Pacific Science (1991), vol. 45, no. 4: 383-388© 1991 by University of Hawaii Press . All rights reserved

Cyclohelia lamellata, New Genus and Species of Stylasteridae(Cnidaria: Hydrozoa) from the Bering Seal

STEPHEN D. CAIRNS2

ABSTRACT: A new genus and species of Stylasteridae is described, Cyclohelialamellata, based on one specimen from 550 m off the Pribilof Islands, BeringSea. The species is unusual in having a lamellate growth form and unique inhaving elliptical dactylopore spines that are rimmed on all sides. The genus ishypothesized to be most closely related to Distichopora and Sporadopora.Cyclochelia lamellata is one of the most northerly records of a stylasterid in thePacific Ocean.

IN 1985, A DEEP-WATER crab fisherman,Michael Lake, snagged two stylasterid coralson his crab nets at a depth of about 550 m offthe Pribilof Islands. He gave them to AlanKohn of the University of Washington, who ,in turn, sent them to me for identification. Onespecimen was Crypthelia trophostega Fisher,1938, but the other specimen was unusual inthat it was lamellate in growth form, andit could not be placed in any of the stylasteridgenera. During the 5 yr since that specimenwas collected, no additional specimens havebecome available. Therefore, a new genusand species is described based on this singlespecimen.

Stylasterid morphological terminology andmethods of study are summarized in Cairns(1983).

Genus Cyclohelia Cairns, n. genus

DIAGNOSIS: Gastro- and dactylopores uni­formly distributed on corallum faces andedges; no coordination between types ofpores. Corallum a robust, solid lamella withsmaller lamellae at right angles to it. Coenos­teal texture reticulate-granular. Gastroporesflush with coenosteum; dactylopore tubeselongate (axial) . Gastrostyles ridged and quiteelongate; no tabulae. Dactylopore spines cir­cular to elliptical, enclosed by a thin wall for

1 Manuscript accepted 16 January 1991.2 Department of Invertebrate Zoology, National

Museum of Natural History, Smithsonian Institution,Washington , D.C. 20560.

entire perimeter; no dactylostyles. Ampullaeprimarily internal.

TYPE SPECIES: Cyclohelia lamellata, n. sp.,here designated.

ETYMOLOGY: The name Cyclohelia is a com­bination of cyclos (Greek for "circle") andhelios (Greek for "sun"), helia being a com­mon suffix in stylasterid generic names andherein interpreted to refer to the gastropores.The combination thus implies "having circu­lar gastropores." Gender: feminine.

DISCUSSION: Among the ca. 250 species ofstylasterids, virtually all species have abranching growth form . The exceptionsare the three species constituting the genusStylantheca, which are encrusting; and twospecies that form solid platelike lamella: Dis­tichopora anceps Cairns, 1978, and Errinoporananneca Fisher, 1938. The solid , lamellargrowth form was interpreted as a characterof subgeneric importance by Cairns (1978),forming the basis of the subgenus Haplo­merismos, but of only intraspecific value byFisher (1938), because specimens of Errino­pora nanneca occurred in both the branchingand lamellar growth form. For this reason, thelamellate growth form of Cyclohelia is notnecessarily considered to be diagnostic ofthe genus, but nonetheless important to note.The lamellar growth form of C. lamellata isidentical to that of Errinopora nanneca, andboth species are found in the North Pacificat approximately the same depths, but

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Cyclohelia differs in having axial gastro- anddactylopores; having long, needle-shaped,longitudinally ridged gastrostyles; having in­ternal ampullae; having ring palisades ; havingdifferently shaped dactylopore spines; and inlacking dactylostyles.

The affinities of Cyclohelia are closer to thegenera Sporadopora and Distichopora, whichare morphologically (Cairns 1983) and phy­logenetically (Cairns 1984, 1987) similar toone another. Cyclohelia is similar to Sporado­pora in having long, axial gastro- and dactylo­pores ; having internal ampullae; having long,longitudinally ridged gastrostyles; in lackingcoordination of gastro- and dactylopores;and in lacking dactylostyles. Sporadopora,however, differs in having circular, flushdactylopore spines; having a branchingcolony; and in lacking ring palisades. A re­examination of the type specimens of Spora­dopora mortenseni Broch, 1942, however,revealed that many of its dactylopores areslightly elevated and some are elliptical tohorseshoe-shaped, a characteristic that in­creases its resemblance to Cyclohelia, whichhas circular to elliptical dactylopore spineswith distinct walls surrounding all sides.

Cyclohelia resembles Distichopora in hav­ing long, axial dactylo- and gastropores;having long, longitudinally ridged, needle­shaped gastrostyles; having elliptical dactylo­pore spines; and in lacking dactylostyles. Onespecies in particular, D. anceps , is the mostsimilar, in having internal ampullae and alamellar (bilobate) growth form. Distichoporadiffers from Cyclohelia in the coordination ofits gastro- and dactylopores into pore rowsthat usually occur on branch edges and theshape of its dactylopore spines, which areusually rimmed on only three sides, beingflush on the side adjacent to the gastropore.

