Stenocuma graciloides

Stenocuma graciloides (G.O.Sars, 1894)

AUTHOR: A.E. Antsulevich
CITATION OF THIS ENTRY: Antsulevich A.E. 2004. Stenocuma graciloides. In: Baltic Sea Alien Species Database. S. Olenin, E. Leppakoski and D. Daunys (eds.).
INTERNET: http://www.corpi.ku.lt/nemo/mainnemo.html

TAXONOMY

	Subtypus	Invertebrata
	Class	Crustacea
	Order	Cumacea
	Family	Pseudocumidae
	Genus	Stenocuma (G.O.Sars, 1900)
	Species	Stenocuma graciloides (G.O.Sars, 1894)
	Synonyms:	Pseudocuma graciloides Sars, 1894; Pseudocuma (Stenocuma) graciloides M.Bechesku, 1969

Fig.1: Stenocuma graciloides G.O.Sars, 1894 (from Birshtein, Romanova 1968).

IDENTIFICATION

Diagnosis:

S. graciloides is very close to S. gracilis (G.O.Sars, 1894), as it was mentioned by other authors. From the latter S. graciloides is being distinguished by its longer and sharp pseudorostrum as well as its oblong carapace regarding the lengs of its free pectoral segments (Fig 1). As it refers from the literature, the length of the species individuals may reach 4-6mm.

INTRODUCTION AND DISTRIBUTION

First record from the Baltic Sea (year, area, reference):

Year - August 2004
Area - The Eastern Gulf of Finland

Established:

in the entire Baltic Sea - ?
in the area of primary introduction - ?

Origin of the species:

Stenocuma graciloides is widespread over the whole Caspian Sea, Volga delta, Don, Dnepr-Bug, Dnestr, Danube estuaries, Taganrog bay of the Sea of Azov. Inhabits the fresh and brackishwater silty-sandy and sandy bottoms.

Vector of introduction:

Regarding the fact that cumaceans S. graciloides easily stand desalination and even are able to reside in freshwater bodies, it is possible that they could overpass the way from the Caspian-Azov-Black Sea basin to the Gulf of Finland in the Baltic Sea by themselves or with numerous ships passing through this water corridor.

Distribution in the Gulf of Finland:

The only one specimen of the species was recorded - immature female of 2.5mm length.

THE ROLE IN THE GULF OF FINLAND ECOSYSTEM

Cumaceans spend their lives burying themselves into the bottom sediments, and feeding on detritus and bacterial coating on the sand grains. Concerning their occupied ecological and trophical niche it is unlikely that thay could have any negative ecological impact on the ecosystem.

REFERENCES

1. Antsulevich A.E. in print. First finding of Cumacea crustaceans in the Gulf of Finland. Vest. Sankt-Petersburg Univ., (3 Biol.), (in Russian with English summary).