: Theropoda: Neotheropoda: Averostra: ?Tetanurae: ?Orionides

Kakuru is not as notable for the quality of its fossil as it is for how the fossil is preserved: the type specimen, a tibia, is made of opal. Kakuru was a gracile, small theropod of some kind and one of the only such dinosaurs known from Australia. It’s possible that Kakuru is the only known Gondwanan oviraptorosaur.

Sources:

Barrett PM., Kear BP., Benson RBJ. 2010. Opalized archosaur remains from the Bulldog Shale (Aptian: Lower Cretaceous) of South Australia. Alcheringa: An Australasian Journal of Palaeontology 34:293–301.

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Your Fave is Problematica: Saurornitholestes robustus

Based on part of a frontal bone.

Not actually a species of Saurornitholestes 

It’s not a weird dromaeosaurid, it’s a perfectly normal troodontid.