Records of the marine genus Bathydrilus (Oligochaeta: Tubificidae) from California, with descriptions of two new species

5 Pages·1991·1.6 MB·English

PROC. BIOL. SOC. WASH.
104(3), 1991, pp. 622-626
RECORDS OF THE MARINE GENUS BATHYDRILUS
(OLIGOCHAETA: TUBIFICIDAE) FROM
CALIFORNIA, WITH DESCRIPTIONS OF
TWO NEW
SPECIES
Christer Erseus
Abstract—Bathydrilus litoreus Baker, 1983, B. parkeri, new species, and B.
rusticus, new species, are described from subtidal habitats in southern CaU-
&
fomia. Bathydrilusparkeri appears closely related to B. exilis Erseus Davis,
1989, a larger species from Hawaii, but its postclitellar setae are not single-
pointed as those ofthe latter taxon. Bathydrilus rusticus resembles B. torosus
Baker, 1983, an intertidal species from British Columbia, butis discriminated
by its much different spermathecae.
Baker(1983)describedtwointertidalspe- NaturalHistory(LACM), LosAngeles, Cal-
cies oiBathydrilus Cook, 1970, B. litoreus ifornia.
Baker, 1983 (from British Columbia and
Washington) and B. torosus Baker, 1983 Bathydrilus litoreus Baker, 1983
(fromBritishColumbia),whicharetheonly
members of this genus recorded from the BathydriluslitoreusBaker, 1983:2162-2164,
Pacific coast ofNorth America to date. In figs. 1, 2A.-Erseus 1990:68-69, fig. 13.
the present paper, three species of Bathy- Newmaterial.-USNM 136578-136580,
drilus from offshore localities in southern 3specimensfromSouthernCaliforniaBight:
Californiaaretreated. OneisB. litoreus, the 1 from Santa Cruz Island (slope of Santa
other two are new taxa. CmsBasin), 260 m, mediumtocoarse sand
The material originates from (1) the Bu- (BLM project Sta. no. 80907); 1 from same
reau of Land Management (BLM) Outer areaandsediment,but271 m(BLMproject
Continental Shelf Project in the Southern Sta. no. 80908); 1 from same area, but 257
California Bight, placedat the author's dis- m, medium sand with small pebbles (BLM
posal by the Allan Hancock Foundation, project Sta. no. 80929). LACM, 3 speci-
UniversityofSouthCalifornia, LosAngeles mensfromSouthernCahfomiaBight: 1 from
(courtesy, Dr. J. Kudenov; now at Univer- TannerBank, 96 m, finesand(BLMproject
sity ofAlaska, Anchorage); and (2) the Los Sta. no. 81505); 1 from same area, but 203
AngelesCountySanitationDistrictsbenthic m, coarse sandwith shell(BLMproject Sta.
sampling offLos Angeles (courtesy. Dr. T. no. 81827);and 1 fromSanNicholasIsland,
Parker,JointWaterPollutionControlPlant, 279 m, coarse sand with small rocks (BLM
L.A. County Sanitation Districts). The project Sta. no. 84103).
worms were stained in paracarmine and Remarks.—Originallydescribedfromin-
mounted whole in Canada balsam prior to tertidal localities in British Columbia and
examination. Types and other material are Washington (Baker 1983), this species was
deposited at the National Museum ofNat- recently reported also from subtidal depths
ural History (USNM), Washington, D.C., (15 m) in Southwestern Australia (Erseus
and the Los Angeles County Museum of 1990). The new specimens from Southern
VOLUME NUMBER
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lOjjm
Fig. 1. Bathydrilusparked.A,Anteriorsomaticseta;B,Postclitellarsomaticseta;C,Penialsetae;D,Lateral
view ofgenitalia in segments X-XI. Abbreviations: a, atrium; pp, pseudopenis; prl, anterior prostate gland;
pr2, posteriorprostategland; ps, penial seta; s, spermatheca.
California are from deeper sites, at 96-279 the Australian material there is also some
mdepth. Abriefdescriptionofthenewma- variation in this character, the penial setae
terial follows: mostly 3 (occasionally 2 or 4) per bundle
Length ofonly complete individual 14.0 (Erseus 1990). The penial setae ofthe new
mm, about 77 segments; other, incomplete, material are invariably 3 per bundle.
wormslonger, butmuchstretched. Somatic Distributionandhabitat.—CaMomia(new
setae 3 per bundle anteriorly, 2 per bundle record), Washington, BritishColumbia; also
in postclitellar segments. Penial setae sin- southwestern Australia. Intertidal and sub-
m
gle-pointed, straight and closely parallel tidal sands, to at least 279 depth.
withinbundle, 100-140/nmlong, 3 perbun-
Bathydrilusparkeri, new species
dle, and enclosed in large, glandular, bi-
lobed sac (see Erseus 1990: fig. 13C). Atria Fig. 1
115-150 ^m long, 45-50 ^m wide. Holotype.-\]Sl<iM 136573, whole-
With regard to body size, the newworms mounted specimen.
