Perinereis Kinberg, 1865

Prajapat, Vaishali, Villalobos-Guerrero, Tulio F. & Vachhrajani, Kauresh D., 2024, Two new species of Perinereis Kinberg, 1865 (Annelida: Nereididae) from the rocky shore of Maharashtra, India, including notes and an identification key to Group 1, European Journal of Taxonomy 935, pp. 256-282 : 259-264

Genus Perinereis Kinberg, 1865

Type species

Perinereis novaehollandiae Kinberg, 1865 , by subsequent designation (fide Hartman 1949). It is currently regarded as a junior synonym of P. amblyodonta Schmarda, 1861 ( Ehlers 1904; Hartman 1959).

Key to all species of Perinereis Kinberg, 1865 belonging to Group 1

Perinereis G1 has been pragmatically categorised into two groups depending on the expansion of the dorsal ligule in posterior chaetigers: subgroup 1A (slightly or not expanded) and subgroup 1B (greatly expanded). Considering the division proposal of dorsal ligules into distal and proximal regions (see Villalobos-Guerrero et al. 2021a), species of subgroup 1B show a distinct enlargement towards the posterior end. The distal region may also experience slight modifications, although they are much less marked than the proximal one. Hence, the species of the subgroups A and B of Perinereis are redefined as follows (after Hutchings et al. 1991): (A) the proximal region of dorsal ligule slightly or not expanded in posterior chaetigers; and (B) the proximal region of dorsal ligule greatly expanded in posterior setigers.

The key includes all species now regarded as Perinereis G1 sensu Hutchings et al. (1991). However, P. cavifrons ( Ehlers, 1920) , P. curvata Holly, 1935 , and P. dongalae ( Horst, 1924) are excluded for being known only for their epitokous morphology but without detailed description of the dorsal ligule in posterior parapodia.

Perinereis cavifrons , originally described from Indonesia, resembles P. rullieri Pilato, 1974 (subgroup 1A) by having dorsal cirri not projecting beyond the distal region of the dorsal ligule, area V with three paragnaths, neuropodial superior lobe, and by lacking notopodial prechaetal lobe and postchaetal lobes. Nevertheless, P. cavifrons has a shorter and more robust median ligule (1.3 × as long as neuroacicular ligule) in anterior chaetigers than in P. rullieri (more elongate, 2 × as long as neuroacicular ligule). Also, P. cavifrons has 3–4 teeth on its jaws, in contrast to 6–7 in P. rullieri .

Perinereis curvata described from Hawaii is similar to Perinereis falklandica ( Ramsay, 1914) and P. tobeloana ( Augener, 1933) , both belonging to subgroup 1B, by the long dorsal cirrus and the absence of notopodial prechaetal and neuropodial superior and postchaetal lobes. However, P. curvata (area I: 2–3; area V: 1; areas VII–VIII: 34–36) can be distinguished from P. falklandica (area I: 32–150; areas VII–VIII: 110–300) by having fewer paragnaths on areas I and VII–VIII, and also from P. tobeloana (area V: 3; areas VII–VIII: 8) by the number of paragnaths on areas V and VII–VIII.

Perinereis dongalae from Indonesia was briefly described by Horst (1924) with a single illustration (heterogomph falciger). Several diagnostic characters were not considered, although a few included help distinguish it from all the Perinereis G1 species, except P. obfuscata ( Grube, 1878) (subgroup 1A). Perinereis dongalae was synonymized with P. obfuscata by Hylleberg et al. (1986), although this was rejected by Hutchings et al. (1991) since the former authors did not examine the type material. Based on the literature, it is here found that both species share dorsal cirri barely or not projecting beyond the distal region of the dorsal ligule, area I with 7 or more paragnaths, area V with one paragnath, tentacular cirri extending to chaetiger 5, and black transverse band on each segment. Nevertheless, no remarkable differences were detected between these two species. A redescription of P. dongalae is needed to clarify its valid status.

