Dalhousia atlantica McIntosh, 1885

Salazar-Vallejo, Sergio I., 2020, Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae), Zootaxa 4739 (1), pp. 1-114 : 22-25

Dalhousia atlantica McIntosh, 1885

Figures 4 , 5 A–C, 9, 10

Dalhousia atlantica McIntosh, 1885: 186–188 , Pl. 29, Fig. 3 , Pl. 33, Fig. 2 , Pl. 15A, Figs 5–7 .

Tyrrhena claparedi: Roule 1896a: 1011 (non Costa in Claparède, 1868).

Tyrrhena atlantica Roule, 1896b: 455–456 , Pl. 21, Figs 9 , 10 , Pl. 24, Fig. 24 , Pl. 25, Figs 28 , 29 ; 1898: 194, 1906: 52–57, Pl. 2, Fig. 10 , Pl. 5, Figs 36–39 , Pl. 8, Figs 72, 73; McIntosh 1901: 227–231.

Leocrates atlantica: McIntosh 1908: 130-134 , Pl. 58, Fig. 17 , Pl. 69, Fig. 17 , Pl. 78, Fig.65.

Leocrates atlanticus: Fauvel 1913: 56–57 ; 1914: 123–124, Pl. 1, Figs 3–4 , Pl. 7, Fig. 23 ; 1923: 235-237, Fig. 88a-h; Pettibone 1970: 222-224, Figs. 20–21 (partim, Fig. 20 , non Fig. 21 ); Amoureux 1972: 72, 1973a: 52, 1973b: 436, 1974a: 109, 1974b: 130; Hartmann-Schröder 1977: 83, 1982: 8; Campoy 1982: 214–215; Sordino 1990: 37; Parapar et al. 2004: 219–221, Figs 77, 78.

Type material. Western Africa. Holotype ( BMNH 1885 : 12: 1: 139), HMS Challenger , Sta. 3, SW off Canary Islands (25°45’ N, 20°14’ W), 2745 m, Feb. 1873 (type lost; E. Sherlock in email, 2018).

