''Hemibdella soleae'' is a marine

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...

in the family

Piscicolidae The Piscicolidae are a family of jawless leeches in the order Rhynchobdellida that are parasitic on fish. They occur in both freshwater and seawater, have cylindrical bodies, and typically have a large, bell-shaped, anterior sucker with which the ...

and the type taxon of its genus. Found in the northeastern Atlantic Ocean, it is a parasite of flatfish such as the

common sole The common sole, Dover sole, or black sole (''Solea solea'') is a species of flatfish in the family Soleidae. It is one of the largest fish in the ''Solea'' genus. It lives on the sandy or muddy seabed of the northern Atlantic and the Mediterr ...

Description

This small leech grows to a length of about when extended. It is roughly cylindrical, thicker in the middle and narrowing somewhat to a sucker at each end. Newly-hatched larvae are yellowish and transparent and have a pair of eyespots. As they grow they become opaque, with black speckles, and lose the eyespots; later they become beige or grey, and finally black.

Distribution and habitat

The range of ''Hemibdella soleae'' extends across the northeastern Atlantic Ocean, the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

and the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

. Like the

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

it parasitizes, it is

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

and

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

(living on and just above the seabed) and occurs at depths down to about .

Ecology

''H. soleae'' is an

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

of flatfish such as the

(''Solea solea''). Like other marine leeches, it feeds on its host's blood, but unlike most freshwater species, it does not drop off the fish after it has fed, instead remaining attached by its anterior sucker. In the juvenile leech, the remnants of each blood meal is visible through the transparent skin as a small red ball inside. In the northern part of its range, the common sole is the main host, but further south, other fish are also parasitized; these include the Senegalese sole (''Solea senegalensis''), the

wedge sole The wedge sole (''Dicologlossa cuneata''), is a flatfish of the family Soleidae. It is a bottom dwelling predatory fish inhabiting both sandy and muddy soils at depths between in the East Atlantic and Mediterranean Sea. It achieves a maximum siz ...

(''Dicologlossa cuneata''), the

bastard sole ''Microchirus azevia'', commonly known as the bastard sole, is a species of flatfish in the family Soleidae. It is found on the continental slope of the eastern Atlantic Ocean and the Mediterranean Sea at depths down to about . Description The ...

(''

Microchirus ''Microchirus'' is a genus of soles native to the Eastern Atlantic Ocean and Mediterranean Sea. Species There are currently seven recognized species in this genus: * '' Microchirus azevia'' ( Brito Capello, 1867) (Bastard sole) * '' Microchirus ...

azevia''), the Klein's sole (''Synapturichthys kleinii''), the

sand sole The sand sole (''Pegusa lascaris'') is a fish species in the family Soleidae. It is a marine, subtropical, demersal fish up to long. Widespread in the northeastern and southeastern Atlantic, to the Gulf of Guinea in the south, also in the Medi ...

(''Pegusa lascaris'') and the

Portuguese sole ''Dagetichthys lusitanicus'', commonly known as the Portuguese sole, is a species of flatfish native to the eastern Atlantic Ocean. Little is known of the abundance or behaviour of this fish, and the International Union for Conservation of Nature ...

(''Dagetichthys lusitanica''). In the English Channel, small common sole may have one or two leeches on them while large fish may have forty or more of the parasites. Adult leeches attached to the underside of fish lay eggs on the seabed in locations where the fish like to semi-bury themselves in the sediment; the eggs have stalks and are anchored to grains of sand. The free-swimming larvae search out a host fish and attach to the anterior end of the dorsal surface, the only part of the fish not buried in sediment. After a short period of development, the larvae migrate to the ventral surface of the fish. Here they attach to the host with their front sucker oriented towards the front of the fish.

References

{{Taxonbar, from=Q55613603 Leeches Fauna of the Atlantic Ocean Animals described in 1863