Aspidosiphon thomassini

Aspidosiphon (Akrikos) thomassini Cutler & Cutler, 1979

Languages: English

Overview

General Description

This small worm may be misidentified as a Nephasoma species because the anal shield is overlooked or absent, and the smaller angle between the origin of the introvert and the anterior trunk. The introvert is up to 4 times the trunk length and apparently does not bear hooks and tentacles. Aspidosiphon thomassini has been collected in intertidal coral sand only in Madagascar and French Polynesia.

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

Type

Type Material

Type : Muséum national d’Historie naturelle, Paris, Cat. nº AF-406; BT Sta. 452; “devant labo., Ilo-Ilo, seagrass bed”. Paratype: Cat. nº AF-407; BT Sta. 419; Récif de Songoritelo”; Cat. nº AF-408; BT Sta. 136; “Grand Récif”, Tuléar.

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

Description

Morphology

(From Cutler & Cutler 1979, Cutler 1994)

External anatomy

Introvert is 2 to 4 times as long as the trunk, and arises in an angle of 40º to 45º with the main trunk axis.

This species appears to have neither tentacles nor hooks.

The anal shield is often poorly defined and variable. In those specimens in which it is developed, the anal shield is composed of small, scattered units that give the appearance of rough skin.

The caudal shield is absent.

 

Internal anatomy

The longitudinal muscle layer of the trunk wall is continuous.

Intestine attached posteriorly by spindle muscle.

Rectal caecum is absent.

Nephridia are about half of the trunk length, attached to the trunk wall almost their entire length, open slightly posteriorly to the anus.

A pair of retractor muscles, fused for most of their length, originates near but not at the posterior end of the trunk.

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

Size

This species is a small worm measuring between 1.5 to 7 mm long (Cutler & Cutler 1979).

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

Ecology and Distribution

Distribution

(From Cutler & Cutler 1979, Cutler 1994)

Reported only in Madagascar and French Polynesia.

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

Habitat and Ecology

(From Cutler & Cutler 1979, Cutler 1994)

Intertidal coral sand.

Author(s): Kawauchi, Gisele Y.
Rights holder(s): Kawauchi, Gisele Y.

References

Cutler, E. B. (1994).  The Sipuncula. Their systematics, biology and evolution. 453 pp. Ithaca, N.Y.: Cornell University Press.
Cutler, E. B., & Cutler N. J. (1979).  Madagascar and Indian Ocean Sipuncula. Bulletin du Museum National d'Histoire Naturelle, Paris. 4e, 941-990.