Harmothoe glabra ( Malmgren, 1866 )

Barnich, Ruth & Fiege, Dieter, 2009, Revision of the genus Harmothoe Kinberg, 1856 (Polychaeta: Polynoidae) in the Northeast Atlantic, Zootaxa 2104 (1), pp. 1-76 : 41-44

Harmothoe glabra ( Malmgren, 1866)

( Figs. 5 ; 20A–H )

Laenilla glabra Malmgren, 1866: 73 [note: paralectotype belongs to Malmgreniella andreapolis ].

Harmothoe glabra: Tebble & Chambers (1982) : 55, figs. 17c–e, 51–52.

Harmothoe (Harmothoe) glabra: Hartmann-Schröder (1996) : 45, fig. 11.

Malmgrenia glabra: Chambers & Muir (1997) : 128, fig. 38.

Harmothoe longisetis: Fauvel (1923) : 66, fig. 24a–g [part].

Type material. Laenilla glabra : lectotype (designated here, but selected by M. Pettibone, from two syntypes, other syntype attributed to Malmgreniella andreapolis ( McIntosh, 1874a) , cf. Pettibone 1993a, p. 25) SMNH- Type-2382, Sweden, Bohuslän, Väderöarna, 7 fms, leg. A. Goes.

Additional material. NE Atlantic: 1 spm. (af), SMF 17304, Vigdis 1999, St. 11-1, 30 May 1999, 61°22'00.16'' N, 02°07'38.25'' E, 277 m, ded. A. Sikorski. 1 spm., Akvaplan-Niva Collection, Vigdis 1999, St. 3-5, 31 May 1999, 61°23'41.47'' N, 02°04'20.13'' E, 278 m. 1 spm. (af, juv.), SMF 17303, Gullfaks B 1999, St. 2-2, 16 June 1999, 61°11'54.62'' N, 02°12'15.62'' E, 140 m, ded. A. Sikorski. 2 spms. (juv.), Akvaplan-Niva Collection, Gullfaks B 1999, St. 14-4, 16 June 1999, 61°06'00.88'' N, 02°11'09.00'' E, 134 m. 1 spm. (af), SMF 17305, Gullfaks C 1999, St. 6-2, 17 June 1999, 61°13'02.38'' N, 02°16'45.00'' E, 220 m, ded. A. Sikorski. 2 spms., SMF 17302, 17307, Vigdis 2005, St. IT 4-5, 11 June 2005, 61.39112° N, 2.07830° E, 283 m, ded. A. Sikorski. 1 spm. (af), SMF 17306, Tordis 2005, St. 9-3, 15 June 2005, 61.27299° N, 2.11563° E, 197 m, ded. A. Sikorski .

Diagnosis. Anterior pair of eyes dorsolateral slightly in front of widest part of prostomium. Prostomium with small, rather indistinct cephalic peaks. Elytral margin and surface with scattered, short papillae; conical microtubercles mainly present in anterior half of elytron, some scattered in posterior half. Neuropodia with remarkably long, digitiform supra-acicular process.

Description (based on lectotype).

Body with 38 segments. At anterior end ( Fig. 20A ), prostomium bilobed, with small, rather indistinct cephalic peaks; ceratophore of median antenna in anterior notch, lateral antennae inserted ventrally, styles of antennae papillate, tapering; anterior pair of eyes situated dorsolaterally slightly in front of widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps papillate, tapering.

Tentaculophores inserted laterally to prostomium, each with two notochaetae and a dorsal and ventral tentacular cirrus, styles of cirri papillate, tapering. Second segment with first pair of elytra, biramous parapodia, and long buccal cirri. Following segments with tapering, short ventral cirri.

Fifteen pairs of elytra, covering dorsum, on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last six segments cirrigerous; elytral margin and surface with scattered, short papillae; conical microtubercles mainly present in anterior half of elytron, some scattered in posterior half. ( Fig. 20B,C ). Cirrigerous segments with distinct dorsal tubercles; dorsal cirri with cylindrical cirrophore, style papillate, tapering.

Parapodia biramous; notopodia with elongate acicular lobe; neuropodia with elongate prechaetal acicular lobe with remarkably long, digitiform supra-acicular process; neuropodial postchaetal lobe shorter than prechaetal lobe, rounded; tips of noto- and neuroacicula penetrating epidermis ( Fig. 20D ). Notochaetae stouter than neurochaetae; with distinct rows of spines and blunt tip ( Fig. 20E ); neurochaetae with distinct rows of spines, middle ones bidentate with long, slender secondary tooth, upper and lower ones unidentate, the latter with sharp pointed tip ( Fig. 20F–H ).

Measurements. Lectotype of Laenilla glabra , SMNH-Type-2382 ( Fig. 20A–H ): L 37 mm, W 8 mm for 38 segments.

Remarks. In the past this species was either attributed to the genus Harmothoe or to Malmgreniella resp. Malmgrenia . Re-evaluation of the lectotype of Laenilla glabra and additional material showed that the species has only small to minute cephalic peaks, but the lateral antennae are distinctly inserted ventrally, thus it has to be considered as a Harmothoe (in contrast to Barnich & Fiege (2000) p. 1905). Moreover, Harmothoe glabra has often been confused with H. longisetis ( Grube, 1863) (e.g. in Fauvel 1923). The latter species is probably confined to the southern part of the Northeast Atlantic and the Mediterranean; it is mainly distinguished by its elytra without papillae at margin and surface.

Confusion is possible between H. glabra and anterior fragments or juveniles of Leucia violacea ( Storm, 1879) ; both have similar elytra with conical microtubercles and scattered papillae, but in L. violacea some rather indistinct, low soft macrotubercles are present, especially in the anteriormost elytra (see Fig. 2 ). Complete adult Leucia specimens are easily distinguished due to their 16 pars of elytra (for description and figures of L. violacea , see Fiege & Barnich, in press).

Distribution. Arctic, North Atlantic to the Channel, and North Sea to the Öresund.

Habitat. Reported from various substrata from the eulittoral down to 1400 m; also occurring in brackish water.

Figures

FIGURE 2. Identification characters of Leucia violacea, Harmothoe fraserthomsoni, Leucia nivea, Acanthicolepis asperrima, Harmothoe aspera, and H. serrata.

FIGURE 5. Identification characters of Harmothoe fernandi n. sp., H. oculinarum, H. gilchristi, H. aequespina, H. glabra, and H. viridis.

FIGURE 20. Harmothoe glabra (lectotype, SMNH-Type-2382). (A) anterior end; right palp and style of median antenna missing; parapodia of right side cut off; (B) left elytron from unknown segment, free in vial; (C) detail of posterior margin of same; (D) right cirrigerous parapodium from segment 13, posterior view; (E) tip of long notochaeta; (F) tip of upper neurochaeta; (G) tip of middle neurochaeta; (H) tip of lower neurochaeta. (Scales: A, D = 1 mm; B = 2 mm; C = 100 µm; E–H = 50 µm).