Redescription of Alatina alata (Reynaud, 1830) (Cnidaria: Cubozoa) from Bonaire, Dutch Caribbean Author Lewis, Cheryl Biological Sciences Graduate Program, University of Maryland, College Park, MD 20742, USA; dkeil @ umd. edu; clames 1 @ umd. edu National Systematics Laboratory, National Museum of Natural History, MRC- 153, Smithsonian Institution, P. O. Box 37012, Washington, DC 20013 - 7012, USA. E-mail: collinsa @ si. edu dkeil@umd.edu Author Bentlage, Bastian Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA. E-mail: bastian. bentlage @ gmail. com Author Yanagihara, Angel Department of Tropical Medicine, Medical Microbiology and Pharmacology John A. Burns School of Medicine, University of Hawai’i at Manoa, Honolulu, Hawai’i 96822, USA. E-mail: ayanagih @ hawaii. edu Author Gillan, William Palm Beach County (FL) Schools, Boynton Beach Community High School, 4975 Park Ridge Boulevard, Boynton Beach, FL, 33426, USA. E-mail: william. gillan @ palmbeachschools. org Author Blerk, Johan Van Kralendijk, Bonaire, The Netherlands. E-mail: blerkbonaire @ hotmail. com Author Keil, Daniel P. Biological Sciences Graduate Program, University of Maryland, College Park, MD 20742, USA; dkeil @ umd. edu; clames 1 @ umd. edu National Systematics Laboratory, National Museum of Natural History, MRC- 153, Smithsonian Institution, P. O. Box 37012, Washington, DC 20013 - 7012, USA. E-mail: collinsa @ si. edu dkeil@umd.edu Author Bely, Alexandra E. Biology Department, University of Maryland, College Park, MD 20742, USA. E-mail: abely @ umd. edu Author Collins, Allen G. text Zootaxa 2013 2013-11-21 3737 4 473 487 journal article 10.11646/zootaxa.3737.4.8 1175-5326 PMC4900819 25112765 5270497 B12F5D90-E13A-4ACA-8583-817DB0F6FD18 Species Alatina alata ( Reynaud, 1830 ) Table 1, Figs 1–6 Carybdea (medusa) alata Reynaud, 1830 (in Lesson 1830 , pl. 33, Fig 1a ) Marsupialis alata Lesson, 1837 , p. 9, n. 26; Lesson, 1843 , p. 278 Tamoya alata Agassiz, 1862 , p. 174 Charybdea alata Haeckel 1880 , p. 441; p. 42; 1940a, p. 5 Carybdea alata Mayer 1910 , p. 508–510; Bigelow, 1918 , p. 400; 1938, pp. 144–151, Text–Figs 11–16; Kramp, 1961 , p. 304; Arneson 1976, pp. 36, Figs 1 , 2 , Table 1,2, pl. I–V; Arneson and Cutress, 1976 , pp. 227–236, Table 1, pl. I A–G; Cutress, 1971, p. 19, pl. 1; Larson, 1976 , pp. 242; Larson et al. 1991 , p. 313, Table 2; Humann & Deloach, 2002 ; Morandini, 2003 , p. 15–17, Fig. 2 ; Gershwin 2005 pp. 501–523 ; Calder 2009, pp. 12, 13, Fig. 1 ; Bentlage 2010, p. 52; Bentlage et al. 2010 , p. 498; Bentlage and Lewis, 2012 , p. 2602 Carybdea alata var. grandis Graham 1998 , pp 28–30; Material examined. Neotype : USNM 1195802 , 1 ind, female, BW 40 mm , BH 70 mm (live), BW 30 mm , BH 69 mm (preserved), 24 June 2011 , Karel's Pier, Kralendijke, Bonaire, The Netherlands , 12 09' 06.37 N 6816' 40.84 W , depth = surface. Other material. Collected and identified by Lewis et al ., depth = surface: USNM 1205450 , 1 ind, female, BW 26 mm , BH 78 mm ; USNM 1205449 , 1 ind, female, BW 38 mm , BH 77 mm ; USNM 1205448 , 1 ind, male, BW 24 mm , BH 64 mm ; USNM 1205447 , 1 ind, female, BW 31 mm , BH 83 mm ; USNM 1195807 , 1 ind, female, BW 27 mm , BH 80 mm ; USNM 1195806 , 1 ind, male, BW 30 mm , BH 75 mm ; USNM 1195805 , 1 ind, male, BW 49 mm , BH 77 mm ; USNM 1195804 , 1 ind, male, BW 29 mm , BH 84 mm ; USNM 1195803 , 1 ind, female, BW 32 mm , BH 50 mm ; USNM 1195801 , 1 ind, female, BW 30 mm , BH 83 mm , 25 June 2011 , Karel's Pier , Kralendijke , Bonaire , The Netherlands , 12 09' 06.37" N 68 16' 40.84" W . Collected by Ross et al. and identified by Bentlage, B .: USNM 1131246 , 1 ind, gonads absent, BW 22 mm , BH 47 mm , 28 Aug 2007 , depth = 98–133 m (bottom depth = 468–595 m ), Lease Block VK 826, Gulf of Mexico , 29 09' 34.99" N 88 01' 19.99" W . USNM 1131245 , 1 ind, gonads absent, BW 19 mm , BH 25 mm , 25 Aug 2007 , depth = surface (bottom depth = 2206–2282 m ), Lease Block AT 340, Gulf of Mexico , 27 38' 38.00" N 88 20' 59.99" W . Identified by Burnett, J.W .: USNM 94780 , 1 ind, female, BW 24 mm , BH 55 mm , Feb 1992 , Guantanamo Bay , Cuba , Caribbean Sea. Collected by U S Navy , identified by Larson , R . J.: USNM 58692 , 1 ind, gonads absent, BW 17 mm , BH 30 mm , 3 June 1970 , depth = 55m , Ocean Acre Area , Off Bermuda , North Atlantic , 31 55' 59.99 N 64 25' 00.00 W . USNM 58691 , 1 ind, gonads absent, BW 7 mm , BH 17 mm , 7 Sept 1968 , depth = 327–335 m , Ocean Acre Area , Off Bermuda , North Atlantic , 31 52' 59.99 N 64 25' 00.00 W . USNM 58655 , 1 ind, male, BW 20 mm , BH 49 mm , 28 Oct 1967 , depth = 550–675 m , Ocean Acre Area , Off Bermuda , North Atlantic , 32 34' 59.99 N 63 58' 00.00 W . USNM 58316 , 1 ind, gonads absent, BW 8 mm , BH 16 mm , 28 Oct 1967 , Depth = 55m , Ocean Acre Area , Off Bermuda , North Atlantic , 31 55' 59.99" N 64 25' 00.00 W . USNM 54367 , 1 ind, gonads absent, BW 8 mm , BH 22 mm , Apr 27 1969 , depth = 0–300 m , Open Ocean Area , Off Bermuda , North Atlantic , 31 55' 00.00 N 67 57' 00 W . USNM 54366 , 1 ind, gonads absent, BW 16 mm , BH 55 mm , 25 Apr 1968 , depth = 350 m , Open Ocean Area , Off Bermuda , North Atlantic , 31 55' 59.99 N 63 46' 00.00 W . USNM 53694 , Open Ocean Area , 1 ind, gonads absent, BW 5 mm , BH 9 mm , 6 Apr 1967 , depth = 224–298 m , Off Cape Hatteras , North Atlantic , 35 02' 59.99 N 74 40' 59.99 W . U SNM 53659, 4 ind(s) gonads absent, BW 26 mm , BH 51 mm , BW 10 mm , BH 22 mm , BW 10 mm , BH 24 mm , BW 10 mm , BH 22.5 mm, 1 ind sex undetermined, BW 19 mm , BH 47 mm , 28 Sept 1965 , depth = surface, Caracas , Caribbean Sea , 10 54' 00 N 67 58' 00.00 W . Identified by Larson : USNM 58211 , 1 ind, female, BW 22 mm , BH 75 mm , 3 Apr 1978 , Carrie Bow Cay , Lagoon , Dock , Belize , Caribbean Sea . USNM 58210 , 1 ind, female, BW 25 mm , BH 52 mm , 25 Mar 1978 , Carrie Bow Cay , Lagoon , Dock . USNM 54472 , 4 ind(s), female 1, BW 16 mm , BH 58 mm , female 2, BW 18 mm , BH 64 mm , gonads absent, BW 17 mm , BH 32 mm , sex undetermined, BW 26 mm , BH 43 mm , 13 Oct 1974 , Mona Island , Caribbean Sea , 18 04' 0.00 N 67 52' 59.99 W . USNM 54398 , 5 ind(s), female, BW 8 mm , BH 17 mm , gonads absent, BW 7 mm , BH 19 mm , sex undetermined 1, BW 6 mm , BH 20 mm , sex undetermined 2, BW 8 mm , BH 16 mm , sex undetermined 3, BW 7 mm , BH 18 mm , 13 Oct 1974 , Mona Island , Caribbean Sea , 18 04' 00.00 N 67 52' 59.99 W . Collected by Lea and identified by Larson , R .J.: USNM 56737 , 1 ind, gonads absent, BW 10 mm , BH 20 mm , 11 Sept 1977 , depth = 0–90 m , Open Ocean Area , Off Delaware , North Atlantic , 37 20' 41.99 N 69 10' 23.99 W . USNM 56736 , 1 ind, gonads absent, BW 10 mm , BH 17 mm , 17 Sept 1977 , depth = 0–50 m , Open Ocean Area , Off Delaware , North Atlantic , 37 18' 24.00 N 66 51' 24.00 W . USNM 56735 , 1 ind, gonads absent, BW 6 mm , BH 8 mm , 10 Sept 1977 , depth = 0–150 m , Open Ocean Area , Off Delaware , North Atlantic , 37 49' 59.99 N 67 25' 23.99 W . Collected by Chase and Nicholson , identified by Larson , R .J.: USNM 54385 , 2 ind(s), female 1, BW 30 mm , BH 80 mm , female 2, BW 34 mm , BH 100 mm , 4 Apr 1956 , Freemans Bay , English Harbor , Antigua Island , Caribbean Sea. Collected and identified by Bigelow, H.B : USNM 42017 , 1 ind, female, BW 29 mm , BH 78 mm , 30 Jan 1914 , depth = 0–100 m , Open Ocean Area , E of Cape Romain , North Atlantic , 32 32' 59.99 N 72 13' 59.99 W . USNM 41921 , 1 ind, gonads absent, BW 17 mm , BH 37 mm , collected 21 Mar 1914 , depth = surface, N of Little Bahama Bank , Bahamas , North Atlantic , 27 46' 00.00 N 78 46' 00.00 W . USNM 41920 , 1 ind, gonads