Archaeopteryx Identity Crisis: Some Broad Connections in Secular Literature

The idea that Archaeopteryx was a dinosaur, rather than a bird, is not a new one. The growing majority of paleontologists do not accept Archaeopteryx’s old status as the earliest bird. This has not so much been due to the new emerging picture of Archaeopteryx (though that has played a part), but rather the discovery of certain dinosaurs, which share features with Archaeopteryx.

Keep in mind that the following research and opinions is based largely on the science of cladistics, which is grounded in the belief in the functionality of macroevolution. For example, many of the authors looked at in the following paragraphs hold to a Deinonychosauria clade. To an evolutionist, a clade is a distinct branch of the evolutionary tree of life. While the presupposition that all animals are descended from the same ancestor is inherently flawed, there is a lot to be gleaned in a baraminological perspective.

Looking at the reasons paleontologists determine the members of a clade helps us translate the data into a form useful to creationists. Archaeopteryx, as an example, might be considered very close on the evolution tree to Velociraptor. They are considered related to each other, not as some random interpretation of the evolutionist, but because they do bear many similarities. In effect, cladistics is a great way to get a preliminary perspective on exactly how alike the various genera are. Whether truly related or not, cladistics shows in a visual format the physical similarity of the organisms.

The discovery of the Chinese fossil species Xiaotingia zhengi has provided a link among deinonychosaurs (Xu et al., 2011). Xiaotingia was most similar to Archaeopteryx and Anchiornis huxleyi (a small carnivore bearing many similarities to troodont dinosaurs and often considered more bird-like than Archaeopteryx in some respects). Actually, Xiaotingia was nearly identical to Anchiornis, especially in the structure of the skull, and both animals were placed in the Deinonychosauria with Archaeopteryx. Interestingly, Archaeopteryx was considered to be slightly more similar to other deinonychosaurs and less similar to birds, when compared to the other two genera. Bringing the data closer to home, if Xiaotingia and Anchiornis are considered deinonychosaurs, then the less bird-like Archaeopteryx has an even higher chance of belonging to the same monobaramin as the less bird-like Deinonychosaurs, such as Velociraptor, than these two species.

And yet, Xiaotingia and Anchiornis are more like troodont dinosaurs than Archaeopteryx. So, if Anchiornis/Xiaotingia and Archaeopteryx are most like each other, but Archaeopteryx is very like the dromaeosaurids (such as Velociraptor), and Xiaotingia/Anchiornis are very like troodonts, what is the creationist interpretation? Well, given that information, there are a couple of possibilities. First, it could be that the extreme similarities to each other is merely coincidental, and the alternate likeness of the Anchiornis/Xiaotingia and Archaeopteryx groups to the Troodontidae and Dromaeosauridae prospectively is evidence that the two groups are not the same created kind. The second perspective would take the evidence in an opposite direction. While the Troodontidae and the Dromaeosauridae represent two different subgroups within the Deinonychosauria, the traits each group shares with Anchiornis/Xiaotingia and Archaeopteryx groups is evidence that they all belong to the same super monobaramin. There is no clear line that can be drawn between the various groups; they all seem to have significant similarities with one another discontinuously. Thus, the two views are, either all are the same created kind, or there are many very similar monobaramins.

Further evidence for the single monobaramin theory has ben uncovered with the new discovery of the troodontid-like Aurornis xui. Seemingly, it has crumbled the barrier between the Archaeopteryx, Anchiornis, and Xiaotingia clade (Godefroit et al., 2013). It is undeniable that the new dinosaur Aurornis xui was extremely similar to the Troodontidae, more so than even Anchiornis, but it was also much more birdlike than the previous finds in many of its features. It appears that Aurornis was a more perfect combination of dinosaur and bird features than even Archaeopteryx. Thus, Aurornis joins the growing number of genera in the Archaeopteryx holobaramin as possibly the most bird-like of the deinonychosaurs, but not the most non-dinosaurian.

Since a lot of this post has dealt with the views and observations of evolutionists on the Deinonychosauria, some explanation is needed. It should be noted that evolutionists do not see birds and dinosaurs as two distinct groups. When an evolutionist says an animal is a bird, in most cases, it in no way detracts from the animal’s status as a dinosaur. All birds are dinosaurs to most evolutionists. However, not all dinosaurs are birds in that perspective, because it is the birds that evolved from the dinosaurs, not vice versa. Keep in mind that these views are present when evolutionists classify dinosaurs, as is discussed throughout this text.

