Hesione praetexta Ehlers, 1887

Salazar-Vallejo, Sergio I., 2018, Revision of Hesione Savigny in Lamarck, 1818 (Annelida, Errantia, Hesionidae), Zoosystema 40 (12), pp. 227-325 : 296-300

Hesione praetexta Ehlers, 1887 reinstated

( Figs 43-46 )

Hesione praetexta Ehlers, 1887: 147 , pl. 41, figs 5, 6. — Hartman 1938: 6.

Hesione proctochona – Horst 1921: 80 (non Schmarda, 1861).

Hesione picta ? – Uebelacker 1984: 28.36-28.38, fig. 28.34 (non Müller, 1858).

TYPE MATERIAL. — Gulf of Mexico, Florida. Two syntypes, MCZ 762, Dry Tortugas, RV Albatross , Sta. 11 (24°43’N, 83°25’W), 67 m depth, 14.XII.1877 [syntypes 18-19 mm long, 3.0- 3.3 mm wide; in poor condition, dried-out, most chaetae broken or without blades]. ADDITIONAL MATERIAL . — Northwestern Atlantic Ocean. Gulf of Mexico. Florida. — 2 specimens, ECOSUR 2920 , Florida Keys, 800 m SSW off Alligator Reef Light, 5-7 m depth, 30.IV.1960, WA Starck, T. Starck & HA Feddern coll. [16-20 mm long, 3 mm wide; no pigmentation; tiny antennae; pharynx papilla as long as wide; dorsal cirri multi-annulated; acicular lobes single, tapered]. — 1 specimen, UF 1060 , Monroe County, N of Florida Keys, Florida Bay (24.8899, -81.442816; 24°53’23.6400”N, - 081°26’34.1376”W), 12 m depth, 7.VI.2009, A. Anker, A. Bernis, C. Ewers, G. Hecht, M. Krisberg, S. McPherson, J. Zil coll. [22 mm long, 2.5 mm wide, 14 chaetigers, posterior region bent dorsally, some portions removed for molecular analysis; pigmentation pattern visible dorsally, lateral lobes almost without pigmentation; pharynx fully exposed; blades of chaetigers 3, 7 and 9 progressively smaller, teeth antero-lateral initially, progressively lateral; 4-11: 1 in chaetiger 3, 3-9: 1 in chaetiger 7 and 3-9: 1 in chaetiger 9] . — 1 specimen, UF 1063 , Monroe County, N of Florida Keys, Florida Bay (24.892683, -81.866116; 24°53’33.6588”N, 081°51’58.0176”W), 16 m depth, 7.VI.2009, A. Anker, A. Bernis, C. Ewers, G. Hecht, M. Krisberg, S. McPherson, J. Zil [15 mm long, 2.8 mm wide, body bent dorsally, pigmentation still visible as longitudinal irregular lines; two posterior left parapodia removed for molecular analysis; antennae tiny; pharynx not exposed; longest tentacular cirri reaching chaetiger 6; dorsal cirri basally straight; acicular lobe single, thin, tapered] . — 1 specimen, UF 1064 , Monroe County, N of Florida Keys, Florida Bay (24.892683, -81.866116; 24°53’33.6588”N, 081°51’58.0176”W), 16 m depth, 7.VI.2009, A. Anker, A. Bernis, C. Ewers, G. Hecht, M. Krisberg, S. McPherson, J. Zil [32 mm long, 3.5 mm wide, pigmentation pattern barely visible; no parapodia removed; blades of chaetigers 3, 7 and 9 progressively smaller, teeth antero-lateral, progressively lateral; 6-10: 1 in chaetiger 3, 3-9: 1 in chaetiger 7 and 4-6: 1 in chaetiger 9] . — 1 specimen, UF 1077 , W of St. Petersburg (27.441, -82.992333; 27°26’27.6000”N, 082°59’32.3988”W), 18-19 m depth, 11.XI.2007, G. Paulay coll. [35 mm long, 3.5 mm wide, unpigmented; acicular lobe with an upper tine tapered, thin, 3-4 times longer than lower rounded one] . — 1 specimen, UF 1874 , N of St. Petersburg , fossil patch reefs (29.028, -83.588666; 29°01’40.8000”N, 083°35’19.1976”W), 19-21 m depth, 12.III.2011, G. Paulay, M. Bernis, N. Evans, F. Michonneau, C. Thacker, R. Wiliams , A. Baeza coll. [14 mm long, 2 mm wide, 13-14 chaetigers (on each side); pigmentation faded off, visible along chaetigers 1-3; body without posterior region, pharynx not exposed; antennae tiny, conical; tentacular cirri without tips; acicular lobe single, thin, tapered] . — 1 specimen, UF 2569 , NNW of St. Petersburg, S of Big Bend area (28.68105, -84.3928; 28°40’51.7800”N, 084°23’34.0800”W), 27-32 m depth, 25.V.2012, J. Slapcinsky coll. [28 mm long, 4.5 mm wide; body distorted because of a lateral dissection to remove parapodia for molecular analysis; muscular anterior enteron exposed with long muscular fibers (photos); pigmentation pattern extended into lateral lobes, now faded out; acicular lobe single, long, tapered]. — 1 specimen, UF 2574 , NNW of St. Petersburg, S of Big Bend area (28.68105, -84.3928; 28°40’51.7800”N, 084°23’34.0800”W), 35-40 m depth, 25.V.2012, J. Slapcinsky coll. [54 mm long, 5 mm wide, pigmentation pattern visible along body, including anterior prostomial region; body wall broken by muscular enteric region; longest tentacular cirri reaching chaetiger 4; midbody chaetigers with dorsal cirri longer than body width, including parapodia; acicular lobe long, tapered, thin; blades of chaetigers 3, 7 and 9 progressively smaller, teeth antero-lateral progressively lateral; 4-11: 1 in chaetiger 3, 3-8: 1 in chaetiger 7 and 4-8: 1 in chaetiger 9]. — 1 specimen, UF 3173 , Palm Beach County, Peanut Island , western shore, rock jetty on sand (26.77488, -80.04844; 26°46’29.5680”N, 080°02’54.3840”W), 12.II.2013, J. Slapcinsky coll. [body 21 mm long, 3 mm wide; right parapodia of chaetigers 12-13 removed for molecular studies; pigmentation pattern visible, restricted to dorsal surface, not extended into lateral lobes; pharynx fully everted, dorsal papillae as long as wide; acicular lobe single, long, tapered] .

