Hesione splendida Savigny in Lamarck, 1818

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 309-313

Hesione splendida Savigny in Lamarck, 1818

( Figs 52-54 )

Hesione splendida Savigny in Lamarck, 1818: 316 . — Savigny 1822: 40, pl. 3, fig 3.1-3.7. — de Blainville 1825: 443; 1828: 482; 1830, pl. 17, fig. 1 (copied from Savigny). — Audouin & Milne-Edwards 1833: pl. 15, figs 1-3. — de Quatrefages 1866: 95-96. — Day 1967: 228, fig. 11.2A-C. — Solís-Weiss et al. 2004: S5.

Hesione ehlersi Gravier, 1900: 175-179 , figs 42-45, pl. 9, figs 14, 15. — Wehe & Fiege 2002: 57 (n. syn.). — Solís-Weiss et al. 2004: S5.

Hesione pantherina – Fauvel 1918: 332, 333; 1927: 417. — McIntosh 1924: 15, 16; 1925: 40-41, pl. 5, fig. 4 (upside down). — Day 1951: 21 (non Risso 1826).

Hesione reticulata – Stagl et al. 1996: 34, table 2 (non von Marenzeller, 1879).

TYPE MATERIAL. — Western Indian Ocean , Red Sea. Lectotype of Hesione splendida , MNHN-IA-TYPE0140, designated herein, originally collected in the Suez Gulf, M. Botta coll., no further data. Paralectotype of H. splendida , MNHN-IA-TYPE0139, smashed down (probably by labels), partially dehydrated, Île-de-France ( Mauritius), M. Mathieu coll. [55 mm long, 6 mm wide, 15 chaetigers; pharynx exposed, posterior end lost; no other morphological feature can be noticed (right parapodium of chaetiger 8 removed) acicula black, thick, single; acicular lobe single, blunt; neurochaetae about 40 per bundle, neurochaetal blades mostly lost, remaining ones bidentate, subdistal tooth minute, guard approaching subdistal tooth]. Syntypes of Hesione ehlersi , MNHN 287 , Djibouti, 1897, H. Coutière, coll. [used for Redescription].

