University textbook, Vertebrate Paleontology, by Michael J Benton: a focused review

Marc Srour University of Bonn (2010) reported:
“For specific fields of palaeontology, there are specific textbooks that are never replaced: for example, Mike Benton’s Vertebrate Palaeontology (4th ed, 2014) is the standard for vertebrates.

Available online as a PDF, Benton 2005 (3rd edition)
came out five years after Peters 2000 moved pterosaurs away from archosaurs (using four previously published phylogenetic analyses, adding four taxa to each analysis).

Let’s focus on this one topic for today’s blogpost
because this topic sheds light on professional (academic) paleontology. Other topics will follow in later days.

Figure 1. Cladogram from Benton 2005, p. 139 showing his pet hypothesis matching Scleromochlus with pterosaurs five years after that was invalidated by adding taxa in Peters 2000.

Benton 1999a pushed for a pterosaur relationship with the bipedal crocodylomorph with tiny hands and only four toes, Scleromochlus (Figs. 1, 2). He was not the first to do so (see below).

Six years later, in his university textbook, ‘Vertebrate Paleontology’, Benton 2005 cited Benton 1999a (Fig. 1) in a cladogram, omitting taxa found by Peters 2000 that were closer to pterosaurs. Benton 2005 was a third edition. The first and second editions were published in 1990 and 1997. A fourth edition appeared in 2014 (2015).

Figure 2. Scleromochlus, a bipedal basal crocodylomorph, and Anurognathus, a Late Jurassic pterosaur to scale.

Benton’s 2005 mistake was followed by
Benton joining his student, Dave Hone, to create and publish a supertree of previously published analyses (Hone and Benton 2007, 2008), testing the results of Peters 2000 vs. Bennett 1996, who did not test taxa later proposed by Peters. When it turned out that Peters’ list of four taxa were going to nest closer to pterosaurs than Scleromochlus, Hone and Benton (2008) removed all traces of data from Peters 2000 and arrived at no clear answer for the origin or closest relatives of pterosaurs. Worse yet, and beyond all logic, Hone and Benton 2008 gave credit for both competing hypotheses to Bennett 1996. Worse yet, no one in academic circles found that odd or improper. No one called out Hone and Benton for their failure to observe standards.

Bennett 2012 did report that their inability to replicate Peters’ (2000) analysis of a modified Bennett (1996) data set was the result of seven coding errors in retyping Peters’ published data matrix plus two 9s treated as a distinct character state.” That’s all. Note that the title of Bennett 2012 is “The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined.” So Bennett also kept his blinders on, omitting lepidosaur taxa proposed in Peters 2000, 2007.

BTW, creating supertrees, as in Hone and Benton 2007, 2008 means you don’t have to actually look at the taxa, or photos of the taxa, or drawings of the taxa. You just have to add one trusted matrix to another and another and another, and not always precisely, as Bennett 2012 noted above. During their time together Benton’s student became Doctor Dave Hone having successfully followed Dr. Benton’s instructions. Thus, Dr. Hone became the first PhD to earn his degree by undiscovering something.

I never thought paleontology would be like this,
but this is real. Just check out the paper trail (citations below).

Getting back to the origin of pterosaurs
in Benton 2005 (p138): “During the Triassic the archosaurs radiated into several groups. There were some short-lived forms in the Early Triassic, before a major split in the archosaur clade took place. One line led to the crocodilians, and the other to the pterosaurs, dinosaurs and birds.”

Point 1: Archosaurs (crocs + dinos, by definition) radiated into only two groups: crocs and dinos. In Benton’s borrowed and abbreviated cladogram (Fig. 1) crocs nest with a long list of archosauriformes, which make them all archosaurs (by definition). This is a traditional and mythological topology not supported by the LRT, which uses specimens as taxa, not suprageneric taxa. Because this topology is found in Benton 2005, this is the topology that has been circulating at the university level for the past decade and a half. To get a good grade you have to follow Benton’s cladogram (Fig. 1).

