Topic 14
Pholidota is part of superorder
Laurasiatheria
The Order Pholidota has one family
Manidae, three genera, (Manus, Phataginus, and Smutsia) and eight species.
Suborder Folivora is made up to two families
Megalonychidae and Bradypodidae, each family has one genus (Choloepus and Bradypus respectively), and 6 species, 2 in Choloepus and 4 in Bradypus.
Suborder Vermilingua details
b] Anteaters are mostly solitary mammals and are territorial. 1] They do not normally enter a territory of another anteater of the same sex, but males often enter the territory of associated females. c] Their eyesight is poor but their sense of smell is excellent. d] They are found in portions of South and Central America.
The first tooth is a modified premolar that looks a bit like a canine tooth. 1} This tooth is termed
caniniform
Xenarthrose
extra articulating processes. 1] The xenarthroses arise from the lumbar and posterior thoracic vertebrae. 2] The xenarthosis arises from the vertebra near the cranial articulating process/prezygapophysis. a} It, along with the cranial articulating process, articulates with the caudal articulating process/postzygapophysis of the vertebra cranial to it. 1} This forms a rigid frame. (a) One advantage to this is to support the dermal armor of the Cingulata.
Superorder Xenarthra
Superorder Xenarthra is made up of the orders Pilosa and Cingulata. 1) Today they are found primarily in Central and South America with one species, the nine-banded armadillo (Dasypus novemcinctus), being found in warmer regions of North America. a] The superorder originated in South America approximately 59 m.y.a. 1] They diversified extensively during the time that South America was isolated. a} During the Great American Interchange a number of species migrated into North America including ground sloths (family Megatheridae) and glyptodonts (subfamily Gylptodontinae).
Order Cingulata
The Armadillos a) Order Cingulata has one family, Dasypodidae, nine genera, and 21 species. 1) Some feel that there should be two families, Dasypodidae and Chlamyphoridae.
Family Cyclopedidae
The Silky or Pygmy Anteater a] This family has one species, Cyclopes didactylus. 1] This anteater is arboreal and has a partially prehensile tail. 2] It is the smallest species of anteater. (a) Recent molecular studies have determined that this is really not one but multiple (~6) species.
Family Megalonychidae
The Two-Toed Sloths a] Family Megalonychidae is composed of two extant species and a number of extinct species including the various ground sloths. 1] The two extant species are found in South and Central America.
Order Pilosa is made up of two suborders
folivora (the sloths) and Vermilingua (the anteaters)
Cingulata originated in South America and almost all species are restricted to Central and South America. a] The one exception is the
nine banded armadillo, Dasypus novemcinctus, which is found in the southern portion of North America.
The name Xenarthra means
strange joints
Armadillos are the only mammals to have a
synsacrum
Myrmecophaga tridactyla
the giant anteater, is purely terrestrial and found in open grasslands.
Tamandua mexicana
the northern Tamandua is semiarboreal and will forage in the tress and on the ground. a} To aid with digestion they will also ingest small rocks. b} Its range extends into southern Mexico.
Chlamyphoridae
the proposed FAMILY of Order Cingulata that consists of the pink fairy armadillo (Chlamyphorus truncatus)
Tamandua tetradactyla
the southern Tamandua is semiarboreal and will forage in the tress and on the ground. a} To aid with digestion they will also ingest small rocks. b} Both species of tamandua are medium sized anteaters
Family Bradypodidae
three-toed sloths one genus and four species. 1] The four species are found in South and Central America
Instead the center of the tooth is filled with a specialized dentin arranged into parallel rods called
vasodentin (aardvark)
xenarthry
vertebrae have extra articulations that are unique among mammals.
The orders Pilosa and Cingulata are related to one another and make up the superorder
xenarthra
Convergent Anatomical Features
1) long snouts, 2) long tongues, 3) submandibular salivary glands that produce a mucus rich secretion, 4) reduced or absent dentition, a] This is where the term "edentata" came from. 5) a reduced coronoid process (of the dentary), 6) and enlarged hyoid elements to anchor the tongue muscles. 7) They also have small pinnae and valvular nostrils to deal with biting insects.
Both families have incomplete zygomatic arches
1] The squamosal is missing. 2] Also, the jugal bone has upper and lower processes on the posterior edge.
armadillo adaptations
1] They have a reduced dentition. a} They lack incisors and canines. b} Their cheek teeth are simple and peg-like. 1} Their teeth lack enamel. 2] They have an elongated, sticky tongue. 3] Their forelimbs are powerful and heavily clawed. 6) Armadillos are primarily nocturnal but can be daytime active. 7) They have poor vision but good olfaction.