ADDITIONAL MATERIAL. — Red Sea. 1 specimen, BMNH 1926.11 .12.10, Cambridge Suez Canal Expedition, Suez, Sta. T 8, 9.XII.1924, no further data [21 mm long, 4 mm wide; body straight, medially wider, integument smooth, colorless; antennae digitate, 2-3 times as long as wide; right parapodium of chaetiger 8 removed for observation (kept in vial); acicular lobe single, tapered; neurochaetae most broken, blades bidentate, subdistal tooth smaller than distal one; guards broken, approaching subdistal tooth] . — 2 specimens, BMNH 1926.11.12.11/12, Cambridge Suez Canal Expedition , Suez , Sta. T 8, 4.XII.1924, no further data [one distorted by compression, the other straight; straight one 30 mm long, 6 mm wide; both medially wider, integument smooth, colorless; antennae digitate, 2-3 times as long as wide; acicular lobe single, tapered; neurochaetae with blades bidentate, subdistal tooth smaller than distal one; guards, if entire, approaching distal tooth] . — 1 specimen, BMNH 1926.11 .12.14, Cambridge Suez Canal Expedition , Suez, Sta. K 9, 25.X.1924, no further data [29 mm long, 4.5 mm wide; bent dorsally, medially wider, integument smooth, colorless; antennae digitate, 2-3 times as long as wide; acicular lobe single, tapered; neurochaetae most without blades; pharynx exposed, dorsal papilla minute, slightly as wide as long] . — 1 specimen, BMNH 1926.11 .12.15, Cambridge Suez Canal Expedition , Suez , Sta. El Ferdane, 27.X.1924, no further data [22 mm long, 5 mm wide; medially wider, integument smooth, colorless; antennae digitate, 2-3 times as long as wide; right posterior eye duplicated, almost fused to anterior right eye; several chaetal lobes invaginated; acicular lobe single, tapered; neurochaetae complete, blades bidentate] . — 1 specimen, BMNH 1926.11 .12.17, Cambridge Suez Canal Expedition , Suez , Sta. P 1, 13.XII.1924, no further data [21 mm long, 4 mm wide; body depressed, medially wider, integument smooth, colorless; antennae digitate, 2-3 times as long as wide; all chaetal lobes exposed; acicular lobe single, tapered, if fully extended, about as 1/10 as long as neurochaetae] . — 1 specimen, BMNH 1926.11 .12.18, Cambridge Suez Canal Expedition , Suez , Sta. T 9, dredge, 6.XII.1924, no further data [20 mm long, 2.5 mm wide; body slightly bent dorsally, integument smooth, annulated, colorless; antennae digitate, 2 times as long as wide; anterior eyes obliquely as long as wide; chaetal lobes variably invaginated; acicular lobe single, tapered; pharynx exposed, apillae small, as long as wide] . — 2 specimens, MNHN-IA-PNT 91t (formerly jar 70), Djibouti Bay, in Ircinia cavities, with amphinomids, eunicids and nereidids, 13.I.1904, C. Gravier coll. [27-31 mm long, 3-4 mm wide; body pearly gray, with tiny black spots irregularly distributed along body; body slightly distorted, one with pharynx fully exposed, dorsal papilla round, as long as wide; neuraciculae tapered; acicular lobe single, tapered or blunt] . — 1 specimen, MNHN-IA-PNT107 (formerly jar 419), Ayna Massa, Gulf of Suez, no further data [52 mm long, 6.5 mm wide (right parapodia of chaetigers 7 and 16 removed for observation, kept in vial); integument rugose, shiny; antennae tapered, 2-3 times as long as wide; eyes rounded, anterior ones darker, slightly larger than posterior ones; pharynx exposed, dorsal papilla slightly as wide as long; acicular lobe single, digitate; neurochaetae about 30 per bundle, neurochaetal blades bidentate, subdistal tooth smaller, guard approaching distal tooth] . — 1 specimen, MNHW unnumb., Ehrenberg coll. [28 mm long, 4 mm wide; macerated but integument still shiny, smooth; pharynx fully everted with three muscular rings; eyes colorless, visible after short-term staining with methyl-green; antennae short, only right one left, digitate, 2.0-2.5 times as long as wide, tip broken; neuraciculae black, tapered; acicular lobe single; neurochaetal blades transparent, body] . — 2 specimens, NHMW 575, Pola Red Sea Expedition 1895-1898, no further data [20-30 mm long, 2-3 mm wide; partially dried out; one pale brown, the other grayish, both with pharynx exposed; integument shiny; antennae shorter than posterior eyes diameter; antennae minute, digitate, about twice as long as wide, difficult to be seen because of pharyngeal folds; parapodia with neuraciculae blackish, tapered, single; acicular lobe single; most neurochatal blades lost]. — 7 specimens, ZMB 534 , and one slide, Egypt, Gulf of Suez, Janub Sina’, El Tor, Ehrenberg coll. [27-33 mm long, 4.0- 5.5 mm wide; specimens probably collected in different dates because they differ in their condition; one is too macerated, whereas two others are in much better condition; four paler, two other darker; body antennae digitate, often eroded, as long as interocular distance; anterior eyes about twice as large as posterior ones; neuraciculae thick, blackish, tapered; acicular lobe single; neurochaetal blades bidentate, most broken, guards, if complete, approaching distal tooth] . — 5 specimens, ZMB 535 , and one slide (535a), Egypt, Gulf of Suez, Janub Sina’, El Tor, Ehrenberg coll. [30-46 mm long, 4-7 mm wide; variably macerated, one whitish, three grayish, one brownish with scattered white spots like bacteria or fungi growing on it; parapodial lobes invaginated, neuraciculae blackish, thick, tapered; acicular lobes single, tapered; neurochaetal blades bidentate, guards, if complete, approaching distal tooth] . — 1 specimen, ZMB 3805 , and one slide made by Dr Bergmann, no further data [57 mm long, 6 mm wide; dissected throughout the body to study inner organs; prostomium removed; acicular lobe double, short, rounded, upper tine about twice as long as lower one; neurochaetal blades bidentate, anterior ones with teeth smaller, guard approaching subdistal tooth] . — 1 specimen, ZMB 3806 , and one slide, Grube Collection, Ehrenberg coll. [25 mm long, 5 mm wide; macerated; some left parapodia previously removed; integument shiny, grayish; pharynx exposed, dorsal papillae rounded, slightly as wide as long; antennae digitate, 4-5 times as long as wide; eyes colorless; acicular lobe single, long, tapered; neurochaetal blades bidentate, guard approaching subdistal tooth] .

