Gut Contents as Direct Indicators for Trophic Relationships in the Cambrian Marine Ecosystem
Figure 5
Sedimentary ingesta within the gut of Ottoia prolifica
from the middle Cambrian Burgess Shale Formation. A–D, USNM 196195, three-dimensionally preserved gut contents, general view and thin section; gut material (C) is easily distinguished from the matrix (D) by its brown colour due to high organic content. Crystals (in white) are not specific to the gut and are observed elsewhere in the matrix though smaller and less concentrated; they are interpreted as sponge spicules [21]. E, F, ROM 61755a, isolated fragment of gut content seen in transverse section. G, H, ROM 61754, gut contents showing small skeletal fragments and undetermined elements embedded in sediment. I, J, ROM 61755a, transverse section through upper part of gut content; the uppermost thin layer possibly represent the gut wall. K, ROM 61755b, thin carbonaceous film overlying gut contents, possibly representing the gut wall. gc, gut contents; se, sediment; sf, skeletal fragment; ue, undetermined element. A–D, courtesy L. Wilson (see also [21]). A, G are light photographs; B and D were taken in transmitted light; E, F, H-K are scanning electron micrographs (K, back-scattered image). Scale bar: 5 mm for A; 2 mm for G; 500 µm for B, H; 100 µm for C, D; 50 µm for K; 10 µm for E, I; 5 µm for F; 2 µm for J.