Content uploaded by Ad Konings
Author content
All content in this area was uploaded by Ad Konings
Content may be subject to copyright.
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
26
LAKE
MALAWI
CICHLIDS
Ad Konings
A review of the sand-dwelling species of the genus
Aulonocara, with the description of three new species.
Summary
The genus Aulonocara can be divided into sev-
eral groups, each containing several species with
similar morphological and behavioural charac-
teristics. The sand-dwelling species forage and
breed in open habitats and the fact that they are
caught frequently in beach seine nets led to some
formal descriptions in the first half of this cen-
tury. All the sand-dwelling Aulonocara discussed
here inhabit the shallow waters (less than 50
metres depth) of Lake Malawi. Females and non-
territorial males have a light sandy-yellow to sil-
very coloration and are in general much lighter
than the rock-dwelling species. No gross mor-
phological distinction exists between these two
groups.
Introduction
The morphological features that characterise
Aulonocara are the pigmentation pattern consist-
ing of vertical bars (lacking horizontal or oblique
elements), the greatly expanded sensory canal
system of the skull (the pores of the preorbital
bone are wider than the spaces between them),
and a weakly developed chin.
Eccles, in Eccles & Trewavas (1989: 138), fur-
ther defines Aulonocara as having the infraorbital
bones so expanded that they exclude scales from
most, or all, of the cheek area. In the currently ac-
cepted concept of the genus, however, this ap-
plies only to the sand-dwelling species. The rock-
dwelling species also have enlarged sensory
pores in the skull, but in some cases the degree
of expansion allows for 2 to 4 rows of scales on
the cheek (eg in A. jacobfreibergi). Other
rock-dwelling species have just a single row of
scales on the cheek (eg A. stuartgranti) and share
this character with most sand-dwelling Aulono-
cara.
Aulonocara can be better characterised by their
foraging behaviour which has been described
earlier (Konings, 1989). This behaviour, termed
"sonar-feeding", is seen in all the Aulonocara spe-
cies that have been observed in their natural en-
vironment. It involves hovering motionless
about 5-10 mm above the sandy substrate and an
occasional dive with the snout into the sand.
While the fish is hovering its enhanced sensory
system registers any movement in the sand, and
the prey, once located, is captured during the
dive. This behaviour is so characteristic of Aulo-
nocara —at least of those species that have been
observed in the wild— that an individual fish
can be assigned to this genus solely by observing
its feeding technique.
The sand-dwelling species are characterised by
greatly enlarged pores in the bones of the skull.
The preorbital (or lachrymal), the preoperculum
and the lower jaw (see photo) are distended and
almost entirely occupied by the sensory canals.
The infraorbital bones in particular (see photo)
are greatly enlarged in order to accommodate the
sensory system. A similar situation is found in
the rock-dwelling members of the genus, but in
most species the enlargement of the infraorbitals
is less.
There is no clear distinction between the rock-
and sand-dwelling Aulonocara other than the ob-
servation that the sand-dwellers normally forage
and breed in open habitats. They do not seem to
be restricted to a specific area of (rocky) coast
and usually have a wide distribution.
26-36
27
© CICHLID PRESS The Cichlids Yearbook, volume 5 (1995):
In 1935 Trewavas described two large Aulono-
cara species which differed from each other in the
length of the pectoral fin, the size of the eye, and
the depth of the body. She named them A. rostra-
tum and A. macrochir. The latter was described
from a single specimen with a standard length of
149 mm. Later it was found that individuals
within a single breeding colony exhibited a
rather large variation in morphology (Konings,
1990), with characters overlapping those of the
two described species, and that similar variation
existed in two different colonies. Some species of
the closely related genus Lethrinops likewise ex-
hibit wide variation in morphology (Eccles &
Lewis, 1978) and this must be taken into consid-
eration when describing species of these genera.
Eccles (1989) discusses the relationships of
three other species which have been assigned to
Aulonocara but whose status within the genus is
unclear. One of these is A. auditor, whose holo-
type, a mature female with a standard length of
77.5 mm, was caught near Vua in the north of the
lake. A closer examination of the type has led me
to the conclusion that I have previously incor-
rectly identified an undescribed sand-dwelling
member of the ge-
nus as A. auditor
(Konings, 1990).
This new species
is here described
as A. aquilonium.
A. auditor does not
share the charac-
teristics of the
sand-dwelling
group, ie the
infraorbital bones
are not so en-
larged that the
cheeks are scaleless or have only a single row of
scales. A. auditor has three rows of scales on the
cheek and in addition exhibits a indistinct pat-
tern of three series of spots on the flank and at
the base of the dorsal. This pigmentation pattern
is reminiscent of Protomelas rather than Aulono-
cara. Not until more (live) specimens have been
examined can this species be assigned with cer-
tainty to Aulonocara; in the meantime it is
grouped with the rock-dwelling members of the
genus.
