2 New Species Of Podocerus Leach (Crustacea, Amphipoda, Podoceridae) From Bermuda

14 Pages·1994·3.6 MB·English

by  A J Baldinger

PROC. BIOL. SOC. WASH.
107(4), 1994, pp. 707-720
TWO NEW SPECIES OF PODOCERUS LEACH
(CRUSTACEA: AMPHIPODA: PODOCERIDAE)
FROM BERMUDA
Adam J. Baldinger and Michael F. Gable
Abstract.—Twonewspecies,PodocerustachyrheoandPodoceruslazowasemi,
are described from Bermuda. Podocerus tachyrheo is a non-carinate, highly
pigmented species lackinguropodalinterramal spines; P. lazowasemipossesses
distinct uropodal interramal spines and dorsal carinations, but usually lacks
pigmentation.
In Kunkel's (1910) monograph on the 2withdorsalspinegroupsonly.Adultmales
amphipodsofBermudanospecimensofthe and females with varying degrees of pig-
genus Podocerus were recorded. Johnson mentation. Coxal plates 1-5 with a strong
(1986) and Gable et al. (1988), however, distal spine. Male antennae 1-2, gnatho-
bothrefertotheexistenceofasinglespecies pods 1-2, maxillae 1-2, mandibular palp,
ofPodocerus in Bermuda. Examination of and maxilliped with plumose setae. Male
collections at the Yale Peabody Museum antenna 2, flagellum 3-articulate and or-
(YPM)andattheNationalMuseumofNat- namentedwith submarginal spines. Female
uralHistory(USNM)clearlydocumentsthe antennae 1-2, gnathopod 1, maxillae 1-2,
presenceoftwo speciesofPodocerusin Ber- mandibular palp, and maxilliped with plu-
muda, both of which are newly described mose setae. Male gnathopod 2, article 5
in this paper. masked by articles 4 and 6, palm with ir-
In the figures, body parts are marked by regular margin bearing a proximal conical
abbreviations as follows: A, antenna; Gn, tooth and a distal rectangular process. Ar-
gnathopod; LL, lower lip; Md, mandible; ticle 6 ofallpereopodswith strongbifurcate
Mx, maxilla; Mxpd, maxilliped; P, pereo- spines. Uropods 1-2 with bifurcate spines
pod; T, telson; U, uropod; UR, urosome. but lacking peduncular interramal spines.
Description.—Male: Body and append-
Podocerus tachyrheo, new species ageswithpigmentation,bodylackingdorsal
Figs. 1-5 carinae,pereonsegments5-7andpleonseg-
ments 1-2 with dorsal distoposterior spine
Podocerus sp.—Johnson, 1986:378, fig.
groups, pereon segments 5-7 also with lat-
125.-Gableetal., 1988:148-149.
eral distoposterior spine groups. Coxae re-
Etymology.—Namedfortheabilityofin- duced with serial discontiguity, coxae 1-5
dividuals ofthis species to live in areas of each with a large marginal spine, located
extremely swift (G. tachy-) currents (G. anteriorly on coxae 1—4. Head less than pe-
rheo), suchasthoseatTheFlatts, Bermuda, reonites 1 and 2 in length, cuboidal with
whereall tidal flow from Harrington Sound ocular bulges. Eyes pigmented.
moves through one narrow channel. Antenna 1, 33% oftotal body length, pe-
Diagnosis.—hereon without dorsal cari- duncularratio 1:3:2.7,flagellum 5-articulate;
nations. Pereon segments 5-7 with dorsal accessory flagellum 1-articulate and prom-
andlateral spinegroups, pleon segments 1- inent. Antenna 2 greater than antenna 1 in
'
708 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
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Fig. L Podocerustachyrheo, male, 4.0 mm, YPM No. 9239.
length, articles 4 and 5 subequal, flagellum er plate reaching 50% length ofpalp, with
3-articulate with distinct submarginal an inner marginal spine row and submar-
spines. ginal setae; palp 4-articulate, terminal ar-
Mandible with 3-segmented palp, pen- ticle triangular. Lower lip, normal.
ultimatearticletriangularwith marginal se- Gnathopod 1, coxal plate rhomboidal
tae, terminal article clavate with facial and withadistinctdistoanteriorspine; article 6,
apical setae; incisorand lacinia both with 4 palmar margin longer than hind margin;
teeth; spine row of 3 short, broad spines; dactyl with 3 marginal setae. Gnathopod 2
molar normal. Maxilla 1, inner plate ves- heavilypigmented, robust, and muchlarger
tigial;outerplatewith9strongapicalspines; than gnathopod 1; article 5 hidden behind
palp 2-articulate, terminal article with 3 articles 4 and 6; palm ofarticle 6 with ir-
apical, medially bulging spines and 1 apical regular margin, bearing a proximal conical
seta,4submarginalsetae,and4facialspines. tooth and adistal rectangular process, mar-
Maxilla 2, outer plate with 10 long apical gin heavily setose with 2 proximal spines.
setae; innerplate with 1 apical setae, inner Basesofpereopods3-7withposteriorplate-
margin with fine setae distally. Maxilliped, like extensions; article 6 of all pereopods
inner plate with marginal and submarginal with distally bifurcate spines.
setaeandasingleoutermarginal spine; out- Uropods 1 and 2 elongate, biramous.
