Ophiopyrgus hainesae, O’Hara & Thuy, 2025

O’Hara, Timothy D. & Thuy, Ben, 2025, Seamount ophiuroids from the High Seas of the western Indian Ocean, Zootaxa 5718 (1), pp. 1-88 : 20-24

Ophiopyrgus hainesae sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:

Fig. 6–7

TYPE LOCALITY. Walters shoal, Plaine Sud, 33° 48.82´S, 44° 5.9699´E to 33° 51.8´S, 44° 4.72´E, 1539–1615 m.

TYPE MATERIAL. — MD208 : stn CP4913, Walters shoal, Plaine Sud, 33° 48.82´S, 44° 5.9699´E to 33° 51.8´S, 44° 4.72´E, 1539–1615 m, 11/5/2017, holotype: 1 ( MNHN IE.2023.4001); paratypes: 4 ( MNHN IE.2016.1341) ( DNA code= IE.2023.1341); paratypes: 184 ( MNHN IE.2016.1376) .

OTHER STUDY MATERIAL. — MD208 : stn CP4914, Walters shoal, Plaine Sud , 33° 51.1´S, 44° 4.8999´E to 33° 54.73´S, 44° 3.2199´E, 1598–1714 m, 11/5/2017: 194 ( MNHN IE.2016.1371) ( DNA code= IE.2016.1371) . — MD208 : stn CP4917, Walters Shoal, Plaine Nord-Ouest, 32° 54.9´S, 43° 23.8499´E to 32° 55.18´S, 43° 27.0001´E, 1375– 1296 m, 13/5/2017: 49 ( MNHN IE.2013.17148) ( DNA code= IE.2013.17148) . — MD208 : stn CP4918, Walters Shoal, Plaine Nord-Ouest, 32° 57.8´S, 43° 24.7´E to 32° 57.86´S, 43° 27.0499´E, 1356– 1295 m, 14/5/2017: 7 ( MNHN IE.2013.17156) . — MD208 : stn CP4920, Walters Shoal, Plaine Nord-Ouest, 32° 52.01´S, 43° 26.6899´E to 32° 51.99´S, 43° 30.9599´E, 1293– 1210 m, 14/5/2017: 1 ( MNHN IE.2013.17162) .

COMPARATIVE MATERIAL EXAMINED. Amphiophiura bullata ( Lyman, 1878) : ME 79- 1/554, Brasilian Basin , 26° 34.7´S, 35° 12.7896´W to 26° 34.87´S, 35° 12.7896´W, 4485 m, 22/7/2009 , DZMB-HH 13473 ( DNA code= DZMB13473 ). Ophiopyrgoides trispinosus ( Koehler, 1904) :IN2017 _ V03 /128, Coral Sea CMR, 23°37.872´S, 154° 39.582´E to 23° 39.54´S, 154° 38.628´E, 1770– 1761 m, 13/6/2017 , MV F239743 ( DNA code= MVF239743 ). IN2021 _ V04 /5, Christmas Island SE, 10° 34.22´S, 105° 41.376´E to 10° 33.791´S, 105° 41.6358´E, 643–997 m, 6/7/2021 , identified by O’Hara (2024b), MV F305516 ( DNA code=F305516). Ophiopyrgus bakeri ( McKnight, 2003a) : BIOPAPUA/CP3653, Ouest de la Nouvelle Hanovre , 2° 13´S, 150° 23´E, 680–700 m, 28/8/2010 , MNHN IE.2023.4071 ( DNA code=BP42). Ophiopyrgus cf. liberata BIOPAPUA /CP3672, Nord de Rabaul , 4° 4´S, 151° 50´E, 702–724 m, 24/9/2010 , MNHN IE.2007.2873 ( DNA code=BP44). Ophiopyrgus latro ( Koehler, 1904) : Siboga /251, Kapulauan Kai ( Kei Islands), 5° 28.4´S, 132° 0.2´E, 204 m, 8/12/1899, holotype , ZMA E2403 . BIOPAPUA/ DW3732, Au large des îles et récifs Lancasay, 8° 16´S, 150° 29´E, 340–358 m, 9/10/2010 , MNHN IE.2023.4072 ( DNA code=BP49). Ophiopyrgus liberata ( Koehler, 1904) : BIOPAPUA/CP3653, Ouest de la Nouvelle Hanovre , 2° 13´S, 150° 23´E, 680–700 m, 28/8/2010 , MNHN IE.2007.2820 ( DNA code=BP43). Ophiopyrgus prisca

