An Acad Bras Cienc (2022) 94(Suppl. 4): e20210283 DOI 10.1590/0001-3765202220210283
Anais da Academia Brasileira de Ciências | Annals of the Brazilian Academy of Sciences
Printed ISSN 0001-3765 I Online ISSN 1678-2690
www.scielo.br/aabc | www.fb.com/aabcjournal
ANIMAL SCIENCE
A new species of Euclymene (Maldanidae,
Annelida) from Brazil, with new combinations,
and phylogenetic implications for Euclymeninae
JOSÉ ERIBERTO DE ASSIS, JOSÉ ROBERTO BOTELHO DE SOUZA, KIRK FITZHUGH
& MARTIN LINDSEY CHRISTOFFERSEN
Abstract: Maldanids are tube-building polychaetes, known as bamboo-worms; inhabit
diverse marine regions throughout the world. The subfamily Euclymeninae was proposed
to include forms with anal and cephalic plates, a funnel-shaped pygidium, and a terminal
anus. Euclymene, the type genus of Euclymeninae, has about 18 valid species. Euclymene
vidali sp. nov. is defined and members of the species described from Northeastern
Brazil. Members of this species have 23 chaetigers, and one pre-pygidial achaetous
segment; nuchal grooves extend through three quarters of the cephalic plate, and there
is one acicular spine with a denticulate tip. Euclymene africana, and E. watsoni, are here
recognized, respectively, as Isocirrus africana comb. nov., and I. watsoni comb. nov. Three
monotypic genera are invalid: Macroclymenella, Eupraxillella, and Pseudoclyemene; their
species should be recognized as Clymenella stewartensis com. nov., Praxillella antarctica
com. nov., and Praxillela quadrilobata com. nov., respectively. An identification key and
a comparative table for all species of Euclymene are provided. A comparative table for
all genera of Euclymeninae is also furnished. The paraphyletic status of Euclymene and
Euclymeninae is discussed. The taxon Maldanoplaca is not code compliant and should
only be regarded as an informal name.
Key words: Euclymeninae, Maldanidae, new species, polychaeta, systematics.
INTRODUCTION
Maldanids are sedentary, tube-building
polychaetes, commonly known as bamboo
worms (Fauchald 1977, Imajima & Shiraki 1982,
Lee & Paik 1986, Fauchald & Rouse 1997, Rouse
2001, De Assis & Christoffersen 2011). Their tubes
are constructed either horizontally, with sand
and shell fragments under rocks, or vertically in
sandy bottoms with fine sand in marine regions,
or with mud in estuaries (Day 1967, JiménezCueto & Salazar-Vallejo 1997, De Assis et al. 2007).
Tubes are mucus-lined or have an inner organic
sheath secreted by the worm. The internal fibers
of this sheath may become hardened by the
incorporation of fine sediment (e.g., mud), and
these may become agglutinated into several
layers (Pilgrim 1977, Shcherbakova et al. 2017).
Individual species are found in estuaries, or
from other intertidal habitats to the deep sea
(Arwidsson 1906, Chamberlin 1919, De Assis et
al. 2007).
Arwidsson (1906) presented a revision
of maldanids based on the Scandinavian
and Arctic fauna. He proposed the subfamily
Euclymeninae to include forms with cephalic
and anal plates, and a funnel-shaped pygidium
bordered by cirri or crenulated. All euclymenins
present a terminal anus, and members of some
species have a ventral valve. In this revision,
Arwidsson proposed Isocirrus to include species
An Acad Bras Cienc (2022) 94(Suppl. 4)
JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
with members that have anal cirri of the same
length. On the other hand, comparisons among
members of species have shown that members
of Euclymene have at least one midventral cirrus
longer than remaining cirri (Salazar-Vallejo 1991).
Members of Euclymene present the
following features: 18‒24 chaetigers, and one or
more achaetous preanal segments; longitudinal
glandular stripes can be present among members
of some species. The presence of a midventral
cirrus that is longer than remining cirri has been
the main feature used to distinguish this genus
(Quatrefages 1865, 1866, Arwidsson 1906, Day
1955, 1967, De Assis & Christoffersen 2011, De Assis
et al. 2012). However, Euclymene is paraphyletic
(De Assis, pers. obs.) and this character is not
unique to members of the genus (see below).
Members of Euclymene occur from estuarine
and intertidal regions to the deep sea, in sandy
bottoms or on coral reefs (Jiménez-Cueto &
Salazar-Vallejo 1997). They have been reported
from all oceans, especially in shallow coastal
regions. However, most reports are from European
waters, the North Atlantic and Mediterranean
(Fauvel 1927, Read & Fauchald 2020). Members
of the following species have been recorded
from Brazil: E. droebachiensis (M. Sars, 1872),
described originally from Faroe Island, North
Atlantic, and E. coronata Verrill, 1900, described
originally from Castle Island, Boston, USA, were
subsequently reported from the north coast of
the State of São Paulo; E. oerstedii (Claparède,
1863), described originally from Normandy,
Atlantic Ocean, and reported from the northern
coast of São Paulo and Guanabara Bay, State
of Rio de Janeiro; E. lombricoides (Quatrefages,
1865), described originally from BoulogneSur-Mer and Calais Beach, France, have been
collected in Bacia de Campos, Rio de Janeiro
(Amaral et al. 2013), and E. coronata are reported
from northeastern Brazil (De Assis et al. 2012).
The aim of this study is to present a
new Euclymene species, with members from
northeastern Brazil, and to transfer E. africana
(Gravier, 1905) and E. watsoni (Gravier, 1905) to
Isocirrus Arwidsson, 1906. In addition, we discuss
the status of Euclymeninae as a phylogenetic
hypothesis.
The ZooBank Life Science Identifier
(LSID) of this publication is: urn:lsid:zoobank.
org:pub:37A4F888-E91C-4017-9F3A-906CDE8F186C.
MATERIALS AND METHODS
Specimens of the new species were collected
in the estuary of Diogo Lopes Macau, Rio
Grande do Norte, and the estuary from Barra
de Mamanguape River, Rio Tinto, Paraíba, both
in northeastern Brazil (Fig. 1). Specimens were
fixed in 10% seawater-formalin, and later rinsed
with fresh water, then preserved in 70% ethanol.
Specimens were observed with a Zeiss stereo
microscope. Rostrate and acicular hooks were
observed with an Olympus BX41 compound
microscope. For scanning electron microscopy,
worms were washed twice in a 0.1 M phosphate
buffer (pH 7.2) for 2 h at room temperature. They
were then fixed again in 1% osmium tetroxide with
a phosphate buffer for 1 h at room temperature.
