Hesione fitzhughi, Salazar-Vallejo, 2018

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 249-251

Hesione fitzhughi n. sp.

( Figs 13 , 14 )

urn:lsid:zoobank.org:act:65EBF0A0-4CF8-40FD-97D2-D15EFB96CD3F

Hesione intertexta – Monro 1926: 311, 312 (partim, non Grube, 1878).

TYPE MATERIAL. — Australia. Holotype, LACM 10152 , and paratype, LACM 10153 , Brampton Island, off Mackay , Queensland, under rocks and coral boulders, 16-28.I.1949, B. Dew coll. (paratype partially dehydrated, pharynx exposed, most cirri lost; body 23 mm long, 2.5 mm wide).

ADDITIONAL MATERIAL. — Australia. 1 specimen, AM 4406 , Little Upolo Cay, 38 km NNE off Cairns, Queensland, under coral rocks, VII.1970, P. H. Coleman & I. Loch coll., [34 mm long, 5 mm wide; splendid specimen, slightly bent laterally, integument microtuberculated, anterior eyes as long as wide; pigmentation pattern barely visible along a few anterior chaetigers, longitudinal pale brown thin bands, interrupted serially in each parapodial region, leaving middorsal large, paler areas; antennae blunt, digitate to medially wider, 3-4 times as long as wide; right parapodium of chaetiger 8 removed for observation (kept in vial); neuraciculae black, tapered; acicular lobe single, basally swollen with a shallow notch, giving the impression of a round basal tine; about 25 neurochaetae per bunde, blades bidentate, subdistal tooth smaller, guard approaching distal tooth). — 1 specimen, AM E4642, Tasmania, off Babel Island, Bass Strait (39°56’S, 148°19’E), 146 m, FIS Endeavour , 1909-1914 coll. [45 mm long, 5 mm wide; complete, body ends distorted by compression into small container; integument smooth, lateral cushions with longitudinal ridges; right parapodium of chaetiger 2 removed for observation (kept in vial), others previously removed; antennae collapsed; eyes brownish, anterior eyes slightly larger than posterior ones; acicular lobe single, tapered, blunt; neurochaetal blades bidentate, subdistal tooth smaller, directed laterally, guards broken in a single blade approaching distal tooth, others approaching subdistal tooth]. — 1 specimen, AM W.5494, Hall Bank, Fremantle, Western Australia, under rocks, 13 m depth, 25.IV.1972, N. Coleman coll. [31 mm long, 4.5 mm wide; bent laterally, pharynx exposed; antennae digitate, as long as anterior eye diameter, eyes brownish, anterior eyes slightly larger than posterior ones; acicular lobe single, mostly blunt, sometimes tapered]. — 3 specimens, BMNH 1931.7.1.18/20, Great Barrier Reef Expedition, Low Isles, Queensland, no further data [the paper indicates four specimens, but there are only three in vial; 39-53 mm long, 5-6 mm wide; one sigmoid with several parapodia previously removed, two others straight; integument tuberculated; anterior eyes as long as wide; left parapodia of chaetiger 8 (sigmoid, without dorsal cirrus), and of chaetiger 10 (largest, with dorsal cirrus), removed for observation (kept in vial); acicular lobe single, basally swollen, blunt in two smaller specimens; largest specimen with acicular lobe tips bifid in several chaetigers of posterior region; neurochaetal blades bidentate, subdistal tooth smaller, guards most broken, a few entire approach subdistal tooth]. — 2 specimens, UF 55, Christmas Island (10°29’S, 105°38’E, South of Java), N Coast, 4 km E of Boat Cave , just outside Thundercliff Cave , dead coral rubble field, under large limestone rocks and rubble, 10 m depth, 21.XI.1999, L. Kirkendale coll. [35-48 mm long, 5.5-6.0 mm wide; colorless; antennae minute, difficult to see; eyes brownish, anterior ones slightly larger than posterior ones, largest specimen with anterior right eye divided into two complete, smaller eyes; longest tentacular cirri reach chaetiger 4; median chaetigers with dorsal cirri as long as body width (without parapodia); acicular lobes single, tapered; smaller specimen with neurochaetal blades bidentate, subdistal tooth smaller, guard reaching distal tooth].