Archaeopteryx has been compared to other dinosaur families in a broader sense. It was illustrated that Archaeopteryx is distinct from the Tyrannosauroidea (including Tyrannosaurus) and Alverezsauroidea, such as Mononykus, which has been believed to be a bird rather than a dinosaur (Xu et al., 2010). It is interesting that the authors of that paper noticed such stark differences between the Deinonychosauria and the Alverezsauroidea, since members of the later group have also been considered birds in the past. However, Archaeopteryx was considered similar to other groups like the Oviraptorosauria, Scansorioperygidae, and especially (but not surprisingly) the Dromaeosauridae and Troodontidae, which are fellow deinonychosaurs. All four groups were considered birds by those authors. Of course, that thinking would also include the iconic Velociraptor as a bird, which will be explored a little later on.

Not all feathered dinosaurs were so bird-like. This is a heterodontosaur, a
kind of herbivorous ornithopod dinosaur. Although they did have
feathers, they are never included as a possible dino-bird candidate
because other feathers of their anatomy clearly differentiate them from the
Deinonychosauria, Oviraptorosauria, and other very bird-like dinosaurs.

Once again, let me remind readers that this is an overview of secular literature and, while much good data has been gleaned, we always need to keep in mind the ultimate goals of this research, one of which is to determine which monobaramin Archaeopteryx belongs to. However, this overview of the literature has brought up an interesting side note and, as was addressed in the first part of this series, if the Deinonychosauria like Velociraptor should be considered dinosaurs, then it would mean that some dinosaurs were feathered. I think this is a notion that creationists need to become comfortable with.


References:

Goedfroit, Pascal, Andrea Cau, Hu Dong-Yu, Francois Escuillie, Wu Wenhao, et Gareth Dyke. June 2013. “A Jurassic Avialan Dinosaur from China Resolves the Early Phylogenetic History of Birds”. Nature. Vol. 498, No. 7454, pp. 359-362.

Xu, Xing, Hailu You, Kai Du, et Fenglu Han. July 2011. “An Archaeopteryx-like Theropod from China and the Origin of the Avialae”. Nature. Vol. 475, No. 7357, pp. 465-470.

Xu, Xing, Qing Yu Ma, et Dong Yu Hu. December 2010. “Pre-Archaeopteryx Coelurosaurian Dinosaurs and Their Implications for Understanding Avian Origins”. Chinese Science Bulletin. Vol. 55, No. 35.

Archaeopteryx Identity Crisis: Feathered Dinosaurs and Creationists

I have been doing a bit of research on the idea of feathered dinosaurs. It started when I was looking at some photographs of the skeletons of Microraptor, Archaeopteryx, Anchiornis, and some other genera. I immediately noticed that the creatures in question were definitely feathered; true, pennaceous, primary flight feathers. And it also struck me that, merely at first glance, these animals look no different from other dinosaurs, namely those belonging to the group known as the Deinonychosauria (which includes Velociraptor). Now, the popular view of the genus Archaeopteryx, among both creationists and evolutionists, has often been that of a bird. And, in creationist circles, it’s the same situation for the other feathered deinonychosaurs. I don’t mind the evolutionists calling Archaeopteryx a bird or a dinosaur or something in between; they speculate within the realm of their own theory on evolution, and I disagree with that starting point.

I just drew this Archaeopteryx last month, and I'm already dissatisfied.
First, in a strictly artistic sense, The hands and the feet get all mixed up so
it is hard to tell exactly how many legs it has at first glance. And,
scientifically, I suppose it is not likely that the hand would move so
independently of the wing feathers. I illustrated the head bald in an
attempt to be more accurate, but I later read that it only appears that way
because the feathers on the head were erased during preparation of the
fossil. Oh well. The pigments (dark wing tips and coverts) are true to what
has been found in the feathers.

However, I don’t like how creationists refer to feathered dinosaurs. It seems they are often making the claim that any deinonychosaur that is found with undeniable feathers is one hundred percent bird. That claim has been made many times about Archaeopteryx in various creationist organizations. I think such a claim is out of place for a number of reasons. First, to say it is definitely a bird is merely to say it is best classified within Class Aves. Such a statement has little to do with creation science at all; it is merely a man-made classification system. Whichever class you place it in is irrelevant. However, I think that what many creationists mean to say is that Archaeopteryx is more like the members within Aves than those members within the Dinosauria. That claim is also of little importance because it is very clear that Archaeopteryx has many features in common with both groups. Why does it matter that Archaeopteryx is more like one than the other? Being adamant that Archaeopteryx is a bird because it has feathers (and a number of other features) is like saying that the platypus is better classified as a bird because it lays eggs and has a bill (among other features). These kinds of statements, whether right or wrong, are irrelevant to the creation evolution debate. As is demonstrated by the platypus, God has not created all animals to fit into a specific order, or class, or any other manmade classification method.

