Marcusadorea, Vieira & Migotto & Winston, 2010

Vieira, Leandro M., Migotto, Alvaro E. & Winston, Judith E., 2010, Marcusadorea, a new genus of lepralioid bryozoan from warm waters, Zootaxa 2348 (1), pp. 57-68 : 58-59

Genus Marcusadorea n. gen.

Type species. Marcusadorea jamaicensis n. sp.

Description. Colony encrusting, unilaminar, uniserial and runner-like, to multiserial and patch-like with erect tubular branches. Autozooids large, irregularly polygonal to rectangular, separated by distinct boundaries. Frontal shield convex, granular-tubercular, sometimes perforated by small, sparsely distributed pseudopores irregularly placed on surface and by larger marginal areolar pores. Primary orifice subcircular; very small condyles may occur; lyrula and sinus lacking. No oral spines. Peristome surrounding orifice, higher laterally and distally, with or without peristomial avicularium. Vicarious avicularia lacking. Ooecia prominent, porous, with aperture opening inside peristome and not closed by operculum.

Etymology. The new genus is named in honour of Dr Ernst Marcus (1893–1968) for his invaluable contributions to bryozoology. Marcus + Latin n. adorea, f. = glory, honour.

Diagnosis. Marcusadorea new genus is characterized by the presence of a well-developed peristome surrounding the orifice, a granular-tubercular irregularly porous frontal shield, large marginal pores and an ovicell opening inside the peristome.

Remarks. Holoporella tubulosa Canu & Bassler, 1928 , originally described from the Caribbean, Coleopora corderoi , described from Brazil, and “ Cosciniopsis ” efatensis Tilbrook, 2006 from Solomon Island are here reassigned to the new genus Marcusadorea . The diagnostic features of Marcusadorea are clearly visible in the figures of Canu & Bassler (1928: pl. 24, fig. 6), Marcus (1949: fig. 23) and Banta & Carson (1977: fig. 6C). Marcusadorea efatensis ( Tilbrook, 2006) n. comb., from Efate ( Vanuatu), was uncertainly assigned to the genus Cosciniopsis by Tilbrook (2006: 240) because it does not fit perfectly the definition of the genus as originally established by Canu & Bassler (1927). In fact, the type species of the genus, Cosciniopsis coelatus Canu & Bassler, 1927 , originally described from the Philippines, is characterized by large zooids with very thick, pigmented frontal shields with small pseudopores, but lacking marginal areolae, and with the ovicell closed by an operculum. Its zooidal features, an irregularly perforate frontal shield, presence of marginal areolar pores, raised vertical walls, and basal pore-chambers indicate close affinities with Marcusadorea jamaicensis n. sp., Marcusadorea corderoi n. comb. and Marcusadorea tubulosa n. comb., led us to reassign this species to the new genus Marcusadorea .

The genus Coleopora was established for Coleopora verrucosa Canu & Bassler, 1927 , based on specimens from Jolo Light, Phillipines (Albatross Station 5137); strangely, the holotype was catalogued twice as USNM 7969 and 8465 (J. Sanner pers. comm. 2009), but only one number appears two years later ( Canu & Bassler 1929). In the original description of the genus Coleopora, Canu & Bassler (1927) reported the globular ovicells not closed by an operculum; however, examination of all material identified by Canu & Bassler as C. verrucosa , including the holotype (USNM 8465), showed colonies without ovicells (J. Sanner pers. comm. 2009). In addition, the frontal shield of C. verrucosa is uniformly perforated, without sizedifferentiated marginal areolar pores, rather than irregularly perforated with large obvious marginal pores, characteristic of Marcusadorea .

Suboral avicularia are present in M. jamaicensis , M. tubulosa and M. corderoi , but are lacking in M. efatensis . The avicularium is placed on the inner side of the long and tubular peristome, as in Drepanophora Harmer, 1957 . However, Marcusadorea differs from Drepanophora in lacking the conspicuous denticle projecting into the peristome at the base of the avicularium and in usually having small pores in the frontal wall. Species of Drepanophora also have a different ooecium structure and an imperforate umbonulomorph frontal shield with lateral areolar pores ( Gordon 1993: 206).

The placement of Marcusadorea at family level among the Schizoporelloidea is uncertain. Elongation of the peristome has led to the incorporation of an oral avicularium and the opening of the ovicell, as in smittinids, but the ooecia are constructed differently. In the two families of Smittinoidea Levinsen, 1909 with known ovicells ― Smittinidae Levinsen, 1909 and Bitectiporidae MacGillivray, 1895 ― the zooidal frontal shield ranges from fully umbonuloid (with only marginal areolar septular pores) to fully lepralioid (with an evenly pseudoporous shield and some of the marginal pores functioning as areolar septular pores), but the ovicell has an ectooecium with usually relatively large pores that show the inner entooecial layer beneath. The ovicell of Marcusadorea also has two layers, but with the calcified entooecium concealed and the ectooecium appearing as in some Schizoporelloidea . Taxa with similar ooecia include some Lanceoporidae Harmer, 1957 ― Calyptotheca Harmer, 1957 , Emballotheca Levinsen, 1909 and Parmularia MacGillivray, 1887 ― in which the entire structure consists (as seen in sectioned material) of the completely calcified entooecium, coelomic cavity, pseudoporous calcified ectooecium, overgrowing porous secondary calcification, hypostegal coelom and an external membrane (A. Ostrovsky pers. comm. 2009).

Despite the similarity of ooecial structure among Lanceoporidae , the orifice of Marcusadorea resembles those of several Stomachetosellidae Canu & Bassler, 1917 and the external appearance of ovicells is identical in the fossil genus Saevitella Bobies, 1956 . Owing to such inconsistency, until a comprehensive revision of the Schizoporelloidea is done, we consider the systematic position of the new genus Marcusadorea uncertain at family level and within Schizoporelloidea .