Epibionts are uniquely valuable in their ability to constrain paleoecological hypotheses about their own as well as their host's behavior and environment. Rarely preserved epizoic bryozoans are here reported on fossil crabs from the Miocene Mishan Formation in the Zagros Basin of southwestern Iran. One-hundred-thirty-eight decapod crustaceans were recovered from the upper marly member of the Mishan Formation. Of those, seven decapods (5%) were fouled by bryozoans. Of these seven decapods, five had bryozoans growing attached to the cuticle of the hard outer surface of the exoskeleton of the host crabs and thus fouled while the host crab was potentially alive. Forty percent of the bryozoan colonies occurred on the host crab's dorsal carapace, and 60% were found on chelipeds. On average, 30% of the surface area of the host crabs' fouled skeletal components were covered by bryozoan colonies. The brachyurans were mostly leucosiids, including Leucosia persica and Myra sp. The bryozoans were all cheilostomes and included Acanthodesia sp., Thalamoporella sp., and an indeterminate ascophoran. These bryozoans are all the first reported occurrences in the Mishan Formation. The low incidence of crabs fouled by bryozoans is attributed to preservational bias. The results from this study are compared to those of fossil and extant host crabs reported in the literature. The bryozoan-crab relationship documented here is best described as commensalism.

Vertebrate tracks are linked to the depositional environment where they were formed. Several studies hypothesized a paleoenvironmental control on vertebrate track ichnocoenoses, although this issue was never analyzed thoroughly. A new study of the sedimentology and tetrapod ichnology of two key stratigraphic sections in the Pizzo del Diavolo Formation of the lower Permian continental Orobic Basin of Southern Alps (Italy) tested the link between tetrapod ichnocoenoses and depositional environment. Behavior, taphonomy, and ichnocoenoses of three different lithozones (P-PDV, U-PDVa, U-PDVb) were analyzed and compared, two new census methods for tetrapod tracks were tested (“track/slab” and “weighting size”) and the first was applied to our specimen sample. The possible biostratigraphic meaning of track occurrences/relative proportions were discussed and excluded. Results indicate a predominance of the ichnogenus Erpetopus in a distal floodplain environment (P-PDV), a diverse ichnocoenosis in a proximal floodplain environment (U-PDVa), and a predominance of the ichnogenus Dromopus in a scarcely diverse ichnocoenosis in a floodplain/marginal lacustrine environment (U-PDVb). This encourages further detailed studies on tetrapod track paleoecology, in order to refine and give utility to the concept of tetrapod ichnofacies.

Molluscan taphonomic patterns below the sediment-water interface in three freshwater shallow lakes from the Southeastern Pampa Plain, Argentina (Nahuel Rucá, Las Mostazas, and Los Carpinchos), were analyzed in order to explore the taphonomic alteration suffered by mollusks with depth and determine if this taphonomic alteration varied locally within lakes or between them. Short cores (approximately 30 cm) from littoral environment as well as open water were sampled in each lake. Nine mollusk species were identified: Heleobia parchappii, H. australis, Biomphalaria peregrina, Uncancylus concentricus, Musculium argentinum, Drepanotrema kermatoides, Succinea meridionalis, Antillorbis nordestensis, and Pomacea canaliculata. The highest percentage of moisture, organic matter and carbonates as well as less alkaline pH were recorded at the top of the cores and in littoral environments, indicating less favorable conditions for preservation. Results suggest that the taphonomically active zone occupies the first 10 cm below the sediment-water interface.

Patterns of sclerobiont encrustation constitute important data in studies of paleosynecology and autecology, yet methods used to collect this information are not standardized. The variation among different methods may be attributed to the need for uniquely designed methods applied to address a specific question. As a result, comparisons between sclerobiont studies are cumbersome, results are sometimes contradictory, and the interpretive value among published results is low. A comparison of techniques commonly used for computing sclerobiont abundance and distribution upon host substrates revealed that the simplest measure of abundance, numerical abundance, under-reported large colonial organisms and over-reported small colonial and solitary organisms when compared to calculated baseline values obtained from digitized photos in ArcGIS. Spatial abundance methods, also examined, show areal percent coverage estimation over-reports total encrustation, but not substantially.

Methods commonly used to determine sclerobiont abundance, including spatial, numerical, and frequency of encrustation techniques, were applied to a sample set of the relatively flat, concavo-convex Ordovician brachiopod Rafinesquina. Spatial estimation was the only method to preserve rank abundance calculated by ArcGIS. Frequency of encrustation ranked nearly half the sclerobionts differently than the calculated values in terms of abundance. Most spatially based grid overlay methods produced different abundance rankings; grid overlays with fewer grid sections better reflected baseline values. Different methods employed in reporting sclerobiont encrustation patterns introduce biases unique to each method. Understanding the biases inherent to each method allows more highly resolved interpretations, and promotes more consistent approaches to sclerobiont analysis.