Paranaitis bowersi (Benham, 1927)

Kato, Tetsuya & Pleijel, Fredrik, 2003, A revision of Paranaitis Southern, 1914 (Polychaeta: Phyllodocidae), Zoological Journal of the Linnean Society 138 (4), pp. 379-429 : 391-395

PARANAITIS BOWERSI ( BENHAM, 1927)

Phyllodoce bowersi Benham, 1927: 77 , pl. 1, figs 27– 31; Monro, 1936: 111; Hartman, 1959: 160; Wesenberg-Lund, 1962: 40.

Phyllodoce (Anaitis) bowersi: Monro, 1930: 72–73 .

Anaitides bowersi: Hartman, 1964: 49 , pl. 15, figs 1, 2.

Anaitis bowersi: Uschakov, 1962: 140–141 , pl. 1, figs B–V.

Paranaitis bowersi: Averincev, 1972: 106 ; Uschakov, 1975: 148, fig. 1.

Material examined

Holotype ( BMNH 1928.2.29.13), Ross Sea, 284 m.

Description

Holotype complete specimen, c. 60 mm long, 4.7 mm wide, for 117 segments. Preserved specimen uniformly pale; live specimen pale pink ( Benham, 1927). Body dorso-ventrally flattened, of uniform width, with tapering posterior end. Prostomium anteriorly rounded, wider than long, with shallow but distinct ligula. Paired antennae and palps short, conical, directed laterally. Eyes absent. Nuchal papilla longer than diameter, situated posteriorly in ligula. Nuchal organs probably fully retracted in holotype, situated in lateral slit between prostomium and segment 1; shape unknown. Distal part of proboscis with six rows of rounded tubercles. Proximal part (less than 1/10 of total length) dorsally smooth, laterally and ventrally with c. 30 conical large papillae. Chitinous papillae probably absent. Terminal ring with c. 15 rounded well defined papillae. Paired large papillae present laterally inside ring.

Segments 1 and 2 fused. Cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3 cylindrical, long and tapered. Cirri of segment 1 and ventral cirri of segment 2 reaching c. segment 5. Dorsal cirri of segment 2 reaching c. segment 7. Dorsal cirri of segment 3 reaching c. segment 8. Segment 2 with small neuropodial lobes with c. 7 chaetae, lobes partly fused to ventral cirrophores. Segment 3 with small neuropodia with c. ten chaetae, with ventral cirri of similar size and shape as following segments. Aciculae in segments 2 and 3 unknown.

Dorsal cirri of median segments reniform, wider than long. Dorsal cirrophores of median and posterior segments with narrow extension on dorsal side of cirri; extension absent from anterior segments. Neuropodium with supra-acicular lobes longer than subacicular lobes, with c. 25 chaetae. Dorsal and ventral chaetae similar within single fascicle. Rostrum of chaetal shaft asymmetrical, with single main tooth on anterior side. Ventral cirri with rounded ends, c. 1.5 times as long as wide, slightly shorter than neuropodial lobes. Pygidial cirri cylindrical, with rounded ends, c. 1.5 times as long as wide. Pygidial papilla very short, knob-like.

Habitat

219–1837 m.

Distribution

Known from Ross Sea and eastern sector of Antarctica ( Monro, 1930), and Gulf de Ancud, Chile (Wesenberg- Lund, 1962).

Remarks

Paranaitis bowersi differs from other Paranaitis in the character combination dorsally elongated dorsal cirrophores of median and posterior segments, and proboscis with long distal part covered by six rows of tubercles, and with short proximal part with large lateral and ventral papillae.

PARANAITIS CAECA ( MOORE, 1903)

( FIGS 6–9 , 37 )

Eumida caeca Moore, 1903: 426–428 , pl. 23, fig. 1 (misspelled as Eumidia caeca ); Izuka, 1912: 203, pl. 21, fig. 5; Hartman, 1959: 152.

Paranaitis caeca: Eibye-Jacobsen, 1991: 129 .

Material examined

Holotype (USNM-15716), Sagami Bay, Japan, 74– 78 m; 2 specimens (ZIHU-2015), SW off Miura Peninsula, Sagami Bay , 35∞08.13¢N, 139∞36.21¢E, shell sand, 39 m, 12 May 1998, coll. F.P.; 1 specimen (ZIHU-1919), Otsuchi Bay , Iwate Honshu , Japan, 39∞20.7¢N, 141∞57.7¢E, sandy mud, 49 m, 7 May 1997, coll. T.K.

