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by Patrick Tawil |
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Here, we will deal with the third and last part of our trilogy dedicated to ‘wrasse-cichlids’ (the approximate translation of Julidochromis, a name built after Coris julis, the Mediterranean rainbow wrasse). This little group of Tanganyikan cichlids have very cryptic behavior, whose delicate colors are only equalled by their ferocious intraspecific relationships. My first article on these fishes was dedicated to the large species of the Julidochromis regani group (Tawil, 2009); then, we have presented another group of large species with thick papillose lips typical of the group, but classified in another genus, Chalinochromis (Tawil, 2011), and concluded that there was no discontinuity between them and authentic Julidochromis. The last group comprises species related to the delicate Julidochromis ornatus, archetype and first described species in the genus: this article is about them. In spite of Julidochromis ornatus being the type species of the genus, its species group can only, for the moment, be defined by default when compared to both of the other groups. Members of the regani group are distinguished by their large size (>12 cm or 4.7 in), their ample fins, their weakly-thickened lips as well as, usually, sex size reversal. Chalinochromis, for their part, exhibit certain features of which most remarkable are large size, the very papillose though short lips, the tendency of reduction of the genital papilla in males, and the truncated or notched caudal fin. By not adhering to these diagnostics, the ornatus group is a “default” group, which we could define by their rather small size (<12 cm or 4.7 in), their very prominent upper lip, and the tendency of their body to become dorso-ventrally rather than laterally flattened. | |
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As we saw previously (Tawil 2009, 2011), all three groups are not “tight”. On one hand Chalinochromis popelini is intermediate between the other Chalinochromis and J. ornatus, and on the other hand, Julidochromis sp. ‘regani Kipili’ is intermediate between J. regani and the same J. ornatus. By the way, since the previous installment dealing with Chalinochromis was published (Tawil 2009), in which I suggested that members of this group were perhaps closer to the true Julidochromis of the ornatus group than are those of the regani group, a biomolecular study (Sturmbauer et al., 2010) came to a similar conclusion, even suggesting the merger of the ornatus group into Chalinochromis. (In fact, in case of such a merger, Julidochromis would be the genus name since it has priority over Chalinochromis, and its type species would be ornatus). Such a radical end is, in my opinion, unnecessary, given the presence of intermediate forms and the strong resemblance between these three sub-groups. I think rather that we are dealing with a case in which the use of subgenera would be judicious. We don’t know the level of introgressions (that is to say: introduction of genetic material from other species by occasional hybridizations) led to the origin of species such as Chalinochromis popelini and C. sp. ‘bifrenatus’, whose characteristics are rather variable. Besides, J. sp. ‘regani Kipili’ seems rather stable and is easy to tell apart at quick glance, especially from the similarly yellow J. regani from Zambia, thanks to the melanic pattern and the morphology. Nevertheless, we could certainly expect natural hybrids, since introgression is the rule rather than the exception in lamprologines (Day et al., 2007). The tendency towards introgression seems stronger in this group than in the polygamous Rift Lakes species, where the presence of very typical color patterns in males constitutes a mechanism enhancing sexual segregation, i.e. the choice of the appropriate species-specific mate. While not reaching the level of “lined” Telmatochromis, where “parasitic” hybridization possibly constitutes a survival strategy (Tawil, 2010), the “Julies” group does not constitute an exception to the general tendency in the lineage, and all species tend to hybridize even in the natural habitat, and even between members of different sub-groups. An example is the Kasanga population in Tanzania, which includes Julidochomis with a reticulate rather than lined pattern; some individuals are of transcriptus type (small size, body flattened, thick lips), while others are of marlieri type (larger size, broad fins, narrow lips). | |
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Another phenomenon contributes to blur the limits between different lamprologine taxa to a surprising degree for such an ancient lineage and a priori less adaptable one, than, for example, that of the Lake Victoria haplochromines species flock. This phenomenon is the evolution of ecotypes, i.e. the emerging of sub-populations of individuals tightly adapted to a peculiar biotope inside the habitat of the species. The adaptive changes are a result of an important aspect of the ecotype, so much so that it tends to generate a distinct species. The most widespread kind of ecotype in Lake Tanganyika is the shell-dwelling one, which is encountered in nearly all lamprologine genera, especially in Telmatochromis. Curiously, Julidochromis does not produce