Hesione ceylonica Grube, 1874

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 241-245

Hesione ceylonica Grube, 1874 reinstated

( Figs 7-9 )

Hesione ceylonica Grube, 1874: 327 . — Willey 1905: 266.

Hesione intertexta – Monro 1937: 270. — Fauvel 1953b: 105 (non Grube, 1878).

Hesione pantherina – Gravier 1900: 179-180, pl. 10, fig. 16. — Fauvel 1911: 374-376, fig. 6; 1919b: 370, 371; 1927: 417; 1932a: 60, 61; 1953b: 104, 105, fig. 49A-G; 1955: 105. — Aziz 1938: 23, 24, pl. 3, fig. 6, pl. 7, fig. 23, pl. 7, fig. 46. — Fishelson & Rullier 1969: 58, 59 (non Risso, 1826).

Hesione splendida – Augener 1926: 451, 452. — Day 1973: 343, 344. — Misra 1999: 145, 146 (non Savigny in Lamarck, 1818).

TYPE MATERIAL. — Indian Ocean , Sri Lanka. Neotype, ZMH- P 9951 , and one specimen labelled paraneotype, ZMUC 2432, Trincomalee (08°34’00”N, 81°14’00”E), 2.IX.1889, K. Friestedt coll. [specimen labelled paraneotype complete, 46 mm long, 5 mm wide; anterior end distorted by compression into small container, laterally bent; chaetae from left parapodium of chaetiger 10, and right parapodium of chetiger 11 previously removed; most cirri broken medially; most chaetae broken; body integument smooth along chaetigers 2-10, others with 7-9 longitudinal, continuous keels; lateral cushions with longitudinal ridges; dorsal cirri smaller than body width].

ADDITIONAL MATERIAL. — Indian Ocean. Sri Lanka ( Ceylon). 1 specimen, BMNH 1874.10 .2.10, 1874, E. W. H. Hodsworth coll. (complete, slightly macerated, longitudinal lines barely visible along last three chaetigers; left parapodia of chaetigers 5, 6, and right parapodium of chaetiger 8 previously removed; acicular lobes single; body 24 mm long, 3.5 mm wide) . — 1 specimen, MNHN- IA-PNT90b [formerly jar 372], Mannar , no further data (complete, slightly macerated, longitudinal lines barely visible along last three chaetigers; left parapodia of chaetigers 5, 6, and right parapodium of chaetiger 8 previously removed; acicular lobes single; body 24 mm long, 3.5 mm wide) .

India. 2 specimens, BMNH 1922.12 .22.2, Madras, no further data [45-50 mm long, 6 mm wide; distorted, variably damaged, integument with longitudinal ridges in first few chaetigers, lateral cushions with longitudinal ridges in posterior chaetigers; antennae digitate, 2-3 times as long as wide; larger specimen with a longitudinal, dorsal dissection through chaetigers 1-15; right parapodia of chaetigers 7 and 10 previously removed; acicular lobe single, tapered; neurochaetae most broken or without blades] . — 2 specimens, BMNH 1926.4 .30.115, Ramesvaram, Gulf of Mannar , E. Thurston coll., no further data [one macerated, with strange, destructive dissections along and across body; right parapodia of chaetigers 7 and 15 (one of each specimen) previously removed; body colorless, complete one 44 mm long, 5 mm wide; well-defined longitudinal ridges at least in posterior chaetigers; lateral cushions with longitudinal ridges; acicular lobe single, tapered] .

Gulf of Aden. 7 specimens, MNHN-IA-PNT91 (formerly jar 70) , Aden (12°48’N, 45°02’E), Yemen, 1893, N. Jousseaume coll. [6 specimens macerated, the other in better condition, with dorsal longitudinal bands now only visible in chaetiger 1; best preserved specimen with a longitudinal dissection ventrally] .

Oman. 1 specimen, BMNH 1937.9 .2.104, John Murray Expedition, Sta. 53, off Ras Al-Mabrakah, dredge, 13.5 m depth, 2.XI.1933 [35 mm long, 5 mm wide; colorless, bent ventrally, cirri slightly macerated; left parapodia of chaetigers 7 and 8 previously removed; antennae digitate, 2-3 times as long as wide; eyes brownish, anterior ones slightly larger than posterior ones; acicular lobe single, basally swollen, tapered, blunt; ventral cirri surpassing chaetal lobe] . — 1 specimen, UF 408 , SSE tip of Bar Al Hikman Peninsula (20.337833, 58.387883; 20°20’16.1988”N, 058°23’16.3788”E), 4-5 m depth, V. Bonito, M Claereboudt & G. Paulay coll. [22 mm long, 3 mm wide, 15 chaetigers left; posterior end removed for molecular analysis; pigmentation barely visible; acicular lobe single, tapered, blunt].

