Glandulospio orestes

Bick, Andreas, Guggolz, Theresa & Götting, Miriam, 2014, Spionidae (Polychaeta: Canalipalpata: Spionida) from seamounts in the NE Atlantic, Zootaxa 3786 (3), pp. 201-245 : 225-231

Glandulospio orestes gen. et sp. nov.

(Figures 11–14)

Holotype: NE Atlantic Ocean, Expedition DIVA 3, cruise METEOR ME 79-1: Little Meteor Seamount: 29°38.19’N 028°59.07’W, station 632, grab, depth 271.7 m, 17-Aug-2009, formalin: 1 af ( SMF 23335).

Paratypes: NE Atlantic Ocean Expedition DIVA 3, cruise METEOR ME 79-1: Little Meteor Seamount: 29°38.19’N 028°59.07’W, station 632, grab, depth 271.7 m, 17-Aug-2009, formalin: 9 af (ZSRO-P2316), 1 af (AM W46088), 1 af ( USNM 1231369), 3 af ( SMF 23337), 1 af dissected ( SMF 23336), 1 af SEM ( SMF 23338), 96% ethanol: 5 af (ZSRO-P2325), 4 af (ZSRO-P2326), 3 af (ZSRO-P2318), 10 af ( SMF 23353); Great Meteor Seamount: 30°00.00’N 028°29.99’W, station 659, epibenthic sledge, 287.7 m, 19-Aug-2009, 96% ethanol: 1 af with one palp ( SMF 23362).

Non– type material. NE Atlantic Ocean, Expedition DIVA 3, cruise METEOR ME 79-1: Irving Seamount: 31°56.98'N 027°56.66'W, station 683, grab, depth 281.1 m, 21-Aug-2009, 96% ethanol: 1 af (ZSRO-P2322); 31°56.98’N 027°56.69’W, station 686, grab, depth 280.6 m, 21-Aug-2009, formalin: 1 af (ZSRO-P2314); 31°56.96’N 027°56.55’W, station 680, grab, depth 281.9, 21-Aug-2009, formalin: 1 af (ZMH-P27556). Hyères Seamount: 31°26.40'N 028°56.27’W, station 671, grab, depth 288 m, 20-Aug-2009, formalin: 1 af (ZMH-P 27560). Great Meteor Seamount: 30°00.04’N 028°30.05’W, station 664, grab, depth 287.9 m, 19-Aug-2009, formalin: 4 af ( SMF 23340), station 663, grab, depth 287.1 m, 19-Aug-2009, 96% ethanol: 1 af (ZSRO-P2328), station 662, grab, depth 287.6 m, 19-Aug-2009, 96% ethanol: 1 af (ZSRO-P2327), formalin: 4 af ( SMF 23349), station 661, grab, depth 287.4 m, 19-Aug-2009, formalin: 2 af ( SMF 23347), 1 af (ZSRO-P2313), 1 af ( SMF 23345), 1 af ( SMF 23352), 1 af ( SMF 23363), station 660, grab, depth 287.2 m, 19-Aug-2009, formalin: 4 af ( SMF 23348), 2 af (ZMH-P 27555), 6 af (ZSRO-P2312); 29°44.24’N 028°24.54’W, station 657, epibenthic sledge, 285.5 m, 18-Aug-2009, 96% ethanol: 2 af ( SMF 23358); 29°44.13’N 028°24.91’W, station 656, epibenthic sledge, 283.3 m, 18-Aug-2009, 96% ethanol: 3 af (ZSRO-P2323); 29°42.17’N 028°22.96’W, station 650, grab, depth 289.2 m, 18-Aug-2009, formalin: 13 af (ZMH-P 27557), 96% ethanol: 5 af ( SMF 23361); 29°41.72’N 028°22.39’W, station 644, grab, depth 300.4 m, 18-Aug-2009, formalin: 1 af ( SMF 23341). Little Meteor Seamount: 29°38.19’N 028°58.98’W, station 631, grab, depth 272.3 m, 17-Aug-2009, formalin: 13 af (ZSRO-P2310); 29°38.18’N 028°58.86’W, station 630, grab, depth 272.3 m, 17-Aug-2009, 96% ethanol: 1 af (ZSRO-P2319), 7 af (ZSRO- P2324), 3 af ( SMF 23360); 29°38.18’N 028°59.26’W, station 634, grab, depth 276.7 m, 17-Aug-2009, formalin: 10 af (ZMH-P 27559), 1 af (ZSRO-P2308), 4 af (ZMH-P 27553), 8 af (ZMH-P 27558); 29°38.16’N 028°59.17’W, station 633, grab, depth 272.2 m, 17-Aug-2009, formalin: 2 af (ZSRO-P2317), 1 af ( SMF 23346); 29°36.32’N 028°59.93’W, station 625, grab, depth 276 m, 17-Aug-2009, formalin: 5 af (ZSRO-P2309), 47 af (ZSRO-P2311); 29°36.32’N 029°00.06’W, station 626, grab, depth 277.7 m, 17-Aug-2009, formalin: 11 af ( SMF 23342), 35 af ( SMF 23343), 1 af SEM ( SMF 23344); 29°36.29’N 028°59.34’W, station 622, grab, depth 267.5 m, 17-Aug-2009, 96% ethanol: 31 af ( SMF 23356), 6 af (ZSRO-P2321), 6 af ( SMF 23357); 29°36.29’N 028°59.68’W, station 624, grab, depth 274.2 m, 17-Aug-2009, 96% ethanol: 2 af (ZSRO-P2320), 38 af ( SMF 23355); 29°36.28’N 028°59.53’W, station 623, grab, depth 270.9 m, 17-Aug-2009, formalin: 14 af ( SMF 23339); 29°36.27’N 028°58.81’W, station 619, grab, depth 268.2 m, 17-Aug-2009, formalin: 6 af (ZMH-P 27554), 6 af (ZSRO-P2315), 7 af ( SMF 23350), 1 af SEM ( SMF 23351), 96% ethanol: 1 complete ( SMF 23354), 4 af ( SMF 23359).