VOLUME 107, NUMBER4 709
Fig. 2. Podocerus tachyrheo. male, 4.0 mm, YPM No. 9239: Al, Gnl, Gn2, UR (with left Ul, right U2,
rightand leftU3, T). Male, 2.9 mm, YPM No. 9242: A2.
710 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig. 3. Podocenistachyrheo, male, 4.1 mm, YPM No. 9241.
VOLUME NUMBER
107, 4 711
Fig. 4. Podocerustachyrheo, male, 2.9 mm, YPMNo. 9242: P3-P4. Male, 4.0 mm, YPMNo. 9239: P5-7.
lacking interramal spines; peduncles and body segment, even on the most distal an-
rami with marginal bifurcate spines, rami tennal segment. In females, however, pig-
with distinct apical spines. Uropod 3 leaf- mentation appears to become much denser
like with 3 apical setules. Telson dorsally on the ventral margin of the pereon, and
produced and armed with 4 long setae and mayextendtothebasalportionsoftheoos-
6 short setules. tegites. Male/femaledifferencesinbodyspi-
Female: All features same as those for nation, in the flagella ofboth antennae, in
male except as noted. Body lacking dorsal both gnathopods, and in pigmentation ob-
spinegroups. Antenna 1, 40% oftotal body viously make P. tachyrheo sexually dimor-
length; flagellum 4-articulate. Flagellum of phic.
antenna 2 lacking distinct submarginal Podocerus tachyrheo is morphologically
spines. Gnathopod 1, article 6, proximal most closely related to Podocerus muhis-
comer of palm demarcated by a spine. pinis K. H. Barnard, 1925 and Podocerus
Gnathopod 2 resembling gnathopod 1 but muhispinis var. levis K. H. Barnard, 1925.
twice the size and less ornamented. The only major difference between P. mul-
Remarks.—The, degree and patterns of tispinis and P. muhispinis var. levis is the
pigmentation are variable among individ- almost complete absence ofthe dorsal spi-
uals of P. tachyrheo; juveniles, smaller niform tubercles in the variety (Barnard
males, and females may completely lack 1925). Based upon the description and one
pigment. Largermalesappeartohaveauni- illustrationofgnathopod2bybothBarnard
form pigment band along the musculature (1925) and Griffiths (1976), the most sig-
of the pereon segments. Pigment has also nificantdifferencesbetweenP. tachyrheoand
been observed in males on almost every P. muhispinis are: the number of flagellar
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Fig. 5. Podocemstachyrheo, female, 3.0 mm, YPM No. 9240.
VOLUME 107, NUMBER4 713
YPM YPM
articles ofantenna 1, P. tachyrheowith five paratype, 9242 (same data as
and P. multispinis with eight; the lateral 9241), 2.9 mm. 1 female paratype, oviger-
YPM YPM
spinesonthepereon,presentinP. tachyrheo ous, 9244 (same data as 9243),
and absent in P. multispinis; the number of 3.5 mm, highly pigmented. 5 paratypes, 2
setaepresentonthetelson,fouronP. tachy- males, 2 females, ovigerous, and 1 juvenile,
rheoandtwoonP. multispinis; theirregular deposited by YPM in Bermuda Museum of
YPM
marginofthepalmofarticle6ofgnathopod Natural History (same data as 9243).
2, P. tachyrheowith onetoothandone rect-
angular process and P. multispinis, as de- Podocerus lazowasemi, new species
scribed by Barnard (1925), with two teeth Figs. 6-9
and one rectangular process. In addition, Etymology.—'Nz.v[\Qd. in appreciation for
Barnard (1925) does not mention P. mul- the technical assistance, sound advice, and
tispinis or the variety as having pigmenta- encouragement received for this and many
tion. Finally, although close morphologi- other projects from our colleague and good
cally to P. tachyrheo, P. multispinis is friend, E. A. Lazo-Wasem (YPM).
