Fig 1.
Thaichelys ruchae, shell fragments.
A–D, SM2017-1-124, part of the anterior left carapace margin in (A) dorsal, (B) posterior, (C) anterolateral (outer), and (D) ventral view. E–J, SM2017-1-124, left bridge region in (E) dorsal, (F) ventral, (G) lateral, (H) medial, (I) anterior, and (J) posterior view.
Fig 2.
Comparison of carapace morphology in Triassic turtles (left side, view approximately perpendicular to the supramarginal surface, anterior towards the left, scaled to roughly the same shell length).
A, Thaichelys ruchae SM2017-1-124. B, Proterochersis robusta SMNS 18440. C, Proterochersis porebensis ZPAL V. 39/48 (holotype). D, Proterochersis robusta SMNS 17561. E, Proganochelys quenstedtii MB.1910.45.2. F, Proganochelys quenstedtii SMNS 16980. G, Palaeochersis talampayensis PULR 068 (holotype).
Fig 3.
Thaichelys ruchae, carapace margin fragments.
A–F, MNHN.F.THA11, part of the presumed anterior left carapace margin in (A) dorsal, (B) anteromedial, (C) ventral, (D) outer (anterolateral), (E), posterolateral, and (F) basal (medial) view. G–L, MNHN.F.THA22.3 (cast of TF 1440-5c), carapace part from the left bridge region in (G) external (lateral), (H) anterior, (I) visceral (medial), (J) posterior, (K) dorsal, and (L) ventral view. M–Q, PRC 202, carapace part from the left bridge region in (M) external (lateral), (N) anterior, (O) visceral (medial), (P) dorsal, and (Q) ventral view. R–W, MNHN.F.THA14, carapace part from the right bridge region in (R) external (lateral), (S) anterior, (T) visceral (medial), (U) posterior, (V) dorsal, and (W) ventral view; X–C′, MNHN.F.THA13, carapace part from the left bridge region in (X) external (lateral), (Y) anterior, (Z) visceral (medial), (A′) posterior, (B′) dorsal, and (C′) ventral view; D′–I′, MNHN.F.THA15, carapace part from the right bridge region in (D′) external (lateral), (E′) anterior, (F′) visceral (medial), (G′) posterior, (H′) dorsal, and (I′) ventral view; J′, K′, PRC 197, part of the carapace periphery (views not determined).
Fig 4.
Thaichelys ruchae, carapace fragments.
A–D, SM2017-1-128, dorsomedial part of the carapace (side not determined) with a partial rib shaft in (A) external, (B, D), anterior or posterior, and (C), visceral side. E–J, carapace part with a pleural boss in (E) external, (F, J) anterior or posterior, (G) visceral, (H) dorsal, and (I) ventral view.
Fig 5.
F.THA22.1 (cast of TF-1440-5a), presumed anterolateral right part of the carapace. A–C, specimen in (A) external, (B) presumed lateral, and (C) visceral view. D, comparison [1]with the anterior part of the carapace of Proterochersis porebensis ZPAL V. 39/49 (paratype, left) in dorsal view. Scute sulci indicated with grey lines, dashed grey lines indicate poorly defined or ambiguous sulci. D not to scale.
Fig 6.
Thaichelys ruchae SM2015-1-001 (holotype), left side of the anterior plastral lobe.
A, dorsal view. B, ventral view. C, anterior view. D, posterolateral view. E, posterior view. F, lateral view. G, medial view.
Fig 7.
Thaichelys ruchae, partial anterior plastral lobes.
A–F, SM2017-1-129 (left) in (A) dorsal, (B) ventral, (C) anterior, (D) posterior, (E) lateral, and (F) medial view. G–L, MNHN.F.THA17 (left) in (G) dorsal, (H) ventral, (I) anterior, (J) posterior, (K) lateral, and (L) medial view. M–R, MNHN.F.THA21 (right) in (M) dorsal, (N) ventral, (O) anterior, (P) posterior, (Q) lateral, and (R) medial view. S–X, MNHN.F.THA18 (right) in (S) dorsal, (T) ventral, (U) anterior, (V) posterior, (W) lateral, and (X) medial view.
Fig 8.
Comparison of the gular region morphology in Triassic pantestudinates (ventral view, scaled to roughly the same shell length).
A, Thaichelys ruchae SM2015-1-001 (holotype, left side). B, Thaichelys ruchae SM2017-1-129 (left side, gular damaged). C, Thaichelys ruchae MNHN.F.THA17 (left side). D, Thaichelys ruchae MNHN.F.THA21 (right side, gular damaged). E, Proterochersis porebensis ZPAL V. 39/420 (left side). F, Proterochersis porebensis ZPAL V. 39/48 (holotype, both sides). G, Proterochersis porebensis ZPAL V. 39/49 (paratype, both sides, left extragular damaged). H, Proterochersis porebensis ZPAL V. 39/385 (both sides). I, Proterochersis robusta SMNS 17561 (both sides, right extragular restored). J, Keuperotesta limendorsa SMNS 17757 (part of the right extragular). K, Proganochelys quenstedtii SMNS 16980 (both sides). L, Proganochelys quenstedtii SMNS 17204 (both sides, deformed). M, Proganochelys quenstedtii SMNS 17203 (left side). N, Proganochelys quenstedtii SMNS 15759 (partial right epiplastron). O, Palaeochersis talampayensis PULR 068 (holotype, both sides). P, Odontochelys semitestacea IVPP V 13240 (paratype, both sides, right extragular somewhat dislocated, right extragular missing). E: extragular; G: gular; I: intergular; S: supernumerary scute.
