Publication Date:
2024-04-22
Description:
Symbiotic species, living within or on the surface of host organisms, may evolve a
wide range of adaptations as a result of various selection pressures, host specificity
of the symbiont and the nature of the symbiosis. In tropical marine coral reef ecosystems, palaemonid shrimps (Crustacea: Decapoda: Caridea) live in association with at
least five different invertebrate phyla. Host switches between (distantly) related host
groups, and the thereby associated selection pressures were found to play a major
role in the diversification of these shrimp lineages, giving rise to various host-specific
adaptations. Two lineages of palaemonid shrimp, which have switched from an ectosymbiotic association towards endosymbiosis, are studied for their morphological
diversification and possible convergence. Special attention is given to the betweenphyla host switches involving ascidian and bivalve hosts, which are characteristic for
these lineages. Using landmark-based (phylo)morphospace analyses and Scanning
Electron Microscopy, the walking leg dactylus shape and the microstructures on these
dactyli are studied. No specific bivalve- or ascidian-associated morphotypes were
found, but morphological convergence in dactylus morphology was found in various
species within the two studied clades with similar host groups. In addition, multiple
lineages of bivalve-associated species appear to be morphologically diverging more
than their ascidian-associated relatives, with ‘intermediate’ morphotypes found near
host-switching events.
Keywords:
adaptive radiation
;
morphometrics
;
phylomorphospace
;
SEM-photography
;
symbiosis
Repository Name:
National Museum of Natural History, Netherlands
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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