Kamchatkapora, Taylor & 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 : 1920

Genus Kamchatkapora gen. n.

Type species

Kamchatkapora o zhgibesovi sp. n.

Etymology

In reference to the type locality off the Kamchatka Peninsula .

Diagnosis

Colony massive, probably hemispherical when complete, multilamellar, each layer formed of numerous cup-shaped subcolonies overarching earlier layers joined at their outer edges; autozooids free-walled, apertures clustered into small groups often elongated radially from subcolony centres, minimally differentiated from kenozooids but very slightly larger and with walls prolonged into low spines at aperture corners; kenozooids free-walled, more numerous than autozooids, occupying centres of subcolonies and surrounding autozooids elsewhere; gonozooids fixed-walled, the densely pseudoporous roof sutured, lobate, surrounding autozooid clusters, the lobes extending between autozooid clusters, ooeciopore elliptical.

Remarks

Among existing stratocormidial cyclostome genera, Kamchatkapora resembles Multifascigera d’Orbigny, 1853 in having autozooidal apertures grouped into clusters that usually radiate from the centres of the subcolonies. However, in Multifascigera the clusters are fascicles bounded by exterior wall calcification, lacking in Kamchatkapora , and the colony surface between clusters is formed of exterior wall and not open kenozooids as in Kamchatkapora . The new genus also shows similarities to Semimulticavea d’Orbigny, 1853 with respect to the fixed-walled gonozooids and free-walled autozooids and kenozooids, as well as the general growth pattern. However, autozooidal apertures are arranged in well-defined uniserial rows in Semimulticavea , unlike the irregular clusters seen in Kamchatkapora . Further comparisons with established stratocormidial cyclostomes can be found in the Discussion section below.

Among extant cyclostome genera, the fixed-walled gonozooids and free-walled autozooids and kenozooids of Kamchatkapora together with the overall lamellar colony-form prompts comparison with the extant genus Favosipora MacGillivray, 1885 , which was revised by Gordon and Taylor (2001). Despite sometimes forming multilamellar colonies, as in F. ainui Taylor and Grischenko, 2015 from northern Japan, Favosipora is not known to construct large and massive colonies, nor does it possess well-defined subcolonies on the same plane (cf. the vertically staked subcolonies of F. bathyalis Gordon and Taylor, 2010 ).

The similarity in skeletal organisation and configuration of the autozooids and gonozooids suggests a close relationship between Kamchatkapora and Favosipora notwithstanding the stratocormidial colony-form of Kamchatkapora . For this reason, Kamchatkapora is provisionally assigned to the same family – Densiporidae – as Favosipora until molecular data allows its affinities to be more firmly established. The fusiform colonies of Densipora , the type genus of Densiporidae , have screw-like ridges on their surface and the autozooidal apertures are surrounded by about 6–9 rounded spines processes ( Bock et al. 2018), neither feature apparent in Kamchatkopora.