Table Of ContentBeaufortia
INSTITUTE FOR SYSTEMATICSAND POPULATIONBIOLOGY
(ZOOLOGICAL MUSEUM) UNIVERSITYOFAMSTERDAM
Vol. 48, no. 7 November 14, 1998
Sphaeromatidae(Crustacea, Isopoda) of theBeagleChanneland
descriptionof Cymodopsisbeagelin. sp.
AngelinaBrandt
Zoological InstituteandZoological Museum,Marlin-Luther-King-Plalz 3,D-20146Hamburg
Keywords:Crustacea, Isopoda,taxonomy, Beagle Channel,South America,Southern Ocean,Subantarctic
Abstract
Duringanexpedition withRV VictorHensen (1994)and the RV Polarstern(1996)Isopoda Sphaeromatidae werecollected in
andofftheeastern entranceoftheBeagleChannel. Thespecies found, Caecocassidias patagonicaKussakin, 1967,Cassidinopsis
emarginata(Guérin-Méneville, 1843)and Moruloidea darwinii(Cunningham, 1871), werepreviously allpoorly orinsufficiently
described;therefore aredescription ispresented herein. Exosphaeromagigas(Leach, 1818)wasalso collected frequently,butit
wasalready redescribed earlier and thus only thelocalitiesarepresented. Moreover, anewspecies, Cymodopsisbeageli,n.sp.,
whichis mostcloselyalliedtoCymodopsis sphyracephalata Hurley& Janssen,1977,isdescribed fromtheBeagleChannel.
INTRODUCTION tions. Dorsal and lateral view of these species
have never been presented untilnow, nor com-
Specimens of the poorly known sphaeromatid plete illustrationsofallappendages. Exosphaeroma
isopods - Caecocassidias patagonica Kussakin gigas (Leach, 1818), however, was redescribed by
(1967), Cassidinopsis emarginata (Guérin-Méne- Brandt & Wâgele (1989) and is thereforenot
ville, 1843), and Moruloidea darwinii (Cunning- illustrated in thepresentpaper, but the localities
ham, 1871) - were discovered in collections of of the records of this circum-polar species from
isopods from the Beagle Channelandeast ofthe the southern hemisphere are presented. Caeco-
southern part ofTierra del Fuego (off the east- cassidias patagonica has only been treated by
ern entrance ofthe Beagle Channel). Theexist- Kussakin (1967). The genus Caecocassidias is
ing descriptions of these threeabove mentioned monotypical; Kussakin (1967) found the species
species are only brief, with incomplete illustra- in the Atlantic Ocean, off Argentina, north of
137
Fig. 1. Cymodopsis beageli n. sp., holotype male of 11 mm lengthin dorsal and lateralview andfrontoventral view ofhead;
antennula,leftmandible,maxillula and hypopharynx.
138
the Falkland Islands in 400-680m depth. Since The following abbreviations are used in the
thenit has neverbeen mentionedagain in the lit- text and figures: Al = antennula, A2 — antenna,
erature. However, the collectionof this beautiful BMNH = National History Museum, London,
and characteristic species east off the Beagle Hy = hypopharynx (= paragnaths), lMd = left
Channel now allows a complete and detailed mandible, Mxl = maxillula, Mx2 = maxilla,
redescription. Mxp = maxillipede, PI-7 = pereiopod 1-7, Pip
The species Cassidinopsis emarginata is known 1-5 = pleopod 1-5, rMd = right mandible, Urp
from the Subantarctic. This genus is also mono- = uropod, ZMH = Zoological Museum of
typic. It was found on algae and is distributed Hamburg, ZMSP = Zoological Museum St.
circumantarctically, on Tierra del Fuego, the Petersburg.
Falkland Islands, South Georgia, the Crozet
Islands, Kerguelen Island, and on Macquarie
Island. Its depth record ranges from 0-32 m SYSTEMATICS
(Harrison & Ellis, 1991). Moruloidea darwinii, has
frequently beenreported and sampled inArgen- Cymodopsis beageli n. sp.
tina, the Magellan region and on Tierra del Figs. 1-4
Fuego, South America, but is also known from
South andWest Australia,Kerguelen Island, and Type materialHolotype male of 11 mm
the Falkland Islands in the intertidal and sublit- length, ZMH K-38299.
toral from 0 m down towards 500 m depth
(Harrison & Ellis, 1991). However, the descrip- Type locality.- ANT XIII/4, st. 40/115,
tions ofboth species, Cassidinopsis emarginata and southernSouth America, Tierra delFuego, off
Moruloidea darwinii, were very incomplete, the the eastern entrance of the Beagle Channel
habitus was only outlined and only very few (compare Figure 15).
