Parasabella undetermined

Capa, María & Murray, Anna, 2015, Integrative taxonomy of Parasabella and Sabellomma (Sabellidae: Annelida) from Australia: description of new species, indication of cryptic diversity, and translocation of some species out of their natural distribution range, Zoological Journal of the Linnean Society 175 (4), pp. 764-811 : 791-796

PARASABELLA SP. CF. P. JAPONICA ( MOORE & BUSH, 1904) ( FIGS 4F , 5F, U, V, 14 , 15 )

Sabella japonica Moore & Bush, 1904: 157–159 , pl. XL, figures 1, 2, pl. XII, figures 39, 40. – Imajima & Hartman, 1964: 363.

Parasabella japonica – Tovar-Hernández & Harris, 2010: 15.

Australian material examined (see Appendix): Australia. Western Australia, Kimberley region (three) . Northern Territory. Darwin Harbour , (two, including one by SEM) ; Queensland: Heron Island (five); Lizard Island (one) . New South Wales: Burrewarra Point (five, including one by SEM); Jolong Reef (one) . Tasmania. Port Davey (one) ; South Australia. Kangaroo Island (one) .

Diagnosis: Radiolar eyes absent. Radioles supported by 6–8 rows of vacuolated cells near bases. Thoracic ventral shields separated from neuropodial tori by wide gap. Inferior thoracic notochaetae type B, hoods width 1.5 times width of shaft, as long as 9–10 times maximum width. Thoracic uncini with mediumlength handles, neck slightly longer than breast.

Description of Australian specimens: Largest specimen ( SAM TE 14511) 13 mm long excluding crown, crown 7 mm; eight thoracic and 41 abdominal chaetigers. Radiolar crown basal lobes as long as one thoracic chaetiger, with 12–14 pairs of radioles arranged in semicircles ( Fig. 14A–C, G–I ). Radioles supported basally by six to eight rows of vacuolated cells at bases ( Fig. 4F ). Radiolar tips wide, tapering, bare for approximately length of single pinnule. Radiolar flanges and eyes absent in large specimens. Smaller (juvenile) specimens (5– 8 mm long with 5–7 pairs of radioles, e.g. AM W.31101, AM W.46989) show wide flanges along radioles that end subdistally in a scoop-like formation ( Fig. 14E, F ). Dorsal lips with radiolar appendages as long as eight thoracic chaetigers ( SAM TE 14511), each with single pinnular appendage. Posterior peristomial ring collar up to base of radiolar crown, with lateral margins oblique, increasing in length ventrally, with ventral lappets as long as one thoracic segment, subtriangular ( Figs 14D, E , 15A ); with rounded dorsal margins. Peristomial eyes present subdermally. Anterodorsal fleshy swelling absent. Thoracic ventral shields almost square or slightly wider than long, separated from thoracic tori by wide gap. Collar chaetae elongate, narrowly hooded. Superior thoracic notochaetae elongate narrowly hooded ( Fig. 15D ); inferior thoracic notochaetae broadly hooded with slender and progressively tapering hoods (type B; Figs 5F, 15E ) 1.5 times the width of shaft, 9–10 times as long as its maximum width. Thoracic uncini with 8–10 rows of teeth over main fang, covering slightly over half length of main fang ( Fig. 15G ), welldeveloped breast, neck slightly longer than breast, and handle twice length of the distance between breast and main fang ( Fig. 5U). Thoracic neuropodial companion chaetae with subdistal end enlarged, conspicuous microtubercles forming hood resulting in dentate appearance, thin distal mucro compressed laterally ( Fig. 15H ). Abdominal neurochaetae narrowly hooded ( Fig. 15I ). Abdominal uncini with about seven rows of teeth over main fang covering half length of main fang ( Fig. 15J ), neck as long as breast, breast well developed, and short handle (<1 the length of the distance from main fang to breast). Pygidium a rim with ventral anus and several red eyespots present on both sides.

Colour pattern: Live specimens show a broad variation of pigments. Specimens examined have red, pink, yellow, and white bands and spots on radiolar crown, but in some, the dominant colour is red ( Fig. 14A, B ), whereas in others it is white ( Fig. 14C, D ); white and yellow spots scattered along the trunk, especially in thoracic segments ( Fig. 14A–D ). Preserved specimens with no pigmentation or only a few reddish spots on radiolar crown ( Fig. 14E, G–I ).

