Myzostoma pipkini, 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 : 318-319

Myzostoma pipkini n. sp. Summers, Al-Hakim & Rouse

Fig. 6 A–I

Hypomyostoma n. sp. 1— Lanterbecq et al. (2006).

Holotype: MZB Pol. 0 0 130 paragenophore (1 spm: in 70% ethanol after formalin fixation). New Reef, Raja Ampat, Indonesia (0°32'40.44"S, 130°41'39.52"E), less than 20 m. Collected using scuba on 20 October 2013 by MMS and GWR.

Host. Colobometra perspinosa (Carpenter) ( Colobometridae , Comatulida , Crinoidea). Genbank (COI—KM491783).

Paratypes: SIO-BIC A4018 paragenophore (1 spm: 95% ethanol). Same host and locality as holotype. Genbank (COI—KM491752). AM-W.43459 syngenophores (4 spms: in 70% ethanol after formalin fixation), AM-W.43460 syngenophore (1 spm: in 70% ethanol after formalin fixation), AM-W.43460 syngenophore (1 spm: 95% ethanol), and AM-W.43452 syngenophores (18 spms—95% ethanol). West of Dili, off Tibar, Banda Sea, Timor-Leste (8°33'47"S, 125°28'31"E), 4– 10 m. Collected using scuba on 21 Sep 2012 by GWR and Nerida Wilson. Genbank (COI—KM491753; KM491754 ). Host: Colobometra perspinosa , AM-J.25415; Genbank (COI—KM491784). SIO-BIC A3753 syngenophore (1 spm: 95% ethanol). West Mansuar, Raja Ampat, Indonesia (0°36'30.10"S, 130°32'37.53"E), less than 20 m. Collected using scuba on 23 October 2013 by MMS and GWR. Genbank (COI—KM491755). Host: Colobometra perspinosa , SIO-BIC E6151. SIO-BIC A3818 syngenophores (3 spms: 1 spm—in 70% ethanol after formalin fixation; 1 spm—95% ethanol; 1 spm—mounted for SEM). Cobia Hole, Lizard Island, Australia (14°39'6.9834"S, 145° 27' 30.9954"E), 18 m. Collected using scuba on 21 March 2000 by GWR. Genbank (COI—KM491756). Host: Colobometra perspinosa . SIO-BIC A3742 syngenophores (4 spms: 3 spms—in 70% ethanol after formalin fixation; 1 spm—95% ethanol). New Reef, Raja Ampat, Indonesia (0°32'40.44"S, 130°41'39.52"E), less than 20 m. Collected using scuba on 20 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6152; Genbank (COI—KM491785). SIO-BIC A3743 syngenophores (2 spms: 1½ spm—in 70% ethanol after formalin fixation; ½ spm—95% ethanol). New Reef, Raja Ampat, Indonesia (0°32'40.44"S, 130°41'39.52"E), less than 20 m. Collected using scuba on 20 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6153. SIO-BIC A3745 syngenophores (2 spms: 1½ spm—in 70% ethanol after formalin fixation; ½ spm—in 95% ethanol following DMSO fixation). Citrus Reef, Gam Island, Raja Ampat, Indonesia (0°32'20.34"S, 130°36'4.13"E), less than 20 m. Collected using scuba on 21 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6154. SIO-BIC A3746 syngenophores (2 spms: 1 spm—in 70% ethanol after formalin fixation; 1 spm—in 95% ethanol after DMSO fixation). Yenbuba Jetty, eastern side of Mansuar, Raja Ampat, Indonesia (0°34'18.30"S, 130°39'30.28"E), less than 20 m. Collected using scuba on 13 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6155. SIO-BIC A3747 syngenophore (1 spm: ½ spm—in 70% ethanol after formalin fixation; ½ spm—95% ethanol). Sorido Blue Hole, Raja Ampat, Indonesia (0°33'28.19"S, 130°41'37.90"E), less than 20 m. Collected using scuba on 19 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6156. SIO-BIC A3751 syngenophore (1 spm: 95% ethanol). Otdima Reef, Raja Ampat, Indonesia (0°32'59.70"S, 130°37'10.88"E), less than 20 m. Collected using scuba on 22 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6157; Genbank (COI—KM491786). SIO-BIC A3755 syngenophore (1 spm: ½ spm—in 70% ethanol after formalin fixation; ½ spm—95% ethanol). New Reef, Raja Ampat, Indonesia (0°32'40.44"S, 130°41'39.52"E), less than 20 m. Collected using scuba on 20 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6162. SIO-BIC A3756 syngenophores (2 spms: 1 spm—in 70% ethanol after formalin fixation; 1 spm—95% ethanol). Otdima Reef, Raja Ampat, Indonesia (0°32'59.70"S, 130°37'10.88"E), less than 20 m. Collected using scuba on 22 October 2013 by MMS and GWR. Host: Colobometra perspinosa , SIO-BIC E6158.

Etymology. Named for Jason Pipkin , an explorer of annelid neuroanatomy.

Diagnosis and description. Holotype body elongate, terminating in a point posteriorly ( Fig. 6 A–C, G–I).

