Stylostomum ellipse ( Dalyell 1853 ) Lang, 1884

Faubel, A. & Warwick, R. M., 2005, The marine flora and fauna of the Isles of Scilly: Free-living Plathelminthes (‘ Turbellaria’), Journal of Natural History 39 (1), pp. 1-45 : 23-24

publication ID

https://doi.org/ 10.1080/00222930310001613593

persistent identifier

https://treatment.plazi.org/id/5F1587FE-FFF0-A031-FEF1-95E4FD0A3F01

treatment provided by

Carolina

scientific name

Stylostomum ellipse ( Dalyell 1853 ) Lang, 1884
status

 

Stylostomum ellipse ( Dalyell 1853) Lang, 1884

( Figure 6 View Figure 6 )

Planaria ellipsis Dalyell, 1853: 101–102 , pl. XIV: 9–16.

Stylochus roseus M. Sars in Jensen, 1878: 75, pl. VIII: 1–3.

Stylostomum υariabile Lang, 1884: 585–588, pl. 8: 3, 4, 6.

Stylostomum sanguineum Hallez, 1893: 180–182 , pls III: 10, IV: 12–14.

Stylostomum antarcticum Hallez, 1905: 126 .

Stylostomum punctatum Hallez, 1905: 126 .

Material examined

Voucher specimen: site 8, one specimen, sagittally sectioned series of a sexually immature specimen. Same specimen in live observation stored on CD-ROM: 2003.6.6.4.

Geographical distribution. Arctic Ocean: Norway (Spitzbergen: Eisfjord); North Sea: Scotland (Firth of Forth: St Andrews); Skagerrak: Norway (Oslofjord: Hallangspollen), Sweden (Gullmarfjord, Halse Fjord); English Channel: England (Plymouth Sound, Falmouth); Irish Sea: Isle of Man (Port Erin), Ireland (Co. Dublin: Malahide shore); NE Atlantic: Ireland (Co. Donegal: Lough Swilly, Co. Mayo: Clew Bay, Co. Galway, Co. Kerry: Valentia Harbour); SE Atlantic: South Africa (Cape Town); SW Atlantic: Falkland Islands (Port William, Berkeley Sund), Tierra del Fuego (Cape Virgenes, Ushuaia); Mediterranean Sea: Tyrrhenian Sea: Gulf of Naples; Adriatic Sea: Gulf of Trieste ( Lang 1884; Plehn 1896; Micoletzky 1910; Bock 1913; Marine Biological Association of the United Kingdom 1957; Faubel 1984).

Description

Length of body 3.4 mm, width 1.4 mm; terminal ends broadly rounded, tapering slightly anteriorly, with smooth dorsal surface ( Figure 6 View Figure 6 ). Colour yellowish white in incident light; in transmitted light, margins transparent but central body dark yellowish brown when gut diverticula full of food. Marginal tentacles less prominent forming mere blunt projections of the margin, with eye clusters at their base (8–10) and a few eyes (four) in between. Cerebral eyes in bilateral clusters above brain, each with 9–11 eyes ( Figure 6 View Figure 6 ). Two characteristic pairs of eyes at the posterior margin of brain. Cylindrical pharynx immediately behind brain; intestinal trunk extending from proximal pharynx to hind end with nine pairs of intestinal lateral branches; frontal median branch of intestine extends dorsally of the pharynx to the anterior end (not drawn in Figure 6 View Figure 6 ). Sucker in mid-body. Specimen not sexually mature.

Remarks

To date five valid species of the genus Stylostomum are known. Of these only Stylostomum ellipse is known from European Seas. All the other species were recorded from the Southern Ocean (Iles de Kerguelen: S. frigidium Bock, 1931 ) and Pacific Ocean. S. ellipse is obviously highly variable in colour depending on uptake of food. That variability led Lang (1884) to describe S. υariabilis as a synonym of S. ellipse . The characteristic determination features of S. ellipse are the frontal branch of the intestine, the typical arrangement of eyes, especially the two characteristic pairs of eyes at the posterior margin of the brain ( Lang 1884), and the tentacles formed as blunt marginal projections. In these characters the juvenile polyclad specimen recorded at site 8 agrees well with S. ellipse .

Kingdom

Animalia

Phylum

Platyhelminthes

Class

Rhabditophora

Order

Polycladida

Family

Euryleptidae

Genus

Stylostomum

Loc

Stylostomum ellipse ( Dalyell 1853 ) Lang, 1884

Faubel, A. & Warwick, R. M. 2005
2005
Loc

Stylostomum antarcticum

Hallez P 1905: 126
1905
Loc

Stylostomum punctatum

Hallez P 1905: 126
1905
Loc

Stylostomum sanguineum

Hallez P 1893: 182
1893
Loc

Stylostomum

Lang A 1884: 585
1884
Loc

Stylochus roseus

Jensen OS 1878: 75
1878
Loc

Planaria ellipsis

Dalyell JG 1853: 102
1853
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