Leptophoca is an extinct genus of from the North Atlantic realm.
Taxonomy
Leptophoca lenis was coined by Frederick True for a humerus from the Calvert Formation of Maryland.
[True FW. 1906. Description of a new genus and species of fossil seal from the Miocene of Maryland. Proceedings of the United States National Museum 30(1475):835-840] Later, Clayton Ray referred
"Prophoca" proxima from the Antwerp region, Belgium, to
Leptophoca.
[Ray CE. 1976a. Geography of phocid evolution. Systematic Biology 25(4):391-406.] A second nominal
Leptophoca species,
L. amphiatlantica, was coined for specimens found on both sides of the North Atlantic.
A 2017 study found
proxima and
lenis to be the same species, rendering
proxima the epithet of the
Leptophoca type species, but evidence for the validity of
L. amphiatlantica was deemed weak, rendering
amphiatlantica a
nomen dubium within
Leptophoca
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Description
Leptophoca is described as being similar in size to the modern-day harp seal. The humerus indicates primitive features, such as a reduced lesser tubercle, a straight diaphysis, and intermediate projection of the deltopectoral crest. A deep tendon groove in the forelimb also suggests increased manus flexion. All these features show an increased flexibility of the forelimbs, indicating that
Leptophoca would mainly utilize its forelimbs for aquatic and terrestrial locomotion and aid in propulsion, braking, and steering underwater. This contrasts with extant phocids, which mainly utilized their hindlimbs for propulsion while their forelimbs were limited in flexibility.
Skull features including a long rostrum and simplistic teeth indicated that
Leptophoca had a feeding mechanism that indicates rapid jaw closure, which benefits a grip and tear feeding strategy for grasping and shaking prey.
Leptophoca was a carnivore that fed on medium to large-sized endothermic prey which includes seabirds, large fish, and other marine organisms.
Based on ecomorphotype analysis,
Leptophoca
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