Additional material. Western Africa. Five specimens ( MNHN A71), R/V Talisman, combined from three stations by Louis Roule, but two are Dalhousiella carpenteri McIntosh, 1901 . Field data after Vaillant (1888) as follows: 4 specimens, dredge 20 (33°43’ N, 11°22’ W), off Mazagan (El Yadida), Morocco, 1105 m, sand and sponges, 14 Jun. 1883; 1 specimen, dredge 46, between Lanzarote (Canary Islands) and Morocco, 1153 m, yellow sand, 26 Jun. 1883; and 2 specimens, dragage 49, off Lanzarote (Canary Islands), 865–927 m, yellow sand, date not indicated (used for variation as topotypes). One specimen ( MNHN A420), Albert 1 er de Monaco Expeditions, Sta. 198 (38°26’25” N, 28°38’55” W), off South of Fayal, 800 m, sand and mud, 25 Jul. 1888 [19 mm long, 2.3 mm wide]. One specimen ( MOM 180771), Albert 1 er de Monaco Expeditions, Sta. 1116 (31°43’30” N, 10°46’45” W), off Esauria, Morocco, 2165 m, pink sand with globigerinans, 11 Jul. 1901 [19 mm long, 4 mm wide]. Cabo Verde Islands. One specimen ( MOM 180817), Albert 1 er de Monaco Expeditions, Sta. 1203 (15°54’00” N, 22°54’45” W), 6.2 km off SW Boa-Vista Island, 91 m, rocky bottom, 18 Aug. 1901. Açores. 11 specimens ( MOM 180228), Albert 1 er de Monaco Expeditions, Sta. 198 (38°26’25” N, 28°38’55” W), 800 m, sandy mud, 25 Jul. 1888 [16–30 mm long, 3–5 mm wide]. One specimen ( MOM 180401), Albert 1 er de Monaco Expeditions, Sta. 578 (38°26’00” N, 26°30’45” W), 1165 m, sandy mud, 14 Jul. 1895 [26 mm long, 3.5 mm wide]. 11 specimens ( MOM 181144a), Albert 1 er de Monaco Expeditions, Sta. 584 (38°30’30” N, 26°50’15” W), 845 m, rock, 16 Jul. 1895 [13–33 mm long, 2–4 mm wide]. Two specimens ( MOM 181144b), Albert 1 er de Monaco Expeditions, Sta. 584 (38°30’30” N, 26°50’15” W), 845 m, rock, 16 Jul. 1895 [very poor condition]. Two specimens ( MOM 180414), Albert 1 er de Monaco Expeditions, Sta. 587 (36°36’40” N, 27°17’15” W), 793 m, sand, 18 Jul. 1895 [12–22 mm long, 3–4 mm wide]. One specimen ( MOM 180433), Albert 1 er de Monaco Expeditions, Sta. 597 (38°27’00” N, 28°03’25” W), close to Prainha de Pico, 523 m, rock, 23 Jul. 1895 [16 mm long, 2.5 mm wide]. One specimen ( MOM 180445), Albert 1 er de Monaco Expeditions, Sta. 616 (38°46’35” N, 28°17’20” W), close to Rosales or São Jorge Point, 1022 m, gray sandy mud, 1 Aug. 1895 [14 mm long, 2 mm wide]. One specimen ( MOM 180527), Albert 1 er de Monaco Expeditions, Sta. 837 (37°55’00” N, 25°24’15” W), 880 m, rock, 22–24 Jul. 1897 [17 mm long, 3 mm wide]. Two specimens ( MOM 180888), Albert 1 er de Monaco Expeditions, Sta. 1344 (38°45’30” N, 28°07’45” W), 1095 m, volcanic sand, 18 Aug. 1901 [27–32 mm long, 4–5 mm wide]. One specimen ( MOM 180995), Albert 1 er de Monaco Expeditions, Sta. 2214 (39°26’10” N, 31°21’30” W), drifting object with Amphinome pallasii de Quatrefages (probably mislabeled specimen), 1866, 2 Sep. 1904 [19.5 mm long, 2 mm wide]. Celtic Sea. Sixteen specimens ( MNHN CENTOB Thalassa 1973-417), R/V Thalassa, Cruise 1973, Sta. Z417 (48°12’99” N, 09°09’05” W), 865 m, corals, sand to muddy bottom, 21–29 Oct. 1973 [21–28 mm long, 2.5–4.0 mm wide]. Fifteen specimens ( MNHN CENTOB Thalassa 1973-421), R/V Thalassa, Cruise 1973, Sta. Z421 (48°22’05” N, 09°33’05” W), 950 m, calcareous green rocks, sand, 21–29 Oct. 1973 [12–38 mm long, 2–6 mm wide]. Sixteen specimens ( MNHN CENTOB Thalassa 1973-452), R/V Thalassa, Cruise 1973, Sta. Z452 (48°41’05” N, 10°53’00” W to 48°39’00” N, 10°52’02” W), 1420–1470 m, rocks, sand, corals, 21–29 Oct. 1973 [15 complete and one anterior fragment; 12–35 mm long, 2–5 mm wide]. Iberian Seas. One specimen ( MNCN 16.01/121), Banco de Galicia (43°07’ N, 12°14’ W), no further field data [27 mm long, 3.5 mm wide]. One specimen ( MNCN 16.01/10300), Campaña Fauna II, Sta. 171A, E off Islas Sisargas, 89–96 m (strange depth, probably wrong), 27 Jun. 1991 [34 mm long, 3.5 mm wide]. One specimen ( MNCN 16.01/10301), Campaña Fauna II, Sta. 172A, Banco de Galicia (43°07’ N, 12°14’ W), 761–768 m, 28 Jun. 1991 [43 mm long, 7 mm wide]. 29 specimens ( MNCN 16.01/10302), Campaña Fauna II, Sta. 173A, Banco de Galicia (43°07’ N, 12°14’ W), 769– 760 m, 28 Jun. 1991 [25–38 mm long, 2.5–4.0 mm wide]. 12 specimens ( MNCN 16.01/10303), Campaña Fauna IV, Sta. 277 B22, E side of Banco El Fidalgo, Islas Columbretas, Castellón, 25 m, 16 Jul. 1996 [29–36 mm long, 3–4 mm wide]. 10 specimens ( MNCN 16.01/10304), Campaña Fauna II, Sta. 173A, Banco de Galicia (43°07’ N, 12°14’ W), 769– 760 m, 28 Jun. 1991 [16–27 mm long, 2.5–4.0 mm wide]. 18 specimens ( MNCN 16.01/10305), Campaña Fauna II, Sta. 173A, Banco de Galicia (43°07’ N, 12°14’ W), 769– 760 m, 28 Jun. 1991 [29–37 mm long, 3–4 mm wide]. Faroe Islands. One specimen ( NHMD 109402), BIOFAR, SW off Faroe Islands, Sta. 493 (60°49.38’ N, 09°53.27’ W), 800 m, mud, 24 Jul. 1989 [24 mm long, 3 mm wide]. Eight specimens ( NHMD 109404), BIOFAR, SW off Faroe Islands, Sta. 515 (60°41.8’ N, 11°46.5’ W), 700 m, sand, mud, 26 Jul. 1989 [one polynoid without elytrae and posterior end; other specimens 16–31 mm long, 2–4 mm wide]. One specimen ( NHMD 237478), Shamrock Canyon, Sta. 1883/1 (47°48.9’ N, 08°08.87’ W), 1350 m, 19 Apr. 1977, Shackelton, coll. [26 mm long, 4 mm wide].

