Malmgreniella variegata (Treadwell 1917)

Malmgreniella variegata (Treadwell, 1917)

Harmothoe variegata Treadwell, 1917:260, pl. 1: figs. 17, 18; pl. 2: figs. 1–3.—Hartman, 1956:251, 265, 273.

Paralepidonotus boholensis Gr. var. curacaoensis Horst, 1922:198.

Malmgrenia curacaoensis.—Augener, 1927:45, fig. 2A–D.—Kudenov, 1975b:79.

Harmothoe lunulata.—Millott, 1953:96, figs. 1, 2 [not Delle Chiaje, 1830].

Harmothoe sp.—Hanley, 1987:156.

MATERIAL EXAMINED.—NORTHWESTERN ATLANTIC OCEAN: Florida: Gulf of Mexico, Dry Tortugas, Jun-Jul 1909, holotype of Harmothoe variegata (AMNH 971). Straits of Florida, Looe Key, 24°33′N, 81°24′W, on brittle star Ophionereis reticulata (Say), G. Hendler, collector, by scuba: sta LK-1, 28 Aug 1984, fore reef spur and groove coral reef, 7 m, 1 specimen (USNM 133579; color photo by J.E. Miller); sta LK-33,12 May 1985, back reef, 4 m, 1 small specimen (USNM 133578); sta LK-53, 16 Aug 1985, near northeastern core marker, 2–3 m, 1 specimen (LACM).

CARIBBEAN SEA: Belize: Norval Cay, on Ophionereis reticulata, G. Hendler, J. Miller, collectors, 1.5 m, sta 89-11,4 Mar 1989, 2 specimens (USNM 133576). Curaçao: “Spaansch water,” in Porites porites, 10 Apr 1920, van der Horst, collector, 3 syntypes of Paralepidonotus boholensis var. curacaoensis (ZMA 1039; as Malmgrenia curacaoensis by Augener, 1927, and as Harmothoe sp. by Hanley, 1987). Piscadera Beach, adjacent to Caribbean Marine Biological Institute, sand and rubble, 25 Sep 1976, M.L. Jones, collector, 1 specimen (USNM 133580).

EAST PACIFIC OCEAN: Pamama: Gulf of Panama, Perlas Islands, Pedro Gonzales, on Ophionereis annulata (Le Contel), low water, under stones in coarse sand, 26 Apr 1976, S. Oldfield, collector, 2 specimens (USNM 133577).

DESCRIPTION.—Holotype of Harmothoe variegata from Dry Tortugas (AMNH 971) 26 mm long, 7 mm wide including setae, with 39 segments and 15 pairs of elytra. Complete syntype of Paralepidonotus boholensis var. curacaoensis from Curaçao (ZMA 1039) 18 mm long, 7 mm wide, with 39 segments and 15 pairs of elytra. Specimen from Curaçao (USNM 133580) 24 mm long, 7 mm wide, with 40 segments; largest specimen from Looe Key (USNM 133579) 24 mm long, 7 mm wide, with 40 segments. Young specimen from Looe Key (USNM 133578) 4 mm long, 2 mm wide, 22 segments with small posterior end, short anal cirri, and 11 pairs of elytra. Specimen on Ophionereis reticulata from Belize (USNM 133576) 23 mm long, 7 mm wide, with 38 segments. Two specimens on O. annulata from Gulf of Panama (USNM 133577), one incomplete with elytra, 11 mm long, 4 mm wide, with 32 segments; complete one with elytra missing, 13 mm long, 5 mm wide, with 40 segments, last one very small.

Body elongated, flattened, with sides nearly parallel, tapering posteriorly. Striking black or brown markings on elytra; on dorsum with small marks beginning on middle of body, becoming wider bands on posterior fourth (Figure 30B); on ventrum along midventral groove, on lateral bases of parapodia, and on ventral cirri (Figure 30C); and anteriorly on upper, lateral, and posterior lips of ventral mouth (Figure 29B). Transverse ciliated bands on dorsum, 2 per segment, between elytrophores and dorsal tubercles (Figures 28A, 29A). Fifteen pairs of elytra, covering dorsum except for few posterior segments. Elytra oval to subreniform, without papillae, with group of microtubercles near anterior borders (absent on first and some posterior elytra); pigmentation denser in some areas, consisting of wide funnel-shape area on posterior half of elytra, radiating from region of attachment to elytrophore to medial-posterior part, continuing as narrow band along posterior-lateral border, then to narrow transverse band completing the circle (Figures 28B,C, 30D–F; Treadwell, 1917, pl. 1: fig. 17; Augener, 1927, fig. 2A).