All worms were dehydrated into 100% ethanol,
critical-point-dried in CO2, mounted on stubs,
coated with gold, and examined using a JEOL
25SII scanning electron microscope. The type
material is deposited in Universidade Federal
da Paraíba, CIPY-POLY-UFPB. All line drawings
were made using a camera lucida. Illustrations
were prepared using CorelDraw. Measurements
are in millimeters and microns.
The treatment of taxa in this paper follows
from the view that they are explanatory
hypotheses, as opposed to being ontological
entities, individuals, things, or just groupings
of individuals (Fitzhugh 2005, 2008, 2009,
An Acad Bras Cienc (2022) 94(Suppl. 4) e20210283
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 1. Map of distribution of Euclymene species, including the new species described in this paper. (1) E. vidali
sp. nov., (2) E. coronata, (3) E. dispar, (4) E. luderitziana, (5) E. natalensis, (6) E. mossambica, (7) E. lindrothi, (8) E.
droebachiensis, (9) E. palermitana, (10) E. collaris, (11) E. lombricoides, (12) E. oerstedii, (13) E. annandalei, (14) E.
uncinata, (15) E. trinalis, (16) E. aucklandica, (17) E. insecta, (18) E. delineata.
2010a-b, 2012, 2013, 2015, 2016a-b, Fitzhugh et
al. 2015, Nogueira et al. 2010, 2013, 2017, 2018). If
possible, formal definitions of relevant taxa will
be presented, per the International Commission
on Zoological Nomenclature (1999) Article 13.1.1,
as referring to either phylogenetic or specific
hypotheses.
RESULTS
Systematics
Family Maldanidae Malmgren, 1867
Subfamily Euclymeninae Arwidsson, 1906
Genus Euclymene Verrill, 1900
Euclymene Verrill, 1900, p. 654–655; Arwidsson
1906, pp. 220–221, Day 1967, p. 134, Fauchald 1977,
p. 40, Salazar-Vallejo 1991, pp. 275–276, De Assis &
Christoffersen 2011, p. 242.
Type-species: Clymene amphistoma Lamarck,
1818: p. 341.
Definition: There is no phylogenetic
hypothesis to which Euclymene refers (cf.
Fitzhugh 2008) since this taxon denotes a
paraphyletic group. Thus, a formal definition of
the name cannot be provided at this time.
The following characters differentiate
individuals to which the name Euclymene refers
from individuals to which other Maldanidae
genera refer: body with 18–24 chaetigers;
1–2 acicular spines on first three chaetigers,
with smooth or dentate tips; cephalic plate
with deep or slight lateral notches; posterior
edge of cephalic plate smooth or crenulated;
notochaetae include limbate capillaries and
slender forms; uncini with 3–7 teeth above
rostrum; 1–4 pre-pygidial achaetous segments;
midventral cirrus longer than other cirri; anus
close to anal plate.
Remarks: The inability to define the name
Euclymene as representing a phylogenetic
hypothesis is due the fact that the taxon is
currently presumed paraphyletic; there are no
synapomorphies currently recognized (cf. Table
I). A future phylogenetic analysis involving
members of Euclymene species will be required
to resolve this issue.
Euclymene vidali sp. nov.
An Acad Bras Cienc (2022) 94(Suppl. 4) e20210283
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Table I. Comparative table to all genera of Euclymeninae. Note that some genera are not present exclusive characters. N/A = Not
applicable. * Heteroclymene is the unique taxon of Euclymeninae that species present acicular spine on chaetiger 4.
Genera
Characters
References
Cephalic
Glandular
Vascular
Acicular
Paired
rim
ventral
cirri on
# of
Cephalic Cephalic
spines, Chaetigers Circular
Campanulate lobules on
Anal
notches.
shield,
median/
Anal plug chaetigers/
plate
plate rim
chaetigers 1−3 uncini collar
chaetigers posterior
funnel
Lateral,
chaetiger
posterior
achaetigers
1−3
chaetigers
posterior
8
chaetigers
Aclymene
Weakly
Present
Buzhinskaj, 1995
developed
Present
Absent
Axiothella Verrill,
Well
Present
1900
developed
Present
Absent
Clymenella Verrill,
Well
Present
1873
developed
Present
Present
Well
developed;
weakly
Clymenura Verrill,
Present/
Present developed,
1900
absent
or some
times,
absent
Euclymene Verrill,
Well
Present
1900
developed
Eupraxillella
HartmannWell
Present
Schröder &
developed
Rosenlfelft, 1989
Gravierella
Fauvel, 1919
Present
Well
developed
Heteroclymene
Well
Present
Arwidsson, 1906
developed
Present
Present
Present,
Absent
Absent
Absent
Present
Absent
Absent
Present Present
Absent
Absent
Absent
Absent
Absent
Present
Absent
Absent
Absent
Absent
Present Present
Absent
Present
Absent
Yes
Absent
Absent
Absent
Imajima &
Present/ Present/
17−19/1−6 Shiraki 1982,
absent Absent
Read 2011
Present
Absent
Absent
Absent
Absent
Absent
Absent
Present
18−39/0−5
Day 1967,
Imajima &
Shiraki 1982
Absent
18−24/1−4
Arwidsson
1906, Day
1967
HartmannSchröder &
Rosenlfelft
1989
Present
Absent
Present
Absent
Absent
Present
Absent
Absent
Present Present
More tan
30/4
Present
Absent
Present
Absent
Absent
Present
Absent
Absent
Present
60−70/0
Day 1967, De
Assis et al.
2012
19/5
Arwidsson
1906,
Garwood
2007, Jirkov
2001
* Present,
on
Present
chaetigers
1−4
Absent
Absent
Absent
Absent
Absent
Absent
Present
Absent
Absent
Isocirrus
Well
Present
Arwidsson, 1906
developed
Present
Present
Absent
Absent
Absent
Absent
Absent
Absent
Present
Jonhstonia
Well
Present
Quatrefages, 1866
developed
Present
Present
Absent
Absent
Absent
Absent
Absent
Present
Present Present
Leiochone Grube,
Absent
1868
Absent
Absent
Present
Absent
Present
Absent
Absent
Absent
Absent
N/A
Day 1967,
Jiménez19−22/0−2
Cueto &
SalazarVallejo 1997
Absent
>3 uncini
Present
18/4
Buzhinskaja
1995, De
Assis et al.
2012
An Acad Bras Cienc (2022) 94(Suppl. 4) e20210283
4 | 22
Absent
SalazarVallejo 1991,
19−20/1−2
De Assis et
al. 2012
19−22/1−3
Mackie &
Gobim 1993,
De Assis et
al. 2012
Present/
19−29/1−5
absent
Read 2011,
De Assis et
al. 2012
JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Table I. Continuation.
Macroclymene
Verrill, 1900
Absent
Absent
Present
Absent
Absent
Present
Absent
31−40/0−1
Day 1967, De
Assis et al.