Length ~ 1.2 cm following fixation. Body margin scalloped, composed of many irregularly-sized triangular cirri. Mouth and cloaca on ventral surface. Mouth subterminal, positioned midway between first pair of parapodia and body margin. Extended proboscis smooth ( Fig. 6 C, I). Five pairs of parapodia with small, low cirri and hooks ( Fig. 6 D–E) restricted to the anterior half of the body ( Fig. 6 C, I). Cloaca positioned midway between last pair of parapodia and body margin. Paired penes in line with third pair of parapodia. Small lateral organs, alternating with parapodia. Dorsal surface with longitudinal ridge and 12 lateral ridges, of which the four most anterior are not continuous.

Remarks. Myzostoma pipkini n. sp. is most similar to Myzostoma attenuatum Grygier, 1989 , Hypomyzostoma folium ( Graff, 1884a) , Hypomyzostoma nanseni ( Graff, 1887) , and Myzostoma moebianum ( Graff, 1884a) . These taxa are elongate with the posterior end terminating in a point and have a scalloped margin composed of many irregularly shaped cirri, subterminal mouth, and the cloaca and parapodia restricted to the anterior two-thirds of the body.

Myzostoma attenuatum was described from the Philippines associated with Capillaster sentosus (Carpenter) , with paratypes from a variety of other hosts distributed throughout the Indo-Pacific ( Comaster multifidus (Müller) , Colobometra perspinosa, Oxymetra finschii (Hartlaub), Pontiometra andersoni (Carpenter) , Decametra mylitta AH Clark, Cenometra bella (Hartlaub) , Stephanometra indica (Smith) , Phanogenia gracilis (Hartlaub) , Petasometra helianthoides AH Clark). Myzostoma attenuatum was suggested as a possible synonymn of M. moebianum in Grygier (1989, 1992). Myzostoma moebianum was described from a poorly preserved specimen collected at Fouquet Island ( Seychelles) on an unknown feather star host (referred to as Comatula sp.). In M. moebianum the skin is ciliated (not mentioned in descriptions of M. attenuatum ). Specimens assignable to M. attenuatum (or M. moebianum —dorsal cilia present) were collected and sequenced in Summers & Rouse (2014). These specimens were associated with three hosts ( Cenometra bella , Petasometra clarae (Hartlaub) , and Pontiometra andersoni ), confirming the wide range of recorded hosts included in the original descriptions for M. attenuatum (see Genbank KM014182 ; KM491757 ; KM491758 ; KM491759 ; KM491760 ; KM491761 ; KM491762 ). Myzostoma pipkini n. sp. is distinguished from M. attenuatum / M. moebianum by molecular data, lack of cilia on the dorsal surface, parapodia midway between the midline and margin (in M. attentuatum the parapodia are closer to the margin), and a continuous scalloped margin (the cirri are sparse in the posterior region of M. attenuatum ).

Hypomyzostoma folium was described from southwest of West Papua, Indonesia associated with Cyllometra manca (Carpenter) . Hypomyzostoma folium differs from M. pipkini n. sp. by having a distinctive elevated longitudinal ridge, lacking lateral organs, and occupied host. Hypomyzostoma nanseni was described from the Maluku Islands, Indonesia found lying loose with a collection of feather stars. This species was distinguished by a dorsal line along the mid-line and the color was recorded as a uniform dirty brown and reddish. A specimen matching this description was collected from Basilometra boschmai AH Clark and sequenced in Summers & Rouse (2014). We suggest that the host now be considered Basilometra boschmai for this species. The cirri of these specimens were cylindrical, more elongate, and spaced apart, of a much different appearance than the scalloped margin of M. pipkini n. sp. These specimens also possessed a wide dorsal ridge above the intestinal track, which is not present in M. pipkini n. sp.

Myzostoma pipkini n. sp. can be further distinguished from all of these taxa by the horizontal ridges on the dorsal surface, which ranges among types from approximately seven to 12. The live dorsal coloring of M. pipkini n. sp. varies from white and black ( Fig. 6 F–G), white-green ( Fig. 6 H–I), and red, with or without white patterning (not shown). In preservative, colors are faded or mostly white. Length of types 1 mm— 1.2 cm.

Figures

FIGURE 6. (A – I) Myzostoma pipkini n. sp. — (A – E) SEM of paratype (SIO-BIC A 3818), (A – B) dorsal, showing transverse ridges and scalloped margin, (C) ventral showing smooth extended proboscis, five pairs of parapodia restricted to anterior twothirds of body, and position of cloaca midway between last pair of parapodia and body margin, (D) hook within parapodia, (E) two parapodia with small cirrus buds, indicated by arrow head; (F – I) live photographs, (F – G) paratype SIO-BIC A 3746, dorsal view on host Colobometra perspinosa (F) and separated, showing transverse ridges and scalloped margin (G), (H – I) paratype (SIO-BIC A 3755), (H) dorsal view, (I) ventral, showing smooth proboscis, restricted parapodia, and position of cloaca. (J – M) Live photographs of Myzostoma susanae n. sp. holotype (SIO-BIC A 3803), (J, M) on host, Comaster schlegelii, (K) dorsal view, a few small cirri visible on body margin, (L) ventral view showing five pairs of parapodia, indicated with an arrow head, and alternating lateral organs, anus (a) and pharynx (ph). (N – P) Live photographs of Myzostoma tertiusi n. sp. holotype (SIO- BIC A 3793) — (N) on host, Colobometra perspinosa, (O) dorsal view showing color pattern and scalloped margin, (P) ventral view showing five pairs of parapodia and smooth extended proboscis. Scalebars 2 mm (J-M); 1 mm (N – P); 0.5 mm (A – C, F – I); 200 Μm (E); 20 Μm (D).