Rivista Italiana di Paleonrologia e Stratigrafia Dicembre 1999 NOTA BREVE - SHORT NOTE AMPHIBLESTRUM (AVICULAMPHIBLESTRUM) RUGGEROI SP N., SUBGEN. N. (BRYOZOA) FROM THE \TESTERN MEDITERRANEAN SEA A. ROSSO Recehed April 4, 1999; accepted September 6, 1999 ,^n"^n.u, ruords: Bryozoà' new taxa' deep-sea, Recent, Mediter- Riassunto. Amphible stwm (Aviculamphible strwm) ruggeroi sp.n. viene descritta e per essa viene creato un nuovo sottogenere all'inter- no del genere,4mphiblestrum. La specie proviene da fondi cìrcalitorali profondi ed epibariali del Canale di Sicilia e da località del Mediterra- neo nord-occidentale. 11 nuovo sortogenere è creato per distinguere, all'interno del genere Amphiblestrwm, specie che hanno oltre ai tipici aviculari awentizi, anche grandi aviculari interzoeciali, entrambi sviluppati a partire dt dietellae. Abstract. A new species and a new subgenus Amphibles*um (Aoiculampbiblestrum) rwggerol sp.n. are described from deep circalit- toral-epibathval bottoms from the Sicily Strait and the north-western Mediterranean. The new subgenus is created to distinguish, within Amphiblestrum, species u.ith both gymnocystal adventitious and large interzooidal avicularia, both originating frorn basal pore chambers. Introduction. During the study of some fossil and Recent species belonging to rhe genus Amphiblestrwm Gray, i848, the examinarion of specimens from the Mediter- ranean lead to the discovery of a new species. It roughly resembles Amphiblestrurn auritum (Hincks) from Atlantic-Mediterranean shallow water environmenrs (see Rosso, in press). FIowever, the new species, besides gymnocystal adventitious avicularia, shows also large interzooidal avicularia, a feature not recorded, until nos/, for species referred to this genus. The generic attri- bution of the presenr new species and rhe introduction of a new subgenus Aoiculamphiblestum within Amphi- blestrwm Gray, 1848 is discussed. Systematic Paleontology Class GymnoIaemata Allman, 1856 Order Cheilostomatida Busk, 1852 Suborder Anascina Levinsen, 1909 Family Calloporidae Norman, l9O3 Genus Amphiblestrum Gray, 1848 Subgenus Aoiculamphiblestrurn subgen. n. Etymology. From "avicularivn" tnd Amphiblestum - refcrrins to the presence of addirional interzooidal avicularia. Fig. 1 Di'rributron of An[ltiblc strum (Av i c u latnp b tb le s t um ) ,uUeroi rp. n., subgen. n. Encircled star : studied .etnples; r rirngle : or hcr localities. Drpartimento di Scienze Geologiche, Sezione di Oceanologia e Paleoecologia, Catania University, Corso Itala, 55, I-951,29, ross o @ mbox. unict. it. A. Rosso Fig.2e-b- Anphiblestum (Ariculatnphìbles*um) ruggeroi sp. n., subgen. n. Holot,vpe. Periancesrrular zooid (a) s'itir six margin;il spines and the proximal avicularium and ,r mature zooid (b) with four oral spines persisting in prcsence of the ,.r-icell. Note the peculiar position of thc avicul:rrium. Sicily Strait, Sample CR-90-8. Scale bar = 2OO Fm. Diagnosis. As the genus, but with the addition of interzoordal avicularia, besìdes the gymnocystal adventitious ones, both originating fron'r basal pore-chambers. Remarks. As for the species: see above. Amphiblestrum (Aviculamphiblestrum) ruggeroi sp. n. (Fig. 2-a) 1988 Amphiblestrunt minax - Zabah & Maluquer, pl. 3B. 1988 nonAmphiblestum rninar - Za'bilt 8r Maluquer, p. 82, fig. 93. 1993 Amphiblestrum sp. Di Geronimo et al., tab. 3. 1993 Amphiblestwn fletningi, Zrbah et al., p. 68, fig. 2. Material. Specimens come from Post-\Wùrmiin thanato- coenoscs (Fig. t), collected from 201 (sample CR-90-15) to 212 m (semple CR-90-8), on and near the Graham Bank, in the Sicily Straits (Di Geronirno et al., 1993). Etymology. Frorn the Author son's name: Ruggero. Types. The seìected holotype is a colony encrusting a valve of Neopycnodonte cochlear (Poli) on a Scleractinian calvx of Dendrophyl- lia cornigera (Lamoroux). P:rratypes: one large and five young srnall colonies from the same sample. They all are dead and originate from st. CR-90-8, 212m,37" 14.38'N; 12" 42.31.'E. Types are housed in the Palaeontological Museum of Catania University (PMC) and are ìabelled PMC. 89. 