2012
Absent
Present on
Present
1−3
Absent
Absent
Absent
Absent
Absent
Absent
31−34/1
Augener
1926
Absent
Present on
chaetigers Absent
2−3
Absent
Absent
Absent
Absent
Present
Absent
19/2−3
Day 1967,
Detinova
1982
19/0−3
Arwidsson
1906,
Annekova
1937, De
Assis et al.
2012
38/0
Augener
1918, Green
1997
Weakly
developed
Present
Absent
Macroclyemenlla
Well
Present
Augener, 1926
developed
Present
Present
Maldanella
McIntosh, 1885
Present
Present
Weakly
developed
Present
Microclymene
Weakly
Present
Arwidsson, 1906
developed
Absent
Present
Absent
Absent
Absent
Absent
Absent
Absent
Absent
Petaloclymene
Augener, 1918
Present
Absent
Present
Absent
Absent
Absent
Absent
Absent
Present Present
Present
Well
developed
Present
Praxillella Verrill,
Well
Present
1881
developed
Present
Absent
Present
Absent
Absent
Absent
Absent
Present/
Absent
Present
absent
Pseudoclymene
Well
Present
Arwidsson, 1906
developed
Present
Absent
Present
Absent
Absent
Absent
Absent
Absent
ZooBank
Life
Science
I d e n t i f i e r ( LS I D ) - u r n : l s i d : z o o b a n k .
org:act:71ADFA40-55F8-42E8-B5D7-43015573A054.
(Figures 2a-f, 3a-f, 4a-b, 5a-d, 6a-d)
Johnstonia sp. De Assis & Christoffersen,
2011, p. 234, Figures 2, 3, 5, 6.
Material examined: Holotype: Brazil: Diogo
Lopes, Macau -Rio Grande do Norte, northeastern
Brazil, in tidal creek and mud (1.8–5.2 m). CIPYPOLY-UFPB 1745: José Eriberto De Assis and
André Vidal col., September 2007, (5°05´02.95” S;
36°27´13.50” W).
Paratypes: CIPY-POLY-UFPB 1746 (1 complete
specimen), (2) 1747, (5°04´27.23” S; 36°27´32.02”
W); CIPY-POLY-UFPB 1748, (3 complete specimens)
(4 anterior and posterior fragments) CIPY-POLYUFPB 1749: (5°04´55.01” S; 36°26´31.85” W); Barra do
Rio Mamanguape, Rio Tinto, Paraíba, tidal creek
and mud: CIPY–POLY–UFPB 1749 (5: 2 complete
specimens, 3 broken specimens): José Eriberto
De Assis, André Vidal, and Carmen Alonso Col.
January 2018 (6°46’04.07” S; 34°56’05.0” W).
Present Present
Garwood
2007,
18−19/3−4
Imajima &
Shiraki 1982
19/5
Definition: A specific hypothesis, accounting
for the following characters: presence of 23
chaetigers, cephalic plate with smooth posterior
margin, and serrate capillary chaetae on chaetiger
9 arranged as dense bundle. Hypothetically,
each of these characters arose among members
of an ancestral population, eventually becoming
fixed, resulting in individuals observed in the
present.
Description of adult semaphoronts: The
holotype is a complete specimen, length 50 mm,
1.5 mm wide. Paratypes 48‒62 mm long, 1.7‒2.0
mm wide. Body cylindrical; 23 chaetigers, one
pre-pygidial achaetous segment, one thinner
callus ring, pygidial funnel. Anterior end with
oval cephalic plate bordered by well-developed
cephalic rim. Cephalic rim smooth, with two
deep lateral notches and one posterior notch.
Prostomium broadly rounded, forming slightly
arched keel; about 10 red-brown ventrolateral
ocelli. Nuchal grooves parallel, extending
through three-quarters of cephalic plate length.
Mouth below prostomium, with wrinkled lower
An Acad Bras Cienc (2022) 94(Suppl. 4) e20210283
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Arwidsson
1906
JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 2. Euclymene vidali sp. nov. (a),
Anterior end showing the first four
chaetigers and mouth; (b) anterior end
showing first achaetigerous segment,
and peristomium; (c) Cephalic plate
showing nuchal grooves and length of
prostomium (Modified from De Assis
& Christoffersen 2011); (d) Parapodium
showing acicular spine and capillary
chaetae (Modified from De Assis &
Christoffersen 2011); (e) Parapodium from
chaetiger 9, showing modified serrate
capillary chaetae, and limbate capillary
chaetae; (f) Parapodium from chaetiger 15
showing spinose, and limbate capillaries
chaetae. Abbreviations: acha, achaetiger
head; as, acicular spine; cha, chaetigers;
cp, cephalic plate; sec, serrate capillary
chaetae; lic, limbate capillary chaetae;
spc, spinose capillary chaetae chaetae;
m, mouth; nc, notochaetae; ng, nuchal
groove; pe, peristomium; pr, prostomium;
sc, spinose capillary. Scales bars: (a) = 1
mm; (b) = 300 µm, (c, d, e, f) = 100 µm.
lip. Proboscis a smooth eversible sac (Figs. 2ac, 5a). Chaetigers 1–7 varying from 1.5‒2.0 mm
long, 1.5 mm wide. Chaetigers 8–9 two times
longer than anterior chaetigers; chaetigers 10–16
three times longer than first chaetiger; posterior
chaetigers decreasing in length. Notochaetae
emerge from depressions; neurochaetae project
directly from body wall on anterior half of
each segment (Fig. 2d-f). Remaining chaetigers
with small raised notopodia and conspicuous
neuropodial tori. Notopodia of chaetigers 1–23
with fascicles of long, fine capillary chaetae,
each with attached microalgal filaments.
Notochaetae of all chaetigers with posterior row
of long, sheathed capillaries, and anterior row
of shorter modified capillaries (Figs. 2e-f). These
chaetae have a short base and are of three
types: limbate; spinose; modified serrate (Figs.
3a-c, 6b-c). Chaetae on chaetiger 9 arranged in
dense bundle (Fig. 2e). Neuropodia of chaetigers
1–3 each with one acicular hook, with small
denticles above main fang (Figs. 3d, 6a). Posterior
to chaetiger 3, neuropodia with row of rostrate
hooks, present to chaetiger 23 (Figs. 3e-f); each
hook with rostrum surmounted by 4 smaller
denticles; single thick barbule, bent upwards,
present below rostrum. Hook rows arranged
perpendicular to body wall, with long, curved
posterior shaft, and prominent manubrium on
posterior half. Neuropodial tori with variable
number of rostrate hooks (4: 11, 5: 15, 6: 22) (Figs.
