Hesione intertexta Grube, 1878

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 265-270

Hesione intertexta Grube, 1878 , restricted

( Figs 22-25 )

Hesione intertexta Grube, 1878: 102 , 103, pl. 6, fig. 5. — Malaquin & Dehorne 1907: 336. — Ehlers 1920: 26. — Horst 1924: 192, 193. — Monro 1926: 311, 312; 1931: 9, 10. — Fauvel 1947b: 31, fig. 26B. — Wu et al. 1975: 76, pl. 2, figs 9, 10. — Uchida 2010: 5, fig. 3. — Lee & Ong 2015: 203, 204, figs 3, 4.

Hesione pantherina – Fauvel 1930: 511; 1947a: 30, 31, fig. 27A4, (non Risso, 1826).

Hesione pantherina var. splendida – Augener 1933b: 181, 182, fig. 1A-C (non Risso, 1826 nec Savigny in Lamarck, 1818).

Hesione splendida – Gibbs 1971: 139 (non Savigny in Lamarck, 1818).

TYPE MATERIAL. — Western Pacific. Philippines. Holotype, MNHW 293 , Zamboanga, Semper coll.

ADDITIONAL MATERIAL. — Palau. 1 specimen, ZMB 3813 , Babeldaob , Semper coll., no further data [23 mm long, 4 mm wide; complete, one parapodium previously removed and placed in permanent slide; body dried-out almost completely, anterior end features collapsed; parapodia dehydrated; acicular lobe single, shape variable, short, blunt digitate to thinner, tapered; the permanent slide has the acicular lobe bent over itself and the tip of ventral cirri is partially covering it; few neurochaetae with blades, blades bidentate, guard approaching subdistal tooth, probably eroded].

Japan. 1 specimen, UF 1772 , Okinawa Prefecture, Okinawa Island, Okinawa, White Beach , campground (26.292824, 127.917392; 26°17’34.1664”N, 127°55’02.6112”E), shallow, very silty bay, 0 -4 m depth, 18.VII.2010, N. Evans, F. Michonneau, G. Paulay & J. Thomas coll. (used for redescription).

Indonesia. 1 specimen, RMNH 431.1, Lesser Sunda Islands, RV Siboga Exped. Stat. 33 (Bay of Pidjot, Lombok ), 22 m depth, trawl, muddy bottom, coral and coral sand, 24-26.III.1899 [36 mm long, 3 mm wide; colorless, bent laterally, posterior end bent dorsally; integument granulose, lateral cushions longitudinally ridged; pharynx partially everted, dorsal papilla as wide as long, surface irregular; anterior eyes twice as large as posterior ones; acicular lobe single] . — 1 specimen, RMNH 431.2, Sulawesi, RV Siboga Exped. Stat. 115, Kwandang Bay, E side of Pajunga Island , reef-exploration, 9-11. VII.1899 [42 mm long, 5 mm wide; colorless, integument granulose; anterior eyes twice as large as posterior ones; antennae minute 3-4 times as long as wide; longest tentacular cirri reaches chaetiger 5; dorsal cirri longer than body width, including parapodia; acicular lobe double, upper tine blunt, digitae, 3-5 times longer than lower tine, rounded to digitate] . — 1 specimen, RMNH 1278, Maluku, RV Siboga Exped. Stat. 144, anchorage N of Salomakiëe (Damar) Isl. , reef exploration, coral, 7-9.VIII.1899 [28 mm long, 5 mm wide; macerated, fusiform, integument granulose, retaining a lateral blackish spot on intersection of lateral cushions; right parapodium from chaetiger 7 removed for observation (kept in vial); acicular lobe double, lower tine about 2/5 as long as upper tine; neurochaetal blade bidentate, guard approaching distal tooth] . — 1 specimen, RMNH 1279, East Timor, South coast, at anchorage, RV Siboga Exped. Stat. 285 (08°39.1’S, 127°04.4’E), 34 m depth, dredge, muddy bottom and coral, 18.I.1900 [29 mm long, 3.5 mm wide; pharynx exposed; integument granulose, especially in posterior region, lateral cushions with roughly parallel longitudinal ridges; neuraciculae blackish, paler in anterior chaetigers; acicular lobe single; neurochaetal blades bidentate, teeth laterally directed, guards mostly eroded, approaching distal tooth] . — 1 specimen, RMNH 1280, Jakarta (Batavia) Bay , Sluiter coll., no further data [50 mm long, 7 mm wide; slightly macerated, integument granulose; most chaetal blades lost, remaining ones severely eroded; acicular lobe double, lower tine very variable, rounded to digitate, 1/5-1/3 as long as upper tine] . — 1 specimen, RMNH 1962, Siboga Expedition , Kalimantan, Borneo Bank , 5 miles NNE from stat. 79, RV Siboga Exped. Stat. 79b (02°38.5’S, 117°46’E), 54 m depth, trawl, coral sand, 12.VI.1899 [17 mm long, 3 mm wide; bent dorsally, pharynx exposed; body colorless, acicular lobe single, blunt; neurochaetal blades longer and medium-sized, bidentate, guard approaching distal tooth] . — 1 specimen, ZMH-P PE 312, Ambon Island (03°42’S, 128°10’E), 1887, no further data [49 mm long, 5 mm wide; colorless, integument granulose, lateral cushions with longitudinal ridges; antennae digitate, 2-3 times as long as wide; eyes colorless, anterior lenses slightly larger than posterior ones; acicular lobe single, tapered; most neurochaetal blades lost] .

