Filograna socialis (GOLDFUSS, 1831)

Kočí, Tomáš & Jäger, Manfred, 2013, Sabellid And Serpulid Worms From The Bohemian Cretaceous Basin (Upper Cenomanian - Middle Coniacian) Originally In The Collection Of Professor Antonín Frič, Acta Musei Nationalis Pragae Series B 69 (3 - 4), pp. 129-146 : 137

Filograna socialis (GOLDFUSS, 1831)

Pl. 1, fig. 2; Pl. 2, fig. 2

1831 1836 1845 1846

1875 1883 1961

1961 1973

1978

1979 1983

1984

2005 2012

Serpula socialis nobis; Goldfuss: p. 235, pl. 69, fig. 12 a–c. Serpula filiformis ; Sowerby in Fitton: p. 340, pl. 16, fig. 2. Serpula filiformis SOW ; Reuss: p. 20, pl. 5, fig. 26.

Serpula filiformis SOW. bei FITTON; Geinitz: p. 253, pl. 16, fig. 25.

Serpula socialis GOLDF ; Geinitz: p. 200, pl. 37, fig. 2.

Serpula socialis GOLDF ; Frič: p. 128, text–fig. 113.

Sarcinella socialis (GOLDFUSS, 1831) ; Regenhardt: p. 29, pl. 1, fig. 5.

Filograna sollistima n. sp; Regenhardt: p. 24, pl. 2, fig. 4. Sarcinella socialis (GOLDFUSS) ; Ziegler: p. 36, pl. 5, figs 4–6; pl. 6, fig. 1.

Sarcinella socialis (GOLDFUSS) ; Ziegler: p. 218, pl. 50, fig. 4.

Filograna plexus (SOWERBY, 1829) ; Lommerzheim: p. 128.

Filograna socialis (GOLDFUSS, 1831) ; Jäger: p. 20, pl. 1, figs 3–8.

Sarcinella socialis (GOLDFUSS, 1831) ; Ziegler: p. 219, pl. 2, figs 7–8.

Filograna socialis (GOLDFUSS, 1831) ; Jäger: p. 135.

Filograna socialis (GOLDFUSS) ; Kočí: p. 9, pl. 1, fig. 5.

M a t e r i a l. The original specimen figured by Frič (1883, pp. 128–129, fig. 113) from the Middle Turonian Iserschichten of Mladá Boleslav (Jungbunzlau), coll. National Museum, Prague, registration number NM O6051 .

D e s c r i p t i o n. A staghorn- or Y-shaped bundle composed of more than sixty tubes attached to each other and oriented more or less parallelly. All tubes have a smooth surface and are more or less circular in cross-section. The width of the right branch of the staghorn-shaped bundle is 11 mm, and height is 7.5 mm in oval cross-section Total length of the specimen is circa 30 mm. Tube diameter ranges from 1 to 1.8 mm.

R e m a r k s a n d r e l a t i o n s h i p s. Filograna filosa (DUJARDIN) forms similar staghorn-shaped bundles consisting of many tubes, but differs from F. socialis by its smaller tube diameter which is only 0.2–0.4 mm.

P a l a e o e c o l o g y. The staghorn-shaped colonial bundles composed of many thin-walled Filograna tubes growing more or less parallel to each other represent another adaptation for living on a soft substratum by forming ‘reeflets‘heavy enough to remain stable on a soft bottom, with the anterior portions of theirY-like dividing branches, as in staghorn corals, ascending above the sea-floor ( Seilacher et al. 2008, fig. 3C–D). However, in contrast to staghorn corals, the Filograna bundles not only divide, but sometimes unite to form a kind of ‘noose‘ or 3D ‘web‘. This is seen, for example, also in Frič’s original specimen. In the fossil state, such large web-shaped colonies are often found broken into cylindrical or Y-shaped fragments of bundles, and it is hard to distinguish if an isolated Y-shaped fragment represents a division or rather a uniting of bundles. More detailed remarks and discussion of relationships were published by Jäger (1983, 2005) and Kočí (2012).

O c c u r r e n c e i n B C B (data mainly from different volumes of Frič’s work and from Ziegler (1973, 1978). The genus Filograna is easily recognised by its bundle-shaped colony fragments consisting of many small parallel tubes, therefore it is very probable that locality data provided in the literature represent true occurrences of Filograna even if the specimens are neither described nor figured. Filograna socialis is widespread in the Middle Turonian of BCB and is especially common at Dolánky u Turnova, Klokočské Loučky, Jizerní Vtělno, Sychrov. General list: Lower Turonian – Kaňk. Middle Turonian – Dolánky near Turnova, Malá Skála, Klokočské Loučky, Vápeník near Turnov, Libuň, Železnice (quarry – “Na Váze”), Rovensko pod Troskami, Jizerní Vtělno, Sychrov, Mladá Boleslav, Benátky nad Jizerou, Kokořín, Brandýs nad Orlicí, Desná, Bezno near Zámostí, Čejtice, Česká Lípa, Choceň, Písník, Česká Třebová, Dalovice, Svitavy area.