3e-f; 6d). Pre-pygidial segment about one half
length of last chaetiger, with reduced torus at
posterior end. Distinct callus ring in posterior
region of segment (Fig. 4a-b). Pygidial funnel
extended posteriorly, bearing 22 subconical anal
cirri of slightly variable length (paratypes with
19‒27); midventral cirrus two times longer than
other cirri. Anus terminal, central, surrounded
by divergent folds (Figs. 4a-b, 5d).
Live specimens dark red in anterior region,
light yellow in median and posterior regions.
Preserved specimens (in alcohol) uniformly
yellow. Tubes composed of sand, shells, fine
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 3. (a) Tufts of modified
serrate capillary chaetae from
chaetiger 9; (b-c) spinose and
limbate capillaries chaetae from
chaetiger of segment 15; (d) acicular
spine of first chaetigerous segment,
with denticulate tip; (e) Row of
rostrate uncini from chaetigerous
segment 15; (f) Rostrate uncini from
chaetigerous segment 15 showing
capitium, rostrum and barbules.
Abbreviations: as, acicular spine; b,
barbules; c, capitium, d, denticules;
sec, serrate capillary chaetae; lic,
limbate capillary chaetae; r, rostrum,
ru, rostrate uncini; sc, spinose
capillary chaetae. Scales bars: (a-f)
= 10 µm.
wood fragments, small stones, all adhered to
mucous matrix. Chaetigers 8–13 with strongly
marked stripes, neuropodial regions glandular,
arranged into four equidistant, longitudinal
glandular bands (one dorsal, one ventral,
two lateral). Dorsal glandular stripes extend
to chaetiger 13; ventral strips to chaetiger 14
(Fig. 5b). Low, rounded nephridial papillae
below posterior regions of neuropodial tori on
chaetigers 7–9 (Fig. 5c).
Distribution: Specimens live in sandy mud,
intertidal (type locality) to 1.8‒5.2 m depth.
Known only from Brazilian northeastern littoral,
for the Rio Grande do Norte and Paraíba States.
Etymology: The species name is after the
companion of the first author, André Vidal, who
assisted in the collection of material.
Remarks: Members of Euclymene vidali
sp. nov. differ from members of E. aucklandica
Augener, 1923, in that the latter has 21 chaetigers,
cephalic plate with crenulated posterior edge,
uncini with 4–5 teeth on the rostrum, and
midventral cirrus two times longer than other
anal cirri. Members of E. vidali sp. nov. differs
from members of E. coronata as the latter has 22
chaetigers, deep lateral notches, cephalic plate
with a strongly crenulated posterior edge, and
uncini with 3 teeth on the rostrum. Members of
other species of Euclymene differ from E. vidali
sp. nov. in having 2–4 pre-pygidial achaetigerous
segments, and the number of chaetigers (Table
II).
Key to species of Euclymene Verrill, 1900
1.
One
pre-pygidial
achaetous
segment………….…….....2
– More than one pre-pygidial achaetous
segment.…………………….….……...4
2. Midventral cirrus two times longer than
other anal cirri…....………………...…..3
– Midventral cirrus four times longer than
other anal cirri; 21 chaetigers; posterior edge of
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 4. (a) Posterior end of Euclymene vidali sp. nov. Showing the pre-pygidial achaetous segment and pygidium
(Modified from De Assis & Christoffersen 2011); (b) Anal funnel with sub-triangular cirri showing a long midventral
cirrus (Modified from De Assis & Christoffersen 2011). Abbreviations: ac, anal cirri; ppa, pre-pygidial achaetiger; ch,
chaetigers; cr, callus ring; mvc, medioventral cirrus; ne, neuropodium; nt, notopodium; p, pygidium. Scales bars: (a)
= 1 mm, (b) = 200 µm.
cephalic plate slightly crenulated; uncini with
4–5 teeth above rostrum……….……………………….E.
aucklandica Augener, 1923
3. Twenty-two chaetigers; deep lateral
notches; cephalic plate strongly crenulated edge;
uncini with three teeth above rostrum.………..……
E. coronata Verrill, 1900
– Twenty-three chaetigers; slight lateral
notches; cephalic plate with smooth edge; uncini
with four teeth above rostrum; midventral cirrus
two times longer than other anal cirri…………………
…………………………………..................…....….E. vidali sp. nov.
4. Two pre-pygidial achaetous
segments……………..................................................……..……5
– Three or more pre-pygidial achaetous
segments………........................................……………...……….14
5. Posterior edge of cephalic plate smoo
th….….............................................................……..……………….6
– Posterior edge of cephalic plate
crenulated….......................................................………….…..11
6. Less than 20 chaetigerous
segments……..........................................................…………….7
– Twenty-four chaetigers; uncini with 6–7
teeth above rostrum; midventral anal cirrus three
times longer than other cirri……E. luderitziana
Augener, 1918
7. Nineteen chaetigers………....................................8
– Eighteen chaetigers; midventral anal cirrus
four times longer than other cirri…………………………
…………...............................……….….E. dispar (Verril, 1873)
8. Midventral cirrus three times longer than
other anal cirri……….......................................…….…………..9
– Midventral cirrus two times longer than
other anal cirri……....................................………..…...……..10
9. Cephalic plate with slightly lateral and
posterior notches; uncini with four teeth above
rostrum………………………….E. trinalis Hutchings, 1974
– Cephalic plate with deep lateral and
posterior notches; uncini with five teeth above
rostrum…………....……..E. droebachiensis (Sars, 1872)
10. Cephalic plate with well-developed edge;
anal cirri all of similar length; uncini with five
teeth above rostrum……..…..E. natalensis Day, 1957
– Cephalic plate with low edge; anal cirri
alternating in length; uncini with 5–6 teeth above
rostrum…………………..…E. oerstedii (Claparède 1863)
11. Less than 20 chaetigers…................……..…….12
– Twenty-one chaetigers ...............................……...
...............................……....E. annandalei Southern, 1921
12. Nineteen chaetigers………..............……………..13
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 5. (a) anterior end of Euclymene vidali sp.
nov. showing the first chaetigerous segment and
prostomium with ocelli; (b) Median segments of
Euclymene vidali sp. nov. showing longitudinal
glandular strips; (c) Nephridial papillae from
chaetigerous segment 6; (d) Posterior end of
Euclymene vidali sp. nov. with one preanal
achaetigerous segment and pygidium. Abbreviation:
Np, nephridial papillae. Scales bars: (a and d) = 1 mm,
(b and c) = 300 µm.
