Dynamena crisioides Lamouroux, 1824

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 : 464

Dynamena crisioides Lamouroux, 1824

FIg. 7

Dynamena crisioides LAmOuROux, 1824 : 613, pL. 90, fIGS. 11‒12.—CALdER, 1991: 62, fIG. 34.— SchuchERt, 2003: 170, fIG. 28 (SyN.).

Thuiaria crisioides .—FRASER, 1948: 250 (SyN).

Type locality. MOLUccAS, INdONESIA ( SchUchERT 2003).

Material examined. ELEVEN cOLONIES: UMAR-HYDR-010, ELEVEN cOLONIES ON ROcKS (PANTEóN BEAch, OAXAcA, 15°39’50’’N 96°29’43’’W, 1 m, 17 JANUARY 2015, cOLL. K.J. HUmARA-GIL).

Description. COLONIES EREcT, 1.6–4.2 cm hIgh, ARISINg fROm A cREEPINg hYdRORhIZA. HYdROcAULUS mONOSIPhONIc, ZIgZAg; dIVIdEd INTO INTERNOdES bY INdISTINcT NOdES. BASAL PORTION Of hYdROcAULUS WITh ONE OR TWO AThEcATE INTERNOdES. ThEcATE INTERNOdES WITh A hYdROcLAdIAL APOPhYSIS, AN AXILLIARY hYdROThEcA ANd ONE OR TWO SUbOPPOSITE PAIRS Of hYdROThEcAE. PERISARc ThIcK, YELLOWISh. APOPhYSES ShORT, ALTERNATE; dELImITEd fROm hYdROcLAdIUm bY A dISTAL NOdE. HYdROcLAdIA UNbRANchEd, TYPIcALLY STRAIghT; dIVIdEd INTO INTERNOdES WITh TWO OR ThREE SUbOPPOSITE PAIRS Of hYdROThEcAE. HYdROThEcAE TUbULAR, AdNATE fOR AbOUT 1/7 Of ThEIR AdcAULINE LENgTh, TILTEd TOWARdS AbcAULINE SIdE. AbcAULINE WALL 400 µm LONg; AdcAULINE WALL AdNATE TO hYdROcAULUS 370 µm LONg, 80 µm fREE. HYdROThEcAL mARgIN WITh TWO LARgE LATERAL cUSPS ANd ONE SmALLER AdcAULINE; OPERcULUm cOmPOSEd Of TWO VALVES, LOWER LARgER ThAN UPPER. GONOThEcAE OVAL, 800 µm LONg fROm bASE TO APERTURE, 600 µm WIdE AT mIddLE; WITh A cONSTRIcTION ON UPPER SIdE fORmINg A NEcK; fOUNd mOSTLY ON LOWEST PART Of hYdROcAULUS.

Remarks. ThE mORPhOLOgY Of SPEcImENS fROm OAXAcA AccORdS WITh ThE SPEcIES REdEScRIPTION bY SchUchERT (2003), ALThOUgh ThE NUmbER Of TENTAcLES cOULd NOT bE VERIfIEd. ThE SPEcImEN WAS ObSERVEd AfTER bEINg fIXEd, ANd EVEN ThOUgh IT hAd bEEN NARcOTIZEd, hYdRANThS REmAINEd WIThIN ThE hYdROThEcAE. AS A RESULT, TENTAcLES cOULd NOT bE ObSERVEd ANd cOUNTEd.

Distribution. ThIS SPEcIES hAS bEEN REPORTEd EARLIER fROm OAXAcA bY FRASER (1948, AS Thuiaria crisioides ), fROm TANgOLUNdA. OUR REcORd EXTENdS ITS KNOWN dISTRIbUTION WESTWARdS TO PANTEóN bEAch, PUERTO ÁNgEL. ThE dISTRIbUTION Of ThIS SPEcIES IS bELIEVEd TO bE cIRcUmgLObAL IN TROPIcAL ANd SUbTROPIcAL WATERS (CALdER 1991; SchUchERT 2003).

Figures

FIGURE 7. Dynamena crisioides LAmOuROux, 1824. A, cOLONy; B, GONOthEcAE; C, uppER hydRANthS; D, dEtAIL Of thE VALVES. ScALE bARS: 50 µm (D), 200 µm (C), 500 µm (B), 5 mm (A).