Description. Largest non-type specimen (MNHN CENTOB Thalassa 1973-417), complete, tapered, slightly damaged, tentacular and dorsal cirri broken, most notochaetal bundles broken, bent laterally and ventrally. Body colorless, stomach darker in some specimens ( Fig. 9A ), 29 mm long, 5 mm wide, 16 chaetigers; right parapodium of chaetiger 8 removed for observing parapodial features. Eyes blackish, posterior prostomial projections blackish; feebly pigmented areas include areas around eyes, projected anteriorly into palpophores and along lateral ciliated bands ( Fig. 10B ), darker in other specimens ( Fig. 9D, E ).

Prostomium as long as wide, wider anteriorly. Lateral antennae longer than prostomium, slightly longer than palps; palpophores slightly longer than palpostyles. Median antenna missing, scar inserted centrally between eyes (other large specimens with median antenna surpassing anterior prostomial margin).

Eyes blackish, anterior ones emarginate, twice larger and slightly more separated than posterior reniform eyes; in lateral view, eyes distinct.

Nuchal organs lobes blackish, slightly longer than wide, pigment spot medially indented, lobes subrectangular, slightly divergent; lateral ciliated areas visible dorsally ( Fig. 9B, E ). Lateral cushions swollen, entire anteriorly, bifid posteriorly, longitudinal striae visible.

Peristomial dorsolateral tubercles low, oval, barely projected, ventrolateral tubercles indistinct. Pharynx evert- ed, anterior margin ciliated, lateral vesicles not swollen, left one slightly more projected; basal ring smooth. Jaws brownish, upper jaw double, lower jaw transverse with exposed region semicircular, almost transparent ( Figs 5 A–C, 9C, F).

Longest tentacular cirri without tips, reaching chaetiger 6. Dorsal cirri broken, shorter than body width. Chaetigers 1–3 without notochaetae, notochaetae present along chaetigers 4–16, mostly broken (abundant, about 50 per bundle in another large specimen), subdistally denticulate, denticles fine. Notacicular lobes triangular, tapered ( Fig. 9G ), or blunt ( Fig. 10G ); neuracicular lobes as long as wide, blunt. Neurochaetae brownish, handle and basal portion of blades pigmented, about 50 per bundle, blades denticulate, decreasing in size ventrally, 3–20 times longer than wide ( Fig. 10H, I ), tips of longest blades difficult to be seen, guards approaching subdistal tooth.

Posterior region tapered; prepygidial segment with dorsal cirri 3 times longer than ventral ones; pygidium with anus terminal, anal cirri missing (other large specimens with broken cirri, reaching chaetiger 13).

Gonads visible inside parapodia; oocytes not seen.

Variation. Five presumptive topotype specimens (MNHN A71) with body grayish, twisted, most cirri missing, many chaetae broken, eyes and nuchal organs brownish to blackish ( Fig. 10A, E ). Body obconic, 20–32 mm long, 3–4 mm wide, 16 chaetigers. Lateral antennae shorter than prostomium or palps, broken in several specimens; palpophores slightly longer than palpostyles, bent ventrally ( Fig 10B, F ). Median antenna short, not reaching prosto- mial anterior margin, inserted between eyes. Nuchal organs lobes partially covered by anterior margin of tentacular belt, parallel, blackish; lateral ciliated bands wide, visible dorsally. Pharynx exposed; jaws with exposed portions hyaline, transverse to pharynx; upper jaw double, separated, lower jaw double, fused as a transverse plate ( Fig. 10C ). Dorsal cirri broken, shorter than body width (excluding parapodia). Notochaetae present along chaetigers 4–16; notacicular and neuracicular lobes conical, three times longer than wide, tapered ( Fig. 10D, G ). Notochaetae about 30 per bundle, subdistally denticulate, denticles fine. Neurochaetae golden, 30–40 per bundle, blades bidentate, 8–18 times longer than wide, guards approaching subdistal tooth. Posterior region tapered into a blunt cone; prepygidial segment without cirri, pygidium with anus terminal, anal cirri missing. Gonads with spermatids; ovaries seen in parapodia by transparency, oocytes about 100 µm in diameter ( Fig. 10G ).