Point 2: In the LRT pterosaurs are lepidosaurs, as far from dinosaurs as you can get.

“The current view (Gower and Wilkinson, 1996) is that the crocodilian lineage, the Crurotarsi, includes most of the Late Triassic archosaurs, whereas the dinosaur lineage, the Ornithodira (see p. 153), includes dinosaurs, pterosaurs and a number of basal forms (see cladogram).”

The current view” These views (= opinions) have been circulating around universities for far too long, largely due to professor Benton’s textbooks of the last thirty years. Based on the lepidosaur nesting of pterosaurs, the traditional clade ‘Ornithodira‘ is a junior synonym for Reptilia. ‘Ornithodira’ needs to die.

If this is what they are still teaching at the university level, leave and ask for your money back. You should not be paying for untested views in a science class. We’ve met this sort of professor before. Remember Dr. David Winkler, who confessed, What guides the preference is, can I teach it?” A cold, hard cladogram should be taught. Not the current view, or the ability to teach it.

When will someone of Mike Benton’s status create their own wide-gamut specimen-level cladogram instead of borrowing the work of others and circulating untested material? This is how consensus (= the current view) develops around myths and invalid opinions. In his youth, Sterling Nesbitt 2011 attempted this, but scoring errors galore were discovered and reported here and in linked blogposts. That study has been widely cited based on its adherence to the status quo, Benton’s university textbook.

Be careful. If your run your own tests and find a valid answer, you’ll be ignored or villified. As Professor S. Christopher Bennett once said to me, “You will not be published, and if you are published, you will not be cited.” A little discouraging coming from a teacher. So be strong.

Getting back to the origin of pterosaurs
in Benton 2005 (p153): “The closest major outgroup of the dinosaurs may be the pterosaurs.

Note the weasel word, ‘may’. Benton (2005) knew this was invalidated four times five years earlier (in Peters 2000), but he chose to ignore that citation. No one in his profession noticed and paleo students around the world kept buying his textbook and cladogram (Fig. 1) at their professors’ instruction.

This may seem an unusual pairing, but Gauthier (1986) noted similarities between the two groups, particularly in the hindlimb.

Unusual pairing? evolution and wide-gamut cladograms, like the LRT, don’t produce “unusual pairings”. All sister taxa look alike. That’s how evolution works, in small changes.

Note the way Benton shifts the blame to Gauthier and Pulls a Larry Martin: the feint to the hind limbs (see below for the specific characters). There is no mention of the traits that make a pterosaur a pterosaur (also see below).

For example, the ankle joint is simplified to a hinge-like arrangement in which the astragalus and calcaneum act together as a kind of ‘roller’, and the middle three toes are elongated and held in an upright position so that the animal stands up on its toes, the digitigrade posture.”

An ankle joint. This is an example of convergence and Pulling a Larry Martin.

The middle three toes elongated and held digitigrade. Another attempt to Pull a Larry Martin. Benton 2005 fails to mention that digit 4 is longer than digit 3, as in lepidosaurs, not archosaurs. Benton 2005 also fails to mention that most pterosaur pes tracks are plantigrade.

There is no mention of Cosesaurus, Sharovipteryx and Longisquama as pterosaur relatives (Peters 2000) in Benton 2005, nor is Peters 2000 cited. In your own journey through paleontology, don’t ‘Pull a Michael Benton’. Never omit published taxa competing for a relationship to another taxon. Find the last common ancestor. Keep adding taxa until you find that last common ancestor.

“Scleromochlus has sometimes been allied with Pterosauria (Sereno, 1991), but it appears more firmly located in the phylogeny at the base of Avemetatarsalia (Benton, 1999a). This slender little reptile was only 170mm long, the size of a blackbird, and it was certainly bipedal—its forelimbs are very much shorter than its hindlimbs. It had been interpreted as a a climber or even a glider and hence in some way ancestral to pterosaurs.”