– Ten chaetigers; cephalic plate with
slight lateral notches; posterior edge slightly
crenulated ……………………..E. delineata* Moore, 1923
13. Posterior edge of cephalic plate slightly
crenulated; with very small midventral anal
cirrus; other cirri short, subconical and of similar
length……….....E. uncinata Imajima & Shiraki, 1982
– Posterior edge of cephalic plate strongly
crenulated; first three chaetigers with 1–2
rostrate hooks; midventral anal cirrus two times
longer than other anal cirri, conical, of similar
length………………………….……E. mossambica Day, 1957
1 4 . T h re e p re - p y g i d i a l a c h a e to u s
segments…………………......................................................…15
– Four pre-pygidial achaetous segments;
cephalic plate slightly crenulated; midventral
anal cirrus two times longer than other anal cirri,
remaining cirri of similar length…….E. lindrothi
Eliason, 1962
15. Posterior edge of cephalic plate smoo
th…………….……….....................................................................16
– Posterior edge of cephalic plate crenulated;
midventral anal cirrus two times longer
than others similar lengths…..E. lombricoides
(Quatrefages, 1865)
16. Nineteen chaetigers……………..................…….17
– Twenty chaetigers; cephalic plate with
deep lateral notches; midventral anal cirrus
three times longer than other cirri………..E.
palermitana (Grube, 1840)
17. Cephalic plate with shallow notches;
uncini with five teeth above rostrum; midventral anal cirrus two times longer than other
cirri …….........................….E. insecta (Ehlers, 1905)
– Cephalic plate with strong lateral notches;
uncini with four teeth above rostrum; midventral
anal cirrus two times longer than other cirri
…………………………..……..….E. collaris (Claparède, 1869)
* Members of E. delineata were described
on the basis of anterior and posterior body
fragments, which indicates that the numbers
furnished do not represent the actual number
of chaetigers. The species is included in this
group since individuals have two achaetous
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Figure 6. Euclymene vidali sp. nov.
(a) Acicular spine from chaetiger 2;
(b) Limbate capillary from chaetiger
15; (c) Spinose capillary from
chaetiger 15, (d) Rostrate uncinus
from chaetiger 15. Scales bars: (a-d)
= 10 µm.
pre-pygidial segments and a crenulated
posterior edge of the cephalic plate.
DISCUSSION
Genera of Euclymeninae can be distinguished
by several characters, summarized in Table I.
Three monotypic genera are synonymized here:
Macroclymenella Augener, 1926, Eupraxillella
Hartmann-Schröder & Rosenlfelft, 1989, and
Pseudoclymene Arwidsson, 1906.
Members of Macroclymenella were described
as having 31‒34 chaetigers, one pre-pygidial
achaetiger, and a circular collar on chaetiger
4. The last character is unique for members of
Clymenella. Yet, the number of chaetigers among
members of Clymenella varies between 18 and
39, and there are 0 to 5 pre-pygidial achaetigers
(Table II). In fact, the presence of a circular collar
on chaetiger 4 indicates that Macroclymenella
is a junior synonym of Clymenella, and thus,
M. stewartensis Augener, 1926, must thus be
recognized as Clymenella stewartensis comb.
nov.
Members of Eupraxillella HartmannSchröder & Rosenlfelft, 1989, were described
with 30 chaetigers, four pre-pygidial achaetigers,
a pygidium with a short edge, and with a ring
of cirri; anus on the cone, with anal ventral
valve. The form of the pygidium (with an anal
pore located over the cone), and anal valve are
typical for members of Praxillella. The number
of chaetigers among members of Praxillella
varies from 18 to 19, and there are 3‒4 prepygidial achaetigers. Based especially on the
pygidium, position of the anus and anal valve,
Eupraxillella is a junior synonym of Praxillella,
and Eupraxillella antarctica Hartmann-Schröder
& Rosenlfelft, 1989, must be recognized as
Praxillella antarctica com. nov.
Pseudoclyemene Arwidsson 1906 was
erected on the basis of the length of the nuchal
grooves. This is a unique character for the
genus. However, members of this species have a
pygidium with a short edge, and a ring of cirri of
different lengths; the anus is located on the cone.
Although Arwidsson (1906) does not describe the
presence of an anal valve, the original figures
resemble typical specimens of Praxillella. In this
case, we recognize Pseudoclyemene as a junior
synonym of Praxillella, and P. quadrilobata
Arwidsson, 1906, must be recognized as
Praxillella quadrilobata com. nov.
Members of Euclymene africana (Gravier
1905, p. 198–201, Figs. 214–216), and E. watsoni
(Gravier 1905, p. 201–203, Figs. 2017–2219) were
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JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Table II. Comparative table of Euclymene species that have midventral cirrus longer than other anal cirri. The
sequence of species is according to the number of pre-pygidial achaetigerous segments.
Species
Cephalic plate
border
E. aucklandica
Augener, 1923
Deep lateral
notches; posterior
crenulated
E. coronata Verrill,
1900
Deep lateral
notches; posterior
strongly crenulated
E. vidali sp. nov.
Slight lateral
notches, 1
posterior notch;
smooth edge
E. annandalei
Southern, 1921
Slight lateral
notches;
crenulated edge
Slight lateral
E. delineata Moore, notches; posterior
1923
edge slightly
crenulated
No. of preUncini
No. of
pygidial
apical
chaetigers achaetteeth
igers
21
22
23
21
10
1
1
1
2
2
4–5
Anal funnel cirri
Midventral cirrus
4 times longer
New Zealand,
than other cirri of Auckland Islands
different lengths
3
Midventral cirrus
2 times longer
than other cirri;
triangular cirri
alternating lengths
4
Midventral cirrus
2 times longer
Diogo Lopes,
than other cirri; Macau, Rio Grande
subequal triangular do Norte, Brazil
cirri
Augener 1923,
Glasby et al. 2009
Verrill 1900, Jones
Bermuda to
et al.
Northeastern
1986, JiménezCaribbean;
Cueto & Salazarnortheastern
Vallejo 1997, De
Brazil, João Pessoa,
Assis et al. 2012,
Paraíba Brazil
Amaral et al. 2013
Rio Mamangua
Southern 1921,
Day 1967
4
Midventral cirrus
one third length of Santa Rosa Island,
anal cup; other cirri California, USA
of similar length
Type locality
Moore 1923
Type locality
Verrill 1873,
Arwidsson 1906
Type locality
Arwidsson 1906,
Jirkov 2001,
Amaral et al. 2013
18
2
?
