Diplocirrus Haase, 1915

Salazar-Vallejo, Sergio I., 2020, Four new deep-water flabelligerid species from Pacific Costa Rica (Annelida Sedentaria, Flabelligeridae), Zootaxa 4885 (4), pp. 560-578 : 565-566

Key to species of Diplocirrus Haase, 1915 , restricted

(modified from Jimi et al. 2017)

1 Body papillae abundant, short, giving a velvety appearance.................................................... 2

- Body papillae scarce, long, tunic looks bare............................................ Diplocirrus sp. Sri Lanka

2(1) Body without sand particles............................................................................. 3

- Body with sand particles.............................................................................. 11

3(2) Ventrolateral gonopores present in some anterior chaetigers .................................................... 4

- Ventrolateral gonopores absent ........................................................................... 9

4(3) First chaetiger with long chaetae, about half as long as body width; caruncle posteriorly expanded...................................................................................... .... D. erythroporus Gallardo, 1968 Vietnam

- Anterior end with short chaetae, 1/3–1/5 as long as body width; caruncle posteriorly tapered......................... 5

5(4) Branchiae with lamellae............................................................................... 6

- Branchia without lamellae.............................................................................. 7

6(5) Median chaetigers with neurochaetae tapered, 22–25 articles, and tip delicately falcate; cirriform branchiae with lamellae along basal 1/4–1/5 of each filament............................................ D. branchiatus ( Rullier, 1965) Australia

- Median chaetigers with neurochaetae barely tapered, 8–11 articles, and tip markedly falcate; cirriform branchiae with lamellae along basal 1/3–1/2 of each filament.................................. D. nicolaji ( Buzhinskaja, 1994) Russia, Japan

7(5) Dorsal branchiae as long as ventral ones; caruncle shorter than palp scar... D. mamoi Jimi, Fujiwara & Kajihara, 2017 Japan

- Dorsal branchiae shorter than ventral ones; caruncle longer than palp scar............................................................................................... D. asamushiensis Jimi, Fujiwara & Kajihara, 2017 Japan

8(3) Papillae digitate, longer than wide; chaetiger 1 with notochaetae fragile, if complete, as long as body width.. ............ 9

- Papillae hemispherical, about as long as wide; cephalic cage chaetae shorter than body width....................... 10

9(8) Median chaetigers with neurochaetae with articles slightly longer than wide; body brownish................................................................................................. D. capensis Day, 1961 South Africa

– Median chaetigers with neurochaetae with articles 4–6 times longer than wide; body yellowish................................................................................... D. imajimai Jimi, Fujiwara & Kajihara, 2017 Japan

10(8) Median chaetigers with 5–6 neurochaetae, shorter than notochaetae, with articles 2.0–2.5 times longer than wide.................................................... D. kudenovi Salazar-Vallejo & Buzhinskaja, 2011 Eastern Pacific Ocean

- Median chaetigers with 2–3 neurochaetae, about as long as notochaetae, with articles 7–8 times longer than wide........................................................... D. stopbowitzi Darbyshire & Mackie, 2009 Southern Irish Sea

11(2) Anterior chaetigers barely wider than following ones........................................................ 12

- Anterior chaetigers swollen, much wider than following ones................................................. 13

12(11) Some lateral papillae twice as long as in chaetal lobes................. D. rugosus Teixeira, Rizzo & Santos, 2015 Brazil

- Lateral papillae shorter.. ............................................................ Diplocirrus sp. Morocco

13(11) Lateral papillae 1/25–1/5 as long as longest notochaetae..................................................... 14

- Lateral papillae 1/3–5/6 as long as longest notochaetae...................................................... 18

14(13) Ventrolateral gonopores present........................................................................ 15

- Ventrolateral gonopores absent......................................................................... 16

15(14) Cephalic cage well developed (2/3 as long as body width)............. D. ohtsukai Jimi, Fujiwara & Kajihara, 2017 Japan

- Cephalic cage poorly developed (1/4 as long as body width)....... D. salazarvallejoi Teixeira, Rizzo & Santos, 2015 Brazil

16(14) Cephalic cage well developed (as long as body width)....................................................... 17

- Cephalic cage poorly developed (1/3 as long as body width)....... .. D. tohokuensis Jimi, Fujiwara & Kajihara, 2017 Japan

17(16) Neurochaetal rounded projection present in each article............ D. toyoshioae Jimi, Fujiwara & Kajihara, 2017 Japan

- Neurochaetal rounded projection absent..................................... D. glaucus ( Malmgren, 1867) Norway

18(13) Lateral papillae in chaetal lobe short (1/3 as long as notochaeta); anterior part (roughly corresponding to chaetigers 1–3) not pigmented............................................. .. D. incognitus Darbyshire & Mackie, 2009 South Africa

- Lateral papillae in chaetal lobe long (5/6 as long as notochaeta); anterior part (chaetigers 1–3) with rusty pigments.................................................................... D. seisuiae Jimi, Fujiwara & Kajihara, 2017 Japan