Laubieriopsis brevis ( Hartman, 1965 )

Salazar-Vallejo, Sergio I., Zhadan, Anna E. & Rizzo, Alexandra E., 2019, Revision of Fauveliopsidae Hartman, 1971 (Annelida, Sedentaria), Zootaxa 4637 (1), pp. 1-67 : 44-48

Laubieriopsis brevis ( Hartman, 1965)

Figures 26–28

Brada brevis Hartman, 1965: 172–173 .

Fauveliopsis brevis: Hartman & Fauchald 1971: 115–116 , Pl. 16 (n. comb.); Laubier 1972: 699–700, Amoureux 1982: 194. Laubieriopsis brevis: Petersen 2000: 510 (n. comb., key); Martínez & Adarraga 2012: 6–10, Fig. 2 .

TL: S off Providence, Rhode Island, 2000 m. D: Western Atlantic, from the United States to off NE South Ameri- ca.

Type material: Northwestern Atlantic Ocean. Holotype (LACM 527) and three paratypes (LACM 528), SSW off Nantucket, R/V Atlantis, Sta. G1 (39°42’ N, 70°39’ W), 2000 m, anchor dredge, 24 May 1961, H. Sanders, coll. (holotype 5.3 mm long, 0.3 mm wide, GP right side between chaetigers 6 and 7, anal plate with two cirriform short papillae; paratypes 2.2–4.0 mm long, 0.2–0.4 mm wide, 16 chaetigers; GP on both sides, posterior margin of chaetiger 6, only in largest paratype; anus without large papillae).

