Kamchatkapora ozhgibesovi Taylor and Grischenko 2024, sp. n.
Creators: name: Taylor, Paul D.
name: Grischenko, Andrei V.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Bryozoa
Stenolaemata
Cyclostomatida
Densiporidae
Kamchatkapora
Kamchatkapora ozhgibesovi

description: Kamchatkapora ozhgibesovi Taylor and Grischenko sp. n.
(Figures 2–5)
Type material
Holotype: NHMUK 2017.7.11.2 (Figure 2 (C,D)), Station 190, Sea of Okhotsk, shelf off western Kamchatka Peninsula, 56°51'1''N, 154°52'0''E, 114.5 m depth, dredged using a beam trawl from RV Professor Probatov, 6 August 2013, collected by T.B. Morozov. Paratypes: NHMUK 2017.7.11.3 (Figure 2 (E,F)), 2017.7.11.4 (Figure 2 (A,B)); ZIRAS 1 / 53,003, 13 colony fragments.
Etymology
Honorific for Prof. Dr Vladimir P. Ozhgibesov, Head of Regional and Oil Geology Department (1992–2003) of the Perm State National Research University, Perm, Russia, in recognition of his contribution to the knowledge of Permian bryozoans of Pre-Urals.
Description
Colony massive, largest fragment measuring 5.5 cm high by 7 cm wide and having 19 layers (Figure 2 (D)), colonies probably hemispherical when complete; multilamellar, each layer formed of numerous cup-shaped subcolonies overarching earlier layers, vertical distance between layers averaging 2.42 mm (range 1.92–3.0 mm, SD 0.39 mm, N = 10); subcolonies either fused at their outer edges to form compound structures of 2–8 subcolonies (Figure 3), or irregularly abutting one another; fractured specimens reveal vertical stacks of subcolonies, each new subcolony generally positioned directly over the centre of a subcolony in the underlying layer (Figure 2 (D)). New subcolonies apparently originate through upward growth of kenozooids at subcolony centres and between clusters of autozooids; subcolony undersides formed on basal exterior walls, slightly rugose transversely to growth direction, lacking pseudopores. Colony surface covered in hummocks (monticules) centred on the subcolonies. Early astogeny unknown. Subcolonies circular to elliptical in surface view, averaging 6.6 mm (range 5.0– 9.7 mm, SD 1.5 mm, N = 10) in maximum width by 4.8 mm (range 3.8–7.0 mm, SD 1.0 mm, N = 10) in minimum width; central, autozooid-bearing area of subcolonies averaging 3.9 mm (range 2.8–5.4 mm, SD 0.9 mm, N = 10) in maximum width by 3.2 mm (range 2.4–4.3 mm, SD 0.5 mm, N = 10).
Autozooids free-walled, apertures rounded polygonal, clustered into small groups often elongated radially from subcolony centres (Figure 4 (B)), minimally differentiated from kenozooids but very slightly larger and with walls prolonged into low spines 20– 30 µm high at aperture corners (Figure 4 (C)). Aperture minimum diameter averaging 162 µm (range 143–202 µm, SD 19.8 µm, N = 10).
Kenozooids free-walled, more numerous than autozooids, occupying centres and peripheries of subcolonies and surrounding autozooids elsewhere (Figure 3 (A)); of similar size to autozooids but more variable; apertures rarely closed by a diaphragm, rounded polygonal, minimum diameter averaging 134 µm (range 66–192 µm, SD 36.7 µm, N = 10).
Gonozooids fixed-walled (Figure 5 (A,D)), the densely pseudoporous roof sutured (Figure 5 (C)), lobate, surrounding autozooid clusters, the lobes spreading out between autozooid clusters, measuring about 1.5–2.5 mm in maximum width by 0.9–2.0 mm in minimum width. Ooeciopore elliptical, 242 µm by 11 µm in single measured example, collapsed slightly inwards of the brood chamber roof (Figure 5 (B)). Oeciostome short, funnel-shaped.
Interior walls close to apertures exhibiting a distally foliated ultrastructural fabric (Figure 4 (D)), the tabular fibrous crystallites averaging in width 3.69 µm (range 1.17– 6.98 µm, SD 1.8 µm, N = 10), pierced by irregularly spaced interzooidal pores. Mural spines (Figure 4 (E,F)) developed widely on surfaces of interior walls, length averaging 18.1 µm (range 11.3–27.1 µm, SD 4.2 µm, N = 10), shaft moderately straight, ending in a head 10– 16 µm in diameter bearing spike-like spinelets each up to 5 µm in length. Exterior wall roofing gonozooids with circular or elliptical (Figure 5 (C)), diameter averaging 4.04 µm (range 3.01–4.99 µm, SD 0.53 µm, N = 10), average centre-to-centre spacing 10.26 µm (range 8.79–12.11 µm, SD 1.09 µm, N = 10).
Remarks
All of the material available is fragmentary. Some of the fragments fit together and it is thought likely that all are pieces of a single large colony broken up during trawling. If so, the intact colony may have been more than 15 cm across.
Details of the growth pattern and zooidal budding in Kamchatkapora await study using serial thin sectioning or, preferably, Computerised Tomographic (CT) scanning (see Key and Wyse Jackson 2022 for a review of this application in bryozoology). Preliminary observations suggest that new subcolonies were generated mostly by upward growth from groups of kenozooids at the centres of earlier subcolonies. Intrazooidal fission like that described from some other stratocormidial cyclostomes (eg Hillmer et al. 1975) has not been observed and may not play a role in the formation of new subcolonies.
Distribution
Sea of Okhotsk, off Kamchatka, north-eastern Pacific.
description: Published as part of Taylor, Paul D. & Grischenko, Andrei V., 2024, A new bryozoan genus from the Sea of Okhotsk and the taxonomy and geological history of ' stratocormidial' cyclostome bryozoans, pp. 1917-1935 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 58 (41 - 44) on pages 1922-1925, DOI: 10.1080/00222933.2024.2396995, http://zenodo.org/record/14241465