1. Proximal region of dorsal ligule barely or not enlarged in posterior parapodia (Subgroup 1A) ...... 2

– Proximal region of dorsal ligule markedly enlarged in posterior parapodia (Subgroup 1B) ......... 25

2. Dorsal cirri short, barely or not projecting beyond distal region of dorsal ligule in mid-body parapodia ........................................................................................................................................... 3

– Dorsal cirri long, projecting distinctly beyond distal region of dorsal ligule in mid-body parapodia ......................................................................................................................................... 18

3. Neuropodial postchaetal lobe present throughout ............................................................................ 4

– Neuropodial postchaetal lobe absent throughout .............................................................................. 6

4. Aciculae light yellow; dorsal cirri placed basally on dorsal ligule in posterior parapodia; area V without paragnaths; neurochaetae with homogomph falcigers ... P. tenuisetis ( Fauvel, 1915) ( Italy)

– Aciculae dark brown or black; dorsal cirri placed medially or subdistally on dorsal ligule in posterior parapodia; area V with paragnaths; neurochaetae with heterogomph falcigers ….. 5

5. Areas VII–VIII with anterior band having two rows of paragnaths (one on furrows and one on ridges); area III without laterally isolated paragnaths; area I with more than 10 paragnaths; subacicular neurochaetae with homogomph spinigers ............................ P. arabica Mohammad, 1971 ( Kuwait)

– Areas VII–VIII with anterior band having only furrow row of paragnaths; area III with laterally isolated paragnaths; area I with up to 2 paragnaths; subacicular neurochaetae with heterogomph spinigers ................................................................................ P. taorica Langerhans, 1881 (Madeira)

6. Areas VII–VIII without paragnaths .................................................................................................. 7

– Areas VII–VIII with 10 or more paragnaths ……………………………………………….. 8

7. Dorsal surface of chaetigers 1 and 5–7 with well-defined brown bands; tentacular and anal cirri lacking brown stripe ........................................ P. pictilis Glasby, Nu-Wei & Gibb, 2013 ( Australia)

– Dorsal surface from chaetiger 2 with two transverse brown bands, reducing in intensity posteriorly; tentacular and anal cirri with longitudinal brown stripe ....... P. suluana ( Horst, 1924) ( Philippines) 1

8. Notopodial prechaetal lobe present throughout ................................................................................ 9

– Notopodial prechaetal lobe absent throughout ............................................................................... 14

9. Neuropodial superior lobe absent throughout ................................................................................. 10

– Neuropodial superior lobe present throughout ................................................................................11

10. Distal dorsal ligule bluntly conical in anterior parapodia; dorsal cirri located subdistally on dorsal ligule in posterior parapodia; jaws with 4–5 teeth; area III with up to 5–12 paragnaths, with laterally isolated cones; areas VII–VIII with small and delicate paragnaths .................................................... ....................................................................................................... P. cultrifera ( Grube, 1840) ( Italy)

– Distal dorsal ligule bluntly rounded in anterior parapodia; dorsal cirri located medially on dorsal ligule in posterior parapodia; jaws with up to 3 teeth; area III with up to 5 paragnaths, without laterally isolated cones; areas VII–VIII with coarse paragnaths ........................................................ ......... P. louizomarum Rezzag Mahcene, Villalobos-Guerrero, Kurt, Denis & Daas, 2023 ( Algeria)

11. Area V without paragnaths; area III without laterally isolated paragnaths ........................................ ............................................................ P. calmani ( Monro, 1926) ( Australia and Macclesfeld Bank)

– Area V with paragnaths; area III with laterally isolated paragnaths ............................................... 12

12. Area V with 3 paragnaths (rarely 1) .............................. P. nigropunctata ( Horst, 1889) ( Malaysia) 2

– Area V with 1 paragnath (rarely 2) ................................................................................................. 13

13. Postero-dorsal tentacular cirri reaching chaetiger 8, 2 × as long as palps; most segments dorsally with 3 short brown transverse lines .................................... P. striolata ( Grube, 1878) ( Philippines) 2