( Koehler, 1904): SALOMON 2/CP2231, NW Choiseul, 6° 25´S, 156° 21´E, 1083–1100 m, 29/10/2004, MNHN ( DNA code=CP2231-1). Ophiopyrgus solida ( Lyman, 1878) : Challenger/192, Ki (Kei) Is, 5° 42´S, 132° 25´E, 239 m, 26/9/1874, holotype, BMNH 1882.12.23.44. EBISCO/CP2628, S Lansdowne, 21° 6´S, 160° 48.0002´E, 672–678 m, 21/10/2005, MNHN IE.2007.5420 ( DNA code=IE.2007.5420). IN2018_V06/094, Baseline_14, 44° 6.588´S, 146° 12.6´E to 44° 6.144´S, 146° 11.82´E, 965– 941 m, 6/12/2018, MV F271952 ( DNA code=F271952). Ophiopyrgus spatulifera ( Koehler, 1922a) : BIOPAPUA/CP3686, Monts sous-marins, sud de Manus Is., 3° 16´S, 147° 18´E, 964–1025 m, 28/9/2010, MNHN IE.2007.2817 ( DNA code=BP48).

Diagnosis. Dome-shaped disc with a tubercle-like centrodorsal plate, 5 primary plates, 2 dorsal and 1 ventral scale in each interradius, and D-shaped radial shields; all plates delimited by V-shaped furrows. Spiniform arm comb and genital papillae present. Oral shields 2x as long as wide with a narrower proximal lobe and squarish distal margin. Oral frame (including oral plates and adoral shields) sunken. Short tapering arms (to 4x dd) with contiguous DAPs, VAPs separate after first few proximal plates, 2 arm spines.

Description. Holotype 12 mm dd, disc dome-shaped, covered in a few large disc scales including a centrodorsal with a round pedicel and a dome-like tubercle, five hexagonal longer than wide primary plates with a peaked central point and a low ridge that extends from this peak to the centrodorsal, two plates in each interradius, a pentagonal proximal one and a tumid hexagonal distal one that forms the lateral edge to the disc, D-shaped radial shields with a straight edge radially, 2x as long as wide, all plates contiguous with a v-shaped furrow along their suture lines; ventral disc area covered by a single large square to rhomboid scale; arm comb comprises a series of separate spiniform papillae that articulate with a series of bosses on the abradial genital plate; these papillae continue along the bursal slit ventrally to half the disc radius, becoming square or slightly pointed, a few opposing papillae arising from a LAP occur under the dorsalmost end of the main arm comb series.

Oral shields teat-shaped with a squarish distal section, with straight to concave sides, and a narrower convex proximal lobe, slightly longer than wide; adoral shields slender, 4x as long as wide, meeting interradially and extending distally to 4/5 of the proximal lobe of the oral shield; exterior section of the oral plates parallelogramshaped, 4x as long as wide, contiguous interradially and extending to the end of the jaw slit; 8 conical oral papillae along each jaw side, interleaving with papillae on the opposing jaw; 2–3 abradial and 3–4 adradial tentacle scales around the 2nd oral tentacle pore, the distal adradial one enlarged.