Vanuatu. 1 specimen, UF 435 , Sanma Province, Rotua Island off Aore Island (-15.612222, 167.1775; 15°36’43.9992”S, 167°10’39.0000”E), sea grass and soft coral beds, 0 -2 m depth, 15.I.2005, C. Meyer coll. [beheaded; 34 mm long, 4 mm wide; some anterior segments with small, lateral, triangular dark spots ahead of chaetal lobes; acicular lobes single, long, tapered or blunt; neurochaetal blades bidentate, guard approaching distal tooth].

New Caledonia. 1 specimen, MNHN-IA-PNT91d (formerly jar 70a), Collection François , 1894 [29 mm long, 3.5 mm wide; prostomium damaged; integument with small tubercles dorsally, especially in median and posterior regions; parapodial lobes projected, with single acicular lobes] . — 1 specimen, MNHN-IA-PNT91e (formerly jar 70b), Collection François , no further data [40 mm long, 8 mm wide; macerated, bent laterally, parapodial lobes mostly invaginated, some show single acicular lobes] . — 1 specimen, MNHN-IA-PNT 91f (formerly jar 70c), 1880, no further data, M. Reveillere coll. [distorted, dried out, some exposed parapodia with single acicular lobes; neuraciculae tapered] . — 2 specimens, MNHNIA-PNT 91g (formerly jar 70d, separate containers), Mrs Pruvot , no further data [24-33 mm long, 3-4 mm wide; without pigmentation, bent ventrally; pharynx fully everted; acicular lobes single] . — 4 specimens, MNHNIA-PNT91h (formerly jar 70e), 41, Mrs Pruvot , no further data [dried out, too brittle as to measure them; some parapodia exposing single, tapered acicular lobes] . — 1 specimen, MNHN- IA-PNT96 (formerly jar Musorstom 645), Lagoon Est, Sta. 645 (21°50.3’S, 166°39.5’E), 51 m depth, 7.VIII.1986, B. Richer coll. [18 mm long, 2.5 mm wide; colorless; integument smooth; acicular lobe single; neurochaetal blades bidentate, subdistal tooth smaller than distal one] .

