Reteporella tortuosa, Hayward & Winston, 2011

Hayward, Peter J. & Winston, Judith E., 2011, Bryozoa collected by the United States Antarctic Research Program: new taxa and new records, Journal of Natural History 45 (37 - 38), pp. 2259-2338 : 2323-2325

Reteporella tortuosa sp. nov.

( Figure 30 )

Material

Holotype. Holotype 1154048: Eltanin cruise 9, station 740, 56 ◦ 06’ to 56 ◦ 07’ S, 66 ◦ 19’ to 66 ◦ 30’ W, 494– 384 m, 18 September 1963; one large fragment.

Paratypes. VMNH 013671.00: same data as holotype; number of fragments, perhaps part of the holotype colony .

Description

Colony architecture unknown; largest fragment (holotype) 15 × 20 cm, irregularly curved and twisted, apparently representing anastomosed edges of two lobes of the same colony. Fenestrulae elongate, irregular, 2.5–4.0 by 1.0–2.0 mm; trabeculae consist of two to four alternating, longitudinal autozooid series. Autozooids appearing irregularly polygonal, with boundaries marked by distinct, raised sutures. Primary orifice longer than wide, with straight proximal edge; oral spines lacking. Peristome short, not projecting; with a small oval avicularium on one side, abutting against a lobe projecting from the other side, defining a large, round pseudospiramen, linked to the proximal peristome rim by a distinct, short suture. Frontal shield uneven, often concave centrally, coarsely granular, with four, six or more conspicuous, large and irregularly shaped marginal pores. Frontal avicularia frequent, variably positioned and orientated; rostrum broadly oval, crossbar complete. Additional, large adventitious avicularia present on many autozooids, with tumid cystid occupying much of frontal shield; rostrum c. 0.3 mm long, directed obliquely proximally, laterally biconcave with flared tip, crossbar thick, with a stout cylindrical columella occupying much of the palatal foramen. Ovicell short and broad, with wide, straight-edged labellum; submerged, covered by granular ooecial cover and inconspicuous, generally recognized only by its persistent frontal fissure. Abfrontal surface with numerous small oval avicularia, identical to frontal type.

Etymology

Latin, tortuosus: twisted, with reference to the shape of the colony fragments.

Remarks

The coarsely granular calcification of R. tortuosa sp. nov. recalls that of R. magellensis , which also displays small, oval adventitious avicularia superficially similar to those seen in the new species. However, the peristome of R. tortuosa distinguishes it immediately from R. magellensis , with its pseudospiramen situated close to the peristome rim, just below a small suboral avicularium with oval rostrum. In the latter the pseudospiramen is distant from the peristome rim, and connected to it by a long groove, and the suboral avicularium is larger, with a drop-shaped rostrum. The ovicell of R. magellensis is elongate oval, with a conspicuous longitudinal foramen, and a pronounced, straight-edged labellum, whereas that of R. tortuosa is short and broad, and the short labellum has a rounded edge.

Figures

Figure 30. Reteporella tortuosa sp. nov., Paratype. (A) Group of autozoooids, with large dimorphic avicularium; (B) detail to show frontal surface of ovicell and peristomial avicularium. Scale bars: 0.25 mm (A), 0.15 mm (B).