Bermuda. 1 specimen, MCZ 70247, Bermuda Sta. 501, 24.VIII.1903, Bermuda Institute of Ocean Sciences coll. [46 mm long, 5 mm wide; splendid specimen; prostomium anteriorly truncate, with a longitudinal furrow; antennae minute, blunt fusiform, slightly as long as wide; eyes almost colorless; pharynx not exposed; dorsal cirri basally smooth; acicular lobe with upper tine medially swollen, blunt, three times longer than smaller one, rounded; neurochaetal blades long and medium-sized, guards mostly eroded, some remaining approaching distal tooth; pygidium smooth, reddish, six blunt anal cirri] . — 1 specimen, USNM 32494 , no further data, T. Kincaid coll. [30 mm long, 4 mm wide; mature, some gonadic tubules protrudring throughout body wall in posterior segments; most cirri and chaetal blades lost; with an irregular anteroventral dissection, and left parapodium of chaetiger 10 previously removed; acicular lobe single, tapered] .

Bahamas. 1 specimen, MCZ 46395 , off Matthew Town, Great Inagua Island, 1.VIII.1938, McLean & Shreve coll. [35 mm long, 4 mm wide; mature, pharynx invaginated; prostomium with a deep longitudinal furrow; eyes of similar size, anterior ones slightly more separated, posterior ones duplicated; antennae minute, not visible dorsally; acicular lobe single, long tapered with a rounded shorter base; neurochaetae with long blades, guard approaching distal tooth; oocytes about 100 µm].

Gulf of Mexico. Yucatán, México. 1 specimen, ECOSUR 2921 , 1 km W off San Felipe lagoon mouth, 2 m depth, 18.II.1999, J. R. Bastida-Zavala & SISV coll. [23.5 mm long, 3 mm wide; pharynx not exposed, prostomium projected anteriorly; dorsal cirri multiarticulated; parapodia with chaetal lobes invaginated; acicular lobe single] . — 1 specimen, ECOSUR OH-592, Ría Lagartos , 1 km W off lagoon mouth, 3 m, 14.VI.2009, L. F. Carrera-Parra & SISV coll. [10 mm long, 1.5 mm wide; pharynx everted, margin smooth; no pigmentation] .

Caribbean Sea. México. Quintana Roo. Isla Contoy. 1 specimen, ECOSUR 2922 , Playa Camping , rocky shore, 0.5 m depth, 13.II.1999, SISV coll. [36 mm long, 4 mm wide; with an anterior dissection; no pigmentation; antennae not seen; pharynx papilla not visible, dissected; dorsal cirri multi-annulated; acicular lobes single, tapered].

