Cryptic Diversity of the Eel Goby, GenusTaenioides(Gobiidae: Amblyopinae), in Japan

Abstract

The eel goby, genus Taenioides (Gobiidae: Amblyopinae), inhabits muddy bottoms of estuaries or shallow areas of seas in the Indo-Pacific Ocean. Among congeners, T. cirratus ( Blyth, 1860 ) has been thought to be distributed in Japan, but taxonomic confusions remain as to which scientific names are applicable to Japanese Taenioides species, or more fundamentally, how many Taenioides species are distributed in Japan, due in part to the rarity of this group in museum collections and the morphological similarity among species. To clarify the species diversity of the genus Taenioides in Japan, we conducted phylogenetic analysis on the basis of partial mitochondrial DNA sequences and morphological observation of more than 100 specimens. As a result, four distinct species were distinguished from each other, on the basis of both genetic divergences (2.9-5.7%, 16S rRNA gene) and morphological differences (i.e., degree of development of dermal folds on the head, numbers of barbels and vertebrae). Although the identifications of four species need additional verifications, they were identified as T. anguillaris, T. snyderi, T. gracilis and T. cf. kentalleni, and the species name T. cirratus does not seem to be appropriate to any of four detected species. Museum collections indicate that the two species, which are distributed in the main islands of Japan, were collected frequently and treated as a single species. The other two were each collected only from a single locality of Okinawa Island in this study, of which one seems to be uncommon worldwide as well.

Larval study revealed diversity and life‐history traits of crypto‐benthic eel gobies

“…kentalleni Murdy & Randall 2002, but they recognized that their identifications required verification with examinations of the type specimens. Murdy (2018) agreed with Kurita and Yoshino (2012) after examination of the type specimens of the four species. Three of the four species, T. anguillaris , T. gracilis and T. kentalleni , are distributed on Okinawa Island (Kurita & Yoshino, 2012).…”

“…We examined three larval specimens and found that their dorsal‐, anal‐ and pectoral‐fin‐ray counts are within the ranges of those established for T. snyderi and T. gracilis in Koreeda and Motomura (2021), Kurita and Yoshino (2012), and Miyahira and Tachihara (2022) (Tables 6–8). The dorsal‐ and anal‐fin‐ray counts are almost the same as those established for the paralectotype of T. snyderi and holotype of T. gracilis (total dorsal‐fin elements, 53–54 in larvae vs .…”

“…We examined three larval specimens and found that their dorsal-, anal-and pectoral-fin-ray counts are within the ranges of those established for T. snyderi and T. gracilis in Koreeda and Motomura (2021), Kurita and Yoshino (2012), and Miyahira and Tachihara (2022) (Tables 6-8). Kurita and Yoshino (2012).…”

Differences in conservation candidate tidal rivers by cross‐taxon analysis in the Japanese temperate zone

“…As Leucopsarion petersii only appears in tidal rivers during spawning season and Acanthogobius hasta only appears during the juvenile period, these species were also excluded from the analysis. Although there are four Taenioides species in Japan (Kurita & Yoshino, 2012; Murdy, 2018), these are taxonomically confused with each other. Therefore, they were treated as one species, Taenioides cirratus , in accordance with the Ministry of the Environment (2018).…”

Fishes of Gobiidae Family, Recorded from the Rivers and Estuaries of Bangladesh: Morphometric and Meristic Studies

“…Although the identifications of four species need additional verifications, they were identified as T. anguillaris, T. snyderi, T. gracilis and T. cf. kentalleni, and the species name T. cirratusdoes not seem to be appropriate to any of four detected species (Kurita and Yoshino 2012).…”