Petaloclymene pacifica, a new genus and species of Maldanidae (Annelida: Polychaeta)

5 Pages·1997·0.28 MB·

BULLETIN Of MARINESCIENCE. 60(2):235-239. 1997
PETAL 0CLYMENE PACIFICA, A NEW GENUS AND SPECIES OF
MALDANIDAE (ANNELIDA: POLYCHAETA)
Karen D. Green
ABSTRACT
Peta/oc/ymene pacifica (Polychaeta: Maldanidae) is described from waters off southern
California. Most characters of the new genus and species are typical of the subfamily Eucly-
meninae. The anal plaque is unique in being asymmetrical, similar to that of Peta/oproctus
quatrefllges. 1865 of the subfamily Nicomachinae. Presence of a cephalic plaque and axial
proboscis indicate that Peta/oc!ymene is a member of Euclymeninae as opposed to Nico-
machinae.
During monitoring studies (1984-1994) off southern California, anterior frag-
ments of an unique euclymenin and posterior fragments of what appeared to be a
new species of Petaloproctus quatrefages, 1865 were periodically collected at the
same sampling locations. Collection of acomplete specimen revealed that the mis-
matched fragments were from the same species, which is described herein.
The subfamily Euclymeninae is defined as including maldanids that possess
both cephalic and anal plaques, and have a terminal anus (Fauchald, 1977 after
Arwidsson, 1907). Typically the margin of the anal plaque is symmetrical, encir-
cling a centrally located terminal anus or projecting anal cone.
The new species differs from all described euclymenins in having an asym-
metrical anal plaque that is obliquely oriented on the pygidium, and the terminal
anus is located closer to the ventral margin of the plaque. A new genus is pro-
posed for the species based on the characteristics of the anal plaque.
MATERIALS AND METHODS
Specimens were collected by Van Veen grab during monitoring programs off Los Angeles, Long
Beach. Newport Beach, and San Diego, California between 1984and 1994.Examined specimens were
from collections of the City of Los Angeles Hyperion Treatment Plant, City of San Dicgo Treatment
Plant, County Sanitation Districts of Orange County, MEC Analytical Systems, Inc., and Southern
California Coastal Water Research Project. All specimens have been deposited in the Los Angeles
County Museum-Allan Hancock Foundation polychaete collection (LACM-AHF).
Drawings were prepared with the aid of acamera lucida and from photographs. Methyl green stain
was used to highlight epidemlal glandular areas, whereby specimens were immersed in a strong so-
lution of stain in 70% alcohol and then placed in clean alcohol to leach excess stain. Longitudinal
dissections of the head region and body were made to examine the proboscis musculature. internal
septa, and nephridia. Neurosetae were counted on each setiger. Dissections were made of Peta/oproc-
illS socia/is Andrews. 1891 (LACM-AHF, n1721) for comparison with the new genus.
SYSTEMATICS
Petaloclymene new genus
Diagnosis.-Cephalic plaque with raised margins. Prostomial palpode narrow. Nu-
chal organs nearly straight, parallel. Axial proboscis without ventral muscle bulb.
Four internal septa separate setigers 1-5. Paired nephridiopores on ventrum of
setigers 7-9. Asymmetrical anal plaque, plaque margin dorsally reduced. Dorsal
attachment of plaque margin near junction of last setiger, margin increasingly sepa-
rated from junction of last setiger proceeding ventrally. Anus terminal, near ven-
tral margin of plaque. Notosetae and neurosetae on all setigers. Notosetae include
bilimbate and haired capillaries. Neurosetae rostrate uncini with apical teeth in
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236 BULLETIN OFMARINE SCIENCE, VOL. 60. NO,2, 1997
vertical series above main fang, and with subrostral hairs below main fang, un-
cini in single rows. Epidermal glands best developed in head region and setigers
1-8.
Remarks,-Petaloclymene isreferred to the subfamily Euclymeninae based on the
presence of both cephalic and anal plaques and a terminal anus. Petaloclymene is
most similar to genera such asAxiothella Verrill 1900,which have rostrate uncini
on setigers 1-3 rather than acicular spines. The asymmetrical anal plaque distin-
guishes Petaloclymene from all described euclymenins.
The anal plaque is similar to Petaloproctus of the subfamily Nicomachinae.
