Paleontology

The mode of preservation represented by fossil gastropods whose shells are now composed of calcite

Replacement by silica

A two-dimensional impression of the features on the inside of a shell that has now leached away

External mold

The mode of preservation of some Siberian and Yukon mammoths that preserved soft tissues and even DNA

Freezing

The probable originator of small, circular, counter-sunk holes in bivalve shells

Predatory snails radula (tongue drill)

The behaviour shown by horizontal burrows that exhibit horizontal spreiten, fecal pellets, or complex branching

Feeding traces

The probable behaviour of trace fossils that exhibit vertical repetition or vertical spreiten

Escape burrows

A phylum of colonial lophophorates with a calcareous or chitinous skeleton

Bryozoan

A salinity regime, typical of estuaries and deltas, that severely limits the diversity and size of shelled organisms

Mesohaline

An order of Ordovician-Silurian colonial, pelagic, marine organisms whose carbonized remains characterize many black shales

Graptolites (grapling hook)

The most important function of trilobite genal spines

Defence from predation

A problem overcome by siphuncular deposits, cameral deposits and planispiral coiling

Buoyancy-stability problem

An evolutionary event in marine molluscs in response to the post-Paleozoic increase in shell-crushing, shell-peeling, and shell-boring predators

Marine mesozoic revolution

The type of eye in phacopid tribolites that closely mimics the structure of an ideal aplantic lens

Schizochroal (schizophrenic choral)

The most successful class of echinoderms in the Modern Fauna

Astroidea (astroid - ea)

The ciliated feeding and respiratory organ that characterizes brachiopods and bryozoans

Lophophores (Lo - pho - phores)

A cross-plot of morphological attributes, on which the number of successful forms in contoured to show adaptive peaks and valleys

Fitness landscapes

The hydraulic system used by echinoderms for locomotion, feeding and respiration

Water vascular system

The Canadian province that contains Cambrian tribolites from Laurentia in the west of the province and Cambrian trilobites from Baltica in the east

New Brunswick

The most important function of small-scale ornamentation on ammonites

Creates turbulence to reduce drag (analogous to dimples on a golf ball)

The sister group to the chordates, represented by five living classes and fifteen extinct classes of exclusively marine invertebrates

Graptolites

The most common mode of preservation of Paleozoic wood, arthropods, and graptolites

Altered hard parts -- carbonization

A general term to encompass all the changes that occur between the death of an organism and its discovery as a fossil

Taphonomy

A class of bivalved crustaceans that were common in hypersaline environments in the Kingston area

Ostracod? (Ostra - cod)

A general term for aqueous environments in which there is enough light for vision but not for photosynthesis

Disphotic zone

The most important plantonic, filter-feeding group in Ordovisian seas of the Kingston area

Graptolites

The probable producer of circular borings in bivalve shells

Gastropods

A type of lens, independently discovered in 1690 by Descartes and Huygens, that closely approximates the type of lens in the eye of a phacopid trilobite

Aplantic (A - plan - tic)

A juvenile stage of trilobite ontogeny, in which the trilobite contains less than the adult number of segments

Meraspid period (Meras - pid)

The ciliated feeding and respiratory organ that characterizes brachiopods and bryozoans

Lophophores (Lo - pho - phores)

Lentil-sized pelagic gastropods that first appeared in the Eocene and are abundant in modern seas

Pteropods (Tero - pods)

A term, commonly used in describing fossil sponges, where groups within different orders or even classes have evolved similar morphology due to convergence

Convergent evolution

The time of maximum disparity of the echinoderms, as indicated by the number of fossil classes

17 classes seen after the Great Ordovician Radiation

The main environment of modern stalked crinoids

Deep sea environments

An extinct group of aqueous, scorpion-like chelicerates that gradually changed their environment preference from normal marine in the Ordovician to exclusively fresh-water by the Permian

Eurypterid (Eury - terid)

A tooth-like microfossil that can be used to determine thermomaturation (burial depth and temperature)

Conodont (cono - DONT!)

A general term for corals that host symbiotic algae in their tissues

Photosymbionts

The only molluscan class with more fossil species than living species

Cephalopods

A phylum of colonial lophophorates with a calcareous or chitinous skeleton

Bryozoan

The earliest stage of trilobite ontogeny, in which the trilobite is a small, rounded disk

Protaspid period (Protas - pid)

The eye structure of agnostid trilobites

Blind

A general term to refer to fossil assemblages with abundant preservation of soft tissues

Unaltered soft parts

The most nearshore of the Silurian brachiopod communities in the Welsh Borderlands (typified by a brachiopod genus that also occurs in the Ordovician of the Kingston area)

Strophomenia (Stropho - menia)

A three-dimensional infill of a leached shell that preserves only internal features

Steinkern or core

A general term for marine environments in which free oxygen is available but limited (0.1-1ml/L)

Disoxic

How the discoid foraminiferan Nummulites grew so big

Photosymbionts (symbiotic relationship with algae)

A group of Ediacaran organisms characterized by modular construction using tubular (“soda straw”) elements

Erniettomorphs (Ernie - ttomorphs)

An ichnofacies dominated by deep, permanent burrows that were lined for stability

Glossifungites (Glossi - fungites)

An iconic Ediacaran soft-bodied fossil that shows evidence of motility and probably represents a stem-group bilaterian

Dickinsonia

An arthropod with strange claws and remarkable eyesight that was the top predator of the Burgess Shale

Anomalocaris (Anomal - ocaris)

The likely feeding strategy of large Ordovician gastropods such as Maclurites

Suspension feeder

An ecological strategy, particularly well illustrated by paleozoic crinoids and ediacaran rangeomorphs, in which different species sub-divide food resources by filter feeding at different levels above the sea floor

Suspension feeding through a tiered sea bottom

A group of Paleozoic, pelagic, filter-feeding organisms that were probably related to Rhadbopleura and other modern hemichoordates

Graptolites

A deep sea ichnofacies characterized by abundant grazing and farming burrows

Nereites

A grade of calcified sponges that built reef mounds in the early Cambrian

Archaeocyathans (Archaeo - cyathans)

In the punctuated equilibrium model, the interval during which the fossil species does not show any morphological change

Homeostasis

The articulate brachiopod order that is the most common and diverse in modern seas

Rhynchonellida (Rhyn - chon - ellida)

A general term to refer to lithified substrates characterized by boring and encrusting organisms

Hard ground

A limiting factor that increased in abundance at the end of the Gaskiers glaciation 580 million years ago, permitting the evolution of large eukaryotes

Oxygen

The coral order that formed reefs in the Cenozoic

Scleractinion (Scler - act - inion)

The oldest definite evidence of arthropods in the fossil record

Exoskeleton and Ecdysis preservation