Aricidea (Acmira) Hartley, 1981

Subgenus Aricidea (Acmira) Hartley, 1981 View in CoL

Type species. Aricidea catherinae Laubier, 1967

Diagnosis: Prostomium subtriangular, pear-shaped to oval, with rounded anterior margin; antenna simple, usually unbranched and unarticulated. Posterior lip of mouth extending through ventral surface of first two chaetigers. Chaetae of three types: limbate in the anterior part, thin capillaries in the post-branchial region, and modified neurochaetae which are heavy, curved spines with or without hood, with or without accessory filaments, teeth or bristles, always thicker than notochaetae and accompanying capillary neurochaetae ( Blake, 2019).

Key to species of Aricidea (Acmira) View in CoL of the world. In square brackets is the region where the type locality is contained.

1 Modified neurochaetae with arista....................................................................... 2

- Modified neurochaetae without arista.................................................................... 23

2(1) Modified neurochaetae with hood........................................................................ 3

- Modified neurochaetae without hood.................................................................... 11

3(2) Modified neurochaetae generally with distal pubescence...................................................... 4

- Modified neurochaetae without pubescence................................................................ 8

4(3) Pubescence in most of the modified neurochaetae, distal arista inserted subdistally; median antenna with thin base and inflated, rounded tip, not extending beyond posterior margin of prostomium............................................................................... A. (A.) filamentosa Barroso, Paiva & Ranauro, 2020 [Espírito Santo Basin, Brazil].

- All neurochaetae modified with pubescence; antenna extending beyond posterior margin of prostomium................ 5

5(4) Antenna inserted anteriorly, reaching middle of chaetiger 1, digitiform, with two sub-distal constrictions and rounded distally; last pair of branchiae narrow and long; modified neurochaetae bearing a tuft of distal pubescence and sometimes a short distal arista................................ A. (A.) bbkingi Barroso, Paiva & Ranauro, 2020 [Espírito Santo Basin, Brazil]

- Antennae smooth, without constrictions, inserted medially; modified neurochaetae with distal or subdistal arista on convex side of shaft............................................................................................. 6

6(5) Antenna extend back to mid part of first chaetiger, digitiform; notopodial postchaetal lobe short and conical in first two chaetigers; modified neurochaetae with distal arista only seen by SEM........................................................................................... A. (A.) blakei sp. nov. [Bahía de los Angeles, Gulf of California]

- Antenna extend back to chaetiger 2 or beyond; notopodial lobe short and cirriform in first two chaetigers............... 7

7(6) Antenna extending to chaetiger 2; digitiform with more or less swollen region above mid-region; notopodial postchaetal lobe in postbranchial segments long, stout, finger-like; with 10–21 pairs of branchiae; modified neurochaetae with distal arista................................................. A. (A.) katzmanni Erdoğan-Dereli & Çinar, 2020 View in CoL [Sea of Marmara]

- Antenna extending to chaetigers 3–6, slightly thicker initially, then tapering, sometimes weakly telescoping then tapering to pointed tip; notopodial lobe in postbranchial segments filiform; with up to 50 pairs of branchiae; modified neurochaeta with subdistal arista on convex side of shaft....... A. (A.) lopezi Berkeley & Berkeley, 1956 View in CoL [ Eastern Pacific , British Columbia]

8(3) Antenna thick, not reaching posterior margin of prostomium; with 28–30 pairs of branchiae, last pair somewhat longer, narrower; modified neurochaetae curved, acicular, with hooked tip bearing 3–4 spines, with subapical hood on concave side of tip......................................................... A. (A.) rubra Hartman, 1963 [off California, USA]

- Antenna reaching chaetiger 4........................................................................... 9

9(8) Antenna long (extends back to chaetiger 2–4), slender; with 19–20 pairs of branchiae, last four pairs are noticeably longer than the width of segment, with a slender filamentous tip; notopodial papilla absent; notopodial lobe in first two prebranchial chaetigers short and cirriform............................................ A. (A.) elongata Imajima, 1973 View in CoL [ Japan] 1

- Antenna short (not exceeding chaetiger 2), broad near base or medially; with up to 16 pairs of branchiae; notopodial papilla present............................................................................................ 10