absent, BW 18 mm , BH 40 mm , 18 Mar 1914 , depth = surface, N of Havana , Cuba , Caribbean Sea , 22 31' 59.99 N 81 47' 59.99 W . USNM 41919 , 1 ind, gonads absent, BW 19 mm , BH 36 mm , 3 Mar 1914 , depth = surface, W of Eleuthera Island , Bahamas , North Atlantic , 25 26' 59.99 N 77 16' 00.00 W . Catalogued multimedia material (no specimen collected). USNM 1195809 , filmed by Harbison , R & Widde, E et al., identified by Larson , R (in Larson et al. 1991 ), still frame from a video voucher taken from the JSL manned submersible, 11 Nov 1989 , depth = 540 m (range = 457–610 m ), 26 04' 00.00 N 77 32' 59.99 W , Off Gordon Cay , 96 NM Off Rock Point . USNM 1005621 , photographed by Continental Shelf Associates for BLM / MMS and Texas A & M University taken from ROV SeaROVER, identified by Lewis, C. , photo voucher, Aug 1998 , depth = 96.5–108.7 m, 29 19' 39 N 87 46' 00.00 W , Mississippi , MMS Lease Block Destin Dome 661 , MMS –MAPTEM/M3–4, Gulf of Mexico . Neotype locality. Bonaire , Dutch Caribbean (Atlantic Ocean) Diagnosis. Alatina with tall narrow bell, flared at base, tapering into truncated pyramid at apex; 4 crescentric gastric phacellae at interradial corners of stomach; 3 simple to palmate branching velarial canals per octant, each with a velarial lappet bearing a row of 3 to 4 nematocyst warts; 4 long wing–like ( sensu Reynaud 1830 ) pedalia, each with a pink tentacle. Cnidome consisting of heterotrichous microbasic p–euryteles and small birhopaloids in tentacles, and large isorhizas in nematocysts warts. Description ( Figs 1–6 , Table 1). Neotype Fig 2a–f . FIGURE 1 . Line drawings of A. alata reproduced from Reynaud (1830) and Bigelow (1938) (as Carybdea alata ). A. Whole body showing bell, tentacles and pedalia (reproduced from Reynaud (1830) . B–G, Reproduced from Bigelow (1938) . B. Pedalium, C. Velarial canals (BH = 70 mm), D. Velarial canals (BH = 90 mm), E. Rhopalial niche with T–shaped opening, F. Bell apex showing crescentric gastric phacellae, G. Dissected gastric phacella (comprising gastric cirri). Abbreviations: i = interradius (location of pedalium), p = perradius (location of frenulum), vec = velarial canal (three per quadrant, simple to branching). Mature female specimen (BW 40 mm , BH 70 mm live; BW 30 mm , BH 69 mm preserved), with tall narrow bell flared at base ( Fig 2a ), tapering into truncated pyramid at apex. Each interradial corner bearing a pedalium: 3 of the 4 pedalia long and broad (approximately 15 mm wide) and wing–like, each bearing a pink tentacle (2a, c) about 2 mm in diameter, with bands of nematocysts along the entire length ( Fig 2c, e ). Fourth pedalium bearing a remnant of a tentacle (only several millimeters in height and width), much smaller and thinner than the other three (possibly damaged while being photographed together with other live specimens in an aquarium). Bell transparent and colorless in life ( Fig 2a ), translucent in fixed specimens ( Fig 2e ); exumbrella speckled with nematocyst warts. Stomach shallow ( Fig 2b ), lacking mesenteries. Manubrium short ( 2–3 mm long), wide and flat, with 4 mouth lips curled at the tips. Each of the four corners of the stomach housing a crescentric gastric phacella bearing about 20 gastric cirri ( Fig 2a, b ). A pair of leaf–like gonads, flanking each interradial septa and extending into the gastro– vascular cavity, filled with developing oocytes ( Fig 2a, b ). Adjacent gonads (i.e., ovaries) overlapping in the gastrovacular cavity, disassociated into large pieces following rupture due to internal fertilization event prior to preservation in formalin. Clumps of eggs found in various parts of the gastrovascular system (e.g., the velarial and pedalial canals, and the gastric pockets). Velarium wide, suspended by 4 perradial muscular brackets (frenulae) bracing the subumbrellar wall. Each octant bearing 3 simple to palmate branching velarial canals (variable with each octant), with the pair flanking the peradial frenulum simple to bifurcating, those flanking the pedalia at the interadius bifurcating as two main branches each with 3 to 4 distal branches (up to 7 branches in total), with the velarial canal in between bearing three distal branches ( Fig 2d ). Velarial canals in the two octants flanking the diminutive pedalium are not organized in the regular orderly fashion seen in the 6 other octants. Additionally, the velarium is torn near the base of the smaller pedalium, making it difficult to count the number of velarial canal branches there (N.B. the damaged pedalium is not readily apparent in the live photographs of the neotype specimen, and its small size may be exaggerated due to shrinkage following fixation in formalin). A new cubozoan character was discovered that appears to have been overlooked by previous workers. The structure which we call velarial lappets is found in sets of three in each octant overlaying the proximal two thirds of each velarial canal, each bearing a row of 3 to 4 nematocyst warts ( Fig 2d ). Four club–shaped rhopalia ( Fig 2a ), each situated just above the point where the frenulum connects to the subumbrella bearing 2 median lensed eyes, 2 lateral slit eyes, 2 lateral pit eyes, and 1 statocyst ( Fig 2f ). Rhopaliar niche opening T–shaped ( sensu Gershwin 2005 ), with a single upper scale and 2 lower scales ( Fig 2f ). Nematocyst warts are scattered over the entire exumbrella and bell apex; occurring in rows varying in number along the pedalial keel and the rhopalial niche scales ( Fig 2f ). Cnidome characterized below. FIGURE 2 . A. alata neotype (USNM 1195802 unless otherwise specified) from Kralendijk, Bonaire, The Netherlands. A. Mature female medusa (live), whole body (live, BW = 40, BH = 70). B. Apical portion showing stomach and crescentric gastric phacellae, visible in each corner, and wide central manubrium opening into subumbrella in live medusa. C. Pedalium and tentacle of live medusa. D. Velarial canals (3 per octant) in preserved medusa: each bears a row of 3 nematocyst warts on proximal first half to two thirds (on the velarial lappets) (dashed arrows indicate the main three velarial canals and branches extending from the main base of each canal). E. USNM 1195803–1195806, preserved mature medusae from the same locality as the neotype. F. T–shaped rhopalial niche opening with nematocyst warts on upper and lower scale coverings in live medusa. Live photographs by T. Peters (Fish Eye Photography, Bonaire) & A. Yanagihara. Abbreviations: cc = circular canal, fre = frenulum, g = gonads, i = interradius, lsc = lower scale of rhopalial niche covering, nw = nematocyst wart, ph = gastric phacellae (comprises gastric cirri), pc = pedalial canal, pd = pedalium, rh = rhopalium, rno = rhopalial niche opening, rst = rhopalial stalk, sta = statocyst, sto = stomach, te = tentacle, usc = upper scale of rhopalial niche covering. Scale bars: 5 mm (B & F). FIGURE 3 . Alatina alata from Kralendijk, Bonaire, The Netherlands (same location as neotype). A. & B. USNM 1195807, velarial canals (3 per octant) in preserved medusa, simple to branching (one outlined with dotted line in Fig 3A). Each canal bears a row of 3 nematocyst warts on the proximal first half to two thirds, i.e., on the velarial lappets. A clump of disassociated eggs is seen within the velarial canal on the left. C. USNM 1195802 (neotype), velarium of live medusa, partially pushed out revealing velarial canals. D. USNM 1195806, double layered frenulum anchoring the subumbrella to velarium at perradius. E. USNM 1195807, nematocyst wart on velarial lappet filled with isorhiza