Table Of ContentPROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
114(2):427-434. 200L
Antarctodius rauscherti, a new species (Crustacea: Amphipoda:
Ochlesidae) from the Antarctic Ocean
Charles Oliver Coleman and Judith Kauffeldt
Museum fiir Naturkunde, Institut fiir Systematische Zoologie, InvalidenstraBe 43,
D-10115 Berlin, F.R.G.
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Abstract. The Antarctic amphipod crustaceanAntarctodius rauscherti, new
species, is described. This species can be distinguished from its hypothetical
sister taxon, Antarctodius antarcticus, by its elongate peduncles ofthe antenna
1 and 2, pointed apical processes on peduncle articles 1 and 2 of antenna 1,
the shortened and strongly flexed rostrum and the truncate apices of coxa 2
and 3, and the lack of a dorsal hump on pleonite 3.
During cruise 48 (ANT XV/3) of RA^ Antarctodius Berge et al., 1999
Polarstem to the Weddell Sea in 1998, large Antarctodius rauscherti, new species
numbers of crustaceans were collected by Figs. 1-5
Dr. Martin Rauschert. In one of these sam-
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ples was an interesting amphipod that had Material examined.- Holotype oviger-
not appeared in previous benthic collections ous female, 5.7 mm; 2 paratypes, sex un-
from this region. It proved to be new to known, 3.9 and 4.7 mm; ZMB 27 309,
science and is described in detail herein. It Prap. No. 4607. —
was placedin the genusAntarctodius, erect- Type locality. Polarstern station 48/
ed only recently by Berge et al. (1999). 115, 73°37.0'S 22°24.9'W, 6 Feb 1998,
mm
They provided a cladistic analysis of the depth 756 m, dredge, 1 mesh size, do-
Ochlesidae Stebbing, 1910 and Odiidae Co- nor M. Rauschert. —
leman & Barnard, 1991a. They concluded Description of holotype. Cuticle rela-
the Odiidae was paraphyletic and placed tively soft, pitted. Head slightly telescoped
this family within the Ochlesidae. In addi- into pereonite 1; eyes apparently not pre-
tion, they considered the genus Antarcto- sent or if so pigments washed out in alco-
dius to be plesiomorphic within the family. hol; rostrum strongly flexed and shortened,
not surpassing halflength ofpeduncular ar-
Materials and Methods ticle 1 of antenna 1.
Pereonite 1 and 3 subequal in length
The animals were fixed in 70% ethanol, (Fig. la); pereonite 2 shortest and pereoni-
transferred into glycerol for the study and tes 6 and 7 longest; pleonites subequal in
drawn with acameralucidaon aLeicaWild length to pereonite 7. Pereon and pleon
MS dissecting microscope. The holotype with keel, on pleon segment 3 shallow keel
was dissected. Appendages and mouthparts only anteriorly, posterior dorsal surface
were transferred onto slides and mounted in rounded. Epimera 1-3 posteroventral cor-
Euparal (Roth). Details were drawn under ner pointed, posterolateral mairgin lobate
a Leica DMLB light microscope using a and rounded on pleonites 1 and 2, pointed
camera lucida. on 3 (Fig. la). Posterodorsal hump on
The type material of the new species is pleonite 3 absent. Urosomite 1 smooth, sub-
deposited in the Museum fiir Naturkunde in equal in length to urosomites 2 and 3 com-
Berlin. bined; urosomite 2 shortest, dorsally round-
428 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 1. Antarctodius rauscherti, new species, holotype ovigerous female, 5.7 mm. A, habitus, left side; b,
lower lip, slightly damaged; c, maxilla 1; d, maxilla 2, plates twisted; e, apex oflower lip (hypopharynx).
VOLUME NUMBER
114, 2 429
Fig. 2. Antarctodius rauscherti, new species, holotype ovigerous female, 5.7 mm. A, antenna 1; b, antenna
2; c, inner and outerplate ofmaxilliped; d, upperlip (labrum); e, maxillipeds, posterioraspect, right sideplates
and palp omitted; f, left mandible; g, right lacinia mobilis.
430 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
200^m
Fig. 3. Antarctodius rauscherti, new species, holotype ovigerous female, 5.7 mm. A, pereopod (gnathopod)
1, detail shows chela; b, pereopod (gnathopod) 2, detail shows chela; c, basis, ischium and merus ofpereopod
3; d, coxa ofpereopod 3; e, oostegite ofpereopod 3.
