CETACEAQuintessential Mammals?

Mammalogy – EEOB 625

27 February 2004

Origins & Evolution: Another problem in macroevolution

• Were the first cetaceans herbivores or carnivores?

• Order Condylartha: ancestor to several ungulate taxa and cetaceans

• Pakicetus: an archaeocete of the Eocene, primitive? Heterodont, Skull not telescoped

• Neomorphic structures: tail fluke, dorsal fin

Horse

Archaeocete

Odontocete

MysticeteFeldhamer 16.4, see Vaughan Fig. 13-5

Adaptive Zones of Odontoceti and Mysticeti

• Body Size, Habitat, & Feeding specializations

• Advantages & disadvantages of large size?

• Seasonal & geographic variation in zooplankton as a food resource

• Food, migration, reproduction: Why might whales (mysticetes) be quintessential mammals?

1.__________, 2 ___________, 3___________• Relative success of the two suborders

Fig. 16.7Feldhamer

McVay, Am. Sci 61:24

Phylogeny & Classification of Odontoceti and Mysticeti

• Origin and evolution of cetaceans cladogram/ phylogeny Fig. 13-9• Is Cetacea a monophyletic taxon?• Are the two suborders valid taxa?

Probably, but are sperm whales and humpback whales closely related?

Relative “success” of the two suborders

Suborder Mysticeti • Baleen: What is it?

Feeding behavior & adaptations of the 3 families:

• Balaenidae – swim & skim

• Balaenopteridae – gulp & strain

• Eschrichtiidae – strain sediments

Fig. 16.9, Feldhamer

Minke Gray

Blue

Size & shape of baleen plates

Bowhead

Fig 4. McVey

Balaenidae

Balaenopteridae

grand gulpers

Eschrichtiide

Feeds on benthic invertebrates

National Geographic

Suborder Odontoceti • Most diverse and abundant• Delphinidae ‑ 32 species, marine & freshwater (river) species• Physeteridae ‑ sperm whales and whale strandings• What about Plantanistidae?

Fig. 16.11, Feldhamer

Physeteridae

Sperm whale Nat’l Geographic, 150:722a

The End

Evolution & Systematics