Fig 1.
Location map of the study area in northeastern Italy with indication of the localities that yielded thalattosuchian remains from the Middle-Upper Jurassic Rosso Ammonitico Veronese.
Numeration is arbitrarily started from the left; it does not match the order of discovery. 1) S. Ambrogio di Valpolicella (Verona province), possible source locality of the Neptunidraco ammoniticus holotype. 2) Tresché Conca (Vicenza province), source locality of MGP-PD 26552. 3) Cesuna (Vicenza province), source locality of MGP-PD 6572 and MGP-PD 6761. 4) Cima del Porco (Asiago, Vicenza province), source locality of MGP-PD 32438. 5) Unknown source locality of MM 25.5.1078 in the Asiago area. 6) Sasso d’Asiago (Vicenza province) source locality of FMCR SP3839. 7) Sasso d’Asiago (Vicenza province), possible source locality of MCLSC T2. 8) Ponte Serra (Belluno province), source locality of MGP-PD 27566. Map modified and reprinted from [50] under a CC BY license, with permission from Bollettino della Società Paleontologica Italiana, original copyright year 1981.
Fig 2.
(A) Idealized stratigraphy of the Rosso Ammonitico Veronese (RAV) in the Trento Plateau (Verona area and Asiago Plateau), and (B) the Middle-Upper Jurassic stratigraphic succession of Ponte Serra (Belluno) with inferred stratigraphic position of each crocodylomorph specimen so far recovered in the RAV and herein discussed. Silhouettes: a) Teleosauroidea (CC BY 3.0 Gareth Monger); b) Metriorhynchoidea (CC BY 3.0 Gareth Monger); c) Metriorhynchidae (CC BY 3.0 Mette Aumala). Lithostratigraphic and lithologic legend: 1) Hettangian-Domerian shallow-water limestones of the Calcari Grigi Group (Asiago Plateau); 2) Toarcian-Aalenian oolithic limestones of the San Vigilio Oolite (Lessini Mountains); 3) pseudonodular and 4) bioclastic limestones of the Bajocian p.p.-Callovian p.p. Rosso Ammonitico Inferiore (RAI); 5) well bedded cherty limestones (Callovian p.p.-Oxfordian p.p. Rosso Ammonitico Medio, RAM and Bathonian p.p.-Kimmeridgian p.p. Fonzaso Formation); 6) nodular limestones of the Kimmeridgian p.p.-Tithonian Rosso Ammonitico Superiore (RAS); 7) micritic cherty limestones of the Lower Cretaceous Maiolica; 8) oolitic and peloidal grainstones/packstones; 9) synsedimentary breccia. Compiled based on various sources [34, 47, 51].
Table 1.
Review of all thalattosuchians so far described from the RAV.
Fig 3.
Overview of MGP-PD 26552, “Steneosaurus” barettoni.
A) Orthogonal picture of the specimen. B) Anatomical drawing of the specimen with color-based differentiation of the main elements. Abbreviations: an, angular; dt, dentary; fr, frontal; int.b, infra-temporal bar, j, jugal; mx, maxilla; mx imp., maxillary imprint; na, nasal; pa, parietal; pmx, premaxilla; pmx imp., premaxillary imprint; prf, prefrontal; qu, quadrate; sa, surangular; soc, supraoccipital. Scale bars represent 10 cm.
Fig 4.
Surface analysis of MGP-PD 26552.
A) MGP-PD 26552 under ultraviolet radiation (UVA-UVC). Bright yellow shows the tooth enamel response, orange-red shows the cancellous bone response. B) Depth map of MGP-PD 26552 surface by means of photogrammetry. Warmer colors indicate more elevated regions. Scale bars represent 10 cm.
Fig 5.
A) Close-up of the premaxillary imprint with corresponding dislodged teeth. B) Detail of the occipital region of the skull. C) Close-up of the best-preserved mandibular ramus showing 3D foramina. D) Close-up of a posterior tooth in labial view. E) Close-up of a posterior tooth in lingual view. Abbreviations: ca, carina; exo, exoccipital; fn, foramina, int.bar, intertemporal bar; nuc., nuchal crest; pa, parietal; qu, quadrate; soc, supraoccipital; Scale bars: A) 2 cm; B-C) 3 cm; D-E) 1 cm.
Fig 6.
A) MGP-PD 6572 in lateral view; B) MGP-PD 6572 in anterior view; C) MGP-PD 6761 in lateral view; D) MGP-PD 6761 in dorsal view; E) MGP-PD 6761 and MGP-PD 6572 in articulation; F) MGP-PD 6761 in anterior view and MGP-PD 6572 in posterior view highlighting the compatible matrix encrustation of the articular facets. Abbreviations: n.ch, neural canal; pl.na, plesiosaur neural arch. Scale bars represent: A-B) 2 cm; C-F) 3 cm.
Fig 7.
