Grallenia is a genus of miniature gobies that you may not have heard of before. But with the recent addition of five new species to this group you will want to remember them in case you ever run into them at the LFS.
Grallenia is a curious name that honors Gerald R. Allen and is made up of species that are described as inconspicuous and nearly invisible to divers. They are somewhat translucent, living in sandy habitats, quick to hide, and none of them get bigger than one inch long, or 25mm.
This has made the Grallenia gobies virtually unknown and the five new species recently described represent more than half the eight total species in this genus. At least three of the new Grallenia gobies actually have some interesting color and pattern so these are the new ‘micro’ gobies we’ll be highlighting today.
So far all the species of Grallenia are known from the Western Pacific Ocean, reaching south into Central Indonesia and Eastern Australia. Grallenia compta from Milne Bay Papua New Guinea is mostly translucent with fine white spots and a general pattern that is made to disappear over white sandy bottoms.
One of the more interesting species of Grallenia is G. dimorpha which is also from PNG – while most of these micro gobies have some color differences between the sexes, G. dimorpha actually has different shaped dorsal fins. In male G. dimorpha the dorsal fin is a flat banner with red and yellow stripes, while in females the dorsal fin is a more typical triangular banner shape, with an elongated first dorsal spine and mostly clear in color.
There’s also Grallenia rubrilineata from the Philippines which, as the name implies, has a beautiful red band across both the first and second dorsal fins of males, but mostly clear in females. The two other recent inductees to Grallenia include G. baliensis from Bali and G. lauensis from Fiji and they are all described by Allen & Erdmann in the Journal of the Ocean Science Foundation.