regular shell-dwelling ecotypes; besides, given their very cryptic behavior and their need to remain unnoticed, it is becoming more and more obvious that these species are developing chromatic ecotypes. Indeed, it has been noticed that all around the lake, Julidochromis developed either a distinct lined coloration, including longitudinal stripes upon a yellow to beige background, or a checkered one, constituted by marbling or grid-pattern upon a cream white background (see Konings, 1998). In all likelihood, each of these colors is favored by the light conditions in the habitat. When the habitat is characterized by a rather uniformly colored background, for example near the sand zones, or among small-sized rocks that are more-or-less covered with sediment, Julidochromis tend to be lined, while in rocky habitats where the rocks are large enough to create contrasting half light zones, the grid-pattern is favored. The variation inside both pattern categories varies from one population to another, but these habitat constraints explain why some individuals inside a population may seem more similar to the closest “other” species than to their own nominal one. That’s why some J. regani from Kagongo in Burundi may be so similar to J. marlieri, and also, this is why some J. transcriptus exports from Pemba include a rather significant number of individuals which would easily be thought to be J. ornatus. We may also notice that the same chromatic variability is found in other lamprologines whose way of life and aspect are very similar to Julidochromis, for instance Neolamprologus buescheri. Indeed, the type population from Kachese is lined, while those from neighboring locations such as Chaitika or Katoto are checkered. We even also find similar variations in a member of another genus, Lepidiolamprologus kendalli, whose color is reminiscent of that of J. regani. | |
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From the northwestern Congolese coast, north of the Ubwari peninsula, comes the so-called “kissi” Julidochromis transcriptus, which became popular thanks to a very dark specimen whose photo is still found in the 1989 edition of Brichard’s last book. Many fanciers thought that this was a distinct race, but in fact, it is only a commercial name for the darkest and most beautiful specimens coming from the type locality, which is Pemba (= Bemba). In fact, in imports, some J. transcriptus from this locality may easily be confused with J. ornatus. Beside, some shipments of so-called “ornatus” were reputedly from Pemba, however they usually come from more farther north, from Uvira. Thus, we suppose that the area includes biotopes with large rocks housing typical transcriptus types as well as more intermediate ones with ornatus-like coloration. To these variations which are biotope-related, we may add the eco-phenotypic adaptability of the individuals themselves, which is easy to observe in aquaria. According to the tank in which they are kept, even the darkest transcriptus may appear pale in a tank with uniformly light surroundings (light stones, sand, and background without important shadows). | |
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Beside the Pemba individuals that correspond more or less to the “kissi” model, the Uvira Julidochromis, with their beautiful bright yellow crossed with sharp longitudinal stripes, have always been considered as belonging to the species J. ornatus. But, given the above observations, it seems more and more probable that in fact, they are closer to the typical transcriptus from Pemba, of which they are only an ecotype adapted to different light conditions. I would not be surprised if a thorough selection made on a rather reduced number of generations (a few dozens at most) would allow the switch from one chromatic form to another. In witness whereof, the yellow Julidochromis from Uvira should not be called J. ornatus, but J. transcriptus, from which it would be the “ornatoid” ecotype. Quite logically, in defining the genuine J. ornatus, we have to look at the type locality, in Zambia. The original description mentions Kinyamkolo (now Mpulungu Area) and Mbity Rocks. J. ornatus are frequently exported from this area. Many are not bright yellow, but beige, while others are quite as yellow as those from Uvira. Although their preserved state no longer allows us to imagine what their original coloration was, we may guess that the type specimens were rather yellow to deserve the “ornatus” name. Anyway, the southern ornatus type is also subject to color variation. | |
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Similarly as in the northern race, we also find in the south variations among the ornatus types, including grid-patterned populations, namely cream white with a more-or-less regular checkered pattern involving vertical and horizontal markings, thus of “transcriptus type”. The best known of these types are the so-called “Katoto” and “Gombe”, with many kinds of intermediate patterns. The most spectacular one is undoubtedly the “Gombe” one, since in the most typical specimen, the horizontal lines are broken into regularly spaced spots. As these spots are vertically linked by black “bridges”, the fish seem to bear vertical barring, which is unique among the whole Julidochromis group. It must be noted that this “perfect” pattern is not found on each individual and is probably geographically restricted, since we had shipments of fish reputedly coming from Kombe (Gombe) whose pattern was more similar to the Katoto specimens, which are more ordinary. | |