Persian Gulf. Kuwait. 1 specimen, BMNH 1938.5.7.16, harbor, gift from the Indian Museum [partially dehydrated; 38 mm long, 5 mm wide; colorless, integument tuberculated, lateral cushions with longitudinal ridges in posterior chaetigers; acicular lobe single, tapered] .

Saudi Arabia. 1 specimen, SMF 9248, Jubail Research Center, Project Marine Sanctuary for the Gulf Region 1991, leg. D. Fiege, 9.XII.1991 [27 mm long, 4 mm wide; colorless, slightly dehydrated, dorsal and tentacular cirri dehiscent, several lost; right parapodium of chaetiger 9 removed for observation (kept in vial); body slightly bent laterally, antennae ovate, twice as long as wide; eyes brownish, anterior ones slightly larger than posterior ones; acicular lobe single, basally swollen, tapered, blunt; ventral cirri surpassing chaetal lobe; neurochaetal blades bidentate, subdistal tooth smaller, guards mostly broken, if entire, approaching distal tooth] .

Red Sea. 1 specimen, BMNH 1926.11.12.9, Cambridge Suez Canal Expedition , Suez , no further data [41 mm long, 9 mm wide; body slightly bent dorsally, integument smooth, pigmentation pattern as slightly discontinuous longitudinal, irregular bands throughout body; antennae digitate, 4-5 times as long as wide; right parapodium of chaetiger 13 removed for observation (kept in vial); acicular lobe single, tapered, a few with bifid tips; neurochaetae most broken, blades bidentate, subdistal tooth smaller than distal one; guards broken, approaching subdistal tooth; pharynx partially exposed, dorsal papilla slightly as long as wide]. — 1 specimen, BMNH 1926.11 .12.16, Cambridge Suez Canal Expedition , Suez, Toussonu, 29.XI.1924, no further data [17 mm long, 4.5 mm wide; body distorted, bent ventrally, integument smooth, discontinuous barely-pigmented longitudinal, irregular bands throughout anterior 5-6 chaetigers; antennae broken, left one truncate, right one tapered, 3-4 times as long as wide; acicular lobe single, tapered; neurochaetae variably damaged, blades bidentate, subdistal tooth smaller than distal one; pharynx partially exposed, dorsal papilla slightly as wide as long] . — 3 specimens, BMNH 1926.11.12.19/21, Cambridge Suez Canal Expedition , Suez, St.K 2, 17.X.1924, no further data [19-25 mm long, 4-5 mm wide; body distorted, variably damaged, bent dorsally, integument smooth, discontinuous barely-pigmented longitudinal, irregular bands, better defined along anterior chaetigers; antennae broken; acicular lobe single, tapered; neurochaetae variably damaged, parapodia not examined; pharynx variably exposed, dorsal papilla visible in 1 specimen, slightly as wide as long] . — 1 specimen, BMNH 1926.11 .12.22, Cambridge Suez Canal Expedition , Suez, Sta. K 1, 16.X.1924, no further data [17 mm long, 4.5 mm wide; integument smooth, discontinuous barely-pigmented longitudinal, irregular bands throughout anterior 5 chaetigers; antennae broken, tapered, 2-3 times as long as wide; acicular lobe single, tapered, if fully extended about ¼ as long as neurochaetae; neurochaetae variably damaged, not observed; pharynx partially exposed, dorsal papilla slightly as wide as long] . — 1 specimen, BMNH 1956.8 .8.13, Gulf of Aqaba , Eilat, Israel, no further data [40 mm long, 8 mm wide; integument smooth, showing some longitudinal, feebly defined ridges, colorless; gonads exposed by fracture of body wall in chaetigers 6, 12 and 14; antennae digitate, 5-6 times as long as wide; left parapodium of chaetiger 6 previously removed; acicular lobe single, tapered, if fully extended about 1/6 as long as neurochaetae; neurochaetae variably damaged, not observed; oocytes about 100 µm in diameter] . — 3 specimens, SMF 2642 , 1827 , E. Rüppell coll., id. as H. marmorata [31-38 mm long, 3.0- 4.5 mm wide; colorless, turgid, neurochaetal blades mostly lost, remaining blades eroded; left parapodium of chaetiger 11 removed for observation (kept in container); anterior eyes twice as large as posterior ones (colorless in larger specimen); antennae digitate, twice as long as wide; lateral cushions barely projected, entire, smaller specimen with longitudinal ridges in posterior chaetigers; acicular lobe single, tapered; neurochaetal blades and handle articulation tips severely eroded] .