appendages were illustrated; complete descrip-
tionsofthesespecies are still lacking. Description ofholotype male
A key to the genera of the Sphaeromatidae Length ofmale, 11 mm;headwithone dorsome-
including distribution lists of the species was dial elevation and two frontolateral protrusions
already published by Harrison &Ellis (1991). For in frontofthe eyes (Fig. 1).Eyes large, ofyellow-
distribution of the species presented compare brownish color in fixed condition, slightly quad-
Fig. 15. rangular, consisting ofmanyocellae. Pereionite 1
longest and almost as broad as fourth one, not
fused with céphalothorax and equipped with 2
MATERIALAND METHODS dorsal and 2 lateralblunt spines. Pereionites 2-4
smallest and shortest, equal in size and length,
The species of the Sphaeromatidae presented, pereionite 5 broadest and slightly longer than2-
were collected in November 1994 during the 4 and 6-7. All pereionites smooth, with a hori-
"Joint Chilean-German-ItalianMagellan Victor zontal shallow ridge dorsally ofpereionites 3-5 as
HensenCampaign", acruise withRV VictorHensen illustrated in lateral viewon Fig. 1. All pleonites
by means of an epibenthic sledge (Brandt & fused with pleotelson, but pleonite 1 indicatedby
Barthel, 1995) in and off the Beagle Channel, deep suture. Pleotelson narrowing andacuminat-
and during an expedition with RV Polarstern in ing caudally, with elongated caudal apex,pleotel-
1996 (ANT XIII/4) off the eastern entrance of son broadest anteriorly, equipped with 3 strong
the Beagle Channel, with the same epibenthic dorsal blunt spines, one anteriorly, one medially
sledge. On the vessels, the animals were fixed in and one caudally (see dorsal and laterial view
formalin (4%), and later transferred into ethanol with arrows in Figure 1).Uropods inserted ante-
(70%). The drawings were prepared with the riolaterally.
help of a camera lucida. The specimens are A1 (Fig. 1) with 3 peduncular and 18flagellar
deposited in the Zoological Museum ofHam- articles. First peduncular article longest, with a
burg. mediolateral feather-like seta andfewmedial and
139
Fig. 2. Cymodopsis beagelin.sp., holotype male,antenna, rightmandible, maxilla, maxillipede, andpereiopods 1-3
140
distal simple setae. Second article one fourth of one shortest and broadest, equipped medially
first in length, with 2 feather-like and 3 very with some long simple setules, and 13 setulated
small distally branchedsetae, thirdarticle as long apical setae ofvarying lengths. Medial endite
as first, without setae. First flagellar article small, with 4 setulated setae, longer and stronger than
ring-like, with 3 simple and 4 feather-like setae, those on innerendite. Outer endite with 9 setae,
second flagellar article three times as long as which bearalateralrow ofsmall spinules.
first,without setation, thirdand following flagel- Mxp (Fig. 2) without epipod, strong endite
lararticles narrowing distally, with 2 aesthetascs and a five segmented palp. Enditeon distal mar-
and 2 long and 2 short simple setae, last article gin with 2 distodorsal rows of laterally serrated
also bearing asingle feather-like seta. setae. One coupling hook medially on endite.
A2 (Fig. 2) with 5 peduncular and 18 flagellar First article ofpalp shortest and quadrangular in
articles. First peduncular article short, ring-like, shape. Second article longest and broadest, dis-
without setation. Second article about three tally with distolateral protrusion, aboutas long as
times as long as first, almost of quadrangular basis ofnext following article of palp. Second,
shape, with 3 simple distal setae. Third article third and fouth articles all distomedially
shorter than second, with 2 distal simple setae. extremely produced, with a dense medial brush
Fourtharticle aboutas long as the first threearti- of long simple setae. Last article almost three
cles together, with 3 feather-like setae and some times as long as first article andvery slender, also
very small hair-like structures, some distally with long simple setae.
branched.Fifth article about as long as fourth, PI (Fig.2) shortest and strongest pereiopod.
