Tetilla polyura Schmidt, 1870 (Fig. 5a-g)next section
Tetilla polyura Schmidt, 1870: 66, pl. 6 fig. 8
Fig. 5. Tetilla polyura Schmidt, 1870, ZMA Por. 02362, a habitus of fragment (scale bar 1 cm); b-g SEM images of spicules; b oxea, b1 details of oxea; c anatriaene, c1 detail of cladome of anatriaene; d ‘normal’ protriaene; e cladomes of ‘2+1’ protriaenes; f sigmaspire; g dragma of raphides/oxeotes, g1 detail of dragma..
Material. ZMA Por. 02362, Russia, Kara Sea, Varna Expedition, locality not noted on the available labels, depth between 75 and 170 m, coll. J.M. Ruijs, 1882-1883. Label text: ‘Bruchstück wahrscheinlich Tetilla polyura O. Schm., KKY‘ + illegible small label, possibly original.
Description. A dark brown, conical-shaped fragment (Fig. 5a), spinous, firm condition.
Spicules. (Fig. 5b-g) Oxeas, anatriaenes, protriaenes,, sigmaspires, raphides.
Oxeas (Fig. 5b, b1) in two rather sharply divided categories, (1) long, thin and flexuous with gradually tapering thin apices, usually broken in the slides, largest unbroken oxea up to 4200 × 7 µm, (2) short, fusiform, 600-1080 × 12-19 µm.
Anatriaenes (Fig. 5c, c1), common, with long wispy shaft, usually broken, up to 2100 × 8 µm. Cladomes narrow, 29-63 µm in diameter, cladi 28-81 × 4-8 µm.
Protriaenes, shafts thin and wispy, 960-1600 × 3-10 µm, in two types, (1) normal shaped cladomes (Fig. 5d), and (2) with ‘2+1’ cladomes (Fig. 5e), long cladus 88-225 × 3-7 µm, short cladi 24-78 × 3-5 µm.
Sigmaspires (Fig. 5f), C or S-shaped, faintly centrotylote, 10-13 µm.
Raphides/oxeotes (Fig. 5g, g1), sinuous or wispy, in trichodragmas or frequently single, length 215-345 µm, thickness around 1 µm.
Remarks. The fragment conforms to Schmidt’s description and figure as far as the spicules are concerned (both anatriaenes and protriaenes present). The outer morphology deviates in lacking the conical surface elevations, but that can be attributed to the fragmentary condition of the specimen. There is considerable similarity in the spiculation with Tetilla sandalina Sollas, 1886 (see below), but that species lacks anatriaenes.
Tetilla sandalina Sollas, 1886 (Fig. 6a-f)
Fig. 6. Tetilla sandalina Sollas, 1886, ZMA Por. 02353, a habitus of four fragments presumed to be from a single specimen (scale bar 1 cm); b-f SEM images of spicules; b long thin oxea, b1 details of apices of long thin oxea; c short fusiform oxea, c1, details of apices of short oxea; d ‘2+1’ protrianee, d1 details of cladome and pointed end of a ‘2+1’ protriaene; e sigmaspires; f raphide.
Material. ZMA Por. 02353, Russia, Kara Sea, Varna Expedition, locality not noted on the available labels, depth between 75 and 170 m, coll. J.M. Ruijs, 1882-1883. Label text: ‘Tetilla cranium (Müller)’ no further text, no identifier.
Description. The sample consists of five fragmentary specimens (Fig. 6a) which may be part of a single larger specimen. One fragment is attached to a shell. Color grey-brown, surface very spinous-hairy, condition firm.
Skeleton. Radiate, predominantly made up of the shorter oxeas.
Spicules. (Fig. 6b-f) Oxeas, protriaenes, raphide-like oxeas, sigmaspires.
Oxeas in two overlapping categories, (1) long, with gradually tapering thin apices (Fig. 6b, b1), usually broken in the slides, largest unbroken oxea up to 3900 × 36 µm, (2) short, fusiform (Fig. 6c, c1), 600-1260 × 12-21 µm.
Protriaenes (Fig. 6d, d1), with ‘2+1’ cladomes, shaft thin and wispy, 1260-2900 × 2-6 µm; long cladus 22-147 × 1.5-4 µm, short cladi 15-51 × 1-3 µm.
Sigmaspires (Fig. 6e), C or S shaped, distinctly centrotylote, 10-16 µm.
Raphides/oxeotes (Fig. 6), sinuous or wispy, in trichodragmas or frequently single, length 320-400 µm, thickness around 1 µm.
Remarks. Cárdenas and Rapp (2015) described a specimen of this species from the adjacent Barents Sea and their spicule size data are closely similar to the above cited with the exception of the sigmaspires, which were 15-25 µm. A major discrepancy with previous records, including those of Cárdenas and Rapp (2015) is the depth, at which the present fragment was collected. The precise depth is unfortunately not known, but the dredgings of the Dutch Polar Expedition did not exceed 200 m in depth. Most of the dredgings were done between 70 and 125 m (Ruijs, 1887). The species shares with T. polyura (see above) the ‘2+1’ protriaenes, but differs in the absence of anatriaenes.