Rhynchozoon confusum (Calvet, 1906) Reverter-Gil & Souto, 2015

Reverter-Gil, Oscar & Souto, Javier, 2015, Redescription of some species of Bryozoa described by J. Jullien and L. Calvet in the NE Atlantic, European Journal of Taxonomy 157, pp. 1-17 : 13-15

Rhynchozoon confusum (Calvet, 1906) comb. nov.

Fig. 7 A–E; Table 4

Schizoporella confusa Calvet, 1906b: 217 .

Schizoporella confusa – Calvet 1907: 422, pl. 27, figs 12–13.

Material Examined

Lectotype (here designated)

MOROCCO: Talisman 1883 st. 10, 35º26’00’’ N, 06º48’46’’ W, off Cape Spartel , Strait of Gibraltar, 717 m, 10 Jun. 1883, Calvet coll., some fragments detached from a coral ( MNHN 4007 ).

Paralectotypes

MOROCCO: same data as lectotype ( MNHN 494, MNHN 1007, MNHN 1008, MNHN 2354).

Description

Colony encrusting, multilaminar, forming irregular crusts. Autozooids oval to irregularly polygonal, separated by very fine sutures on shallow grooves in young autozooids; boundaries becoming indistinct in later ontogeny. Frontal shield thick, finely granular, slightly convex, bordered by single series of marginal, round pores; rapidly covered by secondary calcification. Primary orifice orbicular to dropshaped, about as wide as long. Anter distinctly denticulate, with 16 to 25 rounded denticles. Proximal border almost occupied by shallow sinus flanked by two shoulders. Condyles small, inconspicuous, sloping towards sinus. No oral spines. Zooids rapidly developing a tuberculate peristome formed by 2 to 7 stout knobs, granular at apex but frequently broken in examined material; two lateral lobes most frequent and most developed; distal knobs may be absent or smaller. Some zooids may also have a single suboral umbo, smaller that the rest. One (occasionally two) avicularia present in most zooids, placed laterally, at midlength on zooidal margin and projecting beyond zooidal boundaries or lateral to orifice. Rostrum triangular, directed laterally or distolaterally; crossbar complete, without columella. Ovicells subimmersed, acleithral, with ectooecium formed by distal autozooid. Ectooecium covered by secondary calcification except smooth central area. Ovicell opening above zooidal orifice.

Remarks

Schizoporella confusa was described by Calvet (1906b; see also Calvet 1907) for several colonies growing on Lophohelia (= Lophelia ) collected at a depth of 717 m near Cape Spartel (Strait of Gibraltar). The original material is now preserved at MNHN and we here designate a lectotype from that material. The species does not seem to have been recorded since its original description.

The encrusting colonies, the zooids having only marginal pores, the distally denticulate orifice, with sinus and condyles, the well-developed peristome, the adventitious avicularia, and the ovicell with an exposed area of endooecium are all characters allowing the inclusion of the species in the genus Rhynchozoon Hincks, 1895 . Rhynchozoon confusum comb. nov. is characterized by the tuberculate peristome formed by 2 to 7 stout knobs, the lack of a suboral avicularium, and the lateral, triangular avicularium. Among the Atlantic-Mediterranean species of Rhynchozoon , only R. pseudodigitatum Zabala & Maluquer, 1988 may possess well-developed oral nodules, but this species is distinguished, among other features, by the suboral avicularium having an uncinate process defining a pseudospiramen.

Other species of Rhynchozoon , as for instance R. haha Hayward, 1988 from the Indo-West Pacific region or R. sexaspinatum Winston & Woollacott, 2009 from Barbados, may also develop umbos around the orifice, but the former is distinguished from R. confusum comb. nov. by its round orifice with a bowl-shaped sinus and knob-like condyles, and the large frontal avicularia; it differs from the latter by its keyhole-shaped orifice, with a large, rounded sinus and very large condyles, and three distinct types of avicularia.

Figures

Fig. 7. Rhynchozoon confusum (Calvet, 1906) comb. nov. A. Young autozooids in the colony margin; note the presence of small adventitious avicularia (MNHN 2354, paralectotype). B. Older zooids with indistinct margins and well-developed oral knobs (MNHN 494, paralectotype). C. Primary orifice (MNHN 4007, lectotype). D. Same, ovicell. E. Detail of an adventitious avicularium (MNHN 494, paralectotype).