Fig 1.
Geographical setting of the Ajoie district (NW Switzerland) and the three Late Jurassic tracksites along Highway A16 (‘Transjurane’).
Inset shows location within Switzerland. Numbers indicate the different tracksites: 1. Courtedoux—Béchat Bovais (CTD–BEB), 2. Courtedoux—Bois de Sylleux (CDT–BSY), 3. Courtedoux—Tchâfouè (CTD–TCH), 4. Chevenez—Combe Ronde (CHE–CRO), 5. Courtedoux—Sur Combe Ronde (CTD–SCR), 6. Porrentruy—CPP (POR–CPP).
Fig 2.
Chrono-, bio- and lithostratigraphic context of the Reuchenette Formation in the Ajoie district, Canton Jura, NW Switzerland (modified from [20,23,28,31].
Four track-bearing intervals, named lower, intermediate, and upper (dinosaur track) levels, and track levels 600 have been identified within the Courtedoux Member (Nerinean Limestones, sensu [32]). All studied material comes from the intermediate (levels 1000–1100) and upper (levels 1500–1650) dinosaur track levels, details shown on inset on the upper right.
Fig 3.
Methodology of track and trackway labeling and parameter measurements.
Note that the pictured tridactyl track does not correspond to Megalosauripus transjuranicus, it is a schematic track with a typical theropod phalangeal pad configuration of 2-3-4 for dII-III-IV, respectively. (A) Track length (PL) and width (PW), labeling of digits (d), phalangeal pads (P) and claws (C). The internal track outline corresponds to the (interpretation of the) actual impression of the foot. (B) Interdigital angles (da) and anterior triangle (AT). PW is the width and te the length (measured perpendicular to the width) of the anterior triangle, which in the present case has an obtuse angle for the anterior apex indicating a low mesaxony. (C) Digit lengths (L) and widths (W). (D) Trackway parameters. Labeling of trackways always starts with L1; if L1 is missing R1 is the first number used. α is the rotation (in this case outward and thus a positive value) of the track (long axis) with respect to the next stride line. LP and RP are left and right pace, respectively; S is stride; WAP is width of the angulation pattern (measured perpendicular to the stride length; [20]), γ is pace angulation. The progression is a calculated value (with the Pythagoras’s theorem) and it indicates the forward movement of the trackmaker in the direction of the trackway during one footfall (pace) [20]. Progression is only half of the stride in the case of completely regular trackways. The reference point for the trackway parameter measurements is on the tip of the third digit (without the claw where preserved).
Fig 4.
Outline drawings of Megalosauripus transjuranicus footprints.
(A) TCH1030-T6-L1, holotype. (B) BSY1035-T6-L2, paratype. (C) BSY1040-T1-R1, paratype. (D) TCH1025-T2-L1, paratype. (E) TCH1030-T2-R2, paratype; (F)TCH1030-T2-L3, paratype. (G) TCH1030-T7-L2, paratype. (H) BSY1040-T1-L2. (I) BSY1040T1-R2. (J) BSY1040-T1-L3. (K) BSY1040-T9-R3. (L) TCH1015-T1-L2. (M) TCH1015-T1-R3. (N) TCH1030-T3-L1. (O) TCH1030-T2-R3.
Fig 5.
Holotype of Megalosauripus transjuranicus.
Specimen TCH1030-T6-L1 (MJSN-TCH006-1319). (A) Trackway representation. (B) Photo of the specimen. Scale 20 cm. (C) Interpretative outline drawing. (D) Contour-lines. Spacing 1 mm. (E) False-color depth map. Depth measured in mm.
Fig 6.
Paratype of Megalosauripus transjuranicus.
Specimen TCH1030-T7-L2 (MJSN-TCH006-1317). (A) Trackway representation. (B) Photo of the specimen. Scale 30 cm. (C) Interpretative outline drawing. (D) Contour-lines. Spacing 1 mm. (E) False-color depth map. Depth measured in mm.
Fig 7.
Paratype of Megalosauripus transjuranicus.
