Fish 475: Marine Mammalogy

Transcription

1 Fish 475: Marine Mammalogy Wednesday, 31 March 2010 Course website: Pieter Folkens

2 Taxonomy

3 Cetaceans: General characteristics I: 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 lacking skeletal elements Text reading reference: Section

4 Cetaceans: General characteristics I: 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 lacking skeletal elements.

5 Cetaceans: General characteristics I: 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 lacking skeletal elements.

6 Cetaceans: General characteristics I: 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 lacking skeletal elements.

7 Cetaceans: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Development of dorsal nostrils.

8 Cetaceans: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Development of dorsal nostrils.

9 Cetaceans: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Development of dorsal nostrils.

10 Cetaceans: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Development of dorsal nostrils.

11 Cetaceans: General characteristics II: 5. Loss of pelage; 6. Development of subcutaneous blubber layer; 7. Development of dorsal nostrils.

12 Odontoceti: The toothed whales About species; Diverse and (mostly) abundant in all the world s oceans and seas; Concentrated in or near regions of high productivity; Typically do not make major migrations. Text reading reference: Section

13 General characteristics of the Odontocetes I: 1 1. Skulls Asymmetrical (we ll see this more clearly in lab); 2. Dorsal skull surface flat or concave; 3. Mandibles articulated distally ( mandibular symphysis important diagnostic feature in evolution and taxonomy); 2 4. Homodont dentition, with numbers of teeth highly variable zero to many ( supernumerary ). 5. Modification of posterior mandible as an acoustic receptor 3 4 5

14 General characteristics of the Odontocetes II: 5. Nostrils single externally; 5

15 General characteristics of the Odontocetes II: 5. Nostrils single externally; 5 6. Extreme development of acoustic transmission and sensory capabilities. 6

16 Odontocete families: Ziphiidae: Beaked whales Cuvier s beaked whale Teeth few or absent, in some species present only in males; Skull concave with sagittal crests Hubbs beaked whale Grooved throat with expansion capability (unique among the odontocetes).

17 Odontocete families: Monodontidae: Beluga and narwhal Two species, occuring at present only in the high Arctic; Most highly ice-adapted of all the odontocetes.

18 Monodontidae: Beluga and narwhal Skulls flattened; Belugas have moderate numbers of teeth; Narwhals males have a tusk but no other teeth; females have no teeth. Odontocete families:

19 Odontocete families: Physeteridae: Sperm whale

20 Odontocete families: Physeteridae: Sperm whale One species, the largest of the odontocetes and one of the largest of all the whales; Extreme development of diving and acoustic capabilities. Strongly sexually dimorphic in size and ecology (males undergo extensive annual migrations as adults, females do not).

21 Odontocete families: Physeteridae: Sperm whale Teeth only in lower jaw; Extreme asymmetry of skull; Left nostril does not open to the exterior, functioning only in acoustic context; All respiration through the right nostril; Deflected blow at sea.