A new genus of freshwater sponges consisting presently of two species is established. The two species are redescribed and compared to several other species which have been tentatively referred to genus Stratosþongilla but which may, pending further studies, be included in the new genus

Volkmer-Ribeiro, C.

English

MPG.PuRe

AMAZONIANA II 4 435-4+2 Kiel, Dez. 1970(From: Museu Rio-Grandense de Ciências Naturais, Pôrtg Alegre, RS, Brasil)Oncosclera - a new genus of freshwater sponges(Porifera-spongillidae) with redescription of two speciesby Cacrr,le Vo¡-rurn-Rrrunol)In 1963 the author described Sþongilla jewelli n. sp. mentioning the similarities existingbetween the new species and Spongilla nauicella Centen, lBBl. This species was incom-pletely described by Carter from a few gemmules found "in a twig in company withSþongilla reticulata and Spongilla þauþercula Br." (p. 87) and secured from the RiverAmazon, Recent accounts of S, nauicella in argentinien waters by BoNnrto and Ezcunne(1962) ancl BoNetto and Ezcunn.A. on Dn¡co (1964, 1967,1968) though offering asound ecological study of the species do not provide details of skeletal and gemmularstructures. Ilence a redescrip'tion of S. nauicellabased upon examination of more abundantmaterial is now given.In 1961 Dr. E.J. Flrtreu from "Max-Planck Institut für Limnologie" made anextensive and carefull collection of arnazonian spongillids and entrusted the authorwith study of this material. Postponement of this project for reasons beyond the controlofthe author delayed beginning ofthe study until 1968. As could be expected, S. nauicellawas found among the material from Amazon enabling the author to make a full com-parison of S. jewelli and S. naaicella and to confi.rm previous suppositions.In 1968 PnNNnv and Recer published their brilliant revision on the Spongillidae.Material of S. jeutelli and S. nauicella were lacking in the collections studied by theseauthors so were not dealt with in their revision. It is, however, apparent that neitherS. nauicellanor S. jeøelli can be placed in the Genus Stratosþongilla as redeûned by PoNNnvand R¿cnr (1968),. Presence of microscleres, of a pneumatic coat eventhough this maybe poorly developed or situated outside the layer of gemmoscleres and of a tubularforamen are characteristics of genus Stratosþongilla whích complelcly lack in these twospecies. Similarty the two species can not find place in any of the genera established orredeûned by PrNrvnv and Recnr (1968), thus indicating the need for a new genus toinclude S. jeøelli, S. nauicella and probably several other species which were also notrepresenteá in the materials studied by PnNNrv and Recnr, or which have been tenta-tively referred to the genus Stratosþongilla pending further studies. To meet this need,the new'genus Oncosclera, is now proposed by the author.Oncosclera, new genusType species - Sþongilla jeøelli Youcwøn, 1963 ,D efiniti on:Megasclere s: Siraight to slightly curved, slender to stout, occasionally microspined,more often smooth anfioxea to anfistrongyla.r) Fellow of "Consêlho Nacional de Pesquisas". Work partially supported by a grant from "Fun-daçäo de Aniparo à Pesquisa do Estado do Rio Grande do Sul"'435Microscleres: AbsentGemmoscleres: stout, short, feebly to strongly curved, extremely variable anfi-strongyla or anfioxea; part of the scleres conspicuously inflatecl at middle portion;usually spined, spines being more numerous at the extremities. Extreme shortening inlength may reduce inflated gemmoscleres to smooth or spined spheres.Gemmules: completely lack a pneumatic layer. Inner gemmular membrane for-ming as a small flask that siightly adheres to the outer gemmular membrane. Gemmo-scleres embedded usually tangentially in thick outer gemmular membrane in one ormore compact layers. Foramen or foramina with or without tube. Foraminal tube whenpresent short. Gemmules large, of the adherent