Class Mammalia Order Sirenia Florida Manatee Trichechus manatus

Class Mammalia, Order Sirenia Florida Manatee - Trichechus manatus latirostris

Bottom resting Feeding Swimming Courtship A B C Hartman, 1979

Manatees • Strategies to stay on bottom at low cost • Dense and heavy bones • Dense skin • Large lungs Ballast

Maneuverability • Pectoral flippers or tailfluke • Contractions of hemidiaphragms • Position in water column • Pitch and roll

Compartmentalization • Need to be distinct muscular units • Separated by connective tissue elements • With separate sources of innervation • Termed “neuromuscular compartments”

Hypothesis Manatee hemidiaphragms are compartmentalized.

Rommel and Reynolds, 2000

Rommel and Reynolds, 2000

Methods • Gross anatomical studies

Manatee diaphragm Rommel and Reynolds, 2000

Connective tissue elements VC Bundles Phrenic nerve

Connective tissue elements VC Bundle

Connective tissue elements VC Bundles X X X

Multi-directional fibers Intrinsic Tongue Muscles Manatee Diaphragm M. Newson, 1996

Innervation patterns Phrenic nerve VC bundle Branches of phrenic nerve

Conclusions • VC bundles separate diaphragm into 1. 0 cm-wide blocks • Muscle fibers insert into VC bundles • Branches of phrenic nerve innervate groups of blocks • Compartments may be composed of groups of blocks

D. Perrine, 2001

CARIBBEAN

Class Mammalia, Order Sirenia Caribbean (Antillean) manatee - Trichechus manatus

Class Mammalia, Order Cetartiodactyla, Suborder Odontoceti – toothed whales Bottlenose dolphin (Tursiops truncatus)

By www. iucnredlist. org, CC BY-SA 3. 0, https: //commons. wikimedia. org/w/index. php? curid=18

Adults 6. 6 to 13. 1 feet 330 to 1, 430 lbs. Males > Females By Kurzon, CC BY-SA 3. 0, https: //commons. wikimedia. org/w/index. php? curid=21

Class Mammalia, Order Cetartiodactyla, Suborder Mysticeti – baleen whales Humpback whale (Megaptera novaeangliae)