Cellarinella diatriaria, 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 : 2298-2299

Cellarinella diatriaria sp. nov.

( Figure 18C, D )

Material

Holotype. NMNH 1154034 : Eltanin cruise 12, station 1078, 61 ◦ 27’ to 61 ◦ 26’ S, 67 ◦ 19’ to 67 ◦ 24’ W, 604 m, 12 April 1964; almost complete colony, 23.75 mm long, with maximum width 3.75 mm; ancestrula and first two/three (?) astogenetic generations missing, but rhizoids present.

Paratypes. VMNH 013677.00: same data as holotype; 10 fragments, largest 25 mm long, representing at least four further colonies .

Description

Colony erect, sparsely branched, the branches flat, or indistinctly curved, with a thick, oval section; regular transverse constrictions, interpreted as growth checks, occur every four to seven autozooid generations, imparting a distinctly nodular appearance. Autozooids in regular, alternating whorls of up to 14, strongly convex, the boundaries of each indicated by gullies, but without clear sutures between adjacent frontal shields; frontal surface of colony a single, smoothly calcified layer densely perforated by small round pores developed from the original marginal pores. Secondary orifice about as wide as long, the proximal and lateral borders defined by a smooth, slightly flared lip enclosed within a thickened, frontally projecting proximal peristome; distal border straight or slightly concave. Almost all autozooids with an adventitious avicularium in each proximo-lateral corner of the peristome, with a short, triangular, distally hooked rostrum, acute to frontal plane and directed disto-laterally; crossbar thick but without a columella. Ovicells not observed.

Measurements

Secondary orifice, length 0.23 ± 0.01 mm (n = 15, mean ± SD); secondary orifice, width 0.23 ± 0.08 mm (n = 15, mean ± SD).

Etymology

Greek, dis: two; Latin: atriarius: doorkeeper, alluding to the paired peristomial avicularia.

Remarks

In its narrow, nodulated branches and paired peristomial avicularia C. diatriaria is reminiscent of the Antarctic species C. njegovanae Rogick, 1956 . However, in that species the secondary orifice is twice as wide as long, with a complete inner lip, and the distal edge of the peristome overarches the proximal edge and partially obscures the avicularia. Cellarinella seemed to be essentially an endemic Antarctic genus, with only one species, C. dubia Waters, 1904 , being primarily subantarctic in distribution. However, the description here of two new species from the subantarctic southwest Atlantic challenges that supposition.

Figures

Figure 18. (A, B) Cellarinella incompta sp.nov., Paratype. (A) Portion of colony; (B) detail to show two secondary orifices and an avicularium. (C,D) Cellarinella diatriaria, Paratype. (C) Secondary orifices and paired avicularia of two autozooids; (D) growing edge of branch. Scale bars: 0.5 mm (A), 0.25 mm (B, C, D).