taxonID	type	description	language	source
4414FDCB02A3515D9877ED37DBE3134E.taxon	type_taxon	Type species. Melinnopsis atlantica McIntosh, 1885 (type lodged at the Natural History Museum in London U. K., catalogue number 1885.12.1.330). Type locality off Chesapeake Bay, NW Atlantic, 3109 m.	en	Gunton, Laetitia M., Serpell-Stevens, Amanda, Riaz, Kashaf, Horton, Tammy (2025): A new species of Melinnopsis (Annelida, Melinnidae) from the Porcupine Abyssal Plain, northeast Atlantic. ZooKeys 1265: 1-23, DOI: 10.3897/zookeys.1265.171206
510576F5F371529C9ECB11F144D84A1B.taxon	description	Description. (based on holotype NHMUK ANEA 2025.3262) Holotype 35 mm length for more than 25 chaetigers, widest at post-branchial region 2 mm, thereafter gradually tapering to abdomen (1 mm width) (Fig. 3 A). Thorax with 16 or 17 chaetigers (lower thorax damaged so exact number of chaetigers uncertain). Neurochaetae as small acicular spines on segments II – V and uncini on remaining> 21 chaetigers. Prostomium with well-defined anterior and posterior sections separated by a pair of deep transverse nuchal slits meeting mid-dorsally (Fig. 3 D). Anterior part of prostomium whole, without any distinct lobes, and with a slightly raised lip. No eyespots or pigmented glandular bands present. No speckled pigment on anterior part of prostomium. Segment I continued ventrally forming lower margin of mouth with no crenulations on the ventral side (Fig. 3 B). Buccal tentacles in holotype missing, only one large stump remaining. Lateral wings of anterior body between prostomium and segment V slightly arched, peak approx. segment IV (Figs 3 E, 4 B). Segment I collar-like, laterally and ventrally encompassing head region. Branchiae emerging together on dorsal branchial ridge at level of segment II, arranged in two basally fused groups of four, three branchiae in front and one situated slightly behind (towards the anterior) (Figs 4 A, 5 A), the latter being the longest pair. Inner- and anteriormost branchia of each group completely separate, not joined by membrane. Branchiae in cross-section circular to slightly flattened smooth with central groove, gently tapering to filiform tips. Post-branchial dorsal membrane inconspicuous (Fig. 5 A). Post-branchial hooks absent. Segmentation visible dorsally in post-branchial area. No visible nephridial papillae. Notochaetae from segment IV, neurochaetae from segment II (Figs 4 B, 5 B). Capillary notochaetae starting from segment IV present in 12 or 13 thoracic chaetigers (lower thorax damaged exact number of chaetigers uncertain). Chaetiger 3 (segment IV) with few fine notochaetal capillaries and chaetiger 4 (segment V) with more abundant fine notochaeta arising from small slightly projecting notopodia (Fig. 5 B). Short cylindrical notopodia with thicker capillaries evident from chaetiger 5. Notochaetae arranged in double rows, those of anterior rows shorter. Rudimental abdominal notopodia missing. No small, rounded projections, evident in notopodial positions, no cilia observed. Neurochaetae as small acicular spines with lanceolate tips on segments II – V. Neuropodial uncini from chaetiger 5 (segment VI) (Fig. 5 B), present in 12 thoracic uncinigers and abdominal chaetigers. Holotype incomplete with ~ 15 abdominal uncinigers. Thoracic uncini emerging subdistally on short flaps from chaetigers 5 to approximately chaetiger 11 (Figs 3 F, 5 C). Abdominal uncini mostly missing in holotype but arranged on narrow lappets (Fig. 5 E). Uncini of thoracic uncinigers with three teeth (two small, one larger) in one vertical row over rostral tooth, subrostral process and basal prow (Figs 3 G, 5 D). Thoracic uncini in a single line with ~ 70 uncini (Fig. 5 C). Abdominal uncini in a single line with ~ 16 uncini (Fig. 5 E). Pygidium missing in holotype. Methyl blue staining pattern. Use of methyl blue in holotype reveals weak staining of prostomium. Posterior section of prostomium with speckled staining (Fig. 3 B). Strong staining transversely on segments I – IV (Fig. 3 A). Branchiae very lightly speckled. No clear lateral staining. Strong staining of ~ 13 or 14 ventral shields, staining strong in anterior section of ventral shield, light staining of posterior section of shield. This pattern is more defined towards the posterior of the worm. Shields do not cover entire ventral surface of the segment, stopping short at the uncini (Fig. 3 B). Tube. Missing in holotype.	en	Gunton, Laetitia M., Serpell-Stevens, Amanda, Riaz, Kashaf, Horton, Tammy (2025): A new species of Melinnopsis (Annelida, Melinnidae) from the Porcupine Abyssal Plain, northeast Atlantic. ZooKeys 1265: 1-23, DOI: 10.3897/zookeys.1265.171206
510576F5F371529C9ECB11F144D84A1B.taxon	distribution	Distribution. Porcupine Abyssal Plain, northeast Atlantic, 4843 – 4850 m.	en	Gunton, Laetitia M., Serpell-Stevens, Amanda, Riaz, Kashaf, Horton, Tammy (2025): A new species of Melinnopsis (Annelida, Melinnidae) from the Porcupine Abyssal Plain, northeast Atlantic. ZooKeys 1265: 1-23, DOI: 10.3897/zookeys.1265.171206
510576F5F371529C9ECB11F144D84A1B.taxon	etymology	Etymology. The new species is named for the second author’s son, Nathaniel Serpell-Stevens.	en	Gunton, Laetitia M., Serpell-Stevens, Amanda, Riaz, Kashaf, Horton, Tammy (2025): A new species of Melinnopsis (Annelida, Melinnidae) from the Porcupine Abyssal Plain, northeast Atlantic. ZooKeys 1265: 1-23, DOI: 10.3897/zookeys.1265.171206
