Conescharellina pustulosa, Bock & Cook, 2004

Bock, Philip E. & Cook, Patricia L., 2004, A review of Australian Conescharellinidae (Bryozoa: Cheilostomata), Memoirs of Museum Victoria 61 (2), pp. 135-182 : 158-159

Conescharellina pustulosa sp. nov.

Figures 12A–D

Holotype. NMV F99000 , stn SLOPE-2.

Paratypes. NMV F99001 , stn SLOPE-2 (9 colonies) .

Other specimens. NMV F99002, unlabelled Maplestone specimens, probably from NSW (5 colonies); NMV F101961, stn BSS-158 (1 colony); NMV F101962, stn BSS-169 (1 colony); NMV F101963, stn SLOPE-40 (14 colonies); NMV F101964, stn SLOPE-45 (1 colony); NMV F101965, stn GAB-049 (1 colony).

Etymology. pustula (L) - a bubble or blister, with reference to the calcification of the zooid surfaces.

Diagnosis. Conescharellina with small, domed colonies. Zooids orifices with a subtriangular sinus; surrounded by raised, pustular secondary calcification, that also covers the antapical surface. Avicularia antapical, peristomial, raised, bar without a ligula.

Description. Colonies small, domed. Surface irregular, formed by raised, pustular secondary calcification. Zooids in quincuncial series, peristomes raised laterally, prominent only at colony margins. Primary orifice with a wide subtriangular sinus and minute condyles. Adapical pore outside the peristome rim. One small peristomial avicularium lateral and antapical, nearly vertical to the rim of the peristome, rostrum rounded, bar without a ligula; other occasional avicularia scattered among the zooids. Adapical region with a few, lunate root pores; antapical region with more pustular secondary calcification, cancelli and avicularia.

Colony diameter 2.2 mm, height 1.2 mm, number of whorls 6, number of zooids per whorl 8.

Remarks. The pustular calcification occurs among the zooid orifices and is a prominent feature of the antapical surface of the small colonies. The only other species in the samples examined that possesses an antapical peristomial avicularium is C. obscura , but this is not placed on the edge of the peristome as in C. pustulosa . C. pustulosa bears a close but superficial similarity to C. papulifera Harmer (1957: 734 , pl. 47 figs 7–9, text-fig. 70C). Harmer did not describe or figure the primary orifice, that he was not certain was visible. He mentioned paired avicularia and radially costulate zooid orifices but did not figure them. Specimens of C. papulifera (BMNH, 1964.3.2.3, paratype?, Java Sea and 1964.3.2.2, Siboga stn 77, Borneo Bank, 59 m) have been examined. They are minute; their dimensions being less than half of those of C. pustulosa at the same astogenetic stage. The peristomes are raised and tubular, arranged in radial series; the primary orifices are not visible. Minute avicularia alternate with the zooid orifices and none are antapical and peristomial.

C. pustulosa is distributed from the coasts of New South Wales to Bass Strait and the Great Australian Bight , from a wide depth range of 36 to 800 m. There is, however, little variation in the characters of the colonies from the different populations .

Figures

Figure 12. Conescharellina pustulosa sp. nov. A–B, NMV F99000, holotype. A, adapical view of colony, scale = 500 µm. B, detail of two marginal orifices, showing thick secondary calcification and peristomial avicularia, scale = 200 µm. C, NMV F99001, paratype, group of orifices, adapical pores with developing ectooecial lamina arrowed, scale = 200 µm. D, NMV F99002, colony lateral view, growth direction (antapical) arrowed, scale = 500 µm.