Mammalian Taxonomy, Morphology, and Natural History

Vocabulary practice flashcards covering mammalian taxonomy, morphology, anatomical specializations, and species-level characteristics of Eutheria.

Juramaia sinensis

The earliest known fossil eutherian, dating to approximately $160\,MYA$ in China, translating as 'Jurassic mother from China.'

Eomaia scansoria

An early scansorial eutherian fossil found in China that dates to approximately $125\,MYA$.

Atlantogenata

A placental mammal magnorder of South American and African origin comprising the superorders Afrotheria and Xenarthra.

Boreoeutheria

A placental mammal magnorder encompassing the northern-origin superorders Laurasiatheria and Euarchontoglires (Supraprimates).

Stridulating quills

Specialized protective spines in some tenrecs (family Tenrecidae) that are rubbed together in conjunction with tongue clicks for acoustic communication.

Potamogalidae

The otter shrew family of semiaquatic African afrosoricids characterized by a lack of auditory bullae and high-spined caudal vertebrae for side-to-side tail undulation.

Chrysochloridae

The golden mole family of fossorial afrosoricids featuring dense iridescent pelage, vestigial eyes, an enlarged malleus for seismic hearing, and three forearm bones.

Macroscelididae

The elephant shrew family (order Macroscelidea) characterized by a long flexible snout, palatal fenestrae, dilambdodont molars, and clearing distinct trails in vegetation.

Tubulidentata

An afrotherian order containing the aardvark (family Orycteropodidae), which exhibits enameless columnar teeth, extensive nasal turbinates, and specialized myrmecophagy.

Paenungulata

A clade of 'almost hooved' afrotherians (Hyracoidea, Proboscidea, and Sirenia) united by abdominal testes, lack of a clavicle, and microbial hindgut fermentation in an enlarged cecum.

Procaviidae

The hyrax family of Paenungulata, possessing suction-generating foot gland secretions, elastic traction pads, and poor thermoregulation mitigated by group basking.

Musth

A heightened reproductive period in adult male elephants marked by copious frontalin secretion from the temporal glands, signaling high testosterone levels.

Mesial drift

The conveyor-belt-like forward displacement and sequential eruption of elephant cheek teeth through the jaw over the animal's lifetime.

Sirenia

An order of completely aquatic, herbivorous placental mammals (dugongs and manatees) characterized by pachyostotic bones for buoyancy control and horizontal tail flukes.

Xenarthrales

Extra intervertebral accessory articulations on the lower thoracic and lumbar vertebrae ($T8\text{ to }L5$) that provide spinal rigidity and bracing against digging forces in xenarthrans.

Dasypus mexicanus

The Mexican long-nosed armadillo, known for embryonic diapause that splits into four identical quadruplets, as well as serving as a carrier of leprosy.

Mycobacterium leprae

The intracellular, slow-growing bacterium causing leprosy (Hansen's disease) that infects human and armadillo peripheral nerves, skin, and nasal mucosa.

Bradypodidae

The three-toed sloth family, characterized by folivorous diets, foregut fermentation, symbiotic green algae in pelage, absence of canines, and $6\text{ to }9$ cervical vertebrae.

Solenodontidae

A primitive eulipotyphlan family of venomous Caribbean insectivores with zalambdodont molars and grooved second lower incisors that deliver neurotoxic saliva.

Erinaceidae

A eulipotyphlan family consisting of spined hedgehogs and unspined gymnures (moonrats) possessing quadrate, bunodont molars and regular torpor or hibernation strategies.

Soricidae

The true shrew family, distinguished by double-condyloid jaw articulations, lack of zygomatic arches and auditory bullae, dilambdodont molars, and high metabolic rates.

Talpidae

The mole family of Eulipotyphla, exhibiting fusiform bodies, keeled sterna for extensive pectoral muscle attachment, and outward-rotated paddle-like forefeet.