But what did God really say? That they should “reproduce after their kinds.” The “kind” is God’s classification of his creatures and, from a creationist’s perspective, each animal “kind” was created and diversified from each one’s ancestors. And creationists are very aware of this Biblical principle. They have even composed their own classification system to accommodate God’s perspective. For example, a “kind” is defined in their system as a monobaramin. A group of similar animals that may be one created kind (monobaramin) but could easily represent many similar created kinds is defined as a holobaramin. These terms, very useful in the study of created kinds (baraminology), will reappear throughout this research series. So the valid question for the creationist to ask himself is, exactly what monobaramin does Archaeopteryx belong to? That is the first question that this paper aims to address.

Of course, there are some words in society used to refer to certain clumps of animals, such as “birds” or “dinosaurs.” True, they are manmade. However, they are useful in describing these broad groups in an understandable manner to fellow English-speakers. My own personal view of Archaeopteryx (well supported by the evidences examined later on, I believe) is that there is no reason not to consider Archaeopteryx a dinosaur. Along with many paleontologists, I think Archaeopteryx is aptly classified within the Deinonychosauria (though evolutionists do so for different reasons), keeping in mind it is just a human classification. Thus, if Archaeopteryx is a deinonychosaur, it is also a dinosaur. The deinonychosaurs (such as Velociraptor) have nearly universally been considered dinosaurs, though one may make a case that they are really birds (in fact, many evolutionist do believe that Velociraptor and the deinonychosaurs were all dinosaurs “advanced” enough to be considered birds). I will simply go along with the majority that the deinonychosaurs are dinosaurs. If you disagree at this time, bear with me as we investigate Archaeopteryx, because I will likely frequently refer to it (and other members of the Deinonychosauria) as a dinosaur.

Archaeopteryx has always been of interest to creationists because of its publicity as a “missing link” or “the first bird.” Of course, both terms are saturated with evolutionary thinking, so it is no surprise that creationists should investigate. A “missing link,” the way it is usually meant, is not compatible with creationism. So what does a creationist do with an animal that appears to be part bird and part dinosaur? Before the many better-preserved Archaeopteryx specimens had been uncovered, some concerned creationists made the claim that Archaeopteryx was really just a coelurosaur dinosaur with fraudulent feather impressions and wishbone. In light of today’s wealth of specimens and data, however, fraud, in any practical sense is impossible. Besides the many well-preserved specimens with no sign of fraud, the specific design of Archaeopteryx for its ecological niche very clearly defies such a view. After all, if an animal is so perfectly designed for gliding or flight in the bush in every aspect of its anatomy, with no inconsistency, it is very unlikely to be a fake. This design will be demonstrated later on. Indeed, the vast majority of creationists today do not consider Archaeopteryx as anything like a fraud. Thus came the claim that it was “one hundred percent bird.”

Anyone writing to convince his readers of anything (even if it is a right or noble case) has an agenda. And creationists (such as myself) are no different. We often attempt to emphasize certain discoveries that fit with what we expected or desire, while seemingly ignoring those that do not fit in. I feel that most creationists have been negligent of a wealth of information and research that has been conducted on Archaeopteryx and other feathered dinosaurs that paints a picture of Archaeopteryx, not as “one hundred percent bird,” but as a member of a unique kind of dinosaur. Creationists should not unnecessarily try to make Archaeopteryx less dinosaur-like than it really was, but acknowledge that the Deinonychosauria (along with Archaeopteryx) were a unique group, perhaps best classified in the Dinosauria, that had characteristics shared by both birds and dinosaurs. This research aims to make it clear that the Deinonychosauria represent a viable holobaramin and possibly a monobaramin that includes Archaeopteryx, Microraptor, Velociraptor, Troodon, and others.

