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Table 2 List of the five landmarks with the greatest variation across the cranium for all cetaceans, archaeocetes, odontocetes, mysticetes, and terrestrial artiodactyls

From: Wonky whales: the evolution of cranial asymmetry in cetaceans

Suborder Average asymmetry in the skull
(x̄ρ)
1st highest landmark of variation 2nd highest landmark of variation 3rd highest landmark of variation 4th highest landmark of variation 5th highest landmark of variation Specimen showing top 5 landmarks (red)
Landmark description ρland Landmark description ρland Landmark description ρland Landmark description ρland Landmark description ρland
All cetaceans 0.268 L74: Dorsal medial maxilla (suture with nasal and premaxilla) 0.010 L68: Posterior lateral corner of nasal 0.009 L71: Posterior dorsal premaxilla 0.009 L121: Posterior point of nasal 0.008 L67: Left anterior lateral nasal 0.007  
Archaeocetes 0.251 L72:
Anterior lateral ventral premaxilla
0.007 L69: Tip of rostrum, anterior dorsal side, anterior midline of tooth row 0.007 L70: Anterior dorsal premaxilla 0.007 L82: Jugal posterior ventral 0.006 L73: Anterior lateral ventral maxilla 0.006
Odontocetes 0.290 L74: Dorsal medial maxilla (suture with nasal and premaxilla) 0.013 L68: Posterior lateral corner of nasal 0.011 L71: Posterior dorsal premaxilla 0.010 L121: Posterior point of nasal 0.009 L67: Left anterior lateral nasal 0.009
Mysticetes 0.191 L78: Posterior ventral lateral most point of maxilla (near orbit) 0.005 L79: Posterior tooth row lateral maxilla 0.005 L72: Anterior lateral ventral premaxilla 0.005 L71: Posterior dorsal premaxilla 0.005 L122: Anterior medial frontal 0.005
Terrestrial artiodactyls 0.171 L83: Lateral posterior frontal (posterior lateral parietal suture) 0.006 L87: Anterior medial parietal 0.005 L97: Posterior lateral most point of the mandibular articular process 0.005 L80: Jugal anterior dorsal 0.005 L98: Lateral posterior squamosal (occipital suture) 0.004
  1. ρ is the radius value calculated as the Euclidean distance between the computer-mirrored landmark and the manually placed landmark. The larger the value for ρ, the more it is displaced, indicating asymmetry between the two sides of the cranium. x̄ρ is the average of the total radii (∑ρ) values across the skull for all the specimens in that group. x̄ρland is the average radii across all specimens in that group for that landmark. Each image shows the position of the five landmarks of greatest variation for each respective group. Skulls not to scale
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