Stephanotheca ochracea ( Hincks, 1862 )

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012, A new genus of Lanceoporidae (Bryozoa, Cheilostomata), Zootaxa 3339, pp. 1-29: 17-19

publication ID

10.5281/zenodo.212993

persistent identifier

http://treatment.plazi.org/id/220B4B5A-B071-FFB3-0BA3-27CAFD04FCB3

treatment provided by

Plazi

scientific name

Stephanotheca ochracea ( Hincks, 1862 )
status

n. comb.

Stephanotheca ochracea ( Hincks, 1862)  n. comb.

( Figs 3 View Figure , 36–39 View Figure ; Table 5)

Lepralia ochracea Hincks, 1862: 206  , pl. 12, fig. 3.

Schizoporella auriculata  var. ochracea: Hincks 1880: 260  , pl. 29, fig. 7.

Schizomavella ochracea (Hincks)  : Hayward & Thorpe 1995: 674 (in part: only holotype), pl. 5, figs a, b; Hayward & Ryland 1999: 288, fig. 132 A, C.

Schizomavella rudis ( Manzoni, 1869)  : López de la Cuadra 1991: 232, pl. 27, figs F–H.

Material examined. NMHUK 1899.5.1.977: Schizomavella ochracea  . Holotype. Cornwall.

Description. Colony encrusting, unilaminar, forming a broad spreading sheet. Autozooids in regular series, subrectangular to irregularly polygonal, separated by raised sutures. Frontal shield slightly convex, initially smooth, but soon covered by small rounded nodules; surface evenly perforated by about 45 small, circular pseudopores; marginal pores elongate and more conspicuous in older zooids; periorbital area imperforate and slightly raised. Primary orifice orbicular, slightly longer than wide; anter forming a wide arch projecting distally, with proximolateral edges oblique and rather straight; poster with a wide V-shaped sinus occupying most of the proximal edge; a pair of large, oval condyles with serrate median and proximal edges. Oral spines absent. Avicularia not developed in all autozooids, dimorphic; either small, subrectangular to lanceolate, with complete slender crossbar and oval palatal foramen; or gigantic, subrectangular, occupying almost all the length of the frontal shield, with complete crossbar and variably sized palatal foramen. Both types proximally directed. Ovicell observed once. Globular, prominent, closed by the autozoecial operculum. Exposed ectooecial area circular, with rounded pseudopores larger at the periphery, encircled by a nodular ridge of secondary calcification of the distal zooid. Opening of ovicell wider than long, inclined at an angle, formed by the concave proximal margin of the ooecium, overarching the primary orifice, and extending to its proximolateral corners. Ovicell cleithral. Ancestrula unknown.

Remarks. This species was considered as a variety of S. auriculata  for a long time until Hayward & Thorpe (1995) redescribed the holotype and other material. However, their description needs to be amended; on the one hand, the material used by these authors presents four different morphologies, considered here to belong to four different species ( S. ochracea  , S. barrosoi  , and two new species); on the other hand, the ovicell was not described, which is, however, present in the uncoated portion of the holotype (see Reverter Gil & Fernández Pulpeiro 1995, and fig. 39 in the present paper). The ovicell has also been figured by López de la Cuadra (1991: pl. 27, fig. H, as S. rudis  ) in this case seeming more immersed and exhibiting a nodular crown of secondary calcification that is well developed but interrupted proximally; however, its primary orifice and its avicularia are like the holotype, including the gigantic avicularia.

The shape of the ovicell, its closure, and the shape of the primary orifice and the condyles suggest that S. ochracea  belongs to the genus Stephanotheca  . Yet this species is the only one in the genus exhibiting dimorphic avicularia. The orifice in this species is different from that in S. watersi  , being slightly longer than wide and also exhibiting a more triangular sinus and larger condyles; moreover, the frontal avicularium is larger, more frequent, and placed further away from the orifice. These features bring it closer to S. barrosoi  , which differs from S. ochracea  in the different shape of the orifice and the condyles, in exhibiting vicarious avicularia, and in lacking the frontal gigantic avicularium.

Stephanotheca ochracea  is also the only species of the genus collected in the Atlantic Ocean, specifically southeast of the British Isles and in the Strait of Gibraltar. Its Mediterranean records probably correspond to other species of the genus (see remarks of S. barrosoi  and below).

SD, Standard deviation; N, number of measurements.

TABLE 5. Measurements (in mm) of Stephanotheca ochracea (Hincks, 1862) n. comb. (holotype: NMHUK 1899.5.1.977).

  Mean SD Minimum Maximum N
Autozooid length 0.536 0.0506 0.470 0.632 13
Autozooid width 0.353 0.0558 0.277 0.481 13
Orifice length 0.124 0.0082 0.106 0.134 13
Orifice width 0.119 0.0085 0.105 0.137 13
Adventitious avicularium length 0.096 0.0103 0.079 0.111 9
Adventitious avicularium width 0.058 0.0061 0.047 0.065 9
Gigantic avicularium length 0.351 0.0403 0.288 0.396 5
Gigantic avicularium width 0.162 0.0132 0.144 0.177 5
Ovicell length 0.316 - - - 1
Ovicell width 0.334 - - - 1
Ovicell orifice length 0.128 - - - 1
Ovicell orifice width 0.148 - - - 1
Pseudorous area diameter 0.182 - - - 1

Kingdom

Animalia

Phylum

Bryozoa

Class

Gymnolaemata

Order

Cheilostomatida

Family

Lanceoporidae

Genus

Stephanotheca

Loc

Stephanotheca ochracea ( Hincks, 1862 )

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio 2012

2012
Loc

Schizomavella ochracea

Hayward 1999: 288
Hayward 1995: 674

1995
Loc

Schizomavella rudis (

Cuadra 1991: 232

1991
Loc

Lepralia ochracea

Hincks 1862: 206

Loc

Schizoporella auriculata

Hincks 1880: 260