Trematocranus pachychilus: A new species of Cichlid Fish from Lake Malaŵi.

The Cichlids are an extremely successful group of freshwater Perciform Fish (Perches), found in North, Central and South America, as well as the Caribbean, the Middle East, South Asia and, most notably Africa, where the group reaches its highest diversity. Over 800 species have been described from Lake Malaŵi alone, which is more species of freshwater fish than have been described from the entire Northern Hemisphere and slightly over 1% of every vertebrate species ever described. The genus Trematocranus currently contains three species, all endemic to Lake Malaŵi. These are fairly large Fish, reaching about 250 mm in length, typically having a spotted pattern, with several rows of teeth on their pharyngeal plates.

In a paper published in the journal ZooKeys on 14 March 2018, Katrien Dierickx and Mark Hanssens of Ichthyology at the Royal Museum for Central Africa, Bosco Rusuwa of the Department of Biology at the University of Malawi, and Jos Snoeks, also of Ichthyology at the Royal Museum for Central Africa, and of the Laboratory of Biodiversity and evolutionary genomics at Leuven University, describe a new species of Trematocranus from Jafua Bay on the Mozambique shore of Lake Malaŵi.

The new species is named Trematocranus pachychilus, meaning 'thick-lip', in reference to the lips of this species, which are notably thicker than those of other members of the genus. The species is described from three specimens caught in 1998 and stored in alcohol at the Royal Museum for Central Africa. These range from 117.7 to 154.6 mm in length, and have lost their original colouration. They are deep bodied and laterally flattened, with teeth sharp and pointed at the front of the mouth and flat and rounded at the back; the rear teeth of the outer rows are bicusped, while the inner row are unicusped, though in larger specimens there are more bicusped teeth.

Trematocranus pachychilus, preserved specimen, adult male, 154.6 mm SL, Lake Malawi, Jafua Bay. Dierickx et al. (2018).

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Five new species of Mbuna from Lake Malaŵi.

Mbuna are rock dwelling Cichlids known only from Lake Malaŵi in East Africa. They are typically colourful Fish, and often sexually dichromic (the males and females are different colours), making them popular in the aquarium trade. Mbunas are social Fish, with each males defending a territory a group of females. They are mouth brooders, with the females incubating the eggs in their mouths, and the newly hatched fry returning to the mothers mouth for shelter when threatened.

In a paper published in the journal Zootaxa on 8 May 2013, Jay Stauffer  and Kristin Black of the School of Forest Resources at Pennsylvania State University, and Adrianus Konings of the Cichlid Press describe five new species of Mbuna from Lake Malaŵi, all placed within the genus Metriaclima.

The first new species is named Metriaclima pambazuko, 'pambazuko' being the Swahili word for sunrise, a reference to the orange or red dorsal fins of the males. Metriaclima pambazuko is a 61-75 mm  (adult length) Mbuna found around Lundo and Hingi Islands on the Tanzanian part of the lake and Londi Bay on the Mozambique shore. The males are blue with 5-7 black bars the dorsal fin is blue gray or black, shading to yellow, orange or red away from the body. Females are grey-blue or light brown with grey bars.

Metriaclima pambazuko, (top) 70 mm male from Hongi Island, (bottom) 55 mm female from Londo Bay. Stauffer et al. (2013).

The second new species is Metriaclima lundoense, 'lundoense' referring to Lundo Island, the only locality where the Fish was found. Metriaclima lundoense has an adult length of 63-85 mm. The males are blue with black bars, the females light brown with blue and green highlights and (sometimes) faint brown bars.

Metriaclima lundoense, (top) 80 mm male, (bottom) 70 mm female. Both from around Lundo Island. Stauffer et al. (2013).

The third new species described is named Metriaclima midomo, 'midomo' meaning 'lips' in Swahili, the Fish having enlarged lips relative to other members of the genus. Metriaclima midomo has an adult length of 66-99 mm. The males are blue with green highlights and 5-9 black bars, the females are blue with green highlights and 5-7 faint bars. The fish were found only around Lundo Island.

Metriaclima midomo, (top) 80 mm male, (bottom) 70 mm female. Both from around Lundo Island. Stauffer et al. (2013).

