Therenia David and Pouyet, 1978

Berning, Björn, Tilbrook, Kevin J. & Rosso, Antonietta, 2008, Revision of the north-eastern Atlantic and Mediterranean species of the genera Herentia and Therenia (Bryozoa: Cheilostomata), Journal of Natural History (J. Nat. Hist.) 42 (21 - 22), pp. 1509-1547 : 1526-1527

Genus Therenia David and Pouyet, 1978

Therenia David and Pouyet 1978, p. 169 .

Type species. Hippothoa porosa Smitt, 1873 .

Revised diagnosis

As for Herentia but frontal wall perforated by numerous small pseudopores plus few larger marginal pores; vertical walls with a greater number and generally smaller communication pores; oral spines absent; ovicell largely or completely immersed during later ontogeny, exposed frontal ooecium a variably broad band, generally distinctly narrower than in Herentia , proximal ooecium margins affixed to lateral walls of orifice, aperture more or less parallel to frontal surface; avicularian crossbar asymmetrical, usually twisted along its axis.

Remarks

Therenia was originally introduced as a subgenus of Herentia by David and Pouyet (1978) for species with a pseudoporous frontal wall. Although both were already treated as separate genera in the newly erected family Escharinidae Tilbrook, 2006 , the formal establishment of Therenia to full generic rank remained to be done.

The great similarity in overall morphology suggests that Herentia and Therenia form a monophyletic group within the Escharinidae . Furthermore, the fact that pseudoporous and imperforate lepralioid frontal shields exist in such closely related genera within one family confirms Gordon’s (2000) inference that pseudoporous frontal walls have evolved repeatedly and in different clades (see also Discussion).

An ancestrula was not observed in the present material and there is no information available in the published literature. Moreover, the only colony with the periancestrular area preserved suffered from disturbance and damage during early astogeny ( Therenia peristomata n. sp., Figure 7B ). The budding sequence can, therefore, not be precisely determined, although the overall budding pattern seems to be similar to that of Herentia .

Figures

Figure 7. Therenia peristomata n. sp. Holotype, NHM 2007.10.9.3, off Madeira. (A) General aspect of zooecia at the colony growth margin; (B) early astogenetic zooecia showing a rather flared peristome; note that the ancestrula has been covered by the lowermost zooecia; (C) close-up of autozooecium orifice and avicularium; (D) ovicellate zooecium; note slight differences in condyle morphology to orifice of autozooecium. Scale bars 200 mm (A, B); 50 mm (C, D).