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alveolus - A small cavity or pit, as a socket for a tooth. Alveolar length of a tooth-row therefore denotes the length of the row of the teeth, taken from the posteriormost place where the back tooth emerges from the bone to the anteriormost point where the front tooth in the row emerges from the bone—the overall length of the bony sockets for the row of teeth. Plural is alveoli.

anagenesis - The evolutionary change of an ancestor-descendant line without the line splitting into two separate species. Thus a single population changes evolutionarily through time. Eventually, a later population may be so different from its ancestral population that our nomenclatural system requires it be given a different species name.

baculum - Also known as the os penis, this is a bone found in the penis of many mammals, including bats, rodents, carnivores, and many primates. In many mammals, it is of taxonomic and discriminatory value.

Biogeography. The science that studies the distributional history of organisms and the factors governing the distribution of organisms.

BP - "before present". Commonly used for radiocarbon dates, and "before present" is defined as 1950 (so as to allow dates made at different times to be comparable). Radiocarbon dates differ from calendar dates and required calibration to bring them into conformity with calendar dates.

brachyodont - Describes cheekteeth that are low crowned. That is, the enamel portion of the tooth (the crown) is relatively short and doesn't penetrate into the jaw bones even in young animals. The opposite is hypsodont; hypsodont teeth are high crowned.

cal kya - Calibrated dates to bring them into conformity with calendar years. "kya" stands for thousands of years ago. An example of calibrated dates is seen in the abrupt change from warming temperatures to ice-age temperatures at the start of the Younger Dryas; this is dated by radiocarbon as approximately 10,900 BP; the calibrated date is about 12,900 cal years (=12.9 kya).

carnassials - Teeth specialized for slicing meat. The Carnivora is typified by possession of a carnassial pair consisting of upper premolar 4 and lower molar 1.

canine - Of, pertaining to, or designating the tooth next to the incisors in mammals. Of or pertaining to dogs or to the family Canidae.

carnivore - An animal that preys on other animals; an animal that eats the flesh of other animals; especially any mammal of the order Carnivora, but not limited to that order.

cheek teeth - Teeth posterior to the canines.

clade - A taxon and all of its descendants. For example, the Canis clade includes the ancestor of all members of the genus Canis and all the species descended from that ancestor.

condylar (articular) process - On a mandible, the process ending in the articular condyle.

congeneric - Belonging to the same genus.

coronoid process - The upward projecting process of the posterior part of the mandible, giving attachment on its outward side to the masseter muscle and on its inner side to the temporal muscle.

cursorial - Adapted for running.

Deep sea cores. Long sections of sediment collected from ocean bottoms. A variety of techniques allow climatic interpretations over geologic time based on information obtainable from the sediments.

dental formula (plural, formulae) - A brief method for expressing the number and kind of teeth of mammals. The abbreviations i (incisor), c (canine), p or pm (premolar), and m (molar) indicate the kinds in the permanent dentition, and the number in each jaw is written like a fraction, the figures above the horizontal line showing the number in the upper jaw, and those below, the number in the lower jaw. For deciduous teeth, the abbreviation is preceded by "d".

dentine - A calcareous material, harder and denser than bone, which composes the principal mass of a tooth.

dentition - The teeth, considered collectively, of an animal.

diastema - A vacant place or gap between teeth in a jaw.

diurnal - Active during the day.

enamel - Of teeth, the hardest substance of the mammalian body and forming a thin layer that caps or partly covers a tooth.

endemic. Occurring only in that place. Thus a plant occurring only in the Franklin Mountains is endemic to that mountain range.

epiphysis. Plural, epiphyses. Separate ossifications in embryos and young mammals at the ends of long bones and vertebrae that are separated from the main shaft of the bone by epiphyseal cartilage. Epiphyses eventually fuse to the shaft (diaphysis).

