Johnius borneensis (Bleeker, 1851)

(Common name: Sharptooth hammer croaker)

(Fig. 7, Table 6)

Otolithus borneensis Bleeker, 1851: 268 (type locality: Bandjarmasin, Borneo, Indonesia. Holotype (unique): RMNH 5980).

Johnius borneensis (Bleeker, 1851): Sasaki, 2000: 621; Sasaki, 2001: 3154; Ambak et al. 2010: 174; Lim et al. 2018: 138; Seah et al. 2021: 100.

Johnius carouna (non of Cuvier, 1830): Ng et al. 2015: 327.

Johnius glaucus (syn. of Day, 876): Mohamad Faisal, 2009: 98; Atan et al., 2010: 195.

Johnius goldmanni (syn. of Bleeker, 1851): DOF Malaysia, 2009.

Material examined. Non-types: NMMB-P37080 (4, 81.22 to 171.61 mm SL), Sandakan, Sabah, Malaysia, 26–27 February 2017 ; NMMB-P37081 (123.82 mm SL), Bintulu, Sarawak, Malaysia, 11 March 2017 ; NMMB-P37082 (88.44 mm SL), Bako, Sarawak, Malaysia, 17 March 2017 ; NMMB-P37083 (173.28 mm SL), Tawau, Sabah, Malaysia, 23 February 2017 ; NMMB-P37084 (2, 125.13 to 189.47 mm SL), Kuching, Sarawak, Malaysia, 17 March 2017 ; NMMB-P37085 (8, 112.48 to 146.3 mm SL), Miri, Sarawak, Malaysia, 7 March 2017 ; NMMBP37086 (7, 118.57 to 153.76 mm SL), NMMB-P26522 (130.4 mm SL), Kota Kinabalu, Sabah, Malaysia, 4 March 2017 ; NMMB-P31385 (151.69 mm SL), Muar, Johor, Malaysia, 19 March 2019 ; NMMB-P21543 (3, 108.06 to 170.76 mm SL), NMMB-P26492 (3, 120.62 to 153.71 mm SL), Pantai Remis, Perak, Malaysia, 14 June 2014 ; NMMB-P26514 (3, 141.99 to 181.76 mm SL), NMMB-P21545 (3, 131.06 to 180.39 mm SL), Kuala Kurau, Perak, Malaysia, 1–2 June 2014 ; NMMB-P23651 (11, 142.71 to 182.21 mm SL), NMMB-P23652 (3, 153.76 to 202.71 mm SL), Kuala Kedah, Kedah, Malaysia, 19 May 2014 ; NMMB-P21520 (2, 26.13 to 130.07 mm SL), NMMB-P21554 (2, 136.5 to 139.46 mm SL), Endau, Johor, Malaysia, 10–11 June 2014 ; NMMB-P21549 (2, 131.56 to 199.24 mm SL), Bagan Panchor, Perak, Malaysia, 5 June 2014 ; NMMB-P26515 (3, 129.82 to 148.61 mm SL), Tanjung Gemok, Pahang, Malaysia, 10 June 2014 .

Diagnosis. A species of Johnius with the following combination of characters: snout pointed, but not swollen or projecting; mouth large, oblique; teeth well differentiated into large and small in both jaws, but none canine-like; gill rakers slender, about 1/2 length of gill filaments at angle of arch, 9 to 15 on lower limb of first gill arch; second anal spine moderately long, 18 to 42% of head length; and scales moderately large, 5–6 scale rows above lateral line to origin of dorsal fin, 10 to 12 scale rows below lateral line to origin of anal fin (Hanafi et al., 2023).

Distribution. Indo-West Pacific, west to the Persian Gulf, east to southern China, Taiwan Province of China, and northern and northeastern Australia and New Guinea.

Remarks. Johnius borneensis is also a common species widely distributed in the East Malaysia waters, and Taiwanese waters (Hanafi et al. 2023). However, it was intensely collected at abundant sites at the Sarawak states, comparing with Sabah states due to ecological factor such as sandy and muddy habitat.