Paranerilla schiavettii, Mendes & Rodrigues & Rizzo, 2024

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 : 147-151

publication ID

https://doi.org/ 10.5852/ejt.2024.943.2591

publication LSID

lsid:zoobank.org:pub:122E417A-0CD2-4CD5-910A-956D69F2F06F

DOI

https://doi.org/10.5281/zenodo.12692366

persistent identifier

https://treatment.plazi.org/id/1CA5BCBC-9EB7-4ECF-99B1-BD98565C9086

taxon LSID

lsid:zoobank.org:act:1CA5BCBC-9EB7-4ECF-99B1-BD98565C9086

treatment provided by

Plazi

scientific name

Paranerilla schiavettii
status

sp. nov.

Paranerilla schiavettii sp. nov.

urn:lsid:zoobank.org:act:1CA5BCBC-9EB7-4ECF-99B1-BD98565C9086

Figs 2–3 View Fig View Fig

Diagnosis

Specimens from grey to whitish color, with prostomium and segment 1 almost fused and about as long as each of the following segments. One acicular chaeta on noto- and one on neuropodia from chaetiger 3 to 7; 14 spiniger compound chaetae on chaetiger 1, 7–12 on chaetigers 3–7, both present as single pointed distal extensions following chaetal articulation. Prostomium, peristomium and entire dorsal and ventral body surfaces of segments 1–7 densely covered with cilia.

Etymology

The specific epithet ‘ schiavettii ’ was chosen to honor the professor and our friend Alexandre Schiavetti, for his important contributions to improve our scientific knowledge on marine ecology, especially marine protected areas in Brazil.

Type material

Holotype

BRAZIL – Santos basin • 1 complete spec.; 25º03′46.44″ S, 45º35′45.24″ W; depth 100 m; 22 Jun. 2021; UERJ 8904 . GoogleMaps

Paratype

BRAZIL – Santos basin • 8 specs without anal cirri; 26º09′24,84″ S, 47º12′59″ W; depth 100 m; 16 Jun. 2021; UERJ 8903 GoogleMaps .

Other material examined

BRAZIL – Santos basin • 2 specs; 27º01′18.8400″ S, 47º43′45.8400″ W; depth 100 m; 13 Jun. 2021; UERJ 8927 GoogleMaps 1 spec.; 23°29′12.8400″ S, 43°58′30.7200″ W; depth 75 m; 3 Jun. 2021; UERJ 8928 GoogleMaps 1 spec.; 24°05′20.0400″ S, 43°40′23.5200″ W; depth 150 m; UERJ 8929 GoogleMaps 5 specs; 29°09′25.200″ S, 47°13′01.4800″ W; depth 10 m; 15 Jun. 2021; UERJ 8930 GoogleMaps 1 spec.; 25°40′31.080″ S, 43°59′20.8″ W; depth 2169 m; 2 Jul. 2019; UERJ 8960 GoogleMaps .

Description

Holotype complete; measuring 980 μm long for 242 μm wide. Paratypes complete, measuring 319– 870 μm long for up to 200–316 μm wide. Grey to whitish specimens, consisting of prostomium, seven chaetigers ( Fig. 2A View Fig ) and pygidium with pair of terminal cirri ( Fig. 3E View Fig ). Maximum body width always at chaetiger 4 excluding parapodia ( Fig. 2A View Fig ). Prostomium with pair of lateral horns and almost fused to chaetiger 1 ( Fig. 2D View Fig ). Prostomium up to 36 μm long, 144 μm wide including lateral horns ( Fig. 3A View Fig ); maximum length of lateral horns up to 40 μm, measured along the posterior edge. Prostomium and chaetiger 1 together about as long as each of the following segments. All body segments similar in width and length, except for slight expansion on chaetiger 4 ( Fig. 2a View Fig ). Nuchal organs not observed.

Parapodia on chaetiger 1, usually about 2 × as long as length of following parapodia ( Fig. 2D View Fig ). Short cirri with strongly ciliated band on chaetiger 1 ( Fig. 2D View Fig ). Rudimentary cirri with distal cilia may be found on chaetigers 2–7, between dorsal and ventral chaetal bundles. Two pygidial cirri up to 132 μm long ( Fig. 3E View Fig ). One acicular spine on noto- and one on neuropodia of chaetigers 3–7 accompanying spinigers compound chaetae ( Fig. 3F View Fig ), one emerging ventrally to them on notopodia and another dorsally to them on neuropodia. Spiniger compound chaetae present as single pointed distal extension following chaetae articulation ( Fig. 2B View Fig ). Chaetiger 1 uniramous, bearing two chaetal fascicles ( Fig. 2D View Fig ), with maximum of 14 chaetae; segments 2–7 biramous, with one dorsal and ventral fascicles, comprising 7–12 chaetae each, highest number in chaetigers 3–5. Chaetae on chaetigers 1 and 7 longer than those of other chaetigers ( Fig. 3C View Fig ), but chaetae on chaetiger 7 slightly shorter than those on chaetiger 1 ( Fig. 3C View Fig ).

Prostomium, peristomium and entire dorsal and ventral body surfaces of chaetigers 1–7 densely covered by cilia, except in gaps between ciliated bands ( Fig. 3A View Fig ) and parapodial rami on body lateral surface and among chaetal fascicles ( Fig. 2C View Fig ). Dorsally, chaetiger 1 presenting dorsal ciliary plate followed posteriorly by three transverse ciliary bands ( Fig. 3A View Fig ). Ventrally, chaetiger 1 having ventral ciliary plate around mouth opening followed posteriorly by two ventral transverse ciliary bands ( Fig. 3D View Fig ). Chaetigers 2–7 with four transverse ciliary bands each both dorsally and ventrally.

Ecology

Santos Basin, Brazil. From a range of 75 to 2169 meters deep. The habitat is characterized predominantly by muddy sediments on the continental slope, but some specimens were found living in sandy sediments on the continental shelf.

Remarks

Despite their morphological differences, both P. schiavettii sp. nov. and the currently valid species present 7 chaetigers, two pygidial cirri, a well developed pattern of dorsal and ventral ciliation, chaetiger 1 with cirri fully developed and rudimentary cirri in following parapodia ( Jouin & Swedmark 1965; Worsaae & Kristensen 2003). The prostomium and chaetiger 1 present large ciliated areas and the following segments present small transverse bands in P. limicola , but are densely ciliated in P. cilioscutata and P. schiavettii ( Jouin & Swedmark 1965; Worsaae and Kristensen 2003). Both species present frontal horns, compound chaetae, chaetiger 1 with small cirri, and rudimentary cirri in all following chaetigers. Paranerilla limicola differs from P. cilioscutata not only in ciliation pattern but also on chaetal arrangement. Chaetiger 1 in P. limicola presents 13–17 chaetae, but P. cilioscutata and P. schiavettii present only 14 chaetae in the same chaetiger. On the other hand, in P. schiavettii and P. limicola , the chaetae on chaetiger 1 are longer in comparison to other chaetigers. Finally, the holotype of P. schiavettii presents a maximum body width at chaetiger 4, but this characteristic is variable among specimens of P. schiavettii , with chaetiger 4 commonly similar to other chaetigers in some paratypes.

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Family

Nerillidae

Genus

Paranerilla

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