Methods
The measurements were made in accordance
with Barel et al. (1977). Their method gives a
more consistent result than the classic procedure
whereby length of snout and head are projec-
tions and the eye diameter is measured as the in-
side diameter of the ligamentous ring surround-
ing the eye. The small morphological differences
between many Malawi cichlids can be better as-
sessed when the point-to-point measurements of
Barel et al. are applied. However, most of the ra-
tios given by Trewavas (1935, 1984) and Eccles &
The upper two photographs
show the enlargement of the
pores in the preopercular, infra-
orbital, and preorbital bones.
Note the difference in the size
of the infraorbital bones in the
sand-dwelling
A. rostratum
(left) and in the rock-dwelling
A.
jacobfreibergi
(right).
Left: Ventral view of the lower
jaws (revealing the sensory
pores) of two sand-dwelling
cichlids: left
A. rostratum
and
right
Taeniolethrinops prae-
orbitalis
.
26-36
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
28
Trewavas (1989) cannot then be directly
compared with the ones given here. The depth of
the preorbital bone has been measured according
to the methods of Trewavas (1935), and is taken
as the length of a line from the centre of its orbital
edge, effectively bisecting the bone (Eccles & Tre-
wavas, 1989: 20, fig. 3).
Key to the sand-dwelling Aulonocara.
1. Eye diameter less than snout length ........... 2
Eye diameter greater than snout length ..... 4
2. Eye diameter fewer than 2.9 times in head
length ................................................................ 3
Eye diameter more than 2.8 times in head
length ................................................................ 4
3. Eye diameter 1.1 to 1.2 times in snout length
......................................................... A. guentheri
Eye diameter 1.3 to 1.4 times in snout length
.........................................................A. rostratum
4. Caudal peduncle length more than 2.2 times
in body depth ............................... A. gertrudae
Caudal peduncle length less than 2.1 times
in body depth .................................................. 5
5. 7 vertical bars below dorsal ......A. brevinidus
8 or more vertical bars below dorsal ........... 6
6. Interorbital width 1.6 to 1.8 times in caudal
peduncle depth and postorbital 2.6 to 2.7
times in head length ........................A. nyassae
Interorbital width 1.9 to 2.2 times in caudal
peduncle depth and postorbital 2.8 to 3.0
times in head length ................. A. aquilonium
Aulonocara nyassae Regan, 1922
Aulonocara nyassae (part) Regan, 1922: 726, pl. V, fig. 1;
Trewavas, 1935: 116; 1984: 117; Jackson, 1961: 590; Meyer et
al., 1987: 18; Eccles & Trewavas, 1989: 139; Konings, 1990a:
74; 1990b: 5.
Diagnosis
A small sand-dwelling Aulonocara attaining
about 100 mm standard length. It differs from A.
guentheri and A. rostratum in the larger eye,
shorter snout, and smaller preorbital; from A.
gertrudae in the longer caudal peduncle; from A.
brevinidus in having 8 to 9 bars below the dorsal;
from A. aquilonium in the longer postorbital part
of the head (see table on p. 36 for the respective
ratios).
Material examined
Koninklijk Museum voor Midden-Afrika (MRAC) 94-56-
P-24 to -30. Four males with standard lengths 98.0, 97.7,
93.2, and 93.3 mm and three females with standard lengths
87.2, 76.5, and 75.6 mm. Collected in Mazinzi Bay, Malawi,
on 3-12-1989 by the author.
Distribution
The holotype of A. nyassae is from an unknown
locality and was collected by Wood at the begin-
ning of the century. Eccles collected this species
south of Boadzulu Island. Mazinzi Bay, where
the specimens examined for this paper were col-
lected, is also situated in the southeastern arm of
the lake. I have previously recorded this species
from Mumbo Island as well (Konings, 1990a) but
these specimens subsequently turned out to be
another species lacking the much enlarged
infraorbital bones; moreover the thick lips and
stouter appearance suggest a generic placement
other than in Aulonocara. More research is re-
quired before this species can be properly classi-
fied.
Ecology
A. nyassae of the population in Mazinzi Bay
were observed in the sandy habitat where small
groups of 10 to 25 individuals were seen to for-
26-36
29
© CICHLID PRESS The Cichlids Yearbook, volume 5 (1995):
age from the substrate. A. nyassae was seen only
at depths of more than 20 metres. These small
groups usually contained one male individual
exhibiting territorial (breeding) coloration. When
the group was not feeding there seemed to be
some territorial action by that male but no
spawning site was constructed. This
may suggest that spawning takes place
at any random site, but since mouth-
brooding females were not observed it is
not clear whether or not the individuals
observed were sexually active.
