Three new species of copepods (Copepoda: Calanoida and Cyclopoida) from anchialine habitats in Indonesia
Author
Boxshall, Geoff A.
Author
Jaume, Damià
text
Zootaxa
2012
3150
36
58
journal article
45716
10.5281/zenodo.279542
cbd16c95-0f9f-497f-a5da-e1bb750d66e9
1175-5326
279542
Paracyclopina sacklerae
n. sp.
(
Figs. 1–4
)
Type
material.
Holotype
female, 7
paratype
females, 5
paratype
males collected from sinkholes at Walengkabola village (
5º 11.052’ S
122º 35.159’ E
), Muna Island,
Indonesia
on
18 September 2007
by G.A. Boxshall and D. Jaume. Registration numbers:
holotype
[
MZB
.Cru Cop.103], 4
paratype
females and 3
paratype
males [
MZB
.Cru Cop.104] in Museum Zoologicum Bogoriense, 3
paratype
females and 2
paratype
males in Natural History Museum, London [
BMNH
2011.1167-1171].
Etymology.
The species is named in honour of Mrs Theresa Sackler in recognition of her long term philanthropic support of the research and education work of the Natural History Museum, London.
Description of adult female.
Body cyclopiform (
Fig. 1
A), divided into anterior prosome and posterior urosome with prosome–urosome boundary well defined at podoplean position. Prosome comprising cephalothorax and 4 free pedigerous somites; first pedigerous somite free, but partly concealed by posterior extension of dorsal cephalic shield. Epimeral angles of free second to fourth pedigerous somites rounded. Rostrum rounded, well developed. Nauplius eye not observed. Ratio of prosome to urosome length (including caudal rami) about 1.5:1. Urosome 5-segmented (
Fig. 1
B), comprising fifth pedigerous somite, genital double-somite formed by fusion of genital and first abdominal somites, and 3 free abdominal somites. Genital apparatus comprising paired copulatory pores located within dorsolateral gonopores: seminal receptacles paired (
Fig. 1
B). Egg sacs paired (
Fig. 1
A), containing 7 to
9
eggs. Mean body length
0.549 mm
, range
0.524 to 0.573 mm
(based on
5 specimens
).
Caudal rami (
Fig. 1
B) 56μm long by 43μm wide, about 1.3 times longer than wide and bearing 6 caudal setae (seta I absent). Seta II plumose, 60 – 65 μm in length; outer distal angle seta III plumose, ca. 71–80 μm, but shorter than inner distal angle plumose seta VI (85–97 μm); inner apical seta V (268–274 μm) longer than outer apical seta IV (189–227 μm); dorsal seta VII plumose and 61–73 μm long.
Antennule 17-segmented (
Fig. 1
C); probable segmental homologies as follows: segment 1 (I–II) double, segment 2 (III–V) compound, segment 3 (VI–IX) compound, segment 4 (X) free, segment 5 (XI) free, segment 6 (XII–XIV) compound, segment 7 (XV–XVI) double, segments 8 (XVII) to 16 (XXV) all free, apical segment 17 (XXVI–XXVIII) compound. Setal armature comprising: 3, 5, 7, 2, 2, 4, 2, 1, 1, 0, 1, 1 + aesthetasc, 1, 1, 1 + 1, 1 + 1, 6 + aesthetasc. Apical aesthetasc and adjacent seta arising from common base.
Antenna (
Fig. 2
A) uniramous; with coxa and basis fused and separated from first endopodal segment by nonfunctional articulation; coxa-basis armed with long plumose inner seta and short outer seta representing exopod; endopod 3-segmented; first endopodal segment with 1 inner margin seta, second segment with 5 setae, the shortest and most proximal separated by gap from other 4, third endopodal segment with 7 setae; first endopodal segment ornamented with spinules on inner surface; second and third endopodal segments each ornamented with row of spinules adjacent to outer margin, second segment with additional transverse spinule row.
Labrum (
Fig. 2
B) ovoid, with entire posterior margin; surface ornamentation of spinules on raised anterior zone.
Mandible (
Fig. 2
C–D) comprising coxa with well developed gnathobase bearing numerous blades along oblique margin, and biramous palp: palp consisting of large basis bearing single plumose seta, 2-segmented endopod with 3 + 5 setae, and 4-segmented exopod bearing total of 5 sparsely plumose setae [figured specimen with only 4 exopodal setae, missing seta indicated by arrow in
Fig. 2
C].