The fourth new species is named Metriaclima tarakiki, 'tarakiki' meaning slender in Swahili, the fish being elongate in shape. Metriaclima tarakiki has an adult bodylength of 72-120 mm, the males are blue-white with 7-9 black bars, the females have two colour schemes, some being light brown others being yellow or orange with black blotches. The fish were found around Ngkuyo Island and Higga Reef on the Tanzanian part of the lake.

Metriaclima tarakiki, (top) 110 mm male from Higga Reef, (bottom) 90 mm female from Higga Reef. Stauffer et al. (2013).

The final new species is named Metriaclima nigrodorsalis, 'nigrodorsalis' meaninf 'black-dorsal' in Latin, the males and some females having a black band on the dorsal fin. Metriaclima nigrodorsalis has an adult length of 55-84 mm. This is a variable Fish with several different colour schemes, the males can be light blue, dark blue or yellow, with a yellow or grey belly and 6-10 black bars, the females cna be blue or light brown with grey or dark brown bars. Metriaclima nigrodorsalis was found at N’kolongwe, Thundu, Nkhungu, Chiloelo, and Charlie’s Bay, all on the Mozambican part of the lake.

Metriaclima nigrodorsalis, (top) 75 mm male from N'kolongwe, (upper middle) 70 mm female from N'kolongwe, (lower middle) 75 mm male from Chiloelo, and (bottom) 80 mm male from Nkhungu Point. Stauffer et al. (2013).

Map of Lake Malaŵi, showing locations where Mbuna were sampled in this study. Stauffer et al. (2013).

See also Two new species of Cichlid Fish from Lake Victoria, A new species of Cichlid Fish from Lake Tanganyika and A new species of Cichlid Fish from Lake Malaŵi.

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A new species of Cichlid Fish from Lake Malaŵi.

The Cichlids are an extremely successful group of freshwater Perciform Fish (Perches), found in North, Central and South America, as well as the Caribbean, the Middle East, South Asia and, most notably Africa, where the group reaches its highest diversity. Over 700 species have been described from Lake Malaŵi alone, which is more species of freshwater fish than have been described from the entire Northern Hemisphere and slightly over 1% of every vertebrate species ever described. 

In a paper published in the journal Zootaxa on 6 August 2012, researcher and Cichlid specialist Michael Oliver describes a new species of Cichlid from Lake Malaŵi. The new species is based upon two specimens in museum collections; the first caught in an experimental sampling expedition, north of Thumbi Island West at a depth of 17-38 m, in 1980, and now sits in the collection of the Peabody Museum of Natural History at Yale University, and the second purchased from indigenous fishermen at Nkhata Bay in 1997, and now in the collection of the Royal Museum for Central Africa in Tervuren, Belgium. Since the Cichlid fauna of Lake Malaŵi has been studied and sampled extensively for many years and only two specimens of this fish are known it is presumed to be quite rare.

Map of Lake Malaŵi, showing the locations where the two specimens were found. Oliver (2012).

The new Cichlid is placed in the genus Hemitaeniochromis, which until now contained only a single species (Hemitaeniochromis urotaenia), and is given the name Hemitaeniochromis brachyrhynchus, the short-snouted Hemitaeniochromis. Hemitaeniochromis brachyrhynchus has a shorter snout than Hemitaeniochromis urotaenia, caused by a narrowing of the lacrimal bones (which form part of the eye socket); this also causes larger eyes in Hemitaeniochromis brachyrhynchus. The colouration of Hemitaeniochromis brachyrhynchus is unkown, as both preserved specimens have lost their original colour.

The Yale specimen (a) and Royal Museum specimen (b) of Hemitaeniochromis brachyrhynchus. (a) is 123.6 mm long and (b) is 81.5 mm long. Oliver (2012).

The closely related Hemitaeniochromis urotaenia. Oliver (2012).

See also Two new species of Sandperch from the South China Sea, A new species of Toothcarp from Iran, Two new species of Asian Sea Bass from South Asia, New species of Grenadier from Japan and Boney Fish on Sciency Thoughts YouTube.

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