Note the way Benton once again credits (= deflects to) others, in this case Sereno (1991) for suggesting a relationship between Scleromochlus and pterosaurs, when Benton himself (1999a) wrote a complete paper about it. Note that all Benton 2005 asks of Scleromochlus is to be a climber or even a glider in order for it to be ‘in some way ancestral to pterosaurs.’ You can’t get more wishy-washy than this.

Every professor should have at hand a valid cladogram so he/she can state relationships with authority and clarity. It’s as important to vertebrate paleonotogy as Mendeleev’s periodic table of elements is to chemistry and astronomy. That’s what the LRT provides for free, online. If you’re really interested in paleontology, create your own cladogram. It’s a powerful tool you can use with authority for the rest of your life.

Today, the Benton 2005 hypothesis of pterosaur, dinosaur and Scleromochlus relationships (Fig. 1) is supported by Darren Naish, Mark Witton, Kevin Padian, Fabio Dalla Vecchia, Chris Bennett and a long list other pterosaur experts with PhDs. Unwin 2003 and Kellner 2003 set the tone as they were the first to omit the taxa in Peters 2000 when constructing their flawed (due to taxon exclusion) pterosaur cladograms.

By contrast,
the LRT has been firm from the start that pterosaurs nest within Lepidosauria (Peters 2007), far from dinosaurs. Adding over a thousand taxa in the last ten years has not moved them. Pterosaur outgroup taxa (Fig. 5) closely approximate the pterosaur bauplan documenting a gradual accumulation of derived traits. The most comprehensive pterosaur cladogram online is found here.

Figure 3. From Benton 2005, after Wild 1978, Compare to what is known of Eudimorphodon in figure 4. Note the foreliimbs are longer than half the torso here, but not in the actual specimen. And why are the hind limbs just dangling? They should be held laterally, like Draco and Sharovipteryx, two lepidosaurs that knew/know how to glide.

Getting back to the origin of pterosaurs
in Benton 2005 (pp224-239),

“The first pterosaurs from the Late Triassic, such as Eudimorphodon [Figs. 3, 4] from northern Italy (Wild, 1978), show all the unique characters of the group: the short body,
[not short, see Fig. 4]

the reduced and fused hip bones,
[not reduced, the ilium is elongated in all pterosaurs, but in the most primitive pterosaur, Begamodactylus (Fig. 5) the pelvis is larger than in related taxa],

the five long toes (including a divergent toe 5)
[Scleromochlus (Fig. 2) lacks toe 5, while Cosesaurus (Fig. 5) has a ‘divergent’ toe 5],

the long neck,
[Scleromochlus has a short neck while Cosesaurus has an appropriately long neck]

the large head with pointed jaws
[Scleromochlus has a wide flat head, but Eudimorphodon has a narrow, tall head, like Cosesaurus]

and the arm.
[no description provided by Benton, it just stops there].

The hand has three short grasping fingers with deep claws and an elongate fourth finger that supports the wing membrane.”
[Scleromochlus has vestigial fingers, including the fourth finger (Fig. 2) while Cosesaurus has long, robust fingers and digit 4 is the longest].

Figure 4. Lateral, dorsal and cross-sectional views of Eudimorphodon ranzii. Note the overlap of the posterior ribs over the hind limbs and the very wide torso. The cross section shows the 2nd dorsal ribs and the 23rd. Note the small ischium which could only produce small eggs. A little taller and wider than we thought before. The forelimbs are pretty short relative to the torso.
Figure 4. Lateral, dorsal and cross-sectional views of Eudimorphodon ranzii. Note the overlap of the posterior ribs over the hind limbs and the very wide torso. The cross section shows the 2nd dorsal ribs and the 23rd. The forelimbs are pretty short relative to the torso.

If this is what they are still teaching at the university level,
leave and ask for your money back. Benton 2005 knew he was omitting pertinent taxa and citations. Now that stain will always be part of his biography.

