Malmgreniella puntotorensis Pettibone 1993

Malmgreniella puntotorensis

MATERIAL EXAMINED.—NORTHWESTERN ATLANTIC OCEAN: Florida: Looe Key, back reef, 24°33′N, 81°24′W, sta LK-33,12 May 1985,4 m, sand, Thalassia, few sponges, on ophiuroid, G. Hendler, collector, paratype (USNM 133590).

CARIBBEAN SEA: Panama: Punto Toro, Fort Sherman, sta 147–1, 16 Apr 1973, sand bottom between rocks and Thalassia, M.L. Jones, collector, holotype (USNM 71760) and paratype (USNM 71761). Galeta Reef, 9–11 m, with burrowing ophiuroid Amphiodia trychna H.L. Clark, G. Hendler, collector: 27 Oct 1977, paratype (USNM 133588); 13 Sep 1978, paratype (USNM 133589); 3–5 Oct 1980, 3 paratypes (USNM 133586; LACM); 3 Oct 1980, on Ophiophragmus septus (Lütken), paratype (USNM 133587). Belize: Twin Cays, 16°50′N, 86°06′W, 0–2 m, 30 May 1983, on Ophionephthys limicola Lütken, G. Hendler, collector, paratype (USNM 133592). Twin Cays, Gator Creek, 1.5 m, 20 Jun 1985, on Ophiophragmus pulcher H.L. Clark, 3 paratypes (USNM 133596; LACM). Twin Cays, Hidden Creek, 1.5 mm, G. Hendler, collector, on Ophiophragmus pulcher, 30 May 1982, paratype (USNM 133591) and 23 Mar 1983, paratype (LACM); sta 85–11, 18 Jun 1985, 2 paratypes (USNM 133594); sta 85–12, 19 Jun 1985, 3 paratypes (USNM 133595, LACM); sta 86–7, 4 Apr 1986, 2 paratypes (USNM 133597); sta 89–14, 5 Mar 1989, paratype (USNM 133602); sta 89–22, 7 Mar 1989, paratype (USNM 133599); sta 89–25, 9 Mar 1989, paratype (USNM 133601); sta 89–31, 12 Mar 1989, 2 paratypes (USNM 133598); on Ophiophragmus cubanus (A.H. Clark), sta 85–12, 19 Jun 1985, paratype (LACM); sta 89–25, 9 Mar 1989, paratype (USNM 133600); on Amphiodia trychna, sta 85–11, 18 Jun 1985, paratype (USNM 133593).

DESCRIPTION.—Holotype (USNM 71760), female with eggs, 7.5 mm long, 2.5 mm wide including setae, with 34 segments; paratype (USNM 71761), male with sperm, 6.5 mm long, 2.5 mm wide, with 34 segments. Additional paratypes from Panama and Belize with 25–36 segments, 4–11 mm long, and 2–3 mm wide.

Body of type specimens from Panama without color; on specimens commensal with ophiuroids from Belize, color variable: body and elytra without color; uniformly reddish brown, darker on antennae, tentacular cirri, and mouth area (Figure 37A,B); some with anterior half or two-thirds of body dark and posterior region colorless; some with additional chalky white transverse segmental patches on middorsum and scattered spots on dorsal tubercles, cirrophores of dorsal cirri, on midventral groove and ventral bases of parapodia, and cirrophores of ventral cirri. Elytra 15 pairs, large, oval, overlapping, covering dorsum, delicate, opaque, granular, denser around place of attachment to elytrophores, without papillae or tubercles (Figures 36B, 37C,D).

Bilobed prostomium with anterior lobes truncate, without peaks; 2 pairs of eyes, anterior pair slightly anterior to greatest width, posterior pair near posterior border; median antenna with ceratophore in anterior notch, with style about 1.5 times longer than prostomium; lateral antennae with ceratophores inserted terminoventrally, converging midventrally, with short subulate styles; palps stout, tapered; tentaculophores without setae, with dorsal and ventral tentacular cirri similar to median antenna (Figures 36A, 37A,B). Segment 2 with first pair of elytrophores, subbiramous parapodia and long ventral buccal cirri on cirrophores lateral to ventral mouth, with styles similar to tentacular cirri (Figures 36A, 37A,B). Extended pharynx with 9 pairs of border papillae and 2 pairs of jaws.

Parapodium subbiramous; notopodium small, digitiform, on anterodorsal side of larger neuropodium; neuropodium with conical presetal acicular lobe, without supraacicular process and shorter, rounded postsetal lobe (Figures 36C,D, 37E,F). Notosetae reduced to 1–2, short, smooth, acicular, with pointed tip, not extending beyond tip of notopodium and easily overlooked (Figures 36C,E, 37E–G). Neurosetae rather few (about 11), forming fan-shape bundle; upper and middle neurosetae with longer spinose regions and bifid tips, with long secondary tooth (Figures 36F, 37H); lower neurosetae with shorter spinose regions, with small secondary tooth, 3–4 lowest neurosetae with secondary tooth very small or absent (Figures 36G, 37I). Dorsal cirri with cylindrical cirrophores, bulbous basally, with styles smooth, tapering, and extending to tips of neurosetae or beyond; dorsal tubercles bulbous; ventral cirri short, tapered (Figures 36D, 37F). Small pygidium posterior to last segment, with pair of anal cirri.

BIOLOGY.—Malmgreniella puntotorensis was collected by G. Hendler on Galeta Reef, Panama, and at Belize on five species of burrowing amphiurid ophiuroids: Amphiodia trychna H.L. Clark (7 specimens), Ophionephthys limicola Lütken) (1), Ophiophragmus cubanus (A.H. Clark) (2), Ophiophragmus pulcher H.L. Clark (17), and Ophiophragmus septus (Lütken) (1). The commensal polynoid was found by Hendler on the disc of a freshly excavated O. pulcher and, when the ophiuroid was allowed to burrow again in the sediment a couple of times, the polynoid remained attached to the disc of the brittle star. See color photos (Frontispiece B–D).

ETYMOLOGY.—The species is named for Punto Toro, the type locality.

DISTRIBUTION.—Northwestern Atlantic Ocean, Caribbean Sea, Florida (Looe Key), Panama, Belize. Intertidal to 11 meters.