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CHIN—ANALYSES OF COPROLITES PRODUCED BY VERTEBRATESof locality and stratigraphic information is of criticalimportance. In many cases, coprolites have erodedout of their encasing sediments and are collected asfloat. Although such specimens contribute notablebaseline information about a given formation, theinformative value of coprolites is greatly enhancedwhen they are collected in situ and can be correctlyplaced within a detailed stratigraphic column.Mapping specimens in place will also indicatecoprolite orientation and density. Such taphonomicinformation contributes important information aboutthe environment of deposition.Photographic documentation of specimens isas useful for coprolite analysis as it is for researchon other fossils. Unfortunately, most coprolites arenot as strikingly photogenic as many skeletalfossils! Nevertheless, images of seeminglyamorphous coprolitic masses are quite usefulbecause they document the range of coprolite sizeand morphology, and help create search images forpaleontologists likely to encounter fossilized fecesin the field (Fig. 1). Such records become evenmore important when destructive analyses alter theoriginal form of a specimen. Photos should alwaysinclude a scale.If a coprolite specimen is very important orhas an unusually distinctive morphology, standardpaleontological molding and casting methods (seeGoodwin and Chaney, 1994) can be used toreplicate the external form. Care should be taken,however, if this technique is applied to fragilespecimens; some coprolites are composed of softmaterials that can be easily scratched or gouged(possibly obscuring paleobiologically informativeimpressions), or may absorb compounds appliedas separators or mold release agents. This techniqueshould not be used on highly fractured specimens.Non-destructive Analyses.—Intact coprolitespecimens can be characterized by morphology, size,and surface features. Although coprolites from manydifferent taxa can have similar traits, documentationof the physical characteristics of coprolite specimensis important because recurring features may revealdistinct morphological categories. Such forms maybe designated as coprolite morphotypes. One earlyclassification scheme differentiated spiralcoprolites into “heterpolar” or “amphipolar” types,depending on the spacing of coils along the longaxis of the specimen (Neumayer, 1904). Thissystem has been applied to other spiral coprolites,though there is debate as to whether thesemorphotypes have any taxonomic significance (e.g.Price, 1927; Zidek, 1980).Linear dimensions of coprolites (e.g., diameterand length) provide rough approximations of fecalsize, but volumetric measurements give much moreinformative assessments. Volume can be measuredin several ways. The volume of small, densespecimens can be determined by measuring waterdisplaced by submerged samples; porousspecimens should be allowed to absorb waterbefore displacement is measured. This approachcan also be applied to large, fractured specimensby using water displacement to calculate thedensity of small fragments; volume can then bedetermined by extrapolation after weighing theentire specimen (e.g., Chin et al., 1998). In a fewcases a coprolite may be so large and fractured thatit remains in the plaster jacket in which it wascollected (e.g., Fig. 1a), and cannot be accuratelyweighed. The volume of such specimens can beapproximated by visualizing the mass as beingcomposed of one or more geometric shapes whosevolumes can be calculated.When a large number of coprolites from agiven locality represents an unbiased sample,recurring size classes and other physicalcharacteristics may indicate specimens producedby a small number of taxa and/or age groups. Suchgroupings may be subtle, however. Edwards andYatkola (1974) analyzed 106 coprolites from theWhite River Formation and found no distinct sizeclasses within a continuum of coprolite diametersranging from 15 to 36 mm. But when the data wasre-analyzed using the mean diameter of in situcoprolites that occurred in small “clusters”(suggesting individual fecal deposits), they foundthree distinct size groups that may reflect the sizesof the carnivores that produced them. Correlatingcoprolite size with other physical attributes willrefine interpretations, though some features (suchas color and degree of flattening) probably provide45