Marquesas Islands. 1 specimen, MNHN-IA-PNT97 (formerly jar Musorstom 1264), Ua Pou Island , Sta. 1264 CP (09°21.2’S, 140°07.7’W), 53-57 m depth, 3.IX.1997 [80 mm long, 10 mm wide; splendid, giant, without pigmentation; right parapodium from chaetiger 8 removed (kept in same container); antennae minute, twice as long as wide; anterior eyes twice larger than posterior ones; acicular lobes single, tapered; neurochaetal blades about 30 per bundle, most with guards and subdistal teeth eroded; subdistal tooth smaller, guard basally denticulated, approaching distal tooth; oocytes oval, centrally depressed, about 100 µm in diameter] .

Papua New Guinea. 1 specimen, UF 3974 , Madang Province, Sair Island (-5.18395, 145.802183; 05°11’02.2200”S, 145°48’07.8588”E), fringing reef inside lagoon, 8.XI.2012, J. Moore coll. [40 mm long, 5 mm wide; slightly macerated, with longitudinal, brownish irregular lines along first 6 chaetigers, chaetigers 6-10 with triangular brownish spots before chaetal lobes; antennae minute, digitate, shorter than interocular distance; anterior eyes twice as large as posterior ones; posterior prostomial margin notched, extended almost to the level of posterior eyes; acicular lobe single, variable contracted or eroded; neurochaetal blades bidentate, teeth lateral (only one with distally directed teeth in chaetiger 2), guard reaching distal tooth] .

Solomon Islands. 1 specimen, BMNH 1970.316, Royal Society Expedition to the Solomon Islands, 1965, Haniara, below Hotel Mendana, Acropora rubble, 6.VII.1965, MTL coll. [30 mm long, 5 mm wide; slightly bent laterally; antennae 2-3 times as long as wide; with some pigmented longitudinal lines remaining, abundant tubercles forming longitudinal series along dorsum, including lateral cushions; anterior eyes slightly larger than posterior ones; acicular lobe single, basaly swollen, tapered, blunt] . — 1 specimen, BMNH 1970.317, Royal Society Expedition to the Solomon Islands, 1965, Komimbo Bay, in coral boulders on reef platform, 18.VIII.1965, LMW coll. [40 mm long, 8 mm wide; slightly bent dorsally; antennae twice as long as wide; with oblique pigmented lines, somehow parallel but diverging from the middorsum, abundant tubercles forming longitudinal series along dorsum, including lateral cushions, better developed anteriorly; anterior eyes slightly larger than posterior ones, left posterior eye divided into 5 or 6 complete eyes; acicular lobe single, basaly swollen, tapered, blunt; pharynx fully exposed (5 mm long), dorsal papilla as wide as long] . — 4 specimens, BMNH 1970.318, Royal Society Expedition to the Solomon Islands, 1965, Graham Point, under boulders in silty sand, 21.IX.1965, MTL & LWM coll. [35-45 mm long, 5-7 mm wide; antennae twice as long as wide; colorless; tubercles in longitudinal series along dorsum, including lateral cushions, better defined in posterior chaetigers; anterior eyes slightly larger than posterior ones; acicular lobe single, basaly swollen, tapered, blunt] . — 2 specimens, BMNH 1970.320, Royal Society Expedition to the Solomon Islands, 1965, Graham Point, below boulders in shell gravel, 5.X.1965, LWM coll. [37-40 mm long, 5 mm wide; antennae twice as long as wide; longitudinal brownish lines and intersegmental lateral spots still visible; tubercles in longitudinal series along dorsum, including lateral cushions, better defined in posterior chaetigers; anterior eyes slightly larger than posterior ones; acicular lobe single, basaly swollen, tapered, blunt; pharynx partially exposed, dorsal papilla as wide as long in one specimen, the contrary in the other; oocyte strands, probably gonad fragments, over lateral surfaces; oocytes 100 µm in diameter] .