MGGC 8846/1UCC123a, holotype of Neptunidraco ammoniticus under ultraviolet light (UVA-UVB-UVC).
A) Overview of the specimen serial section. B) Close-up of maxillary teeth showing the light lue response light of dentine under UV and the orange-yellow enamel response found only in the replacement crowns inside the corresponding roots. C) Detail of the cervical sectioned cervical vertebrae. Scale bars represent A) 10 cm; B-C) 5 cm.
Fig 8.
A) Orthogonal picture of the specimen. B) Anatomical drawing of the specimen with color-based differentiation of the main elements. Abbreviations: nv.f, neurovascular foramen; II° pal. mx, secondary palate maxilla, T, tooth. See text for teeth numeration. Scale bars represent 5 cm.
Fig 9.
A) The specimen under ultraviolet radiation (UVA). The labels translate to “Ichthyosaur in marble—Posterior portion of the mouth—Malm Asiago, Vicenza—Found in Chiampo in 14/12/1966 by Father Aurelio Menin”. B) Detail of the eroded posterior portion of the upper dentigerous element. C) Teeth in longitudinal section from the upper dentigerous element. D) Cross section of the slab showing its thickness and the persistence of the bone-dental elements. E) Cross section of TY8 and its replacement. F) Cross section of (from the left) TY7 and TY6 and TY5 with corresponding replacement crowns/buds. Scale bars represent: A) 5 cm; B) 3 cm; E-F) 1 cm.
Fig 10.
A) Orthogonal picture of the specimen. B) Anatomical drawing of the specimen with color-based differentiation of the main elements. Abbreviations: an, angular; C, cervical vertebra; c.r, cervical rib; dt, dentary; fr, frontal; fp/pt, frontoparietal-parietal; LMR, left mandibular ramus; LTF, left temporal fenestra; na, nasal; oc, occipital condyle; po, postorbital; prf, prefrontal; qu, quadrate; RMR, right mandibular ramus; RTF, right temporal fenestra; sa, surangular; sp, splenial; V, vertebra. Scale bars represent 10 cm.
Fig 11.
A) Close-up of the skull roof and imprint. B) 3D rendition of the digitally flipped model of nasal/prefrontal imprints by means of photogrammetry. C) Skull roof elements under ultraviolet radiation (UVA-UVB-UVC). D) Close-up of the only tooth found with MGP-PD 32438. E) Close-up of the left mandibular ramus. Abbreviations: an, angular; eu.f, Eustachian foramen; fr, frontal; fr.f, frontal fossae; na.im, nasal imprint; n.rd, nasal 3D rendition; oc, occipital condyle; po, postorbital; prf.im, prefrontal imprint; prf.rd, prefrontal 3D rendition; sa, surangular; sp, splenial. Scale bars represent: A,B, E) 5 cm; D) 1 cm.
Fig 12.
A) Close-up of the cervical vertebrae of the specimen. B) Cervical vertebrae under ultraviolet radiation (UVA-UVC). C) Close-up of the atlas-axis complex. D) Cervical rib close-up. E) Isolated sixth vertebra and possible remnants of a seventh. Abbreviations: at, atlas; ax, axis, C, cervical vertebra; c.r, cervical rib; od, odontoid process; V, vertebra. Scale bars represent: A,B,E) 5 cm; C) 2 cm; D) 3 cm.
Fig 13.
A) Sectioned mandibular(?) ramus. B-C) sections of the same mandibular ramus according to Cau (2019). Scale bars represent 5 cm.
Fig 14.
A) Orthogonal picture of the specimen. B) Anatomical drawing with color-based differentiation of the elements. Abbreviations: cor, coracoid; f, femur; fi, fibula; lat.pr, lateral process; isc, ischium; p, pubis; t, tibia; r, rib; r.imp, rib imprint; V, vertebra. Scale bar represents 20 cm.
Fig 15.
A) Isolated anterior vertebrae and ribs. B) Close-up of V3. C) Close-up of two anterior centra (from the left) V9 and V8. D) Close up of two middle vertebrae (from the left) V17 and V16. E) Close-up of two posterior centra (from the left) V19 and V18. F) Isolated anterior ribs and rib imprint. G) Last three preserved posterior centra of MCLSC T2. H) Close-up of the last two centra V23 and V22 (from the left). Scale bars represent: A, F, G) 5 cm; B, C, D, E, H) 3 cm.
Fig 16.
MCLSC T2 appendicular details.
A) Putative coracoid and unidentified flat elements. B) Preserved pubis close-up. C) Femur and ischium close-up. D) Partially outcropping long elements close to the femur, possibly representing tibia and fibula. E) Unidentified isolated bone and imprint, possibly representing the other femur or pubis. Abbreviations: cor, coracoid; fe, femur; isc, ischium. Scale bars represent: A) 4 cm; B-E) 5 cm.