Diagnosis: Anterolateral horns arising subanteriorly from prostomial margin, posterior part of prostomium extendend into short caruncle terminating at the end of chaetiger 1 (Figures 11A–B, 12A, 13). Nuchal organs with two pairs of ciliary bands (Figures 11A, 12A–B, 13A left), continue as metameric double-paired ciliary bands (=metameric dorsal ciliated organs) between transversal ciliated bands of consecutive segments, starting after transversal ciliated band on chaetiger 3, last pair usually before transversal ciliated band on chaetiger 6 or 7 (Figures 11A, 12A). Branchiae from chaetiger 1, branchiae of chaetigers 3–6 (7 in largest specimens) considerably longer than on previous chaetigers, on succeeding 3–4 chaetigers quickly decreasing in size (Figures 11A–B, 12A, 13A left, 14). Large glandular organs present in chaetigers 5–10. Neuropodial hooded hooks with pair of apical teeth above main fang from chaetiger 10 (from chaetiger 9 or 11 in juvenile or large adult specimens, respectively) (Figures 11C–D, 12C–D).

Description. Holotype anterior fragment (without palps) with 22 chaetigers, about 0.9 mm wide (at 4th chaetiger) and 3 mm in length. Widest anterior fragment of all examined specimens 1.3 mm wide (at chaetiger 4), 6.5 mm long for 22+ chaetigers; small complete specimen 0.4 mm wide (at chaetiger 4), 1.2 mm long for 15 chaetigers. The anterior and middle part of the body distinctly thicker than the abdominal part (characterized by the presence of neuropodial hooks), which is often broken off.