Description

Holotype complete ovigerous female, 73 mm long, 3.4 mm wide, for 188 segments; see Figure 9 for measurements of other specimens. Live animal white. Dorsum of segments 8–11 with brown pigmentation, forming transverse band. Dorsum of following segments with brown spot medially on each segment ( Fig. 6A ), and inner part of dorsal cirri with single large rounded brown spots; medial and lateral spots together forming three longitudinal lines. Colour well retained after preservation. Body long, dorso-ventrally flattened, anteriorly and posteriorly tapered. Prostomium rounded pentagonal, with shallow but distinct ligula. Paired antennae and palps stout, conical, laterally directed ( Fig. 6B, C ). Eyes absent. Nuchal papilla large, similar in shape to paired antenna, situated in shallow ligula. Nuchal organs rounded, large, situated laterally between prostomium and segment 1, visible dorsally and ventrally when everted ( Fig. 6B, C ). Proboscis not divided into proximal and distal parts, with lateral row of rounded papillae each side; dorsal surface entirely covered by pointed papillae, ventral surface by rounded small papillae ( Fig. 7 ). Terminal ring with c. 12 papillae. Paired large papillae present laterally inside ring.

Segments 1 and 2 fused. Cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3 stout, cylindrical, distally tapered ( Fig. 8A–C ). Cirri of segment 1 reaching c. segment 5. Dorsal cirri of segment 2 with acicula, reaching c. segment 9 ( Fig. 8B ). Ventral cirri of segment 2 reaching c. segment 6. Dorsal cirri of segment 3 with acicula, reaching c. segment 10 ( Fig. 8C ). Segment 2 with dorsal and ventral aciculae, and c. 4 chaetae arising from cirrophores of ventral cirri ( Fig. 8B ). Segment 3 with dorsal aciculae, small neuropodial lobes with ventral aciculae and c. ten chaetae, and ventral cirri.

Dorsal cirri of median segments kidney-shaped, wider than long ( Fig. 8F–I ). Dorsal cirrophores distally enlarged. Neuropodium with supra-acicular lobes longer than subacicular lobes, with 25–30 chaetae. Dorsal and ventral chaetae similar within single fascicle. Rostrum of chaetal shaft symmetrical, with single short main tooth both sides ( Fig. 37B ). Ventral cirri oval with rounded to weakly pointed ends, longer than neuropodia ( Fig. 8G,I ). Pygidial cirri cylindrical, with rounded ends, 2–3 times as long as wide ( Fig. 6D ). Pygidial papilla present.

Habitat

Sandy mud, 49 m. Paranaitis uschakovi and P. caeca , two poorly known species from Japan, are similarly in lacking eyes and in having white body with brown pigmentation. Eibye-Jacobsen (1991), based on an examination of the holotype of P. caeca and, presumably, the original description of P. uschakovi , considered the two species as distinct based on the following differences: (1) shape of prostomium, (2) length of dorsal cirri of segments 2 and 3 (those of segment 3 distinctly longer in P. uschakovi , of equal length in P. caeca ), (3) asymmetrical dorsal cirri in P. uschakovi (supposedly considered symmetrical in P. caeca ), and (4) length of ventral cirri (shorter than neuropodium in P. uschakovi , longer in P. caeca ). We examined the newly collected specimens of both species from Otsuchi Bay, as well as the holotypes of P. caeca and P. uschakovi , and concluded that most characters above are not suited to differentiate the two taxa. Instead, they may be separated by the following features: (1) shape of nuchal papilla (long and pointed in P. caeca ; short and rounded in P. uschakovi ), (2) position of nuchal organs (laterally in P. caeca ; ventro-laterally in P. uschakovi ), (3) shape of paired antennae, palps and anterior cirri (narrower paired antennae and palps, and thinner cirri of segments 1–3 in P. uschakovi ), (4) presence of proboscis papillae in P. caeca , (5) presence of ciliated furrows on the dorsal cirrophores of P. uschakovi , (6) presence of a dorsal longitudinal line in P. caeca , (7) morphology of the rostrum of chaetal shaft (symmetrical without main tooth in P. caeca ; asymmetrical with single main tooth in P. uschakovi ), and (8) different growth patterns ( Fig. 9 ).

