Harmothoe crosetensis ( McIntosh, 1885 )

Barnich, R., Fiege, D., Micaletto, G. & Gambi, M. C., 2006, Redescription of Harmothoe spinosa Kinberg, 1856 (Polychaeta: Polynoidae) and related species from Subantarctic and Antarctic waters, with the erection of a new genus, Journal of Natural History 40 (1 - 2), pp. 33-75 : 56-59

Harmothoe crosetensis ( McIntosh, 1885)

( Figure 8A–I ; Table III)

Lagisca crosetensis McIntosh 1885, p 88 , Plate 8 Figure 6 , Plate 13 Figure 2 , Plate 18 Figure 7 , Plate 11A Figures 4–6 .

Harmothoe crosetensis laciniata Willey 1902, p 267 . [new synonymy]

Harmothoe crosetensis type A: Uschakov 1962, p 159.

Evarne kerguelensis McIntosh 1885, p 97 , Plate 6 Figure 4 , Plate 19 Figure 6 , Plate 6A Figures 12 –14.

Harmothoe spinosa fullo Willey 1902, p 265 , Plate 43 Figures 1 , 4 , 7 . [new synonymy] Harmothoe spinosa fullo lagiscoides Willey 1902, p 265 , Plate 43 Figure 6 .

Harmothoe spinosa lagiscoides: Gravier 1911b, p 92 , Plate 6 Figures 64–69.

Harmothoe lagiscoides: Bergström 1916, p 282 , Plate 2 Figures 2 , 3 ; Uschakov 1962, p 157, Plate Figures D–E; Day 1963, p 389.

Harmothoe gruzovi Averincev 1972, p 120 , Plate 1 Figures 1–7 . [new synonymy]

Type material

Lagisca crosetensis: BMNH 1885.12.1.68, lectotype (cs in two fragments, right half of pf cut off; designated, described, and figured herein) and BMNH 2005.2454, paralectotype (af), ‘‘ Challenger’ ’ Expedition, St. 147, 46 ° 169S, 48 ° 279E, near the Crozet Islands, 30 December 1873, 1600 fathoms, diatom ooze.

Evarne kerguelensis: BMNH 1885.12.1.77, syntypes (numerous specimens, juveniles), ‘‘ Challenger’ ’ Expedition, Kerguelen , off Christmas Harbour , 120 fathoms. BMNH 1885.12.1.80, syntype (af), ‘‘ Challenger’ ’ Expedition , Kerguelen , Cape MacLear. BMNH 1921.5.1.490, six syntypes (3 cs, 3 af, 1 pf), ‘‘Challenger’’ Expedition, Kerguelen, harbour, 120 fathoms.

Harmothoe spinosa fullo: BMNH 1902.1.8.86, holotype (af), ‘‘ Southern Cross’ ’ Expedition 1898–1900, Cape Adare .

Harmothoe spinosa fullo lagiscoides: BMNH 1902.1.8.97, holotype (cs), ‘‘ Southern Cross’ ’ Expedition 1898–1900, Cape Adare , 13 November 1899, 8.5 fathoms.

Harmothoe crosetensis acuminata: BMNH 1902.1.8.93–4, lectotype (cs in two fragments) and BMNH 2005.2455, paralectotype (cs, strongly bent), ‘‘ Southern Cross’ ’ Expedition, Cape Adare , 9 January 1900, 26 fathoms (see description of Harmothoe acuminata below).

Harmothoe gruzovi: ZISP 5, paratype (cs), 11. Complex Antarctic Expedition, St. G, Davis Sea, 1 February 1966, 45 m, rocks, qualitative sample.

Diagnosis

Elytral margin with digitiform papillae getting shorter towards posterior margin; elytral surface densely covered by microtubercles, being conical, elongate with blunt tip in anterior half, becoming gradually larger towards posterior margin, with blunt to slightly multifid tip.