Other described euclymenins andNicomache of the subfamily Nicomachinae both
have symmetrical anal plaques with a terminal anus (Imajima and Shiraki, 1982).
The similarity between the asymmetrical anal plaque of the new genus and that
of Petaloproctus, as well as the similarity between the symmetrical anal plaques
of other euclymenins and Nicomache suggests a relatively close phylogenetic re-
lationship between euc1ymeninsand nicomachins.
Euclymenins (including Petaloclymene) differ from nicomachins in having a
cephalic plaque. Although internal anatomy has been examined for only a few
maldanids, results indicate a difference in the proboscides of euclymenins and
nicomachins. Petaloclymene and members ofAxiothella Verrill 1900,Clymenclla
Verrill 1873, Euclymene Verrill 1900, and Praxillella Verrill 1881 have an axial
proboscis (Pilgrim 1966;Kudenov 1977;Tzetlin, 1991).Dissection ofPetaloproc-
tus socialis revealed aventral proboscis. Nicomache lumbricalis (Fabricius, 1780)
and N. minor Arwidsson, 1907 also have a ventral proboscis (Tzetlin, 1991).The
external and internal differences of thehead region ofeuclymenins and nicomach-
ins support the placement of Petaloclymene in the subfamily Euclymeninae.
Type Species.-Petaloclymene pacifica, here designated.
Etymology.-Petaloclymene is a combination of Petaloproctus and Euclymcnc to
highlight that the new genus shares characters in common with these genera.
Petaloclymene pacifica new species
Figure lA-K
Material Examined.-PACIFIC OCEAN, southern California: outer Los Angeles harbor, Los Angeles
Terminal Island Plant, Station HC4, 12m, 31August 1994, holotype (LACM-AHF POLY 1730); off
Long Beach, survey 9502, Station B13, replicate 1, 10 m, 58 anterior fragments, 7 posterior frag-
ments, paratypes (LACM-AHF POLY 1731); off Long Beach, survey 9502, Station B13, replicate 2,
15m, 66 anterior fragments (LACM-AHF); off Point Loma, San Diego, City of San Diego Treatment
Plant, Station A-2, 3April 1984, 60 m, 1specimen (LACM-AHF); off Newport Beach, County Sani-
tation Districts of Orange County, CSDOC voucher 0001301, survey 9388, Station 35, rep 1,29 m,
23 anterior fragments (LACM-AHF); Santa Barbara Channel, off Carpinteria, SCCWRP voucher
0004695,22 August 1994, Station 0499, 122 m, 9 anterior fragments (LACM-AHF).
Description.-Body long, cylindrical, with 38 setigers. The complete holotype is
about 40 mm long and 0.2-0.7 mm wide. Posterior end of holotype apparently
regenerated because segments substantially reduced in size after setiger 16; pos-
terior end after setiger 32 tom, in fragile condition. Paratype anterior and poste-
rior fragments (not regenerated) used for illustrations to avoid damage to holo-
type. Paratype anterior fragments range in size, for 13setigers, from 6 mm long
by 0.2 mm wide to 19mm long by 0.7 mm wide. Some anterior fragments with
eggs (0.13-0.15 mm in diameter). Specimens lack pigmentation in alcohol.
Head with cephalic plaque (Fig. lA, B), margin smooth and slightly incised
posterolaterally. Nuchal organs parallel, long, extending to lateral incisions of ce-
GREEN: Pt.7ALOCLYMENE PAC/PlCA, ANEW MALDANlDAE (POLYCHAETA) 237
B
G
H
I •
H
E F
Figure I, Petaloclymene pacifica n.sp. (paratype LACM-AHF POLY): A,Anterior end, lateral view;
B, Cephalic plaque, top view; C, Anal plaque and last three setigers, lateral view; D, Anal plaque,
dorsal view; E, Notosetae, setiger I; F,Notosetae, setiger 12;G, Magnification of portion of shaft of
haired capillary, setiger 12;H, Neuropodial uncinus, setiger 1;I, Neuropodial uncinus, setiger 12; J,
Anterior nine setigers, dorsal view; K, Anterior nine setigers, ventral view (shading on J and K indi-
cate methyl green staining) (Line scales: body, 1.0mm, setae 0.1 mm).
238 BULLETINOFMARINESCIENCE, VOL.60,NO.2, 1997
phalic margin, Prostomial palpode narrow, rounded, Mouth ventral with protrud-
ing, semicircular lower lip. Axial, tube-like proboscis without ventral muscle bulb.
