A new genus and species of Polynoidae (Annelida: Polychaeta) from the Canary Islands, and update on taxa present in the Northeast Atlantic

. A new polynoid, Webbnesia maculata gen. et sp. nov., was discovered during benthic surveys conducted around the Canary Islands. Its generic characters (absence of cephalic peaks, ventrally inserted lateral antennae, reduced notopodium and chaetae all stout) place it close to Antinoe Kinberg, 1856, Hermadion Kinberg, 1856 and Malmgrenia McIntosh, 1874, but the combination is unique and justi ﬁ es the erection of a new genus. The new genus and species are described, ﬁ gured and discussed in detail. An updated list of taxa and an identi ﬁ cation key to all genera of Polynoinae Kinberg, 1856 sensu lato currently reported from the extended Northeast Atlantic are given.


Introduction
During benthic surveys conducted around the Canary Islands, several specimens of an unknown scale worm were discovered. A closer investigation revealed that they belong to an undescribed genus and species of Polynoidae Kinberg, 1856.
Due to the large number of species and genera (about 900 species and 167 genera, cf. Bonifácio & Menot 2019), the family is subdivided into several subfamilies, which have been controversially discussed in the past (Wehe 2006;Norlinder et al. 2012;among others). To date, members of the following subfamilies are reported from the extended Northeast Atlantic: Polynoinae Kinberg, 1856;Lepidonotinae Willey, 1902;Macellicephalinae Hartmann-Schröder, 1971; Lepidastheniinae Pettibone, 1989; Arctonoinae Hanley, 1989. As summarised by Wehe (2006) the distinguishing characters established by Hanley (1989) for Arctonoinae do not allow for an unambiguous subfamily classifi cation and several genera which were initially assigned to this subfamily have been subsequently moved to Polynoinae (for example Adyte Saint-Joseph, 1899, Subadyte Pettibone, 1969 andMalmgrenia McIntosh, 1874, see Barnich & Fiege 2001, 2003. Arctonoinae is currently under revision by one of us (RB) in collaboration with Robin Wilson (Museum Victoria, Melbourne, Australia). This revision is still at an early stage and it is not clear yet, if Arctonoinae can be maintained and if so, which genera will be assigned to this subfamily. In the current study, we therefore follow Barnich & Fiege (2003) and, for the time being, we include genera previously assigned to Arctonoinae in Polynoinae sensu lato.
The main distinguishing characters of the different subfamilies are: Macellicephalinae with median antenna absent or present and lateral antennae absent (subfamily recently revised by Bonifácio & Menot 2019).
Lepidastheniinae with median antenna present and lateral antennae inserted terminally; neuropodia deeply incised (i.e., acicular lobe of similar length than postchaetal lobe, both lobes prominent).
Polynoinae sensu lato with median antenna present and lateral antennae inserted ventrally or terminoventrally.
Due to the presence of a median antenna and lateral antennae being inserted ventrally, the new genus and species from the Canary Islands can be assigned to the subfamily Polynoinae. Currently, 24 genera and 77 species of Polynoinae sensu lato (incl. the new genus and species) are recognised in the area. Table 1 gives an updated list of taxa together with details on distribution, depth and references.
Below, we present a detailed morphological description and justifi cation for the new polynoid genus and species. We discuss and compare the diagnostic characters of the new genus (see also Tables 2 and  3) and we provide an updated identifi cation key to all genera of Polynoinae sensu lato found in the area. The material, being preserved in formaldehyde, is unfortunately not suitable for molecular analysis.
Preserved specimens were examined using Leica MS5 and Olympus SZX12 stereo microscopes and Leica DMLB (equipped with differential interference contrast), Nikon Eclipse 80i and Olympus BX41 compound light microscopes. Semi-permanent glycerine slides were used for morphological examination of parapodia, elytrae and chaetae.
Drawings were made using a camera lucida and complimented by digital photography. Digital images were captured with an OLYMPUS DP70 camera mounted on Leica DMLB and Olympus BX41 microscopes. The photographs were processed with the DP Controller and Combine ZM software.
The type specimens are deposited at the Museum of Natural Sciences of Tenerife (TFMC, holotype and paratypes) and at the Senckenberg Natural History Museum Frankfurt (SMF, paratype).

Diagnosis
BODY. Flattened dorsoventrally, short, with fewer than 40 segments, more or less covered by elytra dorsally.
CHAETAE. Notochaetae and neurochaetae stout, with rows of spines and entire tip.

