Luciogobius sp. 7

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 : 405-406

Luciogobius sp. 7 sensu Shibukawa et al. (2019)

[Standard Japanese name: Hauchiwa-yari-mimizuhaze]

Figure 10 ; Table 2

Luciogobius sp. 7 : Shibukawa et al, 2019: 67, figs. 19B, 20E–G, 21C (Shizuoka Pref., Japan).

Examined specimens. 10 specimens (33.9–65.9 mm SL) from Japan. Shizuoka Prefecture: KAUM –I. 139315, 43.1 mm SL, collected by R. Yamashita. KAUM –I. 157744–157747, 4 specimens, 33.9–65.9 mm SL, collected by H. Saito, 10 June 2021, KAUM –I. 165340, 49.3 mm SL, KAUM – I. 165341, 41.8 mm SL, collected by K. Mochizuki, 2 Jan. 2022, Yaizu. Kochi Prefecture: KAUM –I. 159028, 32.1 mm SL, KAUM – I. 159029, 33.2 mm SL, collected by H. Saito, 13 July 2021, Niyodo River mouth, Haruno. KAUM – I. 159033, 51.3 mm SL, collected by H. Saito, 22 July 2021, Shinjo River mouth, Suzaki .

Morphological characters of examined specimens. Total second dorsal-fin rays 10–12 (modally 12); total anal-fin rays 13–15 (usually 13 or 14); pectoral-fin rays 13–16; vertebrae 17 + 24–25 = 41 or 42; uppermost 2–4 rays free on pectoral fin; fewer than 5 pectoral-fin rays branched (central rays branched in specimens> 50 mm SL); AAA longer than half body depth at anus to anal-fin origin; dorsal-fin origin just above or behind anterior 1/3 of anal-fin base; pectoral-fin membrane strongly concave anteriorly; pelvic fins united.

Distribution. Currently known from Japan [Shizuoka, Wakayama and Kochi prefectures ( Shibukawa et al., 2019; Maeda & Hirashima, 2021; Okumura et al., 2023)]. The species prefers gravel deposits on beaches, rather than rocky coasts ( Shibukawa et al., 2019).

Remarks. The pre-dorsal fin length + P 2 A length of 98.4–102.1% of SL in Luciogobius sp. 7 sensu Shibukawa et al. (2019) is similar to that of L. platycephalus , but shorter than in L. griseus n. sp. ( Fig. 7 ).

Three individuals from Kochi Prefecture had relatively shorter pelvic-fin length (3.0–3.2 % of SL vs. 3.1–4.0% of SL) than in Shizuoka specimens ( Fig. 8F ), although specimens from both areas shared fewer than 8 branched pectoral-fin rays, a diagnostic character of the species according to Shibukawa et al. (2019). The latter reported also that branched rays were absent in individuals <38.0 mm SL.

Key to species of the Luciogobius platycephalus complex (except larvae and juveniles): each body proportion needs to be aware of changing with growth (see Figs. 7 , 8 )

1a. Pectoral fin with 7–13 branched rays (usually more than 10); posterior margin of pectoral-fin membrane not strongly concave (except for free rays).................................................................................. 2

1b. Pectoral fin with 0–8 branched rays (usually 6; 0 in specimens <38 mm in SL); posterior margin of pectoral-fin membrane strongly concave; occurs in accreting beach......................................................................................... Luciogobius sp. 7 sensu Shibukawa et al. (2019) (Japanese name: Hauchiwa-yari-mimizuhaze)

2a. Pre-dorsal-fin length <70% of SL (except in a specimen 26.1 mm SL); pelvic-fin length> 5.3% of pre-dorsal-fin length in specimens 32 mm SL or larger (> 5.9% in smaller specimens); pre-dorsal-fin length + P 2 A length 95.4–101.6% of SL; bright yellow to green body in live and fresh specimens (except individuals> 50 mm SL); usually occurs along temperate rocky coasts in Japan (Aomori Pref. to Tanega-shima island) and Korea ….............. Luciogobius platycephalus (Yari-mimizuhaze)

2b. Pre-dorsal-fin length> 69.5% of SL; pelvic-fin length <5.3% of pre-dorsal-fin length in specimens 32 mm SL or larger (<6.0% in smaller specimens); pre-dorsal-fin length + P 2 A length 103.0–107.3% of SL; gray in life (sometimes bluish or purplish), greenish dark brown when fresh; usually occurs near subtropical river mouths or coastal freshwater springs in Japan (Yaku-shima island to Okinawa-jima island)......................... Luciogobius griseus n. sp. (Sumizome-yari-mimizuhaze)

Figures

FIGURE 7. Relationship of (A) pelvic-fin length (P2F length) as % of pre-dorsal-fin length (PDF) and (B) PDF + P2A length as % of standard length (SL) in the Luciogobius platycephalus complex. Closed star: holotype of L. griseus; open stars: paratypes of L. griseus; circles: non-type specimens of L. platycephalus; triangles: Luciogobius sp. 7 sensu Shibukawa et al. (2019).

FIGURE 8. Relationships of (A) head length, (B) P2A length, (C) pre-dorsal-fin length (PDF), (D) pre-anal-fin length, (E) prepelvic-fin length, and (F) pelvic-fin length (P2F length) as % of standard length (SL) in the Luciogobius platycephalus complex. Closed star: holotype of L. griseus; open stars: paratypes of L. griseus; closed circle: holotype of L. platycephalus; open circles: non-type specimens of L. platycephalus; triangles: Luciogobius sp. 7 sensu Shibukawa et al. (2019).

FIGURE 10. Fresh specimens of Luciogobius sp. 7 sensu Shibukawa et al. (2019) from Kochi Prefecture, Shikoku, Japan. A: KAUM–I. 159033, male, 51.3 mm SL; B: KAUM–I. 159029, female, 33.2 mm SL; C: KAUM–I. 159028, female, 32.1 mm SL. Photographs taken immediately after fixation.