E. droebachiensis
(Sars, 1872)
Slight lateral
notches; posterior
edge smooth
19
2
5
Midventral cirrus 3
times longer than
others; shorter cirri
of different lengths
E. luderitziana
Augener, 1918
Slight lateral
notches, and 1
posterior notch;
smooth edge
6–7
Midventral cirrus
3 times longer
than remaining
cirri, which are of
different lengths
E. mossambica (Day,
1957)
Slight lateral
notches;
crenulated edge
6
Midventral cirrus 2
times longer than
other, triangular
cirri, that alternate
in length
2
Type locality
Tropical Indian
Ocean
5–6
Midventral cirrus
2 times longer
than other cirri,
triangular cirri of
same length
E. díspar (Verrill,
1873)
19
References
This paper
Midventral cirrus 4
times longer than
other cirri; shorter
cirri of different
lengths
2
Castle Island
Boston, USA
Distribution
pe, Rio Tinto,
Paraíba, Brazil
Slight lateral
notches; posterior
edge smooth
24
Type Locality
Chilka Lake, India
Massachusetts, USA
Faeroe, Iceland
Southwest Africa,
Lambert’s Bay,
Augener 1918, Day
South Africa, Cape
Lüderitzbucht,
1955, 1967
Namibia
Mozambiqueque Is., South
Africa
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Type locality
Day 1957, 1967
JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
Table II. Continuation.
E. natalensis (Day,
1957)
E. oerstedii
(Claparède 1863)
Slight lateral
notches; smooth
edge
Slight lateral
notches; smooth
edge
Slight lateral
E. trinalis Hutchings,
notches; posterior
1974
edge smooth
Deep lateral
E. uncinata Imajima
notches; posterior
& Shiraki, 1982
edge crenulated
E. collaris
(Claparède, 1869)
Without lateral
notches; a deep
posterior incision
E. insecta (Ehlers,
1905)
Slight lateral
notches; posterior
edge smooth
E. lombricoides
(Quatrefages, 1865)
Slight lateral
notches;
crenulated edge
Slight notches
E.
lateral, and deep
palermitana (Grube,
posterior notch;
1840)
posterior edge
smooth
Slight lateral
E. lindrothi Eliason, notches; posterior
1962
edge slightly
crenulated
19
19
19
19
19
19
19
20
19
2
2
2
2
3
3
3
3
4
6
Midventral cirrus
Inhaca Island,
slightly longer than
Cape Region and
Delagoa Bay City
cirri of alternating
Natal, South Africa:
lengths
Normandy,
Atlantic Ocean
North Sea and
English Channel,
Mediterranean,
South America,
Brazil; Western
Africa Japan
4
Midventral cirrus
4 times longer
than other cirri;
triangular, of
similar length
South of Godwin
Is., Wallis Lake
NSW
New South Wales
(Marimbula, Jervis
Bay, Port Hacking,
Botany Bay, Lake
Macquarie, Port
Stephens)
6
Midventral cirrus 2
times longer than
other cirri; very
small; others short,
subtriangular, of
similar length
Kashima Sea,
Japan
5–6
Midventral cirrus 2
times longer than
other cirri that
alternate in length
4
Midventral cirrus
2 times longer
than other cirri; of
similar length
5
Midventral cirrus
slightly longer
Chatham Island,
than other anal
New Zealand
cirri, with different
lengths
Gulf of Naples,
Italy
Midventral cirrus 2
Boulogne-Sur-Mer
times longer than
5–6
and Calais beach,
other cirri that
France
alternate in lengths
5
5–6
Midventral cirrus 3
times longer than
others cirri, other
cirri of different
lengths
Palermo, Italy,
Mediter-anean
Midventral cirrus
2 time longer
North Atlantic,
than other cirri; Geounit Skagerrak
cirri with different
Strait.
lengths
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Day 1957, 1967
Fauvel 1927, Day
1967, Imajima &
Shiraki 1982
Hutchings 1974,
Hutchings &
Murray 1984
Known only from Imajima & Shiraki
type locality
1982
Northeastern
Atlantic: North
America
Claparède 1869,
and Canada;
Arwidsson 1906,
Northwestern
Fishelson &
Atlantic: Portugal
Rullier 1969,
and Spain;
Brunel et al. 1998
Mediterranean: Italy
and Greece; Rea Se
Type locality
Ehlers 1905,
Hartman 1959,
Glasby et al. 2009,
Liu 2008
North Atlantic,
Quatrefages 1865,
Scotland,
Fauvel 1927, Day
English Channel
1967, Imajima
to Morocco;
& Shiraki 1982,
Mediterranean Sea Amaral et al. 2013
North Atlantic,
Grube 1840,
Portugal and Spain; Orlandi 1898,
France, Monaco;
Arwidsson 1906,
Italy, Naples; Africa,
Fauvel 1927,
coast of Tunisia.
Bellan 2001
Type locality
Eliason 1962,
Bellan 2001
JOSÉ ERIBERTO DE ASSIS et al.
A NEW Euclymene FROM THE SOUTHWESTERN ATLANTIC
originally described from Djibouti, Gulf of
Aden, East Africa. In the original descriptions
and illustrations, the specimens presented
a pygidium with an anal funnel bordered by
several anal cirri of equal length. This condition
is part of what characterizes members of
Isocirrus (Arwidsson 1906, Salazar-Vallejo 1991,
De Assis & Christoffersen 2011, De Assis et al.
2012). From both the text and figures, it is clear
that members of the species do not present
a midventral cirrus that is longer than the
remaining cirri, a condition that is part of the
definition of Euclymene. Therefore, these species
are herein transferred to Isocirrus: I. africana
(Gravier, 1905) comb. nov., and I. watsoni (Gravier,
1905) comb. nov.
Comments on monophyly of Euclymeninae:
In their inferences of phylogenetic hypotheses
e x p l a i n i n g m o r p h o l o g i c a l c h a ra c t e r s
among members of Maldanidae, De Assis &
Christoffersen (2011) found Euclymeninae
to be monophyletic. Kobayashi et al. (2018)
subsequently inferred phylogenetic hypotheses
for only sequence data and obtained a
paraphyletic Euclymeninae due to members
of Nicomachinae within the former clade.
Based on their results, Kobayashi et al. (2018)
concluded that the morphological characters
used by De Assis & Christoffersen (2011) are not
synapomorphies for Euclymeninae. We will first
comment on inherent limitations to inferring
phylogenetic hypotheses for sequence data,
the error of relying on phylogenetic hypotheses
for sequence data as the means of determine
explanatory hypotheses for other classes of
characters, then address those characters that
establish monophyly of Euclymeninae.
It has become fashionable in polychaete
systematics to focus on inferences of phylogenetic
hypotheses based only on sequence data (e.g.
Struck et al. 2011, 2015, Borda et al. 2012, Glasby
et al. 2012, Goto et al. 2013, Weigert et al. 2014,
Aguado et al. 2015, Goto 2016, Weigert & Bleidorn
2016, Kobayashi et al. 2018, Nygren et al. 2018,
Langeneck et al. 2019, Shimabukuro et al. 2019,
Alves et al. 2020, San Martín et al. 2020, Stiller
et al. 2020, Tilic et al. 2020), and often to then
comment on other classes of characters in
relation to those hypotheses, typically through
the process called ‘character mapping.’ Two
significant, interrelated problematic questions
arise with these approaches: can inferences
of phylogenetic hypotheses causally account
for sequence data, and can other classes of
characters be explained through mapping on
the basis of those inferred hypotheses? Indepth treatments of these topics can be found
for instance in Fitzhugh (2014, 2016a), so only a
brief overview will be presented here.