26-2-1998. Description. Colony encrusting, flat. Zooids oval ro pyriform (Figs. 2a, b),425-566 (512, N = lO) gm long and 288-517 (334, N : 10) Lrm 1arge, contiguous but well separated by grooves. Area oval ro pyrifornl, occupying 4/5 ol the total length, marked by. a rhin crenellate raised rim. Opesia oval ro subquadrangular, rarely with almost midway consrricrions. Six to four dis- tal thin spines (see Fig. 2), four persisting on ovicellare zooids with the distal pair close to the orifice of the ovi- celì. Cryptocyst finely gr,rnuì.rr. nrrrorv rrnd sreeply ris- ing from the distal edge of the opesia; proximally large and grading into the rim. Gymnocyst smoorh, sreeply dipping away from the rim, only proximally produced, partly obscured by the avicularium ir supporrs. A singie gymnocystal columnar avicularium prox- imally located, occupying one third of the zooidal width (Figs. 2a, b); the sharply triangular rosrrum sianted transversely or distal-laterally upwards; condyles stour; 'cross-bar absent; opesium elliptical. Zoojds placed dis- tally to an ovicell with one, often two, gymnocysral avic- ularia, laterai or disto-1ateral, symmetricaliy and trans- versely placed to the ovicell; the rostra pointing towards the middle forming a "roof ". Interzooidal avicularia more ofren near the colony boundary (Figs. 3a, b), polygonal c.a. one half rhe length of the autozooids. often as wide as an aurozooid. Ros- Arnphíblestrum (Aaiculamphiblestrum) from ruestern Mediterranean sea Fig. 3e-b - Ampbibles*urn (Ariculanphiblestum) rugeroisp. n., subgen. n. HoLotypc. Interzooidal avicularium at the colony edge and (b) an orher sector showing several interzooidal avicularia and an ovicell ovcrarched by two conver{ing ldventitions avicularìa. Sicriy Streit, Sample CR-90-8. Scale bar = 200 urn. trum horizontally 1ying, long, straight with thin, raised walls; the apex curving downwards. Mandibular pivot blunt. Oral shelf wide, opesium e1liptical, proximally bordered by a finely granular, concave rim. Oviceli globular, prominent, seemingly not closed by the operculum, with a frontal, finely granular cres- centic area separated by a raised suture from the mar- ginal smooth ectoecium (Figs. 2b, 3b) . Ancestrula (Figs. 4a, b) smaller than other zooids (340 ptm long and 250 prm wide) but similar in shape, with nine spines, budding a first distal zooid and tvro secondary disto-lateral ones, each having six spines, the more proximal pair at the beginning of the opesrum. New zooids are budded contemporaneously in distal and latero-proximal directions allowing the colony to achieve a rounded outline. The three first budded zooids lack the gymnocystal avicularium. Remarks. Colonies are very similar to species of the genus Ampbib/estrum Gray, 1848 for most of their characters, Nevertheless, they have interzooidal avicu- Iaria, a very important diagnostic feature (cf. Gordon, 1984). Such avicularia actually originate from basal pore chambers (see Fig. 3a). This condition is shared with smaller, f rontal adventitious avicularia of the same species and also with those described in other species referred to Amphyblestrum such as A. flemtngl (Busk) from rhe NE Arlanric. The new subgenus Aaiculamphi blestrum is, thus, introduced, within Amphiblestrum, to stress rhe nresence ^{ ltto" i.t"t"^^ì.{ .l .rvicullria,.'6" besides the sma11 gyn-rnostal ones, both having a conr- mon origin and different position and size. This also happens in species of Chaperiopsis Uttley, 1949, such as C. multifida (Busk) (Gordon, pers. com.) and Callopora Gray, 1848, such as C. smttti (Kluge). Virhin the genus Amphiblestrum, this peculiar feature is presently known only for A. ruggeroi. Large interzooidal avicularia devel- op from lateral or disto-lateral basal pore chambers, attain large sizes, almost sin-rilar to rhose of zooids, and show a random location among t1-re zooids, although rhear rr" mnre enmmnn ncîr rL" "^l^.t"".,../ nr,Ìrglns. Mandibles were not observed but thel- are presumably straight and pointed rs, in rhe Family Calloporidae, mandibles are usually quite close in shape to their skele- tal rostra (Vinston, pers. com.). The specimen figured loy Zaba\a & Maluquer (1988: fig. 38) and Zabala et al. (tll:) have been syn- onymised with,,1. ruggeroi as it seems to share with the present species all diagnostic features. Zabala et al. (1993), indeed, doubtfully referred their material to A. flemingi (Busk) stressing differences in the number of 168 A. Rosso !ig. 