TABLE 1. Tooth counts of relevant Tanystropheus specimens from Monte San Giorgio. Specimens assigned to the small morphotype are indicated by an asterisk. Abbreviations: ia, inapplicable; mx, maxilla; pmx, premaxilla.
| Pmx. tooth count |
Maxilla tooth count |
Mx. position first tricuspid |
How tricuspid | Dentary position first tricuspid | Pterygoid tooth count |
Palatine tooth count |
Vomer tooth count |
|
| PIMUZ T 2819 | 6 | ? | ia | ia | ia | 0 | ? | ? |
| PIMUZ T 2790 | 6 | 15 | ia | ia | ia | 0 | ? | 15 |
| PIMUZ T 2787 | ? | ? | ia | ia | ia | 0 | 0 | 12 |
| PIMUZ T 2792 (cast of SNSB-BSPG 1953 XV 2) | ? | ? | ia | ia | ? | ? | ? | 5 or 6 |
| PIMUZ T 2482* | 6? | ? | 7 | rather bulbous | 12? | ? | 5 | ? |
| PIMUZ T 2795* | ? | ? | ? | at least a bit | ? | around 12 | at least 3 | 7 |
| MSNM BES SC 265* | 6 | ? | 4 or 5 | distinctly | around 7th | ? | ? | present |
| MSNM BES SC 1018* | 6 | 15 | 1st to 3rd | distinctly | around 5th | 12 sensu Nosotti (2007) | at least 3 | at least 3 |
| PIMUZ T 2484* | ? | 15 | around 5th | distinctly | beyond 10th | around 13 | 6 | ? |
| PIMUZ T 2779* | ? | ? | ? | distinctly | ? | ? | ? | 10 |
| PIMUZ T 3901* | 6 | ? | 3 or 4 | distinctly | beyond 4th | ? | ? | ? |
| PIMUZ T 1277* | ? | ? | ? | distinctly | around 5th | ? | ? | ? |
TABLE 2. An overview of the morphological differences between the large and small morphotype identified among the Tanystropheus specimens from Monte San Giorgio.
| Large morphotype | Small morphotype | |
| Tricuspid marginal dentition | Absent | Present on the maxilla and dentary |
| Prenarial process of the premaxilla | Absent or incipient | Small but present |
| Postnarial process of the premaxilla | Absent | Long |
| Vomer | Wide with dentition on the outer margin | Narrow with a single straight tooth row |
| Pterygoid | Edentulous and wide anteriorly | Tooth bearing and tapering anteriorly |
| Palatine | Edentulous and plate-like | Tooth bearing and narrow |
| Parietal | Long anterolateral and posterolateral processes and narrow in between these processes | Wide with short anterolateral and posterolateral processes |
| Paroccipital process of the opisthotic | Long and slowly reduces in height distally | Very short and expanding distally |
| Distinct "keel" on the anterior end of the dentary | Present | Absent, dentary slightly downturned anteriorly |
| Dorsal vertebrae | Relatively short with high neural spine | Relatively long with low neural spine |
TABLE 3. The lengths of the maxilla, dentary tooth row, and premaxillary body of each relevant Tanystropheus specimen from Monte San Giorgio and the relative size of each specimen based on these measurements. Specimens assigned to the small morphotype are indicated by an asterisk. Abbreviations: ia, inapplicable.
| Maxilla length (in mm) |
Dentary length |
Premaxilla main body (in mm) |
Relative size maxilla (in %) |
Relative size dentary (in %) |
Relative size premaxilla (in %) |
Mean relative skull size estimate (in %) |
Femur length (in mm) |
Relative size femur (in %) |
|
| PIMUZ T 2819 | 74.6 | 113.83 | 35.6 | 100 | 100 | 100 | 100 | ? | ia |
| PIMUZ T 2790 | 46.2 | 81.52 | 34.13 | 61.93029 | 71.62 | 95.87079 | 76.47 | ? | ia |
| PIMUZ T 2787 | 43.8? | 71.65 | 30 | 58.71314 | 62.94 | 84.26966 | 68.64 | 148.03 | 100 |
| PIMUZ T 2792 (cast of SNSB-BSPG 1953 XV 2) | 40.87? | 57.93? | 16.04 | 54.78552 | 50.89? | 45.05618 | 50.24 | 106.25 | 71.78 |
| PIMUZ T 2482* | 27.2 | 35.58 | 11.83 | 36.46113 | 31.26 | 33.23034 | 33.65 | ? | ? |
| MSNM BES SC 265* | 24.9 | 33.8 | 11 | 33.37802 | 29.69 | 30.89888 | 31.32 | 71 | 47.91/48.84 |
| MSNM BES SC 1018* | 24.2 | 30.3 | 35.6 | 32.43968 | 31.27 | 26.96629 | 30.23 | 70.92/72.3 | 54.21 |
| PIMUZ T 2795* | ? | ? | 10.75 | ? | ? | 30.19663 | 30.19663 | 80.25 | 47.96 |
| PIMUZ T 1277* | ? | 34.04 | ? | ? | 29.9 | ? | 29.9 | ? | 56.45 |
| PIMUZ T 2484* | 23.55 | 32.44 | 10.47 | 31.56836 | 28.5 | 29.41011 | 29.83 | 57.89 | ? |
| PIMUZ T 2779* | ? | 30.88? | 9.07 | ? | 27.13? | 25.47753 | 26.3 | ? | 39.11 |
| PIMUZ T 3901* | 20.39 | 30.06 | 7.8 | 27.33244 | 26.41 | 21.91011 | 25.22 | 83.56 | ? |
TABLE 4. The measurements and ratios used to establish the relative size of the prenarial and postnarial processes of the premaxilla and the dentary keel of each relevant Tanystropheus specimen from Monte San Giorgio. Specimens assigned to the small morphotype are indicated by an asterisk. Abbreviations: de., dentary; ia, inapplicable; pmx., premaxilla; po. p., postnarial process; pre. p., prenarial process.
| Pmx. pre. p. length (in mm) |
Pmx. pre. p. length (in mm) |
Dentary keel height (in mm) |
Pmx. pre p./pmx. main body | Pmx. po. p./pmx. main body | De. keel/de. tooth margin | |
| PIMUZ T 2819 | ? | ia | 4.8 | ? | ia | 0.046602 |
| PIMUZ T 2790 | 3 | ia | 4.4 | 0.087899 | ia | 0.095238 |
| PIMUZ T 2787 | ia | 7 | 1.5? | ia | 0.233333 | 0.022422 |
| PIMUZ T 2792 (cast of SNSB-BSPG 1953 XV 2) | 0.94 | 5.1 | 3.83 | 0.058603 | 0.317955 | 0.075142 |
| PIMUZ T 2482* | 1.56? | 2.25 | ia | 0.131868 | 0.190194 | ia |
| PIMUZ T 2795* | 0.78? | ? | ? | 0.072558 | ? | ? |
| MSNM BES SC 265* | ? | ? | ia | ? | ? | ia |
| MSNM BES SC 1018* | 0.4 | 6.6 | ia | 0.041667 | 0.6875 | ia |
| PIMUZ T 2484* | 1.37 | 4.36 | ia | 0.13085 | 0.416428 | ia |
| PIMUZ T 2779* | 1.02 | 2.36 | ? | 0.112459 | 0.260198 | ? |
| PIMUZ T 3901* | ? | 5.1 | ia | ? | 0.653846 | ia |
| PIMUZ T 1277* | ? | ? | ia | ? | ? | ia |
