Leptolebias
Encyclopedia
Leptolebias is a ray-finned fish genus
of the killifish
family
Rivulidae
. Like many of their relatives, they are rather ambiguously known as "pearlfish
".
They are endemic to the coastal areas of Brazil
, where they inhabit ephemeral pools in tropical forests like the Mata Atlântica
(or what remains thereof) and restinga
. Rare and little-known, the entire genus seems to be close to extinction. Specifically, Leptolebias species have been found in two regions to date: between Maricá
and Vila de Cava in Rio de Janeiro state, and between Itanhaém
in southern São Paulo state and the Paranaguá
bay catchment area
in Paraná state.
, as it does in many related genera. Otherwise, they are mainly colored in bright reddish and yellow hues, with iridescent or similarly conspicuous spots on the sides; their opercular
region bears red horizontal stripes that usually interconnect to form a web-like pattern.
The caudal fin of Leptolebias species is elongated and longer than deep, and the members of this genus have a single anterior supraorbital
neuromast. Like its close relatives in the subtribe Cynopoecilina, they have lost the large dermosphenotic contact organs on the males' pectoral fins and the second pharyngobranchial teeth, and lack horizontal red bars on the males' opercula; they retain however the plesiomorphic wide and triangular basihyal.
L. marmoratus – the Ginger Pearlfish – that the related genera Campellolebias
and Cynopoecilus are. These species have subsequently been separated in Notholebias.
The species remaining in Leptolebias are:
Whether Leptolebias leitaoi belongs in this genus, in Notholebias, or elsewhere is unresolvable. The type specimens are lost, and the species has not been found anymore in recent decades and may well be extinct already.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of the killifish
Killifish
A killifish is any of various oviparous cyprinodontiform fish . Altogether, there are some 1270 different species of killifish, the biggest family being Rivulidae, containing more than 320 species...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Rivulidae
Rivulidae
Rivulidae are a family of killifishes in the order Cyprinodontiformes. They are commonly known as rivulids, South American killifish or New World killifish. The latter names are slightly misleading however, as they are neither restricted to South America – though most are in fact found there...
. Like many of their relatives, they are rather ambiguously known as "pearlfish
Pearlfish
Pearlfish is a general name for a variety of marine fish species in the Carapidae family. Pearlfish have been found in tropical waters of the Atlantic, Indian, and Pacific Oceans at depths up to along oceanic shelves and slopes....
".
They are endemic to the coastal areas of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, where they inhabit ephemeral pools in tropical forests like the Mata Atlântica
Mata Atlântica
The Atlantic Forest is a region of tropical and subtropical moist forest, tropical dry forest, tropical savanna, semi deciduous forest and mangrove forests which extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the north to Rio Grande do Sul state in the south, and...
(or what remains thereof) and restinga
Restinga
Restinga is a municipality in the state of São Paulo in Brazil. The population in 2004 was 6,188 and the area is 246.37 km². The elevation is 910 m....
. Rare and little-known, the entire genus seems to be close to extinction. Specifically, Leptolebias species have been found in two regions to date: between Maricá
Marica
In Roman mythology, Marica was a nymph, the mother of Latinus. Latinus was fathered by Faunus, who was also occasionally referred to as the son of Marica. The sacred forest near Minturnae was dedicated to Marica. A lake nearby was also named after her....
and Vila de Cava in Rio de Janeiro state, and between Itanhaém
Itanhaém
Itanhaém is a municipality in the state of São Paulo in Brazil. The population in 2004 is 85,294, the density is 142.39/km² and the area is 599 km². The elevation is 0 m....
in southern São Paulo state and the Paranaguá
Paranaguá
Paranaguá is a city in the state of Paraná in Brazil. Founded in 1648, it is Paraná's oldest city.It is known for its excellent port facilities, being the sea port for Curitiba, the capital of Paraná....
bay catchment area
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
in Paraná state.
Description
These small fishes measure only 2-3 cm (around one inch) in standard length. The females are colored uniformly brown, without darker markings, as are the females of some related killifishes. The males may have some dark pigmentation, but it does not extend into the distal dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
, as it does in many related genera. Otherwise, they are mainly colored in bright reddish and yellow hues, with iridescent or similarly conspicuous spots on the sides; their opercular
Operculum (fish)
The operculum of a bony fish is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body....
region bears red horizontal stripes that usually interconnect to form a web-like pattern.
The caudal fin of Leptolebias species is elongated and longer than deep, and the members of this genus have a single anterior supraorbital
Supraorbital
Supraorbital refers to the region immediately above the eye sockets, where in humans the eyebrows are located. It denotes several anatomical features, such as:*Supraorbital artery*Supraorbital foramen*Supraorbital gland*Supraorbital nerve...
neuromast. Like its close relatives in the subtribe Cynopoecilina, they have lost the large dermosphenotic contact organs on the males' pectoral fins and the second pharyngobranchial teeth, and lack horizontal red bars on the males' opercula; they retain however the plesiomorphic wide and triangular basihyal.
Systematics
A cladistic study revealed that the genus Leptolebias in the old circumscription was paraphyletic: some species often placed here are actually less closely related to the type speciesType species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
L. marmoratus – the Ginger Pearlfish – that the related genera Campellolebias
Campellolebias
Campellolebias is a genus of fish in the Aplocheilidae family.It contains the following species:* Campellolebias brucei – Santa Catarina Sabrefin* Campellolebias chrysolineatus* Campellolebias dorsimaculatus...
and Cynopoecilus are. These species have subsequently been separated in Notholebias.
The species remaining in Leptolebias are:
- Leptolebias aureoguttatus (Cruz, 1974)
- Leptolebias citrinipinnis (Costa, Lacerda & Tanizaki, 1988)
- Leptolebias itanhaensis Costa, 2008
- Leptolebias marmoratusLeptolebias marmoratusThe ginger pearlfish is a species of fish in the Rivulidae family. It is endemic to Brazil.-Source:* World Conservation Monitoring Centre 1996. . Downloaded on 4 August 2007....
– Ginger Pearlfish - Leptolebias opalescensLeptolebias opalescensThe Opalescent Pearlfish is a species of fish in the Rivulidae family. It is endemic to Brazil.-Source:* World Conservation Monitoring Centre 1996. . Downloaded on 4 August 2007....
– Opalescent Pearlfish - Leptolebias splendensLeptolebias splendensThe Splendid Pearlfish is a species of fish in the Rivulidae family. It is endemic to Brazil.-Source:* World Conservation Monitoring Centre 1996. . Downloaded on 4 August 2007....
– Splendid Pearlfish
Whether Leptolebias leitaoi belongs in this genus, in Notholebias, or elsewhere is unresolvable. The type specimens are lost, and the species has not been found anymore in recent decades and may well be extinct already.