Afrotheria: Paenungulata

Bifurcated styloglossus muscle (see also Fig. 1019); nails, rather than hooves; digits usually 4/3;

Small rodent or rabbit-like forms with some large extinct relatives. Short skull with short rostrum; dental formula 1/2, 0,0, 4/4, 3/3; upper incisors, widely separated, triangular, tusk-like & ever-growing, with enamel only on lingual face; lower incisors wedge-shaped & tricuspid; small diastema present; upper molars with ectoloph & 2 cross-lophs; lowers lilambdodont (?); deep lower jaw; orbital bar present; zygomatic arch complete; jugal large & contributes to glenoid; small auditory bullae; compact body; tail highly reduced; clavicle absent; digits 4(5?)/3, with flat nails ("hoof-like"?) except for claw on pes 2; mesaxonic (III); palm/sole covers metapodials with thick, elastic, glandular skin which can be cupped for traction; stomach simple, with 3 ceca; mainly herbivorous, with some omnivory; metabolism low & behavioral thermoregulation common; able climbing & jumping; fairly wide variety of guilds and ecological settings.

Large coastal marine herbivores. Skull short, with strongly developed premaxillary; dentition variable among species; primitively 5(!) premolars; essentially modern postcranium from earliest known remains of mEc age; nostrils valvular, extending posteriorly beyond anterior rim of orbit; nasals reduced or absent; dentary deep; rostrum and dentary deflected ventrally at anterior end; tympanic semi-circular; periotic not connected to skull (as in cetaceans); heavy pachostotic ribs; muscular tail with flukes; digits 5/0, with forelimb as flipper; strongly developed deltopectoral crest [T+01]; hindlimbs absent; pelvis vestigial; lungs unlobed, long, & oriented horizontally with a horizontal diaphragm (used for floatation); heavy, dense bone; large, mid-gut cecum; very slow metabolism and low-nutrient diet; metabolism & relatively poor insulation restrict range to warmer waters; complex oral signals; social behavior not well known.