—
thusresembletheoriginalB.C./Washington Typelocality. OfTKouradiotowers, Pa-
material more than they do the Australian los Verdes Peninsula, Los Angeles, Califor-
mm
specimens; the latter were 16.5-22.1 nia, 30m,siltysand(July 1980;LosAngeles
long with 90-115 segments. The Califor- County Sanitation Districts benthic sam-
nian individuals, however, have somewhat pling station no. 6D).
smaller penial setae and atria than the pre- Paratypes.—U^'NM 136574, 1 specimen
viouslystudiedmaterial;inthelatter,penial from type locality. LACM AHF 1533, 1
setae were 140-160 txva, atria 170-230 /nm specimen from type locality.
long. Etymology. —^am&d for Dr. Thomas
In the more northern populations of B. Parker(JointWaterPollutionControl Plant,
litoreus, the penial setae are mostly 2 (oc- Carson, California), who kindly provided
casionally 3-5) perbundle (Baker 1983). In the material.
624 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Description. —Length 10.1-10.9 mm, slender, more or less erect atria and some-
from about 70 to 78 segments. Widthat XI what curved penial setae (Erseus & Davis
0.27-0.35 mm. Prostomium elongate. Epi- 1989). The posterior setae of Bathydrilus
dermal glands as large dorsal patches in exilis, however, are not bifid as those ofB.
many segments, well visible in at least one parkeri but sharply single-pointed. More-
specimen. Clitellum extending over ViX- over, the Hawaiian species is about twice
XII. Somatic setae 40-50 fxm long, 2-3 jum as large (up to at least 26.5 mm, with 149
thick, 3 perbundle anteriorly, 2 perbundle segments) as the new taxon.
in postclitellar segments. These setae bifid, Distribution and habitat.—Known only
with upper tooth shorter and thinner than from type locality near Los Angeles, south-
lower,morepronouncedlysoinpostclitellar em California. Subtidal silty sand, 30 m
(Fig. IB)thaninanteriorsegments(Fig. lA). depth.
Penial setae (Figs. IC; D, ps) 2 per bundle,
75-90 ixm long, 5-7 /xm thick, single-point- Bathydrilus rusticus, new species
ed with somewhat curved tips; within bun- Fig. 2
dle,innerendsofsetaewiderapartthantips. Holotype.-LACM AHF 1527, whole-
Maleporespaired,inlinewithventralsetae, mounted specimen from type locality.
posteriorlyinXL Spermathecalporespaired Type locality.-Tanner Bank, Southern
in lateral lines, in most anterior part ofX. California Bight, 113 m, coarse sand and
Pharyngeal glands in IV-VIII(IX), well shells (BLM project Sta. no. 81810).
developed. Some anterior septa, in partic- Paratype.—US'NM 136575, specimen
ular 6/7 and 7/8, thickened, conspicuously from type locality.
muscular. Male genitalia (Fig. ID) paired. Etymology.—Named rusticus (Latin for
Vasdeferens not seen inavailable material, 'simple,plain'),alludingtothisspecies'lack
butappearstoenterectalendofatriumnear ofpenial setae.
mm
attachment ofanteriorprostategland. Atri- Description.-Hoioiype 11.8 long,
um slender and spindle-shaped; erect or with67 segments; paratype9.9 mm, 44 seg-
somewhattilted overto posterior, 150-220 ments. Width atXI 0.23-0.25 mm. Prosto-
ixm. long, 40-47 /um wide, with 2-3.5 /um mium large, somewhat elongate with
thick outer lining ofmuscles, and ciliated, rounded tip. Epidermal glands not ob-
granulatedinnerepithelium. Anteriorpros- served. Clitellum extending over V2X-XII
tate gland attached to ectal end ofanterior in holotype, poorly developed in paratype.