Western Indian Ocean. Oman. 1 specimen, UF 46 , Masirah Island, 2 to 4 km S of SE tip of Island, coarse sand and rocks, 20-22 m depth, 8.XI.1999, G. Paulay coll. [35 mm long, 7 mm wide; colorless, integument areolated, not tuberculated as in H. intertexta ; antennae minute, smaller than interocular distance; eyes brownish, anterior eyes slightly larger than posterior ones; dorsal cirrophore 3-4 times as long as wide, cirrostyle cylindrical basally, annulated; ventral cirri articulated, longer than chaetal lobe; acicular lobe single, wide basally, digitate, tapered distally; neurochaetal blades bidentate, guard approaching distal tooth in anterior chaetigers as well]. — 1 specimen, UF 48 , Masirah Island, South-southwest tip of Masirah , 100 m from shore, rocks and reef, under rocks, 1-7 m depth, 6.XI.1999, G. Paulay coll. [46 mm long, 5.5 mm wide; body stiff, bent ventrally, without pigmentation; acicular lobe single, wide basally, digitate, tapered distally]. — 1 specimen, UF 410 , Qurm Beach , near Muscat (23.626, 58.481; 23°37’33.6000”N, 058°28’51.6000”E), 0-1 m depth, 26.I.2005, V. Bonito, M. Claereboudt & G. Paulay coll. [32 mm long, 4 mm wide; body laterally bent, without pigmentation; acicular lobe single, wide basally, digitate, tapered distally] . — 2 specimens, MNHN-IA-PNT91 (formerly jar 70), Mission Bouvier-Perez, Sta. 50, Banc Rák-as-Zakoum , 6.4 km off Oman, 8-12 m depth, 19.III.1901 [38-48 mm long, 4-8 mm wide; slightly damaged, many chaetae broken; body grayish, integument markedly shiny, areolated in anterior and posterior regions; acicular lobes single, tapered]. — 2 specimens, MNHN-IA-PNT91 (formerly jar 70), Mission Bouvier-Perez, Sta. 53, probably near to station 50, but without further data [dried-out; too brittle to be measured; acicular lobes single and tentatively regarding in this species] . Zanzibar. 1 specimen, MCZ 1215 , 25.III.1862, C. Cooke coll. [59 mm long, 8 mm wide; body distorted by pressure in container, with many amphinomid chaetae; integument opaque; prostomium distorted; antennae ovoid, smaller than interocular distance; eyes dark brown, anterior ones twice as large as posterior ones; cirrophores 4 times as long as wide; dorsal cirri basally articulated; acicular lobe single, digitate; neurochaetae brownish, very abundant, most with long or medium-sized blades, subdistal tooth smaller; most guards broken, those entire approach distal tooth; pygidium rugose, anus projected, without anal cirri] . — 2 specimens, MCZ 46506 , 25.III.1863, C. Cooke coll. [49-57 mm long, 6-8 mm wide; body macerated, integument transparent; most chaetal lobes invaginated; chaetae dark brown; one chaetal lobe from the larger specimen was removed for observation (kept in vial); one thick black acicula; most with long or very long blades, subdistal tooth smaller, guard approaching distal tooth] . Madagascar. 4 specimens, UCO HES 11 , Expedition MD/08, Sta. 6, Banc Walters , no further data [23-39 mm long, 3-4 mm wide; damaged, most cirri and chaetal blades lost; colorless, eyes without pigmentation; acicular lobe single; blades bidentate, guard approaching subdistal tooth] . — 1 specimen, UF 737 , Nosy Iranja , off N side, 3-4 m depth, 24.V.2008, G. Bakary, F. Michonneau, G. Paulay & T. Werner coll. [34 mm long, 4 mm wide; body almost colorless, pigmentation resembling H. intertexta by having granulose or regularly rugose dorsal integument along posterior body half, and weak longitudinal lines and some triangular spots between lateral cushions, but anterior neurochaetal blades without tiny denticles, pointing distally; acicular lobe single, blunt, about 20 neurochaetae per bundle; blades bidentate, guard straight approaching distal tooth]. Persian Gulf. 1 specimen, SMF 19491, near PTL 9, MSGR 1993 , 7.II.1993, M. Apel coll. [32 mm long, 4 mm wide; colorless, bent laterally; antennae globose, 1.5 times as long as wide; eyes barely pigmented, anterior ones twice as large as posterior ones; most cirri and neurochaetal blades broken; right parapodium of chaetiger 9 removed for observation (kept in vial); acicular lobe single, tapered; neurochaetal blades bidentate, subdistal tooth smaller; guards mostly broken, a few left approaching distal tooth] .