– Postero-dorsal tentacular cirri reaching up to chaetiger 5, slightly as long as palps; dorsum of anterior segments with one black transverse line on each side of posterior margin ........................................ ........................................................................................... P. obfuscata ( Grube, 1878) ( Philippines) 1

14. Neuropodial superior lobe absent throughout; postero-dorsal tentacular cirri reaching up to chaetiger 2; area IV with 40 or more paragnaths ............................................................................................... P. iranica Bonyadi-Naeini, Rastegar-Pouyani, Rastegar-Pouyani, Glasby & Rahimian, 2018 ( Iran) 3

– Neuropodial superior lobe present throughout; postero-dorsal tentacular cirri reaching chaetiger 5 or higher; area IV with up to 25 paragnaths ........................................................................................ 15

15. Area V with 3 or more paragnaths (rarely 2) .................................................................................. 16

– Area V with 1 paragnath ................................................................................................................. 17

16. Tentacular belt with eye-glass-shaped pigmentation pattern; area I with 5 paragnaths; area III with 26 paragnaths; area II with 12 paragnaths .................... P. perspicillata ( Grube, 1878) ( Philippines) 2

– Tentacular belt without distinct pigmentation pattern; area I with up to 2 paragnaths; area III with up to 9 paragnaths; area II with 4−10 paragnaths ..................................... P. rullieri Pilato, 1974 ( Italy)

17. Area III without laterally isolated paragnaths; postero-dorsal tentacular cirri reaching chaetiger 5; jaws with up to 4 teeth ..................................... P. atlantica ( McIntosh, 1885) ( Cape Verde Islands) 4

– Area III with laterally isolated paragnaths; postero-dorsal tentacular cirri reaching chaetiger 7−8; jaws with 7−8 teeth …………………….….. P. floridana ( Ehlers, 1868) (Atlantic USA)

18. Neuropodial postchaetal lobe present throughout; area V without paragnaths .................................. ......................................................................................... P. capensis ( Kinberg, 1865) ( South Africa)

– Neuropodial postchaetal lobe absent throughout; area V with paragnaths ………………. 19

19. Areas VII–VIII with anterior band having two rows of paragnaths (one on furrows and one on ridges); area III without laterally isolated paragnaths …………………………… 20

– Areas VII–VIII with anterior band having only furrow row of paragnaths; area III with laterally isolated paragnaths .......................................................................................................................... 23

21. Notopodial prechaetal lobe present throughout; area IV with smooth bars in addition to cones; area III with up to 8 paragnaths ..................................................... P. barbara ( Monro, 1926) ( Australia) 6

– Notopodial prechaetal lobe absent throughout; area IV with cones only; area III with 17 or more paragnaths ....................................................................................................................................... 22

22. Distal region of dorsal ligule bluntly conical (as long as wide) throughout; heterogomph falcigers with serrations present in about half of total blade length; area II with up to 7 paragnaths .................................................................. P. falsovariegata Monro, 1933 ( South Africa)

– Distal region of dorsal ligule bluntly triangular (as long as wide) throughout; heterogomph falcigers with serrations present in about one-sixth of total blade length; area II with 12 or more paragnaths ..................................................................... P. villalobosi Rioja, 1947 (Mexican Pacific)

23. Notopodial prechaetal lobe present throughout; neuropodial superior lobe absent throughout ......... ................................................................................................. P. helleri ( Grube, 1878) ( Philippines)

– Notopodial prechaetal lobe absent throughout; neuropodial superior lobe present throughout ..... 24

24. Ridges of area VI distally separated from each other (areas VI–V–VI ridge pattern π-shaped); area V with three paragnaths (seldom 4); area IV with smooth bars in addition to cones ......................... ........................................................................................................ P. misrai sp. nov. (Western India)

– Ridges of area VI distally and sub-medially coalesced (areas VI–V–VI ridge pattern λ-shaped); area V with one paragnath; area IV with cones only ............... P. websteri Conde-Vela, 2022 ( Bermuda) 6

25. Dorsal cirri short, barely or not projecting beyond distal region of dorsal ligule in mid-body parapodia ......................................................................................................................................... 26

