Glandulospio, Bick, Andreas, Guggolz, Theresa & Götting, Miriam, 2014

Bick, Andreas, Guggolz, Theresa & Götting, Miriam, 2014, Spionidae (Polychaeta: Canalipalpata: Spionida) from seamounts in the NE Atlantic, Zootaxa 3786 (3), pp. 201-245 : 224-225

Glandulospio gen. nov.

(Figures 11–14)

Type species: Glandulospio orestes sp. nov.

Type locality: NE Atlantic Ocean, Little Meteor Seamount: 29°38.19’N 028°59.07’W, station 632, depth 271.7 m.

Diagnosis. Anterolateral horns arising subanteriorly from prostomial margin, posterior part of prostomium extendend into short caruncle terminating at the end of chaetiger 1, with inconspicuous elevation at posterior end; occipital antenna lacking (Figures 11A–B, 12A, 13). Nuchal organs with two pairs of ciliary bands (Figures 11A, 12A–B, 13A left), continue as metameric double-paired ciliary bands (=metameric dorsal ciliated organs) between transversal ciliated bands of consecutive segments (Figures 11A, 12A). Branchiae present from chaetiger 1 (Figures 11A–B, 12A, 14A,). Large glandular organs present in chaetigers of the middle body region (chaetigers 5– 10) (Figure 12E–G). Neuropodial hooded hooks with pair of apical teeth present in posterior chaetigers (Figures 11C–D, 12C–D).

Etymology. The generic name is derived from the Latin “ glandula ” ~ “ gland” and “ spio ” ~ “ sea nymph”. It refers to the presence of large glandular organs in middle body segments, a conspicuous character of this taxon. Gender. Feminine.

Composition. One currently known species belongs to this new genus: Glandulospio orestes gen. et sp. nov. (this paper).

Remarks. Glandulospio gen. nov. is monotypic, with G. orestes gen. et sp. nov. being the only representative. The most conspicuous character of the new genus is certainly the presence of anterolateral horns which arise subanteriorly from the prostomial margin. The anterior and middle body region (defined by the absence of hooks in the neuropodia) seems very solid or compact; this is due to the presence of large glandular organs inside chaetigers 5–10. These glandular organs can often be detected through the epidermis if the specimen is placed in glycerin and viewed from the ventral side using a light microscope. Histological examination of course more easily reveals the presence of the glandular organs. Concerning the branchiae their strong difference in size along the body (comparing the long branchiae on chaetigers 3–6 (7) and branchiae before and beyond this region) stands out. Determining the relationship of the new genus with other taxa within the Spionidae is difficult. The prostomial shape including the presence of anterior or anterolateral horns or a deep anterior incision is also not rare within Spionidae ( Rhynchospio , Malacoceros , Scolecolepides , Glyphochaeta , Pygospiopsis , Lindaspio , Atherospio , Spiophanes , Microspio , etc.) but certainly requires a detailed review of this character for all taxa. The same can be addressed to the shape of nuchal organs and hook morphology. Large parapodial glands associated with the neuropodia are for example also present in Spiophanes or Glyphochaeta , but do not really imply a close phylogenetic relationship to these morphologically well-defined genera. The placement of the new genus within Spionidae has to remain uncertain until a thorough phylogenetic analysis of Spionidae is undertaken, and also additional genetic data become available. For example, the presence of prostomial horns in combination with the presence of branchiae from chaetiger 1 (as here reported for Glandulospio gen. nov.) has only been defined as generic characters for Malacoceros and Scolecolepides . However, other important characters as the type of nuchal organs and metameric dorsal ciliated organs, the morphology of branchiae, the occurrence of hooks in neuro- and notopodia, or the presence of large glands are either described differently, are unknown or are not included in the generic descriptions of Malacoceros and Scolecolepides . For the species M. fuliginosus ( Claparéde, 1870) genetic information on 18S rDNA was available from Genbank and the species selected as a representative of the genus to calculate the genetic distance between Glandulospio gen. nov. and Malacoceros (see also results in the chapter Molecular data in the present paper). According to this Glandulospio gen. nov. is clearly distinct.