231
© The Author(s) 2021
K. De Baets, J. W. Huntley (eds.), The Evolution and Fossil Record of Parasitism,
Topics in Geobiology 49, https://doi.org/10.1007/978-3-030-42484-8_7
Chapter 7
Fossil Constraints on the Timescale
of Parasitic Helminth Evolution
Kenneth De Baets, Paula Dentzien-Dias, G. William M. Harrison,
D. Timothy J. Littlewood, and Luke A. Parry
Abstract The fossil record of parasitic helminths is often stated to be severely
limited. Many studies have therefore used host constraints to constrain molecular
divergence time estimates of helminths. Here we review direct fossil evidence for
several of these parasitic lineages belong to various phyla (Acanthocephala,
Annelida, Arthropoda, Nematoda, Nematomorpha, Platyhelminthes). Our compilation shows that the fossil record of soft-bodied helminths is patchy, but more diverse
than commonly assumed. The fossil record provides evidence that ectoparasitic helminths (e.g., worm-like pentastomid arthropods) have been around since the early
Paleozoic, while endoparasitic helminths (cestodes, nematodes) arose at least during, or possibly even before the late Paleozoic. Nematode lineages parasitizing terrestrial plant and animal hosts have been in existence at least since the Devonian and
Triassic, respectively. All major phyla (Acanthocephala, Annelida, Platyhelminthes,
Nematoda, Nematomorpha) had evolved endoparasitic lineages at least since the
Mesozoic. Interestingly, although parasitism is considered derived within Metazoa,
the oldest evidence for Nematoda and Platyhelminthes includes body fossils of parasitic representatives. Furthermore, the oldest fossil evidence of these parasitic linK. De Baets ()
Geozentrum Nordbayern, Friedrich-Alexander University Erlangen-Nürnberg,
Erlangen, Germany
e-mail: kenneth.debaets@fau.de
P. Dentzien-Dias
Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
e-mail: pauladentzien@furg.br
G. W. M. Harrison
Naturalis Biodiversity Center, Leiden, Netherlands
e-mail: william.harrison@naturalis.nl
D. T. J. Littlewood
The Natural History Museum, London, UK
e-mail: t.littlewood@nhm.ac.uk
L. A. Parry
Department of Earth Sciences, University of Oxford, Oxford, UK
e-mail: luke.parry@seh.ox.ac.uk
© The Author(s) 2021
K. De Baets, J. W. Huntley (eds.), The Evolution and Fossil Record of Parasitism,
Topics in Geobiology 49, https://doi.org/10.1007/978-3-030-42484-8_7
Chapter 7
Fossil Constraints on the Timescale
of Parasitic Helminth Evolution
Kenneth De Baets, Paula Dentzien-Dias, G. William M. Harrison,
D. Timothy J. Littlewood, and Luke A. Parry
Abstract The fossil record of parasitic helminths is often stated to be severely
limited. Many studies have therefore used host constraints to constrain molecular
divergence time estimates of helminths. Here we review direct fossil evidence for
several of these parasitic lineages belong to various phyla (Acanthocephala,
Annelida, Arthropoda, Nematoda, Nematomorpha, Platyhelminthes). Our compilation shows that the fossil record of soft-bodied helminths is patchy, but more diverse
than commonly assumed. The fossil record provides evidence that ectoparasitic helminths (e.g., worm-like pentastomid arthropods) have been around since the early
Paleozoic, while endoparasitic helminths (cestodes, nematodes) arose at least during, or possibly even before the late Paleozoic. Nematode lineages parasitizing terrestrial plant and animal hosts have been in existence at least since the Devonian and
Triassic, respectively. All major phyla (Acanthocephala, Annelida, Platyhelminthes,
Nematoda, Nematomorpha) had evolved endoparasitic lineages at least since the
Mesozoic. Interestingly, although parasitism is considered derived within Metazoa,
the oldest evidence for Nematoda and Platyhelminthes includes body fossils of parasitic representatives. Furthermore, the oldest fossil evidence of these parasitic linK. De Baets ()
Geozentrum Nordbayern, Friedrich-Alexander University Erlangen-Nürnberg,
Erlangen, Germany
e-mail: kenneth.debaets@fau.de
P. Dentzien-Dias
Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
e-mail: pauladentzien@furg.br
G. W. M. Harrison
Naturalis Biodiversity Center, Leiden, Netherlands
e-mail: william.harrison@naturalis.nl
D. T. J. Littlewood
The Natural History Museum, London, UK
e-mail: t.littlewood@nhm.ac.uk
L. A. Parry
Department of Earth Sciences, University of Oxford, Oxford, UK
e-mail: luke.parry@seh.ox.ac.uk