Lygdamis mariae, Salazar-Vallejo & León-González, 2025

Salazar-Vallejo, Sergio I. & León-González, J. Angel De, 2025, Additional new species of marine annelids from Clipperton Island (Nereididae: Pilargidae: Sabellariidae), European Journal of Taxonomy 1026, pp. 1-29 : 16-22

Lygdamis mariae sp. nov.

urn:lsid:zoobank.org:act:

Figs 3–4, Table 1

Idanthyrsus pennatus Hartman, 1939: 19 (non Peters, 1854).

Lygdamis nesiotes Hartman, 1944: 332–333 (non Chamberlin, 1919).

Diagnosis

Lygdamis with outer paleae smooth, of a single type, straight, solid, not annulate, aristate, tips bent 140–150°, 34 per side; inner paleae 14 per side; median organ tapered, blunt; nuchal hooks tapered, tips long, wide, sharp.

Etymology

The species is named after Dr María Capa, in recognition of her many publications on taxonomy of marine annelids, and especially after her studies on sabellariid polychaetes which were very useful during this contribution. The specific epithet is a noun in the genitive case (ICZN 1999, Art. 31.1.2).

Type material

Holotype

FRANCE • complete spec.; Clipperton Island , stn 36; 10°17.49′ N, 109°13.56′ W; depth 54 m; 27 Jan. 2005; S. Hourdez, K.-L. Kaiser and J.-M. Bompar leg.; anchoring of Rara Avis ; MNHN IA-2000-2109 .

Paratypes

FRANCE • 1 complete spec.; same data as for holotype; paratype breaking in two; MNHN IA-2000-2110 • 5 complete specs; Clipperton Island , stn 10; 10°17.31′ N, 109°12.19′ W; depth 13 m; 17 Jan. 2005; J.-M. Bouchard, L. Albenga and L. Dugrais leg.; coral rubble, suction pump, one still in tube, another one too twisted, colorless; ECOSUR 320 • 2 complete specs; Clipperton Island , stn 17; 10°19.22′ N, 109°13.39′ W; depth 23 m; 20 Jan. 2005; J.-M. Bouchard, L. Albenga and L. Dugrais leg.; epifaunal organisms, hand collecting, opercula barely pigmented; MNHN IA-2000-2111 • 1 complete spec.; Clipperton Island , stn 20; 10°17.50′ N, 109°13.55′ W; depth 20 m; 22 Jan. 2005; J.-M. Bouchard, L. Albenga and L. Dugrais leg.; anchoring point of Rara Avis , coral rubble, colorless, with tube fragments, first branchiae duplicate; MNHN IA-2000-2112 • 5 complete specs; Clipperton Island , stn 25; 10°19.34′ N, 109°13.40′ W; depth 18 m; 23 Jan. 2005; S. Hourdez and K.-L. Kaiser leg.; coral rubble, platform margin, one in tube, colorless, anal peduncle contracted, blackish, smallest specimen medially brownish; ECOSUR 321 • 2 complete specs; Clipperton Island , stn 27; 10°18.01′ N, 109°13.87′ W; depth 1 m; 23 Jan. 2005; S. Hourdez and K.-L. Kaiser leg.; in front of Camp Bougainville, colorless; MNHN IA-2000-2113 • 1 complete spec.; Clipperton Island , stn 30; 10°18.72′ N, 109°12.01′ W; depth 15 m; 24 Jan. 2005; S. Hourdez, K.-L. Kaiser and J.-M. Bompar leg.; coral rubble and red algae, colorless, precaudal region with a band of tiny black spots, wider mid-ventrally; ECOSUR 322 • 1 anterior fragm.; Clipperton Island , stn 31, East of Port Jaouen; 10°17.45′ N, 109°13.26′ W; depth 1 m; 24 Jan. 2005; S. Hourdez and K.-L. Kaiser leg.; colorless; MNHN IA-2000-2114 .

Description ( holotype)

BODY. Complete, mature specimen, preserved in tube, posterior region breaking off. Body 52 mm long, 4 mm wide, 54 chaetigers. Body pale; operculum dark brown, especially laterally with pale spots below marginal cirri ( Fig. 3A–C); prepygidial parapodia with interramal glandular ridge, brownish ( Fig. 3E).

OPERCULUM. Oblique, bent ventrally, dorsally depressed into darker concavity ( Fig. 3A). Opercular paleae golden; outer paleae aristate, tips bent 140°–150°, 56 per side, core solid, non-annulate ( Fig. 4A); inner paleae straight to slightly bent, darker, core brownish ( Fig. 4B), 22 per side. Marginal papillae cirriform, basally wider, tapered, blunt, larger posteriorly, decreasing in size anteriorly ( Fig. 3C), papillae with anterior surface darker, lateral paler areas extended into opercular margin ( Fig. 3A), 18 papillae per side. Opercular ventral surface with 11 oblique series of tentacles per side, tentacular series longer basally, shorter distally ( Fig. 3B).