type or free but always aggregated inthe basal portion of the sponge. Sponge forming thin crusts a few milimeters to 1 meterin diameter. Surface usually even.Sponges encrusting fìxed surfaces in fast streamsor water falls.Found commonly close to rapidsO ncosclera j ewelli (Y or,r*røn, I 963)Sþongilla jetuel/i Vor-rrr,rnn, 1963 p.271Spongilla (Stratosþongilla) jewelli Bourrro& or Dneco, 1968, p. 43Material: Paratypes and slides of types and paratypes, volrunn 1960 (MuseuRio-Grandense de Ciências Naturais. Catalog n" 1).Description: Sponge forming green patches from a few centimeters to one meterin diameter and not more than 0.5 mm thick. Encrusting rocky bottom .of the rivermargins, submerged rocks or òccasionally roots and sterris of aquatic vegetation. Inplaces not exposed to light as on the under sides of substrata the color is a dirty whiteindicating the green to be from associated algae. Surface even, velvetlike, with oscularadially arranged on top of relatively inconspicuous cones. The skeleton is formed ofdiscontinuous longitudinal fibers each about six spicules thick, from which secondarytransverse fibers arise at different levels. These transverse fibers anastomose with thosefrom the other closer main longitudinal fibers thus forming a network or reticulum ofelongated many angled meshes. Scales of spongin extend upward from the frameworkof one mesh to the next, thus the whole skeletal structure becomes a hollow but dis-continuous tube bearing a little resemblance to a honeycomb. At the surface of thesponge the main longitudinal fibers project beyond the scaly dermal membrane givingthe sponge its velvetlike appearance. The abundance of spicules and the mechànicaladvantage of the way they are meshed give a hard consistency to the entire sponge.Megascleres: Strong, smooth, straight, abruptly pointed anfioxea from lB0 to 225micra long with the largest number approximately 200 micra long and 24 micra wide(Fig. 1).Microscleres: AbsentGemmoscleres: short, thick, spined anfistrongyla conspicuouslyinflated at middleportion. Shape exceedingly variable with all intergrading forms between the cylindricaland the spherical forms, Spines more numerous at extremities or present only at theextremities (Fig. l).436Gemmules: The large, spherical, yellowish gemmules are very abundant and occurin a layer one to frve gemmules thick at the base of the sponge. The gemmules are freeand have an inner quite thick gemmular membrane loosely adhering to an outer gem-mular membrane. Gemmoscleres are embedded in the outer gemmular membranesome tangentially some at random in one or more layers. Pneumatic layer absent.Usually two foraminal apertures oriented at random. No foraminal tubes present(Fig. 2, 3).Distribution: Hithertho known only from type locality: "Passo da llha" TainhasRiver in the basaltic plateau northeastern part of Rio Grande do Sul State, Brasil.At this place waters of the river are swift and many small falls exist above and below.Remarks: Oncosclera jewelli shows a striking similarityl to Sþongilla rousselettiKtpree.TRIcK, 1906 and marked similarities to Spongilla macrosþiculata Sr:r,eurNs, 1919 and toSþongilla (Stratosþongilla) gilsoni ToesnNt, ,1912. Structures of skeleton and of gemmulesas well as spicular components of O. jewelli and S. rousseletti are pratically the same.The difference between the two species lies only in the tubular foramina of S. rousseletti.O. jewetti has in common with S. macrosþiculata strucuÍes of skeleton and of gemmulesas well as gemmoscleres. The two species differ in that ,S. macrosþiculata has gemmulesof the adherent type with short foraminal tube, and megascleres smooth anfioxea withswollen extremities. O. jeutelli shares with S. (5.) gilsoni form of gemmoscleres and struc-ture and disposition of gemmules which lack a foraminal tube and are of the free typein both species. They differ in S. (S.) gilsoni havíng