The jellynose fishes or tadpole fishes are the small

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Ateleopodiformes. This group of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, containing a single family Ateleopodidae. It has about a dozen

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in four

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, but these enigmatic fishes are in need of

taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...

revision. The

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

means "''Ateleopus''-shaped", from ''

Ateleopus ''Ateleopus'' is a genus of ray-finned fish in the jellynose family Ateleopodidae. It is the type genus of its family, and the order Ateleopodiformes. For some time, it was known as ''Podateles'', because ''Ateleopus'' had been used to replace ...

'' (the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

) + the standard

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

order

suffix In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns and adjectives, and verb endings, which form the conjugation of verbs. Suffixes can ca ...

"-formes". It ultimately derives from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''atelēs'' (ἀτελής, "imperfect") + ''pous'' (πούς, "foot") +

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''forma'' ("external form"), the Greek part in reference to the reduced

pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectora ...

and

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hind ...

s of the jellynoses.

Description and ecology

Jellynoses are deep-water, bottom-dwelling, marine fishes. They are known from the

Caribbean Sea The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba ...

, eastern

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

, the western and central

Indopacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

, and the Pacific coast of

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

.Olney (1998), Nelson (2006): p.213 Primarily known from

mesopelagic The mesopelagic zone (Greek language, Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light ...

waters, an unidentified species of ''

'' was observed in the

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

and

Mariana Mariana is a given name (the link includes a list of people of this name). Mariana may also refer to: Literature * ''Mariana'' (Dickens novel), a 1940 novel by Monica Dickens * ''Mariana'' (poem), a poem by Alfred Tennyson, 1st Baron Tennyso ...

Trenches in the southwest Pacific at

hadal The hadal zone, also known as the hadopelagic zone, is the deepest region of the ocean, lying within oceanic trenches. The hadal zone ranges from around below sea level, and exists in long, narrow, topographic V-shaped depressions. The cumula ...

depths up to , extending the depth range of the family by . Jellynose skeletons are largely

cartilage Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...

(hence 'jellynose'), although they are true

teleosts Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts (), is, by far, the largest group of ray-finned fishes (class Actinopterygii), with 96% of all extant species of fish. The Teleostei, which i ...

and not closely related to

Chondrichthyes Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...

. The heads are large, with a bulbous nose, and the (usually) elongated body tapers towards the tail. Their

caudal fins Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by ...

are very small, and except for ''Guentherus'', it is merged with the long

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

(which has 70 fin rays or more). The

pelvic fins Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

of juveniles have up to 10 rays, but in adults this is reduced to a single elongated ray at the throat. Again, ''Guentherus'' is an exception, retaining several fins as adults and having

s that are located behind (not below) the pectoral fins.

dorsal fins A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found i ...

tend to be high, with a rather short base (9–13 rays, but in some as few as three); they are placed just behind the head. They have seven branchiostegal rays. The species have a range of sizes, the longest reaching . A

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...

is absent, and some species also lack scales. Most of the species are poorly known, but the highfin tadpole fish (''Guentherus altivelis'') is of potential interest for

commercial fishing Commercial fishing is the activity of catching fish and other seafood for Commerce, commercial Profit (economics), profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice ...

Systematics

Together with their relatives, the

Stomiiformes Stomiiformes is an order (biology), order of deep-sea ray-finned fishes of very diverse Morphology (biology), morphology. It includes, for example, Barbeled dragonfish, dragonfishes, lightfishes (Gonostomatidae and Phosichthyidae), loosejaws, ma ...

, the jellynoses are often placed in the

teleost Teleostei (; Ancient Greek, Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts (), is, by far, the largest group of ray-finned fishes (class Actinopterygii), with 96% of all neontology, extant species of f ...

superorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Stenopterygii Stenopterygii are a superorder of ray-finned fish in the infraclass Teleostei. Their validity is somewhat doubtful, as the group was established to separate, out of a large group of closely related Teleostei, a mere two rather peculiarly autapom ...

. Whether it is indeed justified to accept such a small group is doubtful; it may well be that the closest living relatives of the "Stenopterygii" are found among the superorder Protacanthopterygii, and that the former would need to be merged in the latter. In some classifications, the "Stenopterygii" are kept separate but included with the Protacanthopterygii and the

superorder Cyclosquamata in an unranked

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

called Euteleostei. That would probably require splitting two additional monotypic superorders out of the Protacanthopterygii, and is probably not ideal due to the profusion of very small

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

it would create. In fact, in some treatments, the jellynose fishes are even placed in yet another monotypic superorder, the Ateleopodomorpha. The Ateleopodidae have also been placed in the

Lampriformes Lampriformes is an order (biology), order of Actinopterygii, ray-finned fish. Members are collectively called lamprids (which is more properly used for the Opah, Lampridae) or lampriforms, and unite such open-ocean and partially Deep sea, deep-s ...

Myctophiformes The Myctophiformes are an order of ray-finned fishes consisting of two families of deep-sea marine fish, most notably the highly abundant lanternfishes (Myctophidae). The blackchins (Neoscopelidae) contain six species in three genera, whi ...

, which otherwise constitute additional superorders. The relationships of these to the taxa mentioned before is still not well resolved at all, and regardless whether one calls them Protacanthopterygii ''

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'' or Euteleostei, the

phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

of this group of moderately advanced Teleostei is in need of further study.Nelson (2006): pp.212-213, Diogo (2008)

References

* 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. * FishBase (2000)
Order Ateleopodiformes
Version of 2000-OCT-17. Retrieved 2009-SEP-28. * Glare, P.G.W. (ed.) (1968–1982): ''

Oxford Latin Dictionary The ''Oxford Latin Dictionary'' (or ''OLD'') is the standard English lexicon of Classical Latin, compiled from sources written before AD 200. Begun in 1933, it was published in fascicles between 1968 and 1982; a lightly revised second edition ...

'' (1st ed.). Oxford University Press, Oxford. * Olney, John E. (1998): Ateleopodiformes. ''In:'' : ''Encyclopedia of Fishes'': 158. Academic Press, San Diego. * Nelson, Joseph S. (2006): ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'' (4th ed.). John Wiley & Sons, Inc. * Woodhouse, S.C. (1910): ''English-Greek Dictionary - A Vocabulary of the Attic Language''. George Routledge & Sons Ltd., Broadway House, Ludgate Hill, E.C
Searchable JPEG fulltext

External links

* National Geographic News

September 22, 2009 (includes video of a possible new species of Jellynose) {{Authority control