Nogrobs de Montfort, 1808

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 68-69

25. Nogrobs de Montfort, 1808

( Fig. 31)

Type-species: Nogrobs vermicularis de Montfort, 1808 (a fossil taxon)

Number of (Recent) species: 1

Tube free, white, sinistrally coiled, initially cylindrical, then prismatic (quadrangular in cross-section), finally with short cylindrical straight distal part. Collar like rings and granular overlay absent. Operculum inverse cone (ampulla) with chitinous endplate and central depression. Peduncle pinnulated, without distal wings, with outer groove distally, with or without constriction beneath ampulla; inserted as second right radiole, up to 3 times as wide as other radioles. Pseudoperculum absent. Arrangement of radioles semi-circular, up to 8 per lobe. Inter-radiolar membrane, branchial eyes, and stylodes absent. Mouth palps absent. 4–6 thoracic chaetigerous segments. Collar non-lobed with entire edge, no clear separation towards thoracic membranes that end at second chaetiger. No apron, no tonguelets. Collar chaetae limbate ( Fig. 31A). Apomatus chaetae absent. Thoracic uncini saw-to-rasp-shaped with numerous teeth (> 12) in profile, 2–3 teeth per row (dental formula P:3:3:3:2:2:1:1:1:1:1:1:1:1); anterior peg gouged ( Pomatoceros type) ( Fig. 31B). Abdominal chaetae short, with flat triangular denticulate blade ( Fig. 31D). Thoracic triangular depression absent. Abdominal uncini similar to thoracic ones ( Fig. 31C). Achaetous anterior abdominal zone absent. Long posterior capillary chaetae absent. Posterior glandular pad absent.

Remarks. The diagnosis above is based on the description of the only Recent species thus far described - from specimens collected at depths of 1846–1900 m off the Azores. Topotypical material from 2440 m is present in the collections of the ZMA (V.Pol. 3906, presented by H. Zibrowius), additional material from the Central Atlantic was mentioned by Hartman & Fauchald (1971), they, however, counted 4 thoracic chaetigers only. A possible second undescribed species was found at 4124 m south-east off the Galapagos Islands (ZMA V.Pol. 3859). Zibrowius (pers. comm.) suspects a total of 4 different species, partly with not coiled quadrangular tubes.

Jäger (2004) synonymized the Recent genus Spirodiscus Fauvel, 1909 with the Fossil Nogrobs de Montfort, 1808 . Jäger also suggested that the Recent Bathyditrupa hovei might belong to the subgenus Nogrobs (Tetraditrupa) Regenhardt, 1961 , without further argumentation.

Nogrobs grimaldii ( Fauvel, 1909) , Central Atlantic , off Azores; bathyal, abyssal .