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(Bowerbank, 1866)

Species Overview

Haliclona (Gellius) angulata (Bowerbank, 1866) is a massively encrusting pale pink sponge, occasionally with fistular processes on the irregular and easily detachable upper surface. The consistency is firm, but brittle. It prefers rocks in places exposed to tidal currents.

Taxonomic Description

Colour: Light-purple alive, whitish semitransparant at the surface; dried yellowish-brown, in alcohol light purplish-brown or whitish.
Shape, size, surface and consistency: Massive, sometimes with fistular processes arising from the upper side of the sponge (Haliclona angulata BlandWh). Surface: smooth, even. Oscules few, rather large (ca. 0.5 cm), not elevated. Consistency: brittle, fragile.
Spicules: (Haliclona angulata micro) Megascleres: Oxeas straight or slightly curved, with a long and sharp point: 200-350 x 3.5-14 µm. Microscleres: Sigmata strongly curved, somewhat accolada-shaped, small: 7-15 x 0.2-1.2 µm. Toxas very slender, sharply bent, with recurved apices: 43-75 x 0.2-2.5 µm.
Skeleton: (Haliclona angulata skdraw) Ectosomal: a regular, isotropic reticulation of characteristically intercrossing oxeas (Haliclona angulata SEM). The ectosomal skeleton rests very loosely on the choanosomal skeleton, and is therefore easily peeled off, but consequently also easily damaged or lost. Choanosomal skeleton: sub-halichondroid, consisting of loosely organized paucispicular primary lines with irregularly scattered secondary spicules. Spongin: absent.
Reproduction: Larvae are cream with a bare ochre coloured posterior (Lévi, 1956)
Ecology: In the infralittoral, to 500 m.
Distribution: Shetlands, British Isles, Atlantic coasts of France and Spain, reaching
south to the Azores, Madeira and the Mediterranean.
Etymology: The name refers to the angulate toxas.
Type specimen information: Holotype of Halichondria angulata: BMNH 1910.1.1.173, Guernsey.
Holotype of Isodictya definita: BMNH 1930:7:3:360, Ilfracomb.
Holotype of Isodictya fallax: BMNH 1910:1:1:266, Guernsey.

Remarks

Haliclona (Gellius) angulata is characterized by the regular ectosomal skeleton of intercrossing oxeas, the strongly bent, angulated toxa and by the small, accolada-sigmata.
Isodictya indefinita and Isodictya fallax are without doubt conspecific with H. angulata. H. angulata has already been revised by Burton (1948), who also placed these two species in the list of synonyms, and recently by De Weerdt (1986). She does not agree with Burton's opinion to consider Isodictya jugosa Bowerbank and Halichondria couchii Bowerbank synonymous with H. angulata as well. These species are in her opinion conspecific with Haliclona (Gellius) fibulata (Schmidt, 1862). H. (G.) fibulata shares the skeletal architecture with H. (G.) angulata, but is morphologically well distinguished from it. It is well characterized by its thickly encrusting, laterally spreading habit, but especially by its strongly reticulate surface. H. (G.) fibulata can not be confused with any other species. Burton observed small, toxiform oxeas in I. jugosa, but these are juvenile oxea according to De Weerdt's observations (H. (G.) fibulata has only sigmata and no toxas; the sigmata are irregularly bent and larger than in H. (G.) angulata, viz. 10-37 µm). According to Burton the variations in size and shape of the sigmata are a normal feature of H. (G.) angulata. De Weerdt does not agree with this; according to her they are rather constant in shape and size.
Another species which Burton placed in the synonymy of H. (G.) angulata is Gellius ravus Stephens, 1912. Haliclona (G.) rava differs clearly from H. (G.) angulata by its habit (encrusting patches), the smaller oxeas (ca. 180 x 8.5 µm), the larger and much more irregularly bent toxas (38.5-120 x 0.2-1.6 µm), the smaller sigmata (4.8-12 x 0.2-0.5 µm), and by the presence of scarce spongin at the nodes of the spicules.
Topsent's (1901) record of Gellius angulatus quite certainly conforms to Haliclona (Gellius) marismedi (Pulitzer-Finali, 1978). This species has microtoxas in addition to the normal toxas (cf. de Weerdt and van Soest, 1986).
Topsent's (1904), Lundbeck's (1902), and Koltun's (1958) records of Gellius angulatus conform to Hemigellius arcofer (Vosmaer, 1885). This species has oxeas of 350-550 x 10-20 µm, sigmata in different size categories, the largest being ca. 80 µm, and toxas of 60-120 µm. The ectosomal skeleton is a strong reticulation of short paucispicular lines, which form rounded meshes. The choanosomal skeleton is also a strong, rigid reticulation of multispicular primary lines, which are irregularly connected by unispicular secondary lines. On the basis of the skeletal architecture the species belongs to the family Niphatidae van Soest (1980) (see Weerdt and van Soest, 1987).
Topsent's (1928) record of Gellius luridus conforms to H. (G.) angulata (cf. de Weerdt and van Soest, 1986). Gellius luridus Lundbeck (1902) belongs to the Niphatidae (see De Weerdt and van Soest, 1987).
The original material of Amorphina connexa has not been studied but Topsent's description and figure of the spicules (Topsent, 1888a: 144, pl. Vl fig. 15) conform to H. (G.) angulata, by his own admission (Topsent, 1892a: 76).
H. (G.) angulata is related to Reniera (= Haliclona) fibulata Schmidt, 1862 (Mediterranean-Atlantic), Gellius (= Haliclona) lacazei Topsent, 1893 (Mediterranean, south-eastern N Atlantic), Rhaphisia (= Haliclona) laxa Topsent, 1892b (Mediterranean-south-eastern N Atlantic), Rhaphisia (= Haliclona) spissa Topsent, 1892b (south-eastern N Atlantic), Isodictya (= ?Haliclona) tenera Marenzeller, 1877 (Arctic, transferred to Haliclona by Burton, 1959) and Gellius (= Haliclona) ravus Stephens, 1912 (?Mediterranean-Atlantic). All these species share the somewhat confused sub-halichondroid structure of the choanosomal skeleton, in places consisting of paucispicular primary lines. Haliclona tenera is the only species without microscleres. The megascleres of all these species are furthermore of a considerable size.
Source: De Weerdt, 1986

Haliclona angulata