''Synodontis nebulosus'', known as the cloudy squeaker, or clouded squeaker, 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 lower

Zambezi River The Zambezi River (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than hal ...

basin of

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

and

Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...

. It was first described by German naturalist and explorer

Wilhelm Peters Wilhelm Karl Hartwich (or Hartwig) Peters (22 April 1815 in Koldenbüttel – 20 April 1883) was a German natural history, naturalist and explorer. He was assistant to the anatomist Johannes Peter Müller and later became curator of the Natural ...

in 1852, from a specimen collected in the Zambezi River at

Tete, Mozambique Tete is the capital city of Tete Province in Mozambique. It is located on the Zambezi River, and is the site of two of the four bridges crossing the river in Mozambique. A Swahili trade center before the Portuguese colonial era, Tete continues ...

. The

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''nebulosus'' is derived from the Latin word ''nebulosus'', meaning "foggy", "cloudy", or "full of mist".

Description

Like all members of the genus ''Synodontis'', ''S. nebulosus'' 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 help to identify the species. In ''S. nebulosus'', the humeral process is as broad as it is wide, with a pointed back end. The fish has three pairs of

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some ...

. 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 to a length a little shorter than the head. The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have short, simple branches, with secondary branches on the inner pair. The front edges of the dorsal fins and the pectoral fins of ''Syntontis'' species are hardened into stiff spines. In ''S. nebulosus'', the spine of the dorsal fin is slightly shorter than 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 about the same size as the dorsal spine, and serrated on both sides. The adipose fin is 5 times as long as it is deep. The anal fin contains four unbranched and eight-branched rays. The tail, or caudal fin, is deeply forked. 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. nebulosus'', the toothpad forms a short and broad 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. nebulosus'', there are about 18 teeth on the mandible. The base body color is yellowish green, with ill-defined, irregular brown to black spots. The underside of the fish is yellowish white. The fins are yellowish green with black spots. The maximum

standard 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 m ...

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 has been found in the middle Zambezi River basin, as well as the

Pungwe River Pungwe River ( pt, Rio Púngoè, links=no or ''Rio Púnguè'') is a long river in Zimbabwe and Mozambique. It rises below Mount Nyangani in the Eastern Highlands of Zimbabwe and then flows southeasteastward through the Manica and Sofala provinces ...

and Buzi River. It inhabits rivers and floodplains, favoring floodplains, but does not occur in rocky areas. 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. As a whole, species of ''Synodontis'' are omnivores, consuming insect larvae, algae, gastropods, bivalves, sponges, crustaceans, and the eggs of other fishes. The growth rate is rapid in the first year, then slows down as the fish age.

References

External links

{{Taxonbar, from=Q3644183 nebulosus Freshwater fish of Africa Fish of Malawi Fish of Mozambique Fish of Zambia Fish of Zimbabwe Fish described in 1852 Taxa named by Wilhelm Peters