PALPS. Tapered, contracted, one visible ventrally ( Fig. 3B), other hidden between tentacles. Mouth U-shaped, lateral lips foliose, partially covering mouth opening.

NUCHAL HOOKS. Large, tapered, falcate, sharp, completely covered by pale, hook foliose projection ( Fig. 3D); hooks noted because of their darker pigmentation. In one paratype ( Fig. 4C) sharp, long, wide, with handles annulate. Median organ shorter than palps, tapered, tip blunt, blackish, with series of lateral eyespots, visible close to nuchal hooks.

THORAX. With 2 chaetigers without notochaetae. Chaetiger 1 with capillary neurochaetae and long, conical ventral cirrus directed ventrally, reaching mouth opening. Chaetiger 2 with capillary neurochaetae and long, conical ventral cirrus directed anteriorly, shorter than one present in chaetiger 1, and 2 slightly shorter cirri directed dorsally. Branchiae cirriform, tapered, from chaetiger 2, continued through 25 more segments.

PARATHORAX. With 4 biramous chaetigers with paleae and capillaries in both rami. Notopodia 4 × as long as neuropodia, dorsal cirri digitate on a swollen, wide conical base ( Fig. 4D); neuropodial cirri conical, blunt, as long as wide ( Fig. 4E). Notochaetae directed posteriorly, 10–12 per ramus, increasing in number posteriorly; neurochaetae directed anteriorly, 7–9 per ramus, increasing in number posteriorly; tips finely denticulate ( Fig. 4E, inset).

ABDOMEN. With parapodia biramous, first two chaetigers with longer notopodia; successive notopodia half as long. Notopodia uncinigerous, foliaceous, short, curved lobes with abundant uncini ( Fig. 4F), each with 8–9 transverse rows of denticles, mostly paired ( Fig. 4F, upper inset). Neuropodia reduced to short chaetal lobe; neurochaetae capillaries, thicker ones verticillate denticulate, thinner ones denticulate ( Fig. 4F). Prepygidial abdominal segments with notopodia reduced to short fan-shaped lobes, with glandular pigmented ridge between parapodial rami ( Fig. 3E).

CAUDA. Short, tubular, bent ventrally, damaged, without cirri.

Variation

The variation of some morphological features in 16 specimens is shown in Table 1. All features are size-dependent. Specimens were 12–52 mm long (mean 30.7 mm); smaller specimens were pale, especially if preserved outside their tubes, larger specimens and those preserved in tubes are darker. Their opercula had 15–56 outer (mean 34), and 6–22 inner (mean 14) paleae, and 8–18 marginal papillae (mean 14). The latter are usually blunt, shorter in smaller specimens and progressively smaller towards the dorsalmost position. The second parathoracic chaetiger had 7–17 notochaetal (mean 11), and 4–8 neurochaetal lanceolate paleae (mean 6). The median organ was never truncate, it was mostly blunt, but in three cases it had a more defined tip. Most specimens had two hooks, golden in smaller, brownish in larger specimens; only two specimens had one of them duplicate. The depressed lobe covering the falcate dorsal hook tip was covering the hooks completely in 4 specimens, medially in 11 specimens, and basally in 2; the latter might be due to partial damages due to abrasion during sampling. There were 19–35 pairs of branchiae (mean 25); anterior branchiae longer, progressively smaller posteriorly, often detached. The cauda, or anal peduncle, was always very short, 0.3–1.7 mm long. Specimens larger than 25 mm had hypertrophied gonads along posterior body half; smaller ones are juveniles.

Distribution

Only known from Clipperton Island, on rocky bottoms, 1–54 m depth; some Eastern Pacific records of L. nesiotes ( Chamberlin, 1919) might represent this species but there are not enough details in earlier records to clarify this.

Remarks

Lygdamis mariae sp. nov. resembles L. nesiotes ( Chamberlin, 1919) described from the Tuamotu Islands ( 18°47′ S, 141°35′ W), and they are so similar that some Eastern Pacific records might represent this new species. After the key above, their main differences rely on the inner structure of the outer paleae, the angle formed by their tips, and the number of inner paleae. In L. mariae , outer paleae are solid, non-annulate, their tips bend at about 140–150°, and there are 14 pairs of inner paleae, whereas in L. nesiotes they are annulate internally, their tips are bent at about 120°, and there are 17 pairs of inner paleae.