This should not be alarming to creationists. A seeming mix of traits does not prove macroevolution to be true. It merely illustrates a mixed lifestyle. The second goal of this paper is to paint a picture of Archaeopteryx (and the other members of the Deinonychosauria) as a creature well designed for its own ecological niche. As the characteristics of Archaeopteryx are explored and compared to other dinosaurs, an accurate picture of Archaeopteryx in life can be created.

Ice Age Elephant Death Date Postponed

A genera of extinct elephant (Palaeoloxodon) has long been known from northern China under the name Elephas maximus (the Asian elephant) because it was thought to be the same as this extinct species. Not only is the name of the animal debated, but now the date of the animal has been questioned. Some teeth and bronze artifacts have been uncovered that evolutionists have dated at 3000 years ago (as opposed to the 10000 years originally postulated for the the original fossils).

Palaeoloxodon naumanni as it might have looked in life. Note the smaller ears and trunk, compared to Elephas maximus, for a habitat with cooler winters in the north China Ice Age. I've also given it two fingers on its trunk.

Of course, if the new remains really are Palaeoloxodon (the bronze artifacts have two fingers on the trunk as opposed to the one finger for the Asian elephant) then the animal did survive later than previously believed. However, the dates evolutionists place on bones aren't trustworthy to Christians because of the presupposed age of the Earth. Rather than a 7000 year difference, it was probably only a few hundred (just throwing that out there).

Warwicker, Michelle. "Extinct Elephant 'Survived Late' in North China". BBC Nature News. http://www.bbc.co.uk/nature/20678793.

The Creationist Dinosauria

The greatest dream of my early teens was to write a book on everything and anything to do with dinosaurs all from creationist perspective. I began work on it right away in the late 1990s, completing a series of books with every genera of dinosaur I knew illustrated on the pages, which I stapled together. There were some 15 books. As I grew more mature, my intentions got more serious and new ideas blossomed.

A hypothetical drawing of the tyrannosaurid Alectrosaurus olseni. It was probably very similar to Albertosaurus.

The intentions of this research project began in early 2012 as a desire for a complete creationists analysis of all fossil-bearing rock formations. The idea was to recreate these habitats with an emphasis on how the organisms interacted and what the habitat was like. Puzzling over where to start on such a massive comprehensive project, I concluded that it would be impossible, for all practical reasons, to attempt this comprehensive analysis with myself as the sole writer. Because my primary interest was in extinct reptiles, particularly large reptiles like dinosaurs, I decided to only include the formations that contained dinosaur remains. This is still the plan today but it would take far to much time to complete this in a single project, a present.

Tyrannosaurus rex might have looked something like this.

As a result of these conclusions, I have balanced my emphasis to include the baraminology of the dinosaurs. I will also lessen up on my meticulous research of the flora and fauna of the formations (though complete lists of species had been formed for the Hell Creek, Ferris, Laramie, and other Maastrichtian type habitats). The goal is to gain a better understanding of the dinosaurs themselves; how they looked, behaved, and interacted. I found that much of this, especially appearances, was dependant on the baraminology of the dinosaur. For example, if Microraptor was part of the Dromaeosauridae monobaramin, then raptors would likely have been feathered, a theory that doesn’t sit well with very conservative creationists, but is accepted by creationist professionals in the paleontology field.

I needed to start somewhere so I chose the most famous dinosaur of all time, Tyrannosaurus rex, and began a deep study of the various formations where T. rex is found. My analysis lead me to believe that Tyrannosaurus habitat was not unlike that of the semi-tropical regions of the southern United States, complete with redwood forests and numerous cypress swamps. Besides the nearly entirely modern flora, many of the creatures are almost identical to those that fill correlating ecological niches today. Among fish, there were gars and bowfins. Turtles included emydids and trionychids. Modern species like cormorants and other water birds flourished in the lake-riddled habitat. What I found was not an alien prehistoric world but a beautiful, colorful, functioning ecosystem.

For the sake of my impatient nature, my present research will detail only tyrannosaurs. To begin, I will define the tyrannosaur monobaramin and describe exactly what should be included in this kind.

Survival of the... Not Fittest?

A Christian Creationist's Perspective on the Family Tree and Baraminology of the Platypus (Ornithorhynchidae).

To construct the family tree of the platypus, I had to research a number of scientific articles and museum sites with photographs and descriptions. The fossil record of monotremes is sparse and, while there seems to be enough being dug up in Australia, the rest of the world seems absent of specimens. The only nearly definite platypus fossils before the flood belong to Odurodon. Other monotreme genera like Kollikodon, Teinolophos, Steropodon, and Kryoryctes are too fragmentary to say what they are for certain and the evolutionists who described them are obviously biased, believing that monotremes evolved in Australia. Below is the family tree of the platypus for starters, and an explanation of the tree after that.

