''Typhlobelus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

pencil catfish Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish (''Vandellia cirrhosa''), feared by some people for its alleged habit of entering into the urethra of hum ...

es native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Species

There are currently five recognized species in this genus: * '' Typhlobelus auriculatus''

de Pinna De Pinna was a high-end clothier for men and women founded in New York City in 1885, by Alfred De Pinna (1831–1915), a Sephardic Jew born in England. They also sold menswear-inspired clothing for women that was finely tailored. The flagship sto ...

& Zuanon, 2013de Pinna, M.C.C. & Zuanon, J. (2013): The Genus ''Typhlobelus'': Monophyly and Taxonomy, with Description of a New Species with a Unique Pseudotympanic Structure (Teleostei: Trichomycteridae). ''Copeia, 2013 (3): 441-453.'' * '' Typhlobelus guacamaya''

Schaefer Schaefer is an alternative spelling and cognate for the German word ''schäfer'', meaning 'shepherd', which itself descends from the Old High German '' scāphare''. Variants "Shaefer", "Schäfer" (a standardized spelling in many German-speaking ...

, Provenzano,

& Baskin, 2005 * '' Typhlobelus lundbergi''

, Provenzano,

& Baskin, 2005 * '' Typhlobelus macromycterus''

Costa Costa may refer to: Biology * Rib (Latin: ''costa''), in vertebrate anatomy * Costa (botany), the central strand of a plant leaf or thallus * Costa (coral), a stony rib, part of the skeleton of a coral * Costa (entomology), the leading edge of th ...

& Bockmann, 1994 * '' Typhlobelus ternetzi''

Myers Myers as a surname has several possible origins, e.g. Old French ("physician"), Old English ("mayor"), and Old Norse ("marsh"). People * Abram F. Myers (1889–after 1960), chair of the Federal Trade Commission and later general counsel and b ...

, 1944

Distribution

''T. guacamaya'' originates from the

Cuao River Cuao River is a river of Venezuela. It is part of the Orinoco River basin. See also *List of rivers of Venezuela This is a list of rivers in Venezuela. By drainage basin This list is arranged by drainage basin, with respective tributaries inden ...

in the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

River basin of

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. ''T. lundbergi'' inhabits the lower Orinoco River, between

Ciudad Bolivar Ciudad () is the Spanish word for "city". Ciudad or La Ciudad may also refer to: * La Ciudad (archaeological site), Hohokam ruins in Phoenix, Arizona * La Ciudad, district of Durango City Durango (, ) is the capital and largest city of the n ...

and Los Castillos de Guayana (near

Ciudad Guayana Ciudad Guayana () (English: Guayana City) is a city in Bolívar State (Venezuela), Bolívar State, Venezuela. It stretches 40 kilometers along the south bank of the Orinoco, Orinoco river, at the point where it is joined by its main tributary ...

), Venezuela. ''T. macromycterus'' is known from the

Tocantins River The Tocantins River ( , Parkatêjê dialect, Parkatêjê: ''Pyti'' ɨˈti is a river in Brazil, the central fluvial artery of the country. In the Tupi language, its name means "toucan's beak" (''Tukã'' for "toucan" and ''Ti'' for "beak"). It ...

near

Tucuruí Tucuruí is a municipality in the state of Pará in the Northern region of Brazil. The city is served by Tucuruí Airport. The name Tucuruí is a Tupi word that means "river of ants" or "river of locusts". It is the concatenation of two Tupi wo ...

Pará State Pará () is a state of Brazil, located in northern Brazil and traversed by the lower Amazon River. It borders the Brazilian states of Amapá, Maranhão, Tocantins, Mato Grosso, Amazonas and Roraima. To the northwest are the borders of Guyana an ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. ''T. ternetzi'' lives in the upper Rio Negro basin, Brazil.

Description

Species of ''Typhlobelus'' share the extreme reduction of pigmentation, loss of the

dorsal fin 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 ...

, the loss or extreme reduction of

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s, a reduced

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

, and the reduction or complete loss of eyes in some species. These fish are markedly miniaturized, yet retain a relatively well-ossified skeleton comparable in both bone differentiation and degree of calcification to that observed in larger trichomycterids. ''T. guacamaya'' is distinguished from all congeners by the presence of three

branchiostegal rays This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

(vs. four in ''T. ternetzi'' and ''T. lundbergi'', five in ''T. macromycterus''), posterior

naris A nostril (or naris , : nares ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates, ...

absent (vs. present, nares bilaterally paired), and the lack of

pleural rib The pleural cavity, or pleural space (or sometimes intrapleural space), is the potential space between the pleurae of the pleural sac that surrounds each lung. A small amount of serous pleural fluid is maintained in the pleural cavity to enable ...

s (vs. one pair of pleural ribs associated with the first free vertebra). ''T. lundbergi'' is distinguished from all congeners by the presence of four laterosensory pores on the head (vs. three). Both ''T. guacamaya'' and ''T. lundbergi'' are distinguished from '' ternetzi'' and ''T. macromycterus'' by the absence of eyes (vs. eyes present and

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

); between ''T. ternetzi'' and ''T. lundbergi'', the distinction may be between the presence or absence of eyes or eyespots. ''T. macromycterus'' has one or two

odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to t ...

s on the

opercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bon ...

and five branchiostegal rays, while ''T. ternetzi'' and ''T. lundbergi'' have no odontodes and four branchiostegal rays. These fish have greatly elongate, slender bodies. These fish have three pairs of

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whisker like sensory organ near the mouth (sometimes called whiskers or tendrils). Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the z ...

, all similar in length and general appearance. The mouth is ventral. ''Typhlobelus'' has a long duck-billed

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

that protrudes anteriorly well beyond the bases of the maxillary barbels.

References

{{Taxonbar, from=Q7861016 Trichomycteridae Catfish of South America Freshwater fish genera Catfish genera Taxa named by George S. Myers