Additional material. Northwestern Atlantic Ocean. 19 specimens ( LACM 7548 ), R/ V Atlantis, Sta. 62 (39°26’ N, 70°33’ W), 2496 m, anchor dredge, 21 Aug. 1961, H. Sanders, coll. (4 for SEM; body 3.0–8.0 mm long, 0.2–0.5 mm wide, all with 16 chaetigers; GP paired, posterior margin of chaetiger 6; oocytes present in specimens 6.7 mm long; anus with 2–3 digitate papillae, two dorsal and one ventral, often bent and difficult to detect). Four specimens ( LACM 7552), slightly macerated, R/V Atlantis, Sta. 64 (38°46’ N, 70°06’ W), 2886 m, anchor dredge, 21 Aug. 1964, H. Sanders, coll. (7.1–8.1 mm long, 0.4–0.6 mm wide, 16 chaetigers; GP not visible, anal papillae distinct in two specimens; fragments of delicate, fibrous tubes; thickest specimen used for illustration by Hartman & Fauchald 1971, Pl 16). 21 specimens ( LACM 7546), R/V Atlantis, Sta. 66 (38°46.7’ N, 70°08.8’ W), 2807 m, anchor dredge, 21 Aug. 1964, H. Sanders, coll. (1.7–8.5 mm long, 0.20–0.6 mm wide, 16 chaetigers, except the smallest specimen with 12 chaetigers; GP paired, posterior margin of chaetiger 6, visible only in large specimens; oocytes in specimens 7.8 mm long; anus without large papillae). 31 specimens ( LACM 7545), R/V Atlantis, Sta. 73 (39°46.5’ N, 70°43.3’ W), 1470– 1330 m, anchor dredge, 25 Aug. 1964, H. Sanders, coll. (3.0– 8.4 mm long, 0.2–0.5 mm wide, 16 chaetigers; GP on posterior margin of chaetiger 6; pygidium invaginated; two small specimens with rugose integument, one with smooth integument through 5 chaetigers, then rugose, probably Fauveliopsis in regeneration). One specimen ( LACM 7561), obliquely cut in two portions, right genital papilla broken, R/V Chain, Sta. 83 (34°46.5’ N, 66°30’ W), 5000 m, anchor dredge, 3 Jul. 1965, H. Sanders, coll. (4.8 mm long, 0.3 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6; anal papillae not seen). Seven specimens (in two separate vials, LACM 7553, 7555), R/V Atlantis, Sta. 126 (39°37.0’ N, 66°47.0’ W to 39°37.5’ N, 66º44.0’ W), 3806 m, anchor dredge, 24 Aug. 1966, H. Sanders, coll. (one specimen for SEM; others 4.9–7.3 mm long, 0.2–0.4 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6; anal papillae visible in both specimens). Three specimens ( LACM 7559), off N Surinam, R/V Chain, Sta. 34, Dredge 34 (08°45.5’ N, 53°44’ W to 08°46.5’ N, 53°48’ W), 1500 m, anchor dredge, 25 Apr. 1963, H. Sanders, coll. (2.6–5.9 mm long, 0.2–0.5 mm wide, 16 chaetigers; GP paired, posterior margin of chaetiger 6; oocytes in specimen 3.1 mm long; pygidium partly invaginated, anal papillae digitate, difficult to be observed; chaetal lobes well-defined). Nine specimens ( LACM 0000), R/V Chain, Sta. 76 (39°38.3’ N, 67°57.8’ W), 2862 m, 29 Jun. 1965, H. Sanders, coll. (5.9–9.1 mm long, 0.2–0.5 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6, oocytes in chaetigers 5–8). Two specimens ( LACM 7560), R/V Chain, Sta. 100 (33°56.8’ N, 65°47.0’ W), 4892– 4743 m, 2 May 1965, H. Sanders, coll. (2.3–4.8 mm long, 0.2–0.3 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6, oocytes in larger specimen, in chaetigers 5–7; smaller with last chaetiger barely developed). 17 specimens ( LACM 7556, 7563), R/V Chain, Sta. 103 (39°43.6’ N, 70°37.4’ W), 2022 m, anchor dredge, 4 May 1966, H. Sanders, coll. (four specimens for SEM; others 3.0– 7.1 mm long, 0.3–0.7 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6, oocytes in specimens 5.0 mm long; pygidium invaginated, anal papillae not visible in most specimens, only visible in smaller specimens; fragments of delicate, fibrous tube). Five specimens ( LACM 7558), R/V Chain, Sta. 105 (39°56.6’ N, 71°03.6’ W), 530 m, 5 May 1965, H. Sanders, coll. (5.0– 7.4 mm long, 0.4–0.7 mm wide, 16 chaetigers; GP on pos- terior margin of chaetiger 6, oocytes in chaetigers 5–8, about 100 µm). Two specimens ( USNM 1558268), ESE off Nantucket, R/V Albatross, Sta. 2084 (40°16’50” N, 67°05’15” W), 2322 m, blue mud, sand, 5 Sep. 1883 (7.5–8.0 mm long, 0.4–0.6 mm wide, 16 chaetigers; oocytes 100 µm, in chaetigers 5–7). North central Atlantic. One specimen ( SIORAS AK 488), Central North Atlantic R/V Akademik Mstislav Keldysh, cruise 4, Sta. 488 (58°21’07” N, 31°39’30” W), 1595 m, 7 Sep. 1982 (small, partially dried specimen of the thick form; 5.5 mm long, 0.5 mm wide, chaetigers difficult to count because chaetae are broken and salt crystals are adsorbed to body wall; this specimen might be conspecific with L. brevis Hartman, 1965 ). Northeastern Atlantic Ocean. 20 specimens ( MNHN 901b), Abyplaine, Sta. 12 (44°39’ N, 17°48’ W to 44°41’ N, 18°01’ W), 4990 m, 20–21 Jul. 1981. 