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With the same cause and effect, in the same way as in the north of the lake, or also between the regani and marlieri forms, it could be stated that the resemblance of these Katoto and Kombe types with the true J. transcriptus from Pemba is only superficial, and that they constitute an ecotype of J. ornatus. They seem to be larger than the J. transcriptus from the north, but this is not certain since some typical Kombe specimens are seemingly among the smallest members of the genus. Adding to the confusion, all these transcriptus types often (but not always) show an added bar on the cheek, and many Julidochromis of “transcriptus” coloration from Zambia or Tanzania have been considered as variants of J. marlieri (Konings, 1998) and are still mainly designated under this name. The reason comes from the fact that this cheek bar is usually typical of members of the regani group. But apart from this bar, which is more or less present in specimens inside a given population, and apart from the above-mentioned hybrids, the Katoto types perfectly fit with the ornatus types by their smaller size, hypertrophied lips, shorter fins, and dorso-ventrally depressed body. | |
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Between the geographical areas including the type localities of J. ornatus and J. transcriptus, which are located at both ends of the lake, we of course find intermediate populations. What I know from the Tanzanian populations is restricted to the photos taken in the natural habitat by Konings (except for specimens from Kasanga showing great variability) suggesting that both species may even hybridize. On the other side, the western coast, thanks to Heinz Büscher and to the fish that he brought back, we know that there are ornatus types in the Kapampa area in Congo, with an “ornatoid” ecotype at Korosha location, and a “transcriptoid” one at Kazia. Of course, here again, it is more than probable that these ecotypes are closer to each other than they are to other species of the “ornatus type”. | |
 
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To summarize, all these populations found all around the lake, which constitute what I called above the “ornatus types”, which are vicariant, morphologically very close, and without important chromatic differences correspond well to the definition of a super-species. But we also notice that it is conceivable to consider them as a single species including several sub-species (geographical forms). Given the weakness of the sexual segregation mechanisms among lamprologines, which was discussed above, and the numerous introgressions which ensue from that, it is obvious that it is particularly hard to give coherent definitions of the species inside this group, even considering the biological species concept as a standard. However, if we grade the species level by comparison with other lamprologines, the most coherent for the moment is still to consider the “ornatus types” as constituting a super-species including a few closely-related species, each of them including ecotypes which may be defined as subspecies. At a specific level, we probably will have to find new diagnostic definitions, but what is certain from now, it is that we cannot simply name all these forms under Julidochromis ornatus without any distinction; this makes no sense as its numerous forms are well recognizable. Whether they should be considered as species or subspecies still requires taxonomic work, but meanwhile, let us keep a conservative position as follows: —Julidochromis ornatus comes from the southern part of the lake, with an “ornatoid” ecotype coming from Mpulungu and nearby localities, and several “transcriptoid” ecotypes from Katoto, Kombe, and other locations (non-exhaustive list). —Julidochromis transcriptus comes from the northwestern coast, with “transcriptoid” ecotypes mainly from Pemba, while more northerly locations house an “ornatoid” ecotype. —Julidochromis sp. ‘ornatus Congo’ comes from the central Congolese coast (Kapampa area), with an “ornatoid” ecotype from Korosha and a “transcriptoid” one from Kazia. —The “ornatus types” from the eastern coast may constitute another race or species; data are insufficient, but according to the photographs (Konings, 1998) they seem to be mainly of “transcriptoid” ecotype. We still have to mention a species which does not belong neither to the Chalinochromis species group, nor to the large Julidochromis regani types and which is close to the ornatus super-species but not included in it: this is Julidochromis dickfeldi, which comes from the southern part of the lake from Kachese to Moliro (Konings, 1998). It is often mentioned here and there that J. dickfeldi should be considered as a Chalinochromis, perhaps because of its brownish coloration and its rather large size, but this is not justified. Indeed, as for the ornatus types, J. dickfeldi differs from Chalinochromis by its rounded caudal (vs truncated) as well as its very prominent upper lip. Moreover, its coloration is not particularly similar, since J. dickfeldi has a tawny dress flecked with black (vs. beige), and its fins are reticulated with blue, which makes impossible its confusion with Chalinochromis, even with the species closest to Julidochromis, namely C. popelini. Besides, when young, the latter may easily be confused with some beige colored populations of J. ornatus found in Zambia, not with J. dickfeldi. | |
