Myzostoma miki, 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 : 317

Myzostoma miki n. sp. Summers & Rouse

Fig. 4 C

Holotype: SIO-BIC A3662 hologenophore (1 spm: 95% ethanol). Wongat Island, Madang, Papua New Guinea (5° 8.093'S, 145° 49.338'E), less than 20 m. Collected using scuba on 4 December 2012 by MMS and GWR. Genbank (COI—KM491751).

Host. Clarkcomanthus luteofuscum HL Clark ( Comatulidae , Comatulida , Crinoidea). SIO-BIC E5951 (tissue subsample in 95% ethanol). Genbank (COI—KM491782).

Paratypes: SIO-BIC A3834 (2 spms: 95% ethanol). Hook Reef, Whitsunday Islands, Australia (20° 7'5.03"S, 148°55'25.30"E), 10 m. Collected using scuba on 22 June 2011 by GWR and Nerida Wilson. Genbank (COI—KM014201). Host: Clarkcomanthus luteofuscum , SIO-BIC E4726; Genbank (16S—KM491765).

Etymology. Named for Michael Summers, father of MMS.

Diagnosis and description. Holotype body circular, ~ 2 mm in diameter following fixation. Dorsal surface with elevated hexagonal ridges in 5 rings, resembling a honeycomb ( Fig. 4 C). Body margin with 20 short-medium length cirri, equal length. Mouth and cloaca on ventral surface, in line with parapodia. Proboscis with 9 papillae. Five pairs of parapodia midway between midline and body margin. Paired penes in line with third pair of parapodia. Four pairs of lateral organs midway between parapodia and body margin, alternating with the former.

Remarks. Myzostoma miki n. sp. can be distinguished from other shallow-water myzostomids by its hexagonal honeycombed ridged pattern on the dorsal surface ( Table 1). Two other species have been described with a pentagonal dorsal patterning. Myzostoma chelonium McClendon, 1906 and Myzostoma chelonoidium McClendon, 1906 were both described associated with the same host— Calometra discoidea Carpenter, 1888 —from the same locality—Suruga Gulf and Sagami Sea, Japan, and are possibly the same species. These specimens are described as circular and elongate, respectively, and drawings show two to three rings of large (relative to their dorsal surface) square to hexagonal combs (the author stated that they gave the appearance of a turtle shell) ( McClendon 1906). The two anterior and posterior pairs of cirri were observed to be smaller than the rest in M. chelonium —a feature not seen in Myzostoma miki n. sp. The difference in host, locality, and overall appearance of the pentagonal ridges allows separation of these two Japanese species from Myzostoma miki n. sp.

One species known to associate with Comatulidae may (or may not) have a complex dorsal patterning— Myzostoma atrum Atkins, 1927 . Myzstoma atrum was described from the Great Barrier Reef, associated with Comatula pectinata (Linnaeus) and another unidentified crinoid. This species has a dorsal surface that varied among specimens, likely due to poor preservation. One drawing depicts a specimen with many small ridges, similar to Myzostoma miki n. sp., but these ridges were described as irregular folds in the dorsal surface. Myzostoma atrum was also found on a different host, recorded as dark purple, and lacked marginal cirri—all features which distinguish it from Myzostoma miki n. sp.

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).