Bathymoorea lucasi, Bonifácio & Menot, 2019

Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), Zoological Journal of the Linnean Society 185, pp. 555-635 : 573-577

BATHYMOOREA LUCASI SP. NOV.

( FIG. 4A–P; TABLES 1, 2)

Type material: Holotype, MNHN-IA-TYPE 1821 ( IFR601-1 ), complete, length 9.95 mm, width 1.35 mm, 27 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W, end 18°48.13′N, 128°18.20′W, 4933–4964 m depth . Paratype 1, MNHN-IA-TYPE 1822 ( IFR600 ), complete, length 11.30 mm, width 1.35 mm, 29 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W , end 18°48.13′N, 128°18.20′W, 4933–4964 m depth. Paratype 2,MNHN-IA-TYPE 1823 ( IFR601-7 ), complete, in very poor condition but pharynx dissected in good condition, length 8.64 mm, width 1.24 mm, 26 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W , end 18°48.13′N, 128°18.20′W, 4933–4964 m depth. Paratype 3, NHMUK 2018.25349 ( IFR601-6 ) for SEM, incomplete, 11 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion- Clipperton Fracture Zone , APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W, end 18°48.13′N, 128°18.20′W, 4933–4964 m depth . Paratype 4, MNHN- IA-TYPE 1844 ( IFR601-2 ), complete, length 7.66 mm, width 1.08 mm, 25 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion- Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W , end 18°48.13′N, 128°18.20′W, 4933–4964 m depth.

Additional material: Specimen 1, MNHN-IA-PNT 77 ( IFR601-3 ), complete, length 8.05 mm, width 0.96 mm, 25 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W, end 18°48.13′N, 128° 18.20′W, 4933–4964 m depth . Specimen 2, MNHN-IA-PNT 78 ( IFR601- 4 ), incomplete, length 5.67 mm, width 0.96 mm, 16 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W, end 18°48.13′N, 128°18.20′W, 4933– 4964 m depth . Specimen 3, P.B. ’s collection ( IFR601- 5 ), incomplete, length 4.42 mm, width 1.03 mm, ten segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion-Clipperton Fracture Zone, APEI#3 nodules, station 189, collected 20–21 April 2015, ROV Kiel 6000, biobox, start 18°47.80′N, 128°18.53′W, end 18°48.13′N, 128°18.20′W, 4933– 4964 m depth . Specimen 4, P.B. ’s collection ( IFR667 ), incomplete, 15 segments (including tentacular segment), Equatorial Eastern Pacific Ocean , Clarion- Clipperton Fracture Zone, APEI#3 nodules, station 200, collected 22–23 April 2015, ROV Kiel 6000, biobox, start 18°49.22′N, 128°25.55′W, end 18°49.60′N, 128°25.48′W, 4698– 4696 m depth .

Description (based on holotype and paratypes): Holotype complete, 9.95 mm long and 1.35 mm wide for 27 segments (including tentacular segment), dorsoventrally flattened, not tapering posteriorly; live specimen coloration pale yellow body and prostomium; ethanol-preserved specimen with pale yellow body ( Fig. 4A), dark dots present on middle and posterior margin of prostomium, dark spots sparsely covering mid-ventrum of body and dorsal surface of notopodia, styles of lateral antennae and ventral cirri brownish medially to distally, nephridial papillae brownish.

Prostomium bilobed, wider than long, with large pair of whitish ocular areas ( Fig. 4H, A). Median and lateral antennae present; ceratophore of median antenna large, bulbous, inserted near anterior margin, style missing; lateral antennae inserted on anterior extension of prostomium subterminally to ceratophore of median antenna, styles smooth, tapering, short (about one-quarter length of palps). Palps smooth, tapering distally to thin tips, short (reaching to segment 4; Fig. 4H). Facial tubercle present, bulbous.

Tentacular segment with short lobe, inserted laterally and slightly ventral to prostomium; with acicula not penetrating epidermis, with chaetae; tentaculophores large, cylindrical, equal sized ( Fig. 4H); tentacular styles missing. Mouth lips strongly developed, protruding when pharynx not everted. Pharynx not everted in holotype; dissected in paratype (MNHN-IA-TYPE 1823), with nine pairs of subtriangular, equal-sized distal papillae, two pairs of jaws, each with main fang, margin smooth ( Fig. 4I). Second segment with elytrophores, subbiramous parapodia, chaetae and ventral cirri.

