Johnius

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Johnius
Bearded croaker (Johnius amblycephalus)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acanthuriformes
Family: Sciaenidae
Genus: Johnius
Bloch, 1793
Type species
Johnius carutta
Bloch, 1793
Synonyms[1]

Johnius is a genus of marine ray-finned fishes belonging to the family Sciaenidae, the drums and croakers. They are commonly known as croakers due to their ability to produce purring, croaking and knocking sounds. The sounds are produced mainly at night and are thought to be either involved in defense or for courtship.[2]

Taxonomy[edit]

The genus name was erected by Marcus Bloch in 1793 based on a specimen obtained from Tranquebar from Reverend Christoph Samuel John which was named as Johnius carutta. There are about 36 species in the genus, all within the Indo-West Pacific waters.[3] This genus has been placed in the subfamily Otolithinae by some workers,[4] but the 5th edition of Fishes of the World does not recognise subfamilies within the Sciaenidae which it places in the order Acanthuriformes.[5]

Two subgenera are recognised within the genus Johnius, the nominate subgenus has an inferior mouth with the teeth on the lower jaw being uniform in size, although there may be a small number of molar-like teeth towards the rear of the jaw. They also have the teeth on the rear of the upper jaw relatively closely set. The subgenus Johnieops has a terminal or subterminal mouth with an inner row of enlarged teeth on the lower jaw and the outer teeth on the upper jaw are relatively widely spaced.[6] The type species of Johnieops is Sciaena osseus Day, 1876.[1] However, the two subgenera may not represent monophyletic groupings.[6]

Etymology[edit]

Johnius honours the Danish missionary Christoph Samuel John who collected specimens at Tranquebar for Bloch, presumed to include the types of Johnius carutta and Pennahia aneus.[7]

Species[edit]

Johnius includes 36 species,[8] divided into two subgenera:[7]

Some authorities recognise Johnius sina as a valid species,[10] while others treat it as a synonym of J. dussumieri.[8]

Characteristics[edit]

Johnius croakers are relatively small Scaienids, typically less than 30 cm (12 in). They have a characteristic hammer-shaped swim bladder with between 12 and 20 pairs of dendritic appendages along its sides.[6] The first lateral appendage extends to the dorsal corner of the gill opening. They have large paired sagittal otoliths that are triangular. These fishes typically have a small mouth that is positioned sub-terminally to inferiorly. A few species have a short barbel on the chin but most species have no barbel on the chin.[3] The largest species as J. dorsalis and J. dussumieri which both have a maximum published total length of 40 cm (16 in).[8]

Distribution[edit]

Johnius croakers are found in the Indo-Pacific region from eastern Africa to Australia and New Guinea.[8]

References[edit]

  1. ^ a b Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Sciaenidae". Catalog of Fishes. California Academy of Sciences. Retrieved 12 May 2023.
  2. ^ Lin, Yuan C.; Mok, Hin K.; Huang, Bao Q. (2007). "Sound characteristics of big-snout croaker, Johnius macrorhynus (Sciaenidae)". The Journal of the Acoustical Society of America. 121 (1): 586–593. doi:10.1121/1.2384844. ISSN 0001-4966. PMID 17297812.
  3. ^ a b Chao, Ning Labbish; Chang, Chih-Wei; Chen, Meng-Hsien; Guo, Chang-Chang; Lin, Bai-An; Liou, You-Yu; Shen, Kang-Ning; Liu, Min (2019). "Johnius taiwanensis, a new species of Sciaenidae from the Taiwan Strait, with a key to Johnius species from Chinese waters". Zootaxa. 4651 (2): 259–270. doi:10.11646/zootaxa.4651.2.3. ISSN 1175-5334. S2CID 201210739.
  4. ^ Kunio Sasaki (1989). "Phylogeny of the family Sciaenidae, with notes on its Zoogeography (Teleostei, Peciformes)" (PDF). Memoirs of the Faculty of Fishes Hokkaido University. 36 (1–2): 1–137.
  5. ^ J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. pp. 497–502. ISBN 978-1-118-34233-6.
  6. ^ a b c Kunio Sasaki (2022). "Family Sciaenidae Croakers, Drums and Cobs". In Phillip C Heemstra; Elaine Heemstra; David A Ebert; Wouter Holleman; John E Randall (eds.). Coastal Fishes of the Western Indian Ocean Volume 3 (PDF). South African Institute for Aquatic Biodiversity. pp. 389–414. ISBN 978-1-990951-30-5.
  7. ^ a b Christopher Scharpf & Kenneth J. Lazara, eds. (12 January 2024). "Order ACANTHURIFORMES (part 5): Family SCIAENIDAE". The ETYFish Project Fish Name Etymology Database. v. 6.0. Christopher Scharpf and Kenneth J. Lazara. Retrieved 24 March 2024.
  8. ^ a b c d Froese, Rainer and Pauly, Daniel, eds. (2023). Species of Johnius in FishBase. February 2023 version.
  9. ^ Norhafiz Hanafi; Meng-Hsien Chen; Yin-Giat Seah; et al. (2022). "Johnius sasakii, a new species of croaker (Perciformes: Sciaenidae) with a key to Johnius from East Malaysia, Borneo". Zootaxa. 5116 (3): 393–409. doi:10.11646/ZOOTAXA.5116.3.5. PMID 35391328. S2CID 247591447.
  10. ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Johnius". Catalog of Fishes. California Academy of Sciences. Retrieved 16 May 2023.
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