Redescription of three cirolanid isopods (Crustacea: Peracarida) from Indonesia
Author
Sidabalok, Conni M.
Author
Bruce, Niel L.
text
Zootaxa
2016
4114
3
277
290
journal article
39012
10.11646/zootaxa.4114.3.4
73b07762-259c-4a13-812d-b5e218313615
1175-5326
271597
CB5BF831-138E-4606-B716-7EB894CC498D
Politolana stebbingi
(Nierstrasz, 1931)
comb. nov.
(
Fig. 7
)
Cirolana stebbingi
Nierstrasz, 1931: 154
, figs 24–29.—
Bruce, 1986
: 143
, 223.—
Brusca, Wetzer &
France
, 1995
: 18
.
Material examined.
Lectotype
♂ (
11.4 mm
) and
paralectotype
♂ (
15 mm
) here designated,
Siboga Expedition, Bajo Bay
,
Flores
,
0°34.6'N
,
119°8.5'E
. Station 88, 1301 m.
20 June 1899
(
ZMA
.
CRUS
.I.
100607
).
Supplementary description (male).
Body 3.5 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 5, lateral margins subparallel. Pereonite 1 and coxae 2–3 each with posteroventral angle rounded; coxae 5–7 with entire oblique carina; posterior margins of pereonites 5–7 smooth. Pleon with pleonite 1 visible in dorsal view; pleonites 3–5 posterior margin smooth; posterolateral angles of pleonite 2 forming acute point, not posteriorly produced; pleonite 3 with posterolateral margins extending to but not beyond posterior margin of pleonite 5, acute; posterolateral margin of pleonite 4 narrowly rounded, not extending beyond posterior margin of pleonite 5. Pleotelson 1.8 times as long as anterior width, dorsal surface without longitudinal carina; lateral margins straight, margins smooth, posterior margin evenly rounded, without median point, with 6 RS.
Antennula
flagellum extending to posterior margin of eye.
Antenna
peduncle article 4 1.5 times as long as wide, as long as article 3; article 5 1.1 times as long as article 4, 1.9 times as long as wide; extending to middle of pereonite 2.
Frontal lamina
narrow and slender, longer than greatest width, lateral margins straight, diverging slightly towards anterior, anterior margin rounded, without small median point.
Pereopod 1
basis 2.0 times as long as greatest width, superior distal angle with 1 acute seta; ischium 0.7 time as long as basis, superior distal margin with 5 acute RS; merus superior distal angle with 4 setae and 3 acute RS; carpus inferior margin with 1 small acute RS, superior distal margin with 1 large RS; propodus 1.9 times as long as wide, inferior margin with 5 acute RS, superior distal with 4 simple setae and 1 RS; dactylus 0.9 as long as propodus; inferior margin lacking setal fringe.
Pereopod 6
similar to pereopod 7.
Pereopod 7
basis 1.6 times as long as greatest width, superior margin weakly convex; ischium 0.8 as long as basis, inferior margin with 2 acute RS, superior distal angle with 6 RS (long), inferior distal angle with 4 RS (long); merus as long as ischium, 1.8 times as long as wide, inferior margin with 1 RS (single cluster), superior margin with 3 long slender setae, superior distal angle with 4 RS, inferior distal angle with 5 RS; carpus as long as ischium, 6.0 times as long as wide, inferior margin with 2 acute RS, superior distal angle with 4 RS, inferior distal angle with 4 RS; propodus 4.7 times as long as wide, inferior margin with 2 clusters of RS (sets as 1 and 2), superior distal angle with 2 slender setae, inferior distal angle with 1 slender seta.
Uropod
rami not extending beyond pleotelson, marginal setae in single tier, apices acute.
Endopod
apically not bifid; lateral margin distally concave; mesial margin strongly convex.
Exopod
not extending to end of endopod, apically not bifid; lateral margin convex; mesial margin convex.
Female
. No female specimens available.
Size.
Size of the male
lectotype
is 15.0 mm and
paralectotype
is
11.4 mm
.
Distribution.
Known only from the
type
locality, Bajo Bay,
Flores
.
Remarks.
The
type
material of
Politolana stebbingi
(Nierstrasz, 1931)
consists of two
syntypes
. We here designate the more intact specimen as
lectotype
. The age of the specimens and previous dissection meant that several characters could not be described, including the penial processes.
Politolana stebbingi
has a number of characters that do not conform with the diagnostic characters for
Cirolana
, such as the more elongate body, antenna peduncle articles 3 and 4 longest (vs 4 and 5 longest in
Cirolana
) and long and narrow frontal lamina (vs pentagonal, subquadrate or anteriorly round in
Cirolana
) (
Bruce, 1986
;
Brusca
et al.
1995
). Most of the diagnostic characters of
Politolana
listed by
Bruce (1981)
,
Wetzer
et al.
(1987)
and
Riseman & Brusca (2002)
, are present in
P. stebbingi
: the elongate body, long peduncle of pleopod 1 (also shared with
Plakolana
and
Odysseylana
), long, narrow and slender frontal lamina, flat and robust carpus of pereopod 7, long and acute robust setae on merus-propodus pereopod 1, small secondary unguis on dactylus of pereopods 1–3, short articles 1–2 of antenna peduncle and articles 3–5 longest and subequal, the presence of interocular furrow and produced posterolateral margin on pleonites 1 and 4.
FIGURE 7.
Politolana stebbingi
,
comb. nov.
, lectotype (15 mm) (A–F); paralectotype (G–H). A, dorsal view; B, lateral view; C, frons; D, antennal peduncle; E, head, dorsal view; F, pleotelson and uropods; G, pereopod 1; H, pereopod 7.
Several characters such as the less produced uropod peduncle medial margin, the absence of fringe of setae on the lateral margins of pleonites 2–4 and the presence of carina on pereonite 7 coxae separate
P. stebbingi
from
Politolana
sensu stricto
. Further, pereopod 1 of
P
.
stebbingi
differs from that of
Politolana
by not having the superodistal margin of the carpus as produced and in being less setose. Similarly, pereopod 7 differs by being less flat and the absence of dense setae. Overall,
Politolana stebbingi
shares more diagnostic characters with
Politolana
than
Cirolana
, therefore
Cirolana stebbingi
is considered as
Politolana
sensu lato
.
The captions for figures 26–29 on the original publication (
Nierstrasz, 1931b
) were incorrectly given as
Cirolana vanhöffeni
.