Stephanotheca ochracea

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012, A new genus of Lanceoporidae (Bryozoa, Cheilostomata), Zootaxa 3339, pp. 1-29: 16-17

publication ID 10.5281/zenodo.212993

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scientific name

Stephanotheca ochracea


The Stephanotheca ochracea  group of species

In their redescription of S. ochracea, Hayward & Thorpe (1995)  studied its holotype from the Atlantic Ocean, as well as other material from the Mediterranean Sea that they placed in the same species. In our opinion, the original samples actually include four different morphologies, only two of which are correctly shown in their paper; moreover, the ovicell was not described, despite being present in four of the colonies, including the holotype of the species.

However, this is just a part of the problem. We have also revised material originally identified as S. monoecensis  and S. arrogata  , including the types of both species. We verified that the primary orifice in all these specimens is especially alike, exhibiting certain within-colony variations in size, outline, arching of the distal rim, width and inclination of the sinus, and, less importantly, condyle size. These subtle variations are also remarkable between colonies with different morphologies, but hardly seen without SEM; therefore, studying the primary orifice by light microscopy is insufficient to discriminate among the different species in this group. However, the variations in orificial morphology and size are clearly correlated with variations in other features, particularly the size, frequency and position of the suboral avicularium, as well as the frequency of the pseudopores in the frontal shield. The ovicell, although not always present in the available material, is another feature that shows considerable variation. These features, easily seen by light microscopy, vary in a discontinuous way in different colonies, allowing the discrimination of different morphological groups.

To sum up, in spite of the difficulty (near impossibility without SEM) of establishing groups amongst all this material by focusing exclusively on the primary orifice, we believe the other morphological features allow clear differentiation of different morphological types. We recognize an S. ochracea  group of species that presently includes Lepralia ochracea Hincks, 1862  , Schizoporella ambita  var. monoecensis Calvet, 1927  , Lepralia arrogata Waters, 1879  and two species described here from material previously identified as Schizomavella ochracea  .

All of the species in this group clearly differ from S. barrosoi  and S. watersi  in the shape of the orifice and other features, which will be discussed in each case.