Cornucopina bryonyae, Branch & Hayward, 2005

Branch, M. L. & Hayward, P. J., 2005, New species of cheilostomatous Bryozoa from subantarctic Marion and Prince Edward Islands, Journal of Natural History 39 (29), pp. 2671-2704 : 2679-2680

Cornucopina bryonyae sp. nov.

( Figure 4C )

Material

Holotype: St. 42 Marion Island (46 ° 32 9 S, 37 ° 51 9 E), 460–560 m, SAM A27547 . Paratype: St. 44 Marion Island (46 ° 41 9 S, 37 ° 50 9 E), 410–644 m, SAM A27160 .

Other material. St. 45 Marion Island (47 ° 00 9 S, 37 ° 55 9 E), 420–540 m, SAM A27161 .

Description

Colony erect, branching, delicate; made up of two alternating rows of club-shaped zooids. Autozooids with a broad distal portion, projecting from branch axis, 0.5–0.55X 0.25 mm, and a slender, proximal (axial) portion, 0.6–0.7 mm long; opesia elongate oval, occupying entire frontal surface of distal portion. A thick disto-lateral process extends from the frontal side of each autozooid, 0.5–0.6X 0.1 mm, typically no longer than the broad distal portion, slightly broadened at its tip where it bears five to six curved, cylindrical spines, up to 1 mm long; an additional spine present on the disto-basal side of each autozooid. Three types of avicularia present, each with a terminal rostrum, bearing a short, triangular mandible: a short pedunculate type, up to 0.2 mm long and 0.07 mm across the top, frontal in position and proximal to the frontal membrane; a larger, stouter, trumpet-shaped avicularium present latero-basally, midway along the length of the distal portion of the autozooid, 0.3 mm long, 0.12 mm across rostrum; this may be replaced by an even larger type, almost clavate in form, up to 0.7 mm long and 0.2 mm across the rostrum. Ovicell globular, flexed towards axis, wider than long (0.43X 0.4 mm), smooth, with faint striations radiating from the frontal lip.

Etymology

Named for the first author’s daughter, Bryony Branch.

Remarks

Cornucopina bryonyae sp. nov. is characterized by the combination of three types of avicularia and an unusually stout disto-lateral process, bearing spines along the distal third of its length. Polymorphic avicularia are characteristic of many species of Cornucopina , and their variety, morphology and point of origin on the bearing autozooid are taxonomically significant characters. The very stout, almost clavate avicularium, budded from a laterobasal position on the abaxial side of the autozooid, is presently unique to C. bryonyae , and distinguishes it from all other described species of the genus.

Cornucopina pectogemma ( Goldstein, 1882) is the common Cornucopina species at Marion Island, which is the type locality for the species. Colonies are flexuose, forming large, dense, feathery tufts up to 10 cm long. Autozooids are rather small, distal portion 0.35– 0.4 mmX 0.15–0.2 mm, proximal (axial) portion 0.5–0.65 mm long. The five to nine curved spines arise directly from the disto-basal wall of the autozooid. Very long and slender coach horn-like avicularia are characteristic, and together with the lack of a distolateral process bearing the spines, distinguish this species from C. elongata sp. nov. and C. bryonyae sp. nov. The characteristic avicularia, differently proportioned autozooids and fewer, shorter spines distinguish C. antlera sp. nov. from C. pectogemma .

Figures

Figure 4. (A) Cornucopina antlera sp. nov., SAM A27531, part of the colony showing autozooids and frontal avicularia, X40; (B) Cornucopina elongata sp. nov., SAM A27548, part of the colony showing autozooids, ovicelled autozooid and long avicularium, X40; (C) Cornucopina bryonyae sp. nov., SAM A27547, part of the colony showing autozooids, ovicelled autozooid and three types of avicularia, X40.