Myzostoma eeckhauti, 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 : 312

Myzostoma eeckhauti n. sp. Summers & Rouse

Fig. 4 D–G

Holotype: SIO-BIC A4013 paragenophore (1 spm: 95% ethanol). Madang Harbor, Papua New Guinea (5° 13.200'S, 145° 48.879'E), 5– 20 m. Collected at night using scuba on 7 December 2012 by MMS and GWR.

Host. Dichrometra / Lamprometra / Liparometra sp. 1 (Müller) (Crinoidea, Comatulida , Mariametridae ). SIO- BIC E5913 (tissue subsample in 95% ethanol).

Paratypes: SIO-BIC A3668 paragenophores (15 spms: 1—in 70% ethanol after formalin fixation; 13—95% ethanol; 1—mounted for SEM). Same host and locality as holotype. Genbank (COI—KM014192). SIO-BIC A3667 syngenophores (6 spms: 95% ethanol). Same locality as holotype. Host. Dichrometra / Lamprometra / Liparometra sp. 1. MNHN-IE-2013-8128 (dried voucher) & SIO-BIC E5912 (tissue subsample in 95% ethanol). Genbank (COI—KM014351).

Etymology. Named after Igor Eeckhaut, for his extensive contributions to our understanding of myzostomid biology and systematics.

Diagnosis and description. Holotype body elongate, terminating in 6 cylindrical caudal processes ( Fig. 4 D–E). Length ~ 2.5 mm (including caudal processes), width ~ 1 mm following fixation. Medialmost pair of caudal processes longest; outermost pair shortest. Body margin with 20 cirri, most anterior pair more than three times as long as rest, which are short, triangular. Short cirri on some caudal processes, others acirrate. Mouth and cloaca terminal, cloaca located between caudal processes. Extended proboscis smooth ( Fig. 4 F). Five pairs of parapodia, midway between midpoint and body-margin with hooks ( Fig. 4 G). Live color pink, white in preservative.

Remarks. Four other species are known with 6 caudal processes ( Table 1). Two have caudal processes with cirri as in Myzostoma eeckhauti n. sp. Myzostoma intermedium Graff, 1884 was described from a badly damaged specimen collected on Zygometra microdiscus (Bell) in the Torres Strait. A specimen very similar to the description and drawing in Graff (1884) was collected from the same host species in Lizard Island, Australia (Accession: SIO- BIC A4017). This specimen has a circular body with 20 long marginal cirri and six caudal processes with very long cirri—all features which distinguish it from Myzostoma eeckhauti n. sp. DNA sequences were not amplified from this specimen. Myzostoma jaegersteni Eeckhaut et al. 1994 also possesses caudal processes with cirri. It was described from Heterometra savignii (Müller) from Johore Shoal, Singapore, and specimens assigned to this species by the authors were also found on Neometra multicolor (AH Clark) and Tropiometra carinata (Lamarck) . All identified specimens were dredged, presumably from deeper waters. We collected specimens of a similar size and color (thin and translucent), but from a different host— Dichrometra flagellata —from Lizard Island, Australia. Although we expect these to be a different species from those described in Singapore, we refer to these specimens as Myzostoma cf. jaegersteni . Myzostoma eeckhauti n. sp. can be distinguished from Myzostoma cf. jaegersteni by molecular data, host use, and general appearance ( M. eeckhauti n. sp. is thick and pink).

Figures

FIGURE 4. (A – B) Live photographs of Myzostoma debiae n. sp. paratype (SIO-BIC A 3794) — (A) dorsal, showing characteristic color and patterning; (B) ventral, extended penises adjacent to third pair of parapodia and extended proboscis with seven papillae. (C) Live photograph of Myzostoma miki n. sp. holotype (SIO-BIC A 3662), dorsal, unique honeycomb pattern shown. (D – G) Myzostoma eeckhauti n. sp. paratypes (SIO-BIC A 3668) — (D) dorsal; (E – G) SEM, (E) ventral, specimen with only three pairs of parapodia—all other types had five pairs; (F) smooth extended proboscis, (G) parapodia with hook. (H – I) Live photograph of Myzostoma hollandi n. sp. holotype SIO-BIC A 3791 — (H) dorsal; (I) ventral, showing six acirrate caudal processes and eight distinctive anterior triangular cirri. (J – K) Live photographs of Myzostoma indocuniculus n. sp. paratypes (SIO-BIC A 3763) — (J) dorsal showing two wide bunny ear-shaped caudal processes; (K) from the side, showing the cirri on the body margin and their relative lengths. Scalebars 2 mm (A-B); 1 mm (C – E, H – K); 100 Μm (F, G).