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|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Mammalia - Ungulata - Merycoidodontidae
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|C. B. Schultz and C. H. Falkenbach 1950||SKULL: Size medium, basal lengths ranging from 199 to 265 mm., widths from 111 to 161 mm.; mesocephalic to brachycephalic; high; supraoccipital wings widely spread and protruding posteriorly, notched on sides; supra- occipital wings not fan shaped as in Brachycrus, Merycochoerus, Ustatochoerus, Ticholeptus, and Merychyus (Metoreodon), similar to Phenacocoelus, but with less lateral spread; deep pit on each side of medial line in exoccipital above base of paroccipital process; sagittal crest moderately prominent, higher than in examples of Phenacocoelus; braincase inflated, narrow posteriorly; frontals moderately wide above orbits, laterally rounded as in Phenacocoelus, nasals moderately robust, with anterior retraction; supraorbital foramen with slight to moderately prominent groove extending anteriorly; orbit oblong vertically in outline; zygomatic arch moderately light; zygomatic arch with slight notch (or inward curve) on external surface below and posterior to orbit; malar moderately deep to deep below orbit with an angular pro- tuberance on anterior, inferior border (less prominent than in Submerycockoerus); lacrimal fossa large and deep (similar to ex- amples of Phenacocoelus); facial vacuity present (see following discussion); small depressed area above premolar region; pre- maxillae joined for short distance; occipital condyle of moderate size; paroccipital process wide at base with a marked tapering to a flattened tip; bulla inflated but semi-depressed (more so than in examples of Phenacocoelus, less so than in Pseudomesoreodon); postglenoid process moderately high and robust; posterior palate projecting posteriorly beyond M3 for a greater distance than in Phenacocoelus.
MANDIBLE: Moderately heavy; postsymphysis usually below Pa; ramus moderately shallow for height of skull, increasing gradually in depth from symphysis to point below Ma, with gradual downward and inward curve extending posteriorly from Ma; condyle set approximately at right angle to axis of dental series with slight downward in- ternal slope (latter not so great as in Phenacocoelus).
DENTITIONB:rachyodont to subhypsodont (slightly longer crowned than in examples of Phenacocoelus); external styles of superior molars moderately prominent, premolars slightly crowded; C/ and P1 large; P 1 and P 2 usually set at slight angle to alveolar border; pi_pa usually with anterior intermediate crest.
LIMBS:Moderately light, but less so than in Merychyus; approximately equal in length to, to longer than in, Phenacocoelus, and somewhat lighter.