Johnius Bloch 1793
Creators: name: Hanafi, Norhafiz
name: Chen, Meng-Hsien
name: Seah, Ying Giat
name: Chang, Chih-Wei
name: Liu, Shang Yin Vanson
name: Chao, Ning Labbish
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Sciaenidae
Johnius

description: Key to the species of Johnius in the East Malaysia (Northern Borneo)
1a. Distinctly enlarged teeth on upper jaw and inner row of lower jaw teeth enlarged, conical J. (Johnieops) (Fig. 1 (A))...... 2
1b. Slightly enlarged teeth on upper jaw and inner row of lower jaw teeth uniform in size or molariform J. (Johnius) (Fig. 1 (B)). ................................................................................................... 3
2a. First pair of mental pores separated by symphysis, snout rounded; second anal-fin spine length 40–50% of head length................................................................................ J. plagiostoma (Bleeker, 1850)
2b. First pair of mental pores by a crescent-shaped groove, snout pointed; second anal-fin spine length 24–42% of head length............................................................................... J. borneensis (Bleeker, 1850)
3a. Chin with barbel............................................................ J. amblycephalus (Bleeker, 1855)
3b. Chin without barbel................................................................................... 4
4a. Dorsal-fin spines VIII or IX (usually IX); scale rows above lateral line from dorsal-fin origin 10–15, scale rows below lateral line from anal-fin origin 17–21................................................ J. trachycephalus (Bleeker, 1850)
4b. Dorsal-fin spines IX to XI (usually X); scale rows above lateral line from dorsal-fin origin 4–11, scale rows below lateral line from anal-fin origin 6–17............................................................................... 5
5a. Scales moderately small, scale rows above lateral line from dorsal-fin origin 7–11; scale rows below lateral line from anal-fin origin 11–17......................................................................................... 6
5b. Scales moderately large, scale rows above lateral line from dorsal-fin origin 4–8 (usually 5–6), scale rows below lateral line from anal-fin origin 6–14 (usually 6–10)................................................................... 9
6a. Body dark pigmented; lower fins black............................................... J. belangerii (Cuvier, 1830)
6b. Body silvery to light yellow; lower fins pale................................................................ 7
7a. Gill rakers slender, 9–12 on lower limb gill arch and moderately long ½–⅔ length of gill filaments at angle of arch........................................................................................ J. coitor (Hamilton, 1822)
7b. Gill rakers stiff, 7–9 on lower limb of gill arch and short ⅓–½ length of gill filaments at angle of arch.................. 8
8a. Body depth 25–30% of standard length; second anal-fin spine length short, stiff, 26–32% of head length.................................................................................................. J. latifrons Sasaki, 1992
8b. Body depth 20–25% of standard length; second anal-fin spine length long, stiff, 33–41% of head length............................................................................................... J. weberi (Hardenberg, 1936)
9a. Lower jaw with inner row of molariform teeth posteriorly............................. J. macrorhynus (Mohan, 1976)
9b. Lower jaw teeth all conical, uniform in size............................................................... 10
10a. Total outer gill rakers of 1 st arch 16–18................................................ J. carouna (Cuvier, 1830)
10b. Total outer gill rakers of 1 st arch 13–15................................................................... 11
11a. Gill rakers of outer gill rakers of 1 st arch at the upper limb, 4–5 (mode 4) and lower limb 9–11 (mode 10) respectively.................................................................................... J. heterolepis Bleeker, 1873
11b. Gill rakers of outer gill rakers of 1 st arch at the upper limb, 4–6 (mode 5) and lower limb 8–10 (mode 9) respectively..................................................................................... J. sasakii sp. nov. this study
description: Published as part of Hanafi, Norhafiz, Chen, Meng-Hsien, Seah, Ying Giat, Chang, Chih-Wei, Liu, Shang Yin Vanson & Chao, Ning Labbish, 2022, Johnius sasakii, a new species of croaker (Perciformes: Sciaenidae) with a key to Johnius from East Malaysia, Borneo, pp. 393-409 in Zootaxa 5116 (3) on pages 406-407, DOI: 10.11646/zootaxa.5116.3.5, http://zenodo.org/record/6372220