Nothrotheriinae, PP

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 : 1529

Nothrotheriinae

PP = 100, age = 15.44 Mya (13.02–17.76).

The clade is composed of five genera consistently recovered in all analyses with the following arrangement: (( ‘ Xyophorus’, Mionothropus ), ( Pronothrotherium , ( Nothrotherium , Nothrotheriops ))).

Nothrotheriinae was supported by 24 synapomorphies (12 for both methods and 12 exclusively for BI): trapezoidal Mf2 and Mf3 crosssection (BI); absence of a corkscrew-like rotation in the plane of articulation of mandibular condyle, in dorsal view (BI); presence of angle at the junction of symphysis and lower edge of horizontal ramus of mandible in lateral view (BI); large supraoccipital exposure on cranial roof, expanded anteriorly at midline; posterior segments of temporal lines run anterior to but closely parallel the nuchal crest (BI); nasal expands posteriorly, lateral margins divergent (BI); lateral and medial palatal processes of maxilla of equivalent length; interpterygoid and posterior interpalatine regions of roughly equal width; presence of pterygoid/vomer contact (BI); large sinus in pterygoid; alisphenoid-parietal contact present (BI); external occipital protuberance ventral to dorsal nuchal crest, in line with ventral nuchal crest (BI); posterior edge of occipital condyles ends at or anterior to posterior edge of foramen magnum superior border; large exposure of vomer in nasopharynx, covers presphenoid and much of basisphenoid; pterygoid does not participate in bony wall of tympanic cavity; anteroventral process of tegmen tympani as a large bony mass; occipital artery passes through a short canal in mastoid, perforating paroccipital process; glenoid fossa well separated from porus acusticus (BI); anteriorly directed root of zygoma; humeral head widely exposed, raised above the tubercles (BI); proximolateral process of metacarpal II does not extensively overlap metacarpal III proximally, contacting magnum (BI); absence of a detached sulcus delimitating, both medially and laterally, the articular surface of the femoral head in anterior view (BI); absence of a strong concavity between greater trochanter and the head of femur; and femoral patellar trochlea isolated or only abuts the condylar surfaces.