DNA barcoding and morphological analyses revealed validity of Diadema clarki Ikeda, 1939 (Echinodermata, Echinoidea, Diadematidae)

By

Chow, Seinen
Konishi, Kooichi
Mekuchi, Miyuki
Tamaki, Yasuji
Nohara, Kenji
Takagi, Motohiro
Niwa, Kentaro
Teramoto, Wataru
Manabe, Hisaya
Kurogi, Hiroaki
Suzuki, Shigenori
Ando, Daisuke
Jinbo, Tadao
Kiyomoto, Masato
Hirose, Mamiko
Shimomura, Michitaka
Kurashima, Akira
Ishikawa, Tatsuya
Kiyomoto, Setuo

Type

Article

Date of Publication

2016

Original Publication

ZooKeys

Volume

585

Pages

1-16

Subjects

Diadema clarki , Diadematidae , DNA barcoding , Echinoidea

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/zookeys.585.8161

 

Abstract

A long-spined sea urchin Diadema-sp reported from Japanese waters was genetically distinct from all known Diadema species, but it remained undescribed. Extensive field surveys in Japan with molecular identification performed in the present study determined five phenotypes (I to V) in Diadema-sp according to the presence and/or shape of a white streak and blue iridophore lines in the naked space of the interambulacral area. All phenotypes were distinct from Diadema setosum (Leske, 1778) and Diadema savignyi (Audouin, 1829), of which a major type (I) corresponded to Diadema clarki Ikeda, 1939 that was questioned and synonymized with D. setosum by Mortensen (1940). The holotype of D. clarki has not been found, but three unlabeled dried tests of Diadema were found among Ikeda’s original collection held in the Kitakyushu Museum of Natural History and Human History, Fukuoka, Japan. A short mtDNA COI fragment (ca. 350bp) was amplified from one of the tests, and the nucleotide sequence determined (275bp) was nearly identical with that of Diadema-sp. Arrangements of the primary tubercles on the coronal plates in Diadema-sp and the museum specimen also conformed with D. clarki, indicating that Diadema-sp is identical to D. clarki and a valid species. Narrow latitudinal distribution (31°N to 35°N) of D. clarki in Japan was observed, where it co-existed with abundant D. setosum and rare D. savignyi. No D. clarki was found in the southern islands in Japan, such as Satsunan Islands to Ryukyu Islands and Ogasawara Island, where D. setosum and D. savignyi were commonly observed.