DISTRIBUTION. — Western Indian Ocean , from the Persian Gulf to Madagascar, in 0 -22 m depth, in mixed bottoms.

DIAGNOSIS. — Hesione with prostomium curved laterally; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore twice as long as wide; larger acicula blackish; acicular lobe single, long, blunt or slightly swollen distally, lower tine missing; neurochaetal blades bidentate, 5-9 times as long as wide; subdistal tooth smaller than distal one, with guards approaching distal tooth.

DESCRIPTION

Lectotype of Hesione splendida , MNHN-IA-TYPE0140, 41 mm long, 6 mm wide; slightly macerated, longitudinally dissected anteriorly over the left side above parapodia ( Fig. 52A ), and another lateral dissection in the posterior third of body; ante- rior and posterior ends collapsed; anterior region macerated, prostomial features unclear ( Fig. 52B ); right parapodium of chaetiger 8 removed for observation; dorsal cirrophore macerated, about three times longer than wide ( Fig. 52C ), ventral cirri eroded, surpassing chaetal lobe; parapodial lobe contracted; neuraciculae black, one very thick, another one markedly thinner, only visible after dissecting parapodia; acicular lobe single, tapered ( Fig. 52C [inset]); most neurochaetal blades lost, those remaining eroded, blades bidentate, guards broken bases visible in a few blades ( Fig. 52C [inset]); posterior region tapered into a conical pygidium ( Fig. 52D ), anal papillae not seen; mature, larger oocytes about 100 µm in diameter.

Syntypes of H. ehlersi , MNHN-IA-TYPE0287, complete, some laterally bent, integument areolated ( Fig. 53A, C ), partially dehydrated, colorless in ethanol; most without dorsal cirri, chaetal blades broken, longest one with a longitudinal mid-ventral dissection, running through 14-15 chaetigers. Body subcylindrical, tapered posteriorly, 31-44 mm long, 3-4 mm wide.

Prostomium as long as wide, anterior margin truncate ( Fig. 53B ) to slightly projected anteriorly ( Fig. 53D ), lateral margins rounded, progressively wider, posterior margin exposed, with a deep depression, as long as 1/3 prostomial length, longitudinal depression very shallow, barely detected. Antennae minute, digitate, as long as interocular distance, or 1-2 times as long as wide. Several syntypes with eyes retaining brownish pigmentation; anterior eyes larger, sometimes twice larger than posterior ones.

Tentacular cirri and development unknown (originally illustrated as reaching chaetiger 5). Lateral cushions low, barely projected, most divided into anterior and posterior sections.

Parapodia with chaetal lobes truncate, as long as wide ( Fig. 53E ); dorsal cirri with cirrophores 2-3 times as long as wide ( Fig. 53F ), cirrostyles basally cylindrical, annulated, medially annulated, distally articulated (originally illustrated as completely annulated or articulated). Ventral cirri smooth throughout its length, surpassing chaetal lobe.

