Tetillopsis longitridens

Figure 1 - Tetillopsis longitridens (rk1143)
fractured spherical sponge.
Teutonia North, Misburg basiplana Zone

Figure 2 - Tetillopsis longitridens (rk1142)
hemisperical fragment with radiating needles, etched.
Teutonia North, Misburg vulgaris Zone

Figure 3 - Tetillopsis longitridens (rk1142)
close-up of etched specimen.
Note criss-crossed remains of smaller oxeas in the left part of the image.
Teutonia North, Misburg vulgaris Zone

Figure 4 - Tetillopsis longitridens (rk1142)
isolated triaenes and oxeas.
Teutonia North, Misburg vulgaris Zone

Synonyms:

none

Occurence:

Misburg, Upper Campanian. Very rare.

Oberg, Lower Campanian. Very rare.

Tetillopsis longitridens was described by Schrammen (1912) as a new species from the Lower Campanian of Oberg. Schrammen (1912) also defined a second Tetillopsis species, (T. doeringi) from the same locality, which seems to differ only in the size of its megascleres.

Several specimens of Tetillopsis are available to the author for study, all of which were assigned to Tetillopsis longitridens. They all display spherical habits. Distinct canal systems are lacking. See Figures 1 and 2. In the quarry, specimens are inconspicuos and are only discovered when broken, revealing their plumose skeleton structure.

The sponge fossils consist essentially of long, closely arranged, radiating triaenes and oxeas, embedded in sediment. These spherical megasclere structures are surrounded by haloes of very fine, dark coloured, criss-crossed oxeas, of which only traces (pyritized axial canals?) have been preserved. See Figure 3.

Figure 4 shows a selection of isolated megascleres.

The megasclere oxeas are fusiform and generally straight or slightly curved. When well preserved, an axial canal can be observed, which exits at both ends of the oxea.

The triaenes are simple protriaenes, without any signs of bifurcated clads. The shafts (rhabdoms) are long in relation to their cladomes. They taper towards their proximal end and show a swelling in their distal sections (not observed by Schrammen,1912).

Besides the very conspicuous megascleres, there are relics of numerous smaller, criss-crossed scleres, probably oxeas, which apparently formed a felted sheath around the spherical core of the sponge.