10(9) Antenna with thin base, central part swollen, then thin and cylindrical in its distal part; notopodial postchaetal lobe thick, short, digitiform in first two chaetigers, becoming thicker and longer with weakly asymmetrical basal swelling from chaetiger 3 to branchial region, long and filiform in postbranchial region... A. (A.) catherinae Laubier, 1967 View in CoL [Mediterranean Sea, France]

- Antenna clavate, unequally bifid distally, with small subterminal process; notopodial postchaetal lobe small, spherical in first two chaetigers, more elongate in the third chaetiger, subulated in branchial region, becoming slenderer and cirriform in postbranchial region........................... A. (A.) philbinae Brown, 1976 View in CoL [East and west coasts of Florida, USA]

11(2) Modified neurochaeta with subterminal pubescence........................................................ 12

- Modified neurochaeta without subterminal pubescence...................................................... 21

12(11) Antenna does not extend beyond the posterior margin of first chaetiger......................................... 13

- Antenna extending to chaetiger 2 or beyond............................................................... 14

13(12) Antenna inserted medially, it reaches back to about the midline of the first chaetiger; notopodial papilla present in first 14 chaetigers; modified neurochaetae with arista inserted medially............................................................................................... A. (A.) laubieri Hartley, 1981 View in CoL [Smith Bank, Moray Firth, Scotland]

- Antenna inserted anteriorly, extending to posterior part of prostomium; notopodial papilla absent; modified neurochaetae with arista inserted distally........................ A. (A.) pseudoassimilis Erdoğan-Dereli & Çinar, 2020 View in CoL [Sea of Marmara]

14(12) Modified neurochaetae with arista inserted subdistally on convex side.......................................... 15

- Modified neurochaetae with arista or long fibrils inserted basally on convex side................................. 18

15(14) Antenna inserted medially, extended beyond the second chaetiger; neuropodial postchaetal lobe present................ 16

- Antenna inserted distally, extended back to chaetiger 2, moderately inflated in proximal region; neuropodial postchaetal lobe absent; notopodial postchaetal lobe cirriform in prebranchial and branchial region.......................................................................................... A. (A.) bispinata Cantone, 1994 View in CoL [Ross Sea, Antarctica]

16(15) Notopodial postchaetal lobe with asymmetrical basal enlargement on branchial region. Modified neurochaetae of two types, with or without terminal arista.......................................................................... 17

- Notopodial postchaetal lobes short, thick and cirriform on first two chaetigers; long and thick between chaetiger 3–6; filiform on posterior chaetigers. Modified neurochaetae of three types: type I long, relatively thin, with a strong and thick arista at tip; type II short, thicker than others, with a distal end curving at 90°, fibrils (hirsute) subterminally; type III short, thick, with a curved distal end and a strong arista at tip, hirsute subterminally...... A. (A.) annae Laubier, 1967 [ Western Mediterranean ]

17(16) Antenna extends back to chaetiger 3–4; with 20–28 pairs of branchiae; modified neurochaetae from chaetiger 20–22; with notopodial papilla.................................................. A. (A.) finitima Strelzov, 1973 View in CoL [Scotia Sea] 2

- Antenna extends back to chaetiger 6; with 12 pairs of branchiae; modified neurochaetae from chaetiger 28–30; notopodial papilla absent...................................................... A. (A.) mirifica Strelzov, 1973 View in CoL [ Antarctica]

18(14) Neuropodial postchaetal lobe present.................................................................... 19

- Neuropodial postchaetal lobe absent..................................................................... 20

19(18) Antenna extending to posterior margin of chaetiger 1, inserted centrally; neuropodial postchaetal lobe from chaetiger 1–19, short, digitiform anteriorly; short, cirriform posteriorly, does not exceed half the size of the neurochaetae............................................................ A. (A.) meridionalis Laubier & Ramos 1974 [Western Mediterranean]

- Antenna extends back to chaetiger 5, inserted distally; neuropodial postchaetal lobe from chaetiger 1–37, slender digitate, as long as the size of the neurochaetae..................................... (A.) (A.) horikoshii Imajima, 1973 [ Japan]

