Clytia cf. gracilis (M. Sars, 1850)

Humara-Gil, Karla J. & Cruz-Gómez, Christopher, 2018, New records of benthic hydroids (Cnidaria: Hydrozoa) from the coast of Oaxaca, Mexico, Zootaxa 4455 (3), pp. 454-470 : 458-461

Clytia cf. gracilis (M. Sars, 1850)

FIg. 4

Laomedea gracilis M. SARS, 1850: 138.

Clytia gracilis .—CALdER, 1991: 54, fIG. 31 (SyN.).— SchuchERt, 2001: 151, fIG. 131 (SyN.).— SchuchERt, 2003: 164, fIG. 23 (SyN.).—LINdNER et al., 2011: 23.— CuNhA et al., 2017: 118.

Type locality of the nominal species. LOfOTEN ISLANdS, NORWAY ( SchUchERT 2003).

Material examined. TWO cOLONIES: UMAR-HYDR-005, ONE cOLONY ON ROcKS (ChAcAhUA BAY, OAXAcA, 15°57’56’’N 97°40’37’’W, 2 m, 13 NOVEmbER 2014, cOLL. S. VIchIdO-MEdINA); UMAR-HYDR-006, ONE cOLONY ON ROcKS (ChAcAhUA BAY, OAXAcA, 15°57’56’’N 97°40’37’’W, 1.5 m, 13 NOVEmbER 2014, cOLL. J. DíAZ-RAmOS).

Description. COLONIES EREcT, 2.2–3.0 mm hIgh, ARISINg fROm A cREEPINg hYdRORhIZA. HYdROcAULUS mONOSIPhONIc, bRANchEd OR UNbRANchEd. PERISARc Of AVERAgE ThIcKNESS, WITh VARIAbLE ANNULATIONS PROXImALLY ANd dISTALLY; ANNULATIONS ALSO SOmETImES PRESENT ON mIddLE Of STEm. HYdROThEcAE cAmPANULATE, AbOUT 500 µm LONg, 350 µm WIdE AT mARgIN. HYdROThEcAL mARgIN WITh 12 SLIghTLY TILTEd cUSPS. GONOThEcAE cYLINdRIcAL, 700–750 µm LONg, 350 µm WIdE AT ORIfIcE; WALLS SmOOTh; APERTURE TRUNcATEd, TERmINAL; ARISINg fROm STEm.

Remarks. COLONIES fROm OAXAcA dIffEREd fROm AccOUNTS Of Clytia gracilis (SARS, 1850) bY CALdER (1991) fROm BERmUdA, ANd SchUchERT ( 2001, 2003) fROm IcELANd ANd INdONESIA. IN ThE mATERIAL fROm OAXAcA, gONOThEcAE LAcKEd A SUbTERmINAL cONSTRIcTION AS dEScRIbEd bY CALdER, ALThOUgh SchUchERT dId NOT dEScRIbE ThAT chARAcTER IN hIS mATERIAL. FURThERmORE, hYdROThEcAE ARE NOT AS ELONgATE AS dEScRIbEd bY bOTh AUThORS. ThE LATTER WAS ESTAbLIShEd bY SchUchERT (2001) AS ONE Of ThE mOST dISTINcTIVE chARAcTERS Of ThE SPEcIES, ALONg WITh ThE TILTEd mARgINAL cUSPS.

AddITIONALLY, ThERE ARE SOmE SPEcIES cONSIdEREd cLOSELY RELATEd TO C. gracilis . ThAT IS ThE cASE Of C. hemisphaerica (LINNAEUS, 1767) ANd C. elsaeoswaldae STEchOW, 1914 (LINdNER et al. 2011). ThOSE ThREE SPEcIES hAVE EVEN bEEN REgARdEd AS cONSPEcIfIc (LINdNER et al. 2011; CUNhA et al. 2017). HOWEVER, OUR mATERIAL ALSO dIffEREd mORPhOLOgIcALLY fROm C. hemisphaerica ANd C. elsaeoswaldae IN SOmE chARAcTERISTIcS. C. hemisphaerica PRESENTS OVOId gONOThEcAE WITh A SPIRAL RIdgE ON ThEIR WALLS (SEE SchUchERT 2001: 152, fIg. 132), WhILE gONOThEcAE IN OUR mATERIAL WERE cYLINdRIcAL, WITh SmOOTh WALLS. ON ThE OThER hANd, C. elsaeoswaldae cAN PRESENT NUmEROUS ANNULATIONS ALONg hYdROcAULUS (SEE STEchOW 1914: 122, fIg. 2); ELONgATEd hYdROThEcAE (SEE LINdNER et al. 2011: 27, fIg. 2A–E) ANd gONOThEcAE ARISINg fROm hYdRORhIZAE (LINdNER et al. 2011). ThIS IS ALSO dIffERENT fROm C. cf. gracilis fROm OAXAcA SINcE IT PRESENTEd fEWER, IRREgULAR ANNULATIONS; ShORTER hYdROThEcAE ANd gONOThEcAE ARISINg fROm STEm.

Distribution. PAcIfIc cOAST Of SOUThERN MEXIcO. KNOWN ONLY fROm ChAcAhUA bAY, OAXAcA.

Figures

FIGURE 4. Clytia cf. gracilis. A, pARt Of thE cOLONy; B, D, GONOthEcA; C, dEtAIL Of thE hydROthEcA; E, cLOSE-up Of thE tILtEd cuSpS. ScALE bARS: 50 µm (E), 200 µm (B‒D), 1 mm (A).