Harmothoe samadiae Suárez-Morales and Salazar-Vallejo, 2025

Harmothoe samadiae Suárez-Morales and Salazar-Vallejo View in CoL sp. n.

( Figures 7–9 View Figure 7 View Figure 8 View Figure 9 )

Material examined

Holotype. ( NMNHIA 2000-2120 ), one paratype ( MNHN IA 2000-2121), both with same field data, Expedition Papua Niugini, Cape Croisiles, Research Vessel Alis, Sta. CP 4033 ( 04° 52 ʹ 06.8412” S, 145°52 ʹ 36.9228” E), 780 m, wood (tree stump), 16 December 2012, S. Samadi, leg ( Paratype damaged, body wall broken by pharynx eversion, and after removal of median parapodia; cephalic peaks distinct; lateral antennae, left palp, and left lower tentacular cirri on site; other cephalic appendages lost; tentaculophore with 3–4 chaetae; last left elytron on site, partially damaged by chaetal intrusion; two large parasites on each parapodium of chaetiger 21, one yellowish, the other whitish, and a smaller one on right parapodium of chaetiger 29; body 27 mm long, 8 mm wide, 40 chaetigers). GoogleMaps

Additional material

One specimen ( MNHN IA 2017–4000), Expedition Papua Niugini, Cape Croisiles , RV Alis, Sta . CP4033 ( 04°52 ʹ 06.8412” S, 145° 52 ʹ 36.9228” E), 780 m, 16 December 2012, S . Samadi, leg . (complete, slightly bent ventrally; regenerating posterior end; cephalic peaks sharp; prostomium with a protuberance over the right posterior region; left parapodium of chaetiger 16 removed for observation (kept in container); most elytra on site, covering dorsum; two parasitic copepods under fourth pair of elytra; neurochaetae bidentate, accessory denticles broken; body 10.5 mm long, 4 mm wide, 34 chaetigers).

One specimen ( MNHN IA 2021–82), Expedition Papua Niugini, Cape Croisiles , RV Alis, Sta . CP4029 ( 04°52 ʹ 42.8412” S, 145° 50 ʹ 59.1972” E), 680–689 m, 16 December 2012, S . Samadi, leg . (complete, bent ventrally; pharynx pale, breaking dorsal body wall; prostomium with small fleshy outgrowths along posterior margin (probably parasite fragments); left parapodia of chaetigers 15 and 17 removed for observation (kept in container), all elytra detached ( 3 in container); neurochaetae clearly bidentate, accessory denticle long, reaching main fang, mostly straight, some falcate; body 19 mm long, 6 mm wide, 36 chaetigers).

Type locality

Cape Croisiles , RV Alis, Sta . CP4033 ( 04°52 ʹ 06.8412” S, 145° 52 ʹ 36.9228” E), depth = 780 m.

Etymology

The species name honours Dr Sarah Samadi in recognition of her participation in the Tropical Deep Sea Benthos programme at the Muséum National d’Histoire Naturelle, Paris, including the expedition on which she led the field work, and during which the holotype was collected.

Diagnosis

Harmothoe without eyes. Cephalic peaks distinct. Elytra with short sparse fimbriae, and with macro- and microtubercles, conical to digitate, sometimes surpassing elytral margin. Notochaetae with sharp tips. Neurochaetae delicately bidentate, accessory denticle often eroded.

Description of type specimens

Holotype ( MNHN IA 2021–3) complete, most elytra lost ( Figure 8 View Figure 8 (A)), first left, fifth right elytra, and right parapodium of chaetiger 16 removed for observation (kept in container), body pale, middorsal wide band blackish (gut), paler along posterior region; a copepod parasite with 2 egg masses fixed dorsally on right parapodium of chaetiger 21, a smaller one on left parapodium of chaetiger 24; posterior chaetigers thinner, without parapodial wall; pharynx fully exposed, breaking apart; venter pale; body 22 mm long, 6 mm wide, 40 chaetigers.

Prostomium subhexagonal, wider than long, with cephalic peaks distinct ( Figure 8 View Figure 8 (B)). Without eyes; 2 oblique transverse thin depressions on each side about typical eye position. Median ceratostyle lost, median ceratophore about 3 times wider and longer than laterals. Lateral ceratostyles papillate, about half as long as palps. Palps massive, smooth, tapered into fine sharp tips. Facial tubercle pale, barely visible dorsally, distorted by everted pharynx.

Tentacular segment with 2 pairs of papillate cirri, right ones complete, left ones without dorsal cirrus, with 2 falcate, sharp chaetae. Second chaetiger without nuchal hood; ventral cirri twice longer than following ones. Nephridial papillae indistinct.

