Kamchatkapora ozhgibesovi Taylor and Grischenko, 2024

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, Journal of Natural History (J. Nat. Hist.) 58 (41 - 44), pp. 1917-1935 : 1922-1925

publication ID	https://doi.org/ 10.1080/00222933.2024.2396995
persistent identifier	https://treatment.plazi.org/id/3B6987A0-FFB9-8063-FE91-FB75FD7FF9CE
treatment provided by	Plazi
scientific name	Kamchatkapora ozhgibesovi Taylor and Grischenko
status	sp. nov.

Treatment

Kamchatkapora ozhgibesovi Taylor and Grischenko sp. n.

( Figures 2–5 View Figure 2 View Figure 3 View Figure 4 View Figure 5 )

Type material

Holotype: NHMUK 2017.7 About NHMUK .11.2 ( Figure 2 View 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 GoogleMaps . Paratypes: NHMUK 2017.7 About NHMUK .11.3 ( Figure 2 View Figure 2 (E,F)), 2017.7. 11.4 ( Figure 2 View 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 View 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 View 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 View 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 View 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 View 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 View 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 View Figure 5 (A,D)), the densely pseudoporous roof sutured ( Figure 5 View 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 View Figure 5 (B)). Oeciostome short, funnel-shaped.

Interior walls close to apertures exhibiting a distally foliated ultrastructural fabric ( Figure 4 View 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 View 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 View 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 .