Luciogobius platycephalus, Shiogaki & Dotsu, 1976

Koreeda, Reo, Maeda, Ken & Motomura, Hiroyuki, 2023, A new subtropical species of goby of the genus Luciogobius (Gobiidae) from southwestern Japan, Zootaxa 5361 (3), pp. 390-408 : 391

The Luciogobius platycephalus complex sensu Shibukawa et al. (2019)

Morphological characters. Species of the Luciogobius platycephalus complex possess the following combination of characters: second vertebrae with pleural ribs (sometimes one side absent); anus to anal-fin origin (AAA) longer than half body depth at anus to anal-fin origin; dorsal-fin origin just above or behind anterior 1/3 part of anal-fin base; total dorsal-fin rays usually 10–12; pectoral fin with 2–7 free uppermost rays; posterior margin of pectoral-fin membrane between each fin ray relatively concave; anteriormost pterygiophore of anal fin inserted between second to fourth haemal spine.

Species included in the Luciogobius platycephalus complex: Luciogobius griseus n. sp., Luciogobius platycephalus Shiogaki & Dotsu, 1976 , Luciogobius sp. 7 sensu Shibukawa et al. (2019).

Remarks. Members of the L. platycephalus complex can be distinguished from other species complexes by the presence of pleural ribs on the second vertebra, except the L. grandis complex sensu Shibukawa et al. (2019) ( Shibukawa et al., 2019; this study). The latter complex differs from the L. platycephalus complex by having 12–18 (usually more than 13) dorsal-fin rays, AAA shorter than half the body depth at the anus to anal-fin origin [except for Luciogobius sp. 6 sensu Shibukawa et al. (2019)], dorsal-fin origin just vertical through or slightly posterior to anal-fin origin (except for Luciogobius sp. 6 ), and the anteriormost anal-fin pterygiophore inserted between the first and second haemal spines [sometimes inserted between the second and third haemal spines in Luciogobius sp. 4 sensu Maeda et al. (2008)] ( Shibukawa et al., 2019; Koreeda & Motomura, 2021). Sexual dimorphism of the head is apparent in the L. platycephalus complex (see L. griseus n. sp.).

Shibukawa et al. (2019) listed differences in fresh or live coloration between the L. grandis and L. platycephalus complexes: dark green to dark gray in the former vs. bright yellow to orange in the latter. However, the fresh or live coloration of L. griseus n. sp. and Luciogobius sp. 7 are also dark green or dark yellow (see Shibukawa et al., 2019: figs. 20–21; this study). Juveniles and adults of L. platycephalus are usually bright yellow to green in life, although larger adults often have relatively darker coloration (this study). In addition, the population of L. platycephalus in northwestern Kagoshima Bay, Kyushu, Japan is relatively darker than those in other sites ( Koreeda et al., 2020). Possibly, the darker bodied specimen reported by Koreeda et al. (2020: fig. 3C, F) was an axanthic individual.