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Carnivore Evolution & Systematics MARE 390 Dr. Turner. }. Order Carnivora. 5 Families of Marine Mammals Mustelidae – Sea otter Ursidae – Polar bear Phocidae – Seals (true seal) Otariidae – Sea lions (eared seals) Odobenidae - Walrus. Pinnipeds. Order Carnivora.
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Carnivore Evolution & Systematics MARE 390 Dr. Turner
} Order Carnivora 5 Families of Marine Mammals Mustelidae – Sea otter Ursidae – Polar bear Phocidae – Seals (true seal) Otariidae – Sea lions (eared seals) Odobenidae - Walrus Pinnipeds
Order Carnivora Alternative hypotheses for relationships among carnivores
Order Carnivora Most debate centers around walrus
Order Carnivora Relationship among carnivores
Family Mustelidae Enhydra lutris Lutra lutra Molecular Morhpological
Suborder Pinnipedia “feather-footed” 34-36 species – (25% of marine mammals) 19 Phocids 14-16 Otariids 1 Odobenid }
Do the Evolution Adapted to an aquatic existence: 1. Large infraorbital foramen 2. Shortened & robust humerus/femur 3. Flattened ulna & radius, tibia & fibula 4. Elongate digits (I-hand) (I&V-foot) 5. Heterodont progressing toward homodont
Early Pinnipeds Pinnipedimorph - Fore & hind flippers modified for swimming Spent more time on land than extant pinnipeds
Early Pinnipeds Odobenids – evolved in the North Pacific during early Miocene – 18 mya Otariids – evolved in eastern North Pacific during middle Miocene – 11-12 mya Phocids – evolved in North Pacific during late Miocene – 18 mya
Continents in Early Miocene (20mya) 1- Early pinnipeds 4- Early pinnipeds
Continents in Middle Miocene (12mya) 1- Early phocids, 2 – Monachines & Odobenids, 3-4 - Phocines
Early Pinnipeds Monachine seals – evolved in the North Atlantic (Mediterranean); 1st dispersal to Caribbean, then Hawaii Phocine seals – evolved in North Atlantic; many in arctic Ribbon seals evolved in North Pacific, later separated by sister taxa (harp) in the North Atlantic
Meet the Pinnipeds Bear Otariid Odobenid Phocid Pinnipedimorph
Meet the Pinnipeds Otariid Odobenid Phocid
Meet the Pinnipeds Phocid Otariid Odobenid
Family Otariidae “eared seals” – external ear flaps (pinnae) Hawaiian monk seal (P) California sea lion (O)
Family Otariidae Turn hindflippers forward to walk on land
Family Otariidae Otariids smaller than most phocids Northern elephant seal (P) Steller’s seal lion (O)
Family Otariidae Shallower divers than phocids Harbor seal (P) California seal lion (O)
Family Otariidae Divided into 2 subfamilies: Otariinae (sea lions) & Arctocephalinae (fur seals) Otariinae (5 genera) Eumetopias, Neophoca, Otaria, Zalophus, Phocarctos Arctocephalinae (2 genera) Arctocephalus, Callorhinus
Extinct Genera Fur Seals Sea Lions Family Otariidae
Family Otariidae Subfamily Otariinae – Sea Lions - Pelage sparse Subfamily Arctocephalinae – Fur seals - Dense pelage
Subfamily Otariinae Eumetopias jubatus - Steller’s sea lion Neophoca cinerea - Australian sealion
Subfamily Otariinae Otaris byronis - Southern sea lion Otaria flavescens – South American sea lion Phocartos hookeri - New Zealand sea lion Zalophus californianus - California sea lion
Subfamily Arctocephalinae Arctocephalus australis - South American fur seal Arctocephalus forsteri - New Zealand fur seal Arctocephalus galapagoensis - Galapagos fur seal
Subfamily Arctocephalinae Arctocephalus gazella - Antarctic fur seal Arctocephalus philippi - Juan Fernandez fur seal Arctocephalus pusillus - Cape-Australian fur seal two subspecies: Cape fur seal - A. pusillus pusillus Australian fur seal - A. pusillus doriferus
Subfamily Arctocephalinae Arctocephalus townsendi - Guadelupe fur seal Arctocephalus tropicalis - Subantarctic fur seal Callorhinus ursinus - Northern fur seal
Family Odobenidae 1 species – Odobenus rosmarus - 2 subspecies* Odobenus r. rosmarus – N. Atlantic Odobenus r. divergens – N. Pacific (Odobenus r. laptevi – Laptev Sea)
Odobenid Classification Although tusks (elongate canines) are the most distinguishing trait – evolved from a single line Otariid Odobenid
Odobenid Classification Archaic walruses had enlarged canines and narrow premolars – indicative of piscivory rather than specialized mollusk diet today - more similar to Otariids & Phocids
Family Phocidae Divided into 2 subfamilies: Monachinae (monk, elephant, Antarctic) Phocinae (remaining N. Hemisphere seals) Monachinae (6 genera) Monachus, Mirounga, Lobodon, Ommatophoca, Hydrurga, Leptonychotes Phocinae (6 genera) Phoca, Histriophoca, Halichoerus, Erignathus, Pagophilus, Cystophora
Subfamily Monachinae Lobodon carcinophagus - crabeater seal Ommatophoca rossii - Ross seal Hydrurga leptonyx - leopard seal Leptonychotes weddellii - Weddell seal
Subfamily Monachinae Monachus monachus - Mediterranean monk seal Monachus schauinslandi - Hawaiian monk seal Monachus tropicalis - Caribbean (West Indian) monk seal
Subfamily Monachinae Mirounga leonina - southern elephant seal Mirounga angustirostris - northern elephant seal
Subfamily Phocinae Phoca vitulina - harbor (common) seal Phoca largha - largha (spotted) seal Phoca hispida - ringed seal Phoca sibirica - Baikal seal Phoca caspica - Caspian seal
Subfamily Phocinae Histriophoca fasciata - ribbon seal Halichoerus grypus - grey (gray) seal Erignathus barbatus - bearded seal Pagophilus groenlandicus - harp seal Cystophora cristata -hooded seal
Where’s Walrus The study of pinniped evolutionary relationships has identified a group of fossil pinnipeds – Desmatophocids
I am the Eggman Desmatophocids have recently been determined to be the common ancestors of phocids Contradicts previous works which recognized Desmatophocids as otariid pinnipeds
GOO GOO GOO JOOB “I haven't been this slim since High School” – Homer Simpson Most morphological data support a phocid & walrus alliance Molecular data consistently supports uniting otariids & walrus