19
amber) that is known for preserving microscopic details of small organisms
required for identifying parasites. They used the appropriate methodology for
examining the fossil which allows them to closely examine and discern fine
details required for identification (in this case, X-ray microcomputed tomography), and they subjected a comparable living specimen to the same examination
method to check if they obtained similar or comparable results to what was
found with the fossil.
Prospective palaeoparasitologists can take a pro-active approach to the study of
fossil parasites by examining fossils of potential hosts for signs of parasitism based
on what is known in extant parasite-host systems. As discussed above, extant fish
are known to host copepods, isopods, and monogenean parasites on various parts of
their body with some infecting their skin, fins, and eyes, while other are located
under the gill covers or within the body cavity. Therefore, well-preserved fish fossils
should be examined at those parts for remains of potential parasites using a combination of microscopy and microCT scans. Additionally, some host taxa and characteristics are associated with certain types of parasites. Among extant terrestrial
vertebrates, integumentary covering such as feathers or fur are associated with parasitic arthropods as they provide shelter for ectoparasites, therefore, well-preserved
fossil feathers and fur may also be a source for ectoparasite fossils which may be
revealed through careful examination, as suggested by Peñalver et al. (2017).
Likewise examining faecal samples is common practice in parasitology to determine the parasite communities of various animals, this can also be applied to coprolites which should be examined for parasite egg inclusions, as suggested by Chin
(2021) and Francischini et al. (2018).
Conversely, fossil parasites can also be used to infer aspects of their host’s
ecology which might not be evident solely through their fossil remains. For example, as discussed in the section pertaining to nematodes, the presence of pinworm
eggs as inclusions in coprolite can provide valuable insight into the ecology, physiology, and even social behaviour of the animal from which the coprolite originated. In a more general sense, because some parasites have complex life-cycles
and are transmitted via ingestion of specific prey animals, the presence of a parasite species (or their eggs in host faecal matter) can be an indicator of the host’s
diet. Thus, vertebrate palaeontologists should also be investigating fossil parasites
as their presence can reveal important information about the animals that they
lived on/in.
Beyond providing a better understanding of how parasitism evolved, fossil parasites can also provide a more complete picture of palaeoecosystems and the ecology
of extinct animals. Further research on fossil parasites will provide us with a new
understanding and appreciation for the roles that parasites played in ancient
ecosystems.
Acknowledgements I would like to thank Kenneth De Baets for inviting me to contribute to this
volume and his helpful comments and suggestions on the initial drafts of this chapter. The silhouettes for Figs. 1.1 and 1.2 were obtained from PhyloPic (http://phylopic.org/).
1 Parasites of Fossil Vertebrates: What We Know and What Can We Expect…
amber) that is known for preserving microscopic details of small organisms
required for identifying parasites. They used the appropriate methodology for
examining the fossil which allows them to closely examine and discern fine
details required for identification (in this case, X-ray microcomputed tomography), and they subjected a comparable living specimen to the same examination
method to check if they obtained similar or comparable results to what was
found with the fossil.
Prospective palaeoparasitologists can take a pro-active approach to the study of
fossil parasites by examining fossils of potential hosts for signs of parasitism based
on what is known in extant parasite-host systems. As discussed above, extant fish
are known to host copepods, isopods, and monogenean parasites on various parts of
their body with some infecting their skin, fins, and eyes, while other are located
under the gill covers or within the body cavity. Therefore, well-preserved fish fossils
should be examined at those parts for remains of potential parasites using a combination of microscopy and microCT scans. Additionally, some host taxa and characteristics are associated with certain types of parasites. Among extant terrestrial
vertebrates, integumentary covering such as feathers or fur are associated with parasitic arthropods as they provide shelter for ectoparasites, therefore, well-preserved
fossil feathers and fur may also be a source for ectoparasite fossils which may be
revealed through careful examination, as suggested by Peñalver et al. (2017).
Likewise examining faecal samples is common practice in parasitology to determine the parasite communities of various animals, this can also be applied to coprolites which should be examined for parasite egg inclusions, as suggested by Chin
(2021) and Francischini et al. (2018).
Conversely, fossil parasites can also be used to infer aspects of their host’s
ecology which might not be evident solely through their fossil remains. For example, as discussed in the section pertaining to nematodes, the presence of pinworm
eggs as inclusions in coprolite can provide valuable insight into the ecology, physiology, and even social behaviour of the animal from which the coprolite originated. In a more general sense, because some parasites have complex life-cycles
and are transmitted via ingestion of specific prey animals, the presence of a parasite species (or their eggs in host faecal matter) can be an indicator of the host’s
diet. Thus, vertebrate palaeontologists should also be investigating fossil parasites
as their presence can reveal important information about the animals that they
lived on/in.
Beyond providing a better understanding of how parasitism evolved, fossil parasites can also provide a more complete picture of palaeoecosystems and the ecology
of extinct animals. Further research on fossil parasites will provide us with a new
understanding and appreciation for the roles that parasites played in ancient
ecosystems.
Acknowledgements I would like to thank Kenneth De Baets for inviting me to contribute to this
volume and his helpful comments and suggestions on the initial drafts of this chapter. The silhouettes for Figs. 1.1 and 1.2 were obtained from PhyloPic (http://phylopic.org/).
1 Parasites of Fossil Vertebrates: What We Know and What Can We Expect…