Reproductive features: Some specimens are gravid females with eggs in abdomen.

Genetic data: The maximum genetic divergence amongst the four ITS fragment sequences obtained from specimens collected in New South Wales and Queensland was 7.1%. The genetic distance to other species was 17.1–23.7%. The four specimens analysed are characterized by several one-nucleotide synapomorphies and a short and unique block, ACTTG, in the 172–176 nucleotide positions of the alignment .

Remarks: The specimens collected in Australia share diagnostic features with the original description of P. japonica from Suraga Bay ( Japan), such as ventral shields separated from tori by a wide gap, long and slender inferior thoracic chaetae (type B), thoracic uncini with long to medium-length handles ( Moore & Bush, 1904: plate XII, fig. 39), and a collar with conspicuous pointed ventral lappets. The specimens described from Japan are bigger (up to 33 mm in length) than Australian specimens, which are not longer than 15 mm. It was not possible to compare certain features between populations such as length of dorsal lips (almost as long as the thorax in Australian specimens) and number of cells basally supporting radioles (6–8 cells in the Australian specimens), as these were not specified in the original description of P. japonica and are impossible to confirm in the type material of this species because the only two types (deposited in Academy of Natural Sciences Philadelphia, and the Smithsonian Institution) have lost their crowns ( Loi, 1980).

Other species in the genus possessing thoracic ventral shields separated from neuropodial tori are Parasabella lacunosa , P. torulis , and Parasabella polarsterni . Of these P. torulis is distinguished from the others by the presence of broad and short inferior thoracic notochaetae (type A) as well as thoracic uncini with short handles ( Table 2), whereas the rest of the species have inferi- or thoracic notochaetae of type B and longer uncini handles. Parasabella lacunosa has radioles basally supported by about ten vacuolated cells whereas P. sp. cf. P. japonica and P. polarsterni have six to eight. These latter two species can be separated by uncinial morphology. Thoracic uncini of P. polarsterni have necks shorter than breasts and handles three times longer than the distance between breast and main fang, whereas in P. japonica the uncini are longer than wide, with long necks and breasts of similar length and handle lengths that are up to twice the distance from breast to main fang.

In small specimens with few radioles (e.g. AM W.31101, Fig. 14E, F ) these radioles appear to be widened into distal ‘scoops’, or along their longitudinal axes forming flanges, features that suggest a specialized juvenile function, perhaps to increase the surface area available for feeding.

Type locality: Suruga Bay , Japan, 115–137 m depth, sand and gravel .

Distribution: Japan, Australia (in both tropical and temperate waters; Fig. 1B ); and? New Zealand. Parasabella japonica was reported from New Zealand by Glasby et al. (2009) as Demonax japonicus , but this record was based on a single specimen (identified by P. Knight- Jones) that is now misplaced. Further extensive sam- pling in New Zealand has failed to provide additional specimens of P. japonica since that record (G. Read, pers. comm.) and so its presence in New Zealand is herein regarded as dubious.

Ecological notes: Specimens from Australia have been collected from 1–30 m depth, in dead coral rubble, associated with sponges, bryozoa, and algae, and also in coarse sand.

PARASABELLA SP. CF. P. RUGOSA ( MOORE, 1904)

( FIGS 4G , 5G, W, X, 16 , 17 )

Distylia rugosa Moore, 1904: 499–501 , pl. 38, figures 8– 41; 1909: 289. – Loi, 1980: 143, 144.

Demonax medius – Berkeley & Berkeley, 1952: 115.

Distylidia rugosa – Hartman, 1961: 129; 1969: 667, in part. – Banse, 1979: 870.

Sabella (Demonax) media – Banse, 1979: 878–880. – Hobson & Banse, 1981: 107, in part.

Demonax rugosus – Perkins, 1984: 304–307, figures 9, 10.

Parasabella rugosa – Tovar-Hernández & Harris, 2010: 15.

Material examined (see Appendix for details): Australia. Victoria: Port Phillip Bay (three).