Saudi Arabia. 5 specimens, RMNH 282 , Jeddah (21°32’36”N, 39°10’22”E), 1881, no further data [30-40 mm long, 4-5 mm wide; 2 specimens macerated, the other three in better condition including one with pharynx partially exposed, and retaining some pigmentation dorsally; eye size variable; acicular lobe single, conical to globose, depending on contraction of chaetal lobe] . — 1 specimen, UF 3486 , Farasan Islands , Abu Lad (16.79772, 42.19910; 16°47’51.7920”N, 042°11’56.7600”E), fringing reef slope with abundant Sargassum , 1-10 m depth, 10.III.2013, A. Anker, P. Norby & G. Paulay coll. [26 mm long, 2.5 mm wide; body with 11-13 dorsal discontinuous irregular brownish longitudinal bands, separated by pale areas along chaetal lobes in chaetigers 2-9, less defined posteriorly; prostomium with brownish anterior band, and a thinner band running over eyes converging over the nuchal organs median furrow; antennae shorter than interocular distance; eyes brownish, anterior eyes darker, about twice as large as posterior ones; longest tentacular cirri reaching chaetiger 6; dorsal cirri with cirrophores twice as long as wide, cirrostyle basally cylindrical, annulated, as long as body width (without parapodia); ventral cirri irregularly contracted, longer than chaetal lobe; acicular lobe single, tapered, blunt; neurochaetae about 20 per bundle; blades long, bidentate, upper ones with tiny denticles, directed subdistally, most with lateral teeth, subdistal tooth smaller, guard approaching subdistal tooth; posterior end tapered into a blunt cone; pygidium with pigmentation bands, anus projected, anal papillae not exposed] .

Mozambique. 2 specimens, BMNH 1955.4.1.100/101, Capetown University Expedition to Morrumbene, 1954, Morrumbene Estuary, Sta. 155K, San José Mission, Cymodocea bed, 17.VII.1954, no further data [45-48 mm long, 5-6 mm wide; damaged, distorted, most cirri and chaetal blades lost; almost colorless, longitudinal lines or elongated spots visible along posterior chaetigers; eyes blackish, anterior eyes slightly larger than posterior ones; acicular lobe single; blades bidentate, guard approaching distal tooth; pharynx partially exposed, dorsal papilla as long as wide] .

DISTRIBUTION. — Sri Lanka throughout the Western Indian Ocean, including the Red Sea, in intertidal to shallow subtidal bottoms (10 m depth), in seaweeds ( Cymodocea , Sargassum ), or among pearl oysters.

DIAGNOSIS. — Hesione with prostomium laterally curved; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore 1.5 times as long as wide; larger acicula blackish; acicular lobe single, tapered; neurochaetal blades bidentate, 5-6 times as long as wide; subdistal tooth smaller than distal one, with guards approaching distal tooth.

REDESCRIPTION

Neotype, ZMH-P9951, complete, without pigmentation in ethanol, slightly distorted, pharynx almost fully exposed ( Fig. 7A ); integument with 9-11 longitudinal series of small tubercles, better defined in medial segments, reduced to 6-7 series in last three chaetigers; left parapodium of chaetiger 7 removed for observation (kept in vial). Body medially wider, tapered posteriorly, 26 mm long, 3.5 mm wide.

Prostomium ovoid, as wide as long, anterior margin projected anteriorly, lateral margins rounded, progressively expanded, posterior margin barely covered by anterior margin of tentacular segment, posterior furrow as long as 1/5 prostomial length; longitudinal depression well-defined separating prostomium into two lateral sections. Antennae minute, ovate, twice as long as wide ( Figs 7B , 8B ). Eyes barely pigmented, anterior ones slightly larger, and more separated from each other than posterior ones.

Tentacular cirri lost on right side, left side with curled, annulated cirri, tips eroded, longest one reaching chaetiger 4. Lateral cushions very low, most with longitudinal crests throughout their surface.

Parapodia with chaetal lobes slightly as long as wide, truncate ( Fig. 7C ); dorsal cirri with cirrophores smooth, about twice as long as wide; cirrostyles basally cylindrical, annulated throughout their length. Ventral cirri regularly corrugated, surpassing chaetal lobe.

Neuraciculae two, blackish, larger one thicker, tapered. Acicular lobe single, tapered, triangular to digitate, basally swollen ( Fig. 7C [inset]); thinner, slightly shorter than chaetal lobe width in other specimens ( Fig. 8C ).