VOLUME NUMBER
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431
Fig. 4. Antarctodius rauscherti. new species, holotype ovigerous female, 5.7 mm, appendages, carpus pro-
podus and dactylus missing, a, pereopod 4; b, pereopod 5; c, pereopod 7; d, pereopod 6.
432 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 5. Antarctodius rauscherti, new species, holotype ovigerous female, 5.7 mm. a, pleopod 1, setaepartly
omitted; b, uropod 2; c, uropod 3; d, uropod 1, apices oframi damaged; e, coupling hooks ofpleopod; f, telson.
ed; urosomite 3 with laterodorsal ridge-like slender with pointed apex; incisor with
elevations. denticles; lacinia mobilis on left side slen-
Antenna 1 (Fig. la, 2a): peduncle article der, spine-like, strongly developed and
1 slightly surpassing ventral margin of dentate on right side (Fig. 2g); spine row
head, subequal to 2 and 3 combined, pos- present; pars molaris produced; palp 3-ar-
teroventromedial angle acutely produced, ticulate, inserted at molar level, article 3
article 3 with inconspicuous indication of with row of short setae and slightly longer
point, flagellum 9-articulate, each equipped apical setae.
with long aesthetascs. Lower lip (hypopharynx) (Fig. lb, e):
Antenna 2 (Fig. 2b): peduncle articles 1- lobes narrow, oblique apically and with
3 about the length ofarticle 4, article 5 sub- shallow depression apicomedially and
equal in length to article 4; flagellum 8-ar- deep excavations medially; mandibular
ticulate. processes narrow, long and rounded.
Upper lip (labrum) (Fig. 2d) longer than Maxilla 1 (Fig. Ic): outer plate elon-
wide, strongly tapering distally and clearly gate, pointed, with oblique margin bear-
notched apically, apex ofright side slightly ing stout serrate, spine-like setae on me-
shortened. dial margin; palp 2-articulate. reaching to
Mandible (Fig. 2f): mandibular body distal end of outer plate; inner plate short.
VOLUME 114, NUMBER 2 433
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Table 1. Comparison ofAntarctodius antarcticus andAntarctodius rauscherti, new species.
A. rauscherti.
Characters Af.emaantlaerc5timcums, newfesmpaecliees5,.7homlomtype
Cuticle Strongly sclerotized, not transparent soft and transparent
Rostrum surpassing ventral margin ofhead, strongly shortened and flexed
rather straight and stout
Peduncle ofantenna 1 bulky, article 3 not surpassing apex of elongate, article 2 surpassing apex of
coxa 1; stout with straight apical coxa 1; pointed postero-distomedial
margins acute processes on articles 1-2
Peduncle article 4 of length 1.6 X breadth length 3 X breadth
antenna 2
Peduncle article 5 of length 1.5 X breadth length 3.5 X breadth
antenna 2
Apex ofcoxa 2 and 3 truncate with anterior and posterior truncate with anterior and poster angles
angles rounded angular
Coxa 5 strongly produced laterally not strongly produced laterally
Pleonite 3 with dorsal hump posteriorly smooth
Dorsal surface of with lateral ridge-like elevations smooth
urosomite 2
extending beyond insertion of palp on concave anteromarginally, truncate apical-
outer plate, with 3 apical setae. ly; basis weakly sinuous in shape; ischium
Maxilla 2 (Fig. Id): outer plate tapering shortest; merus angular posterodistally; car-
distally, about same length as inner plate, pus lobe less than half the length of pro-
but wider, with long setae on oblique me- podus; propodus weakly expanded distally,
dioapical margin; inner plate with rounded with serrate palm; dactylus stout withpoint-
apex and shorter setae apicomedially. ed process on inner margin (detail of Fig.
Maxilliped (Fig. 2c, e): basis and outer 3b).
plate about subequal in length; inner plate Pereopod 3 (Fig. 3c, d, e): coxa excavate
narrow with distomedial angle produced; anteromarginally, with truncate angular
outer plate relatively wide, rounded apical- apex, subequal to that of pereopod 2; basis
ly, longer than distal margin of article 2 of strongly expanded posteromarginally; ischi-
palp; palp 4-articulate, somewhat longer um anteromarginally slightly excavate;
than outer plate; article 1 short; article 2 merus anterodistally acutely prolonged; car-
subrectangular with long setae on medial pus, propodus and dactylus missing.
