Hemimycale oxeata, Huguenin & Salani & Lopes & Albano & Hajdu & Esteves, 2018

Huguenin, Larissa, Salani, Sula, Lopes, Maira F., Albano, Rodolpho M., Hajdu, Eduardo & Esteves, Eduardo Leal, 2018, Integrative taxonomy of Hemimycale (Hymedesmiidae: Poecilosclerida: Demospongiae) from Southeastern Brazil, with the description of two new species, Zootaxa 4442 (1), pp. 137-152 : 140-143

Hemimycale oxeata sp. nov.

( FIgURES 2 , 3 ; TAbLES 1, 3)

Synonymy: Hemimycale Sp., Muricy et al., 1991: 5 .

Diagnosis. ThIS IS ThE ONLY SPEcIES IN ThE gENUS wITh OXEOTE LIkE TORNOTE mEgAScLERES IN AddITION TO ThE TYPIcAL (SUbTYLO-)STRONgYLES. MIcROScLERES AbSENT.

Material examined. Holotype MNRJ 21302 , GURIRI ISLET (23° 10’ 24.21”S, 44° 05’ 32.54”W), OFF ILhA GRANdE, ANgRA dOS REIS, SOUThERN RIO dE JANEIRO STATE, 10 m dEPTh, cOLL. E. L . ESTEVES, APRIL 5, 2013; SLIdES OF cROSS SEcTIONS ANd dISSOcIATEd SPIcULES FROm ThE hOLOTYPE ARE dEPOSITEd UNdER UERJPOR 85. Paratypes: MNRJ 276, ITAçUcê ISLET (23° 49’ 54.06”S, 45° 26’ 36.04”W, BAREqUEçAbA bEAch), SãO SEbASTIãO, SãO PAULO STATE, 6 m dEPTh, cOLL. E. HAjdU, JANUARY 23, 1996 ; MNRJ 3989, FORNO hARbOUR (22° 58’ 12”S, 42° 00’ 36” W), ARRAIAL dO CAbO, RIO dE JANEIRO STATE, 4‒8 m dEPTh, cOLLS. E. HAjdU & E . VILLANOVA, APRIL 11, 2001; MNRJ 14651, ARVOREdO ISLANd (27° 17’ 00”S, 48° 22’ 00”W), OFF BOmbINhAS, SANTA CATARINA, 15 m dEPTh, cOLL. C. PAScELLI, JANUARY 29, 2013 ; MNRJ 15582, ALcATRAzES ARchIPELAgO (24° 06.333’S, 45° 42.127’W), OFF SãO SEbASTIãO, SãO PAULO STATE, 8.5 m dEPTh, cOLL. S. SALANI & E. HAjdU, JULY 28, 2012 ; MNRJ 15590, ALcATRAzES ARchIPELAgO (24° 05’ 44.6”S, 45° 41’ 32.4”W), OFF SãO SEbASTIãO, SãO PAULO STATE, 10.4 m dEPTh, cOLLS. S. SALANI & E. HAjdU, JULY 29, 2012 ; UERJPOR 105 ANd 110 (SAmE dATA AS FOR ThE hOLOTYPE).

Etymology. ThE NAmE “ oxeata ” IS A REmINdER OF ThE PRESENcE OF OXEAS IN ThE NEw SPEcIES.

Description. ThINLY TO ThIckLY ENcRUSTINg (4.5‒8.7 cm wIdE, 0.8‒3.0 mm ThIck). ORANgE cOLOR IN LIFE, EXTERNALLY ANd INTERNALLY, ANd bEIgE AFTER FIXATION IN EThANOL. EcTOSOmE LIghTER cOLOREd ThAN ThE chOANOSOmE. OScULES cIRcULAR, wITh A PRONOUNcEd PERIOScULAR mEmbRANE (1.2‒3.7 mm wIdE). SUbdERmAL chANNELS cONSPIcUOUS (0.2‒0.7 mm wIdE), cONFLUENT TO OScULES. AREOLATEd PORE SIEVES cIRcULAR TO IRREgULAR, LARgE (1.6‒12 mm wIdE), wITh A SLIghTLY ELEVATEd RIm (1 mm hIgh), cONSPIcUOUS ANd cLOSELY SPAcEd ON ThE SURFAcE. SURFAcE EVEN, SmOOTh. CONSISTENcY SOFT, ELASTIc ANd FRIAbLE.