Thirteen pairs of large, bulbous elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23 and 26 (all elytra missing); elytrophores large, bulbous.

Cirrigerous segments with distinct, bulbous dorsal cirrophores ( Fig. 4H, J, K), inserted basally on notopodia; styles (mostly missing) sparsely papillated, tapering, very short on segment 2 (shorter than neuroacicular tip), long on segment 6 (longer than neuroacicula tip); dorsal tubercle lamelliform, short (as long as dorsal cirrophore; Fig. 4H, J, K).

Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (longer than tip of neuroacicular lobe); in subsequent segments inserted medially and basally on neuropodia of posterior segments ( Fig. 4J, L), style short (shorter than tip of neuroacicular lobe).

Parapodia subbiramous, notopodia shorter than neuropodia ( Fig. 4J). Notopodia subtriangular, tapering into long acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae moderate in number (≥ 20 observed), short or long, stout, distally curved, with distinct, well-developed spinous rows on convex side, with pointed tips ( Fig. 4B, C, M, N); notochaetae stouter than neurochaetae. Neurochaetae very numerous (~60 observed), very long, distally flattened with faint spinous rows, with pointed tip ( Fig. 4D–G, O, P); in lower neurochaetae, spinous rows distally clustering into two groups.

Nephridial papillae present from segment 5 (in paratype MNHN-IA-TYPE 1844, from segment 6) to end of body, small, bulbous ( Fig. 4L). Pygidium small, rounded, not enclosed by last segment ( Fig. 4A); with terminal anus. Anal cirri lost, scars not seen.

Morphological variation: Specimens with 25, 26, 27 and 29 segments were found. The form of the prostomial appendages, shape of parapodia and form of chaetae were similar to those of the types. However, specimens with 25 and 29 segments possessed 12 and 13 pairs of elytrophores, respectively. Differences are probably linked to size or growth/development stages of the animals, because DNA confirmed that all specimens belonged to the same species. Furthermore, variation in the first occurrence of nephridial papillae is also linked to size; in animals with 25 segments the nephridial papilla started from segment 5 or 6, whereas in animals with> 25 segments the nephridial papilla always started from segment 5. Worms also differed in having short and long dorsal cirri in the anterior part of the body, but in the posterior body the observed dorsal cirri were always long. Loss and regeneration could explain the very short dorsal cirri observed in the anterior body.

Remarks: Bathymoorea has contained a single species, Bathymoorea renotubulata ( Moore, 1910) since its erection by Pettibone (1967). The specimens found in the CCFZ are similar to Bathymoorea renotubulata as follows: short body, large ocular areas, similar prostomial shape and form of distally flattened neurochaetae with faint spinous rows, which appear bidentate in lateral view as opposed to unidentate in Bathymoorea lucasi sp. nov. Bathymoorea lucasi sp. nov. differs from Bathymoorea renotubulata in having fewer segments (≤ 29), very short lateral antennae, short palps, presence of acicula and notochaetae on the tentacular segment, short neuropodial lobes and very reduced (bulbous) nephridial papillae. In comparison, Bathymoorea renotubulata has 33 segments, long antennae, long palps, achaetous tentaculophores, elongate neuropodial lobes and elongate nephridial papillae.With regard to chaetae, notochaetae are robust with well developed rows of spines in Bathymoorea lucasi sp. nov. instead of the delicate and fine spines in Bathymoorea renotubulata .

Etymology: This species is dedicated to Lucas Lisboa, cousin of P.B., for his friendship.

Genetic data: DNA sequencing for this species was successful for COI, 16S and 18S, respectively sharing at least 98.6, 99.3 and 100% of genetic material between the specimens. The average K2P distance for intraspecific variation was 0.8% for COI and 0.2% for 16S.

Distribution: Based on the material examined (nine specimens), this species has a restricted distribution within the Clarion-Clipperton Fracture Zone, being sampled at two stations in APEI#3 nodules area (type locality).

