Eight New Species Of Ligophorus Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae) From Mugilids Off Peninsular Malaysia
Author
Lim, O. Y. M. Soo L. H. S.
text
Raffles Bulletin of Zoology
2012
2012-08-31
60
2
241
264
journal article
10.5281/zenodo.13256712
2345-7600
13256712
Ligophorus navjotsodhii
,
new species
(
Fig. 7i, 7A–F
)
Type-host
.
—
Liza subviridis
Valenciennes
Type-locality
.
—
Off Carey Island
,
Banting
,
Malaysia
(
2°51'N
,
101°22'E
)
Type specimens
.
—
Holotype
:
NHMUK 2012.7
.2.1
Paratypes
:
6 paratypes
NHMUK
2012.7.2.2–
7 in
the
Natural History Museum
,
London
;
1 paratype
ZRC
.PAR.02 in the
Raffles Museum of Biodiversity Research
,
National University
of
Singapore
;
41 paratypes
MZUM
(P)2012.444(P)–484(P) in the
University of Malaya
collection
.
Material studied
.
—
49 specimens
studied;
49 specimens
measured.
Etymology
.
— This species is named in honour of the late Prof. Navjot S. Sodhi, National University of
Singapore
,
Singapore
for his contribution to Science.
Description
.
— Body elongate, 600 (382–801) × 97 (61–134) (n = 49), 3 pairs of head organs, 2 pairs pigmented eye spots, posterior with lenses and bigger than anterior pair. Mouth subterminal, ventral; pharynx ovoid, 31 (24–34) × 31 (24–35) (n = 49); intestine bifurcates posterior to pharynx, rejoins posterior to testis and anterior to peduncle forming cyclocoel. Haptor well demarcated; size 91 (59–136) × 109 (63–158) (n = 49); 14 larval
type
marginal hooks, similar, length 13 (11–15) (n = 49); two pairs of anchors; 2 dorsal anchors, inner length 36 (33–41) (n = 49), outer length 35 (31–38) (n = 49), inner root 14 (12–15) (n = 49), outer root 8 (6–9) (n = 49), point 6 (4–9) (n = 49); 2 ventral anchors, inner length 36 (32–39) (n = 49), outer length 37 (34–39) (n = 49), inner root 14 (11–16) (n = 49), outer root 9 (7–10) (n = 49), point 7 (5–8) (n = 49); 2 connecting bars: V-shaped dorsal bar, 33 (29–36) × 5 (4–6) (n = 49); ventral bar inverted V-shape, 33 (29–39) × 8 (5–9) (n = 49), AMP consisting of two membranous lateral pieces and a flattened median piece, distance between lateral pieces, 7 (6–10) (n = 49). Testis single, elongate ovoid, postero-dorsal to ovary; posterior region prominent, cells spermatozoa in anterior region, vas deferens leaves anterior region of testis, to sinistral-ventral side, ascends intercaecally, distending, forming seminal vesicle, narrows as vas efferens to enter into smaller lobe of bilobed initial part of copulatory tube. Single elongate gourdshaped prostatic reservoir with prostatic duct leaving reservoir to enter bilobed initial of copulatory tube. Copulatory organ consists of copulatory tube, length 71 (63–96) (n = 49) with bilobed initial part and two opposing accessory pieces; an elongate groove piece, 27 (22–30) (n = 49) and similar length elongate non-groove piece with distal hook. Ovary elongate with recurved posterior region, J-shaped (
Fig. 7i
), anterior end narrows to form oviduct, continues anteriorly as oötype surrounded by Mehlis’ gland; proceeds anteriorly as uterus to open near copulatory tube opening. Vagina and vaginal tube not observed, prominent sperm-filled seminal receptacle at midbody dorsal to ovary, duct from seminal receptacle to oviduct not observed in this species. Vitellarium in lateral fields approximately co-extensive with intestinal caeca, confluent just posterior to intestinal bifurcation, just anterior to ovary and just posterior to cyclocoel.
Fig. 4. Dendrogram of 50
Ligophorus
species
based on characteristics of the bars (abbreviations for new species as in Fig. 3).
Fig. 5. Dendrogram of 50
Ligophorus
species
based on the accessory piece of the copulatory organs (abbreviations for new species as in Fig. 3).
Fig. 6. Dendrogram of 50
Ligophorus
species
based on the AMP of the ventral bar (abbreviations for new species as in Fig. 3).
Fig. 7.
Ligophorus navjotsodhii
,
new species
. 7i, composite illustration of entire worm (dorsal view). 7A–F, sclerotised hard parts: A, dorsal anchors; B, dorsal bar; C, ventral anchors; D, ventral bar (two forms); E, marginal hook; F, male copulatory organ.
Differential diagnosis
.
— The scatterplot shows that the
49 specimens
of
L. navjotsodhii
,
new species
are clustered together and closely associated with
L. chelatus
,
new species
and
L. funnelus
,
new species
(
Fig. 2
) in having metrically similar haptoral hard parts as well as copulatory tube. The NT analyses (
Table 2
) also indicate that
L. navjotsodhii
,
new species
is similar to
L. chelatus
,
new species
in having similar anchors and two opposing accessory pieces, but they differ in