92 specimens ( MNHN 901a), Abyplaine, 4220–5500 m, May–June 1981 [despite the differences in size (2.2–5.8 mm long, 0.15–0.50 mm wide), they all have 16 chaetigers. A few specimens with the head completely exposed; mature females have few oocytes, 8–10 per female, and restricted to a few anterior chaetigers (5–7); females are apparently mature when reaching a length of 4 mm. Paired genital papillae are placed just before chaetal lobes of chaetiger 7 in both sexes. Western Mediterranean. Two specimens ( LACM 11293), R/V Jean-Charcot, Sta. DS 09 (38°27.0’ N, 04°08.0’ W to 38°28.8’ N, 04°09.0’ W), 2447 m, epibenthic sled, 31 May 1970, H. Sanders, coll. (one for SEM; body 3.5–4.2 mm long, 0.4–0.5 mm wide, 16 chaetigers; GP paired, on posterior margin of chaetiger 6; anal papillae two, dorsal, exposed despite markedly contracted bodies). One specimen ( LACM 7511), R/V Vema, Sta. 14-55 (39°09’ N, 06°27’ E), 2845–2847 m, bottom trawl, coarse sand, 4 Apr. 1958 (twisted, partly dehydrated, some chaetae broken, 16 chaetigers). South Atlantic. Argentina. 17 specimens ( LACM 7512), E off Trelew, R/V Vema, Sta. 17-81 (44°33’ S, 49°19’ W), 5334– 5330 m, standard bottom trawl, small rounded pebbles, 27 May 1961 (body wall thick, some with cuticle detached; body 5.5–7.0 mm long, 0.4–0.8 mm wide, 16 chaetigers; GP paired, posterior margin of chaetiger 6, only in some specimens, before chaetal lobes of chaetiger 7; oocytes in chaetigers 5–8, each about 100 µm; many chaetae reddish-brown). One specimen ( SIORAS AK 862), R/V Akademik Kurchatov, cruise XI, Sta. 862 (54°35.4’ S, 26°12.0’ W), 5078 m, 25 Nov. 1971 (body of the thick form; 11 mm long, 1 mm wide, 16 chaetigers; grapes-like egg mass between chaetal lobes 6 and 7; each very small). One specimen ( SIORAS AK 875), R/V Akademik Kurchatov, cruise XI, Sta. 875 (55°49.6’ S, 26°39.0’ W), 4720 m, 30 Nov. 1971 (body of the thick form; 11.5 mm long, 0.9 mm wide, 16 chaetigers). One specimen ( SIORAS AK 896), R/V Akademik Kurchatov, cruise XI, Sta. 896 (56°52.0’ S, 24°59.0’ W), 5651 m, 5 Dec. 1971 (two other specimens in the same container; one Flabelligella sp, with the anterior end exposed and a Pherusa sp very damaged; body twisted, of the thick style, 7 mm long, 0.6 mm wide, 16 chaetigers, immature). Nine specimens ( SIORAS AK 898), R/V Akademik Kurchatov, cruise XI, Sta. 898 (56°47.5’ S, 24°56.2’ W), 6150 m, 5 Dec. 1971 (body with iridescent integument; two morphs: one thinner, more transparent and with the cuticle more granulose due to transverse, regular discontinuities, and posterior region progressively widened and terminates in a blunt cone; the other thicker, darker, with the cuticle smoother, and posterior region progressively widened but terminates abruptly in two lateral large lappets; they are 14.0– 14.5 mm long, 0.8–1.0 mm wide, 16 chaetigers). One specimen ( SIORAS AK 908), R/V Akademik Kurchatov, cruise XI, Sta. 908 (60°13.5’ S, 44°10.6’ W), 5474 m, 10 Dec. 1971 (body twisted, thick, 8 mm long, 0.5 mm wide, 16 chaetigers, immature). Brazil. 2 complete specimens ( UERJ 1632), Sta. Hab9 Canac7 (21°47’22.164” S, 40°02’01.506”” W), R2 (0–2 cm), Box corer, 780 m, 6 Feb. 2009 (0.6–0.7 mm long, 0.2–0.3 mm wide, one with 13 chaetigers and another with 14, juveniles, one with pygidium invaginated). 2 complete specimens ( UERJ 3373), Sta. Hab6 Canac6 (21°49’59.010” S, 40°06’20.800” W), R2 (2–5 cm), Box corer, 469 m, 28 Jun. 2008 (both 1.0 mm long, 0.3 mm wide, 15 chaetigers, juveniles). 2 complete specimens ( UERJ 5998), R/V Seward Johnson, Sta. Amb8 (19°03’45.82” S, 37°47’28.26” W), G8R1+R3 (0–10 cm), Box corer, 1928 m, 29 Jan. 2012 (4.0 mm long, 0,25 mm wide, 16 chaetigers; 3.3 mm long, 0.3 mm wide, 16 chaetigers). 2 complete specimens ( UERJ 6033), R/V Seward Johnson, Sta. Amb4 (20°35’50.48” S, 38°27’07.64” W), E9R1+R2 (0–10 cm), Box corer, 2494 m, 22 Dec. 2011 (4.8 mm long, 0.4 mm wide, 16 chaetigers, everted prostomium; 1.5 mm long, 0.25 mm wide, 14 chaetigers). 1 complete specimen ( UERJ 6052), R/V Seward Johnson, Sta. Amb11 (20°46’17.79” S, 38°17’16.01” W), F10R3 (0–10 cm), Box corer, 3002 m, 13 Jun. 2013 (3.0 mm long, 0.3 mm wide, 16 chaetigers). 1 specimen complete ( UERJ 6018), R/V Seward Johnson, Sta. Amb12 (19°03’39.78” S, 37°47’39.35” W), G8R2 (0–10 cm), Box corer, 1867 m, 30 Jun. 2013 (1.0 mm long, 0.2 mm wide, 12 chaetigers, juvenile). 1 specimen complete ( UERJ 6068), R/V Seward Johnson, Sta. Amb5 (21°04’09.61” S, 40°13’07.38” W), A5R3 (0–10 cm), Box corer, 410 m, 30 Dec. 2011 (1.0 mm long, 0.2 mm wide, 16 chaetigers).

