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Figure 4 in Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite

Figure 4. Left hemimandibles of Felidae showing differences in the development of the mandibular coronoid process. A, Panthera leo. B, Paramachairodus ogygia from Batallones-1. C, Smilodon fatalis from Rancho La Brea.

Figure 5 in Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite

Figure 5. Comparative views of the skull and mandible of two Smilodontini species. A, Paramachairodus ogygia. B, Megantereon cultridens (artwork by M. Antón).

Figure 8 in Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite

Figure 8. Composite reconstruction of the skull, mandible and cervical vertebrae of Paramachairodus ogygia, based on material of several individuals from Batallones-1, showing the inferred position of the main cranio-cervical muscles relevant to the canine shear-bite (artwork by M. Antón).

Figure 9 in Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite

Figure 9. Photographs of first to seventh cervical vertebrae (C1-C7) (anterior to left) in dorsal view. A, Paramachairodus ogygia from Batallones-1, respectively, B-4561, B-5407, B-744 (5), B-5458, B-5459, B-707 (12) and B-707 (12) (the latter have the same number); B, Panthera pardus, 1599.

FIG. 14 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 14. — Bayesian majority-rule consensus topology of the post-burnin sample of trees for selected taxa (eutherian outgroup and metatherian ingroup), including the thylacosmilid sparassodont Anachlysictis gracilis Goin, 1997, focus of this study. Posterior probability support values> 75% indicated in branches.

FIG. 16 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 16. — Sequential reconstruction of the skull of Anachlysictis gracilis Goin, 1997: A, modified skull with original mandible; B, smoothed skull after mirroring; C, skull with reconstructed eyes, masticatory muscles and a tongue; D, 3D model of a reconstructed head. Artist: Tatsuya Shinmura. Scale bar: 20 mm.

FIG. 11 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 11. — Anachlysictis gracilis Goin, 1997; VPPLT 1612, lower dentition. Left lower dentition in occlusal (A), labial (E) and lingual (F) views; and right lower dentition in occlusal (B), labial (C) and lingual (D) views. Scale bar: 20 mm.

FIG. 8 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 8. — Anachlysictis gracilis Goin, 1997; VPPLT 1612, posterior portion of the skull: A, detail of basicranium in ventral view; B, lineal draw of the basicranium in ventral view; C, occipital view of the skull. Abbreviations: Al, alisphenoid; Bo, basioccipital; Bs, basisphenoid; bjs, basijugular sulcus; cf, carotid foramen; Eo, exoccipital; fm, foramen magnum; fo, foramen ovale; gf, glenoid fossa; hf, hypoglossal foramina; ips, foramen for the inferior petrosal sinus; jf, jugular fossa; Ju, jugal; pap, paracondylar process of exoccipital; pgp, postglenoid process; prgp, preglenoid process of jugal; Pt, pterygoid; spht, sphenoidal tubercles (basilar tubercles); Sq, squamosal. Scale bar: 20 mm.

FIG. 5 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 5. — Anachlysictis gracilis Goin, 1997; VPPLT 1612, skull in ventral view (A) and lineal draw (B). Abbreviations: Al, alisphenoid; Bo, basioccipital; Bs, basisphenoid; Eo, exoccipital; gf, glenoid fossa; hf, hypoglossal foramina; inf, incisive foramen; Ju, jugal; mpf, minor palatine foramen; mpp, medial palatine process of premaxilla; Mx, maxilla; n, notch; p, pits; pafo, paracanine fossa; Pal, palatine; pgp, postglenoid process; Psph, presphenoid; Pt, pterygoid; Px, premaxilla; Sq, squamosal. Scale bar: 20 mm.

FIG. 3 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 3. — Anachlysictis gracilis Goin, 1997; UCMP 39705, posterior fragment of right mandibular ramus, in lateral (A), posterior (B) and medial (C) views. Scale bar: 10 mm.

FIG. 4 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 4. — Anachlysictis gracilis Goin, 1997; VPPLT 1612, skull in dorsal view (A) and lineal draw (B). Abbreviations: Ip, interparietal; Ju, jugal; La, lacrimal; Mx, maxilla; Na, nasal; Pa, parietal; Pal, palatine; pop, postorbital process; Px, premaxilla; smf, suprameatal foramen; Sq, squamosal. Scale bar: 20 mm.