face ofatrium, posterior prostate gland to Somatic setae 55-75 ixm long, 2.5-3.5 nm
apex ofatrium. Atrium terminating in bul- thick, 2-3 per bundle anteriorly, 2(3) per
bous, simple, pseudopenis, but details not bundle in postclitellar segments. Anterior
clear in available material. Spermathecae setae(Fig. 2A)bifid,withuppertoothmuch
(Fig. ID, s) with very short ducts, and oval shorterandthinnerthanlower. Postclitellar
ampullae,70-125ixmlong,45-106fxmwide. setae with rudimentary upper tooth, or
Lumenofspermathecaewithsomeglobules (more commonly?) single-pointed with
ofsecretion and an amorphous substance, curved tip (Fig. 2B). Ventral setae of XI
butnospermobserved(specimensprecopu- (penial setae) absent. Male pores paired, in
XL
latory?). line with ventral setae, posteriorly in
Remarks.—Bathydrilus parkeri appears Spermathecal pores paired, immediately
closely related to B. exilis Erseus & Davis, ventraltolaterallines,inmostanteriorpart
1989. Thelatter, which isknown onlyfrom ofX.
Hawaii, also has somewhat curved penial Pharyngeal glands extending in VIII, but
setaewithinnerendswiderapartthanouter poorly developed. Some anterior septa
tips, heavily muscular anterior septa, and somewhatthickened,butnotconspicuously
.
VOLUME NUMBER
104, 3 625
lOjjm
Fig. 2. Bathydrilusrusticus. A, Anteriorseta; B, Postclitellarseta; C, Lateralviewofspermathecaandmale
genitaliain segments X-XI (one side ofholotype); D, Outerend ofmale duct(otherside ofholotype). Abbre-
viations: vd, vasdeferens; otherabbreviationsasin Fig. 1
muscular. Malegenitalia(Fig. 2C, D)paired, upper teeth, muscular, posteriorly directed
partly extending into XII in paratype. Vas atria, and elongate (although morphologi-
deferens inconspicuous, 3-8 ixm wide, cally different) spermathecae, but they lack
somewhat coiled, and appars to enter ectal penialsetae. AccordingtoBaker(1983), the
end ofatrium near attachment ofanterior atria ofB. torosus open to the exterior on
prostate gland. Atrium slender, tilted over theventralaspectoflargepapillae; itispos-
to posterior, 150-230 fim long, 47-50 ixm sible that these papillae are everted pseu-
wide, with 2.5-5 ixm thick outer lining of dopenes ofa kind similar to those present
muscles, and ciliated, histologically bipar- in B. rusticus (see Fig. 2D),
tite inner epithelium; ental (longer) part of It is not clear from Baker's (1983) de-
atrium evenly granulated; granules ofectal scriptionwhetherthethick-walledectalpart
(shorter) part aggregated in discrete 'pack- ofthe spermathecae ofB. torosus is an un-
ages'. Anterior prostate gland attached to usually long spermathecal duct, or whether
ectal end ofanterior face ofatrium, poste- it is merely a part ofthe ampulla, but his
rior prostate gland to apex ofatrium. Atri- fig. 3C seems to suggest the former alter-
um terminating into hollow pseudopenial native. Be it any way, in B. rusticus, the
sac (best observed at one side ofholotype; spermathecal ducts are very short and nar-
Fig. 2D), but details not clear in available row, and clearly set off from the elongate
material. Spermathecae (Fig. 2C, s) with ampullae, and the sperm are arranged in
distinctducts, 30—45 nmlong, about 20 fim slender bundles inside an amorphous mass
wide, and elongate ampullae, 200-260 ixm in the spermathecae, not in roundish sper-
long, 40-75 ixm wide. Walls (and parts of matozeugmata (termed "spermatophores"
lumina?) of spermathecal ampullae with by Baker) as in B. torosus.
large globules of secretion; each ampulla Distribution and habitat.—Kno-wn only
containing an amorphous substance in from type locality in the Southern Califor-
which bundled sperm appear to be ce- niaBight(NEPacific). Subtidalcoarsesand,
mented. 113m depth.
Remarks.—Bathydrilus rusticus appears
Acknowledgments
closelyrelatedtoB. torosusBaker, 1983, an
intertidal species from British Columbia. I am indebtedto Dr. J. Kudenovand Dr.
Both taxa have setae with much reduced T. Parker, for placing the oligochaete ma-
626 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
terialatmydisposal;toMs.BarbroLofnertz dae(Oligochaeta)ofSouthwesternAustraUa.Pp.
and Mrs. Birgitta Vallander, for technical 43-88inF.E.Wells,D.I.Walker,H.Kirkman,
assistance;andtheSwedishNaturalScience &R.Lethbridge,eds..ProceedingsoftheThird
InternationalMarineBiologicalWorkshop: the
Research Council, for financial support. marinefloraandfaimaofAlbany,WesternAus-
tralia.Volume 1. WesternAustralianMuseum,
Literature Cited Perth, 437 pp.
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2167. Zoo-tax, Swedish Museum of Natural
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