Chenendopora piaskovskii, Pisera, 2000

Pisera, Andrzej, 2000, New species of lithistid sponges from the Paleogene of the Ukraine, Zoosystema 22 (2), pp. 285-298 : 293

Chenendopora piaskovskii n. sp.

( Figs 2 E-H; 5)

MATERIAL. — Holotype, fragmentary specimen NHM ZN1; paratype, fragmentary specimens NHM ZN11. ETYMOLOGY. — To honour the discoverer of this sponge fauna, geologist B. V. Piaskovsky.

DIAGNOSIS. — Plate-like or flabellate tetracladine sponge with small tuberculated tetraclones in the choanosomal skeleton and dermalia as small phyllotriaenes with pointed clad tips. Upper surface with numerous large canal openings running obliquely into the wall. Lower surface smooth with much smaller evenly distributed canal openings.

DESCRIPTION

These are fragments of plate-like or leaf-shaped sponge up to 10 × 6 cm large and with wall about 1 cm thick that thins toward the edge. Lower side more or less smooth with traces of concentric growth and irregular narrow elevations. It displays irregularly distributed rounded openings about 0.24-0.30 mm in diameter, which are loosely spaced. The upper side, which is slightly eroded in all specimens, displays large canal openings 0.6-0.8 mm in diameter, and canals which run close to the surface to enter after some distance obliquely the wall. These canals and their openings are arranged in irregular vertical (radial) series giving an appearance of irregular radial striation. Skeleton very dense, composed of stout and strongly tuberculated tetraclones 400- 700 µm in size (average 600 µm). These tubercles in most cases are oval or elongated. Dermal skeleton preserved only in few places, composed of very small and poorly branched phyllotriaenes with pointed tips of clads, and cladomes 270- 360 µm in diametre. Rhabd short, conical.

REMARKS

These are, most probably, the specimens which were erroneously considered by Oakley (1942) as representatives of the genus Corallistes . This is the first report of the Cretaceous genus Chenendopora from the Tertiary. The new species differs from other species of this genus in more regular and differently sculptured desmas, in the presence of dermalia (unknown in the Cretaceous forms) and in being rather leaf or plate-shaped than conical or cylindrical as other forms.

Figures

FIG. 2. — Habit of the investigated sponges; A-D, Theonella ukrainica n. sp.; A, NHM ZN10D; B, holotype NHM ZN5A; C, NHM ZN5E; D, NHM ZN5F; E-H, Chenendopora piaskovskii n. sp.; E, F, paratype NHM ZN11 in lower side (E) and upper side (F) views; G, H, holotype NHM ZN1 in upper (G) and lower side (H) views; I-K, Lerouxia digitata n. sp.; I, NHM ZN4; J, holotype, NHM ZN7; K, paratype, NHM ZN8; L, Plinthosella magna n. sp., holotype NHM ZN3, oblique view. Scale bars: A-D, G, H, L, 1 cm; E, F, I-K, 2 cm.