Leocrates giardi Gravier, 1900

Salazar-Vallejo, Sergio I., 2020, Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae), Zootaxa 4739 (1), pp. 1-114 : 55-57

Leocrates giardi Gravier, 1900

Figs 29 , 30

Leocrates giardi Gravier, 1900: 180–185 , Textfigs. 46–52, Pl. 10, Figs 17–19 ).

Leocrates claparedii: Fauvel 1919: 371 ; Fauvel, 1933: 44-45 (non Costa in Claparède, 1868).

Leocrates diplognathus: Fauvel 1955 a: 105 (non Monro, 1926).

Type material. Red Sea, Gulf of Aden. Six syntypes ( MNHN 289), some collected in Aden (12°46’25” N, 46°01’35” E) by Dr. Jousseaume in 1893, others in Djibouti (11°36’ N, 43°09’ E), Djibouti, by Drs Jousseaume and Coutière in 1897, kept in the same container; no further data.

Additional material. Red Sea. Gulf of Suez. One specimen ( MNHN A419), no further data [20 mm long, 3 mm wide]. Saudi Arabia. Two specimens ( MNHN A71), Mission Bonin-Perez, Côtes d’Arabie, Sta. 48, 1901, no further data [11–13 mm long, 2 mm wide]. Two specimens ( MNHN A71b), Mission Bonin-Perez, Côtes d’Arabie, Sta. 53, 1901, no further data [15–16 mm long, 2–3 mm wide]. One specimen ( MNHN A372), Farasan Archipelago, Abulat Island (19°58’ N, 40°07’ E), Sta. 5, NW off islet North, in Porites , 0–5 m, 1951–1952, Drach, Cherbonnier & Mercier, coll. [12 mm long, 1.8 mm wide]. One specimen ( UF 3586), Farasan Islands, Zahrat Durakah (16°50’09.24” N, 42°18’22.68” E), 2–6 m, fringing reef, slope around sand, 11 Mar. 2013, A. Anker, P. Norby & G. Paulay, coll. [21 mm long, 3 mm wide]. One specimen ( UF 3499), Farasan Islands, Mahama Island, fringing slope (16°29’21.12” N, 41°56’39.48” E), 4–17 m, sand, reef rubble, 9 Mar. 2013, A. Anker, P. Norby & G. Paulay, coll. [data used for variation].

Description. Syntypes (MNHN 289) distorted, partially dehydrated, most cirri missing, many chaetae broken ( Fig. 29 A–C). Body obconic, blunt anteriorly, tapered posteriorly, dorsum darker along anterior chaetigers (1–6/8), or dark throughout dorsal surface; some middle parapodia previously removed. Body 18–23 mm long, 1.5–3.0 mm wide, 16 chaetigers.

Prostomium wider than long in smaller syntypes ( Fig. 29A ), as long as wide or slightly longer than wide in larger ones ( Fig. 29B, C ); slightly wider anteriorly (depending on pharynx eversion), lateral margins straight. Lateral antennae with ceratophores distinct, lateral antennae as long as prostomium (longer in smaller syntypes), as long as palps or slightly longer than them. Palpophores 2–3 times longer than palpostyles. Median antenna tapered, short, not reaching prostomial anterior margin, inserted between posterior eyes.

Eyes brownish, anterior ones slightly larger, about 1 / 10 as wide as prostomial width, missing in a smaller syntype, circular in another, emarginate in two specimens, and semilunar in two others, larger and more distant to each other than posterior round ones (semilunar in two syntypes).

Nuchal organs lobes horizontal C-shaped, visible dorsally in most syntypes; lateral ciliated bands dorsally visible in two syntypes. Tentacular cirri missing (reaching chaetiger 4 in original description). Lateral cushions low, entire, longitudinal striae barely visible.

Pharynx fully exposed in one small syntype ( Fig. 29D ), partially exposed in another medium-sized one. Anterior margin with about 20 regular constrictions per side. Lateral vesicles not seen. Jaws single, yellowish, upper jaw twice larger than lower one, tapered, inserted slightly ahead of lower jaw.

Dorsal cirri remaining in a few segments, without tips, shorter than body width. Chaetigers 1–4 without notochaetae; notochaetae present along chaetigers 5–16, about 20 per bundle, sometimes arranged in longitudinal fans, or as a bundle, subdistally denticulate, denticles fine. Notacicular lobes tapered; neuracicular lobes blunt, conical slightly longer than wide, sometimes as wide as long ( Fig. 29E ); ventral cirri surpassing neurochaetal lobe. Neurochaetae about 20 per bundle, blades bidentate, decreasing in size ventrally, 3–10 times longer than wide, guards approaching subdistal tooth ( Fig. 29F, G ).

