Phialoba steinbecki Carlgren, 1951

Barragán, Yamaly, Sánchez, Carlos & Rodríguez, Estefanía, 2019, First inventory of sea anemones (Cnidaria: Actiniaria) from La Paz Bay, southern Gulf of California (Mexico), Zootaxa 4559 (3), pp. 501-549 : 527-530

Phialoba steinbecki Carlgren, 1951

( FIgS. 2 , 15–17 , TAble 7)

Phialoba steinbecki Carlgren, 1949 (nomen nudum)

(?) Phialoba steinbecki Carlgren, 1949 : Acuña et al. (2013)

Phialoba steinbecki Carlgren, 1951

Material eXamined. (See TAble 2).

Description. EXTeRNAl ANATOmY ( FIg. 15 ): Well deVelOped pedAl dISC, TO 22 mm dIAmeTeR IN pReSeRVed SpeCImeNS. COlUmN CYlINdRICAl, SmOOTh, TO 18 mm heIghT ANd TO 23 mm dIAmeTeR IN pReSeRVed SpeCImeNS. NO fOSSe. FUllY eXpANded ORAl dISC ANd TeNTACleS TO 33 mm dIAmeTeR, ORAl dISC WIde, TO 27 mm dIAmeTeR IN pReSeRVed SpeCImeNS. Up TO 384 TeNTACleS, ReSTRICTed TO mARgIN Of ORAl dISC, heXAmeROUSlY ARRANged IN SeVeN CYCleS, TO SIX mm leNgTh IN pReSeRVed SpeCImeNS, SImple, ShORT, STICkY, SmOOTh, All Of SImIlAR leNgTh. ONe OR TWO SmAll ROUNd pROTUbeRANCeS IN The ORAl dISC ARRANged RAdIAllY COINCIdINg WITh The eNdOCOelS Of fIRST CYCleS Of TeNTACleS ( FIg. 14D, F ). MeSeNTeRIAl INSeRTIONS VISIble IN pedAl dISC ANd ORAl dISC.

INTeRNAl ANATOmY ANd mICROANATOmY ( FIg. 16 ): MeSeNTeRIeS heXAmeROUSlY ARRANged IN fIVe CYCleS AT leVel Of ACTINOphARYNX: fIRST TO ThIRd CYCleS peRfeCT; fOURTh ANd fIfTh ImpeRfeCT. FIRST TO fOURTh CYCleS feRTIle, eXCepT dIReCTIVeS. GONOChORIC, OOCYTeS 0.04–0.4 mm IN dIAmeTeR IN SpeCImeNS COlleCTed IN MAY. MORe meSeNTeRIeS dISTAllY ThAN pROXImAllY (SIXTh CYCle ONlY dISTAllY). TWO Well deVelOped SIphONOglYphS ATTAChed TO TWO pAIR Of dIReCTIVe meSeNTeRIeS. ReTRACTOR mUSCleS STRONg ANd dIffUSe TO ReSTRICTed, OCCUpYINg hAlf-leNgTh Of meSeNTeRIeS. PARIeTObASIlAR mUSCleS WITh WeAk ANd ThIN fRee meSOgleAl lAmellA. BASIlAR mUSCleS Well deVelOped, WITh ShORT ANd ThIN meSOgleAl pROCeSSeS. NO mARgINAl SphINCTeR mUSCle. LONgITUdINAl mUSCleS Of TeNTACleS ANd ORAl dISC eCTOdeRmAl. ZOOXANThellAe pReSeNT.

COlOR ( FIg. 15 ): IN lIVINg SpeCImeNS pedAl dISC WhITe. COlUmN lIghT bROWN WITh dARk bROWN mARgIN. ORAl dISC beIge OR WhITe WITh bROWN RAdIAl lINeS. MOUTh bROWN, hYpOSTOme bROWN OR gReeN. TeNTACleS beIge OR lIghT bROWN WITh gReeN OR pURple TIpS; WITh WhITe ANNUlAR bANdS ANd WhITe dOTS ON The ORAl SIde. PReSeRVed SpeCImeN beIge.

CNIdOm ( FIg. 17 ): BASITRIChS, p -mASTIgOphOReS A, ANd SpIROCYSTS. See TAble 7 fOR SIZe ANd dISTRIbUTION.

Geographic and bathymetric distribution. Phialoba steinbecki IS fOUNd ONlY IN The MeXICAN PACIfIC. CARlgReN (1951) RepORTed IT IN CORONAdO ISlANd, PUeRTO ESCONdIdO ANd IN The eAST Of LA PAZ. ThIS IS The fIRST RepORT IN LA CONChA, CAImANCITO, CAleRITAS, ROfOmeX, CAjeTe ANd PUNTA COYOTe (NORTh 2) ( FIg. 1 ), IN The INTeRTIdAl beTWeeN 0–5 meTeRS.

