Scapula Shape Index:
It's scapula width/length ratio.Higher score indicates greater muscle attachement (infraspinatus, supraspinatus, subscapuralis) on the shoulder joint as well as greater ability to make certain movements like full-functional upper extremity movement including protraction,retraction,elevation,depression,upward rotation,and downward rotation all else being equal.
P.Leo : 77%
M.Ursinus : 87%
Edge : M.Ursinus
API:
Acromion process length/scapula length. Higher score in this ratio increases attachment for
the deltoid muscle.
P.Leo : 8%
M.Ursinus: 21%
Edge : M.Ursinus
SMI:
Deltopectoral crest length divided by humerus length. Higher score Displays greater mechanical advantage of deltoid and pectoral muscles at the shoulder joint.
P.Leo : 62%
M.Ursinus : 65%
Edge : M.Ursinus
PFI:
Scapula length divided by Forelimb length(humerus + radius + metacarpal III). Higher score Indicates greater speed of movement via relative proportions of components of the proximal forelimb as well as exertion of greater force from the forelimb.
P.Leo : 34%
M.Ursinus : 36%
Edge : M.Ursinus
HRI :
It is humerus mediolateral diameter at mid-shaft/humerus length.Robust forelimb bones protect the animal from violent stresses during grappling.
P.Leo : 9%
M.Ursinus : 10%
Edge : M.Ursinus
HRI2 :
It is humerus anteroposterior diameter at mid-shaft/humerus length. Robust forelimb bones protect the animal from violent stresses during grappling.
P.Leo : 12%
M.Ursinus : 12%
Edge : Draw
HCMI :
It is Humeral circumference/articular length Often-used variable in analyses of bone strengths in locomotion. The higher the ratio is, the thicker the Humeral bone is.
P.Leo : 32%
M.Ursinus : 33%
Edge : M.Ursinus
HEI:
The HEI index measures the relative size of wrist stabilizing muscles and well as several grasping muscles in area which facilitate prey grasping such as m. extensor digitorum communis, m. extensor digitorum lateralis, m.flexor digitorum superficialis, m. palmaris longus,and m. flexor digitorum profundus. .These muscles also likely help stability, pushing, and agility when legs are on ground.
P.Leo : 26%
M.Ursinus : 31%
Edge : M.Ursinus
PC2 :
Scoring intermediate or low on PC2 are carnivorans that use their forelimbs to subdue,manipulate or excavate food items.Carnivorans scoring low on PC2, i.e. grapplers like felids, have relatively shallow trochlear furrows and relatively large and distally-projecting medial trochlear flanges. These features provide extra stability against forces acting in a nonparasagittal plane.
P.Leo : -0,531
M.Ursinus : -4,447
Edge : M.Ursinus
HTI :
It's Humeral trochlear length/Humeral length. Higher score increases muscle attachement on
the elbow joint and allows for more ulnohumeral flexion and extension.
P.Leo : 19%
M.Ursinus : 20%
Edge : M.Ursinus
Brachial index :
This measures radius length/humerus length. Lower scores in this ratio indicate greater forelimb muscle mechanical advantage and results in stronger muscles all else being equal.
P.Leo : 91%
M.Ursinus : 88%
Edge : M.Ursinus
Brachial index 2 :
This measures ulna length/humerus length. Lower scores in this ratio indicate greater forelimb muscle mechanical advantage and results in stronger muscles all else being equal.
P.Leo : 110%
M.Ursinus : 100%
Edge : M.Ursinus
Forelimb Proportion Index :
Length of proximal forelimb relative to length of distal forelimb ((Scapula length + Humerus length)/(Radius length + Metacarpal length)). Higher score Indicates greater degree of morphological specialization for producing large out-forces in the forelimb.
P.Leo : 141%
M.Ursinus : 159%
Edge : M.Ursinus
OI:
This metrics estimates tricep muscle strength. High values indicate greater ability to push with arms all else being equal. This helps a grappling cat hold prey and also helps a canid push and knock down an opponent. In addition, higher values may indicate greater stability and ability to change direction in a fight as well as greater relative mechanical advantage of the triceps brachii and dorsoepitrochlearis muscles used in elbow extension.
P.Leo : 20%
M.Ursinus : 22%
Edge : M.Ursinus
URI:
It is ulna mediolateral diameter at mid-shaft/humerus length. As mentioned above for humerus robusticity, Robust forelimb bones protect the animal from violent stresses during
grappling.
P.Leo : 5%
M.Ursinus : 7%
Edge : M.Ursinus
URI2:
This measures ulna anteroposterior diameter at midshaft divided by ulna length. As mentioned above for humerus robusticity, a robust ulna resists stresses on bones during fights and increases resistance to bites to the forelimb.
P.Leo : 8%
M.Ursinus : 12%
Edge : M.Ursinus
RRI :
This measures radius mediolateral diameter at midshaft divided by radius length. As mentioned above for humerus and ulna robusticity, a robust radius resists stresses on bones during fights and increases resistance to bites to the forelimb.
P.Leo : 9%
M.Ursinus : 9%
Edge : Draw
RRI2:
This measures radius anteroposterior diameter at midshaft divided by radius length. As mentioned above for humerus and ulna robusticity, a robust radius resists stresses on bones during fights and increases resistance to bites to the forelimb.
P.Leo : 6,1%
M.Ursinus : 6,6%
Edge : M.Ursinus
MANUS:
Manus digit 3 proximal phalanx length divided by metacarpal 3 length.Higher score Indicates greater relative proportions of proximal and distal elements of the manus and size of the palmar surface.
P.Leo : 39%
M.Ursinus : 60%
Edge : M.Ursinus
Foot Posture:
All else being equal, species that are able to adopt plantigrade foot posture, such as bears,badgers, wolverines, many rodents, spider monkeys, and great apes, should be able to apply greater free moments to the ground than species that are restricted to digitigrade or unguligrade foot posture. Relative to digitigrade foot posture, plantigrade posture improves performance in lateral striking, lateral pushing, downward striking,forward pushing and rearward pulling.
P.Leo : Digitigrade
M.Ursinus : Plantigrade
Edge : M.Ursinus
Studies used for the above comparison :
https://www.researchgate.net/publication/7531697_Body_size_ofSmilodon_Mammalia_Felidae
https://academic.oup.com/zoolinnean/article/142/1/91/2691231
https://www.researchgate.net/publication/298056854_Sexual_selection_on_skeletal_shape_in_Carnivora
As seen, the sloth bear has relatively stronger shoulders, thicker Forelimb bones, larger epicondyles, trochleas,olecrana, shorter forelimbs, bigger paws and the ability to produce more force based on its Forelimb Proportions and foot posture. Overall, the bear seems to have been a proportionally stronger,more robust and more muscular animal.