nematocysts. F. USNM 1195804, rhopalium dissected from preserved medusa, bears two median complex eyes, two upper lateral pit eyes, and two lower lateral slit eyes. G. USNM 1195806, subumbrella view of rhopalial window of preserved medusa, outline of rhopalial niche opening visible. Live photographs by T. Peters (Fish Eye Photography, Bonaire) & A. Yanagihara. Abbreviations: cel = complex eye lens, fre = frenulum, g = gonads, nw = nematocyst wart, pc = pedalial canal, pe = pit eye, pd = pedalium, rh = rhopalium, rno=rhopalial niche opening, rst=rhopalial stalk, se=slit eye, sta=statocyst, usc=upper scale of rhopalial niche covering. ve = velarium, vec = velarial canal, vel = velarial lappet. Scale bars: 5 mm (A & D), 10 mm (C), 1 mm (E), 3 mm (G). FIGURE 4 . Alatina alata specimens, preserved and live (all except A–C from Kralendijk, Bonaire (The Netherlands) the same locality as the neotype). A. USNM 53659, oral view of manubrium and four crescentric gastric phacellae in each corner of the stomach (BW = 19 mm, BH = 47 mm). B. USNM 53659, dissected tuft of gastric cirri from crescentric gastric phacella. C. USNM 53659, dissected gastric cirri, appearing as central mass in stomach of developing medusa (BW = 10 mm, BH = 22 mm). D. USNM 1195807, gastric phacellae and adjacent ripe paired gonads in preserved female medusa. E. USNM 1195807, dissected crescentric gastric phacella from mature medusa. F. USNM 1195806, lateral view of manubrium with mouth lips curled up. G. Live mature medusa, gonads beginning to rupture following a reproductive swarming episode (live, BW = 60, BH = 90). H. USNM 1195807, gonads dissected from mature female, bilayer of mature oocytes visible along adradial point of rupture. Live photographs by T. Peters (Fish Eye Photography Bonaire) and A. Yanagihara. (Fish Eye Photography, Bonaire). Abbreviations: eg = eggs, gc = gastric cirri, ma = manubrium, ml = mouth lips, pb = primary branch, ph = gastric phacellae (comprises gastric cirri), is = interradial septum. Scale bars: 5 mm (A & D), 2mm (B, C, E, F, H). FIGURE 5 . Cnidome of Alatina alata (all extracted from preserved material unless specified otherwise). A. Nematocyst bands along the length of the tentacle of a live specimen collected in Bonaire (June 2013). B. & E. Undischarged, microbasic heterotrichus p–euryteles extracted from tentacles; filaments associated with euryteles in B (USNM 1195807). C. Discharged microbasic heterotrichus p–eurytele extracted from tentacles of live medusa. D. Lancet contiguous with discharged tubule of microbasic heterotrichus p–eurytele extracted from tentacles (USNM 1195805) F. Small undischarged birhopaloid found in tentacles of preserved specimen USNM 1195807. G. Large undischarged holotrichus isorhizas found in nematocysts warts (i.e., bell warts & velarial lappet warts (USNM 1195802, neotype). H. Large discharged holotrichus isorhizas found in bell warts (USNM 1195802). H. Abbreviations: cp = capsule, fl = filaments, ln=lancet, nbnd=nematocyst band, sft=shaft, tb=tubule. Scale bars: ~150 µm (A), 10 µm (B, E, F), 25 µm (C), 20 µm (G, H). Other material. Medusae measurements are given as min– mean –max values, and were made on preserved specimens unless otherwise stated. In addition to the neotype , forty five A. alata specimens were examined (BH = 8– 48 – 100 mm , BW = 5– 20 – 49 mm ). Bells tall, narrow truncated pyramids like the neotype ( Fig 1a ; 4g , 6a–c ). Four long wing–like pedalia ( Fig 1b ; 3c ; 6a–c ), each with a single highly contractile tentacle, round in cross–section, ‘fluorescent’ pink in both live and preserved specimens, with numerous bands of nematocysts along the length ( Fig 5a ). Wide velarium ( Fig 1c, d ; 3a–d ), suspended by 4 perradial muscular brackets (frenulae) bracing the subumbrellar wall ( Fig 