Phylogeny and morphology of Himerometroidea (Echinodermata: Crinoidea) feather stars in Singapore

Authors

Shawne Goh, National University of Singapore
Zheng Bin Randolph Quek, National University of Singapore
Sze Hui Foo, National University of Singapore
Teresa Stephanie Tay, National University of Singapore
Charles Messing, Nova Southeastern UniversityFollow
Danwei Huang, National University of Singapore

Document Type

Article

Publication Title

Raffles Bulletin of Zoology

ISSN

0217-2445

Publication Date

2-14-2023

Keywords

biodiversity, COI, integrative taxonomy, ontogenetic variation, phylogenetic analysis, tropical coastal habitats

Abstract

Evaluating the diversity of crinoids (Echinodermata: Crinoidea) in Singapore accurately has been challenging due in part to inadequacies in crinoid taxonomy. Most species descriptions have neither incorporated morphological variation of juveniles into diagnostic characters nor analysed species’ molecular phylogenetic affinities. In this study, we performed detailed morphological examination and phylogenetic analyses of the mitochondrial cytochrome c oxidase subunit I marker on Himerometroidea crinoids collected from the Singapore Strait, and showed that specimens could not be reliably identified to species based on existing taxonomic descriptions. Specifically, juveniles identified as Heterometra spp. and Zygometra sp., and adults as H. cf. producta, solely based on morphological features were revealed to comprise three distinct species: Zygometra cf. comata, Heterometra schlegelii, and Dichrometra sp. The juveniles were found to have sizes smaller than the ranges given in existing descriptions, with considerable variabilities in traits that limited the utility of morphology for species taxonomy. Features contributing to misidentification of specimens and their application in past species diagnoses are discussed. Revised descriptions of these species, as well as the recently revised Homalometra crenulata, are also presented. More broadly, this study emphasises the need to revisit diagnoses of crinoid species according to various ontogenetic stages and to uncover more congruent morphological characters based on a robust molecular phylogeny.

DOI

10.26107/RBZ-2023-0008

Volume

71

First Page

92

Last Page

105

Comments

This research is supported by the Lee Kong Chian Natural History Museum, National University of Singapore.

NSUWorks Citation

Shawne Goh, Zheng Bin Randolph Quek, Sze Hui Foo, Teresa Stephanie Tay, Charles Messing, and Danwei Huang. 2023. Phylogeny and morphology of Himerometroidea (Echinodermata: Crinoidea) feather stars in Singapore .Raffles Bulletin of Zoology : 92 -105. https://nsuworks.nova.edu/occ_facarticles/1295.