Amphilectus cf. fucorum (Esper, 1794)

Van Soest, Rob W. M., Beglinger, Elly J. & de Voogd, Nicole J., 2012, Sponges of the family Esperiopsidae (Demospongiae, Poecilosclerida) from Northwest Africa, with the descriptions of four new species, European Journal of Taxonomy 18, pp. 1-21 : 9-11

Amphilectus cf. fucorum (Esper, 1794)

Fig. 5

For synonymy, see Van Soest & Hajdu 2002b: 657.

Material examined

ZMA Por. 06775, Mauritania, off Banc d’Arguin, depth 100 m, bottom muddy sand, coll. R.W.M. Van Soest & J.J. Vermeulen, Mauritania II Exped. Stat. 072/14, 20.0°N 17.3°W, 2.4 m Agassiz trawl, 13 Jun. 1988. ZMA Por. 06796, Mauritania, off Banc d’Arguin, depth 48-52 m, bottom muddy sand with some calcareous gravel, coll. R.W.M. Van Soest & J.J. Vermeulen, Mauritania II Exped. Stat. 082/19, 19.9833°N 17.5°W, 3.5 m Agassiz trawl, 14 Jun. 1988. ZMA Por. 06843, Mauritania, off Banc d’Arguin, depth 95-100 m, bottom muddy sand with shells, coll. R.W.M. Van Soest & J.J. Vermeulen, Mauritania II Exped. Stat. 130/09, 20.4167°N 17.6667°W, 3.5 m Agassiz trawl, 20 Jun. 1988.

Description

The material consists of several fragments of encrusting to irregularly ramose sponges ( Fig. 5A ). Consistency, soft irregular surface, colour brownish alive and beige to whitish in alcohol. Size of individual fragments 2-3 cm.

SKELETON. Irregularly plumoreticulate ( Fig. 5B ), with loosely defined spicule bundles connected by individual spicules, general aspect rather confused. Spicules barely protruding beyond the surface. Chelae clustered and singly occurring throughout the interior.

SPICULES. Styles, palmate isochelae.

STYLES. ( Fig. 5C, C 1 ) Straight or slightly curved, relatively short and robust, 198- 237.6- 276 x 9- 11.4 - 14 µm.

PALMATE ISOCHELAE. ( Fig. 5D ) Of ‘normal’ shape, but like in A. utriculus sp. nov., the shaft is slightly incurved. 19- 23.6 - 27 µm.

Distribution and ecology

Mauritania, off Banc d’Arguin ( Fig. 1 , loc. 2), on muddy bottom below 50 m. Elsewhere, if identification is correct, along most of the coasts of Europe, including the Western Mediterranean. This is the southernmost record of the species if Southern Ocean records (see below) are considered not conspecific.

Remarks

By assigning these specimens to A. fucorum , the range of this species, which was already huge, is further extended along the East Atlantic coasts. The species is common and distinctly orange-coloured in shallow water habitats of the British Isles and the W coast of France, but according to Van Soest et al. (2000) deep-water specimens may loose their colour, and such specimens may be found down to 100 m. Skeleton and spicule characteristics of the present material fall within the recorded variation, although usually styles elsewhere are thinner than those of the Mauritanian specimens. Genetic comparisons may show diversity over the range of this species and such studies are needed to decide the specific identity of the Mauritanian populations.

From the other Amphilectus species from the area described above, A. cf. fucorum differs in habit and chelae ( A. utriculus sp. nov. has chelae twice the size, A. strepsichelifer sp. nov. has chelae with a twisted shaft).

Amphilectus informis (Stephens, 1915) from the Atlantic coast of South Africa appears to be similar based on published data. According to the original description its chelae have an incurved shaft but apparently the frontal alae of the chelae are characteristic showing a ‘tubercle in front view’. However, the illustration of this feature is indistinct. Samaai & Gibbons (2005) described the species also, but their illustrations do not clarify these alleged differences.

Burton (1932, 1940) recorded A. fucorum from Tristan da Cunha, the Falkland Islands, South Georgia, and off the coast of Argentina. Thiele (1905) recorded it from Chile. Goodwin et al. (2011) described two new Amphilectus species from the Falkland Islands, which appear to cover the Burton and Thiele records. Bergquist & Fromont (1988) recorded the European species Esperiopsis normani (Bowerbank, 1866) and Esperiopsis edwardii (Bowerbank, 1866) from New Zealand waters, but both are now considered junior synonyms of Amphilectus fucorum . This is not to say that A. fucorum occurs in New Zealand, but merely that these records should be compared critically.

Figures

Fig. 5. Amphilectus fucorum (Esper, 1794), ZMA Por. 06775. A. Habit (fragments). B. Cross section of skeletal reticulation. C-D. SEM images of spicules. C. Style. C1. Details of apices. D. Palmate isochela.

Fig. 1. Map of Northwest Africa, showing the approximate localities from which the sponges were collected. 1. Mauritania, Cap Blanc. 2. Mauritania, Banc d’Arguin. 3. Mauritania, SW of Cap Timiris 4. Cape Verde Islands, São Vicente 5. Cape Verde Islands, Ilheu de Cima.