20(18) Antenna clubbed, thin in the proximal part, thickening towards the distal part; notopodial postchaetal lobe short, cylindrical in first two chaetigers, long and subulated on chaetiger 3 and branchial chaetigers.................................................................................................... A. (A.) taylori Pettibone, 1915 View in CoL [Florida, USA]

- Antenna long, thin, extends back to chaetiger 3–10; notopodial postchaetal lobe short and cirriform in first two chaetigers, long and thin on chaetiger 3 and branchial chaetigers, with strongly developed asymmetrical basal enlargement.......................................................................... A. (A.) assimilis Tebble, 1959 [Mediterranean Sea]

21(11) Antenna extends back to chaetiger 2, cirriform; notopodial postchaetal lobe in first two prebranchial chaetigers short and cylindrical; with 10–13 pairs of branchiae.............................................................................................. A. (A.) strelzovi Hartmann-Schröder & Rosenfeldt, 1990 View in CoL [Off Elephant Island, Antarctica]

- Antenna does not reach posterior margin of prostomium; notopodial postchaetal lobe in first two prebranchial chaetigers conical or cirriform........................................................................................ 22

22(21) Antenna oval; notopodial prechaetal lobe in first two prebranchial chaetigers conical; modified neurochaetae from chaetiger 13, with small arista; interramal lobe absent......................... A. (A.) brevicornis ( Hartmann-Schröder, 1962) [ Peru]

- Antenna club-shaped; notopodial prechaetal lobe in first two prebranchial chaetigers cirriform, from chaetiger 3 to 5 with a weak asymmetrical basal enlargement; modified neurochaetae from chaetigers 24–25, with long distal arista; interramal lobe present on branchial segments................................... A. (A.) punctata ( Hartmann-Schröder, 1962) [ Peru]

23(1) Modified neurochaetae with hood....................................................................... 24

- Modified neurochaetae without hood.................................................................... 29

24(23) Modified neurochaetae with distal pubescence; antenna does not reach posterior margin of prostomium............... 25

- Modified neurochaetae without pubescence; antenna extending beyond posterior margin of prostomium............... 26

25(24) Claviform antenna, reaches posterior margin of prostomium; last pair of branchiae shorter than anterior ones; prebranchial notopodial postchaetal lobes short and conical in first two chaetigers, the third three times longer than anterior ones; lobes of branchial chaetigers cirriform, 1/3 the length of branchiae.................... A. (A.) pigmentata Carrasco, 1976 View in CoL [ Chile]

- Antenna swollen basally, extends back to anterior part of third chaetiger; last two pairs of branchiae extremely elongate, with filamentous distal part, two times as long as former; notopodial postchaetal lobe in first two chaetigers extremely small; those of branchial region slender, digitate, 2/3 as long as accompanying branchiae........ A. (A.) eximia Imajima, 1973 View in CoL [ Japan] 3

26(24) Neuropodial postchaetal lobe present; branchiae from chaetiger 3; with 48–68 pairs of branchiae, last one shorter than anterior ones; notopodial postchaetal lobe from first chaetiger long, digitiform, that of the second chaetiger slightly longer; postchaetal lobe cirriform in branchial and postbranchial region.................................................................................. A. (A.) anusakdii Plathong, Hernández-Alcántara, Harris & Plathong, 2020 [Gulf of Thailand] 4

- Neuropodial postchaetal lobe absent..................................................................... 27

27(26) Interramal lobe present as rudimentary ridges in branchial region; antenna thick, finger like, with dense ciliation, inserted in mid prostomium, not reaching chaetiger 1; notopodial postchaetal lobe short and cirriform in first two chaetigers, longer, thick, finger like from chaetigers 3 to 20; thin, long and filiform in postbranchial chaetigers..................................................................................... A. (A.) cerruti Laubier, 1966 View in CoL [Western Mediterranean Sea]

- Interramal lobe absent................................................................................ 28

28(27) Antenna inserted in mid prostomium; notopodial postchaetal lobe tuberculate in chaetigers 1–5, cirriform from chaetiger 6 to the end of branchial region, long and filiform with spherical tip in postbranchial region............................................................................... A. (A.) pearti Barroso, Paiva & Ranauro, 2020 View in CoL [Eastern Brazil]

- Antenna inserted in mid anterior prostomium; notopodial postchaetal lobe bulbous in first two chaetigers, digitiform from third chaetiger and branchiate region, becoming filiform posteriorly............. A. (A.) cerruti View in CoL pacifica Imajima, 1973 [ Japan]

