Taxonomy
The genus Telmatochromis was erected by Boulenger in 1898. It is differentiated from other genera of the tribe Lamprologini by the presence of tricuspid instead of conical teeth in the inner oral tooth rows.
Telmatochromis temporalis was described from 4 specimens from 2 localities in the extreme south of Lake Tanganyika, in Zambia.
Telmatochromis temporalis was designated as type species of the genus by Regan in 1920.
The genus Telmatochromis currently comprises 6 species. Within the genus, 2 groups are recognised that differ in body shape and colouration.
The first group comprises species with:
- an elongate body
- short head
- greyish-white colouration
- 2 to 3 broad black longitudinal bands
The first group includes:
- Telmatochromis vittatus Boulenger 1898
- Telmatochromis bifrenatus Myers 1936
- Telmatochromis brichardi Louisy 1989
The second group comprises relatively deep-bodied species with a beige-brown colouration:
- Telmatochromis temporalis Boulenger 1898 (synonyms: T. burgeoni Poll 1942 and T. lestradei Poll 1942)
- Telmatochromis dhonti Boulenger 1919 (synonyms: T. caninus Poll 1942 and Julidochromis macrolepis Borodin 1931)
- Telmatochromis brachygnathus Hanssens and Snoeks 2003
Telmatochromis temporalis is most similar to Telmatochromis brachygnathus from which it is differentiated by a larger mouth and larger jaw and is diagnosed by an upper jaw length of 29.8–40.5% of head length, and a lower jaw length of 31.8–41.6% of head length.
Telmatochromis temporalis is dimorphic in body size and inhabits 2 different habitats in multiple sections of the lake.
The normal form has a standard length (SL) up to 85mm and the minimum SL at sexual maturity is 60mm. It occurs lake-wide along the shallow rocky shores and breeds in rock crevices.
The dwarf form has an SL up to 44mm and the minimum SL at sexual maturity 38mm. It shows a patchy distribution and inhabits and breeds within shell beds formed by the accumulation of empty gastropod shells (Neothauma tanganyicense).
Hence, the 2 forms of Telmatochromis temporalis show marked ecotypic variation. Genetic data have shown that the dwarf, shell-dwelling morph of Telmatochromis temporalis might have evolved from the normal, rock-dwelling morph independently in several regions of the lake, and that pairs of morphs at a given locality may represent early stages in the process of ecological speciation.
Habitus
- not sexual dimorphic
- no geographical colour races
- large canines on each jaw
- body elongate, with the occipital crest becoming a slight hump; diagonal and/or horizontal stripes on the body
- pharyngeal teeth, conical or subconical
- relatively high number of anal spines