Posterior region tapered. Preanal segment with dorsal cirri missing. Pygidium with anus terminal, anal cirri missing.

Oocytes about 100 µm in diameter, visible in smaller and larger syntypes.

Variation. One specimen (UF 3499) complete, straight. Body pale up to chaetiger 5, thereafter brownish; 16 mm long, 2 mm wide, 15 chaetigers (posterior end removed for molecular analysis; right parapodium of chaetiger 8 removed for parapodial features). Lateral antennae longer than prostomium, slightly longer than palps ( Fig. 30A ); palpophores twice longer than palpostyles; median antenna broken, inserted between posterior eyes. Eyes brownish, anterior ones twice larger than posterior ones. Longest tentacular cirri reaching chaetiger 7. Pharynx fully exposed ( Fig. 30 A–C), lateral vesicles tapered, upper and lower jaws exposed, hyaline, upper one twice larger than lower one. Notochaetae along chaetigers 5–15, many broken, denticulation fine; neurochaetae about 20 per bundle ( Fig. 30D ), blades 2–9 times longer than wide, guards approaching subdistal tooth ( Fig. 30D , insets). Oocytes not seen, coelom full of damaged testis fragments and spermatids.Additional specimens 11–21 mm long, collected in subtidal environments (2–17 m depth). Two specimens (UF 3499, 3586) smaller than syntypes (16–21 mm long) had pharynxes fully exposed, showing lateral vesicles, each with well-defined tips (tapered).

Remarks. Leocrates giardi Gravier, 1900 resembles L. claparedii (Costa in Claparède, 1868) from the Mediterranean Sea by having prostomia wider anteriorly, notacicular lobes tapered, and middle chaetigers with about 20–30 neurochaetae. They differ, however, by the shape of notacicular and neuracicular lobes, and by the relative length of neurochaetal blades. In L. giardi notacicular lobes are tapered, neuracicular ones are as long as wide, and neurochaetal blades are 3–10 times longer than wide, whereas in L. claparedii notacicular lobes are blunt, neuracicular ones are wider than long, and blades are 2–8 times longer than wide.

The redefinition of L. giardi by Pettibone (1970: 219–221, Figs 17–19 ) must be discontinued because she did not study type material or topotype specimens, and the specimens she illustrated do not belong to Leocrates , as herein restricted, but to Dalhousia , as redefined above.

Distribution. Red Sea, subtidal mixed bottoms (2–17 m depth).

Figures

FIGURE 17. Lamprophaea cuprea Grube, 1867, reinstated, largest non-type specimen (USNM 19194). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Chaetiger 8, right parapodium, anterior view, MGS (insets: notacicular and neuracicular lobes). D. Same, neurochaetae. Scale bars: A: 1.4 mm, B, C: 0.3 mm, D: 80 µm.

FIGURE 18. Lamprophaea longicirrata (Treadwell, 1902), new combination, holotype (USNM 15915), MGS. A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Anterior end, ventral view. D. Chaetiger 10, right parapodium, anterior view (insets: longest and shortest neurochaetal blades, and notacicular lobe). Scale bars: A: 0.7 mm, B, C: 0.6 mm, D: 0.9 mm.

FIGURE 19. Lamprophaea ockeri n. sp., holotype (LACM 10143). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Chaetiger 8, left parapodium, anterior view, MGS. D. Same, neurochaetal blades including longest and shortest ones. Scale bars: A: 1.2 mm, B: 0.8 mm, C: 0.5 mm, D: 0.1 mm.

FIGURE 29. Leocrates giardi Gravier, 1900, syntypes (MNHN 289). A. Smaller syntype, anterior region, dorsal view. B. Medium-sized syntype, anterior region, dorsal view. C. Larger syntype, anterior, region dorsal view. D. Smaller syntype, anterior region, ventral view. E. Chaetiger 7, left parapodium, anterior view (inset: notacicular lobe). F. Upper neurochaetal blade. G. Lower neurochaetal blades. Scale bars: A: 0.8 mm, B: 1.1 mm, C: 1.2 mm, D: 1 mm, E: 0.5 mm, F: 80 μm, G: 60 μm.

FIGURE 30. Leocrates giardi Gravier, 1900, non-type specimen (UF 3499). A. Anterior region, dorsal view, MGS. B. Same, right lateral view, SAS. C. Same, ventral view. D. Chaetiger 8, right parapodium, anterior view (insets: smaller and longer neurochaetal blades). Scale bars: A: 0.6 mm, B: 0.7 mm, C: 0.8 mm, D: 0.4 mm.