Neuraciculae blackish, larger one visible by transparency. Acicular lobes single, long (5-6 times as long as wide), blunt, slightly capitate in some parapodia ( Fig. 54E [inset]), to tapered in the same specimen ( Fig. 53F [inset]).

Neurochaetae about 25 per bundle, handles honey-colored, blades bidentate, at a certain angle from handle, many lost, remaining ones decreasing in size ventrally, 5-9 times as long as wide, each with smaller subdistal tooth, guards, if complete, approaching or slightly surpassing subdistal tooth ( Fig. 53G [insets]).

Posterior region tapered into a blunt cone; pygidium smooth, anus projected with 7 low, blunt papillae.

Pharynx not exposed. Oocytes not seen.

Variation

In syntypes of H. ehlersi (MNHN-IA-TYPE0287), anterior eyes can be slightly larger to twice larger than posterior ones. Antennae are difficult to see, partially because they are small, partially because bodies are partially dehydrated. Dorsal cirri shorter than body width (excluding parapodia). Acicular lobes are almost always single; rarely, especially when the upper tine is very short, a lower shorter tine can be noted. Anterior chaetigers with longest blades, teeth tiny, distal one larger, laterally directed; guards mostly broken, those remaining approaching distal tooth. In better preserved specimens, the integument is areolated ( Fig. 54A, F ), eyes brownish, anterior ones larger and antennae are wider medially, 2-3 times as long as wide, although the posterior furrow is not visible ( Fig. 54B ); dorsal cirrophores are twice as long as wide, and acicular lobes are single and become narrower in the first body third ( Fig. 54C, D ), whereas neurochaetal blades are thinner and have smaller teeth in anterior chaetigers in comparison to those present in following chaetigers ( Fig. 54E ).

REMARKS

Hesione splendida Savigny in Lamarck, 1818 was described with two specimens (syntypes); they belong to the same species despite their distant localities: Mauritius Island, MNHN-IA- TYPE0139, and Red Sea, MNHN-IA-TYPE0140). Both have a very thick black acicula and another one, markedly thinner, and their acicular lobes are single. Because one of the syntypes, MNHN-IA-TYPE0139, is in poor condition, being smashed and partially dehydrated, the other one is herein designated as the lectotype for H. splendida Savigny in Lamarck, 1818 . Because Savigny (1822: 40) indicated a slight difference in the length of neurochaetal blades, and because they tend to be shorter in posterior chaetigers or, in the same chaetal bundle, if they are in lower portion. This proposal complies with the Code ( ICZN 1999: art. 74.7, recomm. 74B).

For the corresponding remarks of H. ehlersi, Gravier (1900: 179) preferred to compare it to other species instead of contrasting it against H. splendida , which had been also described fom the Red Sea. Gravier indicated it had no pigmentation pattern, a feature which is usually non-diagnostic, especially if it fades off soon in ethanol. Because the only other species described from the same region was H. splendida Savigny in Lamarck, 1818 , it is enigmatic why these two species were not compared to each other, especially because the syntypes of the latter were in Paris, where Gravier used to work. Gravier thought his new species resembled H. pantherina Risso, 1826 , described from the Mediterranean Sea, at least regarding prostomial features ( Gravier 1900: 179). However, Gravier noted that regarding parapodial features H. ehlersi differs from H. pantherina (probably referable to H. sicula ) because it has a single acicular lobe, whereas in the latter a double lobe is present. However, this feature is also present in H. splendida and these two species are herein shown to be synonyms, something other authors have anticipated. Gravier also indicated that his H. ehlersi resembled H. praetexta Ehlers, 1887 , and H. vittigera Ehlers, 1887 because all were supposed to have single acicular lobes. This is incorrect. A single acicular lobe is present only in H. praetexta , not in H. vittigera (junior synonym of H. picta , see above).