Remarks. Phialoba steinbecki IS The ONlY SpeCIeS IN The geNUS. ThIS IS The fIRST Re-deSCRIpTION bASed ON NeWlY COlleCTed mATeRIAl SINCe The ORIgINAl deSCRIpTION. In vivo SpeCImeNS, eXTeRNAl ANd INTeRNAl ANATOmY, ANd CNIdOm ARe IllUSTRATed heRe fOR The fIRST TIme. ACUñA et al. (2013) RepORTed ThIS SpeCIeS IN The CARIbbeAN COAST Of COSTA RICA bUT The AUThORS dId NOT pROVIde ANY deSCRIpTION, ImAgeS Of ANATOmY OR CNIdAe. FURTheRmORe, TheSe AUThORS ASSIgNed AN INCORReCT dATe IN The AUThORShIp INfORmATION Of The SpeCIeS (See SYNONYmY lIST AbOVe). BeCAUSe ThIS SpeCIeS hAS beeN SO fAR ONlY RepORTed IN The PACIfIC OCeAN, We dO NOT CONSIdeR The RepORT fROm ACUñA et al. (2013) RelIAble UNTIl SOme dATA Of TheIR SpeCImeNS ARe pROVIded; We INClUded ThIS ReCORd IN The SYNONYmY lIST WITh A qUeSTION mARk beCAUSe IS ImpORTANT TO NOTe dUbIOUS ReCORdS. The eXTeRNAl ANd INTeRNAl feATUReS Of The STUdIed mATeRIAl AgRee Well WITh The ORIgINAl deSCRIpTION bY CARlgReN (1951). HOWeVeR, We dId NOT fINd The mARgINAl SpheRUleS meNTIONed bY CARlgReN (1951). We ONlY fOUNd TWO SmAll pROjeCTIONS IN The mOST dISTAl COlUmN (See FIg. 15C ). IN AddITION, We fOUNd SlIghT dIffeReNCeS IN The CNIdAe ( TAble 7). We fOUNd p -mASTIgOphOReS A ANd AbUNdANT SpIROCYSTS IN The TeNTACleS ThAT CARlgReN (1951) OmITTed IN hIS deSCRIpTION. BeCAUSe The lACk Of SpIROCYSTS IN The TeNTACleS WIThIN ACTINIARIA IS RATheR UNCOmmON ( STepheNSON 1928), We CONSIdeR ThAT CARlgReN (1951) mOST pRObAblY OVeRlOOked TheSe CNIdAe CATegORIeS. AlSO, The bASITRIChS IN The COlUmN RepORTed bY CARlgReN (1951) ARe lARgeR bASITRIChS ThAN ThOSe ThAT We fOUNd. FINAllY, We NOTICed IN All The SpeCImeNS eXAmINed SmAll ROUNded pROTUbeRANCeS RAdIAllY ARRANged ANd COINCIdINg WITh The eNdOCOelS Of The fIRST CYCleS Of TeNTACleS IN The ORAl dISC ( FIg. 15D, F ). TheSe STRUCTUReS ReSemble The dISCAl TeNTACleS Of Phymanthus MIlNe-EdWARdS & HAIme, 1851, A geNUS RelATIVelY SImIlAR eXTeRNAllY TO Phialoba , eXCepT fOR hAVINg VeRRUCAe IN The COlUmN (WhICh IS SmOOTh IN Phialoba ) ANd dISCAl TeNTACleS. The pReSeNCe Of mARgINAl SpheRUleS ANd Of pUTATIVelY dISCAl TeNTACleS IN P. steinbecki , AS Well AS The pOTeNTIAl ClOSe RelATIONShIp Of Phialoba ANd Phymanthus RemAINS UNCeRTAIN UNTIl The TYpe mATeRIAl Of P. steinbecki IS ReeXAmINed. IN LA PAZ BAY, P. steinbecki IS VeRY COmmON; IT IS fOUNd ATTAChed TO deAd CORAl, ROCkS ANd beTWeeN CReVICeS. We CONSIdeRed IT TO be AN eNdemIC SpeCIeS fROm BAjA CAlIfORNIA SUR (LA PAZ BAY TO LOReTO) UNTIl SpeCImeNS RepORTed bY ACUñA et al. (2013) ARe ReCONSIdeRed.

Figures

FIGURE 1. Map of the localities where studied species were collected. Numbers correspond with sampling localities in Table 2.

FIGURE 2. Living specimens of A) Anthopleura dowii. B) Bunodosoma californicum. C) Bunodosoma grande. D) Isoaulactinia hespervolita. E) Phymactis papillosa. F) Phialoba steinbecki. G) Alicia beebei. H) Calliactis polypus.

FIGURE 14. Cnidae of Isoaulactinia hespervolita Daly, 2004. A, B, D, F, G, H, L, M, O, P) Basitrichs. I) Holotrich. J) p- mastigophore A with looped basal tubule. Q) b-mastigophore. E, K, N, R) p-mastigophores A. S) p-mastigophore B2a. C) Spirocyst.

FIGURE 15. External anatomy of Phialoba steinbecki Carlgren, 1951. A) Lateral view of preserved specimen. B) Oral view of living specimen. C) Detail of small projection in distal column (black circle). D) Detail of small rounded protuberance in oral disc (black circle). E–F) Oral view of specimens in vivo, showing the small rounded protuberances in oral disc (circles). Oral disc (Od), Margin (Ma). Scale bars: 5 mm.

FIGURE 16. Internal anatomy of Phialoba steinbecki Carlgren, 1951. A) Longitudinal section of the distal column. B) Cross section of the column at the level of the actinopharynx showing the cycles of mesenteries (cycles marked by numbers). C) Cross section through a tentacle showing ectodermal longitudinal musculature. D) Cross section of column showing gametogenic tissue. E) Longitudinal section of proximal end showing basilar muscles. F) Detail of a cross section of the column at the level of the actinopharynx showing the retractor and parietobasilar muscles. Basilar muscles (Ba), Ectoderm (Ec), Endoderm (En), Mesoglea (Me), Oocytes (O), Parietobasilar muscles (Pa), Retractor muscles (Re), Siphonoglyphs (arrows), Tentacle (Te). Scale bars: A, C–F, 0.1 mm; B, 0.5 mm.

FIGURE 17. Cnidae of Phialoba steinbecki Carlgren, 1951. A, D, E, F, H, I) Basitrichs. C, G, J) p-mastigophores A. B) Spirocyst.