Van Soest and Stone, 1986
Species Overview
Antho brattegardi Van Soest and Stone, 1986 is a thinly encrusting orange microcionid, which can only be reliably identified from a microscopical examination of the spicules. It has a unique feature in the possession of numerous crocae (tiny walking stick-like spicules); otherwise it is most closely related to Antho coriacea . It has been found only once in the Norwegian fjords at 35-45 m depth.
Taxonomic Description
Colour: Orange (cream in alcohol).
Shape, size, surface and consistency: Thinly incrusting on barnacles: surface microhispid, oscules not apparent, size several mm2, uniformly about 1 mm thick. Consistency fragile, crumbly.
Spicules: (Antho brattegardi spics) Megascleres : Ectosomal subtylostyles with microspined heads: 220-410 by 3-5 µm; choanosomal smooth styles, almost straight: 442-765 by 8 µm; choanosomal smaller styles with acanthose heads, almost straight-shafted: 160-195 by 10 µm; choanosomal acanthostrongyles of primary tracts, entirely but sparsely spined: 90-115 by 2-8 µm; choanosomal acanthostrongyles of connectives, entirely but sparsely spined, often more pronounced at the ends, very slightly curved shaft: 125-130 by 2-8 µm.
Microscleres : Palmate isochelae: 17-24 µm (Antho brattegardi chela); toxas in two size categories: 140-160 µm and 30-40 µm; J-shaped spicules (crocae): 10-14 by 0.5 µm (croca).
Skeleton: Ectosomal : hispid due to large choanosomal styles piercing the organic skin, which is strengthened by tangential bundles of subtylostyles. Choanosomal : a basal anisotropic reticulation of acanthostrongyles forming a rectangular mesh; sides of mesh of unequal length, i.e. ascending primary tracts composed of 2 or 3 smaller acanthostrongyles, reinforced by long overlapping styles, connected by 1 or 2 larger acanthostrongyles, forming the connectives, a spicule length in width; brushes of 2 or 3 larger slightly diverging smooth styles project at the surface; they are the terminal continuations of the choanosomal primary tracts, and span an askeletal zone (though filled with cells and mesohyl) covering ca. 1/3 body depth, before they pierce the surface; the primary tract configuration gives a scalariform pattern to the skeleton: spongin is present at the nodes.
Ecology: The single specimen was scraped off barnacle-encrusted stones at 35-45 m, bottom few large stones, exposed to occasional strong currents.
Distribution: Known only from the Bergen area, Norway.
Etymology: Named after Torleiv Brattegard, Director of the Bergen Marine Station during the 80's.
Type specimen information: The holotype is in the Amsterdam Museum, ZMA POR. 5190, N of Björöy, 60°20'N 15°10'3"E. A schizotype is deposited in the Natural History Museum, London, BMNH 1982:9:6:1.
Remarks
The distinctive feature of the present species is the J-shaped spicule, for which the name 'croca' is proposed, derived from Medieval English 'crok(e)', meaning shepherd's crook, based on Scandinavian or Icelandic krok(r)' = hook. Similar spicules are known from Californian Antho jia De Laubenfels, 1930. The genus Jia De Laubenfels, 1930 was founded especially on the crocae in combination with an otherwise microcionid spicule complement. We do not think that the crocae constitute a generic character in spite of the fact that a second species with approximately the same spicule complement has now been found. In other characters, such as the architecture of the skeleton, both species agree with Antho and neither can be differentiated from the remaining species of that genus.
A species extremely close to A . brattegardi , if we disregard the crocae, is A . coriacea . It is a red, orange or yellow, thinly incrusting sponge occurring commonly on the Atlantic coasts of Europe. It differs in the presence of spination on the toxas (which is also present in A . jia and several Clathria species) and in the individual spicule sizes. Like the present species A . coriacea shows the 'Plocamilla '-type of skeletal specialization with reinforcing overlapping acanthostyles. In our opinion this difference between 'Plocamilla ' and Antho is not of generic level. However, a careful revision of 'plocamiform' microcionid genera, which differ from Clathria by the possession of a renieroid spicule reticulation (including Antho , 'Plocamilla , 'Jia ' and Heteroclathria) , is perhaps necessary as a firm basis for this conclusion.
Another related species seems to be A . circonflexa from the south coast of Bretagne; it differs primarily in the presence of twisted chelae, a featured shared with several other microcionids.
Source: Van Soest and Stone, 1986.