Fish 475: Marine Mammalogy

Transcription

1 Fish 475: Marine Mammalogy Taxonomy III 5 April 2010 Course website:

2 Text reading reference: Section Pinnipeds: General characteristics I: 1. Rear limbs and pelvic girdle are present; 2. Modification of front and rear limbs as flippers; 3. In-water propulsion primarily by limbs, with some involvement of caudal spine in some cases; 4. Development of subcutaneous blubber layer.

3 Pinnipeds: General characteristics II: 5. Simplification of pelage; 6. Simplification of post-canine dentition; 7. Amphibious capability; 8. Breeding and post partum parental care done on solid substrata (land or ice).

4 Otariidae: Sea lions and fur seals: 16 species; In-water propulsion primarily with front flippers; Able to rotate rear limbs forward on land, allowing walking on all fours; External ear pinnae; Sexual dimorphism in size and skull structure present for many species. Pinniped families: Text reading reference: Section

5 Pinniped families: Otariidae: Sea lions and fur seals (continued): Breeding females alternate between periods of nursing and foraging trips at sea while caring for pups; Supraorbital processes pronounced on anterior skull; Absent from the North Atlantic.

6 Phocidae: Seals: Pinniped families: 19 species; In-water propulsion primarily with rear flippers and caudal spine; Unable to rotate rear limbs forward on land, thus unable to walk on all fours; No external ear pinnae; Sexual dimorphism in size for many species. Text reading reference: Section

7 Pinniped families: Phocidae: Seals (continued): Breeding females remain with pups during the entire period of lactation, fasting throughout; Supraorbital processes absent on anterior skull; Generally deeper and longer divers than other pinnipeds.

8 Pinniped families: Odobenidae: Walrus: One extant species; In-water propulsion involves front flippers, rear flippers and caudal spine; Able to rotate rear limbs forward on land, thus able to walk on all fours; No external ear pinnae; Sexual dimorphism is present but slight.

9 Pinniped families: Odobenidae: Walrus (continued): Extreme development of canine teeth; Shallow divers, foraging on bottomdwelling invertebrates; Breed and raise calves on sea ice; Make regular foraging dives while caring for dependent calves; Longest period of calf dependency among the pinnipeds up to three years.

10 Marine otters: Mustelidae: A family of carnivorous mammals that includes the marine otters: Two species generally recognized as marine mammals: Sea otter (Enhydra lutris) Marine otter (Lontra felina) First fully marine otter fossils are of Miocene age (approx 7 mya).

11 Sea otter: Marine otters: Specialized post-canines for crushing of hard-shelled marine invertebrates; Near shore habitats; Feeds on benthic marine invertebrates; Rear limbs modified as flippers; Extremely dense fur primary thermoregulatory barrier (no blubber).

12 Marine otters: Marine otter: Skull and dentition similar to other mustelids; Forages in nearshore ocean, breeds in rocky habitat just above high tide line, consuming fish and crustaceans; Limbs like other otters (excluding sea otter); Smallest of all the marine mammals; North American River Otter Skull

13 Polar bear (Ursus maritimus): Polar bear: In family Ursidae; Arctic and subarctic distribution; Forages on pinnipeds, primarily on sea ice; Minimal modifications for accommodation to marine living; Oldest fossil and subfossil remains are about 0.5 mya). Ansgar Walk

14 Sirenians: General characteristics I: 1 1. Loss of rear limbs and pelvic girdle; 2. Modification of front limbs as flippers; 3. Propulsion by caudal spine; 4. Development of caudal flukes or paddle lacking skeletal elements Text reading reference: Section 1.2

15 Sirenians: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Retention of terminal nostrils.

16 Sirenians: General characteristics III: 8. Simplification of teeth for mastication of plant matter; 9. Herbivorous diet and associated digestive anatomy and physiology; 10. Multilobed prehensile lips.