What are the characteristics of Sirenia?
Sirenians have the following morphological characteristics in common: robust body; tough, thick skin with little hair; two nostrils on top or at the front of a thick muzzle; no ear pinnae; no hind limbs; mammary nipples located near the axillae; forelimbs modified into flippers; horizontally flattened tail; and dense.
Do sirenians have hair?
The body of sirenians is sparsely covered in short hair (vibrissae), except for on the muzzle, which may allow for tactile interpretation of their environment.
What is the order of Sirenia?
Therapsid
Sea cows/Order
Do sirenians have teeth?
All sirenians are nearly hairless except at the muzzle, where there are thick sensory hairs called vibrissae. Manatees and dugongs differ in a number of traits besides the shape of the tail. Manatees lack incisor teeth, but incisors do occur in dugongs, erupting as tusks in the males.
Are Sirenia carnivores or herbivores?
Adult sirenians grow to lengths of between 2.8 and 3.5 meters and weights of between 400 and 1,500 kg. All sirenians are herbivores. Their diet varies from species to species but includes a variety of aquatic vegetation such as seagrass, algae, mangrove leaves, and palm fruit that falls into the water.
What is Palawan fossil Sirenia?
A fossil species of the Sirenia has been found on Palawan and possibly went extinct during the Miocene. Most of the described fossils are only known from their incomplete remains known from the Pleistocene. Antilope found in 1910, was suggested by Koenigswald in 1956, to be a bovid fossil rather than an antelope.
What are absent in Sirenia?
Hairs: Absent, except a few bristles around the muzzle which may also be absent in many whales.
Are walruses Sirenia?
Overview. Sirenians are one of four extant groups of marine mammals, the others being cetaceans (whales, dolphins, and porpoises), sea otters, and pinnipeds (walruses, earless seals, and eared seals). Sirenia also include Steller’s sea cow, extinct since the 18th century, and a number of taxa known only from fossils.
What is the scientific name of Palawan fossil Sirenia?
Palawan fossil Sirenia. Miocene. Dungongidae. Discovered in Palawan in 2011.
What word is the class Sirenia derived from?
Sirenia, commonly sirenians, are also referred to by the common name sirens, deriving from the sirens of Greek mythology. This comes from a legend about their discovery, involving lonely sailors mistaking them for mermaids. “Sea cow” is also the name for a hippopotamus in Afrikaans.
What distinguishes Sirenia Cetacea?
Most cetaceans also have some very sparse hair at some time in their development, but it is very much reduced compared to most other mammals. Also like modern whales, modern sirenians lack external hind limbs, have their forelimbs modified into flippers, and have flukes on their tails for locomotion.
Are cetaceans carnivores?
All cetaceans are carnivores and do not consume plants or algae as food. The large baleen whales eat schooling organisms that range in length from minute drifting mollusks, copepods (1 cm or less), krill (1–5 cm), and small fish and squid up to about 40 cm.
What kind of body does a Sirenia have?
Sirenians have a proportionally small head and compressed neck extending to a barrel chest with short forelimbs modified as flippers. The chest and abdomen taper to a peduncle in which either a large horizontally flattened paddle (manatee) or tail fluke (dugong) inserts.
What kind of animals live in the sirenian order?
The three species of manatee (genus Trichechus) occupy warm latitudes of the coastal Atlantic and associated rivers, and the dugong (Dugong dugon) inhabits the Sirenian, (order Sirenia), any of four large aquatic mammalian species now living primarily in tropical waters where food plants grow.
How many species of manatees are there in Sirenia?
Sirenia is a small order, composed of just two extant families, Dugongidae and Trichechidae, with four current species. Family Trichechidae includes three species: West Indian manatees ( Trichechus manatus ), African manatees ( Trichechus senegalensis ), and Amazonian manatees ( Trichechus inunguis ).
How did the order Sirenia get its name?
The order Sirenia was named after the Sirens of Greek mythology, and sirenians are believed to be the basis for the mermaid myth. Modern sirenians have two front limbs in the form of flippers but no hind limbs; even the pelvis is vestigial, and there are no skeletal remnants of leg or foot bones at all.