Punta Nizuc . 1 specimen, ECOSUR 2292 , outer reef, 4 m depth, under rock, 10.II.2001, L. F. Carrera-Parra & SISV coll. [26 mm long, 3 mm wide; right parapodia of chaetigers 4, 9 and 15 removed; no pigmentation; antennae not seen; pharynx papilla rounded, as long as wide; dorsal cirri multi-annulated basally and throughout it; acicular lobes single, tapered; neurochaetal blades bidentate]. — 1 specimen, UMML351 , RV Gerda, Arrowsmith Bank, Sta. 951 (21°06’N, 86°28’W), 249 m depth, 28.I.1968 [30 mm long, 5 mm wide; body laterally bent, distorted, prostomium with tiny antennae; pygidium with anal cone, anal cirri minute; parapodial lobes deeply invaginated; dorsal cirri smooth; chaetae lost; acicular lobes single, contracted] .

Cuba. 1 specimen, ZMUC 2426 , Yversen coll., no further data [macerated, enigmatic fixation resulting in pale soft body and whitish, brittle cirri; body 27 mm long, 4.5 mm wide; acicular lobe single, tapered ].

Puerto Rico. 1 specimen, MCZ 46415, La Parguera, 19.I.1969, L. S. Roberts coll. [11.5 mm long, 2 mm wide; slightly distorted; most chaetae broken; prostomium anteriorly cleft, with a longitudinal furrow; eyes dark brown, anterior ones twice as large as posteriors; dorsal cirri basally smooth; acicular lobes with an upper tine large, medially swollen, 3 times longer than lower one; few chaetal blades remaining, mostly long; pygidium smooth, with 5-6 blunt anal papillae] .

Haiti. 1 specimen, ZMH-P 1292a, Port-au-Prince, Kepperschmidt coll., no further data [15 mm long, 2 mm wide, colorless; acicular lobe single, basally swollen, digitate].

Jamaica. 1 specimen, LACM 10166 , Saint Ann Parish, St. Ann’s Bay, Hofstra University Marine Laboratory Cove , in Acetabularia , 0 - 10 m depth, 25.V-3.VI.2006, K. Rawlinson, M. Bolanod, A. DuPont, A. Allan, J. Dunn & L. Harris coll. [splendid specimen, used for Redescription] . — 1 specimen, ZMH-P 6787, Kingston, 24.IX.1905, A. Gagzo coll. [25 mm long, 4 mm wide; slightly bent backwards; colorless; right chaetal lobe of chaetiger 7 previously removed; most cirri on site, most neurochaetal blades lost; antennae blunt, minute about twice as long as wide; eyes brownish, anterior ones twice as large as posterior ones; acicular lobe single, long, tapered] .

Saint-Thomas. 1 specimen, ZMUC 2429 b, 1860, Krebs coll., no further data [28 mm long, 3 mm wide, macerated, colorless; left parapodium of chaetiger 8 removed for observation (kept in container); acicular lobe single, thick, blunt; neurochaetal blades bidentate, guard approaching distal tooth].

Guadeloupe. 1 specimen, MNHN-IA-PNT102 (formerly jar 914), Sta. 4B 600, no further data [22 mm long, 3 mm wide; dark pinkish because of Bengal Rose stain; macerated, most dorsal cirri and neurochaetal blades lost, distorted posteriorly; several parapodia previously removed; acicular lobe single, thin, very long; about 20 neurochaetae per bundle; not listed by Amoureux (1985) but probably based upon the same study].

Colombia. 1 specimen, ECOSUR 2294 , RV Pilsbury, Sta. 772 (12°20’N, 71°55’W), 11 m depth, 29.VII.1968 (21 mm long, 3 mm wide; pharynx not exposed; eyes depigmented; dorsal cirri multiannulated; acicular lobes single, long, tapered].

Trinidad and Tobago. 1 specimen, MCZ 46401 , E. Deichmann coll. [19 mm long, 2 mm wide, partially dehydrated; prostomium slightly projected anteriorly; pharynx not exposed; eyes almost colorless; dorsal cirri annulated basally; acicular lobe long tapered, some parapodia with a smaller round to triangular smaller lower lobe; neurochaetal blades long to medium-sized; pygidium barely rugose].

Venezuela. 1 specimen, ECOSUR 2925 , mature female, ENE off Margarita Island , RV Pilsbury Sta. 712 (11°09’N, 63°18’W), 26 m depth, 19.VII.1968 [36 mm long, 4.5 mm wide; antennae minute; eyes dark brown, anterior ones larger, slightly more separated than posterior eyes; dorsal cirri multi-articulated; acicular lobe double, upper lobe longer, taperer, ventral lobe, blunt; oocytes 90-100 µm] .