Another species, Distichopora providentiae(Hickson & England, 1909), known only fromProvidence Island in the Indian Ocean (229m), must also be discussed in the context ofcomparisons. The gastropores of D. provi­dentiae are only loosely arranged in pore rowson branch edges (Boschma 1959) and alsooccur on branch faces in little apparent order(Cairns 1983: fig. 16H). Hickson and England(1909 : 350) originally placed the species in

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Sporadopora, but noted its resemblanceto Distichopora, suggesting a sister-grouprelationship, which was later supported byphylogenetic analysis (Cairns 1984). Broch(1942 :27) emphatically placed the species inDistichopora, and Boschma (1959: 164) tenta­tively agreed . Cairns (1983: 436, 471) alsoplaced it in Distichopora, but suggested that itwas transitional between Distichopora andSporadopora. The seemingly random arrange­ment of gastro- and dactylopores on branchfaces of D. providentiae does resemble thatof Cyclohelia, but D. pro videntiae differs inhaving poorly defined pore rows on branchedges; having horseshoe-shaped dactyloporespines rimmed on only three edges; having abranching growth form; and in lacking ringpalisades.

Cyclohelia is distinguished from otherstylasterid genera by a combination of fiveincreasingly exclusive characters: lack ofcoordination of gastro- and dactylopores(shared with 11 of the 23 stylasterid genera[see Cairns, in press]); elongate, axial gastro­and dactylopore tubes (shared with onlyfive other genera : Distichopora, Sporadopora,Lepidopora, Pliobothrus, and Adelopora);needle-shaped, longitudinally ridged gastro­styles (shared only with Distichopora andSporadopora); lamellate growth form (sharedonly with one species of Distichopora and onespecies of Errinopora); and its circular toelliptical dactylopore spines that are rimmedon all sides, the walls being apically serrate(a character unique to Cyclohelia). Its ringpalisade also distinguishes Cyclohelia fromSporadopora and Distichopora, but nonethe­less it is considered to be phylogeneticallyclose to those genera.

Cyclonelia lamellata Cairn s, n. sp.Figures la -g, 2a-g

DESCRIPTION: Corallum ofholotype 7.0 cmtall and 9.5 em broad, with a basal en­crustation 3.7 x 1.8 em in diam. Corallumprimarily uniplanar, the main lamella sinu­ous, as well as having 2 smaller lamellaeoriginating at right angles to the main one.Distal part of lamellae 4-5 mm thick; basallamella about 15 mm thick . Reticulate-

FIGURE I. Cyc/ohelia lamella/a, holotype, USNM 85077: a, holotype colony (base to left), x 0.63; b-d, coenosteum,illustrating circular flush gastropores and elliptical dactylopore spines, female efferent pore present in center of figureb, x 36.5, x 23.5, x 54.5, respectively (b and dare stereo pairs); e-g, reticulate -spinose coenostealtexture, x 87, x 155,x 1135, respectively.

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granular coenosteum reddish-orange, with awhite central co re and slightly less pigmentedcoenosteum overlying each ampulla. Coenos­teal strips 73-140 Jlm wide, bordered byrelatively broad but discontinuous slits 25-30Jlm wide. Coenosteal strips covered with ro ­bust , smooth, pointed granules up to 33 Jlmtall and 2 1Jlm in basal d iameter. Coenosteumbetween granules smooth. Nematoporesabsent.

Gastro- and dactylopores occur abun­dantly and uniformly on corallum face s andedges, lacking any coordination between poretype. Gastropores circular, flush with coenos­teum, and variable in diam.: ranging from0.16 to 0.39 mm in diam., the two size classesoften occurring adjacent to one another.Gastropore tubes long (up to 2.8 mm deep inthick lamellae), cylindrical, and sometimescurved to follow axis of lamella. Diffuse ringpal isade present in vicinity of gastrostyle tipand slightly above it , composed of tall , blunt,cylind rica l elements up to 0.11 mm tall and0.03 mm in diam. G astrostyle needle-shaped,its tip usually ea sily visible in oral view inan undamaged gastropore. Illustrated gastro­style (Figure 2c) 1.24 mm long a nd 0.0 85 mmin diam. (exclusive of spines) for a H : W ratioof 14.6; however, gastrostyles in thi cker la­mellae ha ve ratios as high as 29. D espi te highH : W ratio s, tabulae are lacking. Gastrostyleslong itudinall y ridged, the rid ges bea ringdistally inclined, slender spines up to 60 Jlmlong and about 7 Jlm in diam.

