Hesione paulayi, Salazar-Vallejo, 2018

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 286-289

Hesione paulayi n. sp.

( Figs 37 , 38 )

urn:lsid:zoobank.org:act:1ECD169E-717B-458F-8F82-B252A684074F

Hesione genetta – Fauvel 1919b: 370; 1923b: 15, 16; 1947b: 89, 90 (partim, Gambier Islands). — Horst 1924: 193 (partim, Indonesia). — Hartman 1954: 622 (partim, Marshall Islands).

Hesione pacifica – Treadwell 1906: 1149, fig. 4 (non McIntosh, 1885).

Hesione splendida – Bailey-Brock & Hartman 1987: 261, fig. 3.II.32 (Hawaii; non Savigny in Lamarck, 1818).

Hesione sp. TRANS. — Uchida 2011: 3-4, fig. 1.

TYPE MATERIAL. — Papua New Guinea. Holotype, UF 32 and two paratypes ( UF 5845 ), Milne Bay Province, Louisiade Archipelago, Misima Island, 1.6 km NW of Pt. Ebola, along North coast (-10.612, 152.539833; 10°36’43.2000”S, 152°32’23.3988”E), 31.V.1998, G. Paulay coll. [paratypes 30-33 mm long, 2.5 mm wide; slightly dehydrated, one laterally bent; both with a well-defined brownish band along chaetiger 2, 3 times wider than following ones, but no band in chaetiger 1, and feebly defined in chaetiger 3; present along chaetigers 4-10(11); pharynx partially exposed, dorsal papilla not seen; antennae digitate, longer than interocular distance; eyes brownish, anterior ones about twice as large as posterior ones; right parapodia removed from one paratype in chaetigers 2, 8, 14; longest tentacular cirri reaching chaetiger 5; median parapodia with dorsal cirri longer than body width, including parapodia; posterior end maculate; pygidium with anus projected, with 7 blunt anal papillae].

ADDITIONAL MATERIAL. — French Polynesia. Society Islands , Moorea Island. 1 specimen, UF 887 , mid-way between Sheraton and Gump station (-17.4801, -149.8351; 17°28’48.3600”S, 149°50’06.3600”W), lagoon, 2 - 4 m depth, 11.XI.2008, A. Anker, J. Moore, S. McKeon & V. Ivanenko coll. [38.5 mm long, 3 mm wide; slightly wider towards the posterior region; pigmentation includes transverse bands and circular spots, progressively less marked posteriorly; a wider, darker transverse band in chaetiger 2; body wall transparent; neuraciculae visible dorsally; parapodia with multiarticulated cirri; acicular lobe double, each capitae, upper one longer; neurochaetal blades bidentate, guard reaching subapical tooth; sometimes apical tooth with a shallow nuchal depression] .

Tuamotu Islands . 1 specimen, MCZ 46413 , RV Albatross, unnumb. Sta., Mekema (Makemo) Island (16°35’S, 143°40’W), 21.X.1899 [18.5 mm long, 4 mm wide).

Gambier Islands. 3 specimens, MNHN-IA-PNT 91l (formerly jar 70, in separate containers), Vaiatekeue , Gambier Group , 13.X.1903, L. G. Seurat coll. [25-30 mm long, 2.5-4.0 mm wide; pigmentation almost completely faded out, only a wide barely-defined brownish band on chaetiger 2 (“sublimé” in label), better defined in the other specimen; smaller specimen with body wall broken, exposing oocytes now adhered on back; oocytes about 100 µm] .

Philippines. 1 specimen, UF 586 , Negros Oriental Prov., Dumaguete, behind Silliman University Marine Lab and Dumaguete Airport (9.33592, 123.3097; 09°20’09.3120”N, 123°18’34.9200”E), patch reef, lagoon, methylated spirits, 3 - 4 m depth, 22.V.2006, K. Netchy & A. Kerr coll. [27 mm long, 3 mm wide, partially dehydrated; pigmentation pattern including a wide dorsal transverse dark bands on chaetiger 2, but no transverse bands on chaetigers 1 and 3; transverse bands and dark spots progressively thinner, paler posteriorly] .

Northern Marshall Islands. 1 specimen, LACM 10162 , Eniwetak Atoll , 17.XII.1946, F. C. Z. coll. [26 mm long, 2.5 mm wide; pinkish, with abundant salt particles adsorbed; eyes unpigmented; antennae as long as interocular distance; prostomium as long as wide, prostomial posterior margin completely exposed, deeply furrowed, reaching ¼ prostomial surface; dorsal cirri thin, delicate; acicular lobe double, upper tine digitate, lower tine shorter, blunt; neurochaetal blades with large subdistal tooth, guard approaching it; pygidium smooth, irregular because of adsorbed materials; anal tube projected, anal papillae not visible].