Description (based on lectotype of Lagisca crosetensis )

Body with 36 segments. At anterior end ( Figure 8A ), prostomium bilobed, with cephalic peaks; ceratophore of median antenna in anterior notch, style of median antenna missing; lateral antennae inserted ventrally with styles missing; anterior pair of eyes situated dorsolaterally on widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps missing.

Tentaculophores inserted laterally to prostomium, each with one or two notochaetae and a dorsal and ventral tentacular cirrus with styles of cirri papillate, abruptly tapering subdistally (style of left and right dorsal and left ventral tentacular cirri missing). Second segment with first pair of elytra, biramous parapodia, and long buccal cirri.

Fifteen pairs of elytra, covering dorsum, on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last four segments cirrigerous; outer lateral margin of elytra with digitiform papillae getting shorter towards posterior margin; posterior half of elytral surface also covered by papillae; elytral surface densely covered by microtubercles, being conical, elongate with blunt tip in anterior half, becoming gradually larger towards posterior margin, with blunt to slightly multifid tip ( Figure 8B–D ). Cirrigerous segments with distinct dorsal tubercles; dorsal cirri with cylindrical cirrophore, style missing on all segments. Ventral cirri with smooth to papillate, tapering style.

Parapodia biramous; notopodia with elongate acicular lobe; neuropodia with elongate prechaetal acicular lobe with digitiform supra-acicular process; neuropodial postchaetal lobe shorter than prechaetal lobe, rounded; tips of noto- and neuroacicula penetrating epidermis ( Figure 8E ). Notochaetae stouter than neurochaetae; notochaetae with distinct rows of spines and short, bare, blunt tip ( Figure 8F, G ); neurochaetae falcate, with rows of spines distally; tip of neurochaetae bidentate with secondary tooth, some lower neurochaetae unidentate ( Figure 8H, I ).

Nephridial papillae distinct from segment 6.

Measurements

Lectotype of Lagisca crosetensis (BMNH 1885.12.1.68), cs in two fragments, figured herein ( Figure 8 ): L 18.5 mm, W 6.5 mm for 36 segments; largest syntype of Evarne kerguelensis (BMNH 1921.5.1.490), cs: L 14, W 4 mm for 36 segments; holotype of Harmothoe spinosa fullo (BMNH 1902.1.8.86), af with few last segments missing: L 32 mm, W 10 mm for 33 segments; holotype of H. spinosa fullo lagiscoides (BMNH 1902.1.8.97), cs: L 46 mm, W 11 mm for 40 segments; paratype of H. gruzovi (ZISP 5), cs: L 24 mm, W 7 mm for 39 segments.

Remarks

Willey (1902) established the subspecies Harmothoe crosetensis acuminata for specimens collected by the ‘‘Southern Cross’’ Expedition which he considered to be closely related to Lagisca crosetensis McIntosh, 1885 , collected during the ‘‘Challenger’’ Expedition. For the latter Willey created the subspecies Harmothoe crosetensis laciniata . The comparison of our material from the Weddell Sea with the types of Harmothoe crosetensis ( McIntosh, 1885) and H. crosetensis acuminata Willey, 1902 revealed that the differences between H. crosetensis and Willey’s subspecies are strong enough to raise the latter to species level, thus we establish the name Harmothoe acuminata Willey, 1902 herein (see below). Furthermore, the subspecies name laciniata is not to be used for H. crosetensis ( McIntosh, 1885) subsequently.

Harmothoe crosetensis differs significantly from H. acuminata due to its elytral and chaetal characters. Elytra of H. crosetensis are densely covered by microtubercles, being conical in the anterior part, becoming gradually larger towards the posterior margin, with blunt or slightly multifid tips (‘‘laciniate’’, cf. Willey 1902; Figure 8B–D ). In contrast elytra of H. acuminata differ clearly in size and shape of the tubercles, conical microtubercles with pointed or blunt tip being present near the anterior margin and the thorn- to spine-shaped macrotubercles with sharp pointed tip on the central and posterior part of the elytra ( Figure 9B–D ). Regarding the chaetae, H. crosetensis is characterized by notochaetae with short, bare, blunt tip and numerous bidentate neurochaetae with distinct, slender secondary tooth ( Figure 8F–I ), while in H. acuminata tips of notochaetae have a comparatively long bare part and neurochaetae are mostly unidentate, with only some middle neurochaetae being bidentate with minute secondary tooth ( Figure 9F–J ).