with4 distaland 2 distomedialfeather-like and 2 Basis longest article, with aproximal feather-like
distomedial simple setae and some short setules. seta and some shallow distodorsal teeth-like
First flagellar article longest, with 2 simple apical structures. Ischium shorter than basis, mediodis-
setae, second flagellar article also with 2 simple tally slightly widening, with mediodistal strong
setae, following articles narrowing and shorten- simple spine-like seta and 2 simple ventral short
ing, with groupsof 4-8apical simple setae and 1 setae. Merus almost halfas long as ischium, with
shorter simple seta on the opposite side. 1 distodorsal simple short spine-like seta, and 4
Mandibles (Figs. 1 and 2) asymmetrical, palp simple distoventral setae, as well as some small
consisting ofthree articles. Pars incisiva ofright setules. Carpus slightly shorter than merus, of
mandiblenarrower than of left with one strong, quadrangular shape, with 4ventralstrong spine-
blunt tooth with two notches, on left mandible like setae ofvarying lengths. Propodus proximal-
with three notches. Laciniamobilis with 1 strong ly broader than distally, proximally with
tooth, bearing threenotches distally, spine row of medioventral protrusion, equipped with 3 strong
8-9 laterally serrated setae. Pars molaris stout, spine-like setae, in concave medioventral notch
with some long laterally serrated mediolateral some small teeth-like structures. Distodorsally of
setae, broad grinding surface andindentedlower propodus 1 feather-like seta and 3 simple setae of
margin. First article of palp about as long as varying lengths. Dactylus aboutas long as propo-
third, without setation. Second article of palp dus,with 1 longer and 1 shorterdistal clawanda
longest, second and third articles of both seta inbetween, ventrally with a row of small
mandibles with lateral rows ofsetae, on distal teeth.
two thirds ofarticles. P2-7 (Figs. 2 and 3) similar in shape andseta-
Hy (Fig. 1) consisting of2 smaller inner lobes tion to pereiopod 1, but longer and less stout.
and 2 larger outer lobes, both lobes with short Basis ofP2-4 distally broader thanproximally,
simple apical setae. without setation, of P 5-7 not produced distally,
Mxl (Fig. 1) of2 endites, both slightly nar- with some distal setules and 2 feather-like setae
rowing distally, lateral one with 11 strong spines each. Ischium of P2-5 also equipped with 1
of different shapes, some equipped with addi- distodorsal simple short spine-like seta, on P6
tional subsetules. Medial endite shorter, with 4 and P7 merus elongated, almost as long as basis,
strong, curved subsetulate spines. lacking this strong seta. Merus of P2-P7 shorter
Mx2 (Fig. 2) consisting of three endites, inner than ischium, ventralside covered withsetules of
141
Fig. 3. Cymodopsis beagelin. sp.,holotype male,pereiopods 4-7, andpleopods 1-3.
142
Fig. 4.Cymodopsisbeagelin.sp.,holotypemale,pleopods4 and 5, uropod.
differentdensity, most densely coveredon P3 and Plp3 (Fig. 3) ofmalewith short, almost quad-
P3. Ventrally anddistodorsally with some simple rangular sympod, bearing threelong medial cou-
long setae. Carpus slightly longer than merus, pling setae as well. Endopod with distal and dis-
ventrally also with setules andsome simple setae, tolateral row of long plumose setae. Exopod
distodorsally with a feather-like seta. Propodus long-oval, withdistinct suture line inapical third
only slightly longer than carpus, similar in seta- oframus, bearing distolateral and distal long
tion to carpus, except a complete ventral row of plumose setae.
long simple setae and an accompanying simple Pip 4 and 5 (Fig. 4) both about subequal in
seta besides the feather-like distodorsal seta. size, with thin endo-and exopod, endopod ofPip
Dactylus as in P1. 4 with 4 apical plumose setae, exopod also with
Plpl (Fig. 3) ofmale with short, round oval suture line in apical part ofthe ramus, but only
sympod, bearing three long medial coupling with 1 single plumose distalseta; pip 5 endopod
setae. Endopod of male almost of triangular with 4 plumose and 1 simple setae, exopod with
shape, with medial row ofsetules and distaland 3 distomedial lobes, equipped with small teeth-
distolateral row of long plumose setae. Exopod like structures.
with distolateraland distal long plumose setae. Urp (Fig. 4) with fused sympod, endo-, and
Plp2 (Fig. 3) of male also with short sympod, exopods, bearing some proximal, some lateral
butalmost of quadrangular shape, also equipped and some distal setules, distolaterally 4 simple
with 3 medial coupling hooks. Endopod slightly setae.
longer than exopod, almost triangular, with
broad, distally acuminating appendix masculina, REMARKS
inserting proximolaterally and exceeding the Cymodopsis beageli n.sp., is most closely allied to
endopod aboutonefourthofits length. Endopod Cymodopsis sphyracephalata Hurley &Janssen, 1977,
also distally and distolaterally with row of long which was found in New Zealand(NZ 01
plumose setae. Exopod long oval, with distal and Holotype H-147; stn. F147) This new species
distolateralrow oflong plumose setae. was also compared with materialfrom Cymodopsis
143
sphyracephalata Hurley &Janssen, 1977 from the Caecocassidias patagonica Kussakin, 1967
National Museum of New Zealand BS 648; Figs. 5-8
42°29.2'S 176°06.3'E, northern Mernooslope,
1568m, 11.1.1979, R. V Tangaroa (NZOI stn. Caecocassidiaspatagonica Kussakin, 1967:237
R6), onmudand boulders, det. G. F. Hicks (CR Caecocassidiaspatagonica; Harrison, 1984:371
8290). However, the clypeus ofC. beageli is less
elongated distally than thatof C. sphyracephalata, Type material.- 2 paratype females of 12
the mediodorsalaspects ofthe pereionites of the and 13 mmlength, ZMSPN2/46721.
