Seal ossification in the ancestral state reconstruction, described beneath. The patellar tendons of the above scanned squamates and three individual Sphenodon specimens have been ready for histological examination. These tendons exhibiting mineralisation (evident from the X-ray CT pictures) had been decalcified within a EDTA option for week, with all the endpoint confirmed by XMT scanning. Specimens have been embedded in wax and serially sectioned. The sections were then stained with regular Haematoxylin and eosin (H E) and Safranin OFast green. Complete preserved lizards and tuatara belonging to NHM London plus the University of Adelaide were radiographed with several settings for optimal bone visualisation (generally kV and s). Osteological specimens belonging to NHM London have been also examined and photographed. Specimen numbers 
are detailed in Supporting Info Information S. Collections of fossil Rhynchocephalia and stem Lepidosauria (non-lepidosaur lepidosauromorphs) and other Reptilia belonging to Museum fur Naturkunde (MfN) Berlin, Staatliches Museum fur Naturkunde (SMNS) Stuttgart, PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/17569665?dopt=Abstract All-natural History Museum London (NHMUK), and UMZC have been examined for proof of patellar mineralisation. Specimens are listed in Table S. For ancestral state reconstruction, we coded lepidosauromorph taxa determined by our personal collected data along with the literature; publications detailing patellar presence in squamate species have been a rich source of data in creating the character matrix (Camp, ; Haines,a; Mohamed, ; Maisano, a; order Hematoporphyrin (dihydrochloride) Conrad ; Jerez Tarazona, ; Jerez et al. ; Daza et al. ; Gauthier et al. ; Otero Hoyos,). Patellar character states have been coded such that `’ ossified patella absent, `’ ossified patella present, `’ polymorphic (variable withinbetween individuals), `’ unknown patellar state, ` not applicable (due to reduced or absent hindlimbs; e.g. snakes, dibamids). Exactly where conflicts existed among the published and observed data, we coded the patella as it appeared in our information, or as polymorphic or uncertain . Parsimony reconstruction was performed more than a composite tree built manually from the recent phylogenies of Reeder et al. and Pyron et al. in MESQUITE application (Maddison Maddison,). We also explored the sensitivity of our reconstructions to tree topology working with an option morphology-based phylogeny (Gauthier et al.) and to character state coding by observing the adjustments in trait eutionary history when unique character coding was utilised for ambiguous or polymorphic taxa. A note on anatomy: normally, the patellar tendon (Apigenol continuous together with the triceps tendon) in lepidosaurs is formed by contributions from the thigh muscle tissues M. femorotibialis externus and M. ambiens, with smaller sized contributions from M. femorotibialis internus, M. iliotibialis and fascia connecting for the reduced limb muscle tissues (S. Regnault J. R. Hutchinson, pers. obs). This can be similar for the state observed in birds (Regnault et al.) but using the increased part of M. ambiens (relative towards the predominance of the lateral head of your femorotibial muscle in birds) along with the weaker connection of decrease limb muscles. We’ve got observed grossly related connections in Crocodylia (with all the triceps tendon only, e.g. Allen et al.), so these connections in lepidosaurs may possibly be plesiomorphic for the broader clade Sauropsida.ResultsThe patella in Sphenodon (Rhynchocephalia)Four from the XMT-scanned tuatara within this study were discovered to possess a discrete region of patellar mineralisation in both hindlimbs. It was not clear irrespective of whether the.Seal ossification from the ancestral state reconstruction, described beneath. The patellar tendons of the above scanned squamates and 3 individual Sphenodon specimens had been ready for histological examination. These tendons exhibiting mineralisation (evident in the X-ray CT images) had been decalcified in a EDTA option for week, together with the endpoint confirmed by XMT scanning. Specimens had been embedded in wax and serially sectioned. The sections have been then stained with typical Haematoxylin and eosin (H E) and Safranin OFast green. Entire preserved lizards and tuatara belonging to NHM London plus the University of Adelaide were radiographed with several settings for optimal bone visualisation (commonly kV and s). Osteological specimens belonging to NHM London had been also examined and photographed. Specimen numbers are detailed in Supporting Info Information S. Collections of fossil Rhynchocephalia and stem Lepidosauria (non-lepidosaur lepidosauromorphs) and other Reptilia belonging to Museum fur Naturkunde (MfN) Berlin, Staatliches Museum fur Naturkunde (SMNS) Stuttgart, PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/17569665?dopt=Abstract All-natural History Museum London (NHMUK), and UMZC have been examined for evidence of patellar mineralisation. Specimens are listed in Table S. For ancestral state reconstruction, we coded lepidosauromorph taxa depending on our own collected information and the literature; publications detailing patellar presence in squamate species have been a wealthy supply of information in constructing the character matrix (Camp, ; Haines,a; Mohamed, ; Maisano, a; Conrad ; Jerez Tarazona, ; Jerez et al. ; Daza et al. ; Gauthier et al. ; Otero Hoyos,). Patellar character states had been coded such that `’ ossified patella absent, `’ ossified patella present, `’ polymorphic (variable withinbetween men and women), `’ unknown patellar state, ` not applicable (because of decreased or absent hindlimbs; e.g. snakes, dibamids). Where conflicts existed among the published and observed information, we coded the patella since it appeared in our data, or as polymorphic or uncertain . Parsimony reconstruction was performed over a composite tree built manually in the current phylogenies of Reeder et al. and Pyron et al. in MESQUITE software (Maddison Maddison,). We also explored the sensitivity of our reconstructions to tree topology making use of an option morphology-based phylogeny (Gauthier et al.) and to character state coding by observing the changes in trait eutionary history when diverse character coding was employed for ambiguous or polymorphic taxa. A note on anatomy: in general, the patellar tendon (continuous together with the triceps tendon) in lepidosaurs is formed by contributions from the thigh muscles M. femorotibialis externus and M. ambiens, with smaller sized contributions from M. femorotibialis internus, M. iliotibialis and fascia connecting to the decrease limb muscle tissues (S. Regnault J. R. Hutchinson, pers. obs). That is comparable towards the state observed in birds (Regnault et al.) but with all the enhanced role of M. ambiens (relative to the predominance of 
your lateral head in the femorotibial muscle in birds) along with the weaker connection of reduced limb muscles. We’ve got observed grossly related connections in Crocodylia (using the triceps tendon only, e.g. Allen et al.), so these connections in lepidosaurs may perhaps be plesiomorphic for the broader clade Sauropsida.ResultsThe patella in Sphenodon (Rhynchocephalia)4 from the XMT-scanned tuatara in this study have been found to possess a discrete area of patellar mineralisation in each hindlimbs. It was not clear whether the.