Ecological notes: During the sampling at station 189, 11 Hexactinellida sponges were sampled together with a few ophiuroids and alcyonaceans, all conditioned in the biobox of the ROV.At station 200, six Hexactinellida sponges were sampled together with anthipatharians, crinoids, hydrozoans, ophiuroids and tunicates. The specimens of the new species Bathymoorea lucasi sp. nov. were found by sieving water from the biobox, which indicates a possible commensalism with the sponges.

MACELLICEPHALINAE HARTMANN- SCHRÖDER, 1971

Macellicephalinae Hartmann-Schröder, 1971: 75 . – Hartmann-Schröder, 1974: 75. – Pettibone, 1976: 6. – Uschakov, 1982: 108 (translated version). – Pettibone, 1985d: 129. – Pettibone, 1994: 609. – Jirkov, 2001: 127. – Barnich & Fiege, 2003: 90.

Bathyedithinae Pettibone, 1976: 53 .

Bathymacellinae Pettibone, 1976: 58 .

Branchinotogluminae Pettibone, 1985a: 447 . – Pettibone, 1993a: 679.

Branchiplicatinae Pettibone, 1985b: 150 .

Branchipolynoinae Pettibone, 1984a: 227 .

Lepidonotopodinae Pettibone, 1983: 392 . – Pettibone, 1984b: 850.

Macellicephaloidinae Pettibone, 1976: 42 .

Macelloidinae Pettibone, 1976: 48 .

Polaruschakovinae Pettibone, 1976: 55 . – Hartmann- Schröder, 1996: 72. – Barnich & Fiege, 2003: 92.

Vampiropolynoinae Marcus & Hourdez, 2002: 342 .

Type genus: Macellicephala McIntosh, 1885 .

Diagnosis: Median antenna absent ( Bathycanadia Levenstein, 1981 , Bathyedithia Pettibone, 1976 , Bathymariana Levenstein, 1978 , Bathymiranda Levenstein, 1981 , Diplaconotum Loshamn, 1981 , Hodor gen. nov., Nu gen. nov. and Polaruschakov Pettibone, 1976 ) or present ( Abyssarya gen. nov., Austropolaria Neal, Barnich, Wiklund & Glover, 2012 , Bathybahamas Pettibone, 1985d , Bathycatalina Pettibone, 1976 , Bathyeliasona Pettibone, 1976 , Bathyfauvelia Pettibone, 1976 , Bathykermadeca Pettibone, 1976 , Bathykurila Pettibone, 1976 , Bathylevensteina Pettibone, 1976 , Bathymacella Pettibone, 1976 , Bathypolaria Levenstein, 1981 , Bathyvitiazia Pettibone, 1976 , Bathytasmania Levenstein, 1982a , Branchinotogluma Pettibone, 1985 a , Branchiplicatus Pettibone, 1985 b , Branchipolynoe Pettibone, 1984a , Bruunilla Hartman, 1971 , Gesiella Pettibone, 1976 , Lepidonotopodium Pettibone, 1983 , Levensteiniella Pettibone, 1985c , Macellicephala McIntosh, 1885 , Macellicephaloides Uschakov, 1955 , Macelloides Uschakov, 1957 , Natopolynoe Pettibone, 1985c , Peinaleopolynoe Desbruyères & Laubier, 1988 , Pelagomacellicephala Pettibone, 1985d , Thermopolynoe Miura, 1994 , Vampiropolynoe Marcus & Hourdez, 2002 and Yodanoe gen. nov.); and lateral antennae absent.

Remarks: Pettibone (1976) has reviewed numerous species directly or indirectly related to Macellicephalinae and erected four new subfamilies (i.e. Bathyedithinae , Macellicephaloidinae , Macelloidinae and Polaruschakovinae ). Uschakov (1982), however, did not agree with this rearrangement. Based on molecular ( Fig. 2) and morphological phylogenetic analyses ( Fig. 3), our data support previous studies (Hartmann- Schröder, 1971; Uschakov, 1982), which suggest grouping polynoids with or without a median antenna and without lateral antennae into a single subfamily (see Discussion for more details). Consequently, the above subfamilies, characterized by the synapomorphic absence of lateral antennae, are here synonymized with Macellicephalinae sensu Hartmann-Schröder, 1971 .