Fig. 3: Trends in proboscidean dental traits in relation to aridity.
From: Fluctuating climate and dietary innovation drove ratcheted evolution of proboscidean dental traits
a–d, Evolution of hypsodonty (a), number of lophs/lamellae (b), enamel thickness (mm) (c) and enamel plicae frequency (d) in East African Proboscidea 26–0 Ma. Symbols for species are as in Fig. 1; colours mark families or paraphyletic ‘gomphothere’ group (blue), with each icon representing one molar. Lines connect mean values of each taxonomic group per locality and are for visualization. e-f, Aridity proxies: mean ordinated hypsodonty values of proboscidean localities (locality symbols are as in Fig. 2) (e), aeolian dust accumulation data from cores 659 and 722 (f). g–i, Example photographs illustrating morphology and measurements of molars in lateral and occlusal views: crown width (W) and height (CH) (hypsodonty = CH/W) (g), loph/lamella (L) and loph distance (LD) (h), and enamel thickness (ET) and plicae (PL) (plicae frequency = number of plicae in 1 cm of enamel band) (i). Left, P. macinnesi (Amebelodontidae) m3, Maboko, Kenya (NHMUK-PV-M15541a). Right, P. recki recki (Elephantidae) M3, Kanjera, Kenya (NHMUK-PV-M15418, reversed). Photographs are not to scale. The photographs on the left (Protanancus) represent a more plesiomorphic elephantoid molar and those on the right (Palaeoloxodon) represent a derived elephant molar. HYP, hypsodonty. Specimens photographed at the Natural History Museum, London.