Neurochaetae about 30 per bundle, blades at a certain angle from handle, bidentate, slightly decreasing in size ventrally, 5 times as long as wide (5-6: 1 in other specimens, Fig. 8C [insets]); blades with smaller subdistal tooth, and larger distal tooth, guard approaching distal tooth ( Fig. 7D ).

Posterior region tapered into a truncate cone ( Figs 7E , 8D ); pygidium with anus terminal, anal papillae rounded, small.

Pharynx partially exposed, distal ring shorter, ciliated, medial ring three times longer, basal ring shorter than distal one; dorsal papilla round, slightly depressed, as long as wide.

Oocytes not seen.

Pigmentation

Body with dorsal, longitudinal, irregular, subcontinuous wide brown bands ( Fig. 9A, D ), over a whitish, pinkish or purplish background, especially pigmented along posterior region ( Fig. 9C, F ). Preserved specimens with 11-12 longitudinal bands, interrupted segmentally ( Fig. 8A ), discontinuities less defined posteriorly ( Fig. 8D ), brownish pigmentation continued into lateral cushions as large brownish spots just before chaetal lobes, and 1-3 as long as wide, lateral spots; larger spots progressively separated into three or more smaller spots in medial and posterior chaetigers. Prostomium reddish, eyes black, large ( Fig. 9B ) almost fused to each other, or small ( Fig. 9E ), distant to each other. Tentacular, dorsal cirri and chaetal lobes pale (bluish hint in figures 9E, F due to blue background); dorsal cirrophores deep yellowish, especially along medial and posterior chaetigers. Longitudinal bands solid, or with a paler central area, sometimes regularly interrupted by a pale transverse region along chaetigers 2-9 ( Fig. 9A ), following segments with three irregular spots, one middorsal, two lateral, or paler transverse areas poorly defined ( Fig. 9E ).

REMARKS

Hesione ceylonica Grube, 1874 , reinstated, resembles H. uchidai n. sp. because both have neurochaetal blades up to 6 times as long as wide. They differ, as indicated in the key below, because in H. ceylonica the acicular lobes are triangular or basally swollen, and neurochaetal blades are 5-6 times as long as wide, whereas in H. uchidai n. sp. the acicular lobes are digitate, and the neurochaetal blades are 4-6 times as long as wide. Another difference is in the pigmentation pattern of living specimens: H. ceylonica has discontinuous longitudinal bands, interrupted by dorsal segmental, transverse pale, wide bands, whereas H. uchidai n. sp. has continuous longitudinal bands, together with discontinuous reddish brown bands, alternating with pale areas middorsally.

Gravier (1900: 179, pl. 10, fig. 16) hesitated when he identified some Red Sea specimens as H. pantherina . He characterised and illustrated the dorsal regular longitudinal bands, and their discontinuity in segmental limits, leaving pale areas, that can be found in fresh specimens of H. ceylonica , but not in H. pantherina , where longitudinal lines are interrupted or made as a succession of closely packed spots, and transverse pale areas are thinner. Willey (1905) studied some recently collected specimens and indicated there were dorsal longitudinal bands or streaks, but gave no further details. Augener (1926: 451) concluded that H. ceylonica must be included, together with H. ehlersi Gravier, 1900 , as junior synonyms of H. splendida . In this conclusion he was partially correct because H. splendida and H. ehlersi are synonyms (see below), but H. ceylonica differs at least regarding its pigmentation pattern, as originally indicated by Grube (1874). However, for older specimens having probably no pigmentation, other differences are needed to separate the species. In H. ceylonica , after some photos by Anna Zhadan, the dorsum has brownish discontinuous bands over a pale reddish or yellowish background, especially because cirrophores are yellow, with small lateral darker areas just before the chaetal lobe region, and all cirri are pale; there are pale areas middorsally along most chaetigers. On the contrary, in H. pantherina , the dorsum has reddish discontinuous bands over a pale pink background, middorsal pale areas are much smaller without any darker spot before the chaetal lobe regions, and most cirri are dark pink or reddish, including their cirrophores.

