THE \V:\SM:\XX JOUR NAL OF B J O L OGY \'oL ;4, Xo. I SPRII'C, 1976 A N ew Species of Aglauropsis (Hydrozoa: Limnomedusae) from the Northeastern Pacific, with Notes on Aglauropsis conantii and Eperetmus typus CLAU DIA MTLLS'. JOHX T REES, and CADET H:\1\D, Bodrga Marine L aboratory aud Depart mcul of Zoology, l.'uit·ersil y of Calijomia, Bndcga Bay, California 9-1913. l l'TRODUCTION ince 1960, an undescribed species of the Umnomedusan genus . lJ{Iauropsis has been collected from Lime to time in 01e plankton of Bodega Bay and Tomales Bay, central California. imi larities to Epcrctmus typus Bigelow {1915) h ave led us to a re-examination and reassessment of specimens from J apan reported to be E. t·ypus. We here describe this new Cali fo rnian Al(lauropsis, a genus pre­ viously recogni?.<'d only from the south Atlantic, and present ob­ servations on its behavior and ecology. We have adopted the spelling Olindiasidae for this family of Limnomedusae, as emended by 1\Ioreira and Yamashita {1972). ~ IETHODS exually mature medusae of Aglauropsis acora new species were collected in J une and July of 1972 and 1973 in Bodega Bay by means of surface plankton tows with a meter net. Live. healthy anima ls, including some ju\'eniles were also collected in beach wash on alrnon reck Beach which lies just north of Bodega Bay. ~I edusac were maintained in the laboratory in I 500 ml beakers of filtered sea water and gently aerated by means of ~-t l ass pipettes I l'rcsc•n( uc lc l c·c· >~: 70·1•1 50th Avenue N.E., Seattle. w :.<hlnglll ll 9Rl!.l. [23] 24 THE \\'ASMAX:\" JOUR.'\AL OF BIOLOGY, \'!1L.• 1-1 , Xo. I, 1976 fitted to sur~ica l tubi ng. TI1e beakers were placed in a shallow water table and maintained a t a temperature of about li"C. The water in the beakers was chan)!e<l every two to four days at which time the medusae were fed enou!!h 2-day old .lrtcmia larvae (2-4 concentratecl drops). so that a few brine shrimp would be remaining in the beakers when the water was next changed. :\Jedusae lived under these conditions for a maximum of 3 months. The animals slowly grew in size and juveniles attained fu ll maturity during this period. To induce spawni n~ medusae were kept overni~h l in a refrig­ erator a t 5"C. After warming a t room temperature for about 2 hours, they were returned to the water table nncl aerated. :Medusae would abo spawn spontaneously if left on the water table, but ch ill i n ~ seemed to yield a greater number of planulae. Although the release of C/-!gs and sperm are probably light-stimulated, we never obsen·ed this action. E g:gs were noted in the beaker about 2 hours after return to the water table. Planulae could consis­ tently be obtained with a pipette from the botlom of the beaker in which the medusae were held, about 2 days after spawning had occurred. Planulae were placed in finger bowls containing double-filtered sea w;tler and were cooled and aerated as described above. Planulae were found to settle underneath square pieces of glass sli des a r­ ranged lo cover the bottoms of Lhe finger bowls. After settlement Lhr glass pieces with planulae were removed to clean bowls con­ taining fresh, fi ltered sea water which were kept cool a nd gently aerated. De,·elopment of the primary polyp was observed on slides for 2 months. During this time the water was changed weekly and kept as free from debris as possible. Adult medusae of :J. glauropsis acora new species from Bodega Ba) were compared with the following preserved specimens: ( l ) Eprrclmus lypus Bigelow (1915) from , an Juan Island, \\"ashing­ ton and Yaquina Bay, Oregon: (2) Epcrctmus lypus of Uchida ( 1929) from Akkeshi Bay, Japan ; (3) .lglouropsis conontii Browne (1902) from near the east entrance of the Strait of 1\Iagcllan, South America: and (4) Aglauropsis kawari :\ fo reira and Yamashita ( I 972) from the souti1ern coast of Brazil. Ncmalocysts were measured undischarged from bolh live and preserved specimens of ,-J. acora new species from Bodega Bay LIM:>IOMED SA ~- ;\ I JLLS, REES & HA!IID 25 and from the pre. erved material listed above. ize ranj!es were de­ termined by meas urin~ at least 20 of each kind of nernatocyst, except in cases of uncommon varieties, where 5 I 0 were measured. Some fired nematocysts were stained with methylene blue to observe fine structure more clearly. Cnidoms were studied from seven specimens of :1 . acora new species, two specimens of . 