INTERNAL ANATOmY: EcTOSOmAL SkELETON UNdIFFERENTIATEd FROm ThE chOANOSOmE. AREOLATEd PORE SIEVES STRENgThENEd bY EVENLY SPAcEd (79‒170 µm), PERPENdIcULARLY ARRANgEd, dENSE chOANOSOmAL mULTISPIcULAR TRAcTS OF (SUbTYLO-)STRONgYLES, SPLITTINg OUT IN FAN ShAPEd TUFTS SUPPORTINg ThE AREOLAE wALL. CRIbRIPORAL mEmbRANE 11 ‒ 12 µm ThIck. SUbEcTOSOmAL LAcUNAE EVIdENT (78 ‒ 291 µm wIdE). ChOANOSOmAL SkELETON PLUmOSE, cOmPOSEd bY SINUOUS, AScENdINg, mULTISPIcULAR TRAcTS OF STRONgYLES ANd OXEAS (11‒18 SPIcULES wIdE, UP TO 58 µm ThIck) ENdINg IN SUbEcTOSOmAL TUFTS OF STRONgYLES, SOmETImES wITh POINTS PROjEcTEd bEYONd ThE EcTOSOmE ON ThE SURFAcE. ISOLATEd STRONgYLES ANd OXEAS ALSO cOmmONLY FOUNd ScATTEREd IN ThE INNER PARTS OF ThE chOANOSOmE.

SPIcULES ( TAbLES 1, 3): MEgAScLERES, STRONgYLES VARYINg TO SUbTYLOTES OR SUbTYLOSTRONgYLES, SmOOTh, STRAIghT, SLIghTLY cURVEd OR SINUOUS ( FIg. 3E‒F ); OXEAS SmOOTh, STRAIgTh, wITh mUcRONATE OR TELEScOPEd ENdS ( FIg. 3G‒H ). MIcROScLERES AbSENT.

Ecology. Hemimycale oxeata sp. nov. OccURS IN ShALLOw wATERS (dOwN TO 19 m dEEP), ENcRUSTINg VERTIcAL ROckY wALLS, EXPOSEd TO hIgh SPEEd cURRENTS, OR IN ScIOPhILOUS hAbITATS. COLLEcTEd SPEcImENS wERE OVERgROwINg ROdOLIThS, mUSSELS, bARNAcLES ANd AzOOXANThELATE hARd cORALS. POLYchAETE wORmS cAN bE ASSOcIATEd wITh ThE NEw SPEcIES.

Distribution. ( FIg. 1 ) SOUThEASTERN BRAzIL EcOREgION: RIO dE JANEIRO (MURIcY et al., 1991 AS Hemimycale SP. ), SãO PAULO ANd SANTA CATARINA STATES (FIRST REcORd IN ThE PRESENT STUdY).

Remarks. Hemimycale oxeata sp. nov. IS ThE ONLY SPEcIES IN ThE gENUS wITh OXEAS IN AddITION TO (SUbTYLO-)STRONgYLES AS mEgAScLERES. ThE OXEAS EXhIbITEd bY ThE NEw SPEcIES ARE AcTUALLY OXEOTE-LIkE TORNOTES, PRObAbLY dERIVEd FROm STRONgYLES, wITh TELEScOPEd OR mUcRONATE ENdS, ANd A STRAIghT AXIS.

Hemimycale oxeata sp. nov. IS SImILAR TO H. columella ANd H. insularis . ThEY ShARE A SALmON ORANgE cOLOR IN LIFE, A ThINLY ENcRUSTINg gROwTh FORm, ANd IRREgULARLY OUTLINEd, SLIghTLY RAISEd PORE SIEVES. ThIS IS PARTIcULARLY SO wITh ThE LATTER SPEcIES (FIg PAgES 138‒139; MORAES, 2011). HOwEVER, IN AddITION TO ThE PRESENcE OF EXcLUSIVE OXEAS, H. oxeata sp. nov. hAS SmALLER (SUbTYLO-)STRONgYLES ThAN ThOSE ObSERVEd IN H. columella ANd H. insularis ( TAbLE 3), ANd STYLES ARE ENTIRELY AbSENT (PRESENT IN H. columella ; BOwERbANk, 1874 AS Desmacidon columella ; VAcELET et al., 1987; VAN SOEST, 2002A; URIz et al., 2017).