Australia. 2 specimens, AM W.2593, Low Isles, off Port Douglas , Queensland, VIII-IX.1928, G. P. Whitley & W. Boardman coll. [33-35 mm long, 6-7 mm wide; one turgid with prostomium intact and parapodia macerated, the other laterally bent, prostomium collapsed by pressure, better preserved; integument tuberculated; right parapodia of chaetigers 2 and 12 removed for observation (kept in vial); many chaetal blades lost; antennae minute, twice as long as wide; eyes blackish, anterior eyes marginal, looking as long as wide, twice larger than posterior rounded ones; acicular lobe single, basally swollen, tapered, blunt; about 22 chaetae per bundle] . — 1 specimen, AM W.3674, Port Curtis , Queensland, no further data [25 mm long, 5 mm wide; cemented ventrally over an acrylic plate, integument tuberculated, most chaetae broken, pharynx exposed; antennae minute, twice as long as wide; eyes colorless; acicular lobe single, blunt] . — 1 specimen, UF 1549 , Queensland, Heron Island , Harry’s canyon (-23.474366, 151.950466; 23°28’27.7176”S, 151°57’01.6776”E), 12-16 m depth, 21.XI.2009, S. McKeon coll. [39 mm long, 4 mm wide; brownish longitudinal, irregular thin bands throughout body, leaving middorsal polygonal or irregular, as wide as long pale areas over chaetal lobes region, in median and posterior regions with a middorsal darker band; body bent backwards, left posterior parapodia removed for molecular analysis, pharynx exposed, dorsal papillae twice as long as wide, tapered; antennae digitate, smaller than interocular distance; eyes brownish, anterior ones slightly larger than posterior ones; acicular lobe single, tapered; neurochaetal blades bidentate, upper ones very long, teeth minute, other ones with larger teeth, guard approaching distal tooth]. — 1 specimen, UF 1170 , Western Australia, Ningaloo Reef, S Green Hole Bommies (-22.40793, 113.7073; 22°24’28.5480”S, 113°42’26.2800”E), 7-8 m depth, 30.IV.2009, F. Michonneau coll. [26 mm long, 3 mm wide; almost without pigmentation, pale brownish longitudinal, irregular thin bands along a few anterior chaetigers; one right posterior parapodium removed for molecular analysis; integument rugose; antennae smaller than interocular distance; eyes dark brown, anterior ones slightly larger than posterior ones; acicular lobes single, long, tapered; neurochaetal blades with a few longer ones with small teeth, and shorter ones with lateral teeth, guard approaching distal tooth].

DISTRIBUTION. — Southern Japan to Australia including the Philippines, Indonesia, the Solomon Islands, and French Polynesia, in mixed bottoms from the intertidal to 53 m depth.

DIAGNOSIS. — Hesione with prostomium laterally curved; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore 2-3 times as long as wide; larger acicula blackish; acicular lobe single, tapered; neurochaetal blades bidentate, 3-4 times as long as wide; subdistal tooth smaller than distal one, with guards approaching distal tooth.

DESCRIPTION

Holotype, MNHW 293, macerated, damaged, 32 mm long, 6 mm wide. Body depressed, probably after fixation between glass slides; pharynx partially exposed, distorted ( Fig. 22A ); cirri macerated, chaetae without blades; neuraciculae thick, blackish, tapered; acicular lobes single, visible in several parapodia ( Fig. 22B ); posterior region transparent, macerated, tapered into a blunt cone ( Fig. 22C ); pygidial details not visible. Redescription based upon a sequenced specimen, UF 1772. Body complete, slightly bent ventrally, subcylindrical, slightly tapered posteriorly. Pigmentation: longitudinal sub-continuous brownish bands dorsolaterally, and discontinuous middorsally with an oval, as long as wide, pale area and shorter bands slightly darker ( Fig. 23C ); pigmentation extended into lateral cushions with paler areas coincident with lateral round areas, and darker intersegmental regions in ethanol. Integument granulose with adsorbed salt particles dorsally and ventrally, surface multituberculate, better defined along posterior region. Right parapodia of chaetigers 8-9 removed for molecular studies. Body 43 mm long, 6 mm wide.

