Goodeidae is a family of

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 ...

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 ...

endemic to

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

and some areas of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. Many species are known as splitfins. This family contains about 50

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), ...

within 18

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 ...

. The family is named after ichthyologist

George Brown Goode George Brown Goode (February 13, 1851 – September 6, 1896), was an American ichthyologist and museum administrator. Early life and family George Brown Goode was born February 13, 1851, in New Albany, Indiana, to Francis Collier Goode and Sarah ...

(1851–1896). The earliest fossil goodeid is '' Tapatia'', a goodeine from the middle

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

of Mexico. The earliest fossil empetrichthyine is '' Empetrichthys erdisi'' from the Miocene or

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Distribution

The family is divided into two subfamilies, the

Goodeinae Goodeinae is a subfamily of splitfins from Mexico, part of the Family (biology), family Goodeidae. They are small fish which mostly live in fresh water, especially around Mesa Central, west of Mexico City. Members of the subfamily are also found ...

and the Empetrichthyinae. The Goodeinae are endemic to shallow freshwater habitats in

, particularly along the

Mesa Central The Central Mexican Plateau, also known as the Mexican Altiplano (), is a large arid-to-semiarid plateau that occupies much of northern and central Mexico. Averaging above sea level, it extends from the United States border in the north to the T ...

area (especially the

Lerma River The Lerma River () is Mexico's second longest river. It is a river in west-central Mexico that begins in Mexican Plateau at an altitude over above sea level, and ends where it empties into Lake Chapala, Mexico's largest lake, near Guadalajara, ...

basin, smaller rivers directly south of it and inland to around the

Valley of Mexico The Valley of Mexico (; ), sometimes also called Basin of Mexico, is a highlands plateau in central Mexico. Surrounded by mountains and volcanoes, the Valley of Mexico was a centre for several pre-Columbian civilizations including Teotihuacan, ...

region), with some species found in

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

fringes at the Pacific coast, and north to central

Durango Durango, officially the Free and Sovereign State of Durango, is one of the 31 states which make up the Political divisions of Mexico, 32 Federal Entities of Mexico, situated in the northwest portion of the country. With a population of 1,832,650 ...

, central

Sinaloa Sinaloa (), officially the (), is one of the 31 states which, along with Mexico City, compose the Federal Entities of Mexico. It is divided into 18 municipalities, and its capital city is Culiacán Rosales. It is located in northwest Mexic ...

and north

San Luis Potosí San Luis Potosí, officially the Free and Sovereign State of San Luis Potosí, is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 59 municipalities and is named after its capital city, San Luis Potosí. It ...

. There are about 45 species of Goodeinae in 16 genera (some list 2 additional genera). The Empetrichthyinae are found in the southwestern

Great Basin The Great Basin () is the largest area of contiguous endorheic watersheds, those with no outlets to the ocean, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja Californi ...

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

, the

, and contains 4 species in 2 genera.

Physical information

The name "splitfin" comes from the fact that, in the male fish, the anterior rays of the anal fin are partly separated from rest of the fin. Splitfins can be up to in length, though most species are much smaller, around . Goodeid fish have

internal fertilisation Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For intern ...

, with males positioning themselves with a flexible part of the front anal fin, separated by a notch, which makes up the

andropodium 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 b ...

. Embryos hatch out of the egg within the ovarian follicle, and possess trophotaeniae, ribbon-like structures that emerge from the cloaca in front of the anal fin, on the ventral surface of the juvenile. These allow the absorption of nutrients within the ovary (

matrotrophy Matrotrophy is a form of maternal care during organism development, associated with live birth (viviparity), in which the embryo of an animal or flowering plant is supplied with additional nutrition from the mother (e.g. through a placenta). This ...

), and are shed by juveniles shortly after birth. Female goodeids do not store sperm, and so a

copulation Sexual intercourse (also coitus or copulation) is a sexual activity typically involving the insertion of the erect male penis inside the female vagina and followed by thrusting motions for sexual pleasure, reproduction, or both.Sexual inte ...

event must precede each pregnancy.

