Anthopleura dowii Verrill, 1869

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 : 503-512

Anthopleura dowii Verrill, 1869

( FIgS. 2–5 , TAble 3)

Anthopleura Dowii [sic] Verrill, 1869

Anthopleura Dovii [sic] Verrill: Andres 1883

Anthopleura dowii Verrill, 1869 : Carlgren 1949

Anthopleura sp.: Francis 1988

Bunodactis mexicana Carlgren, 1949 (nomen nudum)

Bunodactis mexicana Carlgren, 1951

Material eXamined. (See TAble 2).

Description. EXTeRNAl ANATOmY ( FIg. 3 ): Well deVelOped pedAl dISC, TO 21 mm dIAmeTeR IN pReSeRVed SpeCImeNS. COlUmN CYlINdRICAl, TO 17 mm heIghT ANd 18 mm dIAmeTeR IN pReSeRVed SpeCImeNS, WITh lONgITUdINAl ROWS Of VeRRUCAe fROm dISTAl mARgIN TO pedAl dISC. EACh eNdOCOelIC mARgINAl pROjeCTION WITh AN ACRORhAgUS WITh hOlOTRIChS ANd bASITRIChS. Deep fOSSe. FUllY eXpANded ORAl dISC ANd TeNTACleS TO 38 mm dIAmeTeR, ORAl dISC TO 22 mm dIAmeTeR

IN pReSeRVed SpeCImeNS. Up TO 134 TeNTACleS, heXAmeROUSlY ARRANged IN SIX CYCleS, TO 5 mm leNgTh IN pReSeRVed SpeCImeNS, SImple, STICkY, SmOOTh, All Of SImIlAR leNgTh. MeSeNTeRIAl INSeRTIONS VISIble IN pedAl dISC ANd ORAl dISC.

INTeRNAl ANATOmY ANd mICROANATOmY ( FIg. 4 ): MeSeNTeRIeS heXAmeROUSlY ARRANged IN fIVe CYCleS: fIRST TO fOURTh CYCleS peRfeCT; fIfTh ImpeRfeCT. PeRfeCT meSeNTeRIeS INClUdINg dIReCTIVeS feRTIle. GONOChORIC, SpeRmATIC CYSTS 0.05– 0.08 mm IN dIAmeTeR IN SpeCImeNS COlleCTed IN AUgUST. TWO SIphONOglYphS ATTAChed TO TWO dIReCTIVe meSeNTeRIeS. SAme NUmbeR Of meSeNTeRIeS dISTAllY ANd pROXImAllY. ReTRACTOR mUSCleS STRONg ANd ReSTRICTed, OCCUpYINg hAlf- leNgTh Of meSeNTeRIeS. PARIeTObASIlAR mUSCleS WITh WeAk ANd ThIN fRee meSOgleAl lAmellA. BASIlAR mUSCleS Well deVelOped, WITh lONg ANd ThIN meSOgleAl pROCeSSeS. MARgINAl SphINCTeR mUSCle CIRCUmSCRIbed ANd pedUNCUlATed. LONgITUdINAl mUSCleS Of TeNTACleS ANd ORAl dISC eCTOdeRmAl.

COlOR ( FIg. 3 ): IN lIVINg SpeCImeNS, pedAl dISC ANd COlUmN OlIVe OR bROWN. VeRRUCAe ANd ACRORhAgI WhITISh. ORAl dISC gReeN, ORANge OR pINk AROUNd mOUTh; WITh ORANge, bROWN, gReY OR pURple RAdIAl lINeS fROm The bASe Of The TeNTACleS TO mOUTh. TeNTACleS gReY, pURple OR ORANge, WITh A dARk lONgITUdINAl STRIpe ANd ORANge SpOTS AlONg The TeNTACle IN ORAl SIde.

CNIdOm ( FIg. 5 ): BASITRIChS, b -mASTIgOphOReS, hOlOTRIChS, p -mASTIgOphOReS A ANd B1, ANd SpIROCYSTS. See TAble 3 fOR SIZe ANd dISTRIbUTION.

Geographic and bathymetric distribution. Anthopleura dowii IS fOUNd AlONg The PACIfIC OCeAN fROm PANAmA TO MeXICO (FAUTIN 2013). IN The MeXICAN PACIfIC, IT IS RepORTed IN CeRRITOS, TeCOlOTe, PUeRTO ESCONdIdO, SAN CARlOS BAY ANd LOS ANgeleS BAY ( CARlgReN 1951; DAlY 2004). ONlY VeRRIll (1869) meNTIONed The depTh (0 meTeRS). ThIS IS The fIRST ReCORd fOR CAleRITAS, AT 0–1 meTeR.