Pharynx brownish ( Figure 8 View Figure 8 (A)), 7 mm long (as long as first 15 chaetigers);2 pairs of blackish jaws, without accessory denticles; 11 pairs of marginal papillae, mostly eroded ( Figure 8 View Figure 8 (C)).

Elytra thin, whitish, with sparse fimbriae with short filaments, especially along posterior margin ( Figure 9 View Figure 9 (A)); first elytron round, following ones ovoid, longer than wide, overlapping laterally and probably reaching middorsally. Elytra with anterior area with very small microtubercles ( Figure 9 View Figure 9 (B)) or almost smooth ( Figure 9 View Figure 9 (C)), becoming larger towards external median area; insertion area transitional regarding abundance and of macrotubercles ( Figure 9 View Figure 9 (E)); becoming larger towards posterior external margin, with sparse fimbriae ( Figure 9 View Figure 9 (F)), fimbria shorter along inner margin ( Figure 9 View Figure 9 (G)), almost disappears in internal posterior region ( Figure 9 View Figure 9 (H)).

Parapodia biramous ( Figure 8 View Figure 8 (D)). Dorsal cirri tapered, not swollen subdistally, surface papillate ( Figure 8 View Figure 8 (E)). Notopodium with prechaetal lobe round, short, postchaetal lobe tapered. Notochaetae golden, abundant, of a single type, coarser than neurochaetae, notochaetae shorter and median directed upwards, longer directed laterally, each notochaeta with series of fine denticulations continued almost to the tip, tips sharp ( Figure 8 View Figure 8 (F)). Neuropodium larger than notopodium, prechaetal lobe elongate, postchaetal lobe round, shorter; acicular lobe with tiny supracicular lobe. Neurochaetae golden, abundant, of a single type, subdistally swollen, with series of long denticles along pectinate area, tips falcate, delicately bidentate ( Figure 8 View Figure 8 (G)), accessory denticle broken (most entire in MNHN IA 2021–82). Ventral cirri tapered.

Posterior region tapered; pygidum with anus terminal, anal cirri lost.

Remarks

As indicated in the key below, H. samadiae sp. n. groups with H. panamensis Kirkegaard, 1995 and H. ingolfiana Ditlevsen, 1917 because they have macrotubercles on the elytral surface. However, H. samadiae differs from the two other species because its elytra have macrotubercles abundant along posterior elytral area, whereas in the two other species they are sparse, mostly close to elytral margins.

In contrast, H. samadiae and H. vagabunda Pettibone, 1985a are the two only species recorded from wood – the former from a tree stump, the latter from experimental wood panels – but they are quite different in their morphology.

Distribution

Only known from the type locality, in wood, in sediments at 780 m water depth.

Key to Harmothoe eyeless species

(modified from Kirkegaard 1995, Barnich and Fiege 2009)

1 Elytra with macrotubercles... ......................................................................................................... 2

- Elytra without macrotubercles... .................................................................................................. 4

2(1) Macrotubercles few, digitate, close to posterior margin.. ................................................. 3

- Macrotubercles abundant, digitate, especially along posterior area; cephalic peaks distinct; neurochaetae bidentate.. .................................................................................................... .............................................................. H. samadiae View in CoL sp. n. Southwestern Pacific New Guinea

3(2) Cephalic peaks barely visible; macrotubercles digitate, tips smooth; neurochaetae bidentate.. ................................. H. panamensis Kirkegaard, 1955 View in CoL Eastern Central Pacific

- Cephalic peaks distinct; macrotubercles elongate, tips multispinous; neurochaetae uni- and bidentate.. ........... .......... H. ingolfiana Ditlevsen, 1917 View in CoL north-eastern Atlantic

4(1) Elytral margins fimbriate.. ............................................................................................................... 5 - Elytral margins smooth; neurochaetae uni- and bidentate... H. tenebricosa Moore View in CoL ,

1910 Eastern North Pacific

5(4) Fimbriae with short filaments.. ..................................................................................................... 6

- Fimbriae with long filaments; microtubercles conical smooth, and globose with tips with 4–8 cusps; neurochaetae bidentate.. .................................................................................... ................................................................................... H. derjugini Annenkova, 1937 Sea of Japan

6(5) Microtubercles of a single type.. .................................................................................................. 7 - Microtubercles of two types, short smooth or with cusps, long blunt or with cusps;

neurochaetae bidentate.. ...... ..... H. hollisi Pettibone, 1989b Eastern Northern Pacific

7(6) Neurochaetae bidentate... .............................................................................................................. 8 - Neurochaetae unidentate; microtubercles conical.. ..................................................................

............................................ H. anoculata Hartmann-Schröder, 1975 north-eastern Atlantic

8(7) Microtubercles digitate.. ....... ...... H. gordae Pettibone, 1990 Eastern Northern Pacific - Microtubercles conical.. ....... H. vagabunda Pettibone, 1985a north-western Atlantic