Everted proboscis with cuticularized and papillated buccal mass, finely ciliated
esophagus. Ocelli located ventrolaterally below cephalic margin.
Pygidium obliquely oriented with well-developed anal plaque (Figs. 1C, D).
Margin of plaque well developed, smooth to slightly crenulate. Margin dorsally
reduced. Attachment of plaque margin asymmetrical on pygidium; dorsal attach-
ment closer tojunction of last setiger, increasingly separated from junction as mar-
gin proceeds ventrally. Holotype with regenerated asetigerous rings between last
setiger and plaque. No asetigerous preanal segments on non-regenerated paratypes
(Fig. IC). Anus terminal, near ventral margin of plaque. Anus with anal plug.
Four internal septa separate setigers 1-5. Paired nephridiopores open on ven-
trum of setigers 7-9.
Junction between segments distinct on setigers 1-7. Setae in anterior half of
segment in setigers 1-7. Junction between setigers 8 and 9 may be indistinct. Se-
tae positioned posteriorly from setiger 9 onwards. Setigers 17-38 short and re-
generated in holotype.
Notosetae emerge from sunken pits on setigers 1-3, thereafter from raised pads,
most distinct after setiger 5. Notosetae of setigers 1-8 include bilimbate sheathed
capillaries (Fig. 1E). Slender, "haired" setae present in addition to sheathed cap-
illaries from setiger 9 (Fig. IF, G).
Neurosetae consist of rostrate uncini with subrostral hairs below main fang.
Teeth above main fang in vertical series, number of teeth increase from 3 on se-
tiger 1 (Fig. 1H) to 6 (Fig. 11)as progress along body. Specimens 0.7 to 0.9 mm
wide with 1-4 uncini in setigers 1to 3, 7-12 uncini in setigers 4 to 16, and 1-5
uncini in more posterior setigers. Only 1-3 uncini on last three setigers of most
posterior ends.
Epidermal glands most developed in head region and setigers 1-8, and mainly
limited to neuropodial tori after setiger 8. Uptake of methyl green stain in ante-
rior setigers indicated by shading in Figures 1J, K. Intensity of stain varies along
body. Stain darkest on peristomium, presetal region of setiger 3, and ventrum of
setiger 8 between neuropodial tori. Although not as dark as on setiger 3, dark
stain also occurs in presetal region of setigers 1and 2. Some uptake of stain may
occur along either side of ventral nerve cord (Fig. IK).
Habitat and Distribution.-Eastern Pacific Ocean, off southern California, Santa
Barbara to San Diego, 10 to 122 m depth, silty-sand sediments.
Remarks.-Staining patterns of glandular tissue have been increasingly included
in descriptions of maldanids (Green, 1991; Mackie and Gobin, 1993). However,
published information is lacking on most species and, as yet, the full potential of
this taxonomic character is unknown. Members of the Southern California Asso-
ciation of Marine Invertebrate Taxonomists (SCAMIT) routinely use methyl green
staining to discriminate maldanids, including anterior fragments. Members report
the staining pattern of Petaloclymene pacifica to be conservative and useful for
identifying anterior fragments with at least 9 setigers (L. Lovell and T. Phillips,
pers. comm.).
ACKNOWLEDGMENTS
Special thanks to R. Velarde (City of San Diego Treatment Plant) for first bringing to my attention
the new species. He is also thanked for the use of the compound microscope and drawing tube at the
City of San Diego biological laboratory. L. Lovell (consultant) and T. Phillips (City of Los Angeles
Hyperion Treatment Plant) reintroduced me to the new species and kindly provided adequate malerial
GREEN:PETALOCLYMENE PACWICA. ANEWMALDANIDAE(POLYCHAETA) 239
for the species description, including the holotype and paratype specimens; they also provided infor-
mation on the conservative character of the methyl green staining pattern as an aid to identifying
anterior fragments. L. Harris (LACM-AHF) is thanked for her assistance with the museum's collcc-
tion. The manuscript benefited from comments by Dr. K. Fitzhugh, L. Harris, and two anonymous
reviewers.
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DATEACCEPTED: June 26, 1996.
ADDRESS: MEC Analytical Systems, Inc., 2433 Impala Drive. Carlshad, California 92008.