In his paper of 1916 Bergström supposed that Evarne kerguelensis McIntosh, 1885 and Harmothoe spinosa fullo lagiscoides Willey, 1902 might be synonyms of Harmothoe crosetensis . Having checked the type material listed above we confirm this view and add to this synonymy also H. spinosa fullo Willey, 1902 and H. gruzovi Averincev, 1972 .

The fact that H. crosetensis fullo lagiscoides is herein synonymized with H. crosetensis allows us now to raise H. lagiscoides serrata Day, 1963 definitely to species level. The latter subspecies had been studied by Barnich and Fiege (2000) in a partial revision of the Mediterranean Harmothoe species , but since the authors had not started to investigate the Antarctic species of Harmothoe at that time, the decision to raise this subspecies to species rank had to be postponed. Harmothoe serrata Day, 1963 mainly differs from H. crosetensis in its elytra with a row of slender, thorn-shaped macrotubercles with pointed tip near the posterior margin, and the thorn-shaped, pointed microtubercles on the elytral surface. In H. crosetensis distinct macrotubercles are not present; microtubercles are conical, elongate with blunt tip in anterior half, becoming gradually larger towards posterior margin, with blunt to slightly multifid tip.

Distribution

Subantarctic region: Crozet Islands (type locality) and Kerguelen Islands ; Antarctic region : Graham Land ( Bergström 1916), Davis Sea , and Cape Adare .

Figures

Figure 1. Harmothoe spinosa (holotype, SMNH-type-409). (A) Anterior end; palps and styles of antennae and cirri missing, right 2nd and 3rd parapodia cut off; (B) right elytron from anterior body region; (C) left elytron from segment 2; (D) detail of posterior margin of same; (E) right cirrigerous parapodium of segment 16, posterior view, style of dorsal cirrus missing; (F) short notochaeta; (G) long notochaeta; (H) tip of same; (I) middle neurochaeta; (J) tip of same; (K) tip of upper neurochaeta; (L) tip of lower neurochaeta. Scale bars: 1 mm (A–C); 250 mm (D, F, G, I); 500 mm (E); 50 mm (H, J–L).

Figure 2. Harmothoe exanthema (holotype; ZMUC POL 1671). (A) Anterior end; style of right dorsal cirrus of segment 3 missing; (B) right elytron from mid-body region; (C) detail of outer lateral margin of same; (D) macrotubercles from posterior part of elytron; (E) right cirrigerous parapodium of unknown segment, posterior view, style of dorsal cirrus missing; (F) long notochaeta; (G) tip of same; (H) middle neurochaeta; (I) tip of same; (J) tip of upper neurochaeta; (K) tip of lower neurochaeta. Scale bars: 1 mm (A, B); 250 mm (C, D, F, H); 500 mm (E); 50 mm (G, I–K).

Figure 3. Harmothoe fuligineum (SMF 15162). (A) Anterior end; styles of left lateral antenna, left and right dorsal and left ventral tentacular cirri, and right dorsal cirrus of segment 3 missing; (B) right elytron of segment 5; (C) detail of area near outer lateral margin of same; (D) left cirrigerous parapodium of segment 12, posterior view, style of dorsal cirrus missing; (E) long notochaeta; (F) tip of same; (G) middle neurochaeta; (H) tip of same; (I) tip of upper neurochaeta; (J) tip of lower neurochaeta. Scale bars: 2 mm (A, B); 250 mm (C); 500 mm (D); 250 mm (E, G); 100 mm (F, H–J).