Anterolateral horns arising subanteriorly from prostomial margin, anterior part of prostomium ballooned and wider than posterior part, posterior part of prostomium extended into short caruncle terminating at end of chaetiger 1, with inconspicuous pigmented elevation, laterally accompanied by two short ciliary bands, occipital antenna absent; transverse depression between anterior and posterior part of prostomium present (Figures 11A–B, 12A, 13). Two pairs of red eyes usually visible in ethanol-fixed specimens, anterior pair crescent-shaped and further apart than posterior pair of rounded shape, the latter in front of prostomial elevation (Figure 13); eyes not present in holotype. Prostomium distinctly separated from peristomium by furrow, peristomial palps reaching chaetiger 8 at maximum. Nuchal organs with two pairs of ciliary bands: short median bands surrounding caruncle (with prostomial elevation) laterally and long lateral continuous ciliary bands starting between notopodia of first chaetiger and palps, from there running straight across first chaetiger to almost the middle of the dorsum and then turning posteriorly, extending until transverse ciliary band of third chaetiger (Figures 11A, 12A–B, 13A left); FIGURE 11. Glandulospio orestes gen. et sp. nov.: A. Anterior end, dorsal view. B. Anterior end, lateral view. C. Neuropodial hooded hook from 10th chaetiger, lateral view. D. Same in lateral oblique view. E. Sabre chaeta from 22nd neuropodium. F. Hook-accompanying capillary from anterior row of chaetae in 22nd neuropodium. G. Notochaeta from 2nd chaetiger.—All from type locality (SMF 23336, paratype), Scale: A, B 0.5 mm, C–G 10 µm.

FIGURE 12. Glandulospio orestes gen. et sp. nov.: A. Anterior end, dorsal view (arrow indicating prostomial elevation, also shown at higher magnitude in picture B). B. Detail of nuchal organ: short anterior pair of ciliary bands surrounding caruncle (with prostomial elevation). C. Tridentate hooded hook in neuropodium of chaetiger 15. D. Neuropodium of chaetiger 12; anterior row of simple capillaries accompanying hooded hooks, also sabre chaetae present in inferiormost position. E. View from ventral side at neuropodium of chaetiger 9 in situ, specimen embedded in glycerine (arrow pointing at gland inside the body partially seen through the body wall). F. Cross section through 8th chaetiger with large glandular organs visible laterally from the intestine; section dorsally disrupted. G. Gland openings in the region of neuropodial chaetae (8th chaetiger).—A, B from type locality (SMF 23338, paratypes), C, D specimens from Little Meteor Seamount (SMF 23351), E (SMF 23344) and F, G (ZSRO-P2313) all from Great Meteor Seamount. Scale: A 200 µm, B, D–F 20 µm, C, G 5 µm.

FIGURE 13. Glandulospio orestes gen. et sp. nov.: Examples for pigmentation observed in several specimens: A, left picture. Anterior end, dorsal view, pigment around prostomial elevation, between peristomium and 1st chaetiger, and along lateral long ciliary band of nuchal organ. A, right picture. Anterior end, ventral view, pigment ventrally across 3rd, 5th and less intense on 7th chaetiger visible, in addition on parapodial lamellae of several chaetigers. B. Pigmentation seen from above and from below in complete, juvenile specimen.—All specimens from Little Meteor Seamount; A, left picture, ethanol fixed (ZSRO-P2324), A, right picture, formalin fixed (ZMH-P27558), B ethanol fixed (SMF 23354).

double-paired ciliary bands (=metameric dorsal ciliated organs) between transversal ciliated bands in consecutive segments, starting after transversal ciliated bands on chaetiger 3, last pair usually before transversal ciliated band on chaetiger 6 or 7 (6 in holotype) (Figures 11A, 12A).

Branchiae from chaetiger 1, often continuing to end of fragment but easily lost after chaetiger 10, branchiae on first chaetiger short, about the length of the notopodial lamellae or only slightly longer, branchiae on second chaetiger stouter and almost twice the length of first branchiae, distinctly longer than notopodial lamellae, branchiae of chaetigers 3–6 (7 in largest specimens) considerably longer than on previous chaetigers, almost reaching midline dorsally but usually not touching each other, on succeeding 3–4 chaetigers (chaetigers 7–9 or 7/8– 10, holotype 7–9) branchiae quickly decreasing in size, eventually about the length or slightly shorter than notopodial lamellae, thinner than notopodial lamellae, afterwards similar until end of fragment; branchiae cirriform, in some middle chaetigers (3–7) branchiae basally fused with notopodial postchaetal lamellae, separated from lamellae in anteriormost and in posterior chaetigers (Figures 11A–B, 12A, 13A left, 14).