newspecies are less pronouned than in C. sphyra-
cephalata, and thepleotelson ofC. beageli is broad- Type locality.- Atlantic ocean 43°40'S 59°
er andmore robust andalso slightly shorter then 35'E, off Argentina, north of the Falkland
in C. sphyracephalata. Moreover, the mediodorsal Islands, in 400-500 m depth, coll. Koltun &
blunt spine on pleotelson of the latter is only a Pasternak, 16.6.1958, vessel „Ob".
shallowerprotrusion compared to thepronounc-
ed spine ofC. beageli. Like for C. sphyracephalata Material used for r ede s cription . -
the femaleofC. beageli is unknown. Male of 15,5 mm length, ANT XI1I/4, st.
40/109, southern South America, Tierra del
Exosphaeroma gigas (Leach, 1818) Fuego, off the eastern entrance of the Beagle
Channel, ZMHK- 38300(compare Fig. 15).
SphaeromagigasLeach 1818
Sphaeroma juvenii Kraus, 1843 Redescription of male
Sphaeroma propinqua Nicolet, 1849 Length of male, 15,5 mm; head straigth, very
Sphaeroma chilensis Dana, 1853 flat, laterally elongated and broaderthan follow-
Sphaeroma obtusaHutton, 1879(in Chilton, 1909) ing pereionites, with dorsal setules (Fig. 5). Eyes
not discernable, not any vestige ofeyes found.
Type material.- BMNH 1979:420:1, syn- Pereionite 1 slightly shorter than second, which
type, locality unknown; pres.: Sir Joseph Banks is the longest pereionite, not fused with
Collection (via the LinneanSociety ofLondon). céphalothorax. All pereionites of about equal
Material from the present collections: 10 juve- width. Pereionite2 slightly longer thanfollowing.
niles from station 1200 (14.11.1994, RV Victor All pereionites with shallow dorsomedialeleva-
Hensen), 55 °38.52'S-55°38.57'S, 67°12.86'W- tion and shortdorsomedialsetules.
67°12.26'W, 40 m depth, on crushed mollusc All pleonites fused with pleotelson, but pleo-
shells; 2 juveniles from station 1206(14.11.1994, nites 1 and 2 indicated by suture lines laterally.
RV Victor Hensen), 55°48.13'S-55°48.10'S, Pleotelson narrowing and acuminating caudally
66°58.45'W-66°58.62'W, 66 m depth, on fine, (see dorsal viewin Fig. 5), with elongated caudal
crushed mollusc shells; 121 juveniles on station apex, pleotelson broadest anteriorly, equipped
1213(15.11.1994, RV VictorHensen), 55°06.89'S- with 1 dorsomedial strong blunt spine (laterial
55°06.72'S, 66°39.95'W-66°39.92'W, 63 m viewinFig. 5).Uropods insertedanteriolaterally.
depth, on crushedmollusc shells. A1 (Fig. 6) with 3peduncular and 16flagellar
articles. First peduncular article longest, with
Distribution.- Circum-Antarctic: Peru, Ma- two lateral short setae. Secondarticle one fourth
gellan area, Tierra del Fuego, Chile, Falkland of first in length, with 5 feather-like setae and
Islands, Crozet Island, Kerguelen Island, South some small setules, third article about as long as
Africa, Macquarie Island, Tasmania, South second, but only a fourth in width ofsecond,
Australia, Campbell Island, Auckland Islands, with some lateral fine setules and 2 longer sim-
New Zealand, Chatham Rise, depth ranging ple setae. First flagellar article small, ring-like,
from 0-270 m (localities after Dana, 1953; with 4 feather-like setae, second flagellar article
Vanhôffen, 1914; Tattersall, 1914, Kussakin, fourtimes as long as first, without setation, third
1967) (compare Fig. 15). andfollowing flagellar articles narrowingdistally.
Fifth to fifteentharticles with 1 aesthetasc and 2
144
Fig. 5.Caecocassidias patagonicaKussakin, 1967,male of15.5mm lengthindorsaland lateral view and frontoventral view of
head,leftand rightmandibles and hypopharynx.
145
Fig. 6.CaecocassidiaspatagonicaKussakin, 1967,male antennula,antenna, maxillula, maxilla, maxillipede,andpereiopod 1.
146