The name A. nyassae has been incorrectly
applied to many different species, mainly
members of the rock-dwelling group of
the genus, by the aquarium trade. Eccles
(in Eccles & Trewavas, 1989) found that
the three specimens Regan used in 1922
for the description of A. nyassae in fact in-
cluded two different species. Since these
three were designated syntypes he had to
select one as the holotype for A. nyassae.
He chose the specimen from which the
drawing in Regan's description was made;
the other species he described as A. guen-
theri. Eccles recognised A. nyassae in a
population south of Boadzulu Island and
gave a detailed description of its live col-
oration, which agrees with that of the
fishes from Mazinzi Bay.
Aulonocara guentheri Eccles, 1989
Aulonocara nyassae (part) Regan, 1922: 726, pl.
V, fig. 1; Trewavas, 1935: 116;
1984: 117; Jackson, 1961: 590;
Meyer et al., 1987: 18.
Aulonocara guentheri Eccles,
in Eccles & Trewavas, 1989:
141; Konings, 1990a: 59.
Diagnosis
A small to medium-
sized sand-dwelling Aulonocara attaining about
120 mm standard length. It differs from A.
nyassae in the smaller eye, longer snout, and
deeper preorbital; from A. rostratum in the larger
eye and longer lower jaw; from A. gertrudae in
the longer snout and smaller eye; from A.
Left:
A. nyassae
at
Mazinzi Reef.
Top:
A. guentheri
; a male
from Kambiri Point.
Centre: A female
A.
guentheri
collected at
Thumbi East Island.
Bottom: A freshly caught
A. nyassae
at Mazinzi
Reef.
26-36
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
30
brevinidus in the smaller eye, the longer lower
jaw, and the deeper preorbital; from A.
aquilonium in the deeper body, the longer snout,
and wider interorbital (see table on page 36 for
the respective ratios).
Material examined
Koninklijk Museum voor Midden-Afrika (MRAC) 94-56-
P-31 to -36. Two males with standard lengths 101.9 and
113.8 mm and four females with standard lengths 86.5, 94.9,
96.8, and 108.4 mm. Collected at Thumbi East Island, Ma-
lawi, on 2-12-1989 by the author.
Distribution
A. guentheri is common in the southeastern arm
of the lake and is occasionally caught in beach
seines in Senga Bay. I have observed this species
in Monkey Bay, near Kadango, and near Makan-
jila Point.
Ecology
A. guentheri is a common cichlid of shallow
sandy habitats where it is normally seen forag-
ing in small groups of about 10 individuals.
Males and females, which both have yellow on
the lower part of the head, are found in the same
group, and such groups frequently mingle with
parties of other sand-dwelling species. Males
with territorial (breeding) coloration have not
been observed underwater, but some were found
in the beach seine nets of local fisher-
men in November and December.
This may suggest a restricted breed-
ing season, but more observations are
needed before a clear picture regard-
ing the breeding season can be ob-
tained.
Aulonocara rostratum Trewavas, 1935
Aulonocara rostrata Trewavas, 1935: 116;
Jackson, 1961: 590; Mayland, 1982: 138.
Aulonocara macrochir Trewavas, 1935: 116;
Jackson, 1961: 589; Eccles & Trewavas, 1989:
143.
Aulonocara rostratum; Meyer et al., 1987: 20;
Konings, 1989: 251; 1990a: 76.
Diagnosis
A medium-sized sand-dwelling
Aulonocara attaining about 160 mm
standard length. It differs from A.
nyassae, A. gertrudae, A. brevinidus, and A.
aquilonium in the smaller eye, longer snout, and
deeper preorbital; from A. guentheri in the
smaller eye and shorter lower jaw (see table on
page 36 for the respective ratios).
Material examined
MRAC 94-56-P-37 to -39. Two males with standard
lengths 94.1 and 100.0 mm and one female with standard
length 107.6 mm. Collected at Mdoka, Malawi, on 26-11-
1990 by the author.
MRAC 94-56-P-40. One female with standard length
129.5 mm. Collected in Mazinzi Bay, Malawi, on 3-12-1989
by the author.
MRAC 94-56-P-41 to -44. Two males with standard
lengths 140.9 and 151.4 mm and two females with standard
lengths 126.7 and 140.5 mm. Collected at West Reef, Ma-
lawi, on 6-12-1989 by the author.
Distribution
A. rostratum has a lake-wide distribution and
was observed in its natural habitat at Mdoka,
Msuli Point, Kande Island, and West Reef in
Malawi, and at Hongi Island in Tanzania.