Prostomium as long as wide, anterior margin projected anteriorly, lateral margins rounded, posterior margin exposed, deeply cleft along ¼ prostomial surface, longitudinal depression indistinct. Antennae digitate, 3-4 times as long as wide. Anterior eyes black, posterior ones brownish; anterior eyes slightly larger than posterior ones.

Tentacular cirri complete, variably contracted, longest ones reaching chaetiger 5. Lateral cushions barely projected; anterior ones divided into three sections, median and posterior segments with two sections or entire.

Parapodia with chaetal lobes digitate in anterior chaetigers ( Fig. 23D ), tapered in median ones ( Fig. 23E ); cirrostyle basally cylindrical, articulated entirely; dorsal cirri with tips lost, shorter than body width. Ventral cirri basally smooth, medially and distally regularly corrugated, surpassing chaetal lobes.

Neuraciculae pale in anterior chaetigers, blackish in median and posterior ones, two per neuropodium. Acicular lobe single, digitate to tapered.

Neurochaetae about 20 per bundle, blades at a certain angle from handle, blades bidentate, anterior parapodia with longer chaetal blades, 5-6 times as long as wide, median chaetigers with blades 3-4 times as long as wide; upper neurochaetae in anterior chaetigers with tiny denticles directed subdistally, other ones with lateral teeth, subdistal one smaller, guard approaching distal tooth.

Posterior region contracted, tapered into a blunt tube ( Fig. 23F ); pygidium swollen, anus terminal, with 12 thin, anal papillae.

Pigmentation

Living specimens brownish to reddish-brown ( Fig. 23A ). Pigmentation pattern including subcontinuous long, lateral bands, and shorter slightly darker middorsal bands, the latter interrupted by irregularly oval, as long as wide pale areas. Pigmentation extending into lateral cushions with coincident darker intersegmental areas with middorsal darker bands, and paler subcircular areas aligned with paler dorsal areas. Tentacular, dorsal cirri and neurochaetal lobes pale. Prostomium ( Fig. 23B ) with two short dark spots along anterior margins, and two smaller oblique central areas; anterior margin with transverse brownish bands, and two yellowish C-shaped bands arranged back to back ending in antennal bases.

Grube (1878: 102) indicated that the body was: “semitermes elongate, margaritacea, dorso transverse striato, per longitudinem virgis cinnaomemeis interruptis utrinque fer 7 ornato, confiniis segmentorum utrinque macula fusca inter dorsum medium et partes laterals sita distinctis.” [Transl. Subcylindrical, long, pearly-shiny, dorsum transversely striated, interrupted with about 7 cinnamon longitudinal discontinuous lines per side, distinct middorsal and latero-dorsal black spots positioned intersegmentally]. In the following page, he indicated that neuraciculae were black ( Grube 1878: 103). The original illustration is given here ( Fig. 24 ) and the anterior region has been enlarged for detecting finer details. The dorsal surface has large oval to fusiform, as long as wide, whitish or pearl-white areas, larger and better defined along anterior region ( Fig. 24A ) than in posterior region ( Fig. 24C ); antennae are tiny and anterior eyes are slightly larger than posterior ones ( Fig. 24B ). Also, neuraciculae are black, and were indicated as visible by transparency of the body wall. These features are visible in living specimens ( Fig. 25D ) but fade out quite soon after preservation.

This pigmentation pattern is seldom retained in aged specimens, as shown by one specimen collected in 1965. The anterior region has discontinuous dorsal longitudinal bands, somehow divergent in each segment, and a large oval middorsal area, and the blackish lateral intersegmental spots have almost completely faded out ( Fig. 25A ). As in the original illustration, the middorsal pale spots are less defined in the posterior region ( Fig. 25D ). This specimen has a rare anomaly on its left eyes because right eyes are typical for the species ( Fig. 25B ), but left eyes are not, especially the posterior eye which is replaced by 6-7 smaller eyes arranged into a curve line towards the lateral prostomial margin, and with some of them coalescent to the adjacent ones ( Fig. 25C ).

