image
Juan Miguel Artigas Azas,
Cichlid Room Companion
Editorial

Chalinochromis, the bridled Julidochromis

By , 2024. image
Last updated on 11-Mar-2024


Classification: Taxonomy and phylogeny, Lake Tanganyika.

" The Lake Tanganyika genus Chalinochromis has proven to be a junior synonym of Julidochromis, in this article I describe the steps and publications that lead to this conclusion "

Adult at Bilila Island An adult of Chalinochromis brichardi at Bilila Island (Kavala), Lake Tanganyika [Democratic Republic of Congo]. Photo by Ad Konings. (2014-05-08). determiner Patrick Tawil

The Lake Tanganyika cichlid genus Chalinochromis was described in 1974 by the Belgian ichthyologist Max Fernand Leon Poll (1908-1991), a member of the Royal Academies for Science and the Arts of Belgium, professor at Université Libre de Bruxelles, and curator at Musée Royal du Congo Belge in Tervuren. Chalinochromis is one of the 18 cichlid genera that he described during his lifetime. The initially monotypic genus (made up of one species) was proposed together with its type species Chalinochromis brichardi. When adult, C. brichardi is a uniformly beige colored — although some populations referred to as ‘ndobhoi’ have three longitudinal lines of black spots — elongated cichlid with a long dorsal fin base, a long anal fin, and a truncated tail. Its long shape allows it to swim in crevices of rocky reefs where it inhabits, and the pointed mouth to pick the invertebrates on which it feeds. The species was given the name of the Belgian explorer and Lake Tanganyikan cichlids exporter Pierre Brichard (1921-1990), who made substantial contributions to the knowledge of Lake Tanganyikan cichlids and provided the type material for C. brichardi.

Chalinochromis brichardi is quite similar to members of the genus Julidochromis which inhabit similar habitats in Lake Tanganyika, but four main morphological characteristics set it at first sight apart from species in this genus, calling the attention of Poll. The first and most obvious is the presence of three black interorbital lines (running from eye to eye) on the forehead, often described as “bridles”, while Julidochromis species have only one or two. The name Chalinochromis refers to this feature which translates from Greek as “bridled cichlid”. The second is having uniformly colored bodies in adult specimens (without marks in most populations), while Julidochromis are richly adorned with dark longitudinal bands and bars in some species. The third is a tail that is partly truncated, instead of rounded in Julidochromis. The fourth is that C. brichardi has a higher compressed body and a shorter head with a little hump on the nape, while Julidochromis have cylindrical bodies and pointed heads. There are still more minor differences, but these four are immediately obvious.

Adult at Nkondwe Island Adult of Chalinochromis sp. 'bifrenatus' at Nkondwe Island, Lake Tanganyika [Tanzania]. Members of the southern Tanzanian population usually shows a third longitudinal stripe at the base of the dorsal fin, though it is always thinner than in Chalinochromis popelini, not included in the fin and usually interrupted before its end. The caudal fin is also triangular rather than notched. Photo by Juan Miguel Artigas Azas. (2010-09-11). determiner Patrick Tawil

In the years after the description of the genus Chalinochromis, it was populated by two more species, and one more potentially undescribed. First, Patrick Tawil proposed in 1986 Chalinochromis sp. 'bifrenatus', a similar species to C. brichardi but with longitudinal stripes and two, instead of three, bridles. To our days this form has not been properly described, probably because its specific status has been doubted — some specialists consider it as a population of either C. brichardi, or more recently C. popelini. In 1989, Pierre Brichard described — just by mentioning it in an index — Chalinochromis popelini, visually a Julidochromis species with a slightly emarginated tail. Most recently in 2014, Chalinochromis cyanophleps was proposed by Kullander, Karlsson, Karlsson & Norén. This is a species that was long considered a dark morph of Chalinochromis sp. 'bifrenatus'. Patrick Tawil (2011) has been the first person to identify it as a potential new species, something the authors make no mention of. In fact, the species was provisionally labeled Chalinochromis sp. ‘patricki’ by Ad Konings in 2013, in reference to Patrick Tawil.

Adult at Fulwe Adult of Chalinochromis sp. 'bifrenatus' at Nkondwe Island, Lake Tanganyika, Tanzania. Photo by Ad Konings. (2003-11-13). determiner Ad Konings

Patrick Tawil (2011) makes the case that only a few of the differences given by Poll hold for all members of the genus Chalinochromis, while most are only present in the type species. He referred to Chalinochromis popelini, placed in Chalinochromis by its slightly emarginated caudal fin, as an otherwise perfect Julidochromis species. Tawil suggested as judicious to downgrade Chalinochromis to a subgenus of Julidochromis. Despite this, he makes no taxonomic declaration, and later in his 2020 book “Les lamprologues - Inventaire des genres et espèces” he maintains (with expressed doubts) the validity of Chalinochromis with four species.

Male in the aquarium A male of Chalinochromis popelini in the aquarium. at this age, Chalinochromis popelini is very similar to beige-colored Julidochromis ornatus except for its emarginate caudal fin. With age the body becomes proportionately longer compared to that of J. ornatus. Photo by Ad Konings. determiner Ad Konings

In September 2023, Ad Konings published a review of the Chalinochromis taxonomic situation in the journal of the American Cichlid Association. He describes each one of the supposed differences between these two genera species by species and why these differences are not convincing enough, at least to separate the two genera.

More importantly, Konings describes the results of three important phylogenetic works where different segments of the DNA of many Lake Tanganyikan cichlids are compared, in each one of those three phylogenetic works, including the monumental 2020 work by Fabrizia Ronco et al.. Two groups of Julidochromis species arise, one including the larger species (regani, marlieri, and marksmithi) and one including the smaller species (ornatus, transcriptus, and dickfeldi), which separated about two million years ago. All Chalinochromis species populate both groups, showing closer relationships with Julidochromis species than within themselves. Both genera arise as genetically inseparable.

The oldest lineage of both groups turns out to be the recently described Chalinochromis cyanophleps, which is part of the group of large Julidochromis, while the rest of the species of Chalinochromis form part of the group of smaller Julidochromis species. Because the type species of Julidochromis (J. ornatus) and Chalinochromis (C. brichardi) are both part of the same group of small species, it is not possible to use Julidochromis for one group and Chalinochromis for the other, and therefore Chalinochromis arises as a junior synonym of Julidochromis, as Konings proposes it.

For a deeper understanding of this subject, I highly recommend reading Tawil's (2011) and Konings' (2023) article and part from there to the rest of the publications.

References (9):

Citation:

Artigas Azas, Juan Miguel. (Mar 11, 2024). "Chalinochromis, the bridled Julidochromis". Cichlid Room Companion. Retrieved on Apr 17, 2024, from: https://cichlidae.com/section.php?id=341.