Bilobed prostomium with anterior lobes truncate or subtriangular, without distinct peaks, with 2 pairs of rather small eyes, anterior pair anterior to widest part of prostomium, posterior pair near posterior border, large ceratophore of median antenna in anterior notch, with long style; ceratophores of lateral antennae inserted terminoventrally, converging midventrally and with ciliated ridge on ventral side, and short styles; palps stout, tapered, with longitudinal rows of minute papillae; tentaculophores each with small projecting acicular lobe on inner side, without setae, and pair of dorsal and ventral tentacular cirri similar to median antenna; all appendages variously pigmented (Figures 28A, 29A,B, 30A, 31A; Treadwell, 1917, pl. 1: fig. 18). Segment 2 with first pair of elytrophores, biramous parapodia, and ventral buccal cirri with large cirrophores lateral to ventral mouth and long styles similar to tentacular cirri (Figures 28A,D, 29A,B, 30A). Notosetae similar to those of following segments; neurosetae slender, curved, tapering to fine blunt tips (Figure 28D–F).

Parapodia biramous, with notopodia shorter than neuropodia; notopodium rounded with projecting acicular lobe on lower side; larger neuropodium with longer subconical, presetal acicular lobe with bulbous or digitiform supraacicular process, with shorter, rounded postsetal lobe (Figures 28G,H, 30G,H, 31B,C; Treadwell, 1917, pl. 2: fig. 2). Notosetae numerous, forming radiating bundle, stouter than neurosetae, with numerous, faint, close-set spinose rows, shorter notosetae with tapered tips, longer ones with blunt tips (Figures 28E,I, 30I, 31D; Augener, 1927, fig. 2B). Neurosetae numerous, forming fan-shape bundle, with numerous, faint, close-set spinose rows, tapering distally to slightly hooked tips, all, except for some lower shorter neurosetae, with secondary tooth (Figures 28J,K, 30J,K, 31E,F; Treadwell, 1917, pl. 2: fig. 3; Augener, 1927, fig. 2C, D). Dorsal cirri with cylindrical cirrophores and long styles extending beyond neurosetae, with 2 dark bands near tip; dorsal tubercles nodular, ventral cirri short, tapered (Figures 28H, 30H, 31C). Pygidium with anus between last pair of small parapodia, with pair of long anal cirri, color grading from darkly pigmented to colorless distal tips.

BIOLOGY.—Norman Millott (1953, figs. 1,2) described and published photographs of two polynoids, one wrapped around the aboral disc of the banded ophiuroid Ophionereis reticulata (Say), the other crawling along the arm of another individual, all found in sand beneath a submerged stone near Kingston, Jamaica. The polynoids showed a color pattern matching closely that of the brittle stars. Although the specimens were not available for study, the polynoids, identified as Harmothoe lunulata, are considered herein to be Malmgreniella variegata. On Looe Key, two adults and one young specimen of M. variegata were collected by scuba in 2–7 meters on specimens of O. reticulata by Gordon Hendler and John Miller. The adults showed the characteristic color pattern (Figure 30A–H; Frontispiece). The young polynoid was nearly colorless, only showing color markings on some anterior elytra and spots on the lower lip (Figure 31). On the Perlas Islands, Gulf of Panama, two specimens of M. variegata were collected on Ophionereis annulata (Le Conte) under stones in coarse sand by Susan Oldfield (in litt.). On Norval Cay, Belize, G. Hendler (in litt.) observed a good number of Ophionereis reticulata. When turning over a piece of coral rubble that was sheltering two ophiuroids, a polynoid, identified later as M. variegata, was found on the rock between them, suggesting that the polynoids move on and off their hosts. According to G. Hendler (in litt.), both O. annulata and O. reticulata, the hosts of M. variegata, have similar pigmentations and color patterns, both have banded arms. See Frontispiece.

DISTRIBUTION.—Northwestern Atlantic Ocean, off Florida; Gulf of Mexico; Caribbean Sea; East Pacific Ocean, Gulf of Panama. Intertidal to 7 meters.