CELLEPOROIDEA Johnston, 1838

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 : 2320-2322

Superfamily CELLEPOROIDEA Johnston, 1838

Family PHIDOLOPORIDAE Gabb and Horn, 1862

Reteporella magellensis (Busk)

( Figure 29A )

Retepora magellensis Busk 1884: 126 , pl. 36, fig. 20

Material

Lectotype (chosen here). BMNH 1887.12 .9.513, Challenger station 320, 37 ◦ 17’ S, 53 ◦ 52’ W, 600 fm (1097 m).

Other material. Hero cruise 731, station 1756, 64 ◦ 47.4’ to 64 ◦ 47.03’ S, 64 ◦ 07.5’ to 64 ◦ 06.2’ W, 91 m, 17 February 1973 (fragments). Hero cruise 715, station 853, 54 ◦ 34’ S, 64 ◦ 20’ W, 91 m, 20 October 1971 (fragments). Eltanin cruise 11, station 974, 53 ◦ 32’ to 53 ◦ 34’ S, 64 ◦ 57’ to 64 ◦ 55’ W, 119–124 m, 12 February 1964 (fragments, including three colony bases).

Description

Lectotype colony incomplete, consisting of a narrow cup, 20 mm high, oval in section with a maximum diameter of 15 mm, about one-third missing; rather thickly calcified, with fenestrulae 1.25–2.5 by c. 1.25 mm. Autozooids in three to eight alternating longitudinal series, broad, convex, with borders distinct only at the growing edge. Frontal shield initially smooth, but thickening and becoming coarsely nodular early in ontogeny; most autozooids with one or two large, marginal areolar pores proximally. Primary orifice transversely oval, almost twice as broad as long, obscured by a deep peristome with thick, slightly flared rim. A single large spine base apparent on each side of the peristome and a thick rimmed, round pseudospiramen medioproximally, adjacent and just proximal to a peristomial avicularium, and linked to the peristome rim by a narrow fissure. Rostrum of peristomial avicularium drop shaped, directed proximo-laterally at an acute angle to frontal plane; crossbar thick, with a stout median columella, lacking a palate. Frontal adventitious avicularia typically numerous, one, two or more per autozooid, with variable position and orientation; dimorphic: one type almost identical to the peristomial avicularium, with denticulate distal rostral rim; second type more elongate oval, with more slender crossbar, and palate with small round foramen. The second type of avicularium also frequent on abfrontal surface of colony. Ovicell prominent, broadest distally, narrowing towards the orifice, with a narrow, elongate and tapered labellum extending in to peristome; frontal calcification smooth, with a longitudinal median fissure extending for the whole frontal surface, closing in later ontogeny to a narrow fissure in the central half of the ovicell’s length; becoming covered by a coarsely nodular ooecial cover, but remaining conspicuous.

Remarks

Busk’s (1884) description of this species is based on the chosen lectotype, from Challenger station 32. A second Challenger collection specimen, from South Africa, attributed to S. magellensis but not listed by Busk does not belong to this species. Busk (1884) noted a specimen from the Falkland Isles in the collection of Miss Gatty, and Waters (1905) reported it from the southern Patagonian Shelf, while López Gappa and Lichtschein (1990) showed it to have an extensive distribution from south of the River Plate to Tierra del Fuego. Its characteristic features are the transversely oval orifice, paired oral spines and thick peristome, with the pseudospiramen situated close to the rim. The granular calcification and oval avicularia can be seen in the figures of López Gappa and Lichtschein (1990), but the distinctive ovicell has not been figured previously.

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).