If you want a real education,
look at the fossils. Trace the fossils. Build an accurate reconstruction (Fig. 4). Build a cladogram. Don’t borrow someone else’s reconstruction (Fig. 3) or cladogram, if at all possible if you have a focused study.

Nowhere in his study of Scleromochlus
did Benton 1999a provide a diagram or tracing or photo of any pterosaur. A side-by-side comparison (Fig. 2) should have invited the same sort of criticism presented here because pterosaurs and archosaurs are not related to one another.

However, in this scratch my back, I’ll scratch yours world
where taxa can be omitted without penalty, maybe PhDs can do whatever they want to without penalty. Why is this so? They depend on the good will of one another during the review process. That’s why authors provide a list of preferred and not preferred referees during the submission process.

Benton 2005 is not the only case, of course.
Taxon exclusion is widespread. It continues to be the number one problem in vertebrate paleontology. That’s why the LRT and LPT are here: to minimize taxon exclusion.

Figure 1. Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown.
Figure 5. Bergamodactylus compared to Cosesaurus. Hypothetical hatchling also shown. Those long hind limbs are similar to the related Sharovipteryx.

For those interested in
the fenestrasaur and lepidosaur ancestry of pterosaurs (Peters 2000, 2007; Fig. 5), see the citations and links below.

If by some slim chance Benton 2014 (4th edition) turned around and gave credit
to Peters 2000 for the fenestrasaur ancestry of pterosaurs, let me know. I’ll grant that anything is possible, but if so I certainly would have heard about it by now. News of miracles travels fast.

Late addition, same day:
The pertinent cladogram from Benton 2014 (Fig. 6) shows Scleromochlus still close to pterosaurs and, closer to phytosaurs than to crocodylomorphs. Very strange. Once again, there are no taxa between pterosaurs and phytosaurs or between pterosaurs and Scleromochlus (Fig. 2). Colleagues. Proofread your cladograms before they get published. If something doesn’t look right, add taxa like Peters (2000) did. Don’t let an amateur point out your oversights and omissions.

Figure 6. From Benton 2014. Yellow color added here.

From now on, don’t judge your professors
by their degrees, by their affiliations, by their grants, by their textbooks, or by their students. Judge them by their history of doing the work that needs to be done, not borrowing from and trusting others, nor omitting pertinent taxa and citations to advance their own pet hypotheses and textbooks. Don’t let a paper trail like this follow you for the rest of your days in paleontology. Injustice and shenanigans will always be exposed.

Bennett SC 1996. The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoolological Journal of the Linnean Society 118: 261–308.
Bennett SC 2012. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology. iFirst article, 2012, 1–19.
Benton MJ 1999a. Scleromochlus taylori and the origin of dinosaurs and pterosaurs. Philosophical Transactions of the Royal Society, Series B,354, 1423–46.
Benton MJ 2005. Vertebrate Paleontology 3rd Edition PDF online Wiley-Blackwell 455 pp.
Benton MJ 2014. Vertebrate Paleontology 4th Edition Wiley-Blackwell 480 pp.
Carroll RL 1988. Vertebrate Paleontology and Evolution. WH Freeman and Co. New York.
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008 (2009). 
Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Kellner AWA 2003. Pterosaur phylogeny and comments on the evolutionary history of the group; pp. 105–137 in: E. Buffetaut and J. M. Mazin  (eds) Evolution and palaeobiology of pterosaurs: Geological Society Special Publications 217.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Sereno P 1991. Basal archosaurs: phylogenetic relationships and functional implicatons. Journal of Vertebrate Paleontology 11(supp004):1–53.
Unwin DM 2003. On the phylogeny and evolutionary history of pterosaurs; pp. 139–190 in: E. Buffetaut and J. M. Mazin (eds) Evolution and Palaeobiology of Pterosaurs. Geological Society Special Publications 217: 139–190.

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