Antarctinoe ferox ( Baird, 1865 ) Barnich & Fiege & Micaletto & Gambi, 2006

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 : 68-73

Antarctinoe ferox ( Baird, 1865) comb. nov.

( Figures 12A–K , 13B )

Hermadion ferox Baird 1865, p 197 ; Monro 1929, p 163; Monro 1930, p 40, Figure 6 ; Knox and Cameron 1998, p 33, Figures 65–68.

Harmothoe ferox: Uschakov 1962, p 160 ; Averincev 1972, p 122, Table 1.

Hermadion rouchi Gravier 1911a, p 312 ; Gravier 1911b, p 82, Plate 3 Figures 33–34, Plate 4 Figures 45–51, Plate 7 Figure 74.

Eunoe hubrechti: Day 1967, p 62 , Figure 1.7.q–v (part). [not Evarne hubrechti McIntosh, 1900 ]

Harmothoe crosetensis type D: Averincev 1972, p 119, Table 1. [not H. crosetensis ( McIntosh, 1885) ]

Harmothoe crosetensis: Stiller 1996, p 35 , Plate 16 (part). [not H. crosetensis ( McIntosh, 1885) ] Eunoe spica Hartman 1978, p 134 , Figure 6a–e ; Stiller 1996, p 33, Plate 13. [new synonymy]

Type material

Hermadion ferox: BMNH 1971.242,? holotype (or syntype, not clearly stated in Baird 1865; cs, in bad shape), Antarctic Expedition, 74.5 ° S, 175.5 ° E, Ross Sea, 300 fathoms.

Eunoe spica: USNM 46582, holotype (checked by K. Fauchald, USNM, personal communication), International Weddell Sea Oceanographic Expedition, USCGS ‘‘Glacier’’, St. 69-1, 74 ° 28.19S, 30 ° 31.79W, 24 February 1969, 513 m, anchor dredge.

Additional material. Three spms (2 cs, 1 af), ANT XIII/3, 39/001, GSN; one spm. (cs), ANT XIII/3, 39/005, EBS; six spms (2 cs, 4 af), ANT XIII/3, 39/006, AGT; nine spms (4 cs, 5 af), ANT XIII/3, 39/011, GSN; 19 spms (11 cs, 8 af), ANT XIII/3, 39/012, GSN, one spm., SMF 15166 (cs), ANT XIII/3, 39/012, GSN; four spms (cs), ANT XIII/3, 39/012, GSN; one spm. (af), ANT XIII/3, 39/013, GSN; 18 spms (11 cs, 7 af), ANT XIII/3, 39/ 029, BPN; one spm. (cs), ANT XV/3, 48/197, AGT.

Diagnosis

Elytral margin smooth; elytral surface with conical microtubercles with blunt to pointed tip; thorn-shaped macrotubercles scattered in posterior half of elytron. Long, stout notochaetae projecting dorsally to meet mid-dorsally with blunt tip and shaft usually smooth. Large specimens without additional slender and capillary notochaetae. Neurochaetae falcate, unidentate.

Description

Since the holotype of Hermadion ferox is in bad shape, the description is based on an additional specimen from the Weddell Sea (SMF 15166) .

Body with 38 segments. At anterior end ( Figure 12A ), prostomium bilobed, with cephalic peaks; ceratophore of median antenna in anterior notch, style of median antenna smooth, distal part broken; lateral antennae inserted ventrally, styles missing; anterior pair of eyes situated dorsolaterally on widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps slightly papillate, tapering.

Tentaculophores inserted laterally to prostomium, each with a single notochaeta and a dorsal and ventral tentacular cirrus with styles missing. Second segment with first pair of elytra, biramous parapodia, and long buccal cirri.