Distribution

Known from Sagami Bay, Uraga Channel ( Izuka, 1912) and Otsuchi Bay, Japan.

Remarks

Paranaitis caeca differs from other Paranaitis in the character combination of dorsally papillated proboscis, absence of eyes, elongated and pointed nuchal papilla, symmetrical rostrum of chaetal shaft, and unique pigmentation pattern.

PARANAITIS GARDINERI PERKINS, 1984

( FIGS 10–12 )

Paranaitis gardineri Perkins, 1984: 563–565 , fig. 4.

Paranaitis polynoides: Gardiner, 1976: 110 , fig. 6m –p; Gathof, 1984: 19-21 to 19-23, figs 19-17 to 19-18. Not Anaitis polynoides Moore, 1909 .

Material examined

Holotype (USNM-52876), off Cape Lookout, North Carolina, USA; 2 paratypes (USNM-52877), Wrightsville Beach, North Carolina; 1 paratype (HZM-P- 17600), Hutchinson Island, Florida, USA; 1 paratype ( FSBC I 30424), Hutchinson Island, 27∞20.24¢N, 80∞13.04¢W, 10.9 m; 1 paratype ( FSBC I 30425), Hutchinson Island , 27∞21.23¢N, 80∞13.24¢W, 10 m; 1 paratype ( FSBC I 30426), Hutchinson Island , 27∞22.08¢N, 80∞13.46¢W, 10.6 m; 1 specimen (mounted for SEM, not kept), Hutchinson Island , 27∞21.6¢N, 80∞13.2¢W, 11 m, 4 April 1997, coll. F.P.; 6 specimens (USNM-45527), Tampa Bay , Florida; 1 specimen (USNM-56127), Gulf of Mexico , 29∞36¢N, 87∞48¢W, 37 m; 1 specimen (USNM-51022), Beaufort, North Carolina, 34∞04¢N, 75∞25¢W, 20 m; 1 specimen (USNM-59331), off Georgia, Gulf of Mexico , USA, 31∞01¢N, 80∞17¢W, 40 m; 1 specimen (USNM- 59332), off Georgia, 31∞01¢N, 80∞17¢W, 40 m; 1 specimen (USNM-59333), off Georgia, 30∞57¢N, 79∞58¢W, 183 m; 1 specimen (USNM-59334), off Georgia, 31∞03¢N, 80∞26¢W, 34 m; 1 specimen (USNM-75587), off Florida, Gulf of Mexico , 29∞34¢N, 80∞22¢W, 44 m; 1 specimen (USNM-59335), Mississippi Sound, Alabama, Gulf of Mexico , 30∞03.12¢N, 88∞14.24¢W, 21 m; 1 specimen (USNM-75589), Mississippi Sound, 29∞59.20¢N, 88∞18.49¢W, 28.5 m; 1 specimen (USNM- 108159), off South Carolina, 31∞44.06¢N, 80∞13.06¢W, 33 m.

Description

Holotype complete with regenerated posterior end, proboscis everted, 37.5 mm long (excluding proboscis), 2.7 mm wide, for 101 segments. Up to 89 mm most animals from Florida lacking colour pattern ( Perkins, 1984). Preserved specimens pale yellow with brown spots on dorsum and dorsal cirri. Eyes blackish. Body long and slender, anteriorly and posteriorly tapered. Prostomium anteriorly rounded, with distinct deep ligula ( Fig. 10A ). Paired antennae and palps conical, antero-laterally to laterally directed. Eyes large, rounded, with lenses, situated at posterior margin of prostomium. Short rounded nuchal papilla inserted posteriorly in ligula, often partly covered by segment 1. Nuchal organs retractile, rounded with horseshoe-shaped bands of cilia, ventro-laterally situated ( Fig. 10B ). Proximal part of proboscis lacking tubercles, with gradual transition to distal part with tubercles ( Fig. 11A ). Rounded chitinous papillae covering dorsal, lateral and ventral surfaces of both proximal and distal part ( Figs 11A,B ). Papillae of terminal ring poorly defined. Paired large papillae present laterally inside ring. Segments 1 and 2 fused. Cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3 cylindrical, long and tapered. Cirri of segment 1 reaching c. segment 7. Dorsal cirri of segment 2 reaching c. segment 9. Ventral cirri of segment 2 reaching c. segment 7. Dorsal cirri of segment 3 reaching c. segment 11. Segment 2 without neuropodial lobes and chaetae. Segment 3 with small neuropodial lobes with c. 7 chaetae and small ventral cirri. Aciculae in segments 2 and 3 unknown. Dorsal cirri of median segments oval, slightly longer than wide in small specimens ( Fig. 10C ); reniform, wider than long in large specimens. Dorsal cirrophores distinct, wide. Neuropodium with supra-acicular lobes longer than subacicular lobes, with c. 35 chaetae. Dorsal and ventral chaetae similar within single fascicle. Rostrum of chaetal shaft asymmetrical, with single large main tooth on anterior side ( Fig. 10E ). Ventral cirri with rounded ends, as long as or slightly shorter than neuropodial lobes ( Fig. 10D ). Pygidial cirri c. 7 times as long as wide, tapering to pointed ends ( Fig. 11C ). Pygidial papilla present ( Fig. 10F ).

