Clytia linearis (Thornely, 1900)

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

Clytia linearis (Thornely, 1900)

FIg. 3

Obelia linearis ThORNELy, 1900: 453, pL. 44, fIG. 6.

Clytia acutidentata FRASER, 1938A: 28, pL. 7, fIG. 29.—FRASER, 1938b: 109.

Gonothyraea serialis .—FRASER, 1938c: 133.—FRASER, 1948: 212.

Clytia linearis .—CALdER, 1991: 62, fIG. 34 (SyN.).—ALtuNA PRAdOS, 1994: 59, fIG. 1, 2 (SyN.).—CALdER 1996: 258, fIG. 2 (SyN.).—LINdNER & MIGOttO, 2002: 541, fIG. 2.— SchuchERt, 2003: 160, fIG. 20 (SyN.).

Type locality. BLANchE BAY, NEW BRITAIN, PAPUA NEW GUINEA (CALdER 1991).

Material examined. FOUR cOLONIES: UMAR-HYDR-003, ThREE cOLONIES ON Rhizophora mangle ( CORRALERO BAY, OAXAcA, 16°13’04’’N 98°11’11’’W, 1 m, 11 JUNE 2015, cOLL. C. CRUZ-GómEZ); UMAR-HYDR-004, ONE cOLONY ON bRYOZOAN Amathia SP. ( SANTA CRUZ BAY, OAXAcA, 15°45’07’’N 96°07’52’’W, 1 m, 25 NOVEmbER 2015, cOLL. C. CRUZ-GómEZ ANd J.P. SáNchEZ-OVANdO).

Description. COLONIES EREcT, 1.4–2.3 mm hIgh, SYmPOdIAL; ARISINg fROm A cREEPINg hYdRORhIZA. HYdROcAULUS UNbRANchEd; STRAIghT (SPEcImENS fROm SANTA CRUZ) OR ZIgZAg, WITh INTERNOdES AT REgULAR INTERVALS (SPEcImENS fROm CORRALERO BAY). PERISARc UNIfORm, Of AVERAgE ThIcKNESS. PEdIcELS ShORT, AbOUT 150 µm, IRREgULARLY ANNULATEd; WITh 4–5 INcONSPIcUOUS ANNULATIONS mId-WAY ALONg PEdIcEL ANd 2–4 WELL-mARKEd ONES PROXImAL TO hYdROThEcAE. HYdROThEcAE bELL-ShAPEd, UP TO 270 µm LONg, 130 µm WIdE AT mARgIN; TAPERINg AT bASE. HYdROThEcAL mARgIN WITh AbOUT 10 ShARP cUSPS; EAch cUSP WITh A PLEAT EXTENdINg fROm ThE cUSP APEX TO mIddLE REgION Of hYdROThEcAE. GONOThEcAE NOT ObSERVEd.

Remarks. ThE hYdRANThS ANd PERISARc Of Clytia linearis EXhIbIT hIgh PLASTIcITY (LINdNER & MIgOTTO 2002). TWO dIffERENT mORPhOLOgIES Of ThE SPEcIES WERE fOUNd IN OUR SAmPLES, WITh ONE cOLONY TYPE ShOWINg ONLY ITS mAIN AXIS (ONE PEdIcEL) ANd ThE OThER, bEARINg AT LEAST SEVEN hYdROThEcAL PEdIcELS. WE REgARd ThE fIRST mORPhOTYPE TO bE AN EARLY STAgE ThAT hAd NOT YET dEVELOPEd PEdIcELS NOR hYdROcLAdIA; NEVERThELESS, LINdNER & MIgOTTO (2002) dEScRIbEd ThE SPEcIES AS RARELY bRANchEd. AS fOR STEm ANNULATIONS, ALTUNA PRAdOS (1994) REPORTEd 20–50 WhILE LINdNER & MIgOTTO (2002) REPORTEd 4–28 dISTALLY. OUR mATERIAL IS SImILAR TO ThE LATTER. AgAIN, SUch VARIATIONS mAY bE dUE TO dIffERENcES IN EcOLOgIcAL cONdITIONS. AN ALTERNATIVE EXPLANATION TO ThOSE SUbTLE mORPhOLOgIcAL VARIATIONS mIghT bE ThE EXISTENcE Of cRYPTIc LINEAgES WIThIN C. linearis , A SITUATION PREVIOUSLY ObSERVEd IN OThER SPEcIES Of Clytia ( CUNhA et al. 2017).

Distribution. Clytia linearis WAS REPORTEd bY FRASER (1938A, b, c, 1948) fROm BAjA CALIfORNIA SUR ANd SINALOA, MEXIcO. AfTERWARdS, CALdER (1996) REPORTEd ThE SPEcIES fROm ROcAS ALIjOS, BAjA CALIfORNIA SUR. CALdER (1991) ANd LINdNER & MIgOTTO (2002) cONSIdEREd C. linearis TO bE cIRcUmgLObAL IN ShALLOW WARm WATERS; AccORdINg TO SchUchERT (2003) IT IS dISTRIbUTEd IN TROPIcAL ANd SUbTROPIcAL WATERS. ThIS IS ThE fIRST REcORd Of ThE SPEcIES IN OAXAcA.

Figures

FIGURE 3. Clytia linearis (ThORNELy, 1900). A, cOLONy; B, hydRANthS ON Amathia Sp.; C, dEtAIL Of thE hydROthEcA. ScALE bARS: 100 µm (C), 250 µm (B), 500 µm (A).