River predator — with last meal still inside — discovered in China. It’s a new species
The Pearl River criss-crosses southern China, meeting the Pacific Ocean just outside of Hong Kong.
Small tributaries flow from the surrounding regions of the Pearl River basin, returning water to the sea.
In Du’an, a finned predator calls the river system home.
While searching through a tributary spring, researchers caught brown sleeper fish, covered with black dots and splotches, according to a study published July 9 in the journal Zootaxa.
Just over 4 inches long, the fish has a “large and blunt” head and a longer snout than other known species, researchers said.
The fish’s eyes were “large” and “protruding outward,” according to the study, and “tiny teeth-like” projections appear on its upper jaw.
Its fins are transparent and covered with black spots, researchers said.
When its DNA was compared to sleeper fish already discovered in the region, it was unique.
The fish was identified as a new species and named Microdous hanlini, a fine-toothed sleeper, according to the study.
The fine-toothed sleeper was found in a “rapid-flowing spring” with a “rubble bottom” and a water depth between 8 and 16 inches, according to the study.
The fish are believed to be carnivorous, researchers said. When one of the specimens was dissected, the body of a smaller fish was found inside its stomach.
However, the fish inside belonged to the same new species, suggesting that it might not only be a predator but also cannibalistic.
Sleeper fish are part of the gobi suborder and are typically found in tropical and warm freshwater systems, according to Britannica. The group earns its name because sleepers are normally found lying on the bottom of rivers and streams.