– Dorsal cirri long, projecting distinctly beyond distal region of dorsal ligule in mid-body parapodia ......................................................................................................................................................... 36

26. Neuropodial superior lobe absent throughout ................................................................................. 27

– Neuropodial superior lobe present throughout ............................................................................... 28

27. Area V with 3 paragnaths; area III with up to 17 paragnaths; area IV with up to 22 paragnaths ....... ................................................................................................ P. malayana ( Horst, 1889) ( Malaysia)

– Area V with 1 paragnath; area III with 24 or more paragnaths; area IV with 28 or more paragnaths ................................................................................................... P. oliveirae ( Horst, 1889) ( Portugal)

28. Ridges of area VI distally separated from each other (areas VI–V–VI ridge pattern π-shaped) .... 29

– Ridges of area VI distally and sub-medially coalesced (areas VI–V–VI ridge pattern λ-shaped). 31

29. Area V with many paragnaths; areas VII–VIII with more than 70 paragnaths, minute; area I with 2 paragnaths; area III with 30 or more paragnaths, with laterally isolated cones; area IV with smooth bars in addition to conical paragnaths ................................................................................................ ................................................... P. marionii (Audouin & Milne-Edwards, 1833) (English Channel)

– Area V with 1 paragnath; areas VII–VIII with up to 40 paragnaths, medium or large; area I with 7 or more paragnaths; area III with up to 18 paragnaths, without laterally isolated cones; area IV with conical paragnaths only .................................................................................................................. 30

30. Area III with 16 or more paragnaths; dorsal ligules 2.3 × as long as median ligules in posterior chaetigers; ventral ligules shorter than neuroacicular ligules in posterior chaetigers ........................ ....................................................................................................... P. ponteni Kinberg, 1865 ( Brazil)

– Area III with up to 6 paragnaths; dorsal ligules 3.3 × as long as median ligules in posterior chaetigers; ventral ligules as long as neuroacicular ligules in posterior chaetigers .............................................. ................................................................................................ P. bairdii ( Webster, 1884) ( Bermuda) 5

31. Areas VII–VIII with anterior band having two rows of paragnaths (one on furrows and one on ridges); areas VII–VIII with up to 7 paragnaths; subacicular neurochaetae with homogomph spinigers ....... ................................. P. bajacalifornica de León-González & Solís-Weiss, 1998 (Mexican Pacific) 7

– Areas VII–VIII with anterior band having only furrow row of paragnaths; areas VII–VIII with 18 or more paragnaths; subacicular neurochaetae with heterogomph spinigers ...................................... 32

32. Area V without paragnaths; areas VII–VIII with up to 24 paragnaths; area IV with up to 11 paragnaths; area II with up to 6 paragnaths .......................... P. pseudocavifrons Fauvel, 1930 ( New Caledonia)

– Area V with 1−3 paragnaths; areas VII–VIII with 32 or more paragnaths; area IV with 14 or more paragnaths; area II with 8 or more paragnaths ................................................................................ 33

33. Notopodial prechaetal lobe present throughout .............................................................................. 34

– Notopodial prechaetal lobe absent throughout ................................................................................. 5

34. Area VI with shield-shaped bars; area III without laterally isolated cones; dorsal ligules thrice as long as median ligules in posterior chaetigers; dorsal cirri extending to half of distal region of dorsal ligule in mid-body parapodia ......................................... P. euiini Park & Kim, 2017 ( South Korea) 8

– Area VI with crescent-shaped bars; area III with laterally isolated cones; dorsal ligules 2 × as long as median ligules in posterior chaetigers; dorsal cirri extending to three-quarters of distal region of dorsal ligule in mid-body parapodia .................................. P. malabarensis sp. nov. (Western India)

35. Area VI with bar-shaped paragnaths only; area III without laterally isolated cones; area I with 15 or more paragnaths; area IV with up to 20 paragnaths ........................................................................... .................................................................................... P. elenacosoae Rioja, 1947 (Mexican Pacific)

