| Caranx sansun | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Perciformes |
| Suborder: | Percoidei |
| Superfamily: | Percoidea |
| Family: | Carangidae |
| Genus: | Caranx |
| Species: | C. sansun |
| Binomial name | |
| Caranx sansun (Forssk., 1775) |
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| Synonyms | |
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Caranx sansun is a dubious species of marine fish classified in the jack family Carangidae. Initially named as Scomber sansun, the validity of the species has been questioned by a number of authors, with the most recent review of Indo-Pacific carangids indicating it is probably a synonym of the blacktip trevally, Caranx heberi. However, this synonymy has not been accepted by all authorities, with Fishbase and ITIS both recognising it as a valid species. Due to the species name not being used by fisheries authorities or scientists, the species has no common name.
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As accepted by some taxonomic authorities, the species is classified within the genus Caranx, one of a number of groups known as the jacks or trevallies. Caranx itself is part of the larger jack and horse mackerel family Carangidae, a group of percoid fishes in the order Perciformes.[1]
The species was first described in a 1775 posthumous work by the Swedish naturalist Peter Forsskål under the name Scomber sansun, with the description based on a fish taken from the Red Sea off Yemen.[2] No holotype is known to exist; neither are any replacement types, making proper identification difficult if not impossible.[3] The species was initially referred to the broad mackerel genus Scomber as the genus Caranx was yet to be created.
Caranx sansun is accepted as a valid taxon by the two major taxonomic authorities this encyclopedia follows, ITIS and FishBase.[1][4] Despite this, the species has not been included in any review since 1968 when JLB Smith effectively labeled the species a nomen dubium, meaning correct identification cannot be made due to lack of material.[3] Early reviews of the carangids such as Cuvier's extensive 1833 volume Histoire Naturelle des Poissons treated the species as valid, although often noted similarity to other species, including those later be known as Caranx heberi, Caranx sexfasciatus and Caranx papuensis.[5] Like many species of carangid, the species remained in use based only on the description by Forsskal until 1968 when JLB Smith reviewed the taxon Scomber sansun. The research failed to find any type specimens and Smith attempted to resolve the taxon by splitting it into two species, which he named Caranx williamsi and Caranx celetus, and assigned holotype specimens.[3]
These species were both sunk by William Smith-Vaniz in major reviews of the Carangidae for the FAO Species Identification Program. C. williamsi is a junior synonym of Caranx heberi and C. celetus is synonymous with Caranx papuensis, with which the species was often wrongly confused.[6] The loss of the holotype specimen effectively renders the species a nomen dubium, with only the initial descriptions of the species available. The species was referred to as a possible synonym of Caranx heberi by Smith-Vaniz in the last major review of the Indo-Pacific carangids based on earlier descriptions.[6]
Caranx sansun has had a maximum size of 91.4 cm attributed to it.[4] The species is described as having a dorsal profile more strongly convex than the ventral, with the lower jaw slightly longer than the upper. The dorsal fin is in two parts, with the first fin containing 8 spines and the second consisting of 1 spine and 19 to 20 soft rays. The anal fin has two anteriorly detached spines followed by 1 spine attached to 16 or 17 soft rays.[7] The lateral line is curved anteriorly, with the curved and straight sections of approximately equal length and containing 30 to 32 scutes in the straight section.[7] Colour is said to be silver dorsally and golden yellow ventrally, with all fins yellow except the spinous dorsal fin, which is grey. There is no dark opercular spot. All the above parameters are consistent with those of Caranx heberi.[6] The range is given as the Red Sea and the seas of India, again consistent with C. heberi.[7]