''Synodontis guttatus'' is a species of

upside-down catfish The name upside-down catfish is most commonly used by aquarists to refer to the mochokid catfish '' Synodontis nigriventris'' alternately known to ichthyologists as the blotched upside-down catfish or false upside-down catfish. However, a number ...

that is native to the

Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through ...

basin of Nigeria. It was first described by German ichthyologist

Albert Günther Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive re ...

in 1865, from the Niger River. The species name ''guttatus'' is the Latin word for "spotted", referring to the spots appearing on the fins and body of the fish.

Description

Like all members of the genus ''Synodontis'', ''S. guttatus'' has a strong, bony head capsule that extends back as far as the first spine of the dorsal fin. The head contains a distinct narrow, bony, external protrusion called a humeral process. The shape and size of the humeral process helps to identify the species. In ''S. guttatus'', the humeral process is rough, much longer than it is broad, and pointed at the end. The fish has three pairs of barbels. The maxillary barbels are on located on the upper jaw, and two pairs of mandibular barbels are on the lower jaw. The maxillary barbel is long and straight without any branches, without a membrane at the base. It extends about as long as the head. The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of ''Syntontis'' species are hardened into stiff spines. In ''S. guttatus'', the spine of the dorsal fin is about the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays. The spine of the pectoral fin is about as long as the dorsal spine and serrated on both sides. The adipose fin is 3 times as long as it is deep. The anal fin contains three unbranched and eight branched rays, and is pointed in the front. The tail, or caudal fin, is deeply notched. All members of ''Syndontis'' have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In ''S. guttatus'', the toothpad forms a broad crescent-shaped band. On the lower jaw, or mandible, the teeth of ''Syndontis'' are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in ''S. guttatus'', there are about 30 teeth on the mandible. The base body color is brown, and the body is covered with small, round dark spots. The maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of the species is . Generally, females in the genus ''Synodontis'' tend to be slightly larger than males of the same age.

Habitat and behavior

In the wild, the species is known from only one location in Nigeria in the lower Niger River. The species is harvested for human consumption. The primary threats to the species arise from pollution in its habitat and the small area of habitat, and it is listed as an endangered species. The reproductive habits of most of the species of ''Synodontis'' are not known, beyond some instances of obtaining egg counts from gravid females. Spawning likely occurs during the flooding season between July and October, and pairs swim in unison during spawning. The growth rate is rapid in the first year, then slows down as the fish age.

References

External links

{{Taxonbar, from=Q3765118 Endemic fauna of Nigeria guttatus Freshwater fish of West Africa Taxa named by Albert Günther Fish described in 1865