Parasites in the Fossil Record: A Cretaceous Fauna with Isopod-Infested Decapod Crustaceans, Infestation Patterns through Time, and a New Ichnotaxon

Abstract

Parasites are common in modern ecosystems and are also known from the fossil record. One of the best preserved and easily recognisable examples of parasitism in the fossil record concerns isopod-induced swellings in the branchial chamber of marine decapod crustaceans. However, very limited quantitative data on the variability of infestation percentages at the species, genus, and family levels are available. Here we provide this type of data for a mid-Cretaceous (upper Lower Cretaceous, upper Albian) reef setting at Koskobilo, northern Spain, on the basis of 874 specimens of anomurans and brachyurans. Thirty-seven specimens (4.2%), arranged in ten species, are infested. Anomurans are more heavily infested than brachyurans, variability can be high within genera, and a relationship may exist between the number of specimens and infestation percentage per taxon, possibly suggesting host-specificity. We have also investigated quantitative patterns of infestation through geological time based on 88 infested species (25 anomurans, 55 brachyurans, seven lobsters, and one shrimp), to show that the highest number of infested species can be found in the Late Jurassic, also when corrected for the unequal duration of epochs. The same Late Jurassic peak is observed for the percentage of infested decapod species per epoch. This acme is caused entirely by infested anomurans and brachyurans. Biases (taphonomic and otherwise) and causes of variability with regard to the Koskobilo assemblage and infestation patterns through time are discussed. Finally, a new ichnogenus and -species, Kanthyloma crusta, are erected to accommodate such swellings or embedment structures (bioclaustrations).

150 million years old isopods on fishes: a possible case of palaeo-parasitism

“…Parasites are ubiquitous and abundant in all ecosystems and in all groups of living forms (e.g. Klompmaker et al 2014).…”

Taxonomy and palaeoecology of a decapod crustacean assemblage from the Oxfordian of Stránská skála (Southern Moravia, Czech Republic)

“…-Bopyriform swellings (as termed by Wienberg Rasmussen et al 2008), which typically occur on the branchial regions, were recently named Kanthyloma crusta by Klompmaker et al (2014). These swellings are known from many Upper Jurassic decapod assemblages (Bachmayer 1948, Houša 1963, Radwański 1972, Wienberg Rasmussen et al 2008, Robins et al 2012, Klompmaker et al 2014.…”

“…The sample, however, is too small to draw any conclusions regarding the preference for the left or right branchial side for infestation. Based on statistical data from the Albian of Koskobilo, Spain, Klompmaker et al (2014) concluded that there is no statistical preference for either the left or right branchial side for infestation on the assemblage level.…”

“…For comparison, Bachmayer (1955) reported the rate of infestation to be 2% out of 3 000 decapod specimens from the Tithonian of Ernstbrunn (Austria), Houša (1963) reported 3.82% out of 890 specimens from the Tithonian of Štramberk (Czech Republic) and Radwański (1972) reported less than 1.4% out of more than 500 specimens. For Cretaceous assemblages the rate of infestation seems to be comparable; for instance Klompmaker et al (2014) noted that 4.2% out of 874 decapod specimens from the Albian of Koskobilo quarry (Spain) were infected. It should, however, be noted that not all species from the studied assemblages possess swellings, but rather there is a preference for certain taxa.…”

“…It should, however, be noted that not all species from the studied assemblages possess swellings, but rather there is a preference for certain taxa. At the higher taxonomic level, galatheoid specimens usually are more afflicted than brachyuran families (Klompmaker et al 2014). From Stránská skála, however, no infested galatheoids are known.…”