Chamberlin (1919) included some other details that might be relevant. For example, in his specimens being up to 32 mm long, he noted that opercular paleae, inner and outer, had annulated cores ( Chamberlin 1919: 492: “cross-striate”), 5–7 chaetae in parathoracic parapodia, 17–19 pairs of branchiae, and dorsal hooks are completely covered by a fleshy depressed lobe matching hook’s shape ( Chamberlin 1919: 491, pl. 75 fig. 7). As indicated above, these features are size-dependent and of limited use for diagnostic purposes. On the other hand, he noted the median organ: “just in front of the nuchal hooks in the depression between the two opercular lobes is a long unpaired cirrus with a dark tip” ( Chamberlin 1919: 491). Capa et al. (2015: 197, table 1) noted it can be tapered, blunt (as in L. giardi ( M’Intosh, 1885) or L. wambiri Hutchings et al. 2012 ), or cylindrical truncate (in their L. nasutus ). The shape could be diagnostic as it seems truncate ones are cylindrical, whereas tapered ones are triangular in cross section; regretfully, there are no details about their shape, and their presence has been indicated for 8 out of 19 species compiled by Hutchings et al. (2012: 25, table 2).

Key to the species of Lygdamis Kinberg, 1867

(data from Hutchings et al. 2012; dos Santos et al. 2014; Capa et al. 2015)

1. Outer paleae smooth ......................................................................................................................... 2 – Outer paleae rugose, aristate ........................................................................................................... 21

2. Outer paleae of a single type............................................................................................................ 3 – Outer paleae of two types, thick aristate and thinner, tapered, about 20 per side; inner paleae straight, tapered, blunt, about 20 per side ..................... L. japonicus Nishi & Kirtley, 1999 (Amakusa, Japa)

3. Outer paleae with tips straight ......................................................................................................... 4 – Outer paleae curved, or with curved tips ........................................................................................ 12

4. Outer paleae sharp, non-aristate ....................................................................................................... 5 – Outer paleae aristate ......................................................................................................................... 8

5. Inner paleae smooth .......................................................................................................................... 6 – Inner paleae subdistally rugose, tips blunt, 10–14 per side; outer paleae 16–20 per side (body 12– 43 mm long) ...................................................................... L. giardi ( M’Intosh, 1885) ( SE Australia)

6. Inner paleae tapered, blunt ................................................................................................................ 7 – Inner paleae with wide tips, 30–36 per side; nuchal hooks tapered, tip sharp, wide; outer paleae 42–44 per side (body 15–20 mm long) ................................................................. L. augeneri Kirtley, 1994

7. Operculum with 25–30 marginal papillae per side (outer paleae 37–55 per side; inner paleae 16–19 per side); nuchal hooks tapered, tip sharp, thin (body 22–60 mm long) ............................................ ........................................................................................ L. giardi sensu Okuda 1938 ( Osaka, Japan)

– Operculum with 14–16 marginal papillae per side; nuchal hooks unknown (body 25 mm long) ...... ..................................................................................... L. gilchristi (McIntosh, 1924) ( South Africa)

8. Inner paleae smooth, non-annulated ................................................................................................. 9 – Inner paleae annulated, tips blunt, 10 per side; outer paleae 20 per side (body 30 mm long)............. ................................................................................................ L. bhaudi Kirtley, 1994 ( Madagascar)

9. Nuchal hooks with tips wide, blunt; outer paleae tapered, aristae long ......................................... 10 – Nuchal hooks with tips narrow, sharp; outer paleae widened medially, aristae short, 34–45 per side; inner paleae 11 per side (body 130 mm long) ............................... L. muratus Allen, 1904 ( England)

10. Operculum with less than 30 paleae per side ...................................................................................11 – Operculum with 50–60 outer, and 18–20 inner paleae per side (body 13 mm long) .......................... ................................................................... L. splendidus Lechapt & Kirtley, 1994 ( New Caledonia)

11. Operculum with 25 outer, and 10 inner paleae per side (body 11 mm long) ...................................... ................................................................................................. L. indicus Kinberg, 1867 ( Indonesia) – Operculum with 18 outer, and 7 inner paleae per side (body 30–43 mm long) ................................. ........................... L. nasutus Capa, Faroni-Perez & Hutchings, 2015 (Great Barrier Reef, Australia)

12. Outer paleae non-aristate ................................................................................................................ 13 – Outer paleae aristate ....................................................................................................................... 17