– Area VI with bar-shaped and conical paragnaths; area III with laterally isolated cones; area I with up to 4 paragnaths; area IV with 40 or more paragnaths ......................................................................... ............................................................................ P. longidonta Rozbaczylo & Castilla, 1973 ( Chile)

36. Areas VII–VIII with up to 8 paragnaths ......................... P. tobeloana ( Augener, 1933) ( Moluccas) 9

– Areas VII–VIII with 30 or more paragnaths ................................................................................... 37

37. Neuropodial superior lobe absent throughout; area I with 30 or more paragnaths; areas VII–VIII with 110−300 paragnaths ..................................... P. falklandica ( Ramsay, 1914) ( Falkland Islands)

– Neuropodial superior lobe present throughout; area I with up to 7 paragnaths; areas VII–VIII with up to 70 paragnaths ......................................................................................................................... 38

38. Notopodial prechaetal lobe present throughout; area V with 1 paragnath; area II with 6 paragnaths ..................................................................................... P. monterea ( Chamberlin, 1918) (California)

– Notopodial prechaetal lobe absent throughout; area V with 3 or more paragnaths; area II with 8−28 paragnaths ....................................................................................................................................... 39

39. Area III with laterally isolated cones .............................................................................................. 40

– Area III without laterally isolated cones ......................................................................................... 41

40. Dorsal ligule 3 × as long as median ligules in posterior chaetigers; areas VII–VIII with up to 50 paragnaths, in two well-defined bands; areas VII–VIII with distal row of paragnaths on furrows and ridges .......................................................................... P. amblyodonta ( Schmarda, 1861) ( Australia)

– Dorsal ligule 5 × as long as median ligules in posterior chaetigers; areas VII–VIII with 55 or more paragnaths, in one irregular band; areas VII–VIII with distal row of paragnaths on furrows only .... ................................................................................................ P. macropus ( Claparède, 1870) ( Italy)

41. Dorsal ligule sub-rectangular, 2.5−3 × as long as median ligules in posterior chaetigers; postero-dorsal tentacular cirri extending to chaetigers 2−3; area III with up to 13 paragnaths; area I with up to 2 paragnaths; area IV with smooth bars in addition to cones ......................................................... ....................................................................................... P. pseudocamiguina Augener, 1922 ( Chile)

– Dorsal ligule ovoid, 2 × as long as median ligules in posterior chaetigers; postero-dorsal tentacular cirri extending to chaetiger 1; area III with 19 paragnaths; area I with 5 paragnaths; area IV with cones only ................................................................................ P. anderssoni Kinberg, 1866 ( Brazil)

Remarks

1 This species is here regarded as a subgroup 1A member based on the original description, contrary to Hutchings et al. (1991), who treated it as in the subgroup 1B.

2 This species is here regarded as a subgroup 1A member based on the original description, contrary to Hutchings et al. (1991) which treated the condition of the dorsal notopodial lobe as unknown.

3 Newly incorporated into subgroup 1B after Bonyadi-Naeini et al. (2018).

4 Newly incorporated into subgroup 1B after Darbyshire (2014).

5 This species is here regarded as a subgroup 1A member based on the original description and the redescription by Hutchings et al. (1991), who treated it in the subgroup 1B.

6 Newly incorporated into subgroup 1B after Conde-Vela (2022).

7 de León-González & Solís-Weiss (1998) originally included the species in subgroup 1B.

8 Newly incorporated into subgroup 1B after Park & Kim (2017).

9 This species is morphologically similar to Pseudonereis Kinberg, 1865 , and should probably be transferred after reviewing the type material. Areas II, III and IV are of the Pseudonereis type ( Augener 1933: 118), which may suggest the presence of both P-bars and comb-like rows of paragnaths, and the elongated proximal region of dorsal ligule with terminal dorsal cirri ( Augener 1933: fig. 10b) suits well with those recently redescribed in P. mancorae ( Berkeley & Berkeley, 1961) and P. pseudonoodti ( Fauchald, 1977) (see Villalobos-Guerrero & Idris 2020).