Two new deep-water species of the gutless genus Olavius (Oligochaeta: Tubificidae) from both sides of North America

4 Pages·1991·1.9 MB·English

PROC. BIOL. SOC. WASH.
104(3), 1991, pp. 627-630
TWO NEW DEEP-WATER SPECIES OF THE GUTLESS
GENUS OL^F7C/5(OLIGOCHAETA: TUBIFICIDAE)
FROM BOTH SIDES OF NORTH AMERICA
Christer Erseus
Abstract.—Olavius tannerensis, new species, from the continental shelf off
California, and O. rallus, new species, from offNorth Carolina, are described.
The former is the first member ofthe genus known from the Pacific coast of
NorthAmerica,thelatterthefirstgutlessoligochaetecollectedatbathyaldepths
(583 m). Both species have small atria and complex copulatory sacs, but they
lack penial setae. They are distinguished from each other by the location of
their spermathecal pores.
The gutless oligochaetes, over 50 de- Continental Shelf Project in the Southern
scribed species within Inanidrilus Erseus, California Bight, placed at the author's dis-
1979a and Olavius Erseus, 1984, are com- posal by the Allan Hancock Foundation,
mon in shallow marine waters of tropical UniversityofSouthCalifornia, LosAngeles
andsubtropicalareas. Theyareparticularly (courtesy. Dr. J. Kudenov; now at Univer-
well represented in the poorly oxygenated sity of Alaska, Anchorage). The specimen
carbonate sands ofcoral reefs (Giere et al. of O. rallus originates from the Study of
1984; Erseus 1984, 1990). Only three spe- Biological Resources on the U.S. South At-
cies (ofOlavius) have been found in deeper lantic Continental Slope and Rise (Blake et
(>100 m), colder waters. Olavius tenuissi- al. 1987),supportedbycontractnumber 14-
mus (Erseus, 1979b) and O. cornuatus Da- 12-0001-30064 from the U.S. Department
m
vis, 1984occurtoatleastabout 140 depth ofInterior, Minerals Management Service,
on Georges Bank, offMassachusetts in the to Battelle New England Marine Research
NorthwestAtlantic(Davis 1984, 1985),and Laboratory, Woods Hole Oceanographic
O. macer Erseus, 1984 was described from Institution, and Lamont-Doherty Geologi-
m
a single station at 170 in the eastern part cal Observatory (courtesy. Dr. Nancy Ma-
ofthe GulfofMexico (Erseus 1984). ciolek-Blake).
Inthepresentpaper,twoadditionaldeep- The worms were stained in paracarmine
waterspecies ofOlaviusare described. Ola- andmountedwholeinCanadabalsamprior
viustannerensis, newspecies,isthefirstgut- to examination. Types are deposited at the
less oligochaete recorded from the Pacific Los Angeles County Museum of Natural
coastofNorthAmerica, O. rallus, new spe- History (LACM), Los Angeles, California,
cies, the first one from bathyal depths; the and at the National Museum of Natural
m
latterwasfoundat583 offNorthCarolina History (USNM), Washington, D.C.
(Northwest Atlantic).
Olavius tannerensis, new species
Fig. lA, B
Material and Methods Holotype.-I.KCM AHF 1528, whole-
The materialofO. tannerensiswas found mounted specimen from Tanner Bank,
in a collection ofoligochaetes from the Bu- Southern California Bight, 173 m, coarse
reau of Land Management (BLM) Outer sandwithshell(BLMprojectSta.no. 81828).
628 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig. L A, B. Olavius tannerensis. A, Free-handdrawingofsetae; B, Lateral viewofspermathecaandmale
genitaliainsegmentsX-XI; C, D, Olaviusrallus. C, Free-handdrawingofseta;D, Lateralviewofspermatheca
andmalegenitaliainsegmentsX-XI.Abbreviations.—a,atrium;cs,copulatorysac;prl,anteriorprostategland;
pr2, posteriorprostategland; s, spermatheca; se, setae; vd, vasdeferens.
Paratype.—US'Nyi 136576, specimen segments. Penial setae absent. Male pores
from type locality. pairedinlinewithventral setae, posteriorly
Etymology.—'HQ.medi tannerensis for the in XI. Spermathecal pores paired, imme-
X
type locality, Tanner Bank. diately antero-ventral to dorsal setae in
Description. —YioXoXy^t not complete; (see Fib. IB).
mm
paratype 5.3 long, 46 segments. Width Alimentary canal absent. Male genitalia
at XI 0.15 mm. Prostomium and pygidium (Fig. 1B)paired. Vasdeferens 5-7 nvs\wide,
small, elongate with rounded tips. Body longerthan atrium;junction with latter not
round in cross-section. Clitellum extending observed. Atrium somewhat curved, pear-
over V2X-XII. Secondary annulation con- shaped, about 30-40 tim long, 21-25 fira.
spicuous, annuli 5-7 per (postclitellar) seg- wide, with very thin outerlining and thick,
ment. Setae (Fig. lA) bifid, wide subdental granulated inner epithelium, opening into
ligaments,andwithupperteethvariablylong inner part of large, folded copulatory sac.
but always thinner than lower teeth. Setae Two prostate glands present, but attach-
26-37ixm.long, 1-2,jumthick, (2)3perbun- ments with atrium not observed. Sperma-
dle anteriorly, 2 per bundle in postclitellar thecae (Fig. IB, s) with very short ducts.
