The Ichnofacies Paradigm - Trace Fossils as Indicators of Sedimentary Environments - page 108

et al., 1994 ). The Brontopodus , Carichnium , and Pteraichnus ichnofacies are
restricted to Early Cretaceous clastic successions, Early Cretaceous carbonate
intervals, and Late Jurassic marine shoreline successions, respectively ( Hunt
and Lucas, 2007; Lockley and Meyer, 2000; Lockley et al., 1994, 2001 ). Other
Seilacherian ichnofacies have been established to cover a wide variety of con-
tinental habitats (see Buatois and M´ngano, 2011 , and the discussion in
Melchor et al., 2012 ). However, all of the tetrapod and vertebrate coprolite ich-
nofacies named prior to 2007 are limited in their temporal distribution, and in
some cases, in geographic distribution as well. Indeed, the Laoporus Ichnofa-
cies and Brasilichnium Ichnofacies are virtually indistinguishable from one
another and differentiated mainly on stratigraphic grounds owing to the age lim-
itations of the ichnofacies' namesakes (cf. Lockley et al., 1994; McIlroy,
2004b ). Hunt and Lucas (2007) referred to this as the biotaxonomic tradition
of ichnofacies. In this regard, the tetrapod ichnofacies framework has more
in common with the Seilacherian Cruziana biostratigraphy than it does with
the archetypal ichnofacies concept.
The Cruziana biostratigraphic paradigm, established by Seilacher (1970,
1991, 1994) , has been shown to be useful, in certain parts of the world, for bio-
stratigraphic zonation of otherwise non-fossiliferous successions. Similarly, the
original tetrapod “ichnofacies” ( Hunt et al., 1994, 1995, 1998; Lockley, 2007;
Lockley et al., 1994 ), while not comprising true ichnofacies, most certainly
exhibit biostratigraphic utility for continental successions that commonly con-
tain few, if any, body fossils ( M´ngano et al., 2012 ).
Most of the early tetrapod ichnofacies were downgraded to ichnocoenoses
by Hunt and Lucas (2007) , with the definitions of the remainder broadened to
include several former groupings. The remaining five ichnofacies include the
Batrachichnus Ichnofacies (characteristic of intertidal flats and alluvial plains),
the Brontopodus Ichnofacies (carbonate and clastic coastal plains and shore-
lines), the Characichnos Ichnofacies (shallow lacustrine), the Chelichnus Ich-
nofacies (eolian successions), and the Grallator Ichnofacies (marginal-
lacustrine settings). Although the Hunt and Lucas (2007) revision represents
a substantial improvement over the previous chaos of temporally and geograph-
ically restricted tetrapod ichnofacies, their amended ichnofacies still exhibit
significant temporal restrictions, albeit much less severe than previous exem-
plars. Unfortunately, these “new” tetrapod ichnofacies continue to differ from
true ichnofacies in terms of their taxonomic restriction. Ichnofacies, in the sense
they were intended (cf. Seilacher, 1953a,b ), are theoretical constructs encom-
passing ethologically distinct ichnocoenoses that are widely distributed, both
geographically and through geological time ( Bromley and Asgaard, 1991;
Buatois and M ´ ngano, 2011; Frey et al., 1990; Hunt and Lucas, 2007;
MacEachern et al., 2007a,b; Pemberton et al., 1992 ). Likewise, these ichnofa-
cies are not restricted to particular taxonomic groupings. The archetypal Seila-
cherian ichnofacies represent the activities of a wide variety of organisms,
including (but not

restricted to) arthropods, echinoderms, polychaetes,