Conservation status

In recent years there has been a significant reduction in the range and size of Goodeid populations in this region, mainly due to

anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Anthropogenic may also refer to things that have been generated by humans, as follows: * Human impact on the enviro ...

disturbances, such as

pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

, habitat modification and

desiccation Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. The ...

; recent estimates put habitat loss at 80% compared to historic ranges. The low economic importance of Goodeid fish to Mexican

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

and industry has led to this family being largely ignored by conservation efforts, but their small size and the dedication of a small number of aquaria hobbyists has led to a recent increase in the amount of research dedicated to the family. These investigations have highlighted the implications for conservation efforts concerning other global freshwater

ichthyofauna A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish ...

. Several species are threatened or extinct according to the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

and the U.S. Fish and Wildlife Service * Vulnerable – bold characodon, darkedged splitfin, '' Goodea gracilis'', '' Allotoca dugesii'' * Endangered – bluetail splitfin, rainbow characodon, relict splitfin, '' Allotoca diazi'', Manse Spring killifish * Critically endangered – blackspot allotoca, Chapultepec splitfin, highland splitfin, Balsas splitfin, Tequila splitfin, butterfly splitfin * Extinct in the wild –

golden skiffia ''Skiffia francesae'', the golden skiffia or tiro dorado, is a species of splitfin Endemism, endemic to the Rio Teuchitlán, a tributary of Río Ameca in western Mexico. It is extinct in the wild, but has been maintained in Public aquarium, aquari ...

* Extinct – Ash Meadows killifish, Parras characodon, Raycraft poolfish, Pahrump Ranch poolfish

Life cycle and evolution

The majority of Goodeid fish are

viviparous In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

, typically giving birth to live young. The family includes a number of popular

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

fish, for example the

redtail splitfin The redtail splitfin or redtail goodeid (''Xenotoca eiseni'') is a species of goodeid fish from the family Goodeidae and subfamily Goodeinae. Like other members of Goodeinae, the redtail splitfin is native to Mexico and a livebearer. However, t ...

''Xenotoca eiseni''. Recent

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

studies have put the age of this family at approximately 16.5 million years, with the majority of divergence occurring in the

period. The speciosity of this family can be attributed to historical

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

and

geological Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth s ...

disturbance in this region, which created suitable conditions for

allopatric speciation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

of the fish.

Genera

The following genera are included in Goodeidae: Subfamily Empetrichthyinae – springfishes and poolfishes * '' Crenichthys'' – springfishes * ''

Empetrichthys ''Empetrichthys'' is a genus of splitfins endemism, endemic to the state of Nevada in the United States. In 1989 they only had an estimated population of 24800, while its two other subspecies had gone extinct. This species mating season typically ...

'' – poolfishes Subfamily

– typical goodeids and splitfins * '' Allodontichthys'' * '' Alloophorus'' – Bulldog goodeid * ''

Allotoca ''Allotoca'' is a genus of splitfins that are endemism, endemic to west-central and southwest Mexico, where restricted to the Lerma River, Lerna–Lake Chapala, Chapala–Grande de Santiago River, Grande de Santiago, Ameca River, Ameca and Balsas ...

'' – typical allotocas * '' Ameca'' – Butterfly splitfin, butterfly goodeid * '' Ataeniobius'' – Striped goodeid, bluetail goodea * '' Chapalichthys'' * '' Characodon'' – characodons * '' Girardinichthys'' * '' Goodea'' * '' Hubbsina'' * '' Ilyodon'' * '' Skiffia'' – skiffias * ''

Xenoophorus The relict splitfin (''Xenoophorus captivus'') is a species of splitfin endemic to the Pánuco River system in Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin Amer ...

'' – Relict splitfin * '' Xenotaenia'' – Leopard splitfin * '' Xenotoca'' * '' Zoogoneticus''

References

{{Authority control Viviparous fish Freshwater fish of Mexico Freshwater fish of the United States Percomorpha families Taxa named by David Starr Jordan Taxa named by Charles Henry Gilbert