Megalonychidae, Ameghino, 1889

Casali, Daniel M, Boscaini, Alberto, Gaudin, Timothy J & Perini, Fernando A, 2022, Reassessing the phylogeny and divergence times of sloths (Mammalia: Pilosa: Folivora), exploring alternative morphological partitioning and dating models, Zoological Journal of the Linnean Society 196 (4), pp. 1505-1551 : 1526

Megalonychidae

PP = 63, age = 20.88 Mya (18.61–23.61).

The position of Hapalops as a stem megalonychid was recovered in all BI analyses, but was poorly supported. The clade containing all other Megalonychidae will be detailed below.

Megalonychidae was supported by seven synapomorphies (one for both methods and six exclusively for BI): Cf1 closer to anterior edge of maxilla than to Mf1 (BI); maximum height of coronoid process greater than its anteroposterior length (BI); large supraoccipital exposure on cranial roof, expanded anteriorly at midline; triangular occiput in posterior view (BI); presence of paroccipital process foramen (BI); eustachian tube opening formed by entotympanic and ectotympanic (BI); and absence of a deep notch for medial cruciate (posterior) ligament in femur (BI).