3a–d ). Twenty four simple to branching velarial canals, 3 per octant, extending from the gastro–vascular space of the bell into the velarium ( Fig 1c, d ; 3a–c & e ). Velarial canals flanking perradial frenulae simple, bifurcating distally, or giving rise to side branches; those flanking interradial pedalia splitting into two distinct sub–branches in first half to two– thirds of main branch; subsequent branching increasing in complexity (on average 4 sub–branches per primary branch; maximum 10), making it difficult to trace velarial canal tips back to the original branch, and often giving the appearance of greater than 3 primary velarial canals per octant ( Fig 1c, d ; 3a, b ). Bifurcating velarial canals in individuals as small as BH = 8 mm ; some canals with three branches in individuals of BH = 16 mm . Larger medusae generally displaying more highly branched velarial canals; wide variation exists between each octant in a single individual (1 to 5 branches seen per canal). Velarial lappets are thick gelatinous pouch–like structures comprising the proximal 50–75% of each velarial canal (24 total; 3 per octant), each bearing a row of 3–4 nematocyst warts ( Fig 3a, b, e ), function unknown. Bell transparent and colorless in life ( Fig 4g , 6a–c ), translucent in fixed specimens, speckled with nematocyst warts (nematocyst warts in older material were often lacking, and may have rubbed off in collection gear or after many years in preservation fluids, despite velarial lappet warts being still recognizable in most specimens). Rhopaliar niche opening T–shaped ( sensu Gershwin 2005 ), with a single upper scale and 2 lower scales enclosing the rhopalial niche ( Fig 1e ). Four club–shaped rhopalia, each with 2 median lensed eyes, 2 lateral slit eyes, 2 lateral pit eyes, and 1 statocyst ( Fig 3f, g ). All eyes are conspicuous in newly collected material from Bonaire , but in older preserved museum specimens the lens eyes are discolored (having a brown tinge), and bilateral paired pigmented pit eyes and slit eyes are faded to absent, leaving only the complex lens eyes visible. This may be an artifact of prolonged exposure to fixatives. Stomach shallow, lacking mesenteries; manubrium short ( 2–3 mm long), wide and flat, 4 mouth lips curled at the tips ( Fig 4a, f ). Four crescentric gastric phacellae, 1 in each corner of the shallow stomach, each with 6–24 basal trunks branching several times at the base, giving rise to up to 100 terminal filaments (gastric cirri) in larger specimens ( Fig 1f, g ; 4a, b, d–g ). Smaller individuals (BH< 20 mm ) possessing long filaments (6–8 basal trunks) extending from each corner into the stomach, giving appearance of a central mass ( Fig 4c ). Eight narrow leaf–like gonads extend in pairs within the gastric pockets, along either side of the interradial septa; filled with developing sperm or eggs in mature males and females ( Fig 4d, g, h ). We examined preserved individuals with gonads (BH = 16– 61 –100, BW = 6– 23 –34, n = 23), as well as preserved medusae without gonads (BH = 8– 32 –88, BW = 5– 15 –32, n = 22). All medusae <BH = 16 mm lacked gonads, as did many larger medusae (n = 18). Gonads presumably are shed in mature medusae following a spawning event (see Arneson 1976). Gonads, translucent in live medusae ( Fig 4g ; 6a, b ), turning cream to pale amber in spawning medusae; and opaque in fixed material. Ripe gonads overlap along the perradial plane, becoming increasingly pleated ( Fig 4g ). Cnidome Table 1; Fig 5a–h . Nematocyst measurements are provided as min– mean –max; L = length of capsule in µm, W = width of capsule at widest point in µm, SD = standard deviation, n = number of nematocysts measured. Nematocyst identification follows Mariscal (1974) , Östman (2000) , and Collins et al. (2011) .