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Lü and Li 2006, a review

Bruno Campos was kind enough to send me a pdf of the recent paper by Lü and Li (2006), Preliminary Results of a Phylogenetic Analysis of the Pterosaurs from Western Liaoning and Surrounding Areas, J. Paleont. Soc. Korea 22: 239-261.

The aim of the paper was to explore the interrelationships of most Liaoning pterosaurs conducted using a modified character matrix of Kellner (2004). The matrix contained 80 characters and 56 taxa with 3 outgroup taxa (Ornithosuchus, Herrerasaurus and Scleromochlus).

1. Well, the choice of the outgroup taxa dooms the base of this study from the start. Pterosaurs are lizards, not archosaurs as shown by a cladistic analysis 2 to 14 times larger and more inclusive than any prior attempt at classifying amniotes.

2. 34,000 most parsimonious trees were found and that's because the limit of the Max Tree was set at 34,000. Wow. That should be a huge red flag that something is rotten in this tree and more work needs to be done.

3. As usual, the highly derived pterosaur, Rhamphorhynchus, is shown to be the sister group to the classic 'Pterodactyloidea' when anyone with an eyeball would be hard-pressed to find a synopomorphy or two uniting the two. In an unpublished cladistic analysis of greater breadth, Rhamporhynchus is a highly derived dead end leaving no progeny and the pterodactyloid grade arises four times by convergence from dorygnathids twice and via basal dorygnathids, from scaphognathids twice.

4. The clade containing Azhdarcho and Eopteranodon continues getting mixed up with the clade containing Quetzalcoatlus due the convergent presence of hyperelongated cervicals. This is also the source of the confusion regarding the putatitive relationship between Quetzalcoatlus and Tupuxuara.

5. No tiny pterosaurs (typically known from numbers rather than names) were included, which also screws up the results royally. Tracings of pterosaurs in eggs show that their proportions do not differ greatly from their parents, so any so-called assignments of short-rostrum 'juveniles' to long-rostrum 'adults' are false and misleading.

Bottom line: garbage in, garbage out. Pretty much a useless analysis that sheds little light on pterosaur relationships.

Pterosaur workers: Get rid of your gender bias! Use more Dorygnathus and Scaphognathus specimens. Use more characters. Otherwise you, too, will be stuck with 34,000 MPTs.


David Peters
St. Louis