Grantia kempfi Borojevic & Peixinho, 1976,

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225: 205-207

publication ID

http://doi.org/ 10.5281/zenodo.272951

publication LSID

lsid:zoobank.org:pub:6D68A019-6F63-4AA4-A8B3-92D351F1F69B

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http://treatment.plazi.org/id/03A80010-779B-FF62-FF14-A3F394C1FB5F

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Plazi

scientific name

Grantia kempfi Borojevic & Peixinho, 1976
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Grantia kempfi Borojevic & Peixinho, 1976 

Figures 130View FIGURE 130 a –d, 131a –h

Grantia kempfi Borojevic & Peixinho, 1976: 1019  , figs 19–20.

Material examined. RMNH Por. 9941, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 63, 7.5833°N 57.0667°W, depth 71 m, sandy bottom, 31 August 1970GoogleMaps  .

Description. ( Fig. 130View FIGURE 130 a) Tubular sycon-like sponge, with coarsely spined surface and prominent apical fringe. Length 1.5 cm, diameter 0.5 cm at its widest thickness. Color in alcohol dirty white, fringe shiny white. Consistency firm.

Skeleton. ( Figs 130View FIGURE 130 b –d) Syconoid structure ( Fig. 130View FIGURE 130 b). Cortical ectosomal skeleton ( Fig. 130View FIGURE 130 c) consists of a layer of ‘curly’ triactines with characteristically curved unpaired actine, among which giant diactines protrude far beyond the surface. The chamber layer is a regular system of tubar triactines and a minority of tetractines, aligning the choanocyte chambers with unpaired actine directed outwards. Subatrial triactines distinguished from the tubar triactines by their longer unpaired actines. Atrial skeleton ( Fig. 130View FIGURE 130 d) a mixture of tri- and tetractines, the latter having their apical actines protruding in the atrial cavity. The skeleton of the fringe consists of long thin diactines, the region of attachment to the main body is supported by T-shaped triactines distinct from the tubar, cortical and atrial triactines.

Spicules. ( Figs 131View FIGURE 131 a –h) Giant diactines, fringe diactines, at least four types of triactines, tetractines.

Giant diactines ( Fig. 131View FIGURE 131 a) of the cortical region, asymmetrically fusiform, in a large size range, 168– 727 – 1320 x 15 – 32.6 –51 µm.

Cortical triactines ( Figs 131View FIGURE 131 b), irregularly three-dimensional, with unpaired actines strongly curled, paired actines almost in one plane, rather uniform in size, unpaired actines 57– 106 –129 x 5.5– 6.6 –8 µm, paired actines 54– 73 – 89 x 5 – 6.3 –7.5 µm.

Tubar triactines ( Fig. 131View FIGURE 131 c), with paired actines at a low angle, tending towards being T-shaped, unpaired actines 96– 112 –138 x 7 – 8.2 –9 µm, paired actines 63– 76 – 91 x 6 – 6.8 –8 µm.

Tubar tetractines ( Fig. 131View FIGURE 131 d), with paired and apical actines at a low angle like those of the triactines, unpaired actines 87– 97 –130 x 5 – 5.8 –7, paired actines 57– 92 –105 x 5 – 5.5 –6.5, apical actines 15– 20 – 29 x 3 – 4.4 –6 µm.

Subatrial triactines ( Fig. 131View FIGURE 131 e), sagittal, with curved paired actines, rather uniform in size, unpaired actines 151– 159 –168 x 6.5– 7.4 –8.5 µm, unpaired actines 88– 103 –126 x 5 – 5.4 –6 µm.

Atrial triactines ( Fig. 131View FIGURE 131 f), sagittal, unpaired actines 61– 89 –135 x 6 – 6.3 –7 µm, paired actines 51– 77 –105 x 5 – 5.6 –6.5 µm.

Atrial tetractines ( Fig. 131View FIGURE 131 g), sagittal, largely similar in size and shape to atrial triactines but slightly larger, unpaired actines 60– 123 –195 x 5 – 6.4 –8 µm, paired actines 78– 101 –117 x 4.5– 6.3 –8 µm, apical actines 15– 30 – 66 x 3 – 4.6 –6 µm.

Diactines of the fringe ( Fig. 131View FIGURE 131 h,h1), long, straight, thin, slightly asymmetrical in thickness, 1495– 1748 – 2040 x 3 – 7.6 –12 µm.

Triactines of the oscular membrane ( Fig. 131View FIGURE 131 i), paired actines longer than unpaired actines, with broader outline, T-shaped, unpaired actines 123– 164 –192 x 4.5– 5.7 –8 µm, paired actines 141– 179 –219 x 5 – 7.3 –10 µm.

Distribution and ecology. Guyana Shelf, NE Brazil, on sandy bottoms at 19–71 m depth.

Remarks. Shape and general skeletal characters match closely with the type material from Pernambuco, NE Brazil. Borojevic & Peixinho (1976) (p. 1021) interpreted the curiously curved triactines as ‘triactines des ostioles’. However, this is not my interpretation, as these spicules are numerous and form a distinct cortical layer over the triactines of the chamber region. The spicules with shorter actines indicated as cortical triactines by Borojevic & Peixinho are grading into those lining the choanocyte chambers. They are quite variable with respect to the length of the unpaired actines, and in my opinion belong to the subcortical upper layer of the chamber region. Furthermore there are slight differences in the size ranges of the various spicule types. Nevertheless, I am confident that the more northern and deeper occurrence of the species is well established by the present material. 

RMNH

National Museum of Natural History, Naturalis

Kingdom

Animalia

Phylum

Porifera

Class

Calcarea

Order

Leucosolenida

Family

Grantiidae

Genus

Grantia

Loc

Grantia kempfi Borojevic & Peixinho, 1976

Van, Rob W. M. 2017
2017
Loc

Grantia kempfi

Borojevic 1976: 1019