Nephtyidae, Grube, 1850

Kuş, Sevgi, Kurt, Güley & Çinar, Melih Ertan, 2021, Nephtyidae (Annelida: Polychaeta) from the Sea of Marmara and Black Sea, with descriptions of two new species, Zootaxa 5060 (2), pp. 183-214 : 185-186

Key to species of Nephtyidae from the Sea of Marmara and Black Sea

The main distinctive characters used in the key are the shape of the parapodial lamellae, the shape of acicular lobes and the chaetae types. Although there is some doubt about the existance of Inermonephtys foretmontardoi Ravara, Cunha & Pleijel, 2010 , Nephtys caeca (Fabricius, 1780) , N. ciliata (Müller, 1788) , N. hystricis McIntosh, 1900 , N. longosetosa Örsted, 1842 and N. paradoxa Malm, 1874 in the Sea of Marmara and the Black Sea, they are included in the key. The information included in the key is based on previous works that studied type material of these species (especially Ravara et. al. 2010; Dnestrovskaya 2020). Also it is thought that the new Inermonephtys species found in this study was previously designated as I. foretmontardoi in the region.

1. Prostomium without antennae.......................................................Genus Inermonephtys … 2

- Prostomium with antennae............................................................................. 3

2. Branchiae start at chaetiger 3–13, palps digitiform with cushion-like base, barred chaetae present in preacicular position of parapodia................................................................................ I. turcica n. sp.

- Branchiae start at chaetiger 3–4, palps small, cirriform without cushion-like base, barred chaetae absent.............................................................................. I. foretmontardoi Ravara, Cunha & Pleijel, 2010

3. Branchiae absent, notopodia of first chaetiger with dentate chaetae................................................................................................ Genus Micronephthys … M. longicornis ( Perejaslavtseva, 1891)

- Branchiae well developed, recurved.........................................................Genus Nephtys … 4

4. Geniculate chaetae present.............................................................................. 5

- Geniculate chaetae absent............................................................................... 6

5. Prostomium subpentagonal, spatula-shaped; ventral cirri of first chaetiger conical, almost longer than antennae and palps, acicular lobes unequally bilobed in anterior and median chaetigers, up to 10–15 geniculate chaetae...................................................................................................... N. cirrosa Ehlers, 1868

- Prostomium subrectangular, ventral cirri of first chaetiger digitiform, clearly shorter than antennae and palps; acicular lobes conical throughout the body, up to 4 geniculate chaetae.................................... Nephtys sinopensis n. sp.

6. Acicular lobes conical................................................................................. 7

- Acicular lobes rounded or bilobed...................................................................... 10

7. Branchiae start at chaetiger 4–6, neuropodial postchaetal lamellae more than twice as long as the notopodial postchaetal lamellae............................................................................................. 8

- Branchiae start at chaetiger 5–11, neuropodial postchaetal lamellae as long as the notopodial postchaetal lamellae......... 9

8. Branchiae start at chaetiger 4, acicular lobes without prominent papilliform outgrouth, rugose area near acicular lobes in anterior and median chaetigers.................................................. N. kersivalensis McIntosh, 1908

- Branchiae start at chaetiger 4–6, acicular lobes with prominent papilliform outgrouth.................................................................................................... N. hombergii Savigny in Lamarck, 1818

9. Branchiae start at chaetigers 8–11 (usually chaetiger 9–10); prechaetal lamellae rounded throughout the whole body...................................................................................... N. incisa Malmgren, 1865

- Branchiae start at chaetigers 5–7, usually at chaetiger 6; prechaetal lamellae of middle chaetigers distinctly bilobed...................................................................................... N. hystricis McIntosh, 1900

10. Postchaetal lamellae more than twice as long as acicular lobes; branchiae start at chaetigers 3–5 (usually chaetiger 3 or 4), to near posterior end.................................................................................... 11

- Postchaetal lamellae equal in size or slightly shorter than acicular lobes; branchiae start at chaetigers 7–14, reduced in posterior chaetigers.......................................................................................... 12

11. Branchiae start at chaetiger 4 (rarely 5); in middle chaetigers postchaetal lamellae more than twice as long as acicular lobes................................................................................. N. caeca (Fabricius, 1780)

- Branchiae start at chaetiger 3; notopodial postchaetal lamellae of median and posterior chaetigers much shorter than acicular lobes in neuropodia.............................................................. N. longosetosa Örsted, 1842

12. Branchiae start at chaetigers 7–11; acicular lobes of anterior and middle chaetigers distinctly bilobed.................................................................................................... N. ciliata (Müller, 1788)

- Branchiae start at chaetigers 9–14; acicular lobes rounded in anterior and median parapodia, conical in posterior parapodia.................................................................................. N. paradoxa Malm, 1874