Ecology
A. rostratum is regularly seen over open sandy
substrates at depths varying from 15 to 30
metres. True geographical races are not known
but males in the northern population appear to
Aulonocara rostratum
at Kande Island, Malawi.
26-36
31
© CICHLID PRESS The Cichlids Yearbook, volume 5 (1995):
Nkanda
Ikombe
Lupingu
Mdoka
Liuli
Charo
Likoma Is.
Lumbila
Kirondo
Makonde
Mazinzi Bay
Boadzulu Is.
Mumbo Is.
Thumbi East Is.
West Reef
N
s
i
n
j
e
R
.
Masinje
Cape Manulo
Msuli Point
Ruhuhu R.
Manda
Kande Is.
have a deeper blue colour.
Males in territorial (breeding) coloration group
into breeding colonies. Territorial males are
found throughout the year. Each male digs a
spawning crater in the sand and defends it
against all intruders. Such craters are sited about
two metres apart and lack the rim usually seen in
haplochromine nests in the lake. Females nor-
mally forage in separate groups or are solitary,
and apparently visit the otherwise exclusively
male breeding colonies only when ready to
spawn. Spawning has not been observed in the
wild.
Aulonocara gertrudae sp. nov.
Aulonocara sp. "jumbo blue"; Konings, 1990a: 69. This spe-
cies is sometimes known as the "Multispot Aulonocara" in
the aquarium hobby.
Etymology
Named in honour of my wife, Dr. Gertrud
Dudin, for her moral support, her interest in cich-
lids, and for her patience.
Diagnosis
A small to medium sized sand-dwelling Aulo-
nocara attaining about 110 mm standard length.
It differs from A. nyassae and A. brevinidus in the
shorter caudal peduncle; from A. guentheri and A.
rostratum in the larger eye and shorter snout; and
from A. aquilonium in the shorter caudal pedun-
cle and wider interorbital (see table on page 36
for the respective ratios).
Material examined
Holotype: MRAC 94-56-P-45. Male with standard
length 109.7 mm. Collected south of Nsinje River,
Masinje, Malawi, on 1-11-1989 by the author.
Paratypes: MRAC 94-56-P-46 to -49. One male with
standard length 99.0 mm and three females with stand-
ard lengths 85.2, 88.8, and 91.0 mm. Collecting data as for
holotype.
Other material: MRAC 94-56-P-50. One male with
standard length 97.8 mm. Collected at Cape Manulo, Ma-
lawi, on 1-12-1990 by the author.
MRAC 94-56-P-51 to -54. Two males with standard
lengths 88.2 and 88.7 mm and two females with standard
lengths 69.6 and 70.7 mm. Collected at Lupingu, Tanza-
nia, on 1-11-1993 by the author.
Description
Depth of body 2.4 to 2.9, and head length 2.6 to 2.9,
times in standard length. Snout 2.9 to 3.4, eye diameter 2.6
to 2.9, interorbital width 3.6 to 5.0, lower jaw 2.6 to 2.9, pre-
maxillary pedicel 3.2 to 3.7, and depth of preorbital 4.1 to
5.4, times in head length. Premaxillary pedicel 1.1 to 1.4
times in length of lower jaw.
26-36
MOZAMBIQUE TANZANIA
MOZAMBIQUE
MALAWI
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
32
Mouth positioned terminally.
Teeth in 4 to 5 rows in both upper
and lower jaws. Outer row contain-
ing unequally bicuspid teeth, inner
rows unicuspid; in some smaller
specimens the inner rows may con-
tain several tricuspid teeth. Lower
pharyngeal bone of a nonregistered
specimen with small bicuspid teeth
with the last few teeth of the inner
series somewhat enlarged but bi-
cuspid. 8 to 10 gill rakers on the
lower part of the anterior arch.
32 to 34 scales in a longitudinal
series; cheek with one row of scales.
Dorsal XVI-XVII 9-11. Anal III 8-
9. Length of last dorsal spine 2.1 to
2.4 times in head length. Pectoral
2.4 to 3.1 times in standard length,
0.9 to 1.1 in head length.
Caudal peduncle 6.2 to 7.0 times
in standard length, peduncle depth
1.1 to 1.4 in its length.
Distribution
A. gertrudae has a very wide distribution and is
found on the western as well as the eastern shores
of the lake. The most northerly population was
found at Ikombe, Tanzania, in the extreme north of
the lake. The most southerly population is that at
the type locality near Masinje, Malawi, on the east
coast. It has been observed at Mdoka, Msuli, and
Cape Manulo in Malawi .
