Calloporidae NORMAN 1903
Creators: name: Ostrovsky, Andrew N.
name: Taylor, Paul D.
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Bryozoa
Gymnolaemata
Cheilostomatida
Calloporidae

description: FAMILY CALLOPORIDAE NORMAN, 1903   Remarks: Spinose ovicells were first described by Ostrovsky & Taylor (2004) in three Cretaceous calloporid genera. Here we present a more detailed description of the structure of their ovicells.   
 GENUS DISTELOPORA LANG, 1915 DISTELOPORA BIPILATA LANG, 1915   
(FIGS 3A- D, 21C, 24I, L)  
 Material: NHM D21876, D21879 -21883, D23019, Cretaceous, Lower Cenomanian, 10 ft (3.05 m) from the base of the Chalk Marl, Cambridge, England, F. Möckler Collection. NHM BZ4958, Lower Cenomanian (? carcitanense Subzone), Porcellaneous Beds (= Chalk Marl), Barrington Chalk Pit, Cambridgeshire, England, A. N. Ostrovsky & P. D. Taylor Collection.   
 Description: Non-brooding autozooids (i.e. those that have no brood chamber on their proximal gymnocyst) possess 6–8 mural spine bases that indent the mural rim. These are usually paired, with the most proximal pair having the largest diameter and the distalmost pair (the oral spine bases) the smallest. The proximal part of the mural rim is usually devoid of spines (Fig. 3A).   
Brooding autozooids positioned distally of maternal (egg-producing) zooids usually have six, sometimes seven, mural spine bases plus an additional 5–10 (usually 6–7) spines that constructed the ovicell. As with the mural spines, only the bases of the ovicell spines are preserved, the spines themselves always being broken off at their basal articulations and lost in these fossils. Ovicell spine bases are aligned in a distally convex arch on the proximal gymnocyst of the distal (brooding) autozooid (Figs 3A- D, 24I, L). This arch is normally gently curved (Figs 3A, C, D, 24I), but is occasionally more convex (Fig. 3B, left ovicell), and a near semicircle of spine bases was found in one example (Fig. 3B, right ovicell, 24 L). As a rule, the median ovicell spine bases are adjacent to the proximal edge of the mural rim of the distal zooid, and may slightly indent it (Fig. 3D). However, they can be also be positioned further from the mural rim (Fig. 3C). The outermost spine bases are always well-separated from the distal edge of the maternal zooid. The distance between adjacent ovicell spine bases is equal to or greater than their diameters. They have either approximately the same diameter as the most distal oral spines or are smaller. The floor of the ovicell, formed by the proximal gymnocyst of the distal zooid, is slightly concave.  
 DISTELOPORA LANGI OSTROVSKY & TAYLOR, 2004   
(FIGS 4A, 21C, 24I)  
 Material: NHM D21873-21875, D21878, D23059, D23111, BZ4961, BZ4962, Cretaceous, Lower Cenomanian, 10 ft (3.05 m) from the base of the Chalk Marl, Cambridge, England, F. Möckler Collection.   
 Description: Non-brooding autozooids possess 9–11 (up to 16) mural spine bases, including usually four oral mural spines, though as many as six can be present. Proximal spine bases are typically slightly larger than distal spine bases. However, this character varies, and the largest spine bases can be any except for the most distal.   
There are 10–12 mural spines in brooding (ooeciumbearing) zooids. Ovicell roofs were constructed of 7–8 spines borne on the proximal gymnocyst of the distal zooid (Figs 4A, 21C, 24I). The bases of these articulated spines typically have the same diameter as distal oral spines but can be somewhat smaller or larger. They are arranged in a gently curved, distally convex arch. The median spines are normally adjacent to the proximal edge of the mural rim of the distal zooid (Fig. 4A) but are sometimes separated from it by a narrow strip of gymnocyst. The outermost spine bases are always located far from the distal edge of the maternal zooid, and the distance between neighbouring ovicell spine bases is equal to or smaller than their diameter. The ovicell floor is slightly concave.
description: Published as part of Ostrovsky, Andrew N. & Taylor, Paul D., 2005, Brood chambers constructed from spines in fossil and Recent cheilostome bryozoans, pp. 317-361 in Zoological Journal of the Linnean Society 144 (3) on pages 322-323, DOI: 10.1111/j.1096-3642.2005.00179.x, http://zenodo.org/record/5434718