Fig. 1

a-h Morphology of A. alata mature female medusa similar to that collected and subsampled for de novo transcriptome assembly in this study. White boxes correspond to the location of medusa body parts sub-sampled. a Mature A. alata medusa (live). b A portion of a gastric phacella removed from a live medusa, with five individual gastric cirri. c Ovulation documented within the female gastrovascular cavity; arrow indicates imminent release of teardrop shaped ovum. d Interaction between recently ovulated egg and spermatozoa (arrows) in the fluid examined from the gastrovascular cavity (representing putative fertilization). e Intact nematocysts (euryteles with associated filaments) on the left, and a discharged eurytele on the right, isolated from the tentacle. f Rhopalium connected to the rhopaliar stalk showing upper and lower lens eyes, and lateral pit and slit eyes (one of each pair visible). g Bundles of blastulae released by females entangled in fibrous material and intact eurytele nematocysts. h Swimming planula (within 20 h of blastula release from the female); arrows indicating planulae eyes spots. Abbreviations: cap = capsule of nematocyst; em = embryos; fil = filaments; fm = fibrous material, gc = gastric cirri; gp = gastric phacella (comprised of numerous gastric cirri); nem = nematocyst (birhopaloids)s; ov = ovum (ova); ovr = ovaries; pe = pit eye; ped = pedalium; rp = rhopalium; rps = rhopaliar stalk; se = slit eye; sp = sperm; sft = shaft of nematocyst tubule; spn = spines of nematocyst shaft; tb = tubule of discharged nematocyst; tnt = tentacle. Scale bars: a = ~15 mm, b = ~0.5 mm, c = ~250 μm, d = ~30 μm, e = ~20 μm, f = ~0.2 mm, g = ~100 μm, h = ~30 μm