Indonesia. 1 specimen, MNHN-IA-PNT92 (formerly jar 890), Gorong Islands, Moluccas, in corals, 26.I.1975, Th. Monod coll. [32 mm long, 5 mm wide; partially dehydrated; anterior eyes as long as wide, right one with inner area colorless, reniform; posterior eyes round; integument smooth; acicular lobe single, blunt; neurochaetal blades bidentate, subdistal tooth smaller, guards approaching distal tooth] . — 1 specimen, UF150 , Bay of Tomini, Pulau Pondang (0.45, 124.481277; 00°27’00.0000”N, 124°28’52.5972”E), Sulawesi, un- der rocks, 5-8 m depth, 18.IX.1999, G. Paulay coll. [30 mm long, 3.5 mm wide; bent ventrally; antennae minute; eyes of similar size, anterior ones blackish, posterior ones brownish, right posterior eyes duplicated, supernumerary one smaller; acicular lobe single, long, tapered; blades bidentate, subdistal tooth minute, guard approaching distal tooth].

Torres Strait. 2 specimens, BMNH 1926.4.30.90, RV Alert Expedition, Thursday Island, Torres Strait, 8-13 m depth, no further data [both complete, one pale, slightly macerated, the other grayish, stiff; anterior eyes as long as wide, slightly larger than posterior ones; integument tuberculated, lateral cushions smooth; body 35-38 mm long, 5-6 mm wide; acicular lobe single]. — 1 specimen, BMNH 1926.4.30.137, RV Alert Expedition, Holothuria Bank , Torres Strait [see Monro 1926] [complete, bent ventrally, right parapodia of chaetigers 7 and 8, and left one from chaetiger 10 previously removed; colorless, integument tuberculated, lateral cushions with longitudinal ridges; 40 mm long, 5 mm wide; left antenna twice as long as wide; anterior eyes as long as wide, twice larger than posterior ones; acicular lobe single, digitate; pharynx exposed, dorsal papilla blunt, twice as long as wide].

New Caledonia. 1 specimen, AM 7439 , found in aquarium, Noumea, VII.1975, E. Pope coll. [complete, bent laterally, tapered posteriorly; no pigmentation pattern but with a reddish hue; integument tuberculated. Body 45 mm long, 5 mm wide; left parapodia of chaetigers 1 and 10 previously removed, left parapodium of chaetiger 12 removed for observation (kept in vial); oocytes about 100 µm in diameter.] . — 1 specimen, MNHN-IA-PNT93 (formerly jar 402), Mrs Pruvot , no further data [24 mm long, 3 mm wide (rigth parapodium of chaetiger 8 removed for observation, kept in vial); antennae digitate, 3 times as long as wide; anterior eyes as long as wide, larger than posterior ones; integument rugose, microtubercles not forming longitudinal lines; acicular lobe single, tapered; neurochaetae about 20 per bundle; blades bidentate, subdistal tooth smaller, guard approaching distal tooth].

ETYMOLOGY. — This species is named after Kirk Fitzhugh, Curator of Polychaeta in the Los Angeles Museum of Natural History , Los Angeles, in recognition of his many publications on sabellid and terebellid taxonomy, as well as in philosophy of systematics, and because of his unreserved support to our research requests. The name is a noun in genitive ( ICZN 1999 : art. 31.1.2).

DISTRIBUTION. — Indonesia to New Caledonia, including Australia, under coral rocks in 0-13 m depth.

DIAGNOSIS. — Hesione with prostomium laterally curved; anterior eyes as long as wide; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore twice as long as wide; larger acicula blackish; acicular lobe single, tapered; neurochaetal blades bidentate, 3-5 times as long as wide; subdistal tooth smaller than distal one, with guards approaching distal tooth.

DESCRIPTION

Holotype, LACM 10152, complete, without pigmentation pattern in ethanol (more recently collected specimens with a reddish hue), slightly dehydrated ( Fig. 13A ); some tentacular or dorsal cirri broken or lost; left parapodium of chaetiger 10 removed for observation (kept in vial). Body slightly distorted, partially dehydrated, becoming slightly wider posteriorly, ventrally bent, 35 mm long, 5 mm wide.