Arms to 4x dd in length, rounded-triangular in cross section with a much narrower dorsal than ventral surface; first DAPs wider than long, elliptical, succeeding plates become smaller, kite-shaped to droplet-shaped, and separated by the 7th DAP; LAPs 2x as high as long, with a rounded dorsal angle, straight lateral sides and bent underneath to form the ventral surface; 1st VAP appears triangular in shape, with a bluntly rounded proximal edge and a straight to slightly convex distal edge, next plates 2x as wide as long, sometimes a small bare patch occurs between basal VAPs, becoming smaller and more separated by the 5th VAP, VAPs notably striated from the 2nd plate; 2 arm spines, 1/2 the length of a segment, situated lower down on the ventral section of the LAP, with the upper one occurring at the widest point of the arm and the lowest near the tentacle pore, the upper one developing a hook-like apex distally; 4–5 abradial and 2–3 adradial tentacle scales around basal arm pores, the distalmost adradial one much longer than wide, extending to midway of the abradial series, but which is not plate like nor confluent with the VAP (cf Ophiuroglypha ), by the 6th VAP there are 3 abradial and 1 rim-like adradial scale, distally only one abradial scale persists. Colour (live) pinkish-grey disc and light pink arms ( Fig. 6f ), (preserved) pale.

Paratype variations. The smallest specimen ( 6 mm dd) has a disc that is almost as high as wide, with tumid primaries and proximal interradial plates, and a comparatively large centrodorsal tubercle, the other specimens (to 11 mm dd) can be brown or white, and generally have a less prominent ridge between the centrodorsal and primary plates.

Paratype ossicles ( MNHN IE.2016.1376). Vertebrae zygospondylous ( Fig. 7a–e ) with prominent muscle fossae and podia basins, a long narrow zygosphene, and a prominent ventral groove; LAPs with dense stereom and simple arm spine-articulations with small circular pores for muscle attachment and nerve ( Fig. 7f–g ); dental plate 2.5 times as long as wide, with straight sides and 3 articulations for the teeth ( Fig. 7k ); centrodorsal tubercle with prominent perforations surrounded by small thorns ( Fig. 7l ); 1st VAP more complex that it appears from the external surface, with an extended rounded margin proximally and a squarish margin distally that sit underneath neighbouring plates ( Fig. 7o ); abradial genital plate nodulated along the dorsal edge, the nodules functioning as the base of the arm comb papillae ( Fig. 7r ); tentacle scales and arm spines with minute longitudinal grooves towards their apex ( Fig. 7s–t ).

Distribution. Walters Shoal ( 1210–1714 m).

Remarks. We have provisionally placed this new species in the genus Ophiopyrgus due to characters shared with the type species O. wyvillethomsoni Lyman, 1878 , including the raised centrodorsal plate, the few disc plates composed of the centrodorsal, primaries, radial shields and a series of 3 interradial plates extending from the primaries around the lateral side of the disc to the teat-shaped oral shield, the sunken oral frame, large basal tentacle pores with numerous scales, and the presence of a spiniform arm comb. However, O. wyvillethomsoni also has paedomorphic arms that are short, slender and rapidly tapering, with reduced VAPs and DAPs, and only a single arm spine, which makes comparison problematic. Unfortunately, we lack DNA sequences from O. wyvillethomsoni or the similar O. alcocki Koehler, 1897 (without a centrodorsal tubercle) and O. turritus Litvinova, 1984 (with a very tall centrodorsal tubercle), and future research could separate these species into a separate lineage.

In our phylogeny, O. hainesae is in the same clade as several other species of ‘ Amphiophiura ’, which are polyphyletic with respect to the type species of Amphiophiura , A. bullata . These include the species A. bakeri McKnight, 2003 , A. liberata ( Koehler, 1904) , A. latro ( Koehler, 1904) , A. prisca ( Koehler, 1904) , A. solida ( Lyman, 1878) and A. spatulifera Koehler, 1922a . All of these species share many of the characters of the genus Ophiopyrgus as outlined above and we transfer them all to his new genus.

