Cementula sp.

Kočí, Tomáš & Jäger, Manfred, 2015, Sabellid And Serpulid Worms (Polychaeta, Canalipalpata, Sabellida, Sabellidae, Serpulidae) From The Rocky Coast Facies (Late Cenomanian) At Předboj Near Prague, Acta Musei Nationalis Pragae Series B 71 (1 - 2), pp. 31-50 : 34-35

Cementula sp.

Pl. 1, Fig. 11

2012b Cementula sp. – Kočí, p. 123, fig. 1L–M.

non 2012b Cementula sp. – Kočí, p. 120, fig. 1J–K.

M a t e r i a l: Twenty-two complete specimens and 12 fragments.

S u b s t r a t e: This species shows a tendency to form small clusters composed of several Cementula tubes attached to each other.

D e s c r i p t i o n. The tube is slightly depressed, has a wide basal seam, and forms somewhat irregular, more or less compact loops and coils, although rarely regular spirals, using its own anterior tube portions as a substrate. Except for a small and low but distinct median keel and a few alae-shaped peristomes present in some specimens, the surface of the tube is smooth and tends to obscure the boundary lines between the separate whorls by calcareous tube material laid over them. The umbilicus is narrow and often obscured by a filling of sediment. Internal tube structures (“ITS”; Pillai 1993) are absent.

R e m a r k s a n d r e l a t i o n s h i p s. Loops and coils are less regular compared to the regular spirals common in other Late Cretaceous Cementula species, e.g. C. spirographis (GOLDFUSS, 1831) and C. depressa (GOLDFUSS, 1831) , both from the Middle Cenomanian of Essen, and the single find of a Cementula spiral system from the Late Cenomanian of Saxony ( Jäger 2014); the two last mentioned forming large systems of planar spirals attached to large oyster valves. The spirals of Cementula sphaerica BRÜNNICH NIELSEN, 1931 from Middle Santonian to Late Maastrichtian are also more regular, planar or more or less hemisphaerical in shape, and most of them lack an umbilicus. The Late Campanian and Maastrichtian species of the closely related genus Spiraserpula REGENHARDT, 1961 differ by the presence of “ITS” ( Pillai 1993).

Fossil representatives of Spiraserpula and Cementula (e.g. Goldfuss 1831, Brünnich Nielsen 1931, Regenhardt 1961, Lommerzheim 1979, Jäger 1983, 2005, Pillai 1993) occur mainly in shallow-water facies including Late Cretaceous sites from rocky coast and coral reefs down to relatively shallow portions of chalk facies circa 200 m deep ( Lommerzheim 1979), Danian bryozoan limestone facies, and Danian non-zooxantellate coral facies ( Brünnich Nielsen 1931). The 19 Recent species (including one in open nomenclature) of the genus Spiraserpula were described in detail by Pillai and ten Hove (1994) who are also the authors of all Spiraserpula species mentioned below except S. massiliensis ( ZIBROWIUS, 1968) . Here we provide a compilation of their ecological data: Spiraserpula occurs at various depths and inhabits various substrates, but only a few species can be called deep water species, e.g. S. capeverdensis which lives around the Cape Verde Islands at depths of 75–200 m where the sea-floor consists of coarse sand, shell gravel, calcareous stones, calcareous nodules, calcareous algae and sponges. Both S. deltoides and S. sumbensis were found only near Sumba, Indonesia on calcareous stones at depths of about 75– 90 m. S. vasseuri was found on oyster shells in a submarine cave at a depth of 55 m near Europa Island in the Mozambique Channel. However, most Spiraserpula species live in warm shallow waters, e.g. S. massiliensis in the Mediterranean Sea and northeastern Atlantic and S. ypsilon near the Cape Verde Islands. In sheltered habitats (submarine caves, overhangs, under stones) they occur in shallow water down to circa 20 m, and on the open sea-floor (in Caulerpa meadows or/and on shells, calcareous algae and concretions) they live in circa 15–60 m, whereas finds at deeper sites are probably transported dead tubes. S. ypsilon and many other Spiraserpula species live in or near coral reefs from the intertidal (rock pools) to less than 50 m deep, many somewhat sheltered on the underside of rocks or coral debris, but some exposed to strong water action. Most species are not widely distributed geographically, some are even endemic to a small area. Among tropical coral reef sites inhabited by one or more Spiraserpula species, those situated in the Caribbean and in the Gulf of Mexico are mentioned most frequently, e.g. Bonaire, Curaҫao, Florida, and others, but also Indonesia (e.g. Flores Sea) and Australia (New South Wales, Queensland). S. caribensis is widely distributed in the Caribbean and Gulf of Mexico from Florida to Barbuda and Panama; it lives intertidally down to 10 m in the Caribbean and to 18 m in the Eastern Gulf of Mexico. It occurs in a variety of habitats, from rockpools to the undersides of boulders in mangrove glades; it survives well in somewhat muddy, but always cryptic environments between boulders, coral debris, shells or other solid substrates. S. snellii is a reef dweller, often attached to corals, it occurs at depths of 2– 30 m, and appears to be the most widely distributed species of the genus: northern Red Sea, Indonesia (Flores Sea), Australia (Great Barrier Reef), and Western Pacific (South Japan to New Caledonia).