Figure 4. Harmothoe fullo (lectotype, ZMB 685). (A) Anterior end; style of right dorsal tentacular cirrus regenerating; (B) left elytron from unknown segment in mid-body region; (C) detail of mound of same; (D) right elytron from unknown segment in mid-body region; (E) right elytragerous parapodium of segment 11, posterior view; (F) long notochaeta; (G) tip of same; (H) middle neurochaeta; (I) tip of same; (J) tip of upper neurochaeta; (K) tip of lower neurochaeta. Scale bars: 2 mm (A, B, D); 250 mm (C); 500 mm (E); 250 mm (F, H); 100 mm (G, I– K).

Figure 5. Harmothoe antarctica (lectotype, BMNH 1885.12.1.59). (A) Anterior end; right palp and style of median antenna missing; (B) left elytron from unknown segment in mid-body region; (C) detail from posterior margin of same; (D) right elytragerous parapodium from unknown segment, anterior view; (E) long notochaeta; (F) tip of same; (G) middle neurochaeta; (H) tip of same; (I) tip of upper neurochaeta; (J) tip of lower neurochaeta. Scale bars: 2 mm (A, B); 250 mm (C, E, G); 1 mm (D); 100 mm (F, H–J).

Figure 6. Harmothoe magellanica (lectotype, BMNH 1885.12.1.69). (A) Anterior end; palps and styles of antennae and cirri missing; (B) left elytron from unknown segment in mid-body region; (C) microtubercles from same; (D) left elytron from unknown segment in posterior body region; (E) dorsal cirrus from unknown segment; (F) right cirrigerous parapodium from unknown segment, posterior view, style of dorsal cirrus missing; (G) long notochaeta; (H) tip of same; (I) middle neurochaeta; (J) tip of same; (K) tip of upper neurochaeta; (L) tip of lower neurochaeta. Scale bars: 2 mm (A, B, D); 100 mm (C); 1 mm (E); 500 mm (F); 250 mm (G, I); 50 mm (H, J–L).

Figure 7. Harmothoe magellanica (SMF 15163). (A) Left elytron of segment 7; (B) detail of outer lateral margin of same. Scale bars: 1 mm (A); 100 mm (B).

Figure 8. Harmothoe crosetensis (lectotype, BMNH 1885.12.1.68). (A) Anterior end; palps and styles of antennae and cirri missing, except for right ventral tentacular one; (B) left elytron from unknown segment in mid-body region; (C) various microtubercles of same; (D) detail of posterior margin of same; (E) right cirrigerous parapodium from unknown segment, posterior view, style of dorsal cirrus missing; (F) long notochaeta; (G) tip of same; (H) middle neurochaeta; (I) tip of same. Scale bars: 1 mm (A, B); 250 mm (C, D); 250 mm (E, F, H); 100 mm (G); 50 mm (I).

Figure 9. Harmothoe acuminata (lectotype, BMNH 1902.1.8.93–4). (A) Anterior end; styles of median antenna and right dorsal tentacular cirrus missing, tips of styles of remaining tentacular cirri broken; (B) left elytron of segment 5; (C) detail from area near anterior margin of same; (D) detail of posterior margin of same; (E) right elytragerous parapodium from mid-body region, posterior view; (F) long notochaeta; (G) middle neurochaeta; (H) tip of same; (I) tip of upper neurochaeta; (J) tip of lower neurochaeta. Scale bars: 2 mm (A); 1 mm (B); 250 mm (C, D, F, G); 500 mm (E); 50 mm (H–J).

Figure 12. Antarctinoe ferox (SMF 15166). (A) Anterior end; styles of antennae and cirri missing, except for median antenna, but here tip broken; (B) right elytron from unknown segment in mid-body region; (C) detail of posterior margin of same; (D) distal half of dorsal cirrus from mid-body region; (E) right elytragerous parapodium of segment 15, anterior view; (F) short, stout notochaeta; (G) tip of same; (H) long, stout notochaeta; (I) middle neurochaeta; (J) tip of same; (K) tip of middle neurochaeta with subdistal slit. Scale bars: 2 mm (A, B, D–F, H, I); 250 mm (C, G, J, K).