Synagrops japonicus (Doderlein, 1883) Van der Laan et al., 2023

Mediodia, Dominique P., Lin, Chia-Hao Chang Chien-Hsiang, Ho, Hsuan-Ching & Přikryl, Tomáš, 2024, Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (20), pp. 141-149 : 12-14

Synonymy of Synagrops japonicus and Synagrops bellus

The genus Synagrops Günther, 1887 under the family Acropomatidae proposed by Johnson (1984) previously contained 12 species. Schwarzhans and Prokofiev (2017) revised the species assignment of Synagrops which now only includes S. japonicus and S. bellus based on distinguishable characters, such as the smooth pelvic and dorsal fin, two anal spines, numerous denticles on the ectopterygoid, presence of basioccipital fossa, posterior openings of the myodome, and subrectangular otolith. Most authors agreed that these two recognized species represent the genus Synagrops . However, recent studies considered Synagrops under the family Synagropidae Smith, 1961 ( Ghedotti et al. 2018; Serena et al. 2022; Smith et al. 2022), which includes three other genera, namely Parascombrops , Caraibops , and Kaperangus (Van der Laan et al. 2023) .

Hypoclydonia bella Goode and Bean, 1896 is the senior synonym of S. bellus Goode and Bean, 1892 , while Melanostoma japonicum Döderlein, 1883 is the senior synonym and S. natalensis Gilchrist, 1922 is the junior synonym of S. japonicus ( Döderlein, 1883) (Van der Laan et al. 2023) . The two species recognized under the genus Synagrops , S. japonicus and S. bellus , are synonymized in this study, agreeing with the report of Heemstra et al. (2022). Based on the original description of S. bellus ( Goode and Bean, 1896) and specimens from the MCZ museum collection, it does not differ in its morphological characteristics from S. japonicus ( Table 1), and other works also highlighted the close morphological relationship between S. japonicus and S. bellus ( Mochizuki 1989; Mejía et al. 2001).

Our results showed no differences in the morphological and meristic characters of S. japonicus and S. bellus . Osteological description, as presented through radiographs, showed the identical characteristics of the posterior openings of the myodome and basioccipital fossa of both species ( Fig. 7 ). It is also worth mentioning that the otoliths of S. japonicus and S. bellus appear very similar ( Rivaton and Bourret 1999; Brenha-Nunes et al. 2016). Moreover, the molecular analyses showed the cluster of S. japonicus and S. bellus , suggesting the synonymy of both species. Hannachi et al. (2015) and Serena et al. (2022) also emphasized the need to conduct further studies to determine the geographic distribution of S. japonicus after it was reported in the Mediterranean Sea, believed to be introduced by ballast waters. In such a case, S. japonicus would have a much wider species distribution, including the East Atlantic. In conclusion, the genus Synagrops only includes S. japonicus (syn. S. bellus ) and S. atrumoris .

Figures

Fig. 7. Prootic (A–D), exoccipital (E–H), and basioccipital (I–L) of Synagrops atrumoris sp. nov., non-type, CHLP2000314, 178.9 mm SL, and Synagrops japonicus (Döderlein, 1883), non-type, CHLP2000310, 174.2 mm SL. The actual images are presented in figure S2. Scale bars = 5 mm.