This jaw fragment is all that is known
of Kollikodon. In all honesty, I can't
pinpoint anything that would single it
out as platypus, racoon, or anything
else for that matter. Just unprofessional
 eyeballing, it dose look a bit like a
young 'coon. In any case, I highly doubt
that this is an example of a Pre Flood platypus.

Steropodon is no better. Though, from my point of view,
the teeth do look a little more like those of Obdurodon.

In Teinolophos, though the teeth look like platypus 

enough, the back end of the jaw hardly resembles that of a the modern platypus jaws I've seen. This drawing is acomposite of both right and left mandibles for the mostand accurate perspective.

Vertically on the map, time increases from bottom to top, starting at the creation, through the Flood and Ice Age, to the present. Living species are represented by a dot at the end of a branch and rectangles represent extinct species. In the case of Ornithorhynchus, fossils have been found in Ice Age deposits. The entire limb containing Steropodon, Teinolophos, and Kollikodon is dubious, and I represented this with a large question mark at its base. Specifically, I have doubts about Kollikodon ritchiei and this is noted by a large question mark by the genus name. 

Obdurodon dicksoni from a lateral view. Besides the two teeth protruding
out of the maxilla, it is practically identical to the skull of the platypus.

Kollikodon ritchiei is also controversial because only a single opalised jaw fragment is known. If it is a platypus, the length of the creature would have been nearly a meter, much larger than today's platypus (Australian Museum). Like Kollikodon, both Teinolophos and Steropodon had double-rooted molars, rather than the multirooted molars of modern monotremes. Teinolophos and Steropodon are placed closer together on the tree but, in hindsight, Steropodon and Kollikodon might be the more closely related between the three because of their size and geographical similarity. Both Steropodon and Kollikodon are fairly large (larger than living platypus) but Teinolophos is tiny (under a dozen centimetres--the dwarf among platypus) judging from the jaw fragment that has been found (Rowe et al. 2008). Despite its diminutive size, Teinolophos is considered a platypus based on the similarities of its teeth (Springer et Krajewski 2009) and features of the jaw which indicate a hearing structure similar to living platypus (Rich et al. 2001). A hypothetical bill (indicated by grooves on the jaw) is also postulated. Because all three are known from such scrappy remains, I have placed a question mark by their branch. 

Obdurodon dicksoni from a dorsal view. The skull is
complete enough to be confident that this is of the
platypus kind.

All four of the above addressed species are known from dinosaur dominated habitats (Eumeralla Formation, Griman Creek Formation, etc). All are controversial, especially Kollikodon and Teinolophos which may turn out to be something totally different from platypus all together. Obdurodon fossils, however, bear more similarity to modern platypus than the previous four. In particular, O. dicksoni is known for a well preserved complete specimen (UCMP). There is no doubt that this animal was of the same created kind as the platypus. There were, however, a few differences, mainly involving the skull. The side of the head had a boney process whereas, in modern platypus, this region is flattened. The other two species of Obdurodon are distinguished by locality and small differences. O. subamericanum--formerly Monotrematum subamericanum--is known from a tooth found in South America (Archer et al. 1999). I've placed this species in the same genus as Obdurodon because of the extreme similarity of the teeth (Pascual et al. 2002). O. insignis is from partial skeletons and skulls in the Etudunna Formation of Australia while O. dicksoni is from the Namba Formation (Archer et al. 1999). O. dicksoni is known only from a skull and other cranial elements (Australian Museum).

The most notable feature that is traceable throughout the family tree of the platypus is its teeth. As was noted, the genetic variability of platypus teeth can be seen in the fluctuating number of roots on the molars. More striking however, is that, while Odurodon retained its teeth into adulthood, modern platypus loose their teeth as adults (UCMP). I wonder if Noah knew what he was doing when he took a degenerate platypus on the ark... Just kidding. More likely the platypus started loosing its teeth sometime in the early Ice Age. Now horny plates have replaced them as extensions of the bone (without teeth, natural selection ensured that the platypus had something to chew with).