Features of the Three-Toed Sloths
1] They have three digits on the forefoot (manus) with long claws. 2] They have 8 or 9 cervical vertebrae. 3] These species lack incisors and canines. 4] Their premolars and molars are very reduced, being peg-like, and indistinguishable. Collectively they are called simply molariform. a} They lack the caniniform premolar of Megalonychids. c] The fossil record for these sloths is sparse and their relationship with other sloths is questionable.
Features of the Two toed Sloths (C. didactylus and C. hoffmanni)
1] They have two toes on the forefoot (manus) and each claw is long. a} Their hindfoot has three digits that also bear long claws. 2] They are larger, more active, and faster moving than are three toed sloths (Bradypus). 3] The dentition of Choloepus is reduced. a} They lack incisors and canines. b} The cheek teeth are reduced and number 5. c} The first tooth is a modified premolar that looks a bit like a canine tooth. 1} This tooth is termed Caniniform. 2} It is separated from the other cheek teeth by a diastema. d} Their teeth continue to grow throughout their life time. 4] Unlike most mammals that have 7 cervical vertebrae they can have between 5 to 8.
cranial articulating process, articulates with the caudal articulating process/postzygapophysis of the vertebra cranial to it.
1} This forms a rigid frame. 2) The ischia (of the pelvis) and the sacrum are fused. 3) In most members of the superorder the clavicle and acromion are robust and well developed. 4) The members do not have front incisor teeth and canines. They also lack, or have poorly developed, molars. 5) The members of superorder Xenarthra have the lowest metabolism and internal temperature of any eutherians (30-34 °C). 6) The males have internal testes. 7) They also have a tendency to develop dermal ossicles.
Tubulidentata is part of superorder
Afrotheria
Suborder Vermilingua
Anteaters
Order: Cingulata
Family: Dasypodidae (armadillos) (9, 21)
Order: Pholidota (1, 8)
Family: Manidae (pangolins) (1, 8)
Order: Pilosa
Family: Megalonychidae (2-toed sloths) (1, 2) Family: Bradypodidae (3-toed sloths) (1, 4) Family: Myrmecophagidae (true anteaters) (2, 3) Family: Cyclopedidae (silky anteater) (1, 1)
Order: Tubulidentata (1, 1)
Family: Orycteropodidae (aardvark) (1, 1)
Megalonychids first reached North America by island-hopping, about 9 m.y.a., prior to the formation of the
Isthmus of Panama (i.e.; prior to the Great American Interchange).
Armadillos are known for their armor
It is composed of plates of dermal bones called Osteoderms covered by keratinized epidermal scales called Scutes
Xenarthrous process
Intervertebral articulations on lumbar & posterior thoracic vertebrae
Suborder Vermilingua is composed of two families,
Myrmecophagidae and Cyclopedidae, 3 genera (2 and 1 respectively), and four species (3 and 1 respectively).
Order Tubulidentata is composed of one family
Orycteropodidae, one genus and one species, Orycteropus afer, the aardvark.
pangolin nickname
Sometimes called the "scaly anteaters" the word pangolin comes from the Malay word pengguling meaning "something that rolls up".
Sloth fur has specialized functions.
The outer hairs grow in a direction opposite from that of other mammals. a} In most mammals, hairs grow toward the extremities, but because sloths spend so much time with their legs above their bodies, their hairs grow away from the extremities providing protection from the elements while the sloth hangs upside down. 2] When moist, the fur hosts two species of symbiotic cyanobacteria. They may confer two advantages: a} The cyanobacteria may provide camouflage. T 1} The outer fur coat is usually a thick brown, but occasionally wild sloths appear to have a green tinge to their fur due to the presence of these bacteria.
Family Myrmecophagidae
a] These are the medium to large anteaters and are found in Central and South America, from southern Belize and Guatemala to northern Argentina. b] They have no teeth and instead have modified spine-like papillae on the tongue to help trap insects. c] The three species are:
pangolin characteristics
a] When under threat they will roll into a ball, with the tail wrapped over the head, and the scales raised to their sharp, pointed ends are facing outwards. 1] They will also produce a noxious scent from their anal glands. b] These scales are not true scales but are agglutinized hair, more like the hair horns of rhinoceros. 1] They can make up almost 25% of the animal's overall mass. b) These animals are native to tropical regions of Africa and Asia. c) Pangolins range in length from 30 to 100 cm in length. 1) Males are usually larger than are females. d) Most are primarily nocturnal. 1) However, one species, the long tailed pangolin (P. tetradactyla), can be daytime active.
Order Tubulidentata
aardvark
At one time all four orders were placed in the Order
edentata
Synsacrum
is the fusion of the sacrum, first caudal vertebrae, lumbar and last thoracic vertebrae, and innominate bones.
zygapophysis
one of the two paired processes of a vertebra that interlock it with the adjacent vertebrae.