Fauna. The animals of an area. Best used as a collective term (e.g., "The North American Pleistocene fauna"), although some authors use it as a synonym for animal.

femur (plural, femora) - The proximal bone of the hind limb.

flora - All the plants of some geographic area or geologic time. Thus, "the Pleistocene flora of North America" refers to all the plants present in North America during the Pleistocene Epoch. Sometimes used as a synonym for plants, but better practice restricts it to a collective term (e.g., not "We saw some flora," but "We tabulated the flora of the area").

foramen magnum - The large opening in the back of a skull through which the spinal cord passes to become the medulla oblongata of the brain.

forearm - The part of the forelimb between the elbow and wrist.

fossils. Any recognizable trace of past life. Among others, traces may include unaltered remains, parts of organisms that have been replaced by minerals, casts or molds where no part of the original specimen has been preserved but where the shape and ornamentation has been replicated, and tracks.

frontal - Pertaining to or designating the bone (paired) immediately in front of the parietal bone and behind the nasal. Bones that form the forehead, the bones above the eyes.

genus - A formal obligate rank of the taxonomic hierarchy lying between species and family. A genus consists of one or more species that are believed to be more closely related to one another than any is to any species of a different genus. The plural is genera.

osteoderm - Various vertebrates have bony nodules or plates buried within the skin. These are osteoderms (osteo for bone, derm for skin).

Half Life. The time it takes for half of a sample of radioactive material to change to a daughter isotope or element. Thus if you started with a pound of such a substance, you would have one-half pound left after 1 half life; one-fourth pound after 2 half lives, one-eighth pound after 3 half lives, and so forth, halving the remaining sample each half life.

habitat - The kind of environment in which a species of organism is normally found.

horizontal ramus - In a lower jaw, the segment of bone ("ramus" = branch) bearing the teeth, and anterior to the vertical ramus (the segment raising upwards at the back of the jaw).

hypselodont - Teeth that are rootless and thus grow throughout life.

hypsodont - Teeth that have a high crown (the enameled portion of the tooth) and short roots. Often called high crowned teeth.

incisive foramina - The anterior palatine foramina (singular, foramen), of which there are two, in the bony roof of the anterior part of the cavity of the mouth at the juncture of the premaxillary bones and maxillary bones; transmit nasal branches of palatine arteries and nasopalatine ducts of Jacobson.

incisor - Pertaining to or designating one of the teeth in front of the canine tooth; those in the upper jaw invariably are in the premaxillary bone.

infraorbital canal - A canal through the maxillary bone from the orbit to the face.

insectivorous - Eating insects; preying or feeding on insects.

in situ - In place, not coming from elsewhere.

interorbital constriction - The least distance across the top of the skull between the orbits (eye sockets).

interorbital region - The region between the eye sockets; the region of the skull between the rostrum and the braincase.

interparietal - Pertaining to or designating the bone (rarely paired) immediately in front of the supraoccipital bone and between the two parietal bones.

interstadial - A relatively warm period within the Pleistocene. For example, the early part of the Wisconsin glacial age was separated from the later portion by an interstadial that was warmer and with less continental ice than before or after.

Isotope. Different forms of a chemical element that differ in atomic weight, but not in chemical activity. The atomic weight usually is given as a superscript before the abbreviation of the chemical. Thus 12C, 13C, and 14C are three isotopes of carbon.

ky - Thousands of years.

kya - Thousands of years ago.

mastoid - Designating or pertaining to the mastoid bone (paired) or its process. This bone is bounded by the squamosal bone, the exoccipital bone, and the tympanic bone.

maxillary breadth - Width of skull from some designated place on the lateral face of the right maxillary bone (maxilla) to the corresponding place on the left maxillary bone; in shrews, across the ends of the zygomatic processes of the two maxillary bones.

maxillary toothrow - The row of teeth in one maxillary bone; in most mammals all the premolars and molars on one side of the upper jaw.

mesic - Said of a habitat or geographic region that has ample water.

metacarpal - Of or pertaining to a metacarpal bone. A bone of the hand or forefoot between the wrist and fingers; when all the digits are present, there are five more or less elongated metacarpal bones, one at the base of each digit.