Remarks. The holotype of Dalhousia atlantica McIntosh, 1885 is lost (E. Sherlock, 2018 in email). Pettibone (1970) redescribed and illustrated the type specimen, although she included another species from Indonesia, D. indica ( Horst, 1921) n. comb., as a junior synonym. As indicated in the key above and in the corresponding redescription, they are different. The above description, as well as the variation, are based upon topotype and non-type specimens.

Distribution. Originally described from off the Canary Islands, in deep water sediments (2745 m), it can be found from the Faroe Islands to Western Africa, in 760–1470 m depth. There is a surface record, in a drifting object by Fauvel (1914); the specimen (MOM 180995) matches the species and it is herein regarded as a mislabeled specimen. Other records for shallow water in Western Africa by Fauvel (1950: 349, 1953a: 18) cannot be confirmed because his specimens were not available; additional records correspond with Paralamprophaea greeffiana ( Augener, 1918) n. comb. (see below).

Figures

FIGURE 2. A. Leocrates claparedii (Costa in Claparède, 1868), non-type specimens (USNM 5131), anterior end, dorsal view, pharynx everted. B. Another specimen, anterior end, dorsal view, pharynx fully everted. C. Same, pharynx and jaws, left lateral view (1: Pharynx ring I, 2: Pharynx ring II, AM: anterior margin, DT: dorsolateral tubercle, LJ: lower jaw, LV: lateral vesicle, Pe: peristomium, TB: tentacular belt, UJ: upper jaw). D. Lamprophaea poupini n. sp., holotype (UF 858), anterior end, right lateral view, after SAS (1–8: tentacular cirri, Ch: chaetiger, LA: lateral antenna, NO: nuchal organ lobe, Pa: palp, TB: tentacular belt). Scale bars: A, C: 0.5 mm, B: 0.7 mm, D: 0.3 mm.

FIGURE 3. Lamprophaea longicirrata (Treadwell, 1902), new combination, non-type specimens, Florida (ECOSUR 3075), prostomia, dorsal view. A. Smallest specimen, 13x2 mm. B. Medium-sized specimen, 32x3.5 mm. C. Large specimen, pharynx slightly exposed, 32x4 mm. D. Small specimen, pharynx exposed, 20x3 mm. Scale bars: A: 0.25 mm, B–C: 0.4 mm, D: 0.30 mm.

FIGURE 4. Dalhousia atlantica McIntosh, 1885, reinstated, non-type specimens (ECOSUR 2185), North Sea.A. Anterior end, dorsal view, pharynx partially exposed. B. Anterior end, dorsal view, pharynx fully exposed. C. Largest specimen, anterior end, dorsal view. D. Pharynx, frontal view, upper and lower jaws project inwardly (*: left lateral vesicle). E. Pharynx section, frontal view, showing upper double jaw. F. Same, frontal view, showing lower transverse jaw. Scale bars: A: 0.4 mm, B, C: 0.5 mm, D: 0.9 mm, E: 0.3 mm, F: 0.5 mm.

FIGURE 5. A. Dalhousia atlantica McIntosh, 1885, reinstated, non-type specimen (MNCN 10304), Banco de Galicia, pharynx dissected to show upper (left) and lower (right) jaws. B. Same, upper double jaw, most tissue removed. C. Same, lower transverse jaw, posterior view, note its complete longitudinal fusion. D. Paralamprophaea greeffiana (Augener, 1918) n. comb., non-type specimen (MNHN 372), upper jaw in posterior and lateral views (*: ligament). E. Same, lower jaw in anterior, lateral and posterior views. Scale bars: A: 0.24 mm, B: 0.22 mm, C: 0.27 mm, D: 0.18 mm, E: 0.14 mm.

FIGURE 9. Dalhousia atlantica McIntosh, 1885, non-type specimens (MNHN CENTOB Thalassa 1973-417). A. Anterior region, dorsal view. B. Same, anterior end, close-up of anterior end. C. Same, pharynx, oblique frontal view. D. Another specimen, anterior region, dorsal view. E. Same, anterior end, dorsal view. F. Same, pharynx, oblique frontal view. G. Smallest specimen, chaetiger 8, right parapodium, anterior view, MGS (inset: notacicular lobe). H. Same, lower neurochaetal blade. I. Same, upper neurochaetal blade. J. Largest specimen, chaetiger 8, right parapodium, anterior view, MGS. Scale bars: A: 2 mm, B: 0.2 mm, C: 0.8 mm, D: 2.5 mm, E: 1.3 mm, F: 1 mm, G, J: 0.5 mm, H: 30 µm, I: 70 µm.

