Therenia porosa ( Smitt, 1873 ) Berning & Tilbrook & Rosso, 2008

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 : 1527-1528

Therenia porosa ( Smitt, 1873) , new combination

Hippothoa porosa Smitt 1873, p. 41 , Plate 7, Figure 158.

Escharina porosa: Winston 1986, p. 19 , Figure 39; Winston 2005, p. 83, Figures 227– 230.

Non Escharina porosa Verrill 1879 (see Maturo and Schopf 1968, p. 48).

Non Escharina porosa: Cook 1985, p. 165 , Plate 16, Figures E, F; Hayward 1974, p. 377, Figure 4A, B ; Rosso 1996a, Plate 4, Figure f.

Remarks

Original material of T. porosa from the type location off Florida was recently redescribed and illustrated by Winston (2005); therefore, this needs not to be repeated here. Density of frontal wall pores is here estimated based on her Figure 227 [ PD 9 ¡1, 7–11 (1, 7)] .

Winston noted that the Mediterranean and eastern Atlantic specimens, which were referred to this species by Hayward (1974) and Cook (1985), respectively, are distinct from the one described by Smitt (1873). This view is corroborated here and the differences between T. porosa and the Old World species, introduced as T. rosei n. sp. and T. cryptooecium n. sp., respectively, are demonstrated in detail below. The geographic range of distribution of T. porosa is therefore restricted to the westernmost Atlantic (Florida, Jamaica), although Winston (2005) stated that the specimens illustrated by Osburn (1952) and Banta and Carson (1977) from the Pacific coasts of Central America are very similar. However, this statement needs to be verified using SEM as interspecific differences may be extremely subtle. Although much more likely to be conspecific, even the specimens reported by Canu and Bassler (1928a, p. 134, Figure 29; Plate 19, Figures 8 , 9) from the Gulf of Mexico and other western Atlantic regions cannot be regarded as a synonym without having seen the original material. Their description is somewhat contradicting that of Winston (2005), e.g. regarding mandible length, and the avicularium seems to be situated more closely to the orifice rim. Another record of T. porosa that needs to be confirmed is from the Netherlands Antilles in the southern Caribbean ( Kobluk et al. 1988, p. 429). The species from Brazil identified as Mastigophora porosa by Marcus (1955, p. 299, Plate 5, Figures 58–61) is clearly distinct owing to a much wider sinus and different condyles. Whether Marcus’ specimens are conspecific with the Brazilian material described by Canu and Bassler (1928b, p. 38, Plate 9, Figure 10) under the same name cannot be pursued from their description and illustration.

According to Winston (2005), T. porosa encrusts corals, shells and coralline algae, and is common in cryptic reef environments. Although colony size was generally small, the zooids were heavily bored and grazed, and few ovicellate zooecia were present.

Figures

Figure 4. Herentia thalassae David and Pouyet, 1978. MNHN 7619, off NW Spain; note that the vertical component in these perpendicular views is greatly understated, the distal parts of the zooecia and ooecia are distinctly raised. (A) General aspect of colony; (B) close-up of ovicellate zooecium; (C) close-up of autozooecium. Scale bars: 400 mm (A); 100 mm (B, C).

Figure 8. Geographic distribution of Herentia and Therenia species in the North Atlantic and Mediterranean Sea. Note the co-occurrence of three species (H. hyndmanni, H. andreasi n. sp. and T. peristomata n. sp.) at Madeira, and the wide range of H. hyndmanni.