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. 2019 Apr 12;235(1):15–33. doi: 10.1111/joa.12992

Figure 2.

Figure 2

Cranial anatomy and anatomical networks featuring the first evolutionary stage. (A) Skull and lower jaw of the primitive synapsid Varanosaurus in lateral (above), medial (below) and occipital (right) views (modified from Berman et al., 1995). (B) Anatomical network of the primitive synapsid Varanosaurus. (C) Skull and lower jaw of the early cynodont Procynosuchus in lateral (above), medial (below) and occipital (right) views (modified from Brink, 1961; Kemp, 1979; Allin & Hopson, 1992). (D) Anatomical network of the early cynodont Procynosuchus. The bones of evolutionary interest in this study have been drawn as follows: yellow for the dentary, red for angular/ectotympanic, light blue for pre‐articular/gonial, blue for articular/malleus, green for quadrate/incus, turquoise for stapes, pink for the rest of the post‐dentary bones (coronoids, splenial and surangular), orange for the ossified Meckel's cartilage (Figures 4 and 5), metallic blue for squamosal, purple for the otic bones (opisthotic, prootic and their bone fusions), and gray for the remaining cranial bones according to their module identity. Cranial bones in white have not been included in this study. In the anatomical networks, square nodes represent the middle ear bones, 3D spherical nodes (Figures 4 and 5) represent the ossified Meckel's cartilage, and the green areas represent the mandibular modules. Abbreviations: paired bones have been indicated in the nodes by ‘.r’ and ‘.l’ for the right and left sides, respectively; a = angular, ac = anterior coronoid, ar = articular, as = alisphenoid, BC = basicranium, bo = basioccipital, bs = basisphenoid, co = coronoid, d = dentary, ec = ectopterygoid, eo = exoccipital, ep = epipterygoid, go = gonial, in = incus, ip = interparietal, j = jugal, ma = malleus, mx = maxilla, oc = occipital, OMC = ossified Meckel's cartilage, op = opisthotic, os = orbitosphenoid, ot = periotic, p = parietal, pa = pre‐articular, pbs = parabasisphenoid, pc = posterior coronoid, pe = petrosal, pl = palatine, po = post‐orbital, pp = post‐parietal, pr = prootic, ps = pre‐sphenoid, pt = pterygoid, q = quadrate, qj = quadratojugal, s = stapes, sa = surangular, so = supraoccipital, sp = splenial, sph = sphenoid complex, sq = squamosal, st = supratemporal, t = tabular, te = temporal, ty = ectotympanic, z = zygomatic.