Brazil. 1 specimen, MNHN-IA-PNT103 (formerly jar 879), RV Calypso , off Pernambuco coast, Sta. 23 (08°19’S, 34°39’W), 75 m depth, 21.XI.1961 [27 mm long, 4 mm wide; slightly macerated, integument shiny with pale brown longitudinal, irregular lines; antennae minute, slightly as long as wide; eyes difussely pigmented, anterior and posterior lateral eyes close to each other; acicular lobe double, blunt, upper tine digitate, 5 times longer than lower, round one; neurochaetae about 20 per bundle, blades bidentate, distal tooth larger, guard approaching distal tooth] . — 5 specimens, MNHN- IA-PNT101b (formerly jar 888a), RV Calypso, Sta. 19 (03°49.7’S, 32°26’W), 31 m depth, 18.XI.1961 [17-26 mm long, 2.5-4.0 mm wide; macerated, integument shiny with pale brown longitudinal, irregular lines, especially visible along chaetigers 1-3, and in posterior chaetigers of 1 specimen; antennae minute, slightly as long as wide; eyes almost colorless, anterior eyes twice larger than posterior ones; acicular lobe double, blunt, upper tine digitate, 5 times longer than lower, round one; neurochaetae about 20 per bundle, blades bidentate, distal tooth larger, guard approaching distal tooth] . — 1 speci- men, MNHN-IA-PNT101c (formerly jar 888b), RV Calypso, Sta. 7 (03°50’S, 33°54’W), 54- 47 m depth, 17.XI.1961 [16 mm long, 2 mm wide; colorless juvenile, dried-out but not brittle, with salt particles adsorbed forming flat, squarish spots throughout body; acicular lobe projected in some chaetigers with upper tine very long; not dissected to avoid further damage].

DISTRIBUTION. — Western Atlantic, from Bermuda to Northern Brazil, in mixed or rocky bottoms in 0-249 m water depth.

DIAGNOSIS. — Hesione with prostomium rectangular, or slightly curved laterally; parapodia with dorsal cirri basally cylindrical, dorsal cirrophore twice as long as wide; larger acicula blackish; acicular lobe single, long, tapered or blunt, lower tine rounded, small; neurochaetal blades bidentate, 4-7 times as long as wide; subdistal tooth smaller than distal one, with guards approaching distal tooth.

REDESCRIPTION

Best preserved specimen, LACM 10166, mature, complete, subcylindrical, tapered posteriorly, with some traces of original pigmentation: longitudinal, irregular lines throughout body ( Fig. 43A, B ) in ethanol; most cirri and neurochaetal blades on site; right parapodium of chaetiger 8 removed (kept in vial). Body 33 mm long, 3 mm wide.

Prostomium slightly as long as wide, anterior margin slightly projected anteriorly, lateral margins rounded, posterior margin deeply cleft, about ¼ as long as prostomial length, longitudinal depression barely detected ( Fig. 43B ). Antennae minute, left one visible, ovoid, barely as long as wide, about 1/3 as long as interocular distance. Eyes brownish, anterior ones slightly larger than posterior ones.

Tentacular cirri long, thin, twisted, longest ones reaching chaetiger 4. Lateral cushions low, barely projected (specimen relaxed before preservation), surface smooth.

Parapodia with chaetal lobes slightly as long as wide, truncate; dorsal cirri with cirrophores about twice as long as wide ( Fig. 43C ); cirrostyle basally cylindrical, annulated, articulated medially and distally, as long as body width, including parapodia. Ventral cirri smooth, surpassing chaetal lobe.

Neuraciculae blackish, tapered, larger one markedly thicker and darker than smaller one. Acicular lobe double, upper tine digitate, 3 times longer than lower, round one ( Fig.44C [inset]).

Neurochaetae about 20 per bundle, blades bidentate, 4-7 times as long as wide ( Fig. 43D ), blades at a certain angle from handle, decreasing in size ventrally, each with smaller subdistal teeth, guard approaching distal tooth.

Posterior region tapered into a blunt cone, dorsal surface rugose ( Fig. 43E ); pygidium smooth, anus with 5 low, blunt papillae.

Pharynx not exposed. Oocytes about 100 µm in diameter.

Variation

Lateral cushions can be more projected if the body was more contracted ( Fig. 44A, C, D ). The prostomium can become markedly as wide as long ( Fig. 43B ), but the size proportions of eyes are less variable. In some specimens, the upper tine of acicular lobe can be digitate, 4 times longer than the lower one ( Fig. 43F ), or it can be tapered and longer in other specimens ( Fig. 44E ). Neurochaetal blades are 4-11 times as long as wide in anterior chaetigers, and reduce their proportions to 3(4)-8(9) median chaetigers ( Fig. 44F ).