Maxillule (
Fig. 2
E) with large praecoxal arthrite bearing 8 marginal setal elements; coxal endite bearing single setae; coxal epipodite represented by long plumose seta; basis produced into 2 endites medially bearing 3 (proximal) and 2 (distal) spinulose setae; endopod comprising single expressed segment bearing 1, 1, 5 spinulose setae; exopod 1-segmented with 4 long plumose setae.
Maxilla well developed, 5-segmented (
Fig. 2
F); praecoxa and coxa incompletely separated, bearing 4 inner margin endites, armed with 3, 1, 3, 2 spinulose setae (from proximal to distal); basis bearing powerful claw-like element and spinulose seta, ornamented with spinule rows; endopod 3-segmented, bearing 4, 1, 3 setal elements (from proximal to distal).
Maxilliped (
Fig. 2
G) smaller than maxilla; 4-segmented; first segment (syncoxa) produced into two endites, proximal endite with 3 spinulose setae, distal endite armed with 2 setae and ornamented with row of spinules; second segment (basis) with 2 spinulose setae and row of spinules; endopod 2-segmented, first endopodal segment with 2 unequal spinulose setae and second with 4 spinulose setae.
Legs 1 to 4 biramous, with 3-segmented rami (
Fig. 3
A–C) and with intercoxal sclerites present; free posterior margins of sclerites smoothly rounded, lacking any ornamentation on either surface in legs 1 to 3; intercoxal sclerite of leg 4 with 2 spinule rows on posterior surface. Spine and seta formula as follows:
coxa basis exopodal segments endopodal segments
leg 1 0-1
1-I
I-1
;
I-1
; III,I,4 0-1; 0-1; 1,2,3
leg 2 0-1 1-0
I-1
;
I-1
; III,I,5 0-1; 0-2; 1,2,3
leg 3 0-1 1-0
I-1
;
I-1
; III,I,5 0-1; 0-2; 1,2,3
leg 4 0-1 1-0
I-1
;
I-1
; II,I,5 0-1; 0-2; 1,2,2
Coxa with spinule rows near outer distal angle in all legs (transversely orientated in leg 1 only); additional spinule rows present on coxa and basis of leg 4 only (
Fig. 3
C). Outer margin spines on all exopods and inner spine on basis of leg 1 bilaterally ornamented with strips of serrated membrane. Inner margin of basis of legs 1 to 4 and outer margins of all endopodal segments ornamented with row of setules; outer margins of all exopodal segments ornamented proximally with row of spinules. Spinule rows located at articulation between all endopodal and exopodal segments. Terminal spine on exopod of leg 4 very powerfully developed (
Fig. 3
C); spine 39μm in length with base 13μm in width, and 1.15 times longer than segment (length 34μm).
FIGURE 1.
Paracyclopina sacklerae
n. sp.
, adult female. A, habitus of ovigerous holotype female, dorsal; B, urosome (with dorsal caudal seta omitted), ventral; C, antennule. Scale bars: A = 100 μm, B, C = 50 μm.
FIGURE 2.
Paracyclopina sacklerae
n. sp.
, adult female. A, antenna; B, labrum, ventral; C, mandibular palp, with position of missing seta shown by arrow; D, biting edge of mandibular gnathobase; E, maxillule; F, maxilla; G, maxilliped. All scale bars = 50 μm.
FIGURE 3.
Paracyclopina sacklerae
n. sp.
, adult female. A, leg 1, anterior; B, leg 2, anterior; C, leg 4, anterior. All scale bars = 50 μm.
FIGURE 4.
Paracyclopina sacklerae
n. sp.
, adult male. A, habitus, dorsal; B, genital somite, ventral; C, antennule, with 2 segments distal to geniculation shown disarticulated; D, leg 5, ventral. Scale bars: A = 100 μm, B, C = 50 μm, D = 25 μm.
Fifth legs located ventro-laterally, comprising basal part incorporated into pedigerous somite armed with outer seta on small papilla and free exopodal segment (
Fig. 1
B). Outer basal seta visible in dorsal view (
Fig.1
A). Free exopodal segment 35μm long by 15μm in maximum width (measured at level of base of lateral spine), about 2.3 times longer than wide; bearing lateral margin spine (21μm long), outer distal spine (17μm), plumose apical seta (39μm) and inner distal spine (12μm); exopodal segment ornamented with sparse row of spinules along inner margin.