Large paired glandular organs present in chaetigers 5–10; each segment with one on each side of the body lateral to intestine; gland openings located in the region of neuropodial chaetae (Figure 12E–G).

First parapodium slightly shifted dorsally (Figure 11B). Notopodial postchaetal lamellae small, subtriangular with broad base throughout, partially fused with base of branchiae on chaetigers 3–7 ( Figure 14 ). Neuropodial postchaetal lamellae small, subtriangular with broad rounded base, slightly larger on middle chaetigers (about 5–9) ( Figure 14 ). Praechaetal lamellae absent, but bulge in front of notopodial chaetae present in chaetigers 8–12 (bulge stains well with methyl green).

Notopodial chaetae all capillaries, those of anterior chaetigers arranged in two rows: chaetae of anterior row shorter, slightly granulated (Figure 11G), chaetae of posterior row longer, lacking granulations; additional superior fascicle of very long, thin capillaries, without granulations; from about chaetiger 10 smooth capillaries of different lengths arranged in irregular rows. Neuropodia of anterior parapodia with capillaries arranged in two rows, similar to notochaetae but all chaetae of similar length; from about chaetiger 6 few smooth, long capillaries in inferiormost position; from chaetiger 10 (or 11, in largest specimen), in juvenile specimens from chaetiger 9, anterior row of thin, smooth capillaries present (Figures 11F, 12D), posterior row of capillaries replaced by single row of 3–7 (3–5 in holotype) hooded hooks, juvenile specimens with 1–2 hooks, hooks with pair of apical teeth above main fang (Figures 11C–D, 12C–D); in posterior chaetigers thin distally granulated sabre chaetae with narrow limbation present in inferiormost position (Figure 11E) (replacing few very long capillaries in this position in previous chaetigers, e.g. Figure 14 G–H).

Pygidium observed only in one juvenile specimen: four short anal cirri of about equal length and width (Figure 13B); lost in all other specimens.

Pigmentation. Pigmentation best visible in ethanol-fixed specimens, in formalin-fixed specimens very pale or completely lost, pigment lost in holotype. Reddish pigment most conspicuous on prostomial elevation posterior to second pair of eyes, dorsally and laterally between peristomium and first chaetiger, also posteriorly along lateral long ciliary band of nuchal organ, and ventrally across 3rd, 5th and less intense on 7th chaetiger (Figure 13). Pigment may be present laterally on chaetigers 3–16 between parapodial rami and in notopodial lamellae (here in particular from chaetiger 7), also in neuropodial lamellae of chaetigers 5–8. Pigment also sometimes present ventrally on chaetigers 8–12.

Methyl green staining pattern. Anterior part of prostomium with anterolateral horns and caruncle, peristomium, branchiae, postchaetal lamellae, and laterally rounded protuberance between neuro- and notopodium from about chaetiger (2)5–10(12) most intensively stained. Praechaetal bulges in notopodia of chaetigers 8–12 stain well with methyl green.

Ecology. Glandulospio orestes gen. et sp. nov. was found on seamounts in coral and crushed shell gravel in about 300 m water depth. In one large specimen from the Hyères seamount (an anterior fragment of 22 chaetigers, 1.1 mm wide, ZMH-P 27560) eggs are visible through the cuticle in parapodia of chaetigers 11–21; eggs with an ornamented egg envelope resembling honeycombs, eggs 100–120 µm in diameter.

Geographical distribution. Only known from the Little Meteor Seamount (type locality) and nearby Great Meteor and Irving Seamounts.

Etymology: oreas, ~oreadis - Latin for mountain-nymph, hill. The name refers to the occurrence of the species on three Atlantic seamounts, including the type locality on Little Meteor Seamount.

Remarks. Glandulospio orestes gen. et sp. nov. is the only representative of the newly described genus Glandulospio . The species is easily recognized based on the characters mentioned under ‘Remarks’ for the generic description.

Figures

FIGURE 14. Glandulospio orestes gen. et sp. nov.: A – I. Parapodium from chaetiger 1, 2, 3, 6, 7, 8, 9, 10, 18, all anterior view. — All from type locality (SMF 23336, paratype), Scale: all 0.1 mm.