FIGURE 10. Dalhousia atlantica McIntosh, 1885, non-type specimens (MNHN A71). A. Anterior region, dorsal view. B. Same, anterior end, dorsal view. C. Same, pharynx, frontal view, after MGS. D. Smallest specimen (20 mm long), chaetiger 8, left parapodium, anterior view, SAS. E. Another specimen, anterior region, dorsal view. F.Anterior end, dorsal view. G. Largest specimen (32 mm long), chaetiger 8, left parapodium, anterior view, SAS. Scale bars: A: 2 mm, B, D: 0.7 mm, C: 1 mm, E, G: 0.9 mm, F: 0.5 mm.

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 20. Lamprophaea paulayi n. sp., holotype (UF 3887). A. Dorsal view. B. Anterior region, dorsal view. C. Anterior end, dorsal view, MGS. D. Chaetiger 9, right parapodium, anterior view, MGS. E. Same, superior (200 µm long), and inferior neurochaetal blades (120 µm long). Scale bars: A: 2.3 mm, B: 1.8 mm, C: 0.7 mm, D: 0.4 mm.

FIGURE 21. Lamprophaea paulayi n. sp., paratype (UF 4223). A. Anterior region, dorsal view. B. Anterior end, dorsal view, MGS. C. Chaetiger 8, left parapodium, anterior view (insets: inferior and superior neurochaetal blades). Scale bars: A: 0.5 mm, B, C: 0.3 mm.

FIGURE 23. Lamprophaea pleijeli n. sp., holotype (UF 659). A. Anterior region, dorsal view, depressed by glass slide fragment. B. Anterior end, dorsal view. C. Pharynx, everted, frontal view, MGS. D. Chaetiger 8, left parapodium, anterior view, MGS. E. Same, chaetae (insets: longer and shorter neurochaetal blades). F. Posterior region, ventral view. Scale bars:A: 1.5 mm, B, C, E: 0.5 mm, D: 0.4 mm, F: 2 mm.

FIGURE 24. Lamprophaea poupini n. sp., holotype (UF 858). A. Anterior region, dorsal view. B. Anterior end, dorsal view, SAS. C. Pharynx, frontal view, SAS. D. Chaetiger 9, right parapodium, anterior view. E. Upper and lower neurochaetal blades. Scale bars: A: 1.1 mm, B, D: 0.8 mm, C: 0.9 mm, E: 130 µm.

FIGURE 28. Leocrates claparedii (Costa in Claparède, 1868), non-type specimens (USNM 5131). A. Shortest specimen, anterior region, dorsal view, MGS. B. Same, anterior end, dorsal view. C. Chaetiger 8, right parapodium, anterior view (inset: lower neurochaetal blade). D. Longest specimen, anterior region, dorsal view, MGS (*: left lateral vesicle). E. Same, anterior end, dorsal view (*: left lateral vesicle). F. Chaetiger 8 or 9, right parapodium, anterior view (insets: notacicular lobe, longer and shorter neurochaetal blades). Scale bars: A, D: 1.6 mm, B: 0.7 mm, C, F: 0.5 mm, E: 0.8 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 36. Leocrates reishi n. sp., holotype (LACM 10883). A. Dorsal view, middle depression and shine due to glass slide. B. Anterior end, dorsal view. C. Pharynx, frontal view. D) Chaetiger 7, right parapodium, anterior view (insets: notacicular lobe, lower and upper neurochaetal blades). Scale bars: A: 1.8 mm, B: 0.7 mm, C: 0.6 mm, D: 0.4 mm.

FIGURE 37. Leocrates reishi n. sp. A. Paratype (LACM 10884), anterior region, dorsal view. B. Same, anterior end, dorsal view, MGS. C. Same, chaetiger 12, right parapodium, anterior view, MGS. D. Additional specimen (LACM 10142), anterior region, dorsal view. E. Same, anterior end, dorsal view, MGS. F. Same, chaetiger 11, right parapodium, anterior view. Scale bars: A: 0.8 mm, B, F: 0.4 mm, C: 0.3 mm, D: 1.4 mm, E: 0.5 mm.

FIGURE 38. Leocrates rizzoae n. sp., holotype (USNM 37642). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Anterior end, ventral view. D. Chaetiger 10, right parapodium, anterior view, MGS. Scale bars: A: 0.7 mm, B: 0.5 mm, C: 0.6 mm, D: 0.2 mm.

FIGURE 39. Leocrates rizzoae n. sp., paratype (USNM 37641). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Chaetiger 10, right parapodium, anterior view, MGS (insets: upper and lower neurochaetal blades, notacicular lobe). Scale bars: A: 0.8 mm, B, C: 0.3 mm.