Description of adult male.
Body cyclopiform (
Fig. 4
A), divided into anterior prosome and posterior urosome as in female. Epimeral angles of free third pedigerous somites slightly produced. Ratio of prosome to urosome length (including caudal rami) about 1.7:1. Urosome 6-segmented, comprising fifth pedigerous somite, genital somite and 4 free abdominal somites. Genital somite (
Fig. 4
B) bearing paired genital openings ventrally. Caudal rami (
Fig. 4
A) 20μm long, by 16μm wide, about 1.25 times longer than wide and bearing 6 caudal setae (seta I absent), relative lengths of setae as for female. Mean body length
0.430 mm
, range
0.408 to 0.461 mm
(based on
3 specimens
).
Antennules (
Fig. 4
C) symmetrical, geniculate, 17-segmented; probable homologies: I–II, III–V, VI–VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX–XX, XXI–XXIII, XXIV–XXVIII; segment 11 (XV) with expanded sheath partly enclosing segment 12 (XVI). Setal armature comprising: 3, 4, 3, 2, 2, 0, 2, 1, 2, 1, 0, 1 (unilaterally spinulate), 1, 1 (unilaterally spinulate), 1 modified (fused to segment), 1 + 1 modified (fused to segment), 6 + aesthetasc.
Antennae to maxillipeds, and legs 1 to 4, as in female.
Fifth legs (
Fig. 4
D) as in female except free exopodal segment 22μm long by 9μm in maximum width (measured at level of base of lateral spine), about 2.4 times longer than wide; bearing lateral margin spine (13μm long), outer distal spine (20μm), plumose apical seta (29μm) and inner distal spine (28μm); inner margin of segment smooth.
Remarks.
The genus
Paracyclopina
was established in 1935 by
Smirnov (1935)
who designated his new species
P. nana
Smirnov, 1935
as the
type
species. At that time, the genus was included within the
Cyclopinidae Sars, 1913
, a heterogeneous and probably paraphyletic family deliberately retained by
Boxshall & Halsey (2004)
even though proposals had already been made by
Martínez Arbizu (2000a
,
b
,
2001a
,
b
) to break it up to form four other families, the
Cyclopettidae Martínez Arbizu, 2000
,
Giselinidae Martínez Arbizu, 2000
,
Hemicyclopinidae Martínez Arbizu, 2001
and
Psammocyclopinidae Martínez Arbizu, 2001
. Subsequently
Martínez Arbizu (2006)
proposed a fifth new family, the
Schminkepinellidae
, to include some other former members of the
Cyclopinidae
bringing the total number of “cyclopinid” families to seven (including the
Cyclopinidae
sensu stricto and the
Pterinopsyllidae
). No comprehensive parsimony based test of the validity of the new families derived from the break up of the
Cyclopinidae
has yet been carried out. Indeed, no other publications have addressed this issue except
Karanovic (2008)
who considered that characters exhibited by the new cyclopinids he was describing from
Australia
exposed more of the characters used to support the break up of the
Cyclopinidae
sensu lato
as unreliable and he recognised only the family
Cyclopinidae
. Clearly, uncertainty remains over the validity of some of these lineages as family level taxa.
Although its relationships with the family
Oithonidae Dana, 1853
remain to be resolved, the
Cyclopettidae
is reasonably well supported and is recognised here. When he established the
Cyclopettidae,
Martínez Arbizu (2000a)
tentatively included
Paracyclopina
as
incertae sedis
in his new family. Such caution was justified since all four of the species attributed to this genus were inadequately described. The four species recognised by
Martínez Arbizu (2000a)
as belonging to
Paracyclopina
were:
P. nana
,
P. intermedia
(
Sewell, 1924
)
,
P. l o ng if urc a
(
Sewell, 1924
) and
P. m i n u t a
(
Sewell, 1934
). The key characters used to support placement of
Paracyclopina
in a lineage with
Cyclopetta
Sars, 1913
were the 2-segmented endopod of the maxilliped and the lateral location of the leg 5 which comprises, in both sexes, one free exopodal segment carried on a slight pedestal representing the protopodal part of the limb that is incorporated into the somite.