AddITIONAL SPEcIES IN Hemimycale ARE ALSO cLEARLY dIFFERENT FROm ThE NEw SPEcIES. Hemimycale arabica IS dARk gREENISh-bLUE whEN ALIVE, hAS ShORTER ANd ThINNER STRONgYLES ( TAbLE 3), ANd SImILARLY TO H. columella mAY hAVE STYLES IN AddITION TO STRONgYLES AS mEgAScLERES (ILAN et al., 2004), whIch ARE cOmPLETELY AbSENT IN ThE NEw SPEcIES. Hemimycale rhodus cAN bE dIFFERENTIATEd FROm H. oxeata sp. nov. bY ITS LONgER (SUbTYLO-)STRONgYLES ( TAbLE 3). Hemimycale mediterranea hAS A bROwNISh cOLOR dUE TO ITS ASSOcIATION wITh cYANObAcTERIA (URIz et al., 2017), ANd hIghER ANd NARROwER PORE SIEVES (1.5‒2 mm hIgh; 3 mm wIdE). IN AddITION, ThEIR STRONgYLES SEEm TO POSSESS mORE REgULAR ENdINgS ( FIg. 4A‒E ; URIz et al., 2017) ThAN ThOSE OF ThE NEw SPEcIES, whIch FREqUENTLY VARY TO SUbTYLOTES OR SUbTYLOSTRONgYLES ( FIg. 3E‒F ).

HENcE, H. oxeata sp. nov. cAN bE cLEARLY SET APART FROm OThER SPEcIES IN ThE gENUS bY ITS SALmON ORANgE cOLOR IN LIFE, ANd OXEOTE-LIkE TORNOTES IN AddITION TO ThE TYPIcAL (SUbTYLO-)STRONgYLES OFTEN SEEN IN ThE gENUS. SPEcImENS IdENTIFIEd bY MURIcY et al. (1991) AS Hemimycale SP. FROm ARRAIAL dO CAbO (RIO dE JANEIRO STATE) bELONg TO ThIS NEw SPEcIES.

Figures

FIGURE 1. DiStribution of Hemimycale Spp. in the SoutheaStern Brazil Ecoregion (A) Map of South America With SoutheaStern Brazil Ecoregion and Sampling areaS in detail; (B) Arraial do Cabo and Cabo Frio iSland; (C) Ilha Grande; (D) São SebaStião and Ilhabela; (E) AlcatrazeS Archipelago; (F) Arvoredo iSland. (*) Hemimycale oxeata sp. nov.; (•) Hemimycale ceadensis sp. nov.

FIGURE 2. In situ photographS of Hemimycale neW SpecieS from SoutheaStern Brazil Ecoregion. (A‒B) Hemimycale oxeata sp. nov. from Guriri iSlet: (A) Paratype UERJPOR 110; (B) Surface of the Paratype UERJPOR 105 in detail; (C‒D) Hemimycale ceadensis sp. nov. from Jorge Grego ISland: (C) Holotype 21303 (D) Surface of the Paratype UERJPOR 188 in detail.

FIGURE 3. Hemimycale oxeata sp. nov., fixed Specimen, Skeleton and SpiculeS; (A) Paratype UERJPOR 110; (B) CloSe up of a pore Sieve of the Paratype MNRJ 276; (C) CroSS Section of Skeleton obtained from a paraffin embedded fragment of a Specimen; (D) CroSS Section of Skeleton obtained With a diamond SaW from an epoxy reSin embedded Specimen (the arroW point to the Skeleton of a pore Sieve); (E‒H) SEM imageS of SpiculeS: (E) StrongyleS varying to SubtyloteS or SubtyloStrongyleS; (F) ExtremitieS of (Subtylo-)StrongyleS in detail; (G) OxeaS; (H) Mucronate and teleScoped endS of oxeaS in detail.

FIGURE 4. Hemimycale ceadensis sp. nov., fixed Specimen, Skeleton and SpiculeS; (A) Paratype 203; (B) CloSe up of a pore Sieve of the Holotype MNRJ 21303; (C) CroSS-Section of Skeleton obtained from a parafin embeded Specimen (the arroW point to the Skeleton of a pore Sieve); (D) Tangential Section of the Skeleton ShoWing the choanoSomal aScending tractS of (Subtylo-)StrongyleS ending in SubectoSomal tuftS next to the Surface (the arroWS point to the Skeleton of pore SieveS); (E‒F), SEM imageS of SpiculeS: (E) StrongyleS varying to aniSoStrongyleS or SubtyloStrongyleS; (F) ExtremitieS of (Subtylo-)StrongyleS in detail.