English: Anatomical and morphological details of Habelia optata, morphs A (b, d, f, n) and B (a, e, g, i, l, m). a USNM 139209, close-up of anterior cephalic area, showing intermediary appendage. b USNM 268931, cephalon, showing superimposed insertion of endopods on gnathobases; star points to insertion of anterior endopods. c ROMIP 64357, close-up of fourth cephalic exopodial branch, distal portion showing slender podomeres; arrow points to trident of setae at podomere junction. d ROMIP 64358, close-up of anteriormost region, showing mouth opening and first anterior pairs of gnathobases. e ROMIP 64360, close-up of teeth on masticatory margin of gnathobase; note heavy concentration of carbon in teeth. f Close-up of teeth on masticatory margin of posterior gnathobase on same specimen as in D, showing stronger carbon content in dental edge. g ROMIP 64364, specimen preserved in ventral aspect, close-up of anterior region showing labrum, eyes and appendages; star marks attachment of fifth spinose endopod; arrow points at ornamental spine of cephalic pleura; insets as indicated. h ROMIP 64362, close-up of posterior trunk exopods. i ROMIP 64363, close-up of anterior right cephalic region, dorsal view showing labrum and appendages; arrows point to overprint of gnathobases underneath cephalon. j, k ROMIP 64364. j Close-up of distal portion of cephalic endopod, showing “platform” with setal brushes. k Close-up of terminal claw; arrows point to teeth on inner margin of claw. l USNM 144907, close-up of cephalic gnathobases; arrows point to dentate margins of opposing gnathobases. m ROMIP 64357, close-up on anterior left cephalic region, showing appendages; arrow points to anterior insertion of fourth cephalic endopod. n ROMIP 64359, close-up of cephalic appendages showing insertion of endopods on gnathobases; star marks attachment of fourth cephalic endopod on its gnathobase. c-f, j and k are SEM images; all other are stereomicroscope images of dry specimens under cross-polarized lighting. For abbreviations, see Methods. Scale bars: (a, g, h, i, l, n), 1 mm; (b, m), 0.5 mm; (c, d, k), 200 μm; (e), 100 μm; (f), 50 μm; (j), 500 μm