VOLUME 104, NUMBER 3 629
and elongate, very thin-walled ampullae; notobserved.Atriumsmall,somewhatpear-
latter70-100ij,mlong, 20-27fxmmde,con- shaped, about 25 ixm long, about 20 nm
taining large random masses ofsperm. wide, with very thin outer lining and thick,
Remarks.—As indicated by the small granulated inner epithelium, opening into
atria, the well developed copulatory sacs, inner part ofsmall, folded copulatory sac.
and, in particular, the unusual location of Two prostate glands present, posterior one
thespermathecalporesnearthedorsalsetae attached to atrium by long stalk. Sperma-
in segmentX, Olaviustannerensisisclosely thecae (Fig. ID, s) with very short ducts,
related to the northwest Atlantic O. tenuis- and elongate, very thin-walled ampullae;
simus (redescribed by Erseus 1990) and O. latterabout 55 fxm long, about 20 ^m wide,
finitimus Erseus, 1990. However, the new but devoid ofsperm (specimen precopula-
species is readily distinguished from these tory).
taxa by its lack ofpenial setae. Remarks. The male genitalia ofO. rallus
See also Remarks for O. rallus below. arevirtuallyindistinguishablefromthoseof
Distribution and habitat.—Known only O. tannerensis described above, but the
from the type locality offsouthern Califor- spermathecal pores of the former are dis-
nia, NE Pacific. Subtidal coarse sand, 173 tinctlymoreanteriorthanthoseofthelatter.
m
depth. Olavius rallus is also very similar (e.g.,
withregardto the more anteriorposition of
thespermathecalpores)toO. vacuusErseus,
Olavius rallus, new species 1990, a largely Caribbean species that has
D
Fig. IC, been found as far north as in Chesapeake
Holotype. -VSNM 136577, whole- Bay,Virginia(Erseus 1990). Olaviusvacuus,
mounted specimen from the continental however, always bears a filiform process on
slope off Cape Lookout, North Carolina, its pygidium and generally has a large pa-
U.S.A., 34°16.2'N, 75°45.8'W, 583 m (No- pilla inside the wall ofeach copulatory sac.
vember 1983;courtesyN. Maciolek-Blake). Distribution and habitat.—Known only
Etymology. —Named rallus (Latin for from the type locality offNorth Carolina,
NW m
'thin') for its slendemess. Atlantic. Bathyal sediments, 583
Description.—Length 7.4 mm, 39 seg- depth.
ments. Width at XI 0.13 mm. Prostomium
and pygidium small, somewhat triangular.
Body round in cross-section. Clitellum ex- Acknowledgments
tending over y2X-Xll. Secondary annula- I am indebtedto Dr. J. Kudenovand Dr.
tion indistinct. Setae (Fig. IC) bifid, with Nancy Maciolek-Blake, for placing the oli-
subdental ligaments, and with upper teeth gochaete material at my disposal; to Ms.
thinnerandshghtlyshorterthanlowerteeth. Barbro Lofnertz and Mrs. Birgitta Vallan-
Setae about 30 ^m long, 1-1.5 ixm thick, 3 der, for technical assistance; and the Swed-
perbundle anteriorly, 2 perbundle in post- ish Natural Science Research Council, for
clitellarsegments. Penial setaeabsent. Male financial support.
pores paired in line with ventral setae, pos-
teriorlyinXL Spermathecalporespairedin
linewith dorsal setae, in anterior part ofX, Literature Cited
about mid-way between septum 9/10 and
dorsal setae ofX (See Fig. ID). Blake,J.A.,etal. 1987. Studyofbiologicalprocesses
Alimentary canal absent. Male genitalia o2.nRtehpeoUr.tS.noS.ouMtMhSAtl8a6n-t0i0c9s6l.opUe.Sa.ndDeripsae.rtPmheanste
(Fig. 1D)paired. Vasdeferens7-9 ixmwide, ofthe Interior, Minerals Management Service,
longerthan atrium; butjunction with latter Washington, D.C. 414 pp. + appendices.
630 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
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ta,Tubificidae)fromGeorgesBank(NWAtlan- Belize, and other parts ofthe Caribbean Sea,
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a marine tubificid (Oligochaeta) from Florida, kodermatusGiere,atubificidofstructural,eco-
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. 1979b. Taxonomic revision ofthe marine biologia 115:83-89.
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Department ofZoology, University ofG6-
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