Mariana Islands. 1 specimen, UF 43 , Guam Island , Cocos Island, S side (13.5, 144.8; 13°30’00.0000”N, 144°48’00.0000”E), forereef, under rubble, 20 m depth, 2.XI.1999, L. Kirkendale coll. [37 mm long, 3 mm wide; body bent laterally, slightly distorted; pigmentation pattern with a thick brown transverse band on chaetiger 2, missing on chaetigers 1 and 3, thinner, paler on chaetigers 4-8; pharynx not exposed; antennae digitate, longer than interocular distance; eyes dark brown, fading out, anterior ones about twice as large as posterior ones] . — 1 specimen, UF 50 , Guam Island , Apra Harbor, Gab Gab Beach (13.5, 144.8; 13°30’00.0000”N, 144°48’00.0000”E), in rubble, 3-5 m depth, 9.XII.1997, L. Kirkendale coll. [26 mm long, 3.5 mm wide, stiff, bent dorsally; pigmentation pattern as thin transverse lines on chaetigers 2, 4-7, following ones without transverse bands, first band twice as wide as others, missing on chaetigers 1 and 3; pharynx partially exposed, dorsal papilla not seen; antennae longer than interocular distance; acicular lobes capitate]. — 1 specimen, UF 700 , Guam Island , Mangilao, Pago Bay (13.426695, 144.796052; 13°25’36.1020”N, 144°47’45.7872”E), fore reef, 0-1 m depth, 14.III.2008, F. Michonneau & S. Kim coll. [38 mm long, 3 mm wide, partially dehydrated, distorted, parapodia directed ventrally; one dorsal, wide, dark brown transverse band on chaetiger 2, no bands in chaetigers 1 and 3, and discontinuous bands in chaetigers 4-8, progressively thinner and less defined; pharynx everted, basal ring with small brown spots; acicular lobe double, slightly notched subdistally, upper tine slightly longer than lower one; chaetal blades bidentate, subdistal tooth thicker than distal one, guard approaching subdistal tooth]. — 1 specimen, UF 1674 , Guam Island , Guam, Tepungan Channel under road (13.4649, 144.6872; 13°27’53.6400”N, 144°41’13.9200”E), inflow channel, 0 - 2 m depth, 12.VI.2010, N. Evans, F. Michonneau , G. Paulay, A. Anker, T. Naruse & D. Uyeno coll. [42 mm long, 3.5 pmm wide, bent laterally, median right parapodia removed for molecular studies; one gonadal tip removed; pigmentation pattern fading off, a thick dark, transverse brown band on chaetiger 2, chaetigers 1 and 3 without dark bands, barely visible along chaetigers 4-6, following segments pale; eyes almost depigmented, anterior ones twice as large as posterior ones; antennae longer than interocular distance; acicular lobe double, contracted, blunt, upper tine larger, slightly capitate, lower one rounded; neurochaetal blades medium-sized or short, bidentate, subdistal tooth wider than distal one, guard reaching subdistal tooth] .

Indonesia. Banda Islands. 1 specimen, RMNH V427 , May, 1921, van der Velde coll. [33 mm long, 5.5 mm wide; slightly distorted, many chaetae broken; a thick brownish transverse band on chaeti- ger 2, no band on chaetigers 1 and 3, other segments with thinner, barely pigmented bands; antennae tapered, 4-5 times as long as wide; eyes colorless; acicular lobe double; neurochaetal blades broken] .

Australia. 1 specimen, AM 31859, Surgeons Reef, N off North West Solitary Island; 30°00’28.8”S, 153°16’12.94”E, coral rubble & coarse shelly sediment, 30.IV.2005, R. T. Springthorpe coll. [33 mm long, 3.7 mm wide, body wall broken, previously midventrally dissected along first 7 chaetigers; first band wider with irregular margins; neurochaetal blades bidentate, subdistal tooth as wide or wider than distal one; guard approaching subdistal tooth].

Coral Sea. 1 specimen, MNHN MUSORSTOM 10, Beffona Expedition, Sta. 10DE (21°24.3’S, 158°56.8’E), 52 m depth, 20.X.1985 [22 mm long, 2.5 mm wide; bent laterally, almost without pigmentation, only first band on chaetiger 2 barely visible; prostomium and most parapodial lobes invaginated; acicular lobe double, exposed in several chaetigers].

Hawaii. 2 specimens, USNM 5433 , RV Albatross, Sta. 3876, Auau Channel , Maui Island, Lahaina , 3 m depth, 14.IV.1902 [16-21 mm long, 2 mm wide; juveniles; body slightly macerated, larger specimen regurgitated sediment, both with pharynx partially everted; antennae medium-sized, digitate, visible after methyl-green staining; chaetal lobes invaginated; pigmentation lost].

ETYMOLOGY. — This species is named after Gustav Paulay, Curator of Malacology and Marine Invertebrates , Florida Museum of Natural History , University of Florida, Gainesville , in recognition of his efforts to sample and study tropical marine invertebrates all over the world, and because of his long-term sustained efforts to collect specimens of Hesione , including the type specimens. The name is a noun in genitive ( ICZN 1999 : art. 31.1.2).

DISTRIBUTION. — Widely distributed along the tropical Western Pacific, including Hawaii, in shallow water, mixed bottoms; localities for the Paumotu (Tuamotu) Archipelago were adjusted after the compilation by Young (1899).