Ornithorhynchus anatinus (the modern platypus) has fossils dated by evolutionists in both the Pleistocene and Pliocene (Archer et al. 1999). Both fossils are likely post-Flood because of the striking similarity to modern Australian fauna (Flannery et. Archer 1984). Because only skulls are known of this species, all comparisons in the tree are derived from features there. It is a testament against evolution that a platypus should loose its teeth through time, rather than gaining better ones. The strange platypus is indeed a poor story, but genetic variability sustains it today. 

References:

Archer, Michael, Rick Arena, Mina Bassarova, Karen Black, Jenni Brammall, Bernard Cooke, phil Creaser, Kirsten Crosby, Anna Gillespie, Henk Godthelp, Miranda Gott, Suzanne J. Hand, Benjamin Kear, Alan Krikmann, Brian Mackness, Jeanette Muirhead, Anne Musser, Troy Myers, Neville Pledge, Yuanqing Wang, and Steven Wroe. 1999. "The Evolutionary History and Diversity of Australian Mammals". Australian Mammology. 21: 1-45. http://www.create.unsw.edu.au/research/files/Archer%20et%20al%20%281999%29%20The%20evolutionary%20history%20of%20Australian%20m.PDF.

Australian Museum. "Animal Species: Obdurodon dicksoni". http://australianmuseum.net.au/Obdurodon-dicksoni. Accessed December 28, 2012.

Australian Museum. "Animal Species: Platypus". http://australianmuseum.net.au/Platypus. Accessed December 28, 2012.

Flannery, T. F. and M. Archer. 1984. "Macropodoids (Marsupiala) of the Early Pliocene Bow Local Fauna, Central Eastern New south Wales". Australian Zoologist. 21: 357-383. http://biostor.org/cache/pdf/9a/9d/45/9a9d456477e3a72d19ef76227ccd71bf.pdf.

Pascual, Rosendo, Francisco J. Goin, Lucia Balarino, and Daniel E. Udrizar Sauthier. 2002. "New Data on the Palaeocene Monotreme Monotrematum subamericanum, and the Convergent Evolution of Triangulate Molars." Acta Palaeontologica Polonica. 47(3): 487-492. http://www.app.pan.pl/archive/published/app47/app47-487.pdf. 

Phillips, Matthew J., T. H. Bennet, and Michael S. Y. Lee. January, 2010. "Reply to Camens: How Recently Did Modern Monotremes Diversify?". Proceedings of the National Academy of Sciences of the United States of America. Vol. 107. No. 4. http://www.pnas.org/content/107/4/E13.full.

Pridmore, Peter A., Thomas H. Rich, Pat Vickers-Rich, and Petr B. Gambaryan . December, 2005. "A Tchyglossid-Like Humerus from the Early Cretaceous of South-Eastern Australia". Journal of Mammalian Evolution. Vol. 12. Nos. 3/4. http://link.springer.com/article/10.1007/s10914-005-6959-9.

Rich, Thomas H., Patricia Vickers-Rich, Peter Trusler, Timothy F. Flannery, Richard Cifelli, Andrew Constantine, Lesley Kool, and Nicholas Van Klaveren. 2001. "Monotreme Nature of the Early Cretaceous mammal Teinolophos". Acta Palaeontologica Polonica. Vol. 46, No. 1, pp 113-118. http://app.pan.pl/archive/published/app46/app46-113.pdf.

Rowe, Timothy, Thomas H. Rich, Patricia Vickers-Rich, Mark Springer, and Michael O. Woodburne. "The Oldest Platypus and Its Bearing on Divergence Timing of the Platypus and Echidna Clans". Proceedings of the National Academy of Sciences of the United States of America. Vol. 105. No. 4. 1238-1242. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234122/.

Springer, Mark S. and Carey W. Krajewski. Editors: Hedges, S. Blair and Sudhir Kumar. 2009. "Monotremes (Prototheria)." The Timetree of Life. Oxford University Press. New York. http://books.google.ca/books?id=9rt1c1hl49MC&pg=PA463&lpg=PA463&dq=Zaglossus+robustus+age&source=bl&ots=PT3IQehtvl&sig=8DV2jpHgLmCXhWRVBb5_yMZnsQA&hl=en&sa=X&ei=qMjYUNuYN4zuigLg8YGQBQ&ved=0CEkQ6AEwBA#v=onepage&q=Zaglossus%20robustus%20age&f=false.

UCMP (University of California Museum of Paleontology). "Monotremata: Fossil Record". http://www.ucmp.berkeley.edu/mammal/monotremefr.html. Accessed December 28, 2012.