Other species provided with single, tapered acicular lobes are H. eugeniae and H. intertexta , and the type of neurochaetal blades could easily separate them. In H. eugeniae the guard extends beyond distal tooth, which is a rather unique feature present only in another species (described above as H. osbornae n. sp.). Then, the most similar species to H. splendida is H. intertexta by having similar prostomial and chaetal features with blades bidentate, with subdistal tooth minute and guard approaching distal tooth, but they differ because in the latter blade teeth can be directed distally in upper bundle chaetae (especially common in smaller specimens), but usually teeth are laterally directed and in either case, the guard approaches the distal tooth.

The specimens from Zanzibar (MCZ 46506) have a single, thick black acicula, despite the fact their bodies and parapodia are very large; this could be a useful difference among similar species but parapodial slides must be thoroughly compared. Further, in these specimens the guards, if entire, approach the distal tooth, and not just the subdistal tooth as illustrated by Day (1967). Because guards are very brittle, this is not regarded as a diagnostic difference, pending the study of specimens from Mozambique and Madagascar, which were apparently used by Day for his illustrations and description; it must be noted that he indicated a single conical acicular lobe ( Day 1967: 228). Further, guards can be broken in a few chaetal blades per bundle; they cannot be confused with those chaetae deprived of guards because there is an evident marginal depression where the guard used to be.

The affinities between H. ehlersi and H. intertexta Grube, 1878 deserve clarification. Wehe & Fiege (2002: 57) indicated that H. ehlersi has been regarded as a junior synonym of H. pantherina Risso, 1826 by Fauvel (1953b: 104), or of H. splendida Savigny in Lamarck, 1818 by Pleijel (1998: 158). Dimitri Costa reached the same conclusion as Pleijel after studying the type series, as indicated by the labels left with the specimen. It can be concluded that H. ehlersi is a junior synonym of H. splendida , but as indicated above, H. pantherina is a distinct species.

The record for Western Australia by Hartmann-Schröder (1979: 84, ZMH-P 16538) is a posterior fragment of another hesionid, or from a syllid; it has pale, thin, tapered neuraciculae, and the neurochaetal blades are thin, unidentate; these features do not match with the nominal form.

Figures

FIG. 52. — Hesione splendida Savigny in Lamarck, 1818, lectotype, MNHN-IA-TYPE-140: A, dorsal view, note the longitudinal eccentric dissection; B, anterior region, dorsal view; C, chaetiger 8, right parapodium, anterior view (insets:close-ups of acicular lobe and tips of blades); D, posterior region,oblique dorsal view. Scale bars: A, 2.3 mm; B, 1.7 mm; C, 0.2 mm; D, 1 mm.

FIG. 53. — Hesione splendida Savigny in Lamarck,1818,syntypes of H. ehlersi Gravier,1900,MNHN-IA-TYPE0287: A, largest syntype,anterior region,dorsal view; B, same, anterior end, dorsal view; C, second largest syntype, anterior region, dorsal view; D, same, anterior end, dorsal view; E, largest syntype, chaetiger 9, left parapodium, anterior view (inset: acicular lobe); F, same, chaetiger 10, left parapodium, anterior view (inset: acicular lobe, folded); G, same, neurochaetae (insets: blade tips). Scale bars: A, 1 mm; B, D, E, 0.5 mm; C, 1.4 mm; F, 0.3 mm; G, 0.2 mm.

FIG. 54. — Hesione splendida Savigny in Lamarck, 1818, non-type specimen, UF 46: A, anterior region, dorsal view; B, prostomium, dorsal view (arrows point to antennae); C, chaetiger 2, right parapodium, anterior view, an oocyte released (inset: acicular lobe); D, chaetiger 6, right parapodium, anterior view, oocytes inside parapodial coelom (inset: acicular lobe); E, neurochaetal blades, left one from chaetiger 2, others from chaetiger 6 (insets: close-up of tips); F, posterior region, dorsal view. Scale bars: A, 2 mm; B, 0.3 mm; C, 0.4 mm; D, 0.7 mm; E, 60 µm; F, 0.5 mm.