In accordance with the goal of scientific
inquiry, which is to obtain causal understanding
(e.g. Hanson 1958, Hempel 1965, Rescher 1970,
Popper 1983, 1992, Salmon 1984, Van Fraassen
1990, Strahler 1992, Mahner & Bunge 1997,
Hausman 1998, Thagard 2004, Nola & Sankey
2007, de Regt et al. 2009, Hoyningen-Huene 2013,
Potochnik 2017, Currie 2018, Anjum & Mumford
2018), we regard this as the intent of inferring
both specific and phylogenetic hypotheses.
While it is common in systematics to claim that
the purpose of inferring such hypotheses is to
obtain ‘the phylogeny’ for a particular group
of organisms, this is something of a misnomer,
just as it is erroneous to say one has inferred
a ‘molecular phylogeny.’ Inferring explanatory
hypotheses that causally account for a set of
differentially shared characters (cf. Fitzhugh
2006a, 2008b, 2009, 2012, 2013, 2016a-c), implied
by cladograms, cannot be equated with being ‘a
phylogeny’ much less ‘the phylogeny.’ The term
phylogeny incorrectly connotes that one can
attain comprehensive explanatory constructs
regardless of the number of observations
used to infer those constructs. This, along
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JOSÉ ERIBERTO DE ASSIS et al.
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with not acknowledging the requirement of
total evidence (Fitzhugh 2006b), has led to the
tendency to only infer phylogenetic hypotheses
from sequence data and assume, incorrectly,
that those hypotheses extend to other observed
characters. This does not work because the
reasoning involved in producing explanatory
hypotheses only pertains to the characters
involved in inferring those hypotheses. Other
characters in need of explanation should not be
excluded simply out of conformity with uncritical
or popular methodological trends.
Computer algorithms for inferring
phylogenetic hypotheses are entirely agnostic
with regard to what causal mechanisms
contribute to fixation of novel characters among
individuals in ancestral populations or the
nature of population splitting events (Fitzhugh
2016a). This does not present problems when
explaining morphological characters since at
a minimum either natural selection or genetic
drifts are possible causes of fixation. When
considering sequence data, however, drift can
directly explain shared nucleotides or amino
acids; but selection does not operate at the
level of those molecules since they have no
direct emergent properties that manifest fitness
differences among individuals. Instead, selection
occurs at higher organizational levels and
indirectly affects intergenerational occurrences
of associated nucleotides and amino acids; a
phenomenon known as downward causation
(Campbell 1974, Vrba & Eldredge 1984, Salthe
1985, Lloyd 1988, Ellis 2008, 2012, 2013, Auletta
et al. 2008, Jaeger & Calkins 2011, Ellis et al. 2011,
Laland et al. 2011, Martínez & Moya 2011, Davies
2012, Okasha 2012, Walker et al. 2012, Griffiths
& Stotz 2013, Martínez & Esposito 2014, Walker
2014, Fitzhugh 2016a, Mundy 2016, Callier 2018,
Pouyet et al. 2018, Salas 2019, Yu et al. 2020).
While it would be unrealistic to explain all
sequence data by way of drift, invoking selection
first requires associating those sequence data
to be explained, via downward causation, with
morphological characters upon which selection
has been hypothesized as operative. If such an
association is available, then those relevant
sequence data would be excluded from the data
matrix used to infer phylogenetic hypotheses,
since those characters already would be
accounted for via downward causation by the
morphological characters. In the absence of
evidence for discriminating sequence data to be
explained by drift or downward causation, the
only viable option is to acknowledge that those
data should be excluded from phylogenetic
inferences. For these reasons, we do not regard
the phylogenetic hypotheses presented by
Kobayashi et al. (2018) to be plausible or provide
a basis for concluding that Euclymeninae is
paraphyletic.
The second problem related to inferences
of phylogenetic hypotheses from sequence data
is the popular tactic of considering additional
phylogenetic hypotheses of morphological
characters through what is called ‘character
mapping’ (cf. Fitzhugh 2014). For instance,
Kobayashi et al. (2018) mapped the absence and
presence of cephalic and anal plates onto tree
topologies they obtained for sequence data,
and then proceeded to discuss phylogenetic
hypotheses accounting for these characters.
Mapping, however, does not lead to results that
can be interpreted as legitimate explanatory
hypotheses. The reason is because the act
of ‘optimizing’ characters on a previously
inferred tree topology, i.e. a set of explanatory
hypotheses for a set of characters used to infer
those hypotheses, is not an action that can
be interpreted as an epistemically meaningful
inference. Inferring phylogenetic hypotheses
involves a form of non-deductive reasoning
known as abduction (Peirce 1931, 1932, 1933ab, 1934, 1935, 1958a-b, Hanson 1958, Fann 1970,
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Reilly 1970, Thagard 1988, Josephson & Josephson
1994, Magnani 2001, 2009, 2017, Psillos 2002, 2011,
Walton 2004, Gabbay & Woods 2005, Aliseda
2006, Schurz 2008, Park 2017, for considerations
of abduction in relation to systematics see
Fitzhugh 2006a-2006b, 2008, 2009, 2010a, 2012,
2013, 2014, 2015, 2016a-b). At a minimum, the
premises of an abductive inference involve the
conjunction of some causal theory(ies) and
effect(s) to be explained. The conclusion is
an explanatory hypothesis stating past causal
conditions accounting for observed effects.
Phylogenetics computer algorithms serve as
surrogates for human abductive reasoning, albeit
under incorrect monikers such as ‘parsimony,’
‘maximum likelihood,’ and ‘Bayesian’ (Fitzhugh
2012, 2016a). Character mapping is not a form of
abductive reasoning since the premises of such
an ‘inference’ would only include a previously
inferred tree topology and subsequent
characters to be explained. In the absence of
any actual or implied evolutionary theory(ies)
involved in the inference, or the inclusion of all
observed characters as part of the premises, per
the requirement of total evidence, the conclusion
of mapped characters cannot be interpreted as
indicating past causal conditions. As such, the
evolutionary considerations of cephalic and
anal plates by Kobayashi et al. (2018) cannot be
regarded as epistemically sound.
W i t h t h e fo re go i n g o v e r v i e w, t h e
synapomorphies for Euclymeninae called into
question by Kobayashi et al. (2018) can be
reviewed. Regarding nuchal grooves, members
of species of Maldanella, including M. harai
Izuka, 1902, have straight and parallel nuchal
groves according to Detinova (1982, p. 66, Fig.
