Distelopora spinifera, OSTROVSKY & TAYLOR, 2004

Ostrovsky, Andrew N. & Taylor, Paul D., 2005, Brood chambers constructed from spines in fossil and Recent cheilostome bryozoans, Zoological Journal of the Linnean Society 144 (3), pp. 317-361 : 324

DISTELOPORA SPINIFERA OSTROVSKY & TAYLOR, 2004

( FIGS 4B- D , 21D , 24P )

Material: NHM D21651-21653, D21667, D21894, D21897-D21899, D21901, D23308, Cretaceous, Lower Cenomanian , Chalk Marl, Cambridge, England, F. Möckler Collection .

Description: Non-brooding autozooids have 14–24 (usually 18–21) mural spines distributed all around the zooidal aperture. These include two distal and two distolateral oral spines that have largest diameters.

Brooding zooids possess 15–20 mural spines. Ovicell roofs were constructed of 11–15 (often 14) spines positioned on the proximal gymnocyst of the distal, brooding autozooid ( Figs 4B- D , 21D , 24P ). The ovicell floor is slightly depressed. Ovicell spine bases are of approximately the same diameter or a little smaller than the proximal mural spine bases, and are markedly smaller than the oral mural spines. They are arranged in a semicircular (horseshoe) pattern on a slight ridge ( Figs 4B- D , 24P ). Median spines are located very close to the mural rim of the distal zooid ( Fig. 4B, C ) where mural spines of this zooid are often absent. However, there is sometimes a distinct intervening area of gymnocyst between the mural rim and the ovicell spine bases ( Fig. 4D ). The two most proximal ovicell spines are located close to the distal boundary wall of the maternal zooid. The distance between adjacent spine bases is approximately equal to their diameter or smaller, although a greater separation is often found in the distal part of the ovicell.

Figures

Figure 4. A, Distelopora langi Ostrovsky & Taylor, fragment of a colony, with two broken ovicells showing ovicell spine bases in a gently curved arch; medial spine bases are adjacent to the proximal edge of the mural rim of the distal zooid. Lower Cenomanian, Cambridge, England, NHM D23111. B-D, Distelopora spinifera Ostrovsky & Taylor; Lower Cenomanian, Cambridge, England. B, part of a colony, showing spine bases of three ovicells; NHM D21651. C, ovicell spine bases arranged in a semicircle, the medial spines adjacent to the proximal edge of the mural rim of the distal zooid; NHM D21667. D, poorly preserved ovicell in which the medial spine bases are some distance from the mural rim of the distal zooid; NHM D21897. Scale bars: A, B = 100 Mm; C, D = 25 Mm.

Figure 21. Schematic diagrams of brood chambers in Tendridae (A, B) and Calloporidae (C-E) in longitudinal and transverse section, showing maternal and distal zooids (fossil spinose ovicells reconstructed). A, Tendra zostericola. B, Heteroecium sp. C, Distelopora bipilata and D. langi. D, Distelopora spinifera, Unidistelopora krauseae. E, Gilbertopora larwoodi.

Figure 24. Schematic diagrams showing the shape of the mural rim and positioning of ovicell spine bases in frontal aspect; number of spines in Stichomicropora is approximate. Note that variable species may appear more than once. A, Stichomicropora sp. 1. B, S. oceani. C, Stichomicropora sp. 6. D, Stichomicropora sp. 1, S. sicksi and S. sulcata. E, S. oceani, Stichomicropora sp. 3, and Stichomicropora sp. 5. F, Stichomicropora sp. 6 and S. baccata. G, Stichomicropora spp. 1, 2 and 4, S. sicksi, S. sulcata, S. erecta, S. biconstricta, S. cf. clathrata and S. punctilla. H, S. marginula, Stichomicropora sp. 3; I, Distelopora bipilata and D. langi. J, Stichomicropora spp. 6 and 7, S. baccata, S. subquadrata, Monoporella spp. 1 and 2, M. prisca, M. nodulifera, and M. exculpta. K, Gilbertopora larwoodi or Wilbertopora mutabilis. L, Distelopora bipilata. M, Monoporella multilamellosa and M.? vincentownensis. N,?Thoracopora sp. and Craticulacella schneemilchae. O, Leptocheilopora tenuilabrosa, Leptocheilopora sp. 1, and Leptocheilopora sp. 2. P, Distelopora spinifera and Unidistelopora krauseae. R, Macropora spp.