Paranerilla Jouin & Swedmark, 1965

Mendes, Samuel Lucas da Silva Delgado, Rodrigues, Jaqueline Carvalho & Rizzo, Alexandra E., 2024, A new species of Paranerilla Jouin & Swedmark, 1965 (Annelida: Polychaeta) from Brazil, European Journal of Taxonomy 943, pp. 144-153 : 147

Genus Paranerilla Jouin & Swedmark, 1965

Type species

Paranerilla limicola Jouin & Swedmark, 1965 , by original designation.

Diagnosis emendation (after Worsaae & Kristensen, 2003)

Seven chaetigers between prostomium and pygidium. Prostomium without appendages, only two lateral horns present. Compound chaetae and an acicular spine may be present. Dorsal and ventral ciliation well developed. Segment 1 with cirri fully developed. Cirri in following parapodia rudimentary. Two elongate pygidial cirri.

Remarks

Paranerilla Jouin & Swedmark, 1965 is one of the three Nerillidae genera which are found in deep waters ( Worsaae & Kristensen 2003). Paranerilla is monophyletic ( Worsaae 2005b) and currently has two accepted species: Paranerilla limicola Jouin & Swedmark, 1965 from Skagerrak, North Sea, and Paranerilla cilioscutata Worsaae & Kristensen, 2003 from Greenland, Arctic Ocean. They can be found in muddy sediments associated with diverse meiofaunal taxa from a range of 30 to 1216 meters deep ( Jouin & Swedmark 1965; Worsaae & Kristensen 2003). The ciliation pattern presented by these species is not only important to their locomotion and feeding behavior as mentioned but it is also used to infer the phylogenetic relations among the Nerillidae genera, and to distinguish the current valid species of Paranerilla ( Worsaae 2005b) .

The following characters are also important to distinguish species of Paranerilla : parapodial cirri shape on chaetiger 1 in comparison to other body segments, number of spiniger compound chaetae in chaetiger 1 in relation to other body segments, and pygidial cirri features ( Jouin & Swedmark 1965; Worsaae & Kristensen 2003). However, none of the already described species mentioned above presented an acicular chaeta emerging from any of their chaetal fascicles, based on their respective descriptions, P. schiavettii sp. nov. being the exception among them. This additional morphological feature may be used to separate species of Paranerilla in future descriptions, and we include it as an emendation on the genus diagnosis.