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As expected, in the aquarium, all the members of the ornatus super-species show the same behavior, the only differences lying perhaps in some minor maximal size differences—this fluctuates between 6 and 9 cm (2.4–3.5 in) total length, sometimes slightly more in the Katoto types. There are no significant differences either with J. dickfeldi, whose maximum size lies at the higher end of this range. By comparison, species of the regani and Chalinochromis species groups reach maximal size of at least 12 cm (4.75 in) total length, sometimes exceeding 15 cm (6 in). The behavioral peculiarities of the smaller Julidochromis of the ornatus group are mainly related to this smaller size, which makes them more cryptic fish. The young keep hidden for a longer time, and the parents do not lose their habit of keeping the belly close to the substrate, sometimes by swimming upside down, while this habit tends to vanish in adulthood in larger members of the other groups. The intra- and interspecific aggressiveness is equivalent, i.e. very high, as these fish with a naturally low population density in the wild are very intolerant towards each other due to ecological competition between the individuals. For their maintenance, these fish fit well into a community tank 200 liter (50 gal) or more, in which they usually will easily breed and hide their progeny from hungry tankmates provided they have at their disposal enough shelters from which they are not dislodged by more powerful lamprologines. It is possible to keep mated pairs in dedicated tank 80 liter (20 gal) or even less, but with serious risks for the female in case the pair bond breaks. These fish are theoretically monogamous, but as it is observed in most lamprologines, given the important task partitioning between sexes—the female is in charge of the close care to the eggs and larvae, while the male is rather involved in territorial defense—polygamy often occurs, at least in the aquarium. For example, I have already observed a harem including one J. dickfeldi male and three females in a tank which was only 80 liter (20 gal) capacity. Finally, let’s note that in the ornatus super-species and in J. dickfeldi, one does not observe the size reversal which is usually found in larger members of the regani group. In all my own observations, the male was always the larger, but I do not exclude occasional exceptions, especially since I also observed it with Chalinochromis sp. ‘bifrenatus’ (while the opposite is the rule in this species group). Nor is the reversion mandatory in the regani group, even if it is the rule. Moreover, I have often observed that there is late sex determinism in these species, which varies according to the circumstances. For example, one could easily notice that with each Julidochromis pair, there is always a “satellite” young, which is tolerated close to the nest even when its siblings have been chased away by the parents. In the case of one parent dying or disappearing, it is automatically replaced by the “satellite”, which seems to make its sex fit with that of the remaining parent. I also had the opportunity to observe a J. marlieri pair, in which the female was the bigger fish. When it died, the remaining parent mated with the young satellite fish, but this one remained markedly smaller. Thus, either it was a small female, going against the usual sex reversal, or the male himself had changed his functional sex (such changes have been observed in some cichlids, especially from haplochromine lineage). Here, it would be easy for any aquarist to make experiments with several mated pairs, and then give statistical confirmation for one or another of these hypotheses. Then, the best way for determining which individual is the female is the parental behavior: the one which stays close to the eggs and hatched larvae in the nest is, in my experience, always the female, whether it is the smallest or not. Brichard, P. (1989) Pierre Brichard’s book of cichlids and all the other fishes of Lake Tanganyika. TFH Publications, 544 pp. Day, J.J., S. Santini & J. Garcia-Moreno, (2007) Phylogenetic relationships of the Lake Tanganyika cichlid tribe Lamprologini: The story from mitochondrial DNA. Molecular Phylogenetics and Evolution 45: 629–642. Konings, A. (1998) Tanganyika Cichlids in their natural habitat. Cichlid Press, El Paso, 272 pp. Sturmbauer, C., W. Salzburger, N. Duftner, R. Schelly & S. Koblmüller (2010)Evolutionary history of the Lake Tanganyika cichlid tribe Lamprologini (Teleostei: Perciformes) derived from mitochondrial and nuclear DNA data. Molecular Phylogenetics and Evolution 57: 266–284. Tawil, P. (2009) The graceful Julidochromis of the regani group: highly desired but at risk. Cichlid News 18 (3): 23–34. Tawil, P. (2010) The two faces of Telmatochromis. Cichlid News 19 (2): 14–23. Tawil, P. (2011) Chalinochromis, the bridled Julidochromis. Cichlid News 20 (1): 12–19. |
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