Reteporella sulcula, 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 : 2322-2323

Reteporella sulcula sp. nov

( Figure 29B, C )

Material

Holotype. NMNH 1154047 : Eltanin cruise 9, station 740, 56 ◦ 06’ to 56 ◦ 07’ S, 66 ◦ 19’ to 66 ◦ 30’ W, 494– 384 m, 18 September 1963; fragment, 30 × 30 mm.

Paratypes. VMNH 013670.00: same data as holotype: numerous fragments, including three recognizable colony bases

Description

Colony architecture unknown, but fragments are mostly flat, suggesting an open, shallow cup without infolded rim. Fenestrulae elongate oval, 2.0–3.25 by 0.5–1.0 mm; trabeculae slender, consisting commonly of three alternating, longitudinal autozooid series, increasing to five at points of trabecular fusion. Autozooids elongate, separated by conspicuous raised sutures; frontal shield flat or gently convex, finely granular, with sparse (four or fewer) marginal pores. Primary orifice wider than long, obscured by a deep peristome with a medio-proximal fissure running from a peaked rim to an oval pseudospiramen, the distance between it and the peristome rim equivalent to one-quarter total frontal length of autozooid; two pairs of lateral spines present on peristome rim. Frontal adventitious avicularia present, typically one per autozooid, median in position, directed proximally or proximo-laterally; rostrum slightly acute to frontal plane, drop shaped, with complete crossbar and stout columella above a small palatal foramen. Vicarious avicularia sparse, in proximal axils of fenestrulae, 0.35 mm long, with swollen cystid; rostrum broadly oval, distal rim straight and bicusped, crossbar complete, with stout columella above a minimal palatal foramen. Ovicell broader than long, smooth surfaced, with very small, inconspicuous frontal foramen; labellum narrowly tapered to a rounded edge, with a broad fissure on each side.

Etymology

Latin, sulcus: grooved, with reference to the sutures bordering the frontal shields of the autozooids.

Remarks

Species of Phidoloporidae are distributed in shelf seas worldwide, and among them Reteporella is possibly the most widespread genus, with numerous species described from polar, temperate and tropical environments. Phidoloporids are morphologically complex, and before the broad application of SEM methods descriptions were incomplete and often misleading, with much resulting taxonomic confusion. North Atlantic species of Reteporella are adequately described ( Hayward and Ryland, 1999), numerous species from the tropical southwest Pacific have been described and illustrated by SEM (Hayward, 1999, 2000, 2004), as have all species presently known from Antarctica ( Hayward, 1995), but for much of the marine realm Reteporella species have yet to be adequately described or figured. López Gappa (1978) listed just three taxa attributed to Reteporella (as Sertella ) from the Argentinian Patagonian Shelf, including Reteporella magellensis (above), yet it is probable that the diversity of the genus in this region is at least as great as in the Antarctic. Reteporella sulcula sp. nov. is a distinctive species, especially characterized by its elongate, symmetrically oriented labial fissure, connecting the pseudospiramen to the peristome rim, its four oral spines and the large, axial vicarious avicularia, with broad, straight distal edge. The ovicell is also characteristic, being broad and short, with only a transient median foramen, and a pronounced labellum

Figures

Figure 29. (A) Reteporella magellensis, Eltanin 11. Ovicelled zooids, characteristic peristome, avicularia and frontal shield calcification well shown. (B,C) Reteporella sulcula sp. nov., Paratype. (B) Autozooids and an ovicelled zooid, with characteristic avicularia and long peristomial fissure; (C) autozooids and ovicelled zooids, with large, infrafenestrular avicularium. Scale bars: 0.25 mm (A, C), 0.2 mm (B).