DIAGNOSIS. — Hesione with prostomium laterally curved; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore twice as long as wide; larger acicula blackish; acicular lobe double, tines digitate, upper one twice longer than lower one; neurochaetal blades bidentate, 3-4 times as long as wide; subdistal tooth as large as distal one, with guards approaching subdistal tooth.

DESCRIPTION

Holotype, UF 32, complete, tapered posteriorly. Pigmentation pattern including brownish, dorsal transverse bands and irregular spots; transverse bands better defined along anterior chaetigers but none in chaetiger 1, barely defined, discontinuous in chaetiger 3 ( Fig. 37A ); chaetiger 2 with a wide band, better defined, straight, along its anterior margin, posterior margin irregular, 3-4 times longer than band in chaetiger 4; following chaetigers with progressively less defined bands. Pigmentation extended into lateral cushions; tentacular cirri, dorsal cirri and neuropodial lobes whitish in ethanol. Body straight, 29 mm long, 3 mm wide.

Prostomium slightly as wide as long, anterior margin truncate, lateral margins rounded, posterior margin with a shallow notch, 1/5 as long as prostomium ( Fig. 37B ). Antennae digitate, 4-5 times as long as wide, or longer than interocular distance. Eyes brownish, anterior ones twice as large as posterior ones.

Tentacular cirri thin, some broken, others twisted, longest ones reaching chaetiger 5. Lateral cushions low, divided into 2-3 sections.

Parapodia (dissected from paratypes) with chaetal lobes tapered, truncate ( Fig. 37C ); dorsal cirri with cirrophores about twice as long as wide, cirrostyle basally cylindrical, smooth, articulated throughout most of its length, longer than body width (including parapodia); ventral cirri irregulary contracted, few complete, reaching chaetal tips.

Neuraciculae blackish, two very thick, and one additional thinner, paler. Acicular lobe double, tapered, capitate, at least upper tine, lower tine thicker, tapered, size variable, up to twice as long as lower one ( Fig. 37C [inset]).

Neurochaetae about 20 per bundle, blades bidentate, 3-4 times as long as wide; blades aligned at a certain angle from handle, teeth of similar length, subdistal tooth usually wider, guard thick, approaching subdistal tooth ( Fig. 37D ).

Posterior region tapered into a blunt cone ( Fig. 37E ); pygidium rugose, anus with seven low, blunt triangular papillae.

Pharynx partially exposed, dorsal papilla not seen. Oocytes not seen.

Pigmentation

Preserved specimens with long-lasting distinct pigmentation pattern: first chaetiger pale or with scattered roundish spots. Second chaetiger with a distinct transverse, wide band. Chaetiger 3 with a subcontinuous thinner band, sometimes replaced by scattered roundish spots, or by irregular spots ( Fig. 38 A-C).

REMARKS

As indicated above, Hesione paulayi n. sp. belongs to the group with long-lasting pigmentation, including transverse brownish bands, together with H. genetta Grube, 1867 restricted, and H. mooreae n. sp. As indicated in the key below, H. genetta has its larger transverse band in chaetiger 1, whereas both H. paulayi n. sp. and H. mooreae n. sp. have them on chaetiger 2. These two latter species have three main differences; in H. paulayi n. sp. the upper acicular lobe is tapered, the posterior margin of its largest band is not well-defined, and the longest tentacular cirri reach chaetiger 6, whereas in H. mooreae n. sp. the upper acicular lobe is digitate, the posterior margin of the largest band is as well defined as its anterior margin, and its longest tentacular cirri reach chaetiger 8.

As indicated in the remarks for H. genetta Grube, 1867 there are at least three similar, long-lasting pigmentation patterns, both having a variable number of purple to brownish circular spots per segment, sometimes middorsally grouped into larger irregular bands. However, in H. paulayi n. sp. transverse bands are better defined, usually with a larger darker band over chaetiger 2, but no bands over chaetigers 1 and 3 (sometimes an irregular, discontinuous thin line can be present), whereas in H. genetta transverse bands are present on chaetigers 1 and 3, and sometimes an ill-defined band, or none at all on chaetiger 2. Further, in H. paulayi n. sp. the upper tines of acicular lobes are usually larger, digitate to capitate. These features are consistently different and specimens with these pigmentation patterns turned out separately in their COI-sequences.

Figures

FIG. 37. — Hesione paulayi n. sp.: A, holotype, UF 32, anterior region, dorsal view; B, same, anterior end, dorsal view; C, paratype, UF 5845, chaetiger 8, right parapodium anterior view (inset: acicular lobe); D, same, neurochaetal blades; E, holotype, posterior region, dorsal view. Scale bars: A, 1.5 mm; B, 0.7 mm; C, 0.2 mm; D, 20 µm; E, 1.3 mm.

FIG. 38. — Hesione paulayi n. sp., anterior region of three different specimens, arranged in a progressive reduction of the discontinuous band in chaetiger 3: A, paratype, Papua New Guinea, UF 5845; B, non-type specimen, Society Islands, Moorea, UF 887; C, non-type specimen, Eastern Australia, AMNH 31859. Scale bars: A, 1.1 mm; B, 0.8 mm; C, 1.2 mm.