Diagnosis: Radiolar eyes absent. Radiolar lobes as two semicircles curling midventrally, with radioles arranged in two or more rows. Radioles with over 20 rows of vacuolated cells supporting radioles near bases. Inferior thoracic notochaetae elongate, slender (type B), hoods up to 1.5 times as wide as shafts and as long as ten to 12 times maximum width. Thoracic uncini with long handles, neck half length of breast.

Description of Australian specimens: Largest specimen about 55 mm long (excluding crown), crown 25 mm long, 8 mm wide, with eight thoracic and more than 100 abdominal segments. Radiolar crown basal lobes as long as one thoracic chaetiger, over 40 pairs of radioles arranged in alternating double rows forming semicircles in each branchial lobe, curling inwards ventrally. Radioles quadrangular in cross-section, each support- ed basally by more than 20 vacuolated cells in radiolar cross-section near bases ( Fig. 4G ). Radiolar tips thin and even width, bare for approximately length of one pinnule or 1.5 times length of a thoracic segment. Radiolar flanges and eyes absent. Dorsal lips as long as 5–8 thoracic segments, with one to three pairs of pinnular appendages. Posterior peristomial ring collar of even height all around or slightly longer dorsally, covering junction of crown and peristomium; with lateral notches, rounded ventral lappets, and dorsal margins rounded to flap-like ( Figs 16A–C , 17A ). Peristomial eyes not seen. Anterodorsal fleshy swelling absent. Thoracic ventral shields almost three times longer than wide, in contact with thoracic neuropodial tori ( Fig. 16A ). First ventral shield 1.5 times longer than following and with m-shaped anterior margin ( Fig. 16A ). Collar chaetae elongate, narrowly hooded. Superior thoracic notochaetae elongate, narrowly hooded ( Fig. 17B ); inferior thoracic notochaetae type B, slender, with hoods up to 1.5 times as wide as shafts (type B) and 10–12 times maximum width ( Figs 5G, 17B, C ). Thoracic uncini with 8–10 rows of teeth over main fang, covering half length of main fang ( Fig. 17D ), with a narrow breast, neck as long as breast, and long handle, over twice length of the distance between breast and main fang ( Fig. 5W). Thoracic neuropodial companion chaetae with subdistal end enlarged, conspicuous microtubercles forming hood resulting in dentate appearance, thin distal mucro, at right angle to shaft, compressed laterally ( Fig. 17E, F ). Abdomen with rugose epithelium in posterior chaetigers. Abdominal neurochaetae narrowly hooded ( Fig. 17G, I ). Abdominal uncini with minute rows of teeth over main fang covering half length of main fang ( Fig. 17H ), neck as long as breast, breast well developed, and short handle (shorter than the length of the distance between main fang and breast; Fig. 5X). Pygidium a rim with a ventral anus and several red eyespots present on both sides. Tube thick, chitinous, translucent, with sand grains, shell grit, and other tubes embedded into the tube mucous matrix.

Colour pattern: Preserved specimens with radiolar crown with faded transverse brown bands and pigmented pinnule bases, no spots along radiolar axes ( Fig. 16B, C ). Body unpigmented ( Fig. 16A–D ).

Genetic data: No specimens available for DNA sequencing.

Remarks: Parasabella rugosa , originally described from California and reported along the American Pacific coast up to British Columbia ( Perkins, 1984), is distinguished from other congeners by the presence of radiolar crowns with radiolar lobes partially spiralled, radioles arranged in double rows in large specimens, and slender inferior thoracic chaetae ( Perkins, 1984). The specimens collected in Port Phillip Bay, Australia, share all these features with specimens from the eastern Pacific coast, but also share the presence of a large number of rows of vacuolated cells supporting the radioles (20 or more at the base), long dorsal lips (as long as five to eight thoracic segments), the extremely slender form of the inferior thoracic chaetae, long-handled thoracic uncini, and rugose posterior abdomen (Moore, 1904; Perkins, 1984). Besides the barriers and distance separating theAustralian specimens from other eastern Pacific populations, the only feature that distinguishes these specimens is the length of the posterior peristomial ring collar, longer in the herein-described material than reported in the paratypes ( Perkins, 1984). This feature is probably not enough to consider these as a separate species. As only three specimens of this large Parasabella have been found in Australia, near an international port, translocation of the Australian population could explain the present distribution range of this species. Nevertheless, further investigations to identify any differences between these widely geographically separated populations should be performed when ethanolfixed specimens become available for examination and analysis.