endemicfromNataltoSaldanhaBay, South Diagnosis.—Pereon segments 6-7 and
Africa (Griffiths 1975). Podocerus tachy- pleon segments 1-2 with dorsal carinations
rheo, therefore, maybeconsideredaspecies andspinegroups. Coxalplates 1-7 eachwith
endemic to Bermuda. 1 large marginal spine. Antennae 1-2, max-
Otherthanitsmorphology,littleisknown illae 1-2, maxilliped, and male gnathopods
aboutP. tachyrheo. In Bermuda most spec- 1-2 with plumose setae. Maxilla 1, outer
imens collected were associated with hy- plate with 8 apical spines. Male gnathopod
droids; one collection yielded several hun- 1, article 6 with anterior marginal setae;
dred specimens taken from a small portion gnathopod 2, palm at dactyl hinge with a
ofalargecolonialhydroid, Halocordyledis- pronounced rectangular process. Dactyls of
ticha (Goldfuss), found attached in an area all pereopods with a proximoanterior plu-
ofvery strong current. mose seta. Peduncle of uropods 1-2 with
Material examined. —Male holotype, interramal spine. Dorsal lobe oftelson with
YPM
9254, The Flatts, Harrington Sound, 2 long and 2 short setae.
Bermuda, M. F. Gable, 23 May 1989, 5.0 Description.—Male: Body unpigmented
mm, onHalocordyledisticha (Goldfuss) at- with conspicuous dorsal carinae and dorsal
tached to a subtidal pipe. Female allotype, spine groups on pereon segments 6-7 and
YPM
9245, The Flatts, Harrington Sound, pleon segments 1-2. Coxae reduced with
Bermuda, M. F. Gable, 23 May 1989, 2.9 serial discontiguity, each with a large mar-
mm, mature, on Halocordyle disticha ginal spine. Head equal to pereonites 1-2
(Goldfuss)attachedtoasubtidalpipe. 1 male in length, cuboidal with lateral ocular bulg-
YPM
paratype, 9239, Harrington Sound, es. Eyes pigmented.
behind Bermuda Aquarium, Bermuda, M. Antenna 1, 40% oftotal body length, ge-
F. Gable, 2 Jun 1987, 4.0 mm, within hy- niculate, article 2 slightlylongerthanarticle
droids and algae. 1 female paratype, YPM 3, flagellum 5-articulate; accessory flagel-
9240, (same data as YPM 9239), 3.0 mm. lum, 1-articulate and prominent. Antenna
20 paratypes, males, females andjuveniles, 2, bigeniculate, article 5 nearlytwiceaslong
YPM
9243,LongBirdCauseway, Bermuda, as article 4, flagellum 4-articulate and or-
Ssideandundercauseway,E.A. Lazo-Was- namented with spines and setal groups.
em, 20 Jun 1988, washing ofrocks. 1 male Mandible with 3-segmented palp, pen-
YPM
paratype, 9241, TheFlatts, Bermuda, ultimate segment with submarginal and
M. F. Gable, 23 May 1989, 4.1 mm. 1 male marginal setae, terminalarticleclavatewith
714 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig.6. Podoceruslazowasemi, male, 3.0mm,YPMNo.9260: body,Gnl,Gn2.Female,2.4mm,YPMNo.
9261:Gnl,Gn2.
facial and apical setae; incisorwith 4 teeth; 9 apical setae. Maxilliped, inner plate cla-
lacinia with 5 teeth; spine row of 3 short, vatewithapicalandfacialsetae,distalinner
broad spines; molar normal. Maxilla 1, in- comer with a large marginal spine; outer
ner plate vestigial; outerplate with 8 strong plate <50% length of palp, with 4 inner
apical spines, 2 of them bifurcate; palp marginal spines and with submarginal and
2-articulate, terminal article with 4 strong marginal setae; palp 4-articulate with sub-
apical spines and 3 apical setae. Maxilla marginal and marginal setae. Lower lip,
2, inner plate with 10 apical setae, inner normal.
marginlinedwithfinesetae;outerplatewith Gnathopod 1, coxal plate rhomboidal
VOLUME 107, NUMBER4 715
Fig. 7. Podoceruslazowasemi, male, 3.3 mm,YPMNo. 9262: Al,A2. Male, 3.1 mm,YPMNo. 9259: UR
(with right Ul, left U2, rightand leftU3, T).
716 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
Fig. 8. Podoceruslazowasemi, male, 3.3 mm, YPM No. 8357.
with 1 large distoanterior spine; article 6, pod 2 robust and much larger than gnatho-
palm much longer than hind margin and pod 1; basis triangulate, formed by a dis-
with marginal setae, anterior margin with 4 toanterior lobed projection; article 6, palm
setal groups; dactyl with 4 marginal setules setose with a pronounced distal rectangular
and a subterminal bifurcate spine. Gnatho- processand4distinctsubmarginalbifurcate