M2 - Designation of the second true molar in the upper jaw of a mammal.

MIS (Marine Isotope Stage) - Changes in proportions of the isotopes of oxygen in the calcium carbonate shells of organisms recovered from deep sea cores reflect the amount of ice tied up on the continents. Times of high levels of the 18O isotope indicate significant glacial activity. Warm marine isotope stages have been given odd numbers and cold intervals even numbers. Thus the present, warm Holocene is MIS 1; the late Wisconsin full-glacial time is Marine Isotope Stage 2; the mid-Wisconsin warmer part is stage 3; the early Wisconsin glacial is stage 4; and the Sangamon interglacial is MIS 5. The isotope record extends far into the past, with the Pleistocene now defined as beginning at MIS 103.

molar - Of or pertaining to a molar tooth. One of the teeth behind the premolar teeth; a molar tooth is not preceded in embryological development by a deciduous (milk) tooth.

molarization - The phenomenon of one or more of the premolars becoming molariform (that is, becoming morphologically and functionally similar to molars).

my. The abbreviation for millions of years.

mya. The abbreviation for millions of years ago.

nasal - Of or pertaining to the nose, as a nasal bone (paired) on the dorsal surface of the skull at its anterior end. A nasal bone.

NISP - Number of identifiable specimens. Assuming a roughly comparable number of identifiable skeletal/dental elements among taxa, the NISP gives a rough idea of the relative numbers of individuals per taxon. For example, an NISP of 5 for Desert Cottontail and 25 for Mountain Cottontail results in a rough estimate of about five times as many Mountain Cottontails as Desert Cottontails. Sample error, of course, can be large.

North American Land Mammal Age (NALMA) - Time ranges within which particular associations of mammals occur. The Pleistocene includes the later portion of the Blancan Land Mammal Age. This is followed by the Irvingtonian and the Rancholabrean.

occlusal - Of or pertaining to the grinding or biting (occluding) surface of a tooth. The part of the tooth that meets the teeth of the complementary jaw.

orbit - The cavity in the skull in which the eye and its appendages are situated; the eye socket.

P3 - Designation of the third (next to last) premolar in the upper jaw of a mammal. Capital letters designate teeth in the upper jaw and lowercase letters designate teeth in the lower jaw.

palatal - Of or pertaining to the palate (as generally used, the bony roof of the mouth made up of two palatine bones, two maxillary bones, and two premaxillary bones).

secondary palate - The roof of the mouth, consisting of the structures that separate the mouth from the nasal cavity. The bony palate is composed of the premaxillae, maxillae, and palatines.

paleontology. The study of fossils (recognizable traces of past life).

parietal - Pertaining to or designating the parietal bone (paired) roofing the braincase. This bone is behind the frontal bone and in front of the occipital bones.

postorbital - Situated behind the eye, as postorbital process of the frontal bone or postorbital process of the jugal bone.

premaxillary - Of or referring to the premaxilla, a bone (paired), in the mammalian skull bearing the incisor teeth of the upper jaw; the premaxilla is situated in front of the maxilla.

premolar - Designating or pertaining to one of the teeth (a maximum of 4 on each side of upper jaw and lower jaw of placental mammals, or 16 in all) in front of the true molars. When canine teeth are present, premolars are behind these teeth; premolars are preceded by deciduous teeth, and in the upper jaw are confined to the maxillary bone.

prismatic - Describes teeth that appear to be made up of a number of more or less triangular, joined prisms set on end. See Arvicolinae.

radioactive decay. Some kinds of isotopes emit radiation during nuclear events, changing into a different isotope of the same element or into a different chemical element. The change of one isotope or element into another is known as radioactive decay and proceeds at a characteristic rate for each isotope (the half-life).

reentrant angle - An infold of the enamel layer on the side, front, or back of a cheek-tooth, as in a molar of a muskrat or wood rat.

