Xenosiphon absconditus Saiz, 1984

Xenosiphon absconditus Saiz, 1984

General description:

This species has only one difference from the congener species: it lacks the elongate digitate trunk papillae in the middle third of the trunk.

Look alikes:

Xenosiphon branchiatus, except that X. absconditus lacks the elongate gill-like trunk papillae in the middle third of the trunk.

Morphology:

(From Saiz, 1984, Cutler and Cutler, 1985)

External anatomy

Introvert shorter than the trunk. Triangular papillae covering the first 4 mm of the introvert.

Trunk measuring 110-600 mm in length. The skin at the middle third of the trunk has short diagonal ridges overlaying the noncontinuous epidermal minicanals. Minicanals do not have elongate papillae.

Tentacular crown consists of rows of small digitate tentacles.

Internal anatomy

33-37 longitudinal muscles bands (LMBs).

A pair of nephridia posterior to the anus, up to 25% of the trunk length, partially attached to the trunk wall.

Brain bilobed with a dorsal short digitate process.

Two pairs of retractor muscles arise at the same level. The ventral retractor muscles (VRM) spread over 2-4 LMBs, and the dorsals spread over 11-13 LMBs.

A pair of thin protractor muscles (PM) arise from the trunk wall of anterior part of the trunk and are attached to the introvert in front of the brain.

Size:

Specimens up to 600 mm in trunk length (Cutler and Cutler, 1985).

Distribution:

Red Sea, Palau, and Burma (Saiz, 1984; Cutler and Cutler 1985).

Habitat:

Intertidal and shallow water (Cutler, 1994).

Thu, 2014-09-04 19:11 -- Gisele Y. Kawauchi
Xenosiphon absconditus Saiz, 1984

General description:

(From Saiz, 1984)

The holotype has no collection information. However, the paratype specimens have four labels, each with the same information indicating the collecting site to be “Mer Rouge”.

Thu, 2014-09-04 19:11 -- Gisele Y. Kawauchi
Xenosiphon absconditus Saiz, 1984

General description:

Types: Museum National d’Histoire Naturelle, Paris, France, MNHN (Saiz, 1984). The holotype was deposited in a separate tube inside the jar V25, and the paratype inside the jar V29 (Saiz, 1984).

Thu, 2014-09-04 19:11 -- Gisele Y. Kawauchi
Xenosiphon absconditus Saiz, 1984

General description:

According Cutler (1994) this species was described based on two incomplete specimens from the Paris Museum, which had been previously identified as Sipunculus gravieri. However, in the original description of X. absconditus, Saiz (1984) stated that the species was described based from complete specimens from two different jars. In the first jar there was one complete specimen, dissected in the first third of the trunk, which he designated as the holotype, and a piece of a second specimen, which was impossible to identify (Saiz, 1984). The label of this first bottle, says: “Sipunculus gravieri Hér.”. A second jar contained one dissected specimen, which Saiz (1984) designated as paratype, and four labels (first label: Sipunculus, Mer Rouge, Mr Jousseaume, Nº 14, 1894”; second label: “Mer Rouge, M Jousseaume, 1896”; Third label: “Sipunculus gravieri Hérubel”; fourth label: “Siponculus, Mer Rouge, 1894, M Jousseaume”) (Saiz, 1984).

Thu, 2014-09-04 19:11 -- Gisele Y. Kawauchi

Sipuncula

Sipuncula

Xenosiphon absconditus Saiz, 1984

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Xenosiphon absconditus Saiz, 1984

Xenosiphon absconditus Saiz, 1984

Xenosiphon absconditus Saiz, 1984

Xenosiphon absconditus Saiz, 1984

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Sipuncula

Xenosiphon absconditus Saiz, 1984

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