1. conantii, two specimens of E. typus, and three specimens of " E. typus" from japan. Aglnuropsis ncora l\Iills, Rees & Hanel, new species. ( FJCUIIL:S 1-7) . l glaurop.!i; l>(>., R"-LS and II.\1\:D ( 19 i5:77, 8.1). Dt,\GNOsrs. Adult medusae with gonads hanging as a wavy cur­ tain with simple edges from the entire length of the radial canals. Lips of the manubrium bordered by a row of spherical nematocyst batteries. P dunde absent. D ESCR IPTION. Planulae are oval in shape, from 75 to 100 11m long and about 50 11m wide (fig. 1). Planulae settled from 4 to 12 days after being removed to clean fi nger bowls. The planulae were slightly adhesive and difficult to remove with a pipette from the bottom of a container. They did not swim extensively, but moved slowly aJo n~ the bottom, usually settling in the ~cn c ra l area where they were inilially placed in the bowl. Jn some cases, the planulae were observed to undergo "amoeboid" shape changes ( fi g. 2) . This occurred when they had crawled into the thin space between glass slides and the bottom of a finger bowl. ·o obvious net change of position occurred during this activity and its function is unknown. Settled planulae fla ttened into discs 75 p.m in diameter. Polyps, appearin~ as protuberances arising from the basal discs, were seen about 5 to 10 days after planular seulement (fig. I ). The discs were in many cases obscured by debris adhering to the bases of the polyps. About 1 month after settlement, 12 to 20 vertically oriented nematocysts were seen on the tips of the polyps, now 0.2 mm in height. All of the nematocysts were microbasic euryteles and measured 6.5-8.5 X 4.0-4.5 p.m in living polyps. Pieces of brine shrimp larvae were observed to be caught at the nematocyst-laden tips of several polyps, but no evidence of ingestion was seen. So me of the polyps contracted lo about l, ~ their height when touched 26 THE \\"ASMA'\X.. JOUR..\1:\L OF BIOLOGY, \ "oL .•1 4, Xo. 1, 1976 0 b OJ mm F1CUR£ I. Oc\"clopmenl of the primary polyp of .l glaurop.<is afora: a. ciliated rlanula; b. settled planula, top de\\ ; c. sclllcd planula, side \·icw; d, e. development 5 days after planular settlement ; f. polyt> with ncmatocysts 20 dnys after planular settlement. All arc drawn to scale. J2 THE \\"ASMA<\1\ JOUR!\AL OF BIOLOGY, VoL. 34, Xo. 1, l 9i 6 0 b 0 d e 0 F l l.UUI:: i Cnidom of Aglauropsit acora, from li\ 111~ material. Drawn ap­ pro:\imatch to calc. From primary polyp. a, microh:1sic cur) lclc. From adult medu53 tent:.ck's: b. microbasic eurytele , c. holotrichous isorhi.za. Lips of the manubrium: d. lar~e microbasic curytele , ,. small microbasic cury­ telc. r holotrichou5 isorbiza. for " fishing" or swimmjng. The adaptive significance of these pos­ tures appears to be that with full tentacle expansion the animal presents a maxi mal area for fi shing as it hangs molionJess or sinks through the water column, and while swimming the tentacles are shortened which reduces drag through the wnter. Medusae also LIMNOMEDUSAE-MlLLS, REES & HAND 27 OJ mm FIC:URE 2. ilglauropsis aeom planula undc r~ro in l! "amoeboid " chanJ.(CS in shape. A 2-minutc sequence is depicted. with a probe. o further development was evident and the polyps disappeared after about 5 weeks. The mature polyp and young medusa stages of AKlauropsis acora are unknow n. l\Iature adult medusae may reach 20 mm in diameter and 15 mm in height, with a thick, solid jelly (fig. 3). In life, the umbrella is bowl-shaped. The manubrium hangs down about ~:! the length of the bell cavity. The mouth has four large, flared, crenulated lips, bordered by a row of closely packed, spherical nematocyst batteries (fig. 4). The fo ur radial canals and the ring canal are broad. Curtainlike gonads extend the entire length of the radial canals, on mature specimens folding 4 or 5 times, separated by a short space from the manubrium and ring canal (fig.S) . About 200 FIGVI\E .3. Aglauropsis aeora, adult medusa. Dmwn from a photograph of a li ving animal 20 mm in bell diameter. 28 THE \VASMAI'\K JOUR:\AL OF BIOLOGY, VoL . .l4, :\o. I , 1976 TABLI:; I. Cnidom of A!!lauropsis aeora. All measurrme111s are of unfired cap.wles in p.m; from lh•ing material. ;. Iicrobasi c Hulotrichou; curytel<s i~rhit... 1 S Primary polyp 6.5-8.5 X .J.o-5.0 nol prcscnl :\dull medusa (20 mm diameter) tentacles 14- IS X 8-9 6-9 X 4 (many) (few) lips o f Lhc Size ] 13.2- 1 ~ .0 X 7.S-S.2 6.2- 7.2 x ;u-.u manubrium (few) ( icw) Size ll 6.5-10.0 X 3.5-6.2 (many) hollow tentacles, all of one kind, arise from the bell margin.