long, 3.1 mm wide, for 184 segments (paratype, USNM-52877); see Figure 12 for measurements of other specimens. Live animals from North Carolina reported as having diffuse purple spots on dorsum, ventrum, and digitate and flattened dorsal cirri; Habitat

Sand mixed with gravel and shell fragments, muddy sand and coarse calcareous sand, intertidally to 11 m.

Distribution

Known only from south-east US Atlantic coast.

Remarks

Paranaitis gardineri differs from other Paranaitis in the character combination proboscis with gradual transition between proximal and distal parts, long pygidial cirri with pointed ends, and specific body pigmentation. Paranaitis misakiensis is similar in proboscis features, but differs in having oval dorsal cirri with narrow dorsal cirrophores, pygidial cirri with rounded ends, and different body pigmentation. Based on re-examination of Gathof’s (1984) specimens (USNM-56127), her records of P. polynoides from the US Atlantic coast are referred to P. gardineri .

Figures

Figure 6. Paranaitis caeca. A–C, specimen from Otsuchi Bay, Japan (ZIHU-1919). D, specimen from Sagami Bay, Japan (ZIHU-2015). A, entire animal, dorsal view. B, anterior end, dorsal view. C, same, ventral view. D, posterior end, dorsal view.

Figure 7. Paranaitis caeca, specimen from Japan (ZIHU- 1919). Dissected proboscis, ventral view. Dorsal median line is indicated by a curved line.

Figure 8. Paranaitis caeca, specimen from Japan (ZIHU-1919). A, cirri of segment 1, anterior view. B, parapodium of segment 2, anterior view. C, parapodium of segment 3, anterior view. D, parapodium of segment 4, anterior view. E, parapodium of segment 5, anterior view. F, parapodium of segment 64, anterior view. G, same, posterior view. H, parapodium of segment 106, anterior view. I, same, posterior view.

Figure 9. Paranaitis caeca and P. uschakovi, specimens from Japan. Relationships between A, number of segments and body length, B, number of segments and body width, and C, body length and body width. Circles represent P. caeca, and squares P. uschakovi.

Figure 10. Paranaitis gardineri, SEM micrograph of specimen from Florida, USA. A, anterior end, dorsal view. B, same, ventro-lateral view. C, median segments, dorsal view. D, same, ventro-lateral view. E, chaetae, dorsal view. F, pygidium, ventral view (tip of pygidial cirri probably damaged).

Figure 11. Paranaitis gardineri, holotype. A, anterior end, with partly everted proboscis, dorsal view. B, chitinous papillae from dorsal distal part of proboscis. C, posterior end, ventral view.

Figure 12. Paranaitis gardineri, specimens from USA. Relationships between A, number of segments and body length, B, number of segments and body width, and C, body length and body width.

Figure 37. Chaetae of species of Paranaitis. A, P. wahlbergi, specimen from Sweden, ZIHU-2014. B, P. caeca, specimen from Japan, ZIHU-1919. C, P. kosteriensis, specimen from Sweden, SMNH-22547, dorsal chaetae. D, P. kosteriensis, same specimen, ventral chaetae. E, P. misakiensis sp. nov., paratype, ZIHU-1381. F, P. polynoides, ZIHU-2016. G, P. pumila sp. nov., paratype, ZIHU-1379. H, P. speciosa, syntype USNM 380. I, P. speciosa, specimen from Japan, ZIHU-1921. J, P. uschakovi, specimen from Japan, ZIHU-1923.