Fifteen pairs of elytra, covering dorsum (in large specimens dorsum in mid-body region uncovered), on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last six segments cirrigerous; elytral margin smooth; elytral surface with conical microtubercles with blunt to pointed tip; thorn-shaped macrotubercles scattered in posterior half of elytron, mainly near outer lateral and posterior margin ( Figure 12B, C ). Cirrigerous segments with distinct, globular dorsal tubercles; dorsal cirri with cylindrical cirrophore and smooth style, slightly inflated subdistally, then abruptly tapering ( Figure 12D ). Ventral cirri with smooth, tapering style.

Parapodia biramous; notopodia of about same size as neuropodia 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 12E ).

Notochaetae of two kinds independent of size of individual: short, stout notochaetae with rows of spines and more or less pointed tip, and long, stout notochaetae projecting dorsally to meet mid-dorsally with blunt tip and shaft usually smooth (in smaller specimens few rows of spines present distally) ( Figure 12F–H ).

Neurochaetae falcate with unidentate tip; one or two neurochaetae with subdistal slit suggesting presence of secondary tooth (but never distinctly bidentate as in Harmothoe ) ( Figure 12I–K ).

Nephridial papillae distinct from segment 6.

Measurements

Additional specimen (SMF 15166), cs, figured herein ( Figure 12 ): L 44 mm, W 11 mm for 38 segments. Largest additional specimen found L 50 mm, W 15 mm for 42 segments; smallest found L 17 mm, W 5 mm for 39 segments.

Remarks

Although the type specimen of Hermadion ferox Baird, 1865 is in bad shape with no remaining elytra, the notochaetal characters together with the description given in Baird (1865) leave no doubt regarding its authenticity. Unfortunately Baird does not clearly state if his description is based on a single specimen, i.e the holotype, or on syntypes.

The type material of Hermadion rouchi Gravier, 1911 is not available in the MNHN in Paris and thus probably lost (cf. F. Pleijel, personal communication). But the description and figures by Gravier (1911b) are sufficient to synonymize this species with Antarctinoe ferox . This was also recognized by Monro (1929) who was the first to synonymize Hermadion rouchi with Hermadion ferox , and by Uschakov (1962) who considered the species to belong to the genus Harmothoe .

According to Monro (1930), Hermadion ferox is difficult to differentiate from Harmothoe crosetensis sensu Bergström (1916) which is considered herein to be synonymous with Harmothoe acuminata Willey, 1902 (see above). But Willey’s description and figures of his subspecies Harmothoe crosetensis acuminata are rather confusing. Our investigations of the respective type material showed that Harmothoe acuminata is easily distinguished from Antarctinoe ferox , the former having some middle neurochaetae with distinctly bidentate tip, short and long notochaetae orientated mostly laterally, and elytra with papillate margin and numerous elongate, pointed, spine-shaped macrotubercles, while A. ferox differs in its unidentate neurochaetae, very long and stout notochaetae orientated mostly mid-dorsally, and elytra with smooth margin and smaller, curved, thorn-shaped macrotubercles.

Besides the similar elytral ornamentation, Antarctinoe spicoides and A. ferox share the same type of short notochaetae and the same characteristic orientation of the very long, stout notochaetae pointing mostly mid-dorsally. But A. spicoides can be clearly separated from A. ferox by the presence of pin-like tips in the long, stout notochaetae and larger specimens showing additional slender and capillary notochaetae, while A. ferox is characterized by only a single kind of long, stout notochaetae with blunt tip and usually smooth shaft.

Within the specimens from station ANT XIII/3, 39/012 we observed two different morphs independent of the size of the individuals. Some specimens show pigmented transverse bands on the dorsum and at the elytral margin (in ethanol) together with very long, stout notochaetae extending to the elytrophores or dorsal tubercles of the opposite side (the holotype and the figured specimen belonging also to this morph). Other specimens from the same station are more or less unpigmented (in ethanol) and have long stout notochaetae extending only to about the mid-dorsum. Since the specimens were not sexually reproductive (i.e. dissection of gonads showed no clear distinction between immature sperm or eggs) we do not know if the occurrence of the two morphs is due to sexual dimorphism.