Type locality: California, USA .

Distribution: East coast of North America ( USA and Canada); Port Phillip Bay, Australia ( Fig. 1B ).

Ecological notes: Species reported from 20–72 m ( Perkins, 1984). In Australia, it has been collected from fine shelly sand at 6 m depth.

Figures

Figure 1. Maps with collecting sites in Australia. A, Parasabella aberrans spp. complex, Parasabella sp. cf. Parasabella aulaconota, Parasabella bioculata sp. nov. B, Parasabella crassichaetae sp. nov. complex, Parasabella sp. cf. Parasabella japonica, Parasabella sp. cf. Parasabella rugosa, Sabellomma cupoculata sp. nov.

Figure 4. Cross-sections of radioles near the base showing the supporting cartilaginous vacuolated cells in the rachis (with grey nuclei), surrounded by an extracellular cartilaginous sheath (white) and covered by columnar epithelium (grey). Upper side of drawings are the outer margin of radioles; on the bottom incomplete pinnules are sketched with a blood vessel (black) in between. A, Parasabella aberrans spp. complex. B, Parasabella sp. cf. Parasabella aulaconota. C, Parasabella fullo. D, Parasabella bioculata sp. nov. E, Parasabella crassichaetae sp. nov. complex. F, Parasabella sp. cf. Parasabella japonica. G, Parasabella sp. cf. Parasabella rugosa. H, Sabellomma cupoculata sp. nov. A, AM W.36947; B, AMW.47009; C, ZMB 5731; D, AM W.46840; E, AM W.47181; F, AM W.36450; G, AM W.36431; H, AM W.47189.

Figure 14. Parasabella sp. cf. Parasabella japonica, colour micrographs. A–D, live specimens. A, anterior end, lateral view. B, radiolar crown and anterior thoracic chaetigers, lateral view. C, same, frontal view. D, colour pattern on lateral radioles. E–I, preserved specimens. E, distal end of radioles with well-developed radiolar flanges forming a ‘scoop’. F, scanning electron micrograph, radiolar crown, showing ‘flanged’ distal radioles. G, complete specimen, lateral view. H, posterior peristomial ring collar with enlarged ventral lappets, lateral view. I, same, dorsolateral view. A, B, AM W.37062; C, D, AM W.36451; E, F, AM W.31101; G–I, AM W.36451.

Figure 15. Parasabella sp. cf. Parasabella japonica, scanning electron microscope photographs. A, anterior thoracic chaetigers and base of radiolar crown, ventral view, showing ventral shields separated from neuropodial tori, and ventral lappets. B, anterior chaetigers, lateral view. C, same, dorsal view. D, midthoracic parapodium, elongate, narrowly hooded superi- or chaetae and broadly hooded type B chaetae in inferior group. E, detail of inferior, broadly hooded type B chaeta. F, thoracic uncini and companion chaetae. G, thoracic uncini, detail. H, companion chaetae showing the laterally compressed hood. I, midabdominal narrowly hooded neurochaetae. J, abdominal uncini. A–J, AM W.36450.

Figure 16. Parasabella sp. cf. Parasabella rugosa, colour micrographs of preserved specimens. A, anterior thoracic chaetigers, ventral view, showing posterior peristomial ring collar, and ventral shields in contact with neuropodial tori. B, complete thorax, lateral view. C, same, dorsal view. D, posterior abdominal chaetigers and pygidium, ventral view. A, NMV F.108844; B–D, AM W.36431.

Figure 17. Parasabella sp. cf. Parasabella rugosa, scanning electron microscope photographs. A, anterior thoracic chaetigers and base of radiolar crown, dorsal view, showing large collar dorsal margins. B, midthoracic parapodium with elongate, narrowly hooded (arrow) superior chaetae and broadly hooded (type B) in inferior group. C, detail of inferior thoracic broadly hooded chaetae of type B. D, thoracic uncini. E, companion chaetae, lateral view. F, companion chaetae, frontal view. G, midabdominal neurochaetae narrowly hooded. H, abdominal uncini. I, posterior abdominal chaetigers and (damaged) pygidium. A–I, AM W.36431.