Cigclisula osburni n. sp.

(Fig. 16, Table 4)

Trematooecia hexagonalis: Osburn 1952: 503 (part), pl. 60, fig. 7. [Gulf of California and Mexico]

Not Holoporella hexagonalis Canu & Bassler, 1930a: 38, pl. 7, fig. 1. [Galápagos Islands]

Trematooecia hexagonalis: Soule 1961: 59 . [California]

Trematooecia hexagonalis: Soule & Soule 1964: 40 . [Isla Conchas, California]

Material examined. Holotype: USNM 603769, ‘ Trematooecia hexagonalis’, Hancock Stn 229, San Jose del Cabo, Baja California, Mexico, 149 m. Additional specimens: USNM 603770, ‘ Trematooecia hexagonalis’, Pacific coast of Panama .

Diagnosis. Encrusting, zooids with 1–2 rows of large marginal pores; ooecium tubercular and ectooecium with longitudinal band of 27–39 irregular pseudopores.

Etymology. Named in recognition of the major contribution of Raymond Carroll Osburn (1872–1955) to bryozoan taxonomy.

Description. Colony encrusting, uni- to multilaminar. Zooids hexagonal to polygonal, as long as wide, delimited by slightly raised lateral walls. Frontal shield thickly calcified, with 1–2 rows of 20–40 marginal pseudopores and areolar pores, smooth. Primary orifice large relative to area of frontal shield, centered, subelliptical, longer than wide, sunken, with arcuate anter and deep semicircular poster separated by 2 down-curved condyles set nearly mid-length. Secondary orifice surrounded by 4–5 (usually 4) solid tapered tubercles. Suboral avicularium absent. Frontal avicularia small, elliptical, single, placed at zooidal margins. Ooecium subglobose, inclined to zooid surface, often tubercular; ectooecium with longitudinal band of 27–39 irregular pseudopores.

Remarks. Cigclisula osburni n. sp. was previously attributed to Trematooecia hexagonalis (see remarks under C. porosa), which it resembles in having encrusting colonies, a secondary orifice with solid tubercles and no interzooidal avicularia. Differences include zooid size (larger in C. osburni n. sp. than in T. hexagonalis), the number of frontal pseudopores (20–40 in C. osburni n. sp., 36–51 in T. hexagonalis) and the ectooecium (porous in C. osburni n. sp., with a U-shaped membranous area in T. hexagonalis).

Cigclisula osburni n. sp. resembles C. psammophila, Cigclisula perforata n. sp. and Cigclisula fistulosa n. sp. in having encrusting colonies, a secondary orifice with solid tubercles and no interzooidal avicularia, but differs in having 1–2 rows of 21–41 marginal pores and an ectooecium with a longitudinal band of 27–39 irregular pseudopores. The primary orifice of C. osburni n. sp. is shorter than in C. perforata n. sp. and its zooids and frontal pseudopores larger than in C. fistulosa n. sp. (Table 3).

Distribution. Eastern Pacific: California and Mexico.