Dactylopore spines circular to ellipticalin shape: the former ch aracteristic of small ,developing dactylopore spines (e.g., 0.10 mmin diam.), the latter of larger, fully developeddactylopore spines (e.g. , 0.35 x 0.21 mmin diam.). Upper surface of elliptical dacty­lopore spines usually convex such th at lateraledges of dactylopore spines a re higher thanthe vert ices of the ellipse. For example, atypic al , well-developed, elliptical dactyloporespine (F igure 2e) might have lateral edges0.18 mm tall but edges onl y 0.1 3 mm tall atits vertices . Outer wall of dactylopore spinessmooth a nd vertica l; upper edges serr a te,composed of a row of robust spinules similarin size and shape to coenosteal granules.

Fem ale ampullae large, closely packed,ellipsoidal cavities that occur primarily within

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coenosteum but sometimes rise as much as0.2 mm above coenosteal level as low , less­pigmented bulges. Internal greater diam. ofampullae 1.0-1.1 mm and lesser diam. about0.8 mm, the grea ter diam. parallel with coenos­teal surface. Efferent pores rarely observed,but occur apically on ampullae as a spongycoenosteal area about 0.11 mm in diam.(Fi gure Ib ). M ale ampullae unknown.

DISTRIBUTION: Cyclohelia lamel/ata is knownonly from the type locality off the PribilofIsl ands (ca. 57° N , 170° W). Together withCrypthelia trophostega Fisher, 1938, withwhich it was collected, it represents the thirdmost northerly record of a stylasterid in theNorth Pacific . The highest-latitude NorthPacific sty lasterid record is that of Stylastercampy leca (Fishe r, 1938) from 58° 17' N in th eGulf ofAlaska, and the second mo st northerl yreco rd is of Errina latifundata from 58° 02' N ,in the Sea ofOkhotsk (Naumov 1960). Severalsty lasterids are known from higher north ernlati tudes in the N orth Atlantic (Broch, 1914),as far as 66° 18' N (Arctic Circle) off Iceland.

ETYMOLOGY: The species name lamel/ata(Latin for " having lamellae" ) refers to theplat elike lamellae characteristic of the coloniesof this species.

TYPE MATERIAL: Holotype : 1 female co lonya nd SEM stub 435, USNM85077.

TYPE LOCALITY: " Tangled in crab ne ts a tabout 1800' (550 m) off Pribilof Islands,"Bering Sea.

ACKNOWLEDGMENTS

I would like to th ank Michael Lake for col­lecting th e specime n and Alan Kohn forall owing me to study it. I am also grate­ful to Helmut Zibrowius (Station Marined 'Endoume, Marseille) for helpful commentsduring the review stage.

LITERATURE CITED

BOSCHMA, H. 1959. Revision of th e Indo­Pac ific species of the genus Distichopora.Bijdr. Dierkd. 29 : 121-1 71.

Cyclohelia lamellata, New Genus and Species of Stylasteridae-CAIRNS 387

FIGURE 2. Cyclohelia lamellata, holotype , USNM 85077: a-b, d-e, various developmental stages of ellipticaldactylopore spines (note serrate upper edges), x 92, x 135, x 69, x 140, respectively; C, g, gastrostyle and diffuse ringpalisade, x ISS, x 300, respectively;/, two adjacent internal female ampullae (coenosteal surface to left), x 25.

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BROCH, H. 1914. Stylasteridae. Dan. Ingolf­Exped. 5(5): 1-28.

- - - . 1942; Investigations on Stylasteridae(Hydrocorals). Skr. Nor. Vidensk. Akad.Oslo 3: 1-113.

CAIRNS, S. D . 1978. Distichopora tHaplo­merismos) anceps, a new stylasterine coral(Coelenterata: Stylasterina) from deepwater off the Hawaiian Islands. Micro­nesica 14(1): 83-87.

- - - . 1983. A generic revision of the Sty­lasterina (Coelenterata: Hydrozoa). Part I.Description of the genera. Bull. Mar. Sci.33(2): 427-508.

- - - . 1984. A generic revision of the Sty­lasteridae (Coelenterata: Hydrozoa). Part2. Phylogenetic analysis. Bull. Mar. Sci.35( 1): 38-53.

- - - . 1987. Evolutionary trends in the Sty­lasteridae (Cnidaria, Hydrozoa). Pages

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257-274 in J. Bouillon, F. Boero, F.Cicogna, and P. F. S. Cornelius, eds .Modern trends in the systematics, ecology ,and evolution of hydroids and hydro­medusae. Clarendon Press, Oxford.

---. In press . A generic revison of theStylasteridae (Coelenterata: Hydrozoa).Part 3. Keys to the genera. Bull. Mar. Sci.

FISHER, W. K. 1938. Hydrocorals of theNorth PacificOcean. Proc. U . S. Natl. Mus.84(3024): 493-554.

HICKSON, S. J ., and H . M. ENGLAND. 1909.The Stylasterina of the Indian Ocean.Trans. Linn. Soc. London (2) 12:345-354.

NAUMOV, D. V. 1960. Keys to the fauna ofthe USSR, no. 70, Hydroids and Hydrorne­dusae of the USSR. Academy of Sciences,USSR, Moscow, 660 pp. [translated intoEnglish by Israel Program for ScientificTranslations, 1969]