spined instead of smooth megascleres.All these species lack microscleres. O. jetueLli shows yet some characteristics in commonwith Spongilla (Stratosþongilla) ponsi Borvntto and oe Dnaco, 1968 and Spongilla (Strato-sþongilla) tonolli BoNr.rto and oe Dnaco, 1968. These species have in common theabsence of microscleres, the absence of a pneumatic coat in gemmules and anfi.strongylousgemmqscleres which show a median inflation and spines concentrated at the extremitiesof scleres. Both species S. (5.) tonolli and S. (5.) þonsi are found encrusting the rockybottom of River Uruguay near rapids of Salto Grande.Oncoselera nauicella (Canr:nn, 188 1 )Sþongillanauicella Cenrr,n, 1881,p.87-Porrs, 1887p. 195-Wnr-rwsn lB95,p. ll9- Gnn, 1931e, i. 44 - BoNnrro& Ezcunn¿, 1962 p. 212; 1964 p.2+7 - Voxunn,1963 p.273. iSpongilla (Stratosþongilla) nauicella Boxntro& pn Dnaco 1967 p. 335; 1968 p.430.Sþongilla nauicella PrNNnv& Racnr, 1968 p. 4l tMaterial: Cuieiras River northern part of Amazon State, Brasil. E.J. FrrrreulB. 12.6i. (Museu Rio-Grandense de Ciências Naturais Catalog ngs. 4, 5,6,7).Description: Dry sponge forming small, dirty-white tufts fixed on extremities of thespiny processes of a Drulia sþ. Surface, as seen under magnification, spiny. Oscula fewand with no paiticular arrangement. Skeleton formed of main, not continuous longi-tudinal fibers 3 spicúles thick connected at different levels by transverse secondary fibersas,in O. jewelli. The reticular arrangement of secondary fibers is here very conspicuousdue to the little amounts of spongin present, Projection of the main longitudinal flbersgive the sponge its spiny surface, Consistency hard.Megascleres: slender, smooth, slightly curved, gradually pointed anfioxea, 130 to170 micra long and 6.5 micra wide, The thinner of these megascleres show a very slightmicrospination, a character already mentioned by porrs (lBB7 p. 196) when describlngO. naaicella (Fig. a).Microscleres: AbsentGemmoscleres: very short and thick to quite long and slender, smooth and tovarying degrees curved and medially inflated anfioxea. Shape exceedingly variablewith also spherical forms present. Because of complete intergrãding in lengtfi betweenshorter and longer gemmoscleres there can be no basis for dividing them into twã categories.On the other hand the longer gemmoscleres are readily told from the shorter megascleresby the strong curvature of the former (Fig.  ).438Gemmules: The large, globoeliptical, brown gemmules are of the adherent typeand occur singly. Inner gemmular membrane forms an independent flask with a shórtpore tube (Fig. 5) which fits into tube of the outer gemmular membrane. Gemmosclerestangentially packed together in several layers in the outer gemmular membrane forma strong armature (Fig.6). Efforts to separate gemmules from the substratum usuallyresult in breaking of the armature with the inner flask falling free. Pneumatic layérabsent.Distribution: Amazon River, Cuieiras River (Brasil) ;IguazuFalls of Paraná River,Paranâ River, IJruguay River and Plata River (Argentina).Remarks: Borqntto& or Dx.eco who have long paid attention to the large ecomor-phic variations of this species remark that in the fast wateri of high Paranâ River andUruguay River specimens of O. nauicella will develop small crusts not larger than 0.4 to0.5 cm' (megascleres not longer than 200 micra and 10 micra thick). In middle ParanâRiver and in Plata River however specimens of O. nauicella form crusts some meters indiameter and 4 to 5 cm. high (megascleres rêaching lengths of 250 to 330 micra and2Srnicta thick). This may be the ieason why all dccounti of occurrence of O. nauicellain usually swift amazonian waters up to now record the presence of only gemmules orof little specimens as the ones we are describing. In high paranâ River, -Bonnrro &Ezcunne (1964 p. 248) also record the occurrence of a few gemmules of O. nauicelløadhering to