Diagnosis. Laubieriopsis with 16 chaetigers. First 4 anterior parapodia with two aciculars and two capillaries per bundle ( Figs 26A, B, D , 27 A–C, 28A, B). Median and posterior parapodia with one acicular and one capillary per ramus ( Figs 27D, E , 28F ). Interramal papillae subglobular ( Figs 27D, E , 28E, F ). Genital papillae paired, on both sides of posterior margin of chaetiger 6 ( Figs 26F , inset, 27D, E). Last chaetiger with longer aciculars, often with a thin capillary, reaching beyond pygidium border ( Figs 26C, E , 27E , 28D ). Pygidium with three digitate, anal papillae, two dorsal, one ventral ( Figs 26C , 27E ). Pharynx cylindrical, short ( Fig. 28C ).

Remarks. Laubieriopsis brevis resembles L. hartmanae because both have 16 chaetigers and their genital papillae (GP) is over chaetiger 6–7. Their main difference is in the type of aciculars along anterior chaetigers, as indicated in the key above. In L. brevis aciculars have tips bidentate, whereas in L. hartmanae they are tapered. Other subtle but consistent differences are related to the fine details of the GP and length of ovaries. In L. brevis , GP are oval, smooth, projected from body wall, and its ovaries extend along chaetigers 5–7 (or 8), whereas in L. hartmanae GP are globular, granulose, barely projected from body wall, and its ovaries extend along chaetigers 5–6.

Body polarity was correctly indicated in the original description. The records for the Northeastern Atlantic or Mediterranean Sea deserve confirmation; some of these records indicate shorter anal cirri ( Laubier 1972, Katzmann & Laubier 1974), and were found in deep water ( Chardy et al. 1973), whereas others having long digitate anal cirri, were found in shallower waters ( Martínez & Adarraga 2012). The Eastern Atlantic specimens are slightly darker, more contracted and their integument is less smooth than in the Western Atlantic specimens. In addition, the anal papillae are 1.5–2.0 times longer than wide, and always exposed regardless their contraction state, whereas in topotype specimens, the anal papillae are 2.5 times longer than wide and are often bent over the pygidium, being difficult to be detected in contracted pygidia. The contraction shows some segmental marks after chaetal bundles, such that if this contraction is not an artifact, genital papillae would be placed on chaetiger 7 because they are slightly ahead of the corresponding chaetal fascicles. Oocytes about 80 µm in diameter.

Riser (1987:215) found genital papillae as paired structures in male non-type specimens of L. brevis . Because they had not been found in females or perhaps because the specimens that Riser studied were not topotypes, Petersen (2000) regarded L. brevis as having the genital papillae probably unpaired, and with some degree of intraspecific variability in her key and comments about the species.

The finding of two different integument and body shape variants in the same sample is interesting. One is thicker, with a less transparent integument, and slightly brownish, especially in larger specimens. The other one is thinner, with a more transparent integument. No further difference can be found. The pygidium can be retracted such that the variations of its relative exposure do not have any diagnostic relevance. However, some specimens have two anal cirri; in some they are conical, blunt and short, whereas in other specimens, including topotypes of L. brevis , there are two digitate anal cirri.

Figures

FIGURE 2. Fauveliopsis armata Fauchald & Hancock, 1981, paratypes (LACM 1161). A. Methyl green stained, dorsal view, stereoscope. B. Same, dorsal view, compound microscope. C. Same, right side of anterior end. D. Same, posterior end, dorsal view. Scale bars: A, B: 250 µm, C: 60 µm, D: 80 µm.

FIGURE 26. Laubieriopsis brevis (Hartman, 1965). A. Paratype (LACM 528), dorsal view. B. Non-type specimen, ESE off Nantucket (USNM 1558268, Albatross 2084), mature female, anterior region, dorsal view (oocytes about 80 µm). C. Same, posterior end (arrow points to papillae). D. Non-type specimen, Eastern Atlantic (MNHN 901b), anterior end, dorsal view. E. Same, posterior region. F. Another, non-type specimen (MNHN 901b), dorsal view (inset: chaetiger 6 with paired genital papil- lae indicated by asterisks). Scale bars: A, B, F: 0.4 mm, C: 0.3 mm, D: 110 µm, E: 80 µm.

FIGURE 27. Laubieriopsis brevis Hartman, 1965, non-type specimens (LACM 7553, A126). A. Dorsal view (inset: posterior end). B. Anterior region, dorsal view. C. Another specimen, prostomium, frontal view (cilia covered by salt particles). D. Anterior chaetigers, chaetae. E. Another specimen, posterior end, frontal view (arrows point to anal cirri). Scale bars: A: 450 µm (inset: 200 µm), B: 170 µm, C, E: 50 µm, D: 15 µm.

FIGURE 28. Laubieriopsis brevis Hartman, 1965, non-type specimen (LACM Ch130). A. Anterior region, anterior end (AE) exposed (numbers indicate chaetigers). B. Same, seen from above (Pe: peristomium, Ph: pharynx). C. Same, close-up (Pr: prostomium, Ph: pharynx). D. Chaetigers 6–7, right parapodia, frontal view (asterisk indicates genital papilla). E. Same, close-up of genital papillae and chaetae of chaetiger 7. Scale bars: A: 140 µm, B: 110 µm, C: 40 µm, D: 90 µm, E 30 µm.