Ecology
A. gertrudae seems to forage mainly in the
A. gertrudae
exhibits a small
degree of geographical
variation in the male breeding
coloration. Top: an aquarium
specimen from Ntekete,
Malawi. Bottom left: a male at
Lundu, Tanzania. Bottom,
right: A male at Lupingu,
Tanzania. Centre: a female at
Lupingu. Females exhibit the
same colour pattern in all
populations known.
26-36
33
© CICHLID PRESS The Cichlids Yearbook, volume 5 (1995):
somewhat muddy sediment on sandy bottoms
near river outlets. It is usually found at depths of
more than 15 metres, but north of the Ruhuhu
River in Tanzania it seems to exploit a different
habitat (Konings, 1994). At Ikombe, Nkanda,
Makonde, Lupingu, and Lundu (which is south
of the river) A. gertrudae was found in the inter-
mediate habitat at depths varying between 3 and
30 metres. The fact that the behaviour of these
populations differs from that of others may be
connected with the paucity of rock-dwelling
Aulonocara north of the Ruhuhu River. Even
though A. gertrudae is a non-sedentary sand-
dwelling cichlid the outflow of the Ruhuhu
River may form a barrier which keeps the north-
ern and southern populations separate. Males of
the northern populations have a bright orange
patch on the shoulder which is absent in the
southern populations, ie at Lundu and further
south. Because of this geographical variation A.
gertrudae may be the sand-dwelling species most
closely related to the rock-dwelling members of
the genus.
Territorial males dig crater nests in the sand or
defend a rocky cave (north of Ruhuhu) or may
dig a spawning pit against a rock. Spawning pits
can be 50 cm deep where the composition of the
substrate can accommodate such deep excava-
tions. Females, which can easily be recognised by
the yellow spots in the anal fin, forage in small
groups in the neighbourhood of the territorial
males. Males in nuptial colours were observed at
all times of the year.
The fact that A. gertrudae of the populations
north of the Ruhuhu River exhibit a different col-
oration and behaviour to that of the other known
populations may suggest that they represent an-
other species. However, general morphology
and the basic colour pattern of male as well as of
female —the distinct yellow spots in the anal fin
in combination with the yellow coloured ventral
fins of the female are useful characteristics for
distinguishing it in vivo from other Aulonocara—
permits the grouping of all populations into a
single species. The difference in spawning site
preference in northern males may well be influ-
enced by the lack of rock-dwelling Aulonocara
north of the Ruhuhu River.
Aulonocara brevinidus sp. nov.
Aulonocara sp. "blue gold sand"; Konings, 1990a: 54.
Etymology
From the Latin, brevis =
"short, shallow" + nidus =
"nest", referring to the shallow
spawning pit constructed by
the male.
Diagnosis
A small sand-dwelling Aulo-
nocara attaining about 95 mm
standard length. It differs
from A. nyassae in having 7
bars below the dorsal; from A.
guentheri and A. rostratum in
Left: Two males
A. brevinidus
in
territorial dispute (Masinje,
Malawi).
Below: A female
A. brevinidus
at
Chiloeolo, Mozambique.
26-36
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
34
the larger eye, shorter snout, and shorter preor-
bital; from A. gertrudae in the longer caudal pe-
duncle; and from A. aquilonium in the shorter
preorbital and in having 7 bars below the dorsal
(see table on page 36 for the respective ratios).
Material examined
Holotype: MRAC 94-56-P-55. Female with standard
length 89.9 mm. Collected south of the Nsinje River,
Masinje, Malawi, on 1-11-1989 by the author.
Paratypes: MRAC 94-56-P-56 to -61. Three males with
standard lengths 86.2, 86.4 and 91.3 mm and three females
with standard lengths 77.0, 81.5, and 86.3 mm. Collecting
data as for holotype.
Description
Depth of body 2.7 to 3.0, and head length 2.8 to 3.0, times
in standard length. Snout 2.9 to 3.4, eye diameter 2.5 to 2.7,
interorbital width 4.9 to 6.3, lower jaw 3.0 to 3.3, premaxil-
lary pedicel 3.5 to 3.9, and depth of preorbital 4.9 to 5.5,
times in head length. Premaxillary pedicel 1.2 times in
length of lower jaw.
Mouth positioned terminally. Teeth in 3 to 4 rows in up-
per jaw and 4 to 5 rows in lower. Outer row containing un-
equally bicuspid teeth, those of the inner rows unicuspid.
Lower pharyngeal bone of a nonregistered specimen with
small bicuspid teeth with the last few teeth of the inner se-
ries somewhat enlarged but bicuspid. 7 to 8 gill rakers on
the lower part of the anterior arch.
32 to 33 scales in a longitudinal series. One row of scales
on cheek.
