Sertularia dichotoma, (Linnaeus, 1758)

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: 461

publication ID

https://doi.org/10.11646/zootaxa.4455.3.3

publication LSID

lsid:zoobank.org:pub:BBEB2AB8-50D6-44F1-ABDC-F2A25FF814FF

persistent identifier

http://treatment.plazi.org/id/2A3D2545-BF0C-FFC1-8CDF-0DAB371FF863

treatment provided by

Plazi

scientific name

Sertularia dichotoma
status

 

Obelia dichotoma (Linnaeus, 1758) 

FIg. 5 View Figure

Sertularia dichotoma  LINNAEuS, 1758: 812.

Clytia longicyatha  .—FRASER, 1938A: 32.

Obelia tenuis FRASER, 1938A: 38, pL. 9, fIG. 42.

Obelia commissuralis.—FRASER, 1938A: 36.—FRASER, 1948: 213.

Obelia dichotoma  .—FRASER, 1938A: 36.—FRASER, 1948: 213.— MILLARd, 1975: 227, fIG. 75F‒H, J (SyN.).—CALdER, 1991: 72, fIG. 38 (SyN.).—KELmO & AttRILL, 2003: 138, fIG. 6G‒I (SyN.).—OkOLOdkOV et al., 2007: 40.—CALdER, 2012: 50, fIG. 51 (SyN.).— CuNhA et al., 2017: 118.

Obelia hyalina.—FRASER, 1938A: 37.—FRASER, 1938c: 133.—FRASER, 1948: 215.

Obelia plicata.—FRASER, 1938A: 38.—FRASER, 1938b: 109.—FRASER, 1948: 215.

Obelia biserialis FRASER, 1948: 213, pL. 24, fIG. 6.

Obelia gracilis  .—FRASER, 1948: 215.

Obelia griffini.—FRASER, 1948: 215.

Type locality. COAST Of SOUThWEST ENgLANd (CORNELIUS 1975). 

Material examined. NINE cOLONIES: UMAR-HYDR-007, fIVE cOLONIES ON Rhizophora mangle  ( CORRALERO BAYAbout BAY, OAXAcA, 16°13’04’’N 98°11’11’’W, 1 m, 11 JUNE 2015, cOLL. C. CRUZ-GómEZ); UMAR-HYDR-008, fOUR cOLONIES (MAZUNTE, OAXAcA, 15°39’46’’N 96°33’55’’W, ~ 20 m, 15 SEPTEmbER 2015, cOLL. F. RUIZ-EScObAR).

Description. COLONIES EREcT, 0.7–1.1 cm hIgh, SYmPOdIAL; ARISINg fROm A cREEPINg hYdRORhIZA. HYdROcAULUS mONOSIPhONIc, UNbRANchEd, ZIgZAg; dIVIdEd INTO INTERNOdES AT REgULAR INTERVALS. INTERNOdES SLIghTLY cURVEd, WITh TWO OR ThREE ANNULATIONS bASALLY; EAch ONE SUPPORTINg A hYdROThEcAL PEdIcEL ORIgINATINg fROm AN APOPhYSIS. PERISARc UNIfORm, ThIcK; TRANSLUcENT ( CORRALERO BAYAbout BAY SPEcImENS) OR bROWNISh (MAZUNTE SPEcImENS). APOPhYSES ShORT, ALTERNATE. PEdIcELS fROm 450 µm TO 1 mm LONg; WITh AbOUT EIghT ANNULATIONS PROXImALLY ANd SIX dISTALLY. HYdROThEcAE cAmPANULATE, UP TO 200 µm LONg, 275 µm WIdE AT mARgIN; TAPERINg AT bASE. HYdROThEcAL mARgIN NOTAbout NOT cOmPLETELY SmOOTh bUT WITh 12 SOfTLY cURVEd, ALmOST INdISTINgUIShAbLE LObES; SOmETImES ENTIRE. HYdRANThS WITh AbOUT 25 TENTAcLES, 180–200 µm LONg. GONOThEcAE cONE-ShAPEd, WITh SmOOTh WALLS; ELONgATEd, 500 µm LONg fROm bASE TO APERTURE, 300 µm WIdE (mAXImUm WIdTh); WITh A ShORT NEcK ANd dISTAL APERTURE; ARISINg fROm ANNULATEd PEdIcELS.

Remarks. ThE mORPhOLOgY Of cOLONIES fROm OAXAcA cOINcIdES WITh dEScRIPTIONS Of Obelia dichotoma  fROm SOUTh AfRIcA bY MILLARd (1975); fROm BERmUdA bY CALdER (1991); ANd fROm BRAZIL bY KELmO & ATTRILL (2003). ALThOUgh ThIS SPEcIES hAS bEEN REcORdEd IN OThER STATES ALONg ThE PAcIfIc cOAST Of MEXIcO, SUch REcORdS NEEd VERIfIcATION bEcAUSE Of ThE gREAT dISTANcE bETWEEN MEXIcO ANd ThE TYPE LOcALITY, ENgLANd. MOREOVER, SIgNIfIcANT dIffERENcES EXIST IN ENVIRONmENTAL cONdITIONS bETWEEN ThE TWO REgIONS, PARTIcULARLY IN WATER TEmPERATURES. Obelia dichotoma  IS cONSIdEREd A cRYPTOgENIc SPEcIES bY SOmE AUThORS (OKOLOdKOV et al. 2007) bEcAUSE Of ITS mULTIPLE REcORdS AROUNd ThE WORLd.

FURThERmORE, O. dichotoma  IS AmONg ThE mOST mORPhOLOgIcALLY VARIAbLE hYdROIdS (CORNELIUS 1990). ThOSE VARIATIONS ARE REfLEcTEd IN ThE mULTIPLE NEWAbout NEW SPEcIES dEScRIPTIONS, NOW cATALOgUEd AS ITS SYNONYmS. MOLEcULARLY, CUNhA et al. (2017) fOUNd OUTAbout OUT ThAT Obelia dichotoma  IS NOTAbout NOT mONOPhYLETIc ANd mIghT cORRESPONd TO A cOmPLEX Of cRYPTIc SPEcIES.

Distribution. Obelia dichotoma  WAS REPORTEd bY FRASER (1938A, b, 1948) fROm ThE MEXIcAN PAcIfIc AS dIffERENT SPEcIES, NOWAdAYS cONSIdEREd AS ITS SYNONYmS. AS fOR OAXAcA, IT WAS REPORTEd IN TANgOLUNdA bAY (FRASER 1938A, AS Obelia dichotoma  ANd Obelia commissuralis) ANd ChAcAhUA bAY (FRASER 1948). ThIS SPEcIES IS bELIEVEd TO bE cIRcUmgLObAL IN dISTRIbUTION (CALdER 1991; KELmO & ATTRILL 2003; CALdER 2012).

BAY

Mus�um d'Histoire Naturelle de Bayonne

NOT

Nottingham City Natural History Museum

NEW

University of Newcastle

OUT

Department of Biotechnology