S. nematodes & yasha, alongside Amblyeleotris yanoi. Best friends forever! Credit: Takashi Nagamatsu
The shrimpgobies of the genus Stonogobiops are a common sight in any aquarium store, with species oftentimes selling for not much more than the cost of a cheap damselfish. Because of this, it might come as a surprise to learn that the half-dozen species that comprise the genus were completely unknown to science as recently as the late 1970’s! The Filamented Shrimpgoby (S. nematodes), a particularly ubiquitous and affordable species in our hobby, was originally known from just a single specimen. So how do we explain this apparent contradiction between the rarity and monetary value of these fish? Clearly, our knowledge of how to locate these fishes in the wild has improved drastically. Unlike some of their close relatives, Stonogobiops is primarily found at moderate depth (15-45m) and in sheltered sandy or rubbley habitats, generally some distance away from coral reefs. Many of the undescribed species which we’ll discuss in this review are known exclusively from deep, silty environments, where few divers venture. These fishes are in fact quite common in their preferred habitat—it just took a while to discover what that was. Identifying Stonogobiops is simple enough for aquarists; they are small (by shrimpgoby standards) and typically have four black diagonal bars along the side of the body. The only exception common to aquarists is the Yasha Goby (S. yasha), which has longitudinal red stripes. But the issue becomes murkier when discussing the obscure species S. larsonae, which has a seemingly divergent color pattern—a single reflective-blue longitudinal stripe and similar markings across the cheeks.
Credit: Larson & Murdy 2001
What this phenotypically heterogeneous mix of species shares in common is the possession of a toothed bone (the vomer) in the roof of the mouth. Amongst the enormous family Gobiidae, only a handful of disparate groups share this feature, none of which bear close relations to Stonogobiops. Based on genetic and morphological study, the closest relatives include the commonly seen Cryptocentrus, and the rarer Tomiyamichthys. This toothy mouth provides a strong character to define the genus, but the recent discovery of numerous undescribed species is forcing us to question that assumption, as these new forms illustrate a continuum of color patterns linking them to another poorly known genus of shrimpgobies—Myersina. To understand this properly, we’ll need to individually examine the coloration, ecology and biogeography of the many species in some detail.… More:
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