Aricidea ( Acmira ) Hartley, 1981

León-González, Jesús Angel De, Díaz-Castañeda, Victoria & Hernández, María Ana Tovar-, 2025, On two new paraonids (Annelida, Paraonidae) from Bahía de los Angeles, Gulf of California, Mexico, Zootaxa 5601 (1), pp. 63-85 : 65-74

Subgenus Aricidea ( Acmira) Hartley, 1981

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) 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 [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 [ 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 [ 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 [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 [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 [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 [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 [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 [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 [ 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 [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 [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 [ 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 [ 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 [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 [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 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 [ 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 [ 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 [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 [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]