Martínez Arbizu (2000a)
pointed out that the transformation of the inner apical and two outer margin spines on the exopod of leg 5 into setae was a synapomorphy of the core group of genera
Cyclopetta
,
Paracyclopetta
Wells, 1967
and
Arctocyclopina
Mohamed & Neuhof, 1985
. This transformation is not shared by
Paracyclopina
species, but the other synapomorphies support its placement in the
Cyclopettidae
(
Martínez Arbizu 2000a
).
Cyclopetta orientalis
Lindberg, 1941
was not mentioned by
Martínez Arbizu (2000a)
: it was neither treated as a species of
Cyclopetta
, nor transferred to any other genus within the
Cyclopinidae
sensu lato
. Although it was described as having a 1-segmented rather than a 2-segmented endopod on the maxilliped, it shares this form of laterally-located leg 5 and, in addition, has a 17-segmented antennule in the female, as in
P. nana
and
P. m i nu ta
. Accordingly
Cyclopetta orientalis
is here transferred to
Paracyclopina
as
Paracyclopina orientalis
(
Lindberg, 1941
)
n. comb.
It is assumed here that the description of the maxilliped is mistaken and that
P. orientalis
has a 2- segmented endopod as found in the new species.
The new species,
P. sacklerae
n. sp.
, is closely related to
P. orientalis
. Both species possess a strikingly robust terminal spine on the exopod of leg
4 in
both sexes and have three robust spines on the free exopodal segment of the female leg 5. No other
Paracyclopina
species share both of these features. There are several significant differences between these two species. Most obviously, the caudal rami are much shorter in
P. sacklerae
, only about 70% as long as the anal somite, whereas in
P. orientalis
the caudal rami are longer (125%) than the anal somite. The caudal rami themselves are more slender in
P. orientalis
, 3.5 times longer than wide compared to only 1.3 times longer than wide in
P. sacklerae
. Other differences include the shape of the antenna: in
P. sacklerae
the distal part of the antenna (second and third endopodal segments combined) is about equal in length to the proximal part (coxa-basis and first endopodal segment combined), whereas in
P. orientalis
the distal part is significantly shorter than the proximal part. The eggs sacs contained between 25 and 31 small eggs per sac in
P. orientalis
compared to 7 to 9 larger eggs per sac in the new species.
As highlighted by
Martínez Arbizu (2000a)
, all four species he ascribed to
Paracyclopina
were found in brackish to fresh waters.
Paracyclopina orientalis
, transferred to
Paracyclopina
here, was collected in shallow salty waters near to the coast at
Pondichery
(“des mares saumâtres peu profondes, près du bord de la mer à
Pondichéry
”) and in a lagoon at Oupalom (
Lindberg 1941
). It seems likely that this species also inhabits brackish waters. Finally, the new species was found in small sink holes, about
2 m
deep, located in the coastal limestone platform only
5 to 10 m
inland from the shoreline on Muna Island. During low tide many of the sinkholes appeared dry, but at high tide, water was clearly visible in most of them. The copepods were caught using a long-handled plankton net in a water column that was up to 50 or
60 cm
deep. Salinity measurements were not taken, but given the tidal influence and the proximity to the coast, it is highly likely that the water in the sinkholes was brackish but close to fully marine. The species of
Paracyclopina
appear to prefer low salinity and brackish water habitats, although
P. m i n u t a
was reported from “absolutely fresh” water in the
Hooghly
River, according to
Sewell (1934)
.
The genus is known only from the Indo-Pacific. Four
Paracyclopina
species were described from the coast of
India
:
P. longifurca
and
P. intermedia
were originally described from Chilka Lake (
Sewell 1924
) and the former is also known from the South
India
coast and from the canal system of the salt lakes at Chingrighatta (
Sewell 1934
);
P. minuta
is known from the
Hooghly
River which bounds the salt lakes and associated canal system near Chingrighatta (
Sewell 1934
);
P. orientalis
was collected at
Pondichery
and Oupalom (
Lindberg 1941
). The new species,
P. sacklerae
, is from
Indonesia
. The
type
species,
P. nana
, was described from the mouth of the Suifun river near Vladivostok (
Smirnov 1935
) and is also known from the coasts of
Japan
,
South Korea
and
China
(
Tai & Chen 1979
;
Chang 2009
;
Ueda
et al.
2001
).