Etymology
The genus name is a combination of the name Webb and the Greek word 'nes' (= 'island'); gender feminine. 'Webbnesia' refers to a new ecoregion defi ned by Freitas et al. (2019) and co-authored by one of us (JN) which includes the Canary, Savage and Madeira Islands.  Pettibone 1993;Bock et al. 2010 andBarnich et al. 2017) share the following diagnostic characters with Webbnesia gen. nov.: 15 pairs of elytra, fewer than 50 segments (i.e., short-bodied), cephalic peaks absent, noto-and neurochaetae all of same type, stout, without semi-lunar pockets.
Webbnesia and Hermadion have ventrally inserted lateral antennae, but the shape of their parapodia is different. The notopodium of Hermadion is prominent, nearly as long as the neuropodium, while the new genus is characterised by a minute, reduced notopodium (see Tables 2-3).
In Malmgrenia and Antinoe the parapodia are similar to those of Webbnesia, but the main difference is the insertion of the lateral antennae, which is ventral in Webbnesia and terminoventral in the two other genera.
Among the polynoid genera sharing the diagnostic characters listed above, the combination of ventrally inserted antennae and a reduced notopodium is unique and justifi es the erection of a new genus (see Table 2). PARAPODIA. With reduced notopodium and prominent neuropodium; neuropodium with minute (i.e., reduced) supra-acicular process, aciculum penetrating subdistally.
CHAETAE. Notochaetae stout with faint rows of spines and entire tip. Neurochaetae stout with distinct rows of spines and falcate, entire tip.

Etymology
The species epithet refers to the characteristic pigmented patches on the elytra, described by the Latin word 'maculatus' in its female form.  BODY. Flattened dorsoventrally, short, with 33 segments, dorsum covered by elytra (Fig. 3A); ovigerous female ( Fig. 4C-D).

Distribution and habitat
NE Atlantic, Canary Islands: E and S of Gran Canaria and S of Tenerife; in 22 to 60 m depth.
The substrate at the Tufía station is characterised by areas of fi ne sand and poorly consolidated maerl. The faunal composition is dominated by the polychaetes Paradoneis armata Glémarec, 1966 andAponuphis ornata (Fauvel, 1928)  At the Granadilla station the substrate is characterised by maerl and coarse sand. The faunal composition is dominated by the amphipod Animoceradocus semiserratus (Spence Bate, 1862) and the polychaetes Chone fi licaudata Southern, 1914 andAponuphis bilineata (Baird, 1870).
In order to allow for identifi cation of anterior fragments, the current key avoids, where possible, the use of numbers of elytra and segments as main distinguishing character.

Discussion
Webbnesia gen. nov. differs from all other polynoids by its unique combination of characters. With its short body (fewer than 50 segments), absence of cephalic peaks and all chaetae being stout, it is similar to Hermadion Kinberg, 1856, Antinoe Kinberg, 1856 and Malmgrenia McIntosh, 1874. However, as discussed above, it can be differentiated from Hermadion by its reduced notopodium, and from Malmgrenia and Antinoe by its ventrally inserted lateral antennae.
So far, no species attributed to Hermadion or Antinoe are reported from the Northeast Atlantic. The genus Hermadion is currently represented by one valid species, i.e., Hermadion magalhaensi Kinberg, 1856, which occurs only in Sub-antarctic waters (Bock et al. 2010). According to Read & Fauchald (2022b), six species of Antinoe are considered valid. The genus was only partly revised by Pettibone (1993) and included the type species A. microps Kinberg, 1856 (from the Southwest Atlantic) and A. uschakovi (Ibarzábal, 1988) from the Caribbean Sea. The generic attribution of the remaining four species still needs revising: Antinoe epitoca (Monro, 1930) is reported from the Southeast Atlantic and from the Southwest Pacifi c (see Monro 1930, Glasby et al. 2009), A. kermadecensis (McIntosh, 1885 and A. purpureus Knox, 1960 from the Southwest Pacifi c, and fi nally A. lactea Day, 1953from South Africa (see McIntosh 1885Knox 1960;Day 1953).
In the Northeast Atlantic Webbnesia maculata gen. et sp. nov. could be superfi cially confused with some species of Malmgrenia (see Barnich et al. 2017). However, the lateral antennae of the new species are inserted ventrally and not terminoventrally as defi ned for the genus Malmgrenia. Additionally, there is currently no other polynoid species known to have a neuropodium with a reduced supra-acicular process and neurochaetae being all stout with a simple, unidentate tip. All of this justifi es the erection of a new genus and species for these remarkable animals found in the waters around the Canary Islands.
With the key to genera (see above) and the list of valid species (see Table 1), we present here a fi rst update of genera and species for the entire Northeast Atlantic (incl. the Mediterranean Sea).