Fig 9.
Comparison of the gular region morphology in Triassic pantestudinates (anterior, dorsal, posterodorsolateral left, and lateral left view, scaled to roughly the same shell length).
Proterochersis porebensis ZPAL V. 39/385 mirrored (left to right) in posterolateral view for easier comparison. DEP: dorsal epiplastral process. In lateral view, arrowhead marks the anterior direction and red dotted lines indicate the transition between the anterior, scute covered face of the gular and the dorsal epiplastral process.
Fig 10.
Comparison of the bridge region morphology in Triassic pantestudinates (ventral view, scaled to roughly the same shell length).
A, Thaichelys ruchae SM2017-1-124. B, Proterochersis robusta SMNS 18440. C, Proterochersis robusta SNBS 17561. D, Proterochersis porebensis ZPAL V. 39/49 (pratype). E, Proganochelys quenstedtii SMNS 17204. F, Proganochelys quenstedtii SMSN 16980. G, Proganochelys quenstedtii MB.1910.45.2. H, Palaeochersis talampayensis PULR 068 (holotype). Scute sulci in A indicated with grey lines, dashed lines indicate poorly defined or ambiguous sulci.
Fig 11.
Thaichelys ruchae, plastral fragments.
A–F, MNHN.F.THA12, fragment of the left hyoplastron in (A) visceral (dorsal), (B) external (ventral), (C) anterior, (D) posterior, (E) lateral, and (F) medial view. G–L, MNHN.F.THA20, probable left xiphiplastron in (G) visceral (dorsal), (H) external (ventral), (I) anterior, (J) posterior, (K) lateral, and (L) medial view.
Fig 12.
Thaichelys ruchae, forelimb bones.
A–F, MNHN.F.THA16, left humerus in (A), capitular, (B) intertubercular, (C) ulnar, (D) radial, (E) proximal, and (F) distal view. G, H, MNHN.F.THA19, (?right) radius, distal part in (G)?dorsal and (H)?ventral view.
Fig 13.
Thaichelys ruchae SM2017-1-130, partial left ilium.
A, lateral view. B, anterior view. C, medial view. D, posterior view. E, dorsal view. F, ventral view.
Fig 14.
Comparison of the ilium morphology in Triassic pantestudinates (scaled to roughly the same ilium length).
A, B, Thaichelys ruchae SM2017-1-130, partial left ilium in (A) lateral and (B) anterior view. C, D, Proterochersis porebensis ZPAL V. 39/177, partial left ilium in (C) lateral and (D) anterior view. E, F, Proterochersis robusta SMNS 56606, right ilium in (E) lateral and (F) anterior view. G, H, Proganochelys quenstedtii SMNS 16980, right ilium in (G) lateral and (H) anterior view. I, J, Palaeochersis talampayensis PULR 068 (holotype) in (I) lateral and (J) anterior view.
Fig 15.
Thaichelys ruchae, anatomically indeterminate material.
A–D, SM2017-1-126, shell fragment in (A) external, (B) visceral, and (C, D) edge views. E–H, SM2017-1-127, shell fragment in (E) external, (F) visceral, and (G, H) edge views; I, J, SM2017-1-135, shell fragment in (I) external and (J) visceral view. K, L, SM2017-1-131, appendicular bone shaft or part of the dorsal epiplastral process or dorsal scapular process. M, N, SM2017-1-136, appendicular bone shaft or part of the dorsal epiplastral process. O, P, SM2017-1-133, shell fragment. Q, R, SM2017-1-134, carapace periphery or plastron fragment. S, T, PRC 196, shell fragment in (S) external and (T) visceral view. U, V, PRC 198, shell fragment. W, X, PRC 199, probable fragment of two sutured costals or plastral bones in (W) external and (X) visceral view. Y, Z, PRC 200, shell fragment in (Y) external and (Z) visceral view. A′, B′, probable fragment of juvenile plastron. C′, D′, MNHN.F.THA10 polygonal plate (?part of carapacial dermal mosaic) in (C′) external and (D′) visceral view. E′–J′, MNHN.F.THA22.2 (cast of TF 1440-5b), shell (?carapace) fragment in (E′) external, (F′) visceral, and (G′, H′, I′, J′) edge view. Precise orientation of all specimens not determined.
Fig 16.
Strict (left) and Majority Rule (50%, right) consensus trees of the recovered phylogeny.
Bootstrap values above 50 indicated by the numbers in circles.
Fig 17.
SM2017-1-132, probable fragment of a neural arch. Precise orientation not determined.
Fig 18.
Thaichelys ruchae, life restoration as a proterochersid turtle.
Digital drawing by Sita Manitkoon.