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Aulonocara auditor (Trewavas, 1935)

By , 1996. printer
Published
Ad Konings, 2012

Classification: Species overview, Lake Malawi.

Aulonocara aquilonium A male Aulonocara aquilonium Konings 1995 patrolling its territory. Photo by Ad Konings.

In May 1989, Walter Dieckhoff and I visited the northern region of Lake Malawi, north of Chilumba for the first time. Our trip took us to the Songwe River which is the border between Malawi and Tanzania. It took us two days and several dives to conclude that there are no rocky reefs, coasts, or islets between the border and Ngara. The entire coast, here, consists of sandy and swampy beaches although small rocks may lie scattered on the beach and suggest that the area is rocky.

At Ngara, the most northerly rocky area in Malawian waters, an intermediate type of habitat supports a number of rock dwelling cichlids including Aulonocara stuartgranti, the race with the orange patch on the body. While diving there for the first time I noticed some elongated sand-colored cichlids which moved in small groups through the habitat. At first glance they seemed to be of the genus Aulonocara, a species of the sand dwelling group. They were rather shy and I could take only two photographs. At that time I did not see any individual with male coloration, which could be a further indication that it belonged to the sand dwelling group of Aulonocara. Of course I was eager to have some specimens for a closer examination and asked Saulos Mwale, our boat-leader and an extremely skilled fisherman, to catch a few. Saulos needs only two words to describe the desired fish and he will catch it for you, usually much better colored specimens than the ones you had seen. Unfortunately, he could not find individuals with breeding coloration which plainly meant they were not there. However, two specimens were preserved and they later turned out to be A. auditor.

At the next location where we dived, at Mdoka, I found the same species again, but again no breeding males. Further south, none of us saw A. auditor again.

Gary Kratochvil and I went back to the same places in December 1990, where I found A. auditor in breeding coloration. In contrast to the few individuals I had seen in May 1989, we now observed hundreds of them in large schools. Males in full breeding coloration, however, were rare. Most individuals of this species of Aulonocara were found below 15 meters of depth. The few territorial males were found at about 20 m, at the deepest part of the coast where rocks were still present.

The territorial behavior of the males resembles closely that of the so-called Chitande Type Aulonocara ; A. auditor might therefore belong to that group of the genus as well. Males in breeding coloration "defend" their territories with little effort. Other species and females are tolerated at all times within the boundaries of the territory. Competing males are "chased" by raising the dorsal fin and obstructing their way. Under natural circumstances, I have never observed fights, neither in A. auditor nor in Chitande Type Aulonocara. In the aquarium, however, fights may occur. Territorial males live rather far apart in the wild and remain very static.

The territory of a male A. auditor usually lies on the sand between some stones or rocks. They were found only at the edge of the rocky habitat. Females occur in large schools and forage over the sand. Within such schools males with faint breeding colors were observed. These males, sometimes showed intolerance towards each other and "chased" each other from the feeding site. No territories were defended within the schools although the school and its members remained rather static.

Other species of Aulonocara were found in the schools together with A. auditor. Besides two different sand dwelling species, A. rostratum and A. sp. "Jumbo Blue", foraging individuals of A. ethelwynnae (Northern or Chitande Aulonocara) were also seen.

Ngara and Mdoka are the only two locations where two different species of the Chitande Type Aulonocara group are sympatric. Notwithstanding the observation that A. auditor has a similar behavior and habitat preference, it is morphologically clearly different from A. ethelwynnae. The snout of A. auditor is considerably longer than that of all other known species of the Chitande Type Aulonocara. In all the other species the snout profile is rounded whereas it is straight in A. auditor. This might mean that A. auditor is able to poke its snout deeper in the substrate than A. ethelwynnae and thus feed from a different population of invertebrates. Personally I think that food is abundant in their environment and that those two species are not competing with each other for food. The structure of the teeth in the jaws looks similar in all Chitande Type Aulonocara ; A. auditor is no exception. The four to six rows of teeth stand in a relatively wide band anteriorly and become a single row on the sides of the jaw. The flat lower jaw, with its teeth, is somewhat reminiscent of that of several Lethrinops species. A. auditor may be more of a sand dwelling species than any other Chitande Type Aulonocara. Territorial males of the other species in this group are found throughout the year; they don't seem to have a particular breeding season. One exception might be A. sp. "Chitande Type Kande" breeding males of which were rare in June 1989. In December 1990, this species was abundantly present around Kande Island and many territorial males could be observed.

At Kande Island, A. sp. "Chitande Type Kande" shares the habitat with several other species of the genus. Two of them, A. kandeensis and A. steveni, are found in its immediate vicinity. It might thus be possible that A. auditor and A. sp. "Chitande Type Kande" breed mainly at a time when other species of Aulonocara decrease their breeding activities. These two species might be unsuccessful in obtaining a territory when the other species are still at the peak of their breeding season.

Aulonocara ethelwynnae

Aulonocara ethelwynnae
Aulonocara sp. 'Chitande type Kande'

Aulonocara sp. "Chitande type Kande"
Aulonocara stuartgranti

Aulonocara stuartgranti

References (1):

Citation

Konings, Ad. (September 10, 1996). "Aulonocara auditor (Trewavas, 1935)". Cichlid Room Companion. Retrieved on December 16, 2018, from: https://www.cichlidae.com/article.php?id=27.