CETACEA Quintessential Mammals? Mammalogy – EEOB 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 Mysticete Feldhamer 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 Feldhamer

McVay, Am. Sci 61:24

Phylogeny & Classification of Odontoceti and Mysticeti Origin and evolution of cetaceans cladogram/ phylogeny Fig 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 , Feldhamer

Physeteridae Sperm whale Nat’l Geographic, 150:722a

The End Evolution & Systematics