Chalinochromis is a small and disputed cichlid

Cichlid

Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...

 genus

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...

 from the subfamily Pseudocrenilabrinae

Pseudocrenilabrinae

The Pseudocrenilabrinae is a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. Previous authors recognized additional African...

; it contains just two species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. These ray-finned fishes are endemic to Lake Tanganyika

Lake Tanganyika

Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...

 in Eastern Africa's Great Rift Valley

Great Rift Valley

The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...

. The scientific name refers to the bridle

Bridle

A bridle is a piece of equipment used to direct a horse. As defined in the Oxford English Dictionary, the "bridle" includes both the headstall that holds a bit that goes in the mouth of a horse, and the reins that are attached to the bit....

-like markings across the heads of members of this genus. They have specialized jaws enabling them to feed on sponges
.

This genus has a puzzling relationship with the extremely similar species placed in Julidochromis

Julidochromis

Julidochromis is a genus of cichlids in the subfamily Pseudocrenilabrinae. They are commonly called julies and are endemic to Lake Tanganyika in eastern Africa. This genus includes at least 5 species, each with a number of subspecies and local variants of uncertain taxonomic status...

. In their mtDNA NADH dehydrogenase

NADH dehydrogenase

NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane that catalyzes the transfer of electrons from NADH to coenzyme Q...

 subunit

Protein subunit

In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles with other protein molecules to form a protein complex: a multimeric or oligomeric protein. Many naturally occurring proteins and enzymes are multimeric...

 2 sequence

DNA sequence

The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...

, Chalinochromis are closer to J. dickfeldi

Julidochromis dickfeldi

Julidochromis dickfeldi is a species of fish in the Cichlidae family. It is endemic to Lake Tanganyika in Africa where it is found in the Democratic Republic of the Congo, Tanzania, and Zambia.-References:...

, J. ornatus and J. transcriptus – in particular the latter two – than to any other living fish, while J. marlieri

Julidochromis marlieri

Julidochromis marlieri is a species of fish in the Cichlidae family. It is endemic to Lake Tanganyika in Africa where it is found in Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. In the aquarium trade, it is commonly known as Marlier's Julie or Spotted Julie.-References:*...

and J. regani are closer to Telmatochromis

Telmatochromis

Telmatochromis is a small cichlid genus of the subfamily Pseudocrenilabrinae. These ray-finned fishes are endemic to Lake Tanganyika in East Africa.-Systematics:7 species are included here...

. Julidochromis thus might need to be split in two, with Chalinochromis included in one lineage. Alternatively, there has twice been successful intergeneric hybridization between particular lineages of Julidochromis males and Chalinochromis females (males generally do not pass on mtDNA to their offspring). Yet another possibility is that Julidochromis is monophyletic and includes Chalinochromis; in this scenario males of the common ancestor of J. marlieri and J. regani would have hybridized with females of the common ancestor of Telmatochromis.

Chalinochromis are popular aquarium

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 fishes, and require similar care to Julidochromis. Like most lamprologine

Lamprologini

Lamprologini is a tribe of African cichlid fishes. It contains seven genera and nearly 100 species. Over half of the species in this tribe are in the large genus Neolamprologus. Most genera in the tribe are endemic to Lake Tanganyika, but one species of Neolamprologus Lamprologini is a tribe of...

species, Chalinochromis are secretive during spawning, often choosing a small cave or crevice to spawn inside. In the aquarium the species often spawns under flat pieces of slate.