Ophiopyrgus bakeri has a domed disc, with the same number of disc plates, but differs from our new species in lacking a centrodorsal tubercle and typically has 3 arm spines near the arm base. Ophiopyrgus liberata also has no centrodorsal tubercle but has very deep furrows between the dorsal disc plates, 4 arm spines, and oral shields that are 2x as long as wide with a square shaped distal section. Re-examination of the holotype of O. latro shows it has spinous or very granular disc scales that are deeply separated from neighbouring scales except for a ridge that connects the primary plates to each other and to the proximal interradial plates. This is different from the type description, which does not mention any spines or granules on the plates. In fact, Koehler (1930: 230) explicitly notes that the disc plates on O. latro have no trace of granules. Furthermore, there are only 2, basally 3 arm spines (not 4 as mentioned in the type description). However, the O. latro holotype is very similar to type description and figures of Amphiophiura pertusa Koehler, 1930 , which consequently we consider a synonym. Ophiopyrgus prisca has a relatively flat disc, with slightly raised circular areas in the centre of the centrodorsal and primary plates. It also differs from O. hainesae in appearing to lack an arm comb (although there can be some small spines on the basal LAP that may function as a comb), having 2–3 transverse series of ventral disc plates, and three long arm spines, the uppermost being almost as long as a segment. Ophiopyrgus solida is similar to O. bakeri except it has two rhomboidal ventral interradial plates that are parallel to each other, 2x as long as wide, and separated by a deep groove. Koehler (1930) distinguished his new species ‘Stegophiura’ turgida from O. solida on the basis of its shorter radial comb papillae, larger decalcified areas between basal VAPs and the lack of furrows between the disc plates. However, having compared the holotype of O. solida with the type photos of S. turgida we find no substantial difference in these characters, and also consider them to be synonyms. All the Challenger ( Lyman 1882), Siboga ( Koehler 1904) and Mortensen ( Koehler 1930) material of O. solida and O. turgida were collected near each other, around the Kei Islands Indonesia in 196– 348 m. Finally, O. spatulifera differs in having only two large interradial plates (only the proximal one is visible dorsally, the other is lateral), although it can have 1–2 smaller scales at the distolateral corners of the oral shield. The dorsal comb papillae are paddle-shaped, expanded near their apex.

There is also an undescribed species from Solomon Islands and Papua New Guinea (e.g., sample BP44) which is very similar to O. hainesae in having a tall tubercle on the centrodorsal, and similar patterns of disc plates, arm plates and arm spines. They differ from O. hainesae in having much deeper furrows around the disc plates (so that the plates appear like low tables), no connecting ridges, a raised central section on the lateral and ventral interradial disc plates, and concave margins to the distal section of the oral shields.

Other species referred to Ophiopyrgus do not seem related. Ophiopyrgus biocalae Vadon, 1991 has opposing rim-like tentacle scales similar to the type species of Ophiomastus , O. tegulitus Lyman, 1878 . Ophiopyrgus saccharatus Studer, 1882 , O. depressus Koehler, 1904 , O. trispinosus Koehler, 1904 were placed by H.L. Clark in a separate genus Ophiopyroides , characterised by the very large oral shield that takes up most of the ventral disc surface. Our DNA evidence supports this decision, as our samples of O. trispinosus are divergent from both the hainesae and bullata clades.

Etymology. Named after Maggie Haines, who sequenced many of the ophiuroids for this project.

Figures

FIGURE 6. Ophiopyrgus hainesae sp. nov. holotype MNHN IE.2023.4001 (a) dorsal view, (b) dorsal view enlarged, (c) arm base, lateral view, (d) dorsolateral view, (e) ventral view. (f) Ship-board photo of MD208 catch CP4914, with the species: Oh = Ophiopyrgus hainesae, Oa = Ophioplinthus abyssorum, Om = Ophiomyces delata, Sw = Stegophiura waltersi.

FIGURE 7. Ophiopyrgus hainesae sp. nov. paratype MNHN IE.2016.1376 (a) paired vertebrae, dorsal view, (b) paired vertebrae, lateral view, (c) vertebra, proximal view, (d) vertebra, distal view, (e) basal vertebra, proximal view, (f) lateral arm plate, ventral view, (g) lateral arm plate, lateral view, (h) oral plate, (i) ventral disc plate, (j) dorsal arm plate, (k) dental plate, (l) centrodorsal plate and tubercle, (m) oral shield, (n) second ventral arm plate, (o) first ventral arm plate, (p–q) opposite faces of adradial genital plate, (r) abradial plate with arm comb articulations on the upper right, (s) tentacle scale, (t) arm spine.