Plakortis ruetzleri, Lage & Muricy & Ruiz & Pérez, 2018

Lage, Anaíra, Muricy, Guilherme, Ruiz, César & Pérez, Thierry, 2018, New sciaphilic plakinids (Porifera, Homoscleromorpha) from the Central-Western Pacific, Zootaxa 4466 (1), pp. 8-38 : 25-30

Plakortis ruetzleri sp. nov.

( FIg. 11 , TAbLE 3)

Definition. SMALL, cUSHION-SHAPEd Plakortis WITH dIOdS ANd RARE TRIOdS IN A dISORgANIZEd ARRANgEMENT IN bOTH THE EcTOSOME ANd cHOANOSOME.

Type Material. HOLOTyPE: MNRJ 21833 (MQ32-GR-TP9), cOLLEcTEd IN HATUTU ISLANd, MARqUESAS ISLANdS , FRENcH POLyNESIA (7°54.387'S, 140°07.240’W), IN A LARgE OVERHANg WHIcH cONTINUES IN A dARk UNdERWATER cAVE AT 10 M dEPTH. JANUARy 27, 2012, cOLL. THIERRy PÉREZ . PARATyPE: MNRJ 18462 (MQ32-GR-TP9), SAME dATA Of HOLOTyPE. AddITIONAL MATERIAL: MNRJ 21924, MNRJ 21925, SAME dATA Of TyPE SPEcIMENS.

Description. SPONgE THINLy ENcRUSTINg TO cUSHION-SHAPEd, 0.5–2.0 cM WIdE by 3–5 MM THIck, WITH SLIgHTLy ROUNdEd bORdERS. COLOUR in vivo ANd AfTER fIXATION A gRAdIENT fROM LIgHT bROWN TO A SLIgHTLy dARkER REddISH bROWN ( FIgS. 11A–C ). SURfAcE SMOOTH. OScULES SPARSE, cIRcULAR, WITH A TRANSLUcENT RIM, 0.7–1.1 MM IN dIAMETER. CONSISTENcy RELATIVELy SOfT.

Anatomy. IN TRANSVERSE SEcTIONS, THE cHOANOSOMAL SkELETON IS dISORgANIZEd ANd RELATIVELy dENSE, WITH dIOdS ANd TRIOdS dISPERSEd THROUgHOUT THE cHOANOSOME ( FIg. 11D ). EcTOSOMAL SPEcIALIZATION AbSENT. TANgENTIAL EcTOSOMAL SkELETON dISORgANIZEd, WITH RARE VAgUE TRAcTS Of dIOdS fORMINg AN IRREgULAR RETIcULATION AROUNd THE OVOId PORES, WHIcH MEASURE 30–50 µM IN dIAMETER ( FIg. 11E ). AqUIfEROUS SySTEM LEUcONOId. BOTH EcTOSOMAL ANd bASAL cAVITIES AbSENT.

Spicules ( TAbLE 3). DIOdS AbUNdANT ( FIg. 11F ), VARIAbLE IN SIZE ANd SHAPE. THE SMALLER ARE SLENdER, STRAIgHT, SMOOTH, WITH bLUNT ENdS ANd A cONSPIcUOUS, USUALLy S-bENT cENTRAL IRREgULARITy. THE LARgER dIOdS ARE STOUT, IRREgULAR, SMOOTH, WITH AcERATE ENdS ANd cENTRAL IRREgULARITy MOdERATELy dEVELOPEd, MAINLy cENTROTyLOTE-LIkE. FULL SIZE 30– 110.7–150 / 2.5–5.6–7.5 µM.

TRIOdS RARE, UNIfORM, Y- OR T-SHAPEd, SMOOTH, WITH AcERATE ENdS ( FIg. 11G ). AcTINES 12–40–49 / 1.8–2.5–4.0 µM.

Reproduction. ROUgHLy SPHERIcAL EMbRyOS, 120–360 µM IN dIAMETER, ARE dISPERSEd IN THE cHOANOSOME ( FIg. 11D ).

Ecology. Plakortis ruetzleri sp. nov. LIVES IN SEMI-dARk cAVES IN SyNTOPy WITH Plakinastrella pseudolopha sp. nov. ANd Plakinastrella nicoleae sp. nov. THIS SPONgE WAS cOLLEcTEd AT 10 M dEPTH ON THE ROOf Of A LARgE OVERHANg dOMINATEd by LARgE bLAck cORAL cOLONIES (PÉREZ et al. 2016). NO SIgN Of EPIbIOSIS OR PREdATION WERE ObSERVEd.

Distribution. MARqUESAS ISLANdS, FRENcH POLyNESIA ( FIgS. 1 , 3 ).

Etymology. THE NAME ruetzleri IS gIVEN IN HONOUR Of DR. KLAUS RüTZLER, fOR HIS PIONEERINg STUdIES Of SPONgES fROM SUbMARINE cAVES ANd fOR HIS OUTSTANdINg LONg-TERM cONTRIbUTION TO THE dEVELOPMENT Of SPONgE TAXONOMy.

