Today marks another first for Catalogue of Organisms - for the first time, the Taxon of the Week post is focusing on a single species. Specifically, the tropical fish Dendrochirus zebra (Cuvier, 1829)*, commonly known as dwarf lionfish, zebra turkeyfish, zebra butterfly-cod and doubtless a whole host of others of which I'm not even aware. And a very attractive animal it is too, as you can see in the photo above by K. Uchino. Dendrochirus zebra is a widespread species on reefs in the tropical Indian and Pacific Oceans. A map, as well as a whole heap of other information, can be found on FishBase.
*Things are a little confusing regarding the authority of this species - some sources (including FishBase) cite Cuvier (1829), while others such as Munro (1958) point to Quoy and Gaimard (1824). I have no idea which is correct.
The lionfishes or firefishes are two genera (Pterois and Dendrochirus) forming the subfamily Pteroinae of the family Scorpaenidae, the scorpionfishes (though Smith & Wheeler, 2006, found the pteroines to be more closely related to the Sebastidae rather than the Scorpaeninae). The differences between the two genera are fairly minimal, and a molecular phylogenetic analysis of seven (of thirteen) species of pteroines by Kochzius et al. (2003) failed to resolve their relative monophyly. Dendrochirus zebra was actually originally described as a species of Pterois (Munro, 1958), and it seems a return might be in order - proving once again that vertebrate workers tend to oversplit their genera. The name Dendrochirus ("tree-hand") refers to one of its supposed distinguishing characters, that some of the upper rays in the pectoral fin are branched. The other distinguishing character is that, unlike Pterois, Dendrochirus never has the upper pectoral rays free from the membrane.
The spectacular coloration of the pteroines makes them instantly recognisable, though the above photo of Dendrochirus zebra by Richard Ling shows quite well how the fish are not quite so obvious against a colorful reef background as one might expect. Like other scorpaenids, lionfish are slow-moving ambush predators. Their somewhat glum expression is the result of their relatively gigantic maws, which open up to inhale just about anything that can fit. Lionfish also resemble other scorpaenids in the presence of painfully venomous spines in the dorsal, ventral and anal fins. This toxicity has not prevented D. zebra from becoming popular in the marine aquarium industry. While D. zebra has spawned in captivity (FishBase), the majority of captive specimens would appear to be wild-caught. Unfortunately, FishBase suggests that this species is a relatively slow breeder and moderately vulnerable to overfishing.
One last thing which, though it relates not to Dendrochirus zebra but to another pteroine, is something I stumbled across while researching this post that is just too cool not to share. Take a look at the two photos below:
The above photos come from Fishelson (2006). The upper photo shows a typical individual of Pterois volitans, the red firefish. The lower photo shows a variant with the supraoral tentacles flattened into feather-like ornaments. Such a variant was first sighted near the southern end of the Sinai peninsula in the early 1980s. Since then, records of variant individuals have slowly spread southwards, and have since been recorded as far south as Kenya and the Comoros. While variant individuals remain extremely rare, they do seem to be slowly increasing in abundance...
Fishelson, L. 2006. Evolution in action-peacock-feather like supraocular tentacles of the lionfish, Pterois volitans – the distribution of a new signal. Environmental Biology of Fishes 75: 343-348.
Munro, I. S. R. 1958. The fishes of the New Guinea region: A check-list of the fishes of New Guinea incorporating records of species collected by the Fisheries Survey Vessel “Fairwind” during the years 1948 to 1950. Papua and New Guinea Agricultural Journal 10 (4): 97-369 (reprinted 1958. Territory of Papua and New Guinea Fisheries Bulletin no. 1).
Smith, W. L., & W. C. Wheeler. 2006. Polyphyly of the mail-cheeked fishes (Teleostei: Scorpaeniformes): evidence from mitochondrial and nuclear sequence data. Molecular Phylogenetics and Evolution 32 (2): 627-646.