Tetilla pentatriaena Fernandez, Peixinho, Pinheiro & Menegola, 2011

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 114-117

Tetilla pentatriaena Fernandez, Peixinho, Pinheiro & Menegola, 2011

Figures 70 a–i

Tetilla pentatriaena Fernandez et al., 2011: 53 , figs 2–3.

Material examined. RMNH Por. 9321, 9322, 9782, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station K104, 6.9133°N 54.4333°W, depth 55 m, Agassiz trawl, 12 April 1969 (15, 16 and 41 specimens) ; RMNH Por. 9329, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station B23B, 6.8°N 54.19°W, depth 45 m, Agassiz trawl, 12 April 1969 (16 specimens) ; RMNH Por. 9357, French Guyana, ‘Luymes’ Guyana Shelf Expedition, station 21, 6.05°N 53.2°W, depth 42 m, Agassiz trawl, bottom sandy mud, 26 August 1970 (1 specimen) ; RMNH Por. 9358, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 98, 6.7333°N 57.5333°W, depth 19 m, Agassiz trawl, bottom muddy fine sand, 3 September 1970 (3 specimens) ; RMNH Por. 9359, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 71, 7.25°N 57.2833°W, depth 25 m, Agassiz trawl, bottom sand, 31 August 1970 (1 specimen) ; RMNH Por. 9360, Guyana,‘Luymes’ Guyana Shelf Expedition, station 92, 7.1667°N 57.2°W, depth 35 m, Van Veen grab, bottom muddy sand, shells, 31 August 1970 (1 specimen) ; RMNH Por. 9361, Guyana,‘Luymes’ Guyana Shelf Expedition, station 77, 6.55°N 57.198°W, depth 29.6 m, Van Veen grab, 1 September 1970 (1 specimen) ; RMNH Por. 9362, Guyana,‘Luymes’ Guyana Shelf Expedition, station 72, 7.0833°N 57.2333°W, depth 31 m, Agassiz trawl, bottom muddy sand, shells, 31 August 1970 (1 specimen) ; RMNH Por. 9363, Guyana,‘Luymes’ Guyana Shelf Expedition, station 75, 6.7167°N 57.2833°W, depth 25 m, Agassiz trawl, bottom sand, 31 August 1970 (2 specimens) ; RMNH Por. 9729, French Guyana, ‘Luymes’ Guyana Shelf Expedition, station 22, 6.0°N 53.2333°W, depth 36 m, Van Veen grab, bottom calcareous sand, 26 August 1970 (1 specimen) ; RMNH Por. 9731, French Guyana, ‘Luymes’ Guyana Shelf Expedition, station 20, 6.1333°N 53.1333°W, depth 39 m, Van Veen grab, bottom fine calcareous sand, 25 August 1970 (2 specimens) ; RMNH Por. 9742, Suriname, ‘Luymes’ Guyana Shelf Expedition, station 43, 6.5167°N 53.9333°W, depth 35 m, Agassiz trawl, bottom shell gravel, 28 August 1970 (4 specimens) ; RMNH Por. 9745, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 120, 7.1°N 57.7167°W, depth 24 m, dredge, bottom muddy sand, 7 September 1970 (1 specimen) ; RMNH Por. 9777, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station I115, 7.21°N 54.8617°W, depth 81 m, triangular dredge, 24 April 1969 (1 specimen) ; RMNH Por. 9854 Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station M86, 6.6°N 54.0017°W, depth 42 m, bottom green mud and fine sand, 11 April 1969 (4 specimens) ; RMNH Por. 9855, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station L90, 6.8°N 54.19°W, depth 45 m, bottom sandy mud, clay, 12 April 1969 (1 specimen) ; RMNH Por. 9860, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station K103, 6.99767°N 54.4167°W, depth 63 m, sandy mud, clay, 12 April 1969 (1 specimen) ; RMNH Por. 9943, Guyana, ‘Luymes’ Guyana Shelf Expedition, station 63, 7.5833°N 57.0667°W, depth 71 m, sandy bottom, 31 August 1970 (1 specimen) ; RMNH Por. 10539, Suriname, ‘ Luymes O.C.P.S. II’ Guyana Shelf Expedition, station K102, 7.1883°N 54.3833°W, depth 81 m, bottom greygreen mud, 18 April 1969 (1 specimen) .

Description. Small, pear-shaped sponges ( Fig. 70 a), with a single apical oscule ( Fig. 70 a1) and spiny-hairy surface, anchored in the soft substrate by a long rhizoid. Size quite variable, 3–14 mm high, 2–10 mm in diameter. The apical oscule is up to 2–3 mm in diameter and has a naked rim. Color in alcohol shades of beige. Consistency firm.

