M. bundoon, procne & reticulatus
There are two major clades which are recognizable by the lack of prominent stripes along the body, as well as frequently possessing a diagonal line extending from the eye to the dorsal fin. The first to be discussed is the bundoon Group, comprised of three taxa restricted in range to the Coral Sea and the Melanesian waters to the east.
M. bundoon in an aquarium. Note that the caudal lobes can get far more elongate than this. Credit: tamberav
It’s difficult to provide a simple, one-size-fits-all diagnosis for the bundoon Group, as the member taxa are more heterogeneous than in other clades. As far as appearances go, all three have a darkening running along the body, though this varies from dorsally in the Tongan endemic procne, to ventraly in the Coral Sea reticulatus, while the Fijian bundoon has evidence of both, as well as a midlateral stripe. It is perhaps most accurate to state that these three taxa show a tendency towards diffuse darkening along the body.
M. reticulatus, showing its eponymous markings along the body. Aquarium specimen collected near Cairns, Australia. Credit: Lemon Tea Yi Kai
There is, however, a particularly salient characteristic which can help define the group—these are the only three unstriped Meiacanthus which lack a Plagiotremus mimic. This is an unusual trait to use in recognizing evolutionary relationships, as the absence of a character can be unreliable as a character itself. Not only are we relying on this absence for a phylogenetically important trait, but we are relying on a completely unrelated group (Plagiotremus) to inform our decision here. Still, there is every reason to believe this is a legitimate phenomenon, wherein the phylogenetic correlation of a mimicry complex can elucidate relationships of the model organism. This will become particularly relevant when we consider another Coral Sea endemic, M. phaeus.
The rarely seen M. procne. Credit: John Randall
As aquarium exports, only bundoon appears with any regularity, and it is the only member of its group to have been captive-bred. M. reticulatus is collected from Cairns, Australia, though it seems to be a fairly uncommon offering. This is an intriguing species, which displays a subtle and unique reticulation along the sides of the body. Such a pattern is apparently found elsewhere only in the Red Sea endemic M.… More:
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