Figure 1.
Mandibular types defined by Tullberg [7] in ventral view.
A, sciurognathous jaw; B, hystricognathous jaw. The angular process is coloured in red.
Figure 2.
A phylogenetic tree of the rodent clade Ctenohystrica derived from molecular analyses [13], [66].
Note the position of the clade ctenodactylids-Laonastes as the sister group of Hystricognathi. Red, Ctenohystrica; blue, mouse relative clade; green, sciurid relative clade. Dashed lines highlight the sample composition. Original artwork by Laurence Meslin, © Laurence Meslin – CNRS.
Figure 3.
Landmarks digitized on the mandible.
A, lateral view; B, anterior view.
Figure 4.
Morphological variation of the mandible among Ctenohystrica.
A, ventral view; B, lateral view. Colors indicate the relative amount of change in local area that was necessary to attain that shape, with the reference being the consensus shape. Yellow and violet code for an increase and decrease in surface area, respectively, and white indicates isometry. Scale unit: local area/same local area of the reference shape. On a ventral view, the yellow color will code for the lateralization of the angular process and thus hystricognathy whereas violet will characterize the sciurognathous condition.
Figure 5.
Phenetic trees based on mandible shape.
A, tree reflecting simple morphological affinities between Ctenohystrica families; B, size-corrected mandibular shape. Note the position of Caviidae close to Ctenodactylidae (i.e. sciurognathous rodents) in the second tree.
Figure 6.
Canonical variate analyses and associate patterns of morphological transformation for the mandible.
A, diet; B, habitat. Symbols indicate different clades: open stars, Diatomyidae; bars; Petromuridae; open circles, Thryonomyidae; crosses, Hystricidae; open triangles, Octodontoidea; open diamonds, Cavioidea; open squares, Chinchilloidea; trifid crosses, Erethizontoidea; “plus” symbol, Ctenodactylidae. Yellow and violet colors of the osteological features, same legend as Figure 4.
Figure 7.
Ventral view of the skull and the mandible in rodents of the “Cavioid” type (A), in Laonastes (B), and in rodents of the octodontoid type (C).
Black arrows show the origin and insertion of the superficial portion of the masseter muscle. Dashed arrows represent the internal pterygoid muscle. Red arrows express the direction of mastication. Yellow and violet colors of the osteological features, same legend as Figure 4.