Taxonomic remarks. THE gENUS Plakortis HAS 29 VALId SPEcIES ANd fEW MORPHOLOgIcAL cHARAcTERS fOR SPEcIES dIScRIMINATION. THE MAIN MORPHOLOgIcAL cHARAcTERISTIcS Of 27 SPEcIES WAS REcENTLy TAbULATEd (UbARE ANd MOHAN 2016), ANd ONLy TWO SPEcIES WERE dEScRIbEd THEREAfTER (VIcENTE et al. 2016). EIgHT SPEcIES ARE dISTINgUISHEd by THE PRESENcE Of MIcRORHAbdS: P. lita dE LAUbENfELS, 1954, P. microrhabdifera MORAES ANd MURIcy, 2003, P. hooperi MURIcy, 2011, P. myrae ERESkOVSky, LAVROV ANd WILLENZ, 2014, P. petrupaulensis DOMINgOS, MORAES ANd MURIcy, 2013, P. spinalis DOMINgOS, MORAES ANd MURIcy, 2013, P. potiguarensis DOMINgOS, MORAES ANd MURIcy, 2013, ANd P. badabaluensis UbARE ANd MOHAN, 2016. ONE SPEcIES HAS qUASIAMPHIASTERS ( P. quasiamphiaster DÍAZ ANd VAN SOEST, 1994). TRIOdS ARE AbSENT IN P. nigra LÉVI, 1953, P. zyggompha dE LAUbENfELS, 1934, ANd P. halichondrioides WILSON, 1902. Plakortis bergquistae MURIcy, 2011 HAS LARgER TRIOdS (30–122 vs. 12–49 µM IN THE NEW SPEcIES) ANd dIOdS (TyPE I 91 –163 µM, TyPE II 202–365 µM vs. 54–126 µM IN P. ruetzleri sp. nov.). FOUR SPEcIES ARE dISTINgUISHEd by THE LARgE SIZE Of dIOdS, UP TO 200 µM OR MORE: P. kenyensis PULITZER-FINALI, 1993; P. angulospiculatus ( CARTER, 1879), P. japonica ( HOSHINO, 1977), ANd P. fromontae MURIcy, 2011. THE REMAININg 12 SPEcIES HAVE dIOdS SHORTER THAN 180 µM ANd TRIOdS UP TO 65 µM (AcTINE LENgTH) LIkE THE NEW SPEcIES. THREE Of THESE HOWEVER HAVE dIOdS IN TWO SIZE cATEgORIES ( P. galapagensis DESqUEyROUX-FAúNdEZ ANd VAN SOEST, 1997, P. edwardsi ERESkOVSky, LAVROV ANd WILLENZ, 2014, ANd P. dariae ERESkOVSky, LAVROV ANd WILLENZ, 2014). IN P. clarionensis ANd P. erythraena LÉVI, 1958 THE dIOdS ARE SHORTER THAN 90 µM. Plakortis albicans CRUZ-BARRAZA ANd CARbALLO, 2005 IS WHITE TO IVORy, WITH THIN SURfAcE cANALS. TWO SPEcIES, P. deweerdtaephila VIcENTE, ZEA ANd HILL, 2016 ANd P. symbiotica VIcENTE, ZEA ANd HILL, 2016 HAVE ObLIgATORy ASSOcIATIONS WITH HAPLOScLERId SPONgES.

Plakortis ruetzleri sp. nov. IS MOST SIMILAR TO THE REMAININg fOUR SPEcIES Of THE simplex SPEcIES gROUP, WITH bROWN cOLOUR, dIOdS, TRIOdS, ANd WITHOUT MIcRORHAbdS. Plakortis simplex ScHULZE, 1880 cAN bE bROWN, WHITE, yELLOW OR TAN, ANd HAS bOTH EcTOSOMAL ANd bASAL cAVITIES WHIcH ARE LAckINg IN THE NEW SPEcIES. Plakortis insularis MORAES ANd MURIcy, 2003 IS cHOcOLATE TO LIgHT bROWN, RELEASES A dARk EXUdATE WITH STRONg TERPENOId SMELL IN ETHANOL, HAS A fRAgILE cONSISTENcy, EcTOSOME WITH PIgMENTEd cELLS, ANd LOW SPIcULE dENSITy. Plakortis copiosa PULITZER-FINALI, 1993 IS gREy OR bROWN OUTSIdE ANd cREAM INSIdE, WITH HARd OR fRAgILE cONSISTENcy, ANd HAVE PARTIcULARLy SyMMETRIcAL TRIOdS. Plakortis communis MURIcy, 2011 IS gREyISH-bROWN TO bLAck, HAS A TANgENTIAL EcTOSOMAL RETIcULATION WITH cIRcULAR MESHES, ANd A PARTLy ALVEOLAR cHOANOSOMAL SkELETON. THE NEW SPEcIES THEREfORE dIffERS fROM ALL OTHER Plakortis SPEcIES by A UNIqUE cOMbINATION Of cHARAcTERS: bROWN cOLOUR, dISORgANIZEd SkELETON, PRESENcE Of dIOdS ANd TRIOdS, ASyMMETRIcAL SHAPE Of TRIOdS, ANd THE AbSENcE Of MIcRORHAbdS, bASAL ANd EcTOSOMAL cAVITIES, dARk EXUdATES, ANd Of TERPENOId SMELL.

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GBR, Great Barrier Reef. *, type localities. **, identification probably inaccurate, records needs revision.

Figures

FIGURE 1. Location of collection sites. A, Pacific Ocean showing New Caledonia and Marquesas Islands. B, Marquesas Islands showing Nuku Hiva and Hatutu Island (red circles). C, New Caledonia showing Bourail and Hienghène (red circles)

FIGURE 3. Distribution of Homoscleromorpha species in the Pacific Ocean. Records identified only to genus level (as sp., cf., or aff.) and from Antarctica were not included. See Table 4 for locality names and references

FIGURE 11. Plakortis ruetzleri sp. nov. A, specimens in situ. B, holotype MNRJ 21833 after fixation. C, paratype MNRJ 18462 after fixation. D, transversal section showing the disorganized choanosomal skeleton, the undifferentiated ectosomal skeleton and one embryo. E, tangential section showing the disorganized ectosomal skeleton and elliptical pores. F, diods. G, triods (F–G, SEM). Key: em, embryo; p, pores.