Specimen BSY1040-T1-R1 (MJSN-BSY008-339). (A) Trackway representation. (B) Photo of the specimen. Scale 30 cm. (C) Interpretative outline drawing. (D) Contour-lines. Spacing 1 mm. (E) False-color depth map. Depth measured in mm.
Fig 8.
Paratype of Megalosauripus transjuranicus.
Specimen TCH1025-T2-L1 (MJSN-TCH006-1329). (A) Trackway representation. (B) Photo of the specimen. Scale 20 cm. (C) Interpretative outline drawing. (D) Contour-lines. Spacing 1 mm. (E) False-color depth map. Depth measured in mm.
Fig 9.
Paratypes of Megalosauripus transjuranicus.
(A) Trackway representation. (B-E) Specimen TCH1030-T2-R2 (MJSN-TCH006-1087). (B) Photo of the specimen. Scale 30 cm. (C) Interpretative outline. (D) Contour lines. (E) False-color depth map. Depth measured in mm. (F-I) Specimen TCH1030-T2-L3 (MJSN-TCH006-1022). (F) Photo of the specimen. Scale 30 cm. (G) Interpretative outline. (H) Contour-lines. Spacing 1 mm. (I) False-color depth map. Depth measured in mm.
Fig 10.
Paratype of Megalosauripus transjuranicus.
Specimen BSY1035-T6-L2 (MJSN-BSY008-330). (A) Trackway representation. (B) Photo of the specimen. Scale 30 cm. (C) Interpretative outline drawing. (D) Contour-lines. Spacing 1 mm. (E) False-color depth map. Depth measured in mm.
Fig 11.
Outline drawings of selected large theropod ichnotaxa, all drawn to the same scale.
Left tracks are mirrored as right tracks. (A) Holotype of Megalosauripus transjurani (TCH1030-T6-L1, MJSN-TCH006-1319). (B) Asianopodus, redrawn from [90]. (C) Irenesauripus redrawn from [86]. (D) Tyrannosauripus pillmorei, redrawn from [93]. (E) Bellatoripes fredlundi, redrawn from [94]. (F) Bueckeburgichnus maximus, redrawn from [84]. (G) Euthynichnium lusitanicum, redrawn from [3]. (H) Iberosauripus grandis, redrawn from [85]. (I) Megalosauripus uzbekistanicus, redrawn from [6]. (J) Megalosauripus-like track, redrawn from [172]. (K) Megalosauripus-like track, redrawn from [19]. (L) Megalosauripus from Arizona, redrawn from [3]. (M) Megalosauripus from Utah, redrawn from [3]. (N) Megalosauripus-like track, from [96]. (O) Megalosauripus-like track, from [108]. (P) Boutakioutichnium atlasicus, redrawn from [81]. (Q) Holotype of Hispanosauropus, redrawn from [4]. (R) Megalosauropus broomensis, redrawn from [83]. (S) Megalosauripus teutonicus, redrawn from [76]. (T) Jurabrontes curtedulensis, holotype (SCR1500-T1-L8, MJSN-SCR011-553), from [98].
Fig 12.
Outline drawings of Megalosauripus cf. transjuranicus (A-H), Megalosauripus? transjuranicus (I-Q), and of Morphotype II (R-Y) tracks.
All tracks are drawn to the same scale. (A) SCR1000-T23-R1. (B) SCR1000-T23-L2. (C) SCR1000-T23-R2. (D) TCH1020-T1-R2. (E) TCH1020-T2-L1. (F) TCH1020-T2-R1. (G) TCH1020-T2-L2. (H) TCH1020-T2-R2. (I) TCH1000-TR1-R2. (J) TCH1000-TR1-L3. (K) TCH1000-TR1-R3. (L) TCH1000-TR2-R9. (M) TCH1000-TR2-L10. (N) TCH1000-TR2-R10. (O) TCH1000-TR2-L12. (P) TCH1000-TR2-R12. (Q) TCH1000-TR2-L13. (R) BEB500-TR7-L2. (S) BEB500-TR7-R2. (T) BEB500-TR7-R7. (U) BEB500-TR7-L10. (V) BEB500-TR7-R10. (W) BEB500-TR7-L11. (X) SCR1000-T18-R1. (Y) TCH1030-T1-R4.