Brood chambers constructed from spines in fossil and Recent cheilostome bryozoans Author Ostrovsky, Andrew N. Author Taylor, Paul D. text Zoological Journal of the Linnean Society 2005 2005-07-31 144 3 317 361 https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2005.00179.x journal article 10.1111/j.1096-3642.2005.00179.x 0024-4082 5434718 UNIDISTELOPORA KRAUSEAE (VOIGT & SCHNEEMILCH, 1986) ( FIGS 5A, B , 21D , 24P ) Material: VC 11025, Cretaceous, Lower Campanian , Grube Allemania, Höver, near Hannover, Germany . VC T 10580, Lower Campanian , Grube Alsen , Lägerdorf , near Hamburg , Germany . VC T 10581, Lower Campanian , Grube Breitenburg , Germany . Description: Non-brooding zooids of this uniserial species have 24–25 mural spine bases, compared with 20– 21 in ovicellate zooids. Distal spine bases, particularly the four ‘oral’ spine bases, are slightly larger than the others. Ovicell roofs were constructed of 18–19 spines whose bases are arranged atop a low semicircular ridge and raised above the concave ovicell floor formed by the proximal gymnocyst of the distal brooding zooid ( Figs 5A, B , 21D , 24P ). The diameter of ovicell spine bases is markedly smaller than that of mural spine bases, especially the nearby oral spine bases of the maternal zooid. In all cases observed, the distal, median ovicell spine bases are located on the mural rim of the distal zooid where mural spines were absent. The two most proximal spine bases are placed very close to the distal edge of the maternal zooid. Ovicell spine bases are closely spaced, with the distance between adjacent bases usually less than spine base diameter, except in the distal part of the ovicell where the spine bases are sparser and spaced further apart. Remarks: All spines in the species of Distelopora and Unidistelopora described above were basally articulated, as indicated by the double ring structure seen in some of the spine bases ( Figs 4C , 5B ; Ostrovsky & Taylor, 2004 ). This is also supported by the fact that no spines are preserved in situ. In the majority of the ovicellate zooids of Distelopora spp. and Unidistelopora krauseae , the proximal part of the mural rim of the distal zooid lacks mural spines in the zone where ovicell spine bases adjoin it. Thus, the mural spine bases and distalmost, median ovicell spine bases often (always in the case of U. krauseae ) form a continuous line, and the distalmost ovicell spine bases are positioned where the most proximal mural spine bases are normally located in the nonbrooding zooids ( Figs 4A, C , 5A, B , 24P ). However, the ‘missing’ proximal mural spines do develop when the ovicell spine bases are separated from the mural rim, and also in intramural reparative buds formed within the distal zooid.