rostrum - Of a mammalian skull, the part projecting in front of the orbits.

sagittal crest - The ridge of bone at the juncture of the two parietal bones resulting from the coalescence of the temporal ridges; in old individuals of many species of mammals, the crest extends from the middle of the lambdoidal crest anteriorly onto the frontal bones and divides there into two temporal ridges, each of which extends anterolaterally on the posterior edge of the postorbital process of the frontal bone.

sedimentary rocks. These are rocks formed from particles derived from larger rock bodies or cool-condition chemical precipitation. They include such rocks as limestones, shales, sandstones, siltstones, claystones, mudstones, gypsum, and salt deposits.

Site. A place. In the context of this publication, the place from which the fossils were recovered.

species - A taxonomic rank lying between the lower-level subspecies and the higher-level genus. There are various definitions, but in all it is a population-level term referring to individuals connected by some manner of genetic similarity. This similarity may be the reproductive, behavioral, or morphological, depending on the definition. The plural also is species.

species, biological. A group of interbreeding natural populations that is reproductively isolated from other such groups.

species, morphological - A group of populations whose members are morphologically similar and separated by a morphological gap from other such populations.

stadial - A relatively cool interval with extensive glacial activity within the Pleistocene Age.

subspecies - A subspecies is an aggregate of phenotypically similar populations of a species inhabiting a geographic subdivision of the range of that species and differing taxonomically from other populations of that species.

supraorbital process of frontal - The process of the frontal bone on the top rim of the orbit, as in a rabbit.

tarsus - The ankle.

taxon - Any formally named taxonomic group of organisms. Thus Homo sapiens is a taxon; so is Mammalia. "Species" is not—it is a rank of the taxonomic hierarchy and does not denote a specific, named group of organisms. The plural of taxon is taxa.

temporal ridge (paired) - A curved, raised line on the side of the braincase marking the upper limit of attachment of the fascia of the temporal muscle. The temporal ridge is prominent on the parietal bone, frequently extends forward onto the frontal bone, and in some kinds of mammals extends backward onto the interparietal bone. When present, the sagittal crest is formed by the coalescence of the two temporal ridges.

tibia (plural, tibiae) - The inner and usually the larger of the two bones of the hind limb (leg) between the knee and the ankle.

Tooth formula - The number of teeth on one side of the upper and lower jaws. Usually given in the form: 3/3 1/1 4/4 3/3 = 44 with the numbers reduced if teeth are evolutionarily lost. Numbers above the diagonal refer to the teeth in one side of the upper jaws and those below to one side of the lower jaws. The teeth are given in the order of incisors, canines, premolars, and molars. Thus, in the example, there are 3 upper and 3 lower incisors, 1 upper and 1 lower canine, and so forth. The number after the equal sign gives the total number of teeth; since the formula is for one side, the total number is double that (in the example, 22 X 2 = 44).

anterolateral dentine tract - An area lacking enamel on the anterolateral portion of the lower first molar of some species of Neotoma.

Trans-Pecos Texas - The part of western Texas to the west of the Pecos River.

tree-ring - See dendrochronology

type locality - The place where a type specimen (the holotype) was obtained.

ungulate - Hoof-bearing mammals, including the Artiodactyla and Perissodactyla, among others.

unicuspid - Mammalian teeth having a single (or single major) cusp, thus somewhat cone-like. Used particularly for the single-cusped teeth posterior to the anterior incisors in shrews, but may also be used for canines or other types of teeth with a single cusp.

urococcyx - a skeletal element of anurans (frogs and relatives) apparently consisting of fusion of the sacrum and tail vertebrae. The portion that includes the expanded "wings" of the figure is the sacrum, while the rod-like structure is homologous with the vertebrate tail.
Urococcyx of Spea multiplicata

Wisconsin Age - The last age of the Pleistocene, running from about 90,000 to 10,000 BP.

zygomatic breadth - Greatest distance across zygomatic arches of cranium at right angles to the long axis of skull.