Prionospio Malmgren, 1867

Peixoto, Antônio João Malafaia & Paiva, Paulo Cesar De, 2019, New Prionospio and Laubieriellus (Annelida: Spionidae) species from Southeastern Brazil, Zootaxa 4577 (3), pp. 529-547 : 531-532

Prionospio Malmgren, 1867

Type species: Prionospio steenstrupi Malmgren, 1867

Diagnosis (emended from Blake et al. 2017): Prostomium anteriorly rounded or truncate, sometimes weakly incised, often with peaks, without frontal horns; subtriangular, rectangular or oval in shape, caruncle extending at least to chaetiger 1; eyespots present or absent; occipital antenna absent. Peristomium at least partially fused with chaetiger 1, often surrounding prostomium with free, flattened lateral wings. Parapodia of chaetiger 1 reduced; noto- and neuropodial lamellae largest in branchial region, reduced thereafter; notopodial lamellae often connected by low to high dorsal ridges or crests. Branchiae from chaetiger 2, chaetiger 3 or rarely absent. Branchiae limited to anterior chaetigers, 0–15 pairs, rarely more; branchiae all apinnate, all pinnate, or various combinations of both; pinnate branchiae with pinnules digitiform, not platelike; each branchia entirely free from dorsal lamella. Interparapodial pouches present or absent. Anterior chaetae limbate capillaries; posterior noto- and neuropodial hooded hooks present, bi-, tri-, or multidentate, with secondary hood. Neuropodial sabre chaetae present or absent. Pygidium with one long dorsomedial cirrus and two shorter ventrolateral lobes, all three sometimes fused.

Remarks: Blake et al.’s (2017) diagnosis was amended to include Prionospio solisi sp. nov. and Prionospio nonatoi sp. nov., which either lack branchiae or have only two pairs (see description and remarks for each species below). Changes in Blake et al.’s (2017) diagnosis have been highlighted in bold.

The Prionospio -complex represents one of the most morphologically diverse groups within the Spionidae and even within Prionospio sensu stricto, exhibiting remarkable branchial diversity, with many different arrangements. These different branchial arrangements were used in the past to erect other genera or subgenera within Prionospio ( Foster 1971) , such as Aquilaspio and Minuspio which are no longer considered as valid (e.g., Sigvaldadóttir 1998) by some authors and thus were synonymized with Prionospio , although such synonymy is not fully accepted and some researchers still consider Aquilaspio ( Zhou & Li 2009; Dagli & Çinar 2009; Dagli & Çinar 2011) and Minuspio ( Aguirrezabalaga & Ceberio 2005; Zhou & Li 2009; Dagli & Çinar 2009; Dagli & Çinar 2011; Dagli et al. 2011; Dagli 2013; Delgado-Blas & Díaz-Díaz 2013) as valid.

As for the species described in this work, despite bearing a branchial pattern (or lack of branchiae) that is similar to Aurospio , neither species could be placed in Aurospio , based on the lack of fusion of the branchiae to the notopodial lamellae (in Prionospio solisi sp. nov.) and the presence of a secondary hood on the hooded hooks.. Blake et al. (2017) noted that, over the past few years, several Prionospio species have been erroneously attributed to Aurospio . As further discussed in the Remarks section of each species, both species are morphologically similar to Prionospio . The placement of these species in Prionospio , however, should be treated as conservative, as we consider that the different branchial arrangements observed in both species do not justify the erection of a new taxon, neither within the Prionospio -complex nor within Prionospio sensu stricto.