margin; article 3 narrow, about half the Pereopod 4 (Fig. 4a): coxa straight an-
width of article 2 with long slender setae teromarginally, slightly angularly produced
medioapically. anterodistally, ventral margin truncate, pos-
Pereopod (gnathopod) 1 (Fig. 3a): coxa teroventral angle rounded, posterior margin
shorter than that of pereopod 2, tapering drawn out into a long pointed process; is-
distally, anterior margin concave, posterior chium with anteromarginal excavation;
margin rather straight; basis expanded merus not much expanded, anterodistal an-
proximoposteriorly, with some long setae gle drawn out a little subacutely, carpus,
on posterior margin; ischium subequal in propodus and dactylus missing.
length to merus; carpus elongate; propodus Pereopod 5 (Fig. 4b): coxa not strongly
73% of carpus length; propodus process of produced laterally, wider than long, poste-
chela substituted by stout spine, dactylus riorly angular and subacute, anterior lobe
bulky, with spine apically (detail of Fig. rounded; basis both margins weakly con-
3a). vex, produced into rounded lobe posterov-
Pereopod (gnathopod) 2 (Fig. 3b): coxa entrally; ischium pointed anterodistally;
434 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
merus expanded distally with long acute ex- cies from the high Antarctic. Only one oth-
tension posterodistally; carpus to dactylus er southern cold water species ofthe family
missing. Ochlesidae, Curidea magellanica Coleman
Pereopod 6 (Fig. 4d): coxa longer than & Barnard, 1991b, is known from the Ma-
wide, anteriorly oblique with row of setae, gellanic region.
posteriorly rather rounded; basis longer In the original description of A. antarc-
than wide, both margins convex, postero- ticus the palp of maxilla 1 is described as
ventral margin lobe-like; ischium pointed 1-articulate. InA. rauscherti, new species it
anterodistally; merus expanded distally has the same length, but without doubt is
with long lobe-like acute extension postero- 2-articulate. The authors checked this char-
distally; carpus to dactylus missing. acter on A. antarcticus specimens from the
Pereopod 7 (Fig. 4c): coxa smallest;basis collection of the Museum fiir Naturkunde
wide, posterior margin clearly convex, pos- Berlin and found out that also this species
teroventral margin lobe-like; ischium short- has a 2-articulate maxillulary palp.
est, less than % of basis width; merus ex- Table 1 compares the two species of the
genus Antarctodius.
panded distally with long lobe-like acute
extension posterodistally; carpus, propodus
Acknowledgements
and dactylus missing.
nerPlreoapmouds 1s(lFiiggh.tl5ya):shaosrtienntehde;facmoiulpyl;iinng- MsThInegaeubtohrogrsKiwloiausldfosripnrcoevreildyinlgiktehteomthwaitnhk
hooks harpoon-like (Fig. 5e). literature.
Uropod 1 (Fig. 5d): rami subequal in Literature Cited
length, tips broken.
Uropod 2 (Fig. 5b): peduncle shorter Berge, J., W. Vader, & C. O. Coleman. 1999. A cla-
distic analysis of the amphipod families Och-
than inner ramus; outer ramus shorter than lesidae and Odiidae—, with description ofa new
inner, rami each with a terminal spine, both species and genus. Crustaceans and the bio-
margins spinose. diversity crisis. Proceedings ofthe fourthInter-
Uropod 3 (Fig. 5c): peduncle short; outer national Crustacean Congress, Amsterdam,
ramus shorter than inner, both rami spinose. ColemaBnr,illC,.pOp..,2&39-J.26L5..Barnard. 1991a. Revision of
Telson (Fig. 5f) elongate, longer than dis- Iphimediidae a—nd similarfamilies (Amphipoda:
tal margin of peduncle of uropod 3, taper- Gammaridea). Proceedings of the Biological
pianigErtsdyiomsfotlallologyny,g.—cslleeTfnthdee5r5sdp%oercsioaefls lfieasncidgatelhd,isceawttaieet.dh t2o pSs,phoeic&cpiieoetdsya,:offOrcoWhma.lse1Mhs9aii9dgn1aegbel.t)lo.aCn—nur1PiS0rtd4roi:acai2et5me3ad(-giC2ern6lug8sls.taanocifecaat:,heAnBmei-w-
our dear colleague Dr. Mcutin Rauschert, ological Society ofWashington 104:269-278.
who collected these animals. Watling, L., & H. Holman. 1981. Additionalacanthon-
—
Discussion. The new species is simila&r oAtmopzhoimaptoidda, pfarroammpthhiethoSiodu,thearnnd Ostceegaonc.e—phaPlriod-
to Antarctodius antarcticus (Watling ceedings ofthe Biological Society ofWashing-
Holman, 1981), the only otherochlesid spe- ton 94:181-227.