Grube (1874: 327) detailed the pigmentation pattern: “Ex fulvescente rosea, splendens, leviter iridicolor, dorso medio e longitudinae linis fusciribus subviolaceis fere 11 contiguis, postremum versus evanesentibus striato, partibus lateralibus sepositis, e longitudine sulcatis” (Transl.: Bright pink, yellowish-brown, iridescent. Dorsum with 11 longitudinal sub-purple, subcontinuous bands, posteriorly faded off, laterally furrowed). This is surprisingly accurate despite the fact Grube did not collect the specimen, and if these observations were based upon a preserved specimen, it might be enigmatic how specimen was fixed. The answer is that the living pigmentation pattern was supplied together with the specimens by E. W. H. Holdsworth ( Grube 1874: 325-326). Holdsworth was not an amateur collector; he was a fine ornithologist who made a catalogue of Sri-Lankan birds ( Holdsworth 1872), and found some time to collect marine invertebrates such as polychaetes and sponges ( Bowerbank 1873), providing details about their pigmentation along with specimens. Parapodial details have not been compared before. In both H. ceylonica and H. pantherina , as herein restricted, there is a single, tapered, blunt acicular lobe.

Frankfurt specimens from the Red Sea, SMF 2642, are notworthy because of several reasons. For example, they were named as “ H. marmorata ” by Eduard Rüppell, their collector, and this name indicates a pigmentation pattern which would set it apart from the other Red Sea species, H. splendida , which is grayish. The specimens were probably collected when Rüppell visited the Gulf of Aqaba in 1822, as indicated in his biography in Wikipedia, but deposited in the Frankfurt collections once he returned to Germany in 1827. Despite its antiquity, the body and appendages are in a remarkable preservation state, and only neurochaetal blades are lost, or severely eroded, including handles tips, which suggests an alternative, abrasive preservation method differing from the one relying only in alcohol.

On the other hand, Hesione ceylonica Grube, 1874 belongs in the group of species having longitudinal pigmented bands dorsally and the proposal of a neotype, its redescription and illustrations are required to clarify the taxonomic status of the species ( ICZN 1999: art. 75.3.1), especially because most have been regarded as synonyms of H. pantherina Risso, 1828 , a Mediterranean species. The above description and remarks, together with the key to species, include the differentiating features for the species and are enough to recognize the species (Art. 75.3.2-3). No type material was deposited in Berlin ( Hartwich 1993) or in Wroclaw ( Wiktor 1980), where most of Grube´s type specimens are; in fact, the Berlin Museum has two type lots only from the six species described from Sri Lanka in the same publication ( Grube 1874): Nereis (Platynereis) festiva (ZMB Q 3502) and Sabella fuscotaeniata (ZMB Q 5222) no type specimens could be found for this species in Berlin or Wroclaw Museums ( ICZN 1999: art. 75.3.4). Further, the neotype is consistent with known features of the species, as indicated in the original description and subsequent publications on it ( ICZN 1999: art. 75.3.5). Both the neotype and the specimen labelled paraneotype were collected in the same locality in Trincomalee, Northeastern Sri Lanka; the original type locality was not indicated but they might have been collected in Aripo, close to Mannar, in Northwestern Sri Lanka, because some sponges were collected from there by the same person ( Bowerbank 1873). Along the coast, there are about 270 km appart from these two localities, but because they are at about the same latitude, bordered by coral reefs, they are regarded as belonging to the same ecological coastal unit ( ICZN 1999: art. 75.3.6; Spalding et al. 2007). Finally, both the neotype and the specimen labelled paraneotype are deposited in the museums of Copenhagen and Berlin respectively ( ICZN 1999: art. 75.3.7); these two are long-standing, recognised institutions.

Figures

FIG. 7. — Hesione ceylonica Grube,1874,neotype,ZMH-P 9951: A, anterior end,dorsal view; B, prostomium, dorsal view (arrow points to left antenna);C, chaetiger 7, left parapodium, anterior view (inset: close-up of acicular lobe); D, same, two neurochaetal blades (insets: tips of blades); E, posterior region, dorsal view. Scale bars: A, E, 1.4 mm; B, 0.3 mm; C, 0.4 mm; D, 25 µm.

FIG. 8. — Hesione ceylonica Grube, 1874, UF 3486: A, anterior end, dorsal view; B, head, dorsal view (arrow points to left antenna); C, chaetiger 8, right parapo- dium,anterior view (insets,two upper and one lower neurochaetal blades); D, posterior region,dorsal view.Scale bars:A,1 mm; B, 0.3 mm;C, 0.6 mm; D, 0.9 mm.

FIG. 9. — Hesione ceylonica Grube, 1874, living specimens, Musfat Al-Ahmadi, Kuwait: A, dorsal view; B, anterior end, dorsal view; C, chaetigers 10-14, dorsal view;D, another specimen,right lateral view; E, anterior end, dorsal view; F, posterior end, dorsal view. Scale bars: A,4 mm;B, E, 1.3 mm; C, 1.9 mm; D, 3.8 mm; F, 1.7 mm (Photos: A-C, E, F, Anna Zhadan; D, Valery Skryabin).