FIG. 1 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 1. — Geographical setting of the study area, indicating the collection points of specimens referred to Anachlysictis gracilis Goin, 1997 and generalized stratigraphic position. 1, IGM locality 75 (specimen IGM 184247, holotype); 2, UCMP locality V4531 ("Cerro Gordo 2": specimen UCMP 39705); 3, VPPLT locality "Finca Tres Pasos" (specimen VPPLT-1612).

FIG. 15. — 3D in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 15. — 3D digital models of the skull of Anachlysictis gracilis Goin, 1997, based on the specimen VPPLT 1612. Original 3D scans of the skull in lateral (A) and anterior (B) views; modified retrodeformed skull with original unmodified mandible, in lateral (C) and anterior (D) views. Scale bar: 20 mm.

FIG. 13 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 13. — Consensus tree obtained from parsimony cladistic analysis under equal weights. Bremer supports (from 6411 trees, cut 0) indicated over branches; Bootstrap support values indicated below branches. Supports not given for Dasyuromorphia, as this node was constrained a priori (see text).

FIG. 10 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 10. — Anachlysictis gracilis Goin, 1997; VPPLT 1612, upper dentition. Right row in occlusal (A) and lingual (B) views; left side in occlusal (C) and lingual (D) views; and detail of the incisors area in occlusal view (E). Scale bars: 20 mm.

opencc-zeroJul 2022View details →

dryad36/100

Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction

<p>Sharks (Selachimorpha) are iconic marine predators that have survived multiple mass extinctions over geologic time. Their prolific fossil record is represented mainly by isolated shed teeth, which provide the basis for reconstructing deep time diversity changes affecting different selachimorph clades. By contrast, corresponding shifts in shark ecology, as measured through morphological disparity, have received comparatively limited analytical attention. Here, we use a geometric morphometric approach to comprehensively examine tooth morphologies in multiple shark lineages traversing the catastrophic end-Cretaceous mass extinction — this event terminated the Mesozoic Era 66 million years ago. Our results show that selachimorphs maintained virtually static levels of dental disparity in most of their constituent clades across the Cretaceous–Paleogene interval. Nevertheless, selective extinctions did impact apex predator species characterized by triangular blade-like teeth. This is particularly evident among lamniforms, which included the dominant Cretaceous anacoracids. Conversely, other groups, such as carcharhiniforms and orectolobiforms, experienced disparity modifications, while heterodontiforms, hexanchiforms, squaliforms, squatiniforms, and †synechodontiforms were not overtly affected. Finally, while some lamniform lineages disappeared, others underwent post-extinction disparity increases, especially odontaspidids, which are typified by narrow-cusped teeth adapted for feeding on fishes. Notably, this increase coincides with the early Paleogene radiation of teleosts as a possible prey source, and the geographic relocation of disparity sampling 'hotspots', perhaps indicating a regionally disjunct extinction recovery. Ultimately, our study reveals a complex morphological response to the end-Cretaceous mass extinction and highlights an event that influenced the evolution of modern sharks.</p>

opencc-by-4.0May 2006View details →

Figure 1 in Intraspecific morphological tooth variability and geographical distribution: Application to the Savi's vole, Microtus (Terricola) savii (Rodentia, Arvicolinae)

Figure 1. Map of Italy with populations by region (see text for names of localities).

opencc-by-4.0May 2006View details →

Figure 2 in Intraspecific morphological tooth variability and geographical distribution: Application to the Savi's vole, Microtus (Terricola) savii (Rodentia, Arvicolinae)

Figure 2. Morphometry of the first lower molar of Microtus (Terricola).

Figure 2 in Aspects of the functional morphology in the cranial and cervical skeleton of the sabre-toothed cat Paramachairodus ogygia (Kaup, 1832) (Felidae, Machairodontinae) from the Late Miocene of Spain: implications for the origins of the machairodont killing bite

Figure 2. Inferred areas of muscular attachment on the skull of Paramachairodus ogygia.

FIG. 17 in A sabre-tooth predator from the Neotropics: Cranial morphology of Anachlysictis gracilis Goin, 1997 (Metatheria, Thylacosmilidae), based on new specimens from La Venta (Middle Miocene, Colombia)

FIG. 17. — Reconstructed head of Anachlysictis gracilis Goin, 1997. Artist: Tatsuya Shinmura.