Hypomyzostoma jasoni, Summers, Mindi M., Al-Hakim, Iin Inayat & Rouse, Greg W., 2014

Summers, Mindi M., Al-Hakim, Iin Inayat & Rouse, Greg W., 2014, Turbo-taxonomy: 21 new species of Myzostomida (Annelida), Zootaxa 3873 (4), pp. 301-344 : 308

Hypomyzostoma jasoni n. sp. Summers & Rouse

Fig. 3 A–F

Hypomyzostoma crosslandi B—Lanterbecq et al. (2006)

Holotype: SIO-BIC A4020 (1 spm: 95% ethanol). South Wongat Reef, Madang Harbor, Papua New Guinea (5°8'25.8"S, 145°49'22.7928"E), <20 m. Collected using scuba on 29 November 2012 by MMS and GWR. Genbank (COI—KM491745).

Host. Stephanometra indica (Smith) ( Mariametridae , Comatulida , Crinoidea). MNHN-IE-2013-8125 (dried voucher) & SIO-BIC E5883 (tissue subsample in 95% ethanol). Genbank (COI—KM491776).

Paratypes: SIO-BIC A3702 paragenophores (2 spms: 1—in 70% ethanol following fixation in formalin; 1 spm—95% ethanol). Same host and locality. Genbank (COI—KM491746). SAM E3398 syngenophores (3 spms: 1—in 70% ethanol following fixation in formalin; 1 spm—95% ethanol; 1 spm—mounted for SEM). Horseshoe Reef, Lizard Island, Australia (14°41'12.2"S, 145°26'31.4"E), 3 m. Collected using scuba on 17 November 2001 by GWR. Genbank (COI-DQ238198). Host: Stephanometra indica , SAM K2030.

Etymology. Named for Jason Rouse , brother of GWR, in honor of his birthday.

Diagnosis and description. Holotype body elongate, rounded anteriorly and posteriorly. Length ~ 6 mm following fixation. Body margin dentate, composed of many triangular cirri ( Fig. 3 B–E). Mouth and cloaca on ventral surface, subterminal ( Fig. 3 D). Extended proboscis smooth. Five pairs of parapodia with small, low cirri and hooks restricted to the anterior 3/5 of the body. Paired penes in line with third pair of parapodia. Small lateral organs, alternating with parapodia. Dorsal surface smooth ( Fig. 3 E). Color in life and preserved white with ten thick, dark transverse lines.

Remarks. Hypomyzostoma jasoni n. sp. is most similar to H. crosslandi ( Boulenger, 1913) , H. elongatum ( Graff, 1887) and H. jonathoni n. sp. —taxa with a scalloped or dentate margin from numerous cirri, rounded anterior and posterior margin, and smooth dorsal surface with transverse bands of a different color ( H. crosslandi and H. jonathoni n. sp.). Hypomyzostoma crosslandi was described from the Sudanese coast of the Red Sea associated with Heterometra savignii (Müller) , Oligometra serripinna (Carpenter) , and an unknown Comatulida . Hypomyzostoma elongatum was described from the Philippines, found on Comanthus parvicirrus (Müller) . Hypomyzostoma jonathoni n. sp. (see below) is associated with Liparometra articulata (Müller) . The location of the cloaca in H. jasoni n. sp., approximately two-thirds of the way between parapodia and body margin, differs from both H. jonathoni n. sp., H. elongatum , and H. crosslandi which have clearly subterminal cloacae. Hypomyzostoma jasoni n. sp. is further distinguished based on host use, and for H. jonathoni n. sp., molecular data.

Other members of Hypomyzostoma have transverse ridges or other raised features on the dorsal surface, one of which, H. membranaceum ( Graff, 1887) was described from Stephanometra indica —the host of H. jasoni n. sp. The types of H. membranaceum have been lost, yet the description provides multiple features which allow it to be distinguished to H. jasoni n. sp. Hypomyzostoma membranaceum possesses longitudinal swellings and five pairs of oval prominences on the dorsal surface, does not have lateral organs, the color is noted to be uniform, and the drawings show a subterminal cloaca close to the margin and parapodia distributed evenly along the entire length of the body.

Figures

FIGURE 3. (A – B) Hypomyzostoma jasoni n. sp. — (A – C) live photographs, (A) non-type (SIO-BIC 4025) on arm of host Stephanometra indica, arrow indicating myzostomid; (B) paratype (SAM E 3398) side profile, showing scalloped margin; (C) paratype (SAM E 3398) dorsal view, showing transverse lines and extended, smooth proboscis; (D – F) SEM of paratype (SAM E 3398), (D) ventral, showing five pairs of parapodia restricted to anterior two-thirds of body and cloaca positioned between last pair of parapodia and body margin; (E) side view, showing smooth dorsal surface and scalloped margin; (F) parapodia with hooks and small cirri buds, indicated by arrowheads. (G – K) Hypomyzostoma jonathoni n. sp. — (G – H) SEM of paratype (SIO- BIC A 4024), (G) parapodia with hook, (H) side profile, showing parapodia with hooks and penis aligned with third parapodia; (I – K) live photographs of paratypes (SIO-BIC A 4026), (I) dorsal view showing transverse lines and smooth extended proboscis; (J) juvenile removed from cyst on arm of host, folded ventral side facing upwards; (K) side profile, showing scalloped margin and range of parapodia. Scalebars 1 mm (A-E); 0.5 mm (I-K); 0.25 mm (J); 100 Μm (F, H); 10 Μm (G) (J); 100 µm (F, H); 10 µm (G).