Prostomium as long as wide, anterior margin projected anteriorly, lateral margins rounded, posterior margin deeply cleft, about as long as ¼ prostomial length, reaching slightly behind posterior eyes, without longitudinal depression ( Fig. 13B ). Antennae minute, directed laterally, fusiform, blunt, twice as long as wide, 4/5 as long as interocular distance. Eyes brownish, anterior eyes as long as wide, larger than posterior rounded ones.

Tentacular cirri long, some twisted, tips lost, longest ones reach chaetiger 4. Lateral cushions low, most entire, some separated into two sections.

Parapodia with chaetal lobes as long as wide, truncate; dorsal cirri with cirrophores 2-3 times as long as wide; cirrostyle basally cylindrical, annulated, multiarticulated medially and distally, as long as body width ( Figs 13C , 14C ). Ventral cirri smooth, surpassing chaetal lobe.

Neuraciculae blackish, two, one thinner (smaller specimen with acicula less pigmented). Acicular lobe single, tapered ( Figs 13C [inset]; 14C [inset]).

Neurochaetae about 20 per bundle, blades bidentate, blades at a certain angle from handle, 3-5 times as long as wide, decreasing in size ventrally, each with smaller subdistal teeth, a few blades with an additional, intermediate tooth ( Fig. 13D [insets]), guard approaching distal tooth, eroded in other specimens ( Fig. 14D ).

Posterior region tapered into a blunt cone ( Figs 13E , 14E ); pygidium granulate, anus with four petaloid papillae.

Pharynx exposed in paratype, margin smooth, slightly eroded; dorsal papillae rounded, as long as wide. Oocytes not seen (in a non-type specimen, AM 7439, 100 µm in diameter).

Pigmentation

A recently collected non-type specimen (AM W.7439) shows a reddish hue but not a definite pigmentation pattern. This reddish pigmentation is visible in the anterior ( Fig. 14A ), and posterior regions ( Fig. 14E ), slightly less evident in the prostomium ( Fig. 14B ), and especially in the neurochaetal lobe ( Fig. 14C ).

REMARKS

Hesione fitzhughi n. sp. can be confused with H. splendida Savigny in Lamarck, 1818 because of its shiny integument. However, H. splendida has a smooth integument, whereas H. fitzhughi n. sp. has it tuberculated. A tuberculate integument is also present in H. intertexta Grube, 1878 , as restricted above, but in H. intertexta lateral cushions are either smooth or with longitudinal ridges, whereas in H. fitzhughi n. sp. lateral cushions are tuberculated.

There are some photos available in internet depicting a reddish Hesione from the Western tropical Pacific, showing two pigmentation patterns: either with well-defined, discontinuous rectangular white areas, or with ill-defined, subcontinuous white areas. Matching this newly described species with either pigmentation pattern, or defining if there is more than a single species, requires the study of freshly collected specimens, and at least some COI-barcoding analysis. So far, H. fitzhughi n. sp. can be separated from other species in the intertexta group by having anterior eyes as long as wide and by its tuberculate integument, and in those specimens collected 40 years ago, there is a reddish hue along body.

Figures

FIG. 13. — Hesione fitzhughi n. sp.: A, holotype, LACM 10152, anterior region, dorsal view; B, same, prostomium, dorsal view; C, same, chaetiger 10, left para- podium, anterior view (inset: acicular lobe); D, paratype, LACM 10153, chaetiger 10, left parapodium, anterior view, neurochaetae (insets: blades and their tips); E, holotype, posterior region, dorsal view. Scale bars: A, 0.9 mm; B, 0.3 mm; C, 0.2 mm; D, 230 µm; E, 2.3 mm.

FIG. 14. — Hesione fitzhughi n. sp., non-type specimen, AM W.7439: A, anterior region, dorsal view; B, prostomium dorsal view (arrow points to right antenna); C, chaetiger 12, left parapodium, anterior view, dorsal cirrostyle broken (inset: acicular lobe); D, same, neurochaetal tips showing tip erosion; E, posterior region, dorsal view. Scale bars: A, 1.1 mm; B, 0.3 mm; C, 1 mm; D, 40 µm; E, 2.8 mm.