2a-d). Interestingly, one specimen of M. harai
described and illustrated from Japanese waters
by Imajima & Shiraki (1982, p. 55, Fig. 25b) had
strongly curved nuchal grooves, in contrast to
the description and illustration of Detinova
(1982). Members of species of Clymenella,
including C. complanata Hartman, 1969, have
straight, parallel nuchal grooves. A specimen of
C. complanata reported from Japan presented
short and curved nuchal grooves (Imajima &
Shiraki 1982, p. 48, Fig. 20b), contradicting the
original description of Hartman (1969, p. 435,
Fig. 2). For both cited species, we suggest they
are new species, but only with examinations of
material we can confirm this opinion.
Straight, parallel nuchal grooves have been
illustrated with details for all Euclymeninae
in several important systematics papers in
the literature on Maldanidae (Pilgrim 1977,
Arwidsson 1906, Fauvel 1927, Day 1967, Fauchald
1977, Imajima & Shiraki 1982, Lee & Paik 1986,
Salazar-Vallejo 1991, Jiménez-Cueto & SalazarVallejo 1997, Mackie & Gobin 1993, De Assis &
Christoffersen 2011, De Assis et al. 2012) (Table I).
Curved or J-shaped nuchal grooves have been
found in Rhodininae, Notoproctinae, Maldaninae
and Nicomachinae (Arwidsson 1906, Day 1967,
De Assis & Christoffersen 2011, De Assis et al.
2012). It is possible that the straight, parallel
nuchal grooves had reverted in punctual species
of Euclymeninae, but it does not seem very
clear. The most important here is that straight
nuchal grooves arise as a synapomorphy to
Euclymeninae.
Subsequent authors (Pilgrim 1977, Hausen
& Bleidorn 2006, Tilic et al. 2015), dealing with
ontogeny and morphology, presented more
detailed characters for Euclymeninae: 1) a
double row of notochaetae parallel to the
antero-posterior body axis from chaetiger 13
onwards, and 2) a straight chaetal sac visible
from chaetiger 13 in adults, in contrast to an
involute chaetal sac. A transverse notopodial
double row of chaetae represents the primary
condition in Maldanidae (Tilic et al. 2015). The
stepwise transition between both conditions
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JOSÉ ERIBERTO DE ASSIS et al.
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can always be seen in chaetigers 11 and 12 (Tilic
et al. 2015, De Assis & Christoffersen 2011).
The presence of a callus ring preceding
the anal funnel is a unique character among
members of Euclymeninae (Garwood 2007). This
character was not discussed by Kobayashi et al.
(2018).
The presence of a terminal anus, enclosed
within an anal funnel, and covered by a plate,
is a unique character for Euclymeninae and
Nicomachinae (Fauvel 1927, Fachauld 1977
Day 1967, Imajima & Shiraki 1982, De Assis &
Christoffersen 2011, De Assis et al. 2012). Whether
Nicomachinae may represent a taxon included
within Euclymeninae, as suggested by Kobayshi
et al. (2018), needs to be more thoroughly
investigated. Although a cephalic plate has been
lost among members of Nicomachinae and some
Leiochone, the anal plate is a synapomorphy
for the clade Notoproctinae + Maldaninae +
Euclymeninae + Nicomachinae.
In summary, straight, parallel nuchal
organs, double rows of notochaetae parallel to
the antero-posterior body axis from chaetiger
13 onwards, chaetal sacs visible from chaetiger
13 in adults, a callus ring preceding the anal
funnel, and the anus on an anal plate that is
sunk into the anal funnel, are all characters
that support the monophyly of Euclymeninae.
A more extensive future phylogenetic analysis
of Maldanidae will consider those characters
establishing monophyly of the remaining
subfamilies.
Comment on the status of the taxon
‘Maldanoplaca’
In their phylogenetic study of Maldanidae,
De Assis & Christoffersen (2011: Table 3, Fig. 7)
introduced the unranked name Maldanoplaca
for the clade, (Notoproctinae (Maldaninae
(Nicomachinae, Euclymeninae))). Unfortunately,
this name was not accompanied by a definition
as required by Article 13.1.1 of the International
Code of Zoological Nomenclature (International
Commission on Zoological Nomenclature
1999). As such, the name Maldanoplaca can
only be regarded as an informal placeholder
for the phylogenetic hypotheses accounting
for characters associated with that clade. We
therefore suggest that the name ‘Maldanoplaca’
should no longer be referred to as a formal
taxon name. As such, the name can be ignored.
Acknowledgments
We heartily thank Dr. Carmen Alonso for her dedication
in preserving zoological specimens in the Laboratório de
Invertebrados Paulo Young (LIPY), and for the sampling
of material. We acknowledge Dr Martin Schwentner,
from the Center of Natural History, Universität Hamburg
- Zoologisches Museum, for sending us the photo of
material from the Museum. We acknowledge Karen Green
for valuable suggestions on the manuscript. We thank
CNPq for a productivity grant to M.L. Christoffersen, and
FACEPE Fundação de Amparo a Ciência e Tecnologia de
Pernambuco for a post-doctoral scholarship to J.E. De
Assis (DCR-0086–2.04/13).
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JOSÉ ERIBERTO DE ASSIS1
https://orcid.org/0000-0002-1522-2904
JOSÉ ROBERTO BOTELHO DE SOUZA2
https://orcid.org/0000-0002-0144-3992
KIRK FITZHUGH3
USA: Clarendon Press, 231 p.
https://orcid.org/0000-0002-1366-2260
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https://orcid.org/0000-0001-8108-1938
1
Prefeitura Municipal de Bayeux, Departamento de Educação
Básica, Rua Santa Tereza, 600, 58306-070 Bayeux, PB, Brazil
2
Universidade Federal de Pernambuco, Centro de
Biociências, Departamento de Zoologia, Av. Prof.
Morais Rego, 1235, 50670-901 Recife, PE, Brazil
3
Natural History Museum of Los Angeles County, 900
Exposition Blvd, 90007 Los Angeles, California, USA
4
Universidade Federal da Paraíba, Centro de Ciências Exatas
e da Natureza, Departamento de Sistemática e Ecologia,
Cidade Universitária, 58059-900 João Pessoa, PB, Brazil
Correspondence to: José Eriberto de Assis
E-mail: eri.assis@gmail.com
Author contributions
JEDA did field collections and drafted the manuscript, performed
the all images; JRBS, KF and MLC write, read and approved the
final manuscript.
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tree using transcriptomics. Mol Biol Evol 31: 1391-1401. Doi:
10.1093/molbev/msu080.
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