13. Outer paleae slightly curved; nuchal hooks tapered ....................................................................... 14 – Outer paleae markedly curved, 19–20 per side; nuchal hooks medially constricted, tip directed laterally at 90° from shaft (body 50 mm long) ................. L. gibbsi Kirtley, 1994 ( Solomon Islands)

14. Nuchal hooks tips bent ventrally .................................................................................................... 15 – Nuchal hooks tips directed laterally, not bent ventrally; operculum with 14–21 outer, and 9–14 inner paleae per side (body 95 mm long) .......... L. wirtzi Nishi & Núñez, 1999 ( Madeira, Canary Islands)

15. Outer paleae with tips wide, blunt, 25–32 per side; inner paleae 12–16 per side (body 28 mm long) ............................................................... L. curvatus ( Johansson, 1922) (Bonin Islands, Japan) – Outer paleae with tips narrow, tapered; nuchal hooks tapered, tips sharp, narrow ........................ 16

16. Inner paleae medially annulated, 16 per side; outer paleae 34 per side .............................................. ..................................................................................... L. malagasiensis Kirtley, 1994 ( Madagascar)

– Inner paleae smooth, 12 per side; outer paleae 15 per side (body 16 mm long) ................................ ................................................................................................ L. ehlersi ( Caullery, 1913) ( Indonesia)

17. Nuchal hooks with tips sharp .......................................................................................................... 18 – Nuchal hooks with tips blunt, wide; operculum with 28 outer, and 12 inner paleae per side (body 92–102 mm long) ................ L. rayrobersti Kirtley, 1994 (Florida) (dos Santos et al. 2014) ( Brazil)

18. Nuchal hooks tapered ..................................................................................................................... 19 – Nuchal hooks subdistally widened; outer paleae with aristae directed upwards, 25 per side; inner paleae 16 per side (body 45 mm long) ....................................... L. dayi Kirtley, 1994 ( South Africa)

19. Nuchal hooks tips short, narrow; outer paleae with tips bent about 90° ............................................ ................................................................................................. L. laevispinis ( Grube, 1870) ( Samoa) – Nuchal hooks tips long, wide .......................................................................................................... 20

20. Outer paleae subdistally annulate, with tips bent about 120°, 25–32 per side; inner paleae 12–16 per side; operculum with 12–15 marginal papillae ( 32 mm long) ............................................................ ............................................................................. L. nesiotes ( Chamberlin, 1919) (Tuamotu Islands)

– Outer paleae solid, not annulate, with tips bent 140°–150°, 34 (15–56) per side; inner paleae 14 (6–22) per side; operculum with 14 (8–18) marginal papillae ( 12–52 mm long) .............................. ................................................................................................. L. mariae sp. nov. ( Clipperton Island)

21. Outer paleae curved (34); inner paleae sharp (27) (ant. fragm. 23 mm long) .................................... .................................................................................. L. robinsi Jeldes & Lefevre, 1959 (off Angola) – Outer paleae straight ....................................................................................................................... 22

22. Inner paleae blunt ........................................................................................................................... 23 – Inner paleae sharp, 12 per side; outer paleae with about 30 paleae per side; outer paleae 27–29 per side (body 14 mm long) .......... L. wambiri Hutchings, Capa & Peart, 2012 ( Queensland, Australia)

23. Outer paleae with very long tip; inner paleae with tip slightly falcate (body 5.5 mm long) .............. ................................................................................. L. pechi Chávez-López, 2022 (Gulf of Mexico)

– Outer paleae with short tip; inner paleae with tip straight (body 10–40 mm long) ............................ ........................................................................................... L. kirkegaardi Kirtley, 1994 (off Liberia)

Remarks

Hartman (1967: 150) recorded an undescribed species from sediments at depths of 3678–3803 m in the Drake Passage, Antarctica. She indicated the operculum had 16 smooth outer paleae, and 3–4 inner ones per side, and that the nuchal hooks were “flat, curved at right angles to the shaft, and distally expanded.” The species was listed by Achari (1974: 50, table 1) as belonging to Lygdamis , but it was transferred to Tetreres and described as T. maririceae by Kirtley (1994: 194), although he did not cite Hartman’s record. This explains why it was excluded from the key above. On the other hand, the first introduction of the name Tetreres muratus var. gilchristi by McIntosh has been cited with three different years. Kirtley (1994: 127) gives 1922, Hartman (1959: 476) gives 1924, which is the correct one and followed by WoRMS ( Read & Fauchald 2021), and Day (1967: 677) gives 1925 which refers to the second publication, with illustrations, of the preceding one made one year before. On the other hand, because morphological features are size-dependent in L. mariae sp. nov., the known size or size range for each species has been included in the key to help identify specimens, because size range might differ between similar species.