29(23) Modified neurochaetae with distal pubescence............................................................. 30

- Modified neurochaetae without pubescence............................................................... 31

30(29) Antenna proximally inflated, tapering to short blunt end, does not reach posterior margin of prostomium; last four pairs of branchiae smaller than others; modified neurochaetae from chaetiger 18 with blunt shaft surrounded by pubescence in median and distal end of chaetae, some with one or two distal filaments clearly long; neuropodial postchaetal lobe absent........................ A. (A.) hirsuta Arriaga-Hernández, Hernández-Alcántara & Solís-Weiss, 2013 View in CoL [ Southern Gulf of Mexico]

- Antenna slender, extending back to anterior part of chaetiger 3; posterior branchiae longer than anterior ones; modified neurochaetae from chaetiger 31, with hirsute tip, anterior filaments noticeably long; neuropodial postchaetal lobe present as inconspicuous low tubercles.................................... A. (A.) flava Zhou & Reuscher, 2013 [Chinese Sea]

31(29) With up to eight pairs of branchiae...................................................................... 32

- With more than 14 pairs of branchiae.................................................................... 33

32(31) With four pairs of branchiae increasing slightly in size posteriorly; neuropodial modified neurochaetae present from chaetiger 40, curved, falcate; notopodial postchaetal lobe in first chaetiger inconspicuous, digitiform in second and third; cirriform in branchial chaetigers........................ A. (A.) tetrabranchia Hartman & Fauchald, 1971 [Western North Atlantic]

- With four to eight pairs of branchiae (very fragile, have fallen off on all specimens of the type description, only distinguished by the branchial bases); modified neurochaetae from chaetiger 20–22, with three types: slightly curved and strongly pointed hooks, thick, but with elongated tip, and with strongly curved tip; notopodial postchaetal lobe in first two chaetigers minute, semispherical, those of third chaetiger digitiform; in branchial region cirriform, increasing in size to posterior chaetigers..................................... A. (A.) jeaneteae Langeneck, Busoni, Aliani & Castelli, 2017 [ Western Ionian Sea ]

33(31) Modified neurochaetae thick, curved distally at an angle of 90°............................................... 34

- Modified neurochaetae thin, slightly curved............................................................... 35

34(33) With 16 to 18 pairs of branchiae; notopodial postchaetal lobe in first chaetiger conical; in second and third chaetigers and branchial region digitate, but in branchial region shorter than in chaetigers 2 and 3; in postbranchial region thin, filiform.............................................................. A. (A.) neosuecica nipponica Imajima, 1973 View in CoL [ Japan]

- With 30 pairs of branchiae; notopodial postchaetal lobe in first two chaetigers cirriform, in third chaetiger longer than previous chaetigers; in branchial region cirriform, 2/3 the branchial size; in postbranchial region similar, slightly shorter than those of branchial region..................................... A. (A.) simplex Day, 1963 View in CoL [West of Cape Town, South Africa]

35(33) Antenna does not reach the posterior margin of prostomium.................................................. 36

- Antenna slender, inserted medially, reaching chaetiger 2; prostomium distally trilobate; modified neurochaetae of two kinds: with mucronate tips, and thin, slightly recurved; notopodial postchaetal lobe in first two chaetigers extremely small, inconspicuous.................................................................... A. (A.) trilobata Imajima, 1973 [ Japan]

36(35) Prostomium subtriangular, with frontal eversible palpode; antenna papilliform, inserted medially; branchiae from chaetiger 3, with 18–30 pairs of branchiae, last two pairs smaller than previous ones; notopodial postchaetal lobe in first two chaetigers cirriform........................................ A. (A.) simonae Laubier & Ramos, 1974 View in CoL [Mediterranean, France] 6

- Prostomium trilobate, wider than long; antenna short, slender, inserted posteriorly; with 13–14 pairs of branchiae, last five pairs decrease evenly in size, slender tips become less distinct than in anterior branchial segments; notopodial postchaetal lobe in first two chaetigers short and digitate............... A. (A.) crassicapitis Fauchald, 1972 [ Cedros Island , Off Western Mexico]