Pigmentation

Body with dorsal, longitudinal, irregular, discontinuous wide brown bands ( Fig. 45A ), barely expanded into lateral cushions, but not into pygidium. Tentacular, dorsal cirri and chaetal lobes pale, cirrophores yellowish. Prostomium ( Fig. 45B ) with brownish marginal bands, continuous along anterior margin, interrupted along posterior one, over a redbrownish background. Longitudinal bands longer along a few anterior chaetigers, each as long as segmental length, often with irregular, slightly darker limits, leaving a middorsal spot unpigmented, except in chaetiger 1, and in last chaetiger where the spot is larger; in median and posterior chaetigers with two additional lateral spots. Middorsal pale spots connected by a thin, middorsal brownish line, better defined along medial and posterior chaetigers. Longitudinal bands progressively smaller in median ( Fig. 45C ) and posterior chaetigers, becoming 1/6-1/10 as long as segmental length, as rounded, irregular spots

REMARKS

Hesione praetexta Ehlers, 1887 reinstated, has been regarded as a potential junior synonym of H. picta Müller, 1858 by Hartman (1938: 6), or of H. proctochona Schmarda, 1861 by Horst (1921: 80), and even Ehlers doubted about its independent status. In his original description, he thought pigmentation differences could be related to sexual dimorphism ( Ehlers 1887: 147). At the same time, however, Ehlers indicated and illustrated some other differences besides pigmentation patterns in the diagnosis, his drawings reproduced herein as Figure 46 , such as the presence of single acicular lobe ( Fig. 46A ), against double in H. vittigera (syn. H. picta ), and longer, thinner chaetal blades ( Fig. 46B ), instead of shorter, thicker in H. vittigera . These differences have been found consistent and not modified during ontogeny ( Fig. 1 ), such that they are herein regarded as sufficient to separate H. praetexta from the other common Grand Caribbean species, H. picta Müller, 1858 .

In the key below, H. praetexta resembles H. helenensis n. sp. because both have digitate acicular lobes. They differ in cirrostyles bases and on the size of neurochaetal blades and guards. In H. praetexta cirrostyles are basally cylindrical, blades are 4-6 times as long as wide, and guards approach distal tooth, whereas in H. helenensis n. sp. cirrostyles are basally swollen, blades are 4-5 times as long as wide, and guards approach subdistal tooth.

Figures

FIG. 43. — Hesione praetexta Ehlers,1887,non-type specimen,LACM 10166:A, anterior region,dorsal view; B, same,close-up; C, chaetiger 8, right parapodium, anterior view (inset: acicular lobe); D, same, neurochaetal blades; E, posterior region, dorsal view; F, another non-type specimen, MCZ 46395, chaetiger 6, right parapodium, anterior view. Scale bars: A, 1.6 mm; B, 1 mm; C, 0.4 mm; D, 40 µm; E, 1.2 mm; F, 0.1 mm.

FIG. 44. — Hesione praetexta Ehlers, 1887, non-type specimen, ECOSUR 2292: A, anterior end, dorsal view; B, head, dorsal view; C, posterior end, dorsal view; D, pydidium, dorsal view; E, chaetiger 9, right parapodium, posterior view (inset: acicular lobe); F, same, upper, medial and lower neurochaetal blades. Scale bars: A, 1.7 mm; B, E, 0.4 mm; C, 1.8 mm; D, 0.8 mm; F, 40 µm.

FIG. 45. — Hesione praetexta Ehlers,1887, non-type specimen,LACM 10166: A, dorsal view; B, anterior end, dorsal view; C, chaetigers 8–11, dorsal view. Scale bars: A, 3 mm; B, 0.7 mm; C, 0.8 mm. Photos: Leslie Harris, LACM.

FIG. 46. — Hesione praetexta Ehlers,1887: A, parapodium from a middle-body segment; B, same,tip of neurochaetal tip (modif.after Ehlers,1887,scale bars missing in original).

FIG. 1. — Range variation of neurochaetal blades length: width ratios in three chaetigers (3,7,9),observed in two different Hesione Savigny in Lamarck,1818 species: A, H. picta Müller, 1858 from Florida (18 mm: UF 825, 26 mm: UF 826, 32 mm: UF 1593); B, H. praetexta Ehlers, 1887 from Florida (22 mm: UF 1060, 32 mm: UF 1064, 54 mm: UF 2574).