Grammatotria lemairii Boulenger, 1899: The biggest sand-dweller of them all

The genus Grammatotria was established by Boulenger in 1899 as a monotypical genus, which it still is today, consisting of only one species G. lemairii. It has some similarities in common with Xenotilapia; the existence of a third lateral line, the coloring and the same requirements for habitats, and molecular phylogenies has also shown that Grammatotria and Xenotilapia indeed are closely related within the Ectodini tribe. In fact it is very likely that the genus Xenotilapia evolved directly from Grammatotria, as the most ancient split within the Ectodini tribe is observed between Grammatotria lemairii and the Xenotilapia-clade; Grammatotria lemairii therefore represent the most ancestral branch and species within the tribe (Sturmbauer & Meyer, 1993; Koblmüller et al. 2004).

Grammatotria lemairii is by far the biggest sand-sifting cichlid in Lake Tanganyika and the males can attain a maximum total-length of 25 cm, while the females stay shorter, rarely exceeding 18 cm. The body is very elongated, silvery-colored and the head is large with a very long snout; the eyes are oval and relatively big. There is no morphological distinction between the sexes when not breeding, besides the differences in size in adult individuals.

It is a very common species with a lake-wide distribution and it can easily be recognized by the black spot at the base of the caudal peduncle (Konings 1998). The type-specimen was caught in the south-western part of the lake at Moliro in D.R. Congo, located close to the border of Zambia (Boulenger 1899). No geographical variants are known.

The foraging grounds of this species are the vast sandfloors below 15 meters. It dines mainly on hard shelled crustaceans like small snails, clams and shrimps which it finds in the sand, but stomach investigations have also revealed invertebrates and algae (Poll 1956). Other sand dwelling species like Xenotilapia and Callochromis screens the upper layers of the sand, but Grammatotria lemairii goes deeper and searches for food a few centimeters below the surface of the sand. In order to reach this level they first blow the upper layer away, in a manner similar to Xenotilapia, quickly followed by a dart into the sand. The head may be completely buried while sand is collected (Konings 1998). Thus Grammatotria lemairii are capable of utilizing food sources that cannot be reached by other sand-dwelling species. The relatively big and fleshly lips can also be seen as an adaptation to the cope with hard-shelled prey.

The black spot on the base of the caudal peduncle help Grammatotria lemairii to stay together in the school, often numbered in several hundred or even thousand individuals, as the spot is easily distinguished against the light sandfloor. There are no hiding places on the sandfloor and if a danger turns up they will flee very quickly to deeper water for protection or alternatively make a quick dart into the sand completely hiding the body (Eysel 1990); a reaction to a danger, which also can be seen in two other sand-dwelling genera, Ectodus and Lestradea.

In the aquarium Grammatotria lemairii is a very peaceful, but big cichlid, and needs a rather large aquarium with a length of at least 150 cm (app. 5 feet). The bottom of the tank should consist of a relatively thick layer of fine sand and some scattered rocks could be added to provide the males with territories. G. lemairii should never be kept in pairs but in a small group, consisting of at least 5-6 individuals. They would be ideal tank mates with other sand-dwelling species in a large aquarium. As they are primarily a carnivorous species their diet should consist of different kinds of crustaceans, both frozen and fresh, like artemia, mysis, krill and shrimps.

Grammatotria lemairii is a maternal mouthbrooder and the relatively few aquarium observations available, indicate that male G. lemairii are not territorial and do not construct sand-scrape spawning nests. When not sexually active G. lemairii is silvery colored but when breeding sets in males acquire a black patch on the head and nape. The breeding male also has a bluish hue and some intensified black markings on the body. Displaying males sequester ripe females from the school and mate on the spot. Mouthbrooding females rejoin the school and incubate the eggs for app. four weeks before the fry are released. After the up to 50 fry has been released no further brood care has been noticed (Konings, 1998). In the aquarium the fry should be fed with newly hatched artemia, frozen cyclops and bosmins.

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Conclusion

Grammatotria lemairii is seen very seldom in the trade, even though it’s a very common species in Lake Tanganyika. I myself have seen them only once or twice in Germany. This absence in the hobby is properly caused by a combination of the size of the fish, thus demanding a relatively large aquarium, and their lack of color, compared to many other sand-dwelling species. That is a shame, as it is an interesting species in its own right, which could be a much appreciated element in the large sandfloor aquarium.