Distribution

Antarctic region: Marguerite Bay ( Gravier 1911a, 1911b), Weddell Sea (cf. also Hartman 1978; Stiller 1996), and Ross Sea (type locality).

Identification key to the species covered herein

1. Neurochaetae unidentate; stout notochaetae very long, mostly orientated dorsally to meet mid-dorsally; longest notochaetae distinctly longer than longest neurochaetae: Antarctinoe gen. nov.............. 2

– Neurochaetae bidentate or bi- and unidentate; long, stout notochaetae mostly orientated laterally; longest notochaetae never distinctly longer than longest neurochaetae: Harmothoe ................. 3

2. Long, stout notochaetae with rows of spines distally and pin-like tip; large specimens with additional fine, slender notochaetae with pointed to pin-like tip, and capillary notochaetae with pointed tip.. Antarctinoe spicoides ( Figures 10 , 11 )

– Long, stout notochaetae with blunt tip and shaft usually smooth; large specimens without additional slender and capillary notochaetae. Antarctinoe ferox ( Figure 12 )

3. Inner posterior margin of elytra with mound........... 4

– Inner posterior margin of elytra without mound.......... 5

4. Elytral mound with very long, filiform papillae, distinctly longer than those at adjacent margin; few conical to cylindrical macrotubercles occurring near posterior elytral margin.......... Harmothoe fullo ( Figure 4 )

– Elytral mound with short papillae, of same size as those at adjacent margin; spherical macrotubercles present at the centre of elytron and near posterior margin............... H. antarctica ( Figure 5 )

5. Elytra without distinct macrotubercles............. 6

– Elytra with macrotubercles................ 7

6. Anterior part of elytra covered with conical microtubercles of about same size (number of microtubercles and surface covered variable); outer lateral and posterior elytral margin with few, scattered papillae.... Harmothoe magellanica ( Figures 6 , 7 )

– Elytral surface densely covered by conical microtubercles with blunt tip in anterior half, becoming gradually larger towards posterior margin, with tips blunt to slightly multifid; outer lateral and posterior elytral margin with numerous papillae.......... Harmothoe crosetensis ( Figure 8 )

7. Elytral macrotubercles thorn- to spine-shaped.. Harmothoe acuminata ( Figure 9 )

– Elytral macrotubercles not thorn- or spine-shaped......... 8 8. Outer elytral margin with dense fringe of long, filiform papillae; posterior half of elytra with numerous, globular to conical macrotubercles.. Harmothoe fuligineum ( Figure 3 )

– Outer elytral margin with scattered, short papillae; elytral macrotubercles otherwise 9

9. Elytral macrotubercles pyriform to globose with or without distal papilla, occurring near outer and posterior margin... Harmothoe exanthema ( Figure 2 )

– Elytral macrotubercles conical; occurring mainly near posterior margin...................... Harmothoe spinosa ( Figure 1 )

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 10. Antarctinoe spicoides (holotype, ZMH P-18608). (A) Anterior end; palps and styles of antennae and cirri missing, except for left dorsal tentacular one; right tentaculophore and right second parapodium cut off; (B) right elytron from unknown segment; (C) detail of outer lateral margin of same; (D) right cirrigerous parapodium from mid-body region, posterior view; (E) distal half of short, stout notochaeta; (F) tip of long, stout notochaeta; (G) distal part of middle neurochaeta. Scale bars: 2 mm (A); 1 mm (B, D); 250 mm (C, E–G).

Figure 11. Antarctinoe spicoides (SMF 15165). (A) Left cirrigerous parapodium of segment 18, posterior view; (B) tip of long, stout notochaeta; (C) tip of short, stout notochaeta; (D) tip of fine, slender notochaeta; (E) tip of capillary notochaeta. Scale bars: 2 mm (A); 100 mm (B–E).

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).

Figure 13. (A) Living specimen of Harmothoe fuligineum; (B) living specimen of Antarctinoe ferox. Photographs: Martin Rauschert (AWI, Berlin).