the ligament and valves of a freshwater bivalve (Anodontites traþezialis for-besianus).O. nauicella shows.marked similarities to Spongilla (Stratosþongilla) sclrubotzi WolrNrn,r9l3; spongilla (stratosþongilla) petri'cola BoNErro& op Dneco, 1967; spongilla (Euspon-gilla) stolonifer¿ BoNnrto& on Dneco, 1967 and to Sþongilla clementis AÑr.raNoar"n, 1909.To judge from w¿r,rNen's good though short description of s. (s.) schubotzi T¡othspecies have quitè identical smooth spicular components as well as very similar structuresof skeleton and of gemmules. Difference between these species lies in the great variabilityof megascleres and gemmoscleres in 'S. (^S.) schubotzi. A considerable identity exists alsåbetween O' nauicella and S. (S.) þetricola as already remarked by BoNerro and oB Dnaco(1967) when describing the latier species. The only differencå between the two speciesis the microspined gemmoscleres of ,s. (s.) þetricola. s. (8.) stolonifera has spined andsmooth slender anfioxea as rnegascleres, and though all gemmoscleres are mìcrospinedanfioxea they display the characteristic inflation and curvature of gemmoscleres asln O.naaicella. ,S. (¿.) stolonifera has also among its gemmoscleres some which are spherical.S. clementis, on the other hand, seems to be a form allied to S. (¿.) stolonifera. Both species50¡rFigure 1: Spicular components of Oncosclera jew¿lii: Smooth megascleres and spiny, medially inflatedgemmoscleres.Figure 2: Oncoselera jewelli: tansverse section of gemmule showing Figure 3 : Oncosclerajeuell¿': Inner gemmularthin inner gemmular mernbrane pulled inside and membrane was not takèn out ,ofgemmoscleres embedded in thick outer gemmular place and is shown to adheremembrane. .J:*ril#":""r gemmularo ¡5o¡,Figure 4: Spicular components of Oncosclera nauicella: Straight smooth megascleres and assorted.variations of the gemmoscleres.Figure 5: Oncosclera nauicellazlnnet gemmular membraneforming independent flask with short tube,have gemmoscleres with a terminal spine surrounded by spines at right angles to it,gemmules with a short foraminal tube, of the adherent type and lacking a pneumaticcoat and structure of the skeleton conforming the spicular arrangement seen in O.nauicella and O. jetøelli.Discussio nThe new genlrs is closely related to genus Stratosþongilla as redefined by PnNNnv andRecEK (1968). It differs frorn Stratosþongilla in the absence of free microscleres frominner symplasm and dermal membrane, in the total absence of a pneumatic layer ingemmules and in the great variability and peculiar form of gemmoscleres.Perunr,v and RecEr (1968) though advancing the probability of erecting a new genusgathering all those species of Stratosþongilla devoid of microscleres did not attempt sucha division because specimens of such forms were missing in the collections studied bythese authors. A Study of plenty of material of O. jewelli and of complete specimens ofO, ntiuicella rendered it evident that these two sponges could not be placed under Strato-sþongilla and that creation of a new genus, for at least these two forms, could not bepostponed.On the other hand one cannot escape comparison of these two species with all thosedevoid of microscleres and provisionally placed :under Stratosþongilla, What such a com-parison brings out is a number of striking similarities both among spicular componentsand among structures of skeleton, not to speak of a marked preference for a sameparticular habitat.Pending renewed occurrences and study of all the species here related to O. jeøelli andO. naaicella the new genus would consist of two main groups of species with two inter-grading species in between. One group would be represented by O. jewelli and relatedspecies with anfistrongylous gemmoscleres passing through S. (5.) þonsi and S. (5.) tonolli,with gemmoscleres that start taking stronger curvature and slendering, to the group ofspecies with anfioxeous