Acorania enmediensis, López-Fé, 2006

López-Fé, C. M., 2006, Some bathyal cheilostome Bryozoa (Bryozoa, Cheilostomata) from the Canary Islands (Spain, Eastern Atlantic), with descriptions of three new species, a new genus, and a new family, Journal of Natural History 40 (29 - 31), pp. 1801-1812 : 1809-1811

Acorania enmediensis sp. nov.

( Figures 9–13 ; Table IV)

Material

A few colonies, most in ‘‘ Madrepora 2’’. Only the holotype is well developed and preserved, but the ancestrula is overgrown and is not branched. Two paratypes have been chosen to complete the description.

Holotype: complete colony 2 cm high, not branched, with ovicells. The distal half used for SEM pictures ( Figures 9, 10, 12, 13 ) ( MNCN 25.03 /3726) . Paratypes: paratype 1, very young colony, with ancestrula and three autozooids in two branches, used for SEM ( Figure 11 ) ( MNCN 25.03 /3727); paratype 2, old colony, broken and branched ( MNCN 25.03 /3728) .

Other material. One young colony on ‘‘ Madrepora 1’’ (MNCN 25.03/3731) and a few ancestrulae on ‘‘ Madrepora 2’’ (MNCN 25.03/3734).

Description

Colony erect, branching, delicate (branches 1 mm wide), with four rows of alternate autozooids whose frontal planes are angled at 45 ° to each other. Consequently, the branch has a frontal face in which the four rows are visible and an abfrontal face devoid of apertures. The autozooids are elongate, with the frontal wall perforated by pseudopores except in a small area proximal to the orifice. The orifice is almost circular, slightly wider than long, with two proximolateral condyles and a wide poster. A very low peristome, seen by SEM, is developed on both sides of the anter, but it is interrupted distally and does not surround the poster. The ovicell is hyperstomial, not closed by the operculum, prominent and smooth, with the ectooecium fully membranous except for a basal rim, and a fully calcified imperforate endooecium. Each autozooid bears usually two (less frequently only one) small elliptical avicularia, proximolateral to the orifice, with a complete bar between the opesia and the rostrum. Supplementary avicularia, directed outwards, may exist on the margins of the frontal wall of old zooids. Ancestrula erect, tatiform, with 10 marginal spines. Both transversal and lateral walls between zooids are double. Interzooidal communication by mural chambers, each one with a uniporous septulum.

Etymology

The specific name enmediensis refers to the Enmedio volcano.

Discussion

Acoraniidae fam. nov. is introduced to accommodate Acorania gen. nov., whose combination of characters is unique and does not fit any described family of cheilostomes. Many genera within the Lepraliomorpha have perforated frontal walls and orifices without a lyrula. Most of them are included in the superfamilies Schizoporelloidea Jullien and Smittinoidea Levinsen. But they do not have an ovicell with the features of Acorania gen. nov.: frontally uncalcified ectooecium, calcified imperforate endooecium and not closed by the operculum. The only exception is the Pacific genus Torquatella Tilbrook, Hayward and Gordon , provisionally included by the authors in the family Teuchoporidae Neviani ( Tilbrook et al. 2001) .

Acorania gen. nov. must not be included in the Teuchoporidae because it differs from the last diagnoses of this family ( Gordon 1984; Hayward and Ryland 1999) in the presence of uniporous mural chambers for interzooidal communication and the imperforate ovicell, while Teuchoporidae has basal pore chambers or multiporous septula and perforate ovicell. Torquatella is the only Teuchoporid genus with an imperforate ovicell, but it must be remembered that the inclusion of Torquatella in this family was only provisional ( Tilbrook et al. 2001), and that Torquatella , as other teuchoporids, has multiporous septula.

In addition, the Teuchoporidae are represented in the Atlantic by Phylactella Hincks , which is very different from Acorania gen. nov.: Phylactella lacks avicularia and has a lyrula, perforated ovicell, and basal multiporous chambers ( Hayward and Ryland 1999). A close relationship between Phylactella and Acorania gen. nov. seems unlikely.

Other genera have similar ovicells, like the austral taxa Isoschizoporella (Eminooeciidae) and Hippadenella (Smittinidae) , but they have imperforate frontal walls and multiporous septula ( Hayward 1995). Further, the ovicells of the Eminooeciidae are associated with polymorphs ( Hayward 1995), which does not occur in Acorania gen. nov.

The Acoraniidae fam. nov. may be placed in the superfamily Schizoporelloidea Jullien because of its lepralioid frontal wall, orifice without a lyrula, and ovicell with membranous ectooecium and imperforate endooecium, shared with schizoporelloideans such as Arthropoma , Kymella , Fenestrulina , and the Lacernidae Jullien as redefined by Parker and Gordon (1992), although, in contrast with the new family, the ovicell is closed by the operculum in all these taxa.

Nevertheless, any assignation to a superfamily within the Lepraliomorpha may be considered provisional in the current state of knowledge. The superfamilies of Lepraliomorpha, and especially the very diverse Schizoporelloidea , need revision and clarification of diagnostic characters. Gordon (1994) re-established the Smittinoidea Levinsen, in which the two layers of the ovicell are calcified (which precludes the inclusion of Acoraniidae fam. nov. in it), but since then, several works differ in the assignation of some families to either Schizoporelloidea , Smittinoidea or others. An example may be the above-mentioned Teuchoporidae , included in the Schizoporelloidea by Hayward and Ryland (1999) and Bock (2006), but in the Smittinoidea by Tilbrook et al. (2001).

Figures

Figures 8–13. (8) Distansescharella alcicornis (MNCN 25.03/3723). (9–13) Acorania enmediensis gen. et sp. nov.: (9–12) holotype (MNCN 25.03/3726); (13) paratype 1 (MNCN 25.03/3727). (9) Autozooid with ovicell and avicularia, the broken ovicell at right shows the unfused endooecium and ectooecium. (10) Growing tip of a branch. (11) Uniporous chamber, distal side, with pore and limit of the chamber (arrow). (12) Inner side of the frontal wall, with condyles. (13) Ancestrula and first zooids.