'la-b- Amphiblestutn (Aticulamphiblestrum) rugerol sp. n., subgen. n. A paratype. Ancestrula (a) and periancestrular arer (b) showing firsi astogenetic budding pattern. Note the interzooidal avicularium laterally budded from the rncestrula. Sicill' g152i1, Sanple CR-90-8. )cîtc Dîr - luu urn. spines (4, rarely 6), the absence of the proximal gianr spine, the shape of the opesium and that of the ovicell frontal area. All these characters are obvidus from pho- tos and they are shared with ,4. rugeroi. Moreover, the figured ovicells show distal single or paired avicularia transversely placed to form rhe "roof " peculiar to ,4. ruggeroi and not described for any other species in the genus. The specimen from rhe Zabala collection figured by López de la Cuadra & García Gomez (199a) is dif- ferent and actually belongs to A. flemingl (Busk). Distribution. The species s/as found in two samples from Sicily Straits, between 201 (sample 15) and 212 m (sample 8) (Di Geronimo et al., tl13;. Specimens were all dead, when sampled. Community is rich and diversi- fied in the former and extremely scant in the latter. Thanatocoenoses (i. e. skeletal remains present in the bottom sediment) are more rich and diversified. Both testify the mixing of outer shelf (deep circalittoral) rocky bottom organisms or skeletons (belonging to the rocky offshore assemblage) with faunas peculiar to upper slope (epibathyal) muds (bathyal mud assem- blage). Samples contain sma1l branches of the gorg- onacean Corallium rwbrum (Linnaeus), large fragments of the scleractinian Dendrophyllya cornigera (Lamoroux) and large valves of the mollusc Neopycnodonte cocltlear (Poli). Living bryozoans are scant but diversified com- prising both rigid erect species (Annectocyma tubwlosa, Entalopboroecia deflexa, E, gracilis) and unilaminar species among which Puellina (Cribrilaria) innomrnata, P. (Glabrilaria) ped.uncwlata, Escharina hyndmanni, E. au lgari s and Cras sim ar gi n a t e I I a s o I i d u I a encrus rin g lar ge molluscan and scleractinian skeletons. Dead specirnens mainly belong to erecr species: Terr.,ta irregularis, Hornera frondiculata, H. Iichenotdes, Palmicellaria c[. elegans, Sertella couchi biarticwlata, S. septentrionalis, Tes- saratloma borea/e and Scrupoce/larta delili. E,ncrusting taxa are also common Pue/lina (Cribrtlaria) Lnnomtna- ta, P. (C.) radiata, Crassimarginate/la solidula and Escba- rina oulgaris. A. ruggeroi is also present in the Blanes Canyon from 180-350m where colonies encrusr a par-rly alive colony of the deep-sea scleractinian Madrepora oculata (Ztbala et al., tllt;. The species is, therefore, known only from deep- sea (lower circalittoral to epibathyal) sites from the Western Mediterranean. AcknouIed,gements, I arn grrteful to: l)r. C. M. López de la Cuadra (Dep. Fisiolo- gia y Biologia Animal, Sevilla), Dr. J. Vinston (American Museum of Natural History New York) for useful inforrnation; Dr. D. P Gordon (New Zealand Oceanographic Institute, .Wellington), Dr. I.-G. Harmelin (Station Marine d'Endoume, Marseille) for discussions and suggestions. I would also thank Mr. O. Torrisi (Isrituto Internazionale Vulcanologia, CNR, Catania) for SEM assisrrnce. Paper financially supported by Min. Ris. Agr. Al. For (Prof. Di Geronimo) and MURST lRosso). Di Geronimo I., Rosso A., Sanfilippo R. (1993) -The Coralli- um rwbrurn fossiliferous banks off Sciacca (Strait of Sici- ly). In: Cicogna F. & Cattaneo-Vietti R. (eds): Red Coral in the Mediterranean Sea: Art, Hystory and Sci- ence. Min. Ris. Agr. Al. For., pp. 75-107, Roma. Gordon D. P (1984) - The Marine fauna of New Zealand: Bry- ozoa: Gymnolaemata from the Kermadec Ridge. Nezo Zealand Oceanographic Institute Memoir 91, pp. 1-198, \X/ellington. Rosso A. (in press) - Amphiblestrum Gray, 1848 (Bryozoa Cheilostomatida) in the Atlantic-Mediterranean area, with description of a new species. Journ. Nat. Hist., London. 469 López de la Cuadra C.M. & García-Gómezl.C. (99a) - Bry- ozoa Cheilostomara: the genus Amphiblcstrum in the \flestern Mediterranean and the f vst Sessibugula of Atlantic waters. Journ. Nat. Hist., v. 28, pp. 683-693, London. ZabalaM. & Maluquer P (1988) - Illustrated keys for the clas- sifications of Mediterranean Bryozoa. Treballs del Museu de Zoologia, v. 4, pp. 1-294,Barcelona. ZabalaM., Maluquer P & Harmelin J.-G. (1993) - Epybiotic bryozoans on deep-water scleractinian corals from the Catalonia slope (western Mediterranean, Spain, France). Scientia Marina, v. 57, pp. 65-78, Barcelona. Amphiblestrwm (Aoiculamphiblestrum) from zaestern Meditenanean sea REFE,RENCES