gemmoscleres. O. naaicella would stand, up to now, for the mostextreme representant of this last group. At the same time location along this gradientof species from O. jewellito O. nauicella seems to progress from species showing preferencefor turbulent watels to species like O. nauicella attaining full development in more calmwaters,SummaryA new genus of freshwater sponges consisting presently of two species is established.The two species are redescribed and compared to several other species which have beententatively referred to genus Stratosþongilla but which may, pending further studies, beincluded in the new genus.SumárioIJm novo gênero.de esponjas de água doce é caracterizado no presente trabalho bemcomo redescritas as duas espécies que o integram. Apontam-se ainda várias afinidadeseSistentes entre as espécies redescritas e diversas outras até aqui provisoriamente inclu-idas no gênero Stratosþongilla mas que mediante novos estudos serão muito provavel-mente incluidas no novo gênero.4+LFigure 6: Oncosclera naaícella: Outer gemmularmembrane showing several layers ofgemmoscleres tangentially embedded.'*så'"¿'Acknowledgements : The author is indebted to Dr. E. J. Frrrreu from ,,Max-Planck-fnstitut für Limnologie" for one of the most valuable collections of arnazonianspongillids ever gathered as well as for constant interest and encouragement. She wishesto express heartily thanks to Dr. M. E.Jnwnrr-, for assistance in preparation of the manu-script and to Dr. J. F{¿uspn from "I]niversidade do Vale do Rio dos Sinos" for all themicrophotographing.ReferencesANN.a'noelE, N. (1909): Freshwater sponges in the collection of the United States National Museum.I. Specimens from the Philippines and Austraìia. - Proc. U. S. natn. Mus. 36: 627-632,BoNtr,rro, A. A. & Ezcunna, I. (t962): Dos Nuevas Esponjas Para el Paranâ Medio. - physis. B.Aires 23 (65): 209-2L3Bouarro, A. A. & EzcuRilA oe Dnaco, I. (1964): Esponjas Del Paraná Medio e Inferior. - Anaisdo Segundo Congresso Latino-Americano de Zoologia, It 245-260.Boxnrro, A. A. & Ezcunxe oo Dnaco, I. (1967): Esponjas del Noreste Argentino. - Acta zool.lilloana. 23 :. 33L-347.BoNerto, A.A.& Ezcunna DE DRAGo, I. (1968): El Genero Spongilla Lamarck en el Rio lJruguay(Porifera, Spongillidae). - Physis. B. Ai¡es 27 (7s): 429-436.Canrnn, H.J. (1881): History and Classification of the known species of Spongilta. - Ann. Mag.nat. Hist. 7 (5): 77-107.Gea, N. G. (1931): A contribution toward an alphabetical tist of the known fresh-water sponges. -Peking nat. Hist. Bull. 5 (1): 31-52.Krnrtautcr, R. (1906) : Report on the Porifera, with notes on speçies from the Nile and Zambesi.Zoologìcal results of the third Tanganyika Expedition. - Proc. zool. Soc. Lond. 1 : 2LB-227.PrNIvrv, J. T. & R.a.cor, A. A. (196s): Comprehensive Revision of a Worldwide Collection of Fresh-wãter Sponges (Porifera; Spongillidaê). - U. S. Nat] Mus. Bttll. 272: I-'60.Porrs, E. (1887): Contribution towards a.synopsis of American forms of freshwater sponges withdescription of those named by other authors and from all parts of the world. - Proc, Acad,nar. sci. Philad. ¡g: t58-279.SrnrucNs, J, (1919): Two new African freshwater sponges. - Ann. Mag. nat. Hist. 3 (9): 9a-100.Tonsnnr, E. (L972): Description de Spongitla (Stratosþongilla) gilsoni n,sp. - Annls Biol. lacustre 5:187-190.Vorrur,n, C. (1963): Spongilla jeuelli n. sp. frorn Fresh-Water Sponge atBlrazil. - Anais. Acad.bras. Cienc. 35 (2)': 271-273.'WellNen, W. (1895): Spongillidenstudien III. Katalog u. Verbreitung der bekannten Süßwasser-schwämme. - Arch. . Naturgesch. 6I': I14-L44.Author's addressCecilia Volkmer-RibeiroMuseu Rio-Grandense de Ciências NaturaisAv. Mauá 1855Caixa Postal ll88Pôrto Alegre - RSBRASIL442

Oncosclera - a new genus of freshwater sponges (Porifera - Spongillidae) with redescription of two species

Abstract

Similar works

Full text

Available Versions

MPG.PuRe