Marenzelleria undetermined

• Main Authors: Radashevsky, Vasily I., Pankova, Victoria V., Malyar, Vasily V., Cerca, José, Struck, Torsten H.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Annelida; Polychaeta; Spionida; Spionidae; Marenzelleria; Marenzelleria undetermined; Baffin; Nunavut
• Online Access: https://doi.org/10.5281/zenodo.5776893; http://treatment.plazi.org/id/4633878EFFADB04A4B83FF3063E56714

Marenzelleria sp. (Figs 2, 4–6) Material. Canada, Nunavut, Baffin Is., Koluktoo Bay, 3–21 m, 2018–2020, MIMB 40927, 40928, 42134–42138 (50 spec.). Complete information about this material is given in Table S 5. Description. Anterior fragments and complete juveniles 10–15 mm long, 0.3–0.8 mm wide for 57–88 chaetigers. Fine dark pigment usually scattered on dorsal side of prostomium and 1–2 anterior chaetigers (Fig. 4A–D). Prostomium anteriorly broadly rounded, usually with small incision on frontal margin (Fig. 4A–D), rarely entire. Two pairs of small red eyes arranged trapezoidally; lateral eyes situated anteriorly and set wider apart; occasionally eyes absent. Nuchal organs U-shaped ciliary bands, extending posteriorly to end of chaetiger 2, shorter in small individuals (Figs 4A–D, 5A). Chaetiger 1 well developed, with capillary chaetae and postchaetal lamellae in both rami; notochaetae as long as those on chaetiger 2, arranged in three distinct groups, comprising short anterior-row capillaries with wide limbation, slightly longer posterior-row capillaries with wide limbation, and long thin alimbate superior capillaries. Sabre chaetae in neuropodia from chaetiger 4 onwards in worms of all sizes (Fig. 5E). Hooded hooks in notopodia from chaetigers 24–40, in neuropodia from chaetigers 21−31 onwards (Fig. 5E, F); hooks bidentate with outer hood only and slightly curved shaft (Fig. 4E). Branchiae from chaetiger 1 on anterior half of body (Fig. 5C, D), fused to notopodial postchaetal lamellae at least basally on anterior chaetigers, with surfaces oriented perpendicular to body axis, with ciliation on inner and outer edges (Fig. 4A). Pygidium with up to five pairs of cirri, comprising one pair of short thick ventral cirri, and four pairs of long thin dorsal cirri; dorsal cirri fewer in small individuals (Fig. 5B). Remarks. Marenzelleria species have no unique morphological features and can be distinguished only by the maximum values of morphometric characteristics, such as the length of the nuchal organs, the ...