Skeleton. At the surface there is a palisade of predominantly oxeas of longer and smaller sizes, along with some anatriaenes and protriaenes. From among this palisade, bundles of protriaenes protrude far beyond the surface, thus causing the sponges to be quite bristly. The choanosomal skeleton is made up of subectosomal bundles of megascleres of various types traversing in a spiral fashion towards the center of the sponge. From the center strong bundles of predominantly anatriaenes unite to form the root system consisting of loose bundles of anatriaenes and smaller oxeas. The choanosomal spicules are frequently provided with long, curled and wispy thin endings.

Spicules. ( Figs 70 b–i) Oxeas, prodi- and -triaenes, anatriaenes, sigmaspires.

N.B. As with Fangophilina submersa , the diversity and length of many of the triaenes precluded taking full measurements of a minimum of 15 of spicules. For that reason I present only the ranges.

Oxeas ( Figs 70 b–c) in a wide size range, in the section appearing to be up to 3 mm in length but in the spicule preparation these long spicules are invariably broken; the oxeas are divisible in two shapes, (1) asymmetrical ( Figs 70 b,b1), with one end fusiform and the other end thinly tapering, in the spicule slides measured to be 492– 1620 x 5–20 µm, and (2) symmetrical fusiform ( Figs 70 c,c1), in the spicule slides measured to be 600– 1260 x 8–24 µm.

Prodi- and –triaenes, quite variable in rhabdome length and cladome shape and length; the variability of cladome shape does not appear to be correlated with the size; three more or less distinct types can be distinguished, (1) with narrow cladome and straight, thick cladi ( Figs 70 d,d1), predominantly three-claded, one or two of which may be shorter, rhabdomes 1100– 1560 x 2–6 µm, cladomes 30–50 µm, cladi 30– 90 x 4–7 µm, (2) with wideflaring cladome ( Figs 70 e,e1), predominantly prodiaenes, rhabdomes 965– 1620 x 2–5 µm, cladomes 60–150 µm, cladi 110–155 x 2–7 µm, and (3) very small, thin ( Fig. 70 f), usually prodiaenes, with unequal cladi, 90–240 x 0.5–1 µm, cladomes 20–25 µm, cladi 12–30 x 0.5 µm.

Anatriaenes ( Figs 70 g–h), less variable than protriaenes, length of rhabdomes mostly not measurable due to broken condition, which is especially caused by the occurrence of a thinly developed part of the rhabdome just below the cladome between swollen parts above and below this narrow rhabdome part; two types of anatriaenes are apparent, (1) with relatively wide cladome, with evenly curved short cladi ( Figs 70 g,g1), rhabdomes (n = 3) 690– 1230 x 1 –2.5 µm, cladomes 30–48 µm, cladi 24– 37 x 2–7 µm, and (2) with narrow cladome ( Figs 70 h,h1), with more sharply curved cladi, rhabdomes (n = 5) 900– 1080 x 4–5 µm, cladomes 42–54 µm, cladi 36– 67 x 5–7 µm (according to Fernandez et al. 2011 the latter apparently occur in two length categories, shorter choanosomal anatriaenes and longer (up to 7 mm) anatriaenes from the root bundles).

Sigmaspires ( Fig. 70 i), C- or S-shaped, small and uniform, not heavily spined, 8– 10.7 –13 µm.

Distribution and ecology. Guyana Shelf, Northeast Brazil, sand and mud bottoms at 19–81 m depth (previously 10–35 m). With 115 specimens this is the commonest sponge species on the Guyana Shelf.

Remarks. The species was described only recently and since most features of the present samples conform to the description of the type and other Brazilian specimens by Fernandez et al. (2011), there is little doubt that the Guyana specimens are conspecific. The diversity of triaenes appears to differ slightly from the Brazilian specimens in the protriaenes/prodiaenes, as the Guyana specimens have the prodiaenes more prominently present, in shapes with very long thin cladi, and very small prodiaenes with strongly unequal cladi. In view of the large spicule diversity these differences appear minor.

Figures

FIGURE 70. Tetilla pentatriaena Fernandez, Peixinho, Pinheiro & Menegola, 2011, a, habitus of a selection of specimens from RMNH Por. 9872 (scale bar = 1 cm), a 1, a single enlarged specimen from RMNH Por. 9872 (scale bar = 1 cm), b – i, SEM images of spicules, b, asymmetrical oxea, b 1, details of a, c, symmetrical fusiform oxea, c 1, details of c, d – f, protriaenes and modifications, d, protriaene with narrow cladome, d 1, detail of cladome of d, e, prodiaene with flaring cladi, e 1, cladome of e, f, small thin prodiaene, g – h, anatriaenes, g, anatriaene with wide cladome, g 1, cladome of g, h, anatriaene with narrow cladome, h 1, cladome of h, i, sigmaspire.