Stephanotheca perforata , Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012
treatment provided by
Stephanotheca perforata n. sp.
( Figs 57–61View FIGURES 57 – 61; Table 8)
Schizomavella ochracea (Hincks) : Hayward & Thorpe 1995: 674 (part).
Etymology. The name refers to the closely dispersed perforations in the frontal shield of the autozooids.
Description. Colony encrusting, unilaminar, forming broad sheets. Autozooids in regular series, irregularly polygonal, relatively broad, separated by raised sutures. Frontal shield rather flat, rough, evenly perforated by about 75 small, circular pseudopores; periorbital area imperforate and slightly raised; marginal pores elongate and more conspicuous in older zooids. Primary orifice orbicular, similar to that of S. ochracea but larger and with a Ushaped sinus; condyles large, denticulate only in proximal half. Oral spines absent. Suboral avicularia sporadic, frequently wanting; small, oval, sometimes slightly displaced to one side; proximally directed. Complete ovicell observed once; this globular, prominent, with a large convex pseudoporous area of ectooecium, surrounded by low nodular rim of secondary calcification, incomplete proximally. Orifice in ovicellate zooids dimorphic, with a smaller sinus; ovicell opening inclined at an angle, closed by operculum. Ancestrula unknown.
SD, Standard deviation; N, number of measurements.
Remarks. As with the previous species, the material here ascribed to S. perforata n. sp. has previously been cited by Hayward & Thorpe (1995) as Schizomavella ochracea . In fact, its primary orifice is similar to S. ochracea but it is much larger and usually has a more rounded sinus. The autozooids are clearly wider and flatter and are perforated by a significantly larger number of pseudopores (75 instead of 45). The suboral avicularium is smaller, usually absent, clearly oval (never rectangular), and gigantic avicularia are lacking.
We have only studied one complete ovicell of S. perforata n. sp., therefore its morphological variability is unknown. It seems to differ from the other species of the genus by exhibiting a clearly convex, extensive pseudoporous area, without a defined nodular crown of secondary calcification. It is basically prominent, not subimmersed, recumbent on the surface of the distal zooid ( Fig. 60View FIGURES 57 – 61). The orifice of the only ovicellate zooid is dimorphic. In the dried specimen it is not closed by the operculum, which is in the lower position where it seals the primary orifice. Nevertheless we infer that the ovicell in this species is probably cleithral as in other of the genus.
Stephanotheca perforata n. sp. is known from only two colonies collected from the Mediterranean Sea, one of them from the Spanish coast, but no other details of locality are provided.
|Adventitious avicularium length||0.061||0.0064||0.055||0.074||9|
|Adventitious avicularium width||0.047||0.0036||0.042||0.052||9|
|Ovicell orifice length||0.150||-||-||-||1|
|Ovicell orifice width||0.154||-||-||-||1|
|Pseudorous area length||0.247||-||-||-||1|
|Pseudorous area width||0.267||-||-||-||1|
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