A newly discovered radiation of endoparasitic gastropods and their coevolution with asteroid hosts in Antarctica

Kara K.S. Layton, Greg W. Rouse, Nerida G. Wilson

Research output: Contribution to journalArticle

Abstract

Background: Marine invertebrates are abundant and diverse on the continental shelf in Antarctica, but little is known about their parasitic counterparts. Endoparasites are especially understudied because they often possess highly modified body plans that pose problems for their identification. Asterophila, a genus of endoparasitic gastropod in the family Eulimidae, forms cysts in the arms and central discs of asteroid sea stars. There are currently four known species in this genus, one of which has been described from the Antarctic Peninsula (A. perknasteri). This study employs molecular and morphological data to investigate the diversity of Asterophila in Antarctica and explore cophylogenetic patterns between host and parasite. Results: A maximum-likelihood phylogeny of Asterophila and subsequent species-delimitation analysis uncovered nine well-supported putative species, eight of which are new to science. Most Asterophila species were found on a single host species, but four species were found on multiple hosts from one or two closely related genera, showing phylogenetic conservatism of host use. Both distance-based and event-based cophylogenetic analyses uncovered a strong signal of coevolution in this system, but most associations were explained by non-cospeciation events. Discussion: The prevalence of duplication and host-switching events in Asterophila and its asteroid hosts suggests that synchronous evolution may be rare even in obligate endoparasitic systems. The apparent restricted distribution of Asterophila from around the Scotia Arc may be an artefact of concentrated sampling in the area and a low obvious prevalence of infection. Given the richness of parasites on a global scale, their role in promoting host diversification, and the threat of their loss through coextinction, future work should continue to investigate parasite diversity and coevolution in vulnerable ecosystems.

Original languageEnglish
Article number180
JournalBMC Evolutionary Biology
Volume19
Issue number1
DOIs
Publication statusPublished - 18 Sep 2019

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coevolution
asteroid
gastropod
Antarctica
Gastropoda
parasite
parasites
endoparasite
host use
Agrotis
cyst
endoparasites
Asteroidea
phylogeny
artifact
radiation
continental shelf
invertebrate
phylogenetics
invertebrates

Cite this

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title = "A newly discovered radiation of endoparasitic gastropods and their coevolution with asteroid hosts in Antarctica",
abstract = "Background: Marine invertebrates are abundant and diverse on the continental shelf in Antarctica, but little is known about their parasitic counterparts. Endoparasites are especially understudied because they often possess highly modified body plans that pose problems for their identification. Asterophila, a genus of endoparasitic gastropod in the family Eulimidae, forms cysts in the arms and central discs of asteroid sea stars. There are currently four known species in this genus, one of which has been described from the Antarctic Peninsula (A. perknasteri). This study employs molecular and morphological data to investigate the diversity of Asterophila in Antarctica and explore cophylogenetic patterns between host and parasite. Results: A maximum-likelihood phylogeny of Asterophila and subsequent species-delimitation analysis uncovered nine well-supported putative species, eight of which are new to science. Most Asterophila species were found on a single host species, but four species were found on multiple hosts from one or two closely related genera, showing phylogenetic conservatism of host use. Both distance-based and event-based cophylogenetic analyses uncovered a strong signal of coevolution in this system, but most associations were explained by non-cospeciation events. Discussion: The prevalence of duplication and host-switching events in Asterophila and its asteroid hosts suggests that synchronous evolution may be rare even in obligate endoparasitic systems. The apparent restricted distribution of Asterophila from around the Scotia Arc may be an artefact of concentrated sampling in the area and a low obvious prevalence of infection. Given the richness of parasites on a global scale, their role in promoting host diversification, and the threat of their loss through coextinction, future work should continue to investigate parasite diversity and coevolution in vulnerable ecosystems.",
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A newly discovered radiation of endoparasitic gastropods and their coevolution with asteroid hosts in Antarctica. / Layton, Kara K.S.; Rouse, Greg W.; Wilson, Nerida G.

In: BMC Evolutionary Biology, Vol. 19, No. 1, 180, 18.09.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A newly discovered radiation of endoparasitic gastropods and their coevolution with asteroid hosts in Antarctica

AU - Layton, Kara K.S.

AU - Rouse, Greg W.

AU - Wilson, Nerida G.

PY - 2019/9/18

Y1 - 2019/9/18

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AB - Background: Marine invertebrates are abundant and diverse on the continental shelf in Antarctica, but little is known about their parasitic counterparts. Endoparasites are especially understudied because they often possess highly modified body plans that pose problems for their identification. Asterophila, a genus of endoparasitic gastropod in the family Eulimidae, forms cysts in the arms and central discs of asteroid sea stars. There are currently four known species in this genus, one of which has been described from the Antarctic Peninsula (A. perknasteri). This study employs molecular and morphological data to investigate the diversity of Asterophila in Antarctica and explore cophylogenetic patterns between host and parasite. Results: A maximum-likelihood phylogeny of Asterophila and subsequent species-delimitation analysis uncovered nine well-supported putative species, eight of which are new to science. Most Asterophila species were found on a single host species, but four species were found on multiple hosts from one or two closely related genera, showing phylogenetic conservatism of host use. Both distance-based and event-based cophylogenetic analyses uncovered a strong signal of coevolution in this system, but most associations were explained by non-cospeciation events. Discussion: The prevalence of duplication and host-switching events in Asterophila and its asteroid hosts suggests that synchronous evolution may be rare even in obligate endoparasitic systems. The apparent restricted distribution of Asterophila from around the Scotia Arc may be an artefact of concentrated sampling in the area and a low obvious prevalence of infection. Given the richness of parasites on a global scale, their role in promoting host diversification, and the threat of their loss through coextinction, future work should continue to investigate parasite diversity and coevolution in vulnerable ecosystems.

KW - Antarctica

KW - Asteroidea

KW - Asterophila

KW - Coevolution

KW - Endoparasites

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U2 - 10.1186/s12862-019-1499-8

DO - 10.1186/s12862-019-1499-8

M3 - Article

VL - 19

JO - BMC Evolutionary Biology

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SN - 1471-2148

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ER -