REMARKS

Hesione intertexta Grube, 1878 , restricted, resembles Hesione ceylonica Grube, 1874 , reinstated, after the key below. Their main difference is that in H. intertexta neurochaetal blades are 5-6 times as long as wide, whereas in H. ceylonica they are shorter, 3-4 times as long as wide. Dorsal pigmentation of living specimens also differs because in H. intertexta there are segmental transverse pale wide bands, whereas in H. ceylonica there are middorsal oval to foliose, and as long as wide pale areas. In the original description, Grube (1878: 103) gave measurements for a single specimen, hence the holotype, and indicated it was collected in Zamboanga (06°55’N, 122°05’E), Mindanao, in the southern region of the Philippines. This single specimen is housed in the Natural History Museum of the Wroclaw University, Poland. Another specimen, also collected by Semper in Palau, was deposited in the Zoologischen Museum, Berlin, and it is therein regarded as a syntype (ZMB 3813). This is incorrect after the Code ( ICZN 1999: art. 73.1.2), and it is herein regarded as a non-type specimen.

Hesione intertexta Grube, 1878 was characterised and illustrated by Wu et al. (1975: 76) for the Xisha Islands, and recently by Lee & Ong (2015: 204) for Singapore. These reports also indicated that acicular lobes are single, and their findings are herein corroborated based upon specimens originating from area close to the type locality. However, these authors did not indicate any variation on chaetal blade length or their dentition. As restricted herein, specimens belonging to H. intertexta have median chaetigers (6-8) with bidentate blades, with teeth well-defined, directed laterally. Those specimens provided with bidentate blades but with tiny teeth, directed distally or subdistally, present along median chaetigers, do not belong here.

In the original description and illustrations, Grube (1878) emphasised the combination of longitudinal pigment lines and transverse annulations or striae. These features are usually associated on dorsal surfaces but not extended into lateral cushions; however, for H. intertexta as originally described, even lateral cushions are shown as granulose, not smooth. A recent illustration by Lee & Ong (2015: 203) confirmed all these features. Consequently, the definition for H. intertexta must also include this integument feature.

The record by Pruvot (1930: 27-29) is questionable because he found acicular lobes double, and hence not really H. splendida nor H. intertexta , both having single acicular lobes.

Figures

FIG. 22. — Hesione intertexta Grube,1878,holotype,MNHW 293,restricted (mehtyl green pigmented):A, anterior region, dorsal view,pharynx everted (arrow points to left parapodium of chaetiger 4); B, chaetiger 4, left parapodium, upper view; C, posterior region, dorsal view. Scale bars: A: 0.8 mm, B: 0.3 mm, C: 1.4 mm.

FIG. 23. — Hesione intertexta Grube, 1878, restricted, non-type specimen, UF 1772, alive: A, dorsal view; B, same, anterior end, dorsal view; preserved; C, anterior region, dorsal view; D, chaetiger 2, left parapodium, anterior view (insets: upper to lower chaetal blades); E, chaetiger 8, left parapodium, anterior view (insets: upper to lower chaetal blades); F, posterior region, dorsal view; G, posterior end, close up, dorsal view. Scale bars: A, 3.1 mm; B, D, 0.8 mm, C, 1.8 mm; E, 0.7 mm; F, 2.5 mm, G, 0.6 mm.

FIG. 24. — Hesione intertexta Grube, 1878, non-type specimen, BMNH 1970.317: A, anterior region, dorsal view; B, prostomium, dorsal view; C, same, oblique dorsal view from the left side; D, posterior region, dorsal view. Scale bars: A, 2.8 mm; B, 0.3 mm; C, 0.4 mm; D, 1.5 mm.

FIG. 25. — Hesione intertexta Grube, 1878: A, anterior half of body, dorsal view; B, anterior end, dorsal view; C, posterior end, dorsal view (modif. after Grube, 1878; original without scale bars).