Dorsal XVI-XVII 9-10. Anal III 8-9. Length of last dorsal
spine 2.0 to 2.6 times in head length. Pectoral 2.6 to 3.2 times
in standard length, 0.9 to 1.1 in head length.
Caudal peduncle 5.0 to 5.5 times in standard length, ped-
uncle depth 1.5 to 1.7 in its length.
Distribution
The most northerly localities where A. brevi-
nidus has been observed are at Lupingu and
Manda, Tanzania. The most southerly popula-
tion known is at Masinje, Malawi. In Mozam-
bique it has been found at Wikihi, Mara Point,
and at Chiloelo. Reports that this species also
occurs at Kande Island on the west coast of the
lake have not been confirmed. For the time
being, therefore, the distribution of A. brevi-
nidus must be considered to be restricted to the
east coast of the lake.
Ecology
Males of the northern and southern popula-
tions do not differ significantly in their territorial
(breeding) coloration. At all known localities A.
brevinidus was found at a depth of about 20 me-
tres. Males are territorial and defend a very shal-
low spawning pit no deeper than 2-3 cm with a
diameter of about 15-20 cm. Sometimes a male
defends a sandy patch between small stones.
Territorial males station themselves about two
metres from each other in the Masinje popula-
tion; in the other populations only a few males
were observed and these were more than five
metres apart.
The gut of a nonregistered specimen contained
26-36
Left: A male
A. brevinidus
at his shallow nest
(Wikihi, Mozambique).
Centre: A female
A. aquilonium
at Mdoka, Malawi.
Bottom: This specimen at Charo, Malawi, may be
conspecific with
A. aquilonium
.
Next page: A territorial male
A. aquilonium
(Mdoka,
Malawi).
35
© CICHLID PRESS The Cichlids Yearbook, volume 5 (1995):
sand grains, tiny snails, and rather large (1.5-
2 cm) shrimp-like crustaceans.
Aulonocara aquilonium sp. nov.
Aulonocara auditor; Konings, 1991: 33.
Etymology
From the Latin, aquilonium = "northern", refer-
ring to the species' northerly distribution in the
lake.
Diagnosis
A small sand-dwelling Aulonocara attaining
about 85 mm standard length. It differs from A.
nyassae in the larger postorbital; from A. guentheri
and A. rostratum in the larger eye, shorter snout,
and shorter preorbital; from A. gertrudae in the
longer caudal peduncle; and from A. brevinidus
in having 8 bars below the dorsal (see table on
page 36 for the respective ratios).
Material examined
Holotype: MRAC 94-56-P-62. Male with standard length
82.2 mm (total length 104.9 mm). Collected at Mdoka, Ma-
lawi, on 26-11-1990 by the author.
Paratypes: 94-56-P-63 to -71. Seven males with standard
lengths 68.7, 71.0, 76.6, 80.6, 81.2, 82.0, and 84.2 mm and two
females with standard lengths 71.3, and 72.6 mm.
Collecting data as for holotype.
Description
Depth of body 2.8 to 3.1, and head length 2.7 to 2.9, times
in standard length. Snout 2.9 to 3.3, eye diameter 2.6 to 2.9,
interorbital width 5.3 to 6.4, lower jaw 2.8 to 3.2, premaxil-
lary pedicel 3.5 to 4.3, and depth of preorbital 4.4 to 4.8
times in head length. Premaxillary pedicel 1.2 to 1.5 times
in length of lower jaw.
Mouth positioned terminally. Teeth in 4 to 5 rows in up-
per jaw and 5 to 7 rows in lower. Outer row containing un-
equally bicuspid teeth, teeth of the inner rows unicuspid.
Lower pharyngeal bone of a nonregistered specimen with
small bicuspid teeth with the last few teeth of the inner ser-
ies slightly enlarged. 7 to 9 gill rakers on the lower part of
the anterior arch.
32 to 33 scales in a longitudinal series. A single row of
scales on the cheek.
Dorsal XVI-XVII 9-11. Anal III 8-9. Length of last dorsal
spine 2.0 to 2.3 times in head length. Pectoral 2.7 to 3.1 times
in standard length, 1.0 to 1.1 in head length.
Caudal peduncle 5.1 to 6.1 times in standard length,
peduncle depth 1.3 to 1.6 times in its length.
Distribution
The type material was collected at Mdoka, Ma-
lawi; at Charo I photographed a male Aulonocara
that may be conspecific with A. aquilonium.
