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Trigonostylopoidea (disused)
Taxonomy
Trigonostylopoidea was named by Simpson (1934).
It was assigned to Astrapotheria by Simpson (1934); to Ungulata by Simpson (1967); and to Meridiungulata by McKenna (1975).
It was assigned to Astrapotheria by Simpson (1934); to Ungulata by Simpson (1967); and to Meridiungulata by McKenna (1975).
Synonymy list
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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.
Subor. †Trigonostylopoidea Simpson 1934
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| G. G. Simpson 1934 | xtinct South American ungulates of very isolated and doubtful position,butperhapsrelatedtotheAstrapotheria. Twopairsofone-lobedlower incisors. P1 present(vestigial)orabsent,PT-iIpresent. Tuskssomewhatlikethose oftrueastrapotheres,butalwaysrooted,relativelylow-crowned,andsmaller. Cheek teethbrachyodont. Uppermolarsusuallytriangular,metaconefoldpresentbutmay be very weak, protoloph continuous but feeble, hypocone rudimentary and excluded fromtrigon,notruemetaloph,nocrista,trigonbasinclosed,broad,shallow. Lower molars imperfectly lophiodont, anterior wing of trigonid poorly developed and short,endingatmidline,notalonidpillar. Infraorbitalforamenmultiple. Palate withposteriormedianprocess. Choanaedividedbybonypartition. Sagittalcrest verylongandpowerful,temporalcrestslittledeveloped. Auditoryregionbroadly expandedandwellexposed. Auditorynotchbroadandopen,post-tympanicprocess practicallyabsent. Tympanicnearlyhorizontal,attachedsuturally,thickandscale- like, not inflated, with deep notch beneath meatus and round carotid evagination on innerside. Mastoidexposedonocciput. Condylarforamenfarfromcondyleand opening into pit or gap between tympanic and basioccipital. |
Measurements
No measurements are available
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| Source: subc = subclass, c = class, subp = subphylum | |||||
| References: Ji et al. 2002, Carroll 1988, Lillegraven 1979, Hendy et al. 2009 | |||||
Collections
No collection or age range data are available