Shortbelly eel
The shortbelly eel is a unique species found exclusively in North and South America, belonging to the Synaphobranchidae family of cutthroat eels. Characterized by distinctive gill openings that merge into a single slit, this feature gives the eel the appearance of having a cut throat. Typically residing in cold, muddy bottoms at depths ranging from 98 to 885 feet (30 to 270 meters), the shortbelly eel thrives in coastal marine and brackish waters where rivers discharge sediment into the ocean. Growing up to about 20 inches (52 centimeters) long, it has a short, blunt snout and a thick brown body adorned with low dorsal fins and distinct black-tipped anal and caudal fins.
The eel primarily feeds on crustaceans and nearby fish, using its large mouth equipped with small teeth. While specific natural predators are not well-documented, little is known about its reproductive behaviors. Like many eels, shortbelly eels spawn annually, with the female releasing free-floating eggs that hatch into a larval form known as leptocephalus. This larval stage features unique telescopic eyes and may persist for a variable period before the eel undergoes metamorphosis into its adult form. The life span of the shortbelly eel remains largely unknown, highlighting the need for further research on this intriguing marine species.
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Shortbelly eel
The shortbelly eel is the only member of this family living in North and South America. The family name, cutthroat, comes from the design of the gill openings on the throat. The gill openings run into each other and become one slit, giving the appearance that the throat has been cut. The shortbelly eel lives along muddy bottoms at depths of at least 300 feet (90 meters) where rivers empty into the ocean.
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes
Family: Synaphobranchidae
Genus: Dysomma
Species: Anguillare
This eel belongs to the Synaphobranchidae family of cutthroat eels. This name comes from the pattern of their gill openings. The openings are set low on their bodies and merge into a single slit that runs along the midline of their throats. This single slit gives each eel the appearance that its throat has been cut. The gill openings of the shortbelly eel are just below the base of the pectoral fins.
The shortbelly eel lives in the costal marine and brackish waters of the Indo-Western Pacific and Atlantic Oceans. It usually inhabits cold, muddy bottoms of coastal waters at depths of 98 to 885 feet (30 to 270 meters). Brackish habitats occur where large rivers empty into the ocean, carrying large quantities of silt and sand from upstream erosion.
The full-grown shortbelly eel grows to around 20 inches (52 centimeters) long. Its snout is short, blunt, fleshy, and round and hangs over the lower jaw. Inside the mouth are a few large teeth. Its eyes are small but adequate for seeing in the murky depths. The eel's thick, scaly, brown body has a low dorsal fin which begins near the pectoral fins. The anal (rear) and caudal (tail) fins are black near the rear edges. The origin of the eel's name, shortbelly, is from the eel's feature of having a short belly, behind which the rest of the body tapers to the tail.
The diet of the shortbelly eel consists of crustaceans and fish living in or near the muddy bottom. It has a large mouth and small teeth. Natural predators are not known for certain.
The reproductive habits of shortbelly eels are little known. Like other eels, however, the male and female spawn once a year in the ocean. The female releases eggs into the water which the male then fertilizes. The eggs are likely to be free-floating and hatch within days or a couple of weeks. The adults do not give any further care to the eggs or the young once they hatch.
A newborn shortbelly eel does not look like its parents but looks instead like a small, slender, clear willow leaf. During this time it is called a leptocephalus.
The leptocephalus of the shortbelly eel has a feature that is unusual among eels. Only leptocephali in this family and two others, the Dysommatidae and Simenchelyidae, have telescopic eyes. Their eyes move in and out like the tube of a telescope.
The young eel remains in its larval, or non-adult, stage for an unspecified time before it metamorphoses, or changes, into the adult body form. For other eel species, this larval stage may last one to two years. As it metamorphoses, it becomes shorter, narrower, and more worm-like, as well as having pigments color its skin.
The life span of the shortbelly eel is unknown.
Bibliography
"Dysomma Anguillare Barnard, 1923." Fish Base, www.fishbase.se/summary/SpeciesSummary.php?ID=2659&AT=Arrowtooth+Eel. Accessed 1 May 2024.
"Species: Dysomma anguillare, Shortbelly Eel." Smithsonian Tropical Research Institute, biogeodb.stri.si.edu/caribbean/en/thefishes/species/4518. Accessed 1 May 2024.