Ecology
In November and December A. aquilonium is
26-36
The Cichlids Yearbook, volume 5 (1995): © CICHLID PRESS
36
A. nyassae A. guentheri A. rostratum A. gertrudae A. brevinidus A. aquilonium
SL/body depth 2.6-2.9 (2.7) 2.5-2.7 (2.6) 2.5-2.9 (2.7) 2.4-2.9 (2.6) 2.7-3.0 (2.8) 2.8-3.1 (2.9)
SL/head length 2.8-3.0 (2.9) 2.6-2.7 (2.7) 2.7-2.8 (2.7) 2.6-2.9 (2.7) 2.8-3.0 (2.9) 2.7-2.9 (2.8)
SL/pectoral fin 2.4-2.9 (2.7) 2.5-2.9 (2.7) 2.6-3.1 (2.8) 2.4-3.1 (2.7) 2.6-3.2 (2.9) 2.7-3.1 (2.8)
SL/pelvic fin 2.7-4.3 (3.6) 3.4-4.3 (3.9) 3.4-4.6 (4.1) 3.0-4.0 (3.5) 2.8-4.3 (3.5) 3.1-4.2 (3.7)
SL/peduncle length 5.0-5.7 (5.4) 5.4-6.2 (5.8) 5.3-6.4 (5.9) 6.2-7.0 (6.5) 5.0-5.5 (5.4) 5.1-6.1 (5.6)
SL/peduncle depth 8.2-9.0 (8.6) 8.1-8.7 (8.3) 7.9-8.9 (8.4) 7.3-8.5 (7.9) 8.1-8.5 (8.3) 7.8-8.5 (8.1)
SL/snout 8.4-9.4 (9.0) 6.9-7.3 (7.0) 6.7-7.3 (7.0) 7.9-9.7 (8.3) 8.1-9.5 (9.0) 8.3-9.3 (8.7)
Depth/ped. length 1.8-2.1 (2.0) 2.0-2.4 (2.2) 1.9-2.3 (2.2) 2.2-2.9 (2.5) 1.8-2.0 (1.9) 1.7-2.1 (1.9)
Depth/snout 3.1-3.6 (3.3) 2.6-2.8 (2.7) 2.4-2.8 (2.6) 3.0-3.4 (3.3) 2.7-3.5 (3.2) 2.8-3.4 (3.0)
Depth/eye 2.8-3.2 (2.9) 3.0-3.3 (3.1) 3.0-3.8 (3.4) 2.5-3.3 (2.9) 2.5-2.7 (2.6) 2.4-3.0 (2.7)
Depth/preorbital 4.4-5.8 (4.8) 3.7-4.4 (4.0) 3.5-4.2 (3.7) 4.6-5.3 (5.0) 4.8-5.4 (5.2) 4.1-4.9 (4.5)
Depth/interorb. w. 5.1-5.7 (5.4) 4.3-5.2 (4.8) 4.8-5.5 (5.1) 4.1-5.1 (4.6) 5.2-6.1 (5.5) 5.3-5.8 (5.6)
Head/snout 2.9-3.2 (3.1) 2.6-2.8 (2.6) 2.5-2.7 (2.6) 2.9-3.4 (3.0) 2.9-3.4 (3.1) 2.9-3.3 (3.1)
Head/eye 2.7-2.9 (2.8) 3.0-3.2 (3.1) 3.2-3.5 (3.4) 2.6-2.9 (2.7) 2.5-2.7 (2.6) 2.6-2.9 (2.7)
Head/preorbital 4.3-5.1 (4.5) 3.7-4.1 (3.9) 3.4-4.1 (3.7) 4.1-5.4 (4.7) 4.9-5.5 (5.1) 4.4-4.8 (4.6)
Head/interorb. w. 4.8-5.6 (5.1) 4.4-5.2 (4.7) 4.5-5.5 (5.0) 3.6-5.0 (4.3) 4.9-6.3 (5.4) 5.3-6.4 (5.7)
Head/postorbital 2.6-2.7 (2.7) 2.9-3.0 (2.9) 2.8-2.9 (2.8) 2.7-3.0 (2.8) 2.7-2.9 (2.8) 2.8-3.0 (2.9)
Head/lower jaw 2.8-3.1 (3.0) 2.7-2.8 (2.7) 2.8-2.9 (2.9) 2.6-2.9 (2.8) 3.0-3.3 (3.1) 2.8-3.2 (3.0)
Head/prem. pedic. 3.5-4.0 (3.6) 3.3-3.7 (3.5) 3.3-4.2 (3.6) 3.2-3.7 (3.4) 3.5-3.9 (3.8) 3.5-4.3 (3.8)
Snout/eye 0.8-1.0 (0.9) 1.1-1.2 (1.2) 1.3-1.4 (1.3) 0.8-1.0 (0.9) 0.8-0.9 (0.8) 0.8-0.9 (0.9)
Snout/preorbital 1.4-1.6 (1.5) 1.4-1.6 (1.5) 1.3-1.5 (1.4) 1.4-1.7 (1.5) 1.5-1.8 (1.6) 1.4-1.6 (1.5)
Eye/preorbital 1.5-1.8 (1.6) 1.2-1.4 (1.3) 1.0-1.2 (1.1) 1.4-2.0 (1.7) 1.9-2.1 (2.0) 1.6-1.8 (1.7)
Eye/prem. pedic. 1.2-1.4 (1.3) 1.1-1.2 (1.1) 1.0-1.2 (1.1) 1.2-1.3 (1.2) 1.4-1.5 (1.4) 1.2-1.6 (1.4)
Lower j./prem. pedic. 1.1-1.3 (1.2) 1.2-1.4 (1.3) 1.1-1.5 (1.3) 1.1-1.4 (1.2) 1.2-1.2 (1.2) 1.2-1.5 (1.3)
Ped.length/ped.depth 1.4-1.8 (1.6) 1.4-1.5 (1.4) 1.3-1.6 (1.4) 1.1-1.4 (1.2) 1.5-1.7 (1.5) 1.3-1.6 (1.5)
Ped.length/interorb.w. 2.5-3.1 (2.7) 2.0-2.4 (2.2) 2.2-2.5 (2.3) 1.6-2.3 (1.8) 2.6-3.3 (2.9) 2.6-3.0 (2.9)
Ped. depth/interorb.w. 1.6-1.8 (1.7) 1.4-1.7 (1.5) 1.5-1.8 (1.6) 1.3-1.7 (1.5) 1.7-2.2 (1.9) 1.9-2.2 (2.0)
abundant at the rock-sand interfaces near Mdoka
and this is the period during which territorial
males were observed; in June foraging individu-
als were seen but in much smaller numbers.
Territorial males defend a small patch of sand
against conspecific males only, and were found
at a depth of approximately 20 metres. Foraging
females and non-territorial males congregate in
large schools and were found on the sand be-
tween and near rocks at depths varying from 12
to 25 metres. The single male photographed at
Charo occurred at a depth of about 40 metres. It
could not be caught for positive identification.
Acknowledgements
I would like to thank Mary Bailey and Dr.
George Turner for their helpful comments on an
earlier draft of the manuscript.
References
ECCLES, D.H. & D.S.C. LEWIS (1978) A taxonomic study of
the genus Lethrinops Regan (Pisces: Cichlidae) from Lake
Malawi. Ichth. Bull. Rhodes Univ. Part 2, No. 37; pp 1-12.
ECCLES, D.H. & E. TREWAVAS (1989) Malawian cichlid
fishes. The classification of some haplochromine genera. Lake
Fish Movies, Herten, Germany.
JACKSON, P.B.N. (1961) Checklist of the fishes of Nyasaland.
Occ. Pap. Mus. S. Rhodesia, 3; 25B.
KONINGS, A. (1989) Malawi cichlids in their natural habitat.
Verduijn Cichlids, Zevenhuizen, Netherlands.
KONINGS, A. (1990a) Book of cichlids and all the other fishes of
Lake Malawi. TFH Publications, Neptune, NJ, USA.
KONINGS, A. (1990b) De zandbewonende keizerbaarzen.
NVC periodiek (Dutch Cichl. Assn.) vol. 16 (4); pp 5-12.
KONINGS, A. (1991) Aulonocara auditor (Trewavas, 1935).
Cichlids Yearbook, vol. 1; pp 33-35.
KONINGS, A. (1994) The many faces of Aulonocara stuart-
granti. Cichlids Yearbook, vol. 4; pp 38-41.
MAYLAND, H.-J. (1982) Der Malawi-See und seine Fische.
Landbuch Verlag, Hannover, Germany.
MEYER, M.K., R. RIEHL & H. ZETSCHE (1987) A revision
of the cichlid fishes of the genus Aulonocara Regan, 1922
from Lake Malawi, with descriptions of six new species.
Cour. Forsch. Inst. Senckenberg, 94; pp 7-53.
TREWAVAS, E. (1935) A synopsis of the cichlid fishes of
Lake Nyasa. Ann. Mag. nat. Hist. (10), 16; pp 65-118.
TREWAVAS, E. (1984) Un nom et une description pour
l'Aulonocara "Sulphur Head", poisson cichlide du lac Ma-
lawi. Rev. fr. Aquariol., 11 (1); pp 7-10.
26-36
The table below gives some ratios which are useful for
distinguishing the six sand-dwelling species. The figure
between brackets gives the average. SL= standard
length, ped.= peduncle, interorb. w. = interorbital width,
prem. pedic.= premaxillary pedicel, lower j.= lower jaw.