Eimer's organ

Specialized sensory, tactile (and potentially electroreceptive) epidermal organs found on the snouts and snout tentacles of talpid moles.

Scandentia

An order of Southeast Asian omnivores (tree shrews) possessing the highest mammalian brain-to-body mass ratio, pectinate lower incisors, and a perforated zygomatic arch.

Dermoptera

An order of nocturnal folivorous gliders (colugos) possessing pectinate lower grooming incisors and a broad patagium that extends to the tips of digits and tail.

Patagium

The extensive, furred gliding membrane spanning between the neck, forelimbs, hindlimbs, digits, and tail in dermopterans.

Strepsirrhini

The primate suborder of lemurs and lorisoids, characterized by moist rhinaria, lower incisor toothcombs, lack of a post-orbital plate, and endogenous vitamin C production.

Haplorrhini

The primate suborder of tarsiers, monkeys, and apes, characterized by dry rhinaria, complete post-orbital plates, foveae centrales, and lack of endogenous vitamin C production.

GULO gene

The gene encoding L-gulonolactone oxidase, mutated and non-functional in haplorrhine primates, necessitating dietary intake of ascorbic acid (vitamin C).

Platyrrhini

The parvorder of New World monkeys characterized by broad nasal septa, three premolars per quadrant ($12$ total premolars), and occasionally prehensile tails.

Catarrhini

The parvorder of Old World monkeys, apes, and humans characterized by narrow nasal septa, trichromatic vision, non-prehensile tails or no tails, and two premolars per quadrant ($8$ total premolars).

Duplicodonty

The lagomorph dental configuration featuring two pairs of upper incisors ($2/1$ incisor formula), with a tiny, peg-like pair situated behind the primary incisors.

Cecotropes

Soft, nutrient-dense green fecal pellets produced in the cecum that lagomorphs re-ingest (coprophagy) for nutrient extraction prior to voiding dry pellets.

Ochotonidae

The pika family of cold-adapted lagomorphs, characterized by round ears, concealed tails, maxillae with fenestrae, lack of supraorbital processes, and haypile food caches.

Leporidae

The rabbit and hare family, defined by elongated hindlimbs, fenestrated maxillae and parietals, supraorbital processes, and an intracranial flexion joint.

Protrogomorphous

The primitive rodent jaw condition, retained only in mountain beavers (family Aplodontidae), where the infraorbital foramen is small and masseter attachment is restricted to the zygomatic arch and lower jaw.

Sciuromorphous

The rodent jaw condition where the anterior zygomatic arch forms a broad zygomatic plate from which the lateral masseter originates, leaving a small infraorbital foramen.

Hystricomorphous

The rodent jaw condition where the infraorbital foramen is greatly enlarged, permitting the medial masseter to pass through to the maxilla for strong chewing.

Myomorphous

The rodent jaw condition combining a zygomatic plate with an enlarged infraorbital foramen through which the medial masseter passes, balancing gnawing and grinding forces.

Castoridae

The semiaquatic castorimorph family of beavers, characterized by sciuromorphous skull architecture, cloacal folds, castor glands yielding castoreum, and dam-building engineering.

Geomyidae

The pocket gopher family of fossorial rodents, characterized by external fur-lined cheek pouches and lips that seal behind projecting incisors to keep dirt out.

Heteromyidae

The castorimorph family of kangaroo rats and mice, characterized by external fur-lined cheek pouches, ricochetal bipedal locomotion, and greatly enlarged auditory bullae.

Muridae

The largest mammalian family (Old World rats and mice), defined by myomorphous jaw structures and molars with three longitudinal rows of cusps from labial to lingual margins.

Cricetidae

The second largest mammalian family (New World rats, mice, and voles), distinguished by myomorphous jaws and molars bearing two cusp rows or complex prismatic enamel patterns.

Zapodidae

The jumping mouse family, distinguished by elongated hindlimbs and tails exceeding head-body length, grooved upper incisors, and hibernation periods lasting up to $8\text{ months}$.