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(Johnston, 1842)

Species Overview

Leucandra fistulosa (Johnston, 1842) forms single whitish, brittle tubes with a warty or spiny surface. The tubes are seldom straight, mostly curved, sometimes somewhat flattened. It resembles the common Sycon ciliatum but has a "naked" oscule in stead of a fringe of long spicules. It is an ill-known species, not recently recorded.

Taxonomic Description

Colour: White.
Shape, size, surface and consistency: Single tubes of up to 8 cm high. It is usually somewhat curved, seldom straight, often somewhat compressed. Surface warty, spiny. Apical oscule 2-5 mm in diameter, "naked" (no fringe of long spicules).
Spicules: (leucandra_fistulosa_spics.jpg) Calcareous. Triactines mostly sagittal, seldom regular or irregular, with basal ray: 400-500 µm and lateral rays: 300-400 x 5-10 µm; regular triactines with rays: 400 x 8 µm.
Tetractines similar in shape and size as the triradiates, with long thin apical ray: 350-450 x 4-6 µm.
Oxeas: 2000-5000 x 20-30 µm.
Skeleton: Leuconoid structure. Main mass of spicules is made up of slim, sagittal and irregular triactines; sagittal tetractines at the gastral surface, with very thin long, slightly curved apical rays; large oxeas penetrate the outer surface and project beyond it.
Reproduction: August-September.
Ecology: From shallow-water down to 180 m.
Distribution: North Atlantic: Straits of Dover, Plymouth, W and N Ireland, Shetlands, Norway.
Etymology: The name refers to the habit.
Type specimen information: Type: BMNH 1847.9.7.78 (dry + slide) (as Leucandra). Johnston Collection.

Remarks

This resembles Leuconia johnstoni, but that species has the tubes connected by a common massive base. Leucandra aspera is much more "hairy". From Sycon ciliatum and S. scaldiense it differs in lacking a fringe of long spicules surrounding the apical oscule.
Source: Arndt, 1935.

Leucandra fistulosa