They are grouped together because of common features in the structure of their gill arches. Indeed, many authors have considered them so distinct as to warrant separation in a monotypicsuperorder of the Teleostei, under the name Cyclosquamata. However, monotypic taxa are generally avoided by modern taxonomists if not necessary, and in this case a distinct superorder seems indeed unwarranted: together with the equally dubious superorder "Stenopterygii", the grinners appear to be so closely related to some Protacanthopterygii to be included in that superorder. In particular, this group might be the sister taxon of the Salmoniformes (salmon, trout, and relatives). As an alternative, the superorders are sometimes united as an unranked clade named Euteleostei, but in that case the Protacanthopterygii would need to be split further to account for the phylogenetic uncertainty. This would result in a highly cumbersome and taxonomically redundant group of two very small and no less than four monotypic superorders.[5][6]
An extinct clade of Aulopiformes, the suborder Enchodontoidei and its many constituent families, were dominant nektonic fish throughout much of the Late Cretaceous.[1][7] Several other extant aulopiform families also have Cretaceous representatives, and phylogenetic evidence indicates that the order as a whole diversified into its extant families around the Early Cretaceous, making it rather ancient. These diversifications included the earliest adaptations for deep-sea living, which is common among many extant aulopiform taxa.[8]
Many aulopiforms are deep-sea fishes, with some species recognized as being hermaphrodites, some with the ability to self-fertilise. Some are benthic, but most are pelagicnekton. In general, aulopiform fish have a mixture of advanced and primitive characteristics relative to other teleost fish.[5][9]
The larvae of some Aulopiformes are extremely bizarre-looking, with elongated fins, and do not resemble the adult animals. They were not only described as distinct species, but also even separated as genera and finally in a family "Macristiidae" which was allied with various Protacanthopterygii (sensu lato), but the initial assessment – which found "Macristium" to resemble the deepwater lizardfishes (Bathysauridae) in some details – was not far off the mark: "Macristium" species are larvae of Bathysaurus, while the supposed other "macristiids", "Macristiella" species are larvae of the deepsea tripodfishBathytyphlops.[10]
Wikimedia Commons has media related to Aulopiformes.
Diogo, Rui (2008). "On the cephalic and pectoral girdle muscles of the deep sea fish Alepocephalus rostratus, with comments on the functional morphology and phylogenetic relationships of the Alepocephaloidei (Teleostei)". Anim. Biol.58 (1): 23–29. doi:10.1163/157075608X303636.
Froese, Rainer, and Daniel Pauly, eds. (2006). "Aulopiformes"inFishBase. April 2006 version.
Woodhouse, S.C. (1910). "Flute". English-Greek Dictionary - A Vocabulary of the Attic Language. Broadway House, Ludgate Hill, E.C.: George Routledge & Sons Ltd. p. 330.