Remarks. Of The CURReNTlY VAlId 48 SpeCIeS Of Anthopleura ACCORdINg TO DAlY & FAUTIN (2018), ThRee SpeCIeS, A. dowii , A. elegantissima ( BRANdT, 1835) ANd A. sola PeARSe & FRANCIS, 2000, ARe RepORTed IN The MeXICAN PACIfIC. TORReY (1906) SYNONYmIZed A. dowii WITh A. xanthogrammica ( BRANdT, 1835) beCAUSe Of The SImIlARITIeS IN The eXTeRNAl ANATOmY. HOWeVeR, HANd (1955) dIffeReNTIATed bOTh SpeCIeS bASed ON The SIZeS RANgeS Of The CNIdAe ANd pROpOSed The CNIdOm AS The beST WAY TO dISTINgUISh The SpeCIeS WIThIN ThIS geNUS. Anthopleura dowii lACkS SpIROCYSTS IN The ACRORhAgI ANd The hOlOTRIChS IN The ACRORhAgI (CITed AS ATRIChS IN HANd (1955)) ARe ShORTeR ThAN ThOSe IN A. elegantissima . IN AddITION, The bASITRIChS II ANd The p -mASTIgOphOReS A Of The fIlAmeNTS Of A. dowii ARe ShORTeR ThAN ThOSe IN A. elegantissima ( TAble 2). The feATUReS Of The STUdIed mATeRIAl AgRee Well WITh The pReVIOUS deSCRIpTIONS Of A. dowii (e.g. DAlY 2004). SImIlARlY, TO DAlY (2004, FIg. 3A ), We fINd ThAT The mARgINAl SphINCTeR mUSCle IS pedUNCUlATe IN A. dowii . AlThOUgh We fOUNd SlIghT dIffeReNCeS IN The SIZeS RANgeS Of SOme NemATOCYSTS (e.g. bASITRIChS II IN The COlUmN ANd b -mASTIgOphOReS IN The fIlAmeNTS ARe lARgeR IN DAlY (2004) ThAN IN The pReSeNT STUdY), We ATTRIbUTe Them TO INTRASpeCIfIC VARIATION. IN AddITION, We fINd The NemATOCYST IN The fIlAmeNT NAmed AS mICRObASIC b -mASTIgOphORe bY DAlY (2004, See fIg. 5K) TO be A p -mASTIgOphORe B1 ( FIg. 5R ). ThIS TYpe Of NemATOCYST IS RARelY fOUNd WIThIN ACTINIOIdeAN SeA ANemONeS ( SChmIdT 1972, 1974). IN LA PAZ BAY A. dowii ReSembleS Bunodosoma californicum CARlgReN, 1951 , B. grande , ANd Isoaulactinia hespervolita DAlY, 2004 dUe TO The pROTUbeRANCeS IN The COlUmN, The NUmbeR Of TeNTACleS, ANd hAbITAT. HOWeVeR, The pReSeNCe Of VeRRUCAe IN The COlUmN Of A. dowii INSTeAd Of VeSICleS dISTINgUISheS IT fROm B. californicum ANd B. grande ; The pReSeNCe Of ACRORhAgI IN A. dowii dISTINgUISheS IT fROm I. hespervolita , WhICh lACkS TheSe mARgINAl pROjeCTIONS ( CARlgReN 1951; DAlY 2004).

Figures

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 3. External anatomy of Anthopleura dowii Verrill, 1869. A–D) Oral view of living specimen. E) Detail of acrorhagi. F) Detail of tentacles. Acrorhagi (Ac), Oral disc (Od), Verrucae (Ve).

FIGURE 4. Internal anatomy of Anthopleura dowii Verrill, 1869. A) Longitudinal section of the distal column showing marginal sphincter muscle and column specializations. B) Cross section of the column at the level of the actinopharynx showing the cycles of mesenteries (cycles marked by numbers). C) Cross section of column showing gametogenic tissue. D) Longitudinal section of proximal end showing basilar muscles. E) Detail of a cross section of the gametogenic tissue. F) Detail of a cross section of the column at the level of the actinopharynx showing the retractor and parietobasilar muscles. Acrorhagi (Ac), Basilar muscles (Ba), Fosse (Fo), Marginal projections (Mp), Parietobasilar muscles (Pa), Peduncle (Pe), Retractor muscles (Re). Siphonoglyphs (arrow). Spermatic cyst (Sc), Sphincter (Sp), Tentacle (Te), Verrucae (Ve). Scale bars: A, C–F, 0.1 mm; B, 0.5 mm.

FIGURE 5. Cnidae of Anthopleura dowii Verrill, 1869. A, B, D, E, H, I, K, L, N, O) Basitrichs. F, G, J) Holotrichs. P, Q) b- mastigophores. M) p-mastigophore A. R) p-mastigophore B1. C) Spirocyst.