Perinereis, Kinberg, 1865, Kinberg, 1865

Villalobos-Guerrero, Tulio F., 2019, Redescription of two overlooked species of the Perinereis nuntia complex and morphological delimitation of P. nuntia (Savigny in Lamarck, 1818) from the Red Sea (Annelida, Nereididae), Zoosystema 41 (24), pp. 465-496 : 488-489

KEY TO SPECIES OF PERINEREIS NUNTIA COMPLEX (ADAPTED FROM Wilson & Glasby 1993, AND Glasby & Hsieh 2006)

This key includes all species regarded as members of the P. nuntia complex ( Wilson & Glasby 1993; Glasby & Hsieh 2006), and other species previously regarded as not valid or even excluded. Nevertheless, some species deserve considerations since the broadly different morphological features may suggest that some species belong to a distinct group, but the phylogenetic analysis of the complex would be needed to support this idea. Glasby & Hsieh (2006) already suggested P. akuna , P. caeruleis and P. rhombodonta as possibly not members of the P. nuntia complex by having pyramidal paragnaths on AVI and several rows of small cones separated from larger ones on AVII-VIII. However, P. caeruleis is strikingly different within the P. nuntia complex by also having a slight distal incision on the prostomium, posterior parapodia with papilliform dorsal cirrus inserted distally on an expanded dorsal ligule, short heterogomph falcigers with a much reduced serrated region throughout the body, and a large number of minute paragnaths on AIII to AVII-VIII. Also, P. maindroni Fauvel, 1943 has been considered as a member of the P. nuntia complex by having AVI with barshaped paragnaths in a transverse row. However, it is the only species within the complex bearing a notoriously elongated digitiform dorsal ligule in median parapodia, well-developed notopodial prechaetal and neuropodial postchaetal lobes, and a dorsal cirrus basally attached in all parapodia ( Fauvel 1943). Despite Glasby & Hsieh (2006) diagnosed the complex as lacking these lobes, they still recognized P. maindroni as a P. nuntia -like species.

1. Dorsal ligule elongated in median parapodia; notopodial prechaetal and neuropodial postchaetal lobes developed ............................................................................................................ P. maindroni Fauvel, 1943

— Dorsal ligule not elongated in all parapodia; notopodial prechaetal and neuropodial postchaetal lobes not developed .............................................................................................................................................. 2

2(1). Dorsal ligule broadly expanded in posterior parapodia; AVI with two arcs of paragnaths; AII without paragnaths; AV with more than 30 paragnaths; AVII-VIII with more than 200 paragnaths ............................. ..................................................................................................................... P. caeruleis ( Hoagland, 1921)

— Dorsal ligule of similar size in all parapodia, or barely uneven in posterior parapodia; AVI with single arc of paragnaths; AII with paragnaths; AV with less than 5 paragnaths; AVII-VIII with less than 199 paragnaths ........ 3

3(2). Homogomph spinigers present in subacicular fascicle of neuropodia; heterogomph spinigers absent ..... 4

— Homogomph spinigers absent in subacicular fascicle of neuropodia; heterogomph spinigers present at least from median chaetigers .......................................................................................................................... 5

4(3). Paragnaths absent on AVII-VIII ............................................................................. P. matthaii Aziz, 1938

— Paragnaths present on AVII-VIII .................................................. P. weijhouensis Wu, Sun & Yang, 1981

5(3). AVII-VIII with a band of large cones and a band of numerous minute cones ......................................... 6

— AVII-VIII without an additional band of minute cones ......................................................................... 7

6(5). AVI with pyramidal paragnaths; AVII-VIII with some paragnaths in rhomboidal arrangement; AIV without merged paragnaths ....................................................................... P. rhombodonta Wu, Sun & Yang, 1981

— AVI with shield-shaped bars; AVII-VIII with paragnaths in regular transverse arrangement; AIV with 2-4 merged paragnaths .......................................................................... P. akuna Wilson & Glasby, 1993

7(5). AIV with merged paragnaths ................................................................................................................. 8

— AIV without merged paragnaths (cones only) ...................................................................................... 10

8(7). AIV with more than 10 merged paragnaths; AIII with more than 40 cones. P. majungaensis Fauvel, 1921

— AIV with less than 5 merged paragnaths; AIII with less than 35 cones ................................................... 9

9(8). AVI with 8-18 paragnaths ........................................ P. vallata (Grube & Kröyer in Grube, 1858) , partim

— AVI with 2-4 paragnaths ......................................................................... P. viridis Glasby & Hsieh, 2006

10(7). Ridges of AVI distally separated from each other (AVI-V-VI patterns π-shaped; Fig. 1 D-L) ................. 11

— Ridges of AVI distally and sub-medially coalesced (AVI-V-VI pattern λ- shaped; Fig. 1 A-C) ................. 19

11(10). Ridges of AVI sub-medially markedly separated from each other (AVI-V-VI patterns ɔc-shaped or υ- shaped; Fig. 1 G-L) ........................................................................................................................................... 12

— Ridges of AVI sub-medially coalesced or nearly so (AVI-V-VI pattern χ- shaped; Fig. 1 D-F) ................ 14

12(11). AVI-V-VI with ɔc-shaped pattern (concave furrows; Fig. 1 J-L); dorsal cirri cirriform, long; AII with more than 17 paragnaths ............................................................................... P. shikueii Glasby & Hsieh, 2006

— AVI-V-VI with υ- shaped pattern (parallel furrows; Fig. 1 G-I); dorsal cirri digitiform, short in medial and posterior parapodia; AII with up to 10 paragnaths ............................................................................... 13

13(12). Heterogomph spinigers absent in few first anterior chaetigers; natatory parapodia of epitokous female with additional expanded lamella in median ligule, sharp projection in ventral ligule ....................................... ........................................................................................ P. larentukana (Grube in Peters, 1881) n. comb.

— Heterogomph spinigers present in all chaetigers; natatory parapodia of epitokous female lacking additional lamella in median ligule or projections in ventral ligule ............................... P. quatrefagesi ( Grube, 1878)

14(13). Dorsal cirrus about 1.5 times longer than dorsal ligule in anterior parapodia, increasing to 2-4 times its length posteriorly ................................................................................................................................. 15

— Dorsal cirrus not extending or only barely extending beyond end of dorsal ligule throughout ............. 17

15(14). AVI with very uneven-length bars (outermost longest) ........................... P. wilsoni Glasby & Hsieh, 2006

— AVI with short even-length bars (outermost only slightly longer if at all) ............................................. 16

16(15). AVII-VIII with less than 20-27 paragnaths, arranged in 1-2 transversal rows; AVI with 3-4 paragnaths; AIII with 6-10 paragnaths; AV with 1 paragnaths ................................................. P. ponuiensis Augener, 1924

— AVII-VIII with more than 36-50 paragnaths, arranged in 4-5 transversal rows; AVI with 8-10 paragnaths; AIII with 11-19 paragnaths; AV with 2-4 paragnaths ..................... P. nuntia (Savigny in Lamarck, 1818)

17(14). AVI with very uneven-length bars (outermost much longer) .......... P. mictodonta ( von Marenzeller, 1879)

— AVI with short even-length bars (some only slightly longer if at all) ..................................................... 18

18(17). Dorsal ligule of even size along body, not projecting beyond end of median ligule in posterior parapodia; AV with paragnaths (when present) placed posteriorly to those of AVI .............. P. gualpensis Jeldes, 1963

— Dorsal ligule barely uneven in posterior parapodia, projecting beyond end of median ligule in posterior parapodia; AV with paragnaths (when present) nearly in conjunction to those of AVI .............................. ................................................................................ P. vallata (Grube & Kröyer in Grube, 1858) , partim.

19(10). AVII-VIII with more than 50 paragnaths in 4-5 transverse rows ..................... P. brevicirris ( Grube, 1866)

— AVII-VIII with up to 35 paragnaths in 2-3 transverse rows .................................................................. 20

20(19). Blades of homogomph spinigers with proximal teeth slender, evenly spaced; heterogomph spinigers absent in anterior chaetigers; gap between AVI and VIII-VIII, broad (as wide as palpophore); AVI with arc of paragnaths sited somewhat oblique .................................................................... P. heterodonta Gravier, 1899

— Blades of homogomph spinigers with proximal teeth notoriously thickened, separated; heterogomph spinigers present throughout body; gap between areas VI and VIII-VIII, narrow (as wide as palpostyle); AVI with arc of paragnaths sited entirely transverse .......................................... P. latipalpa (Schmarda, 1861) n. comb.

Figures

FIG. 1. — Areas VI-V-VI patterns of the pharynx shaped by the ridges and furrows: A-C, Perinereis latipalpa (Schmarda, 1861) n. comb. with a λ-shaped pattern; D-F, Perinereis nuntia (Savigny in Lamarck, 1818) with a χ-shaped pattern; G-I, Perinereis larentukana (Grube in Peters, 1881) n. comb. with a υ-shaped pattern; J-L, Perinereis shikueii Glasby & Hsieh, 2006 with a ɔc-shaped pattern; A, D, G, J, dorsal portion of oral ring; B, E, H, K, same with a slightly irregular line drawings on the shape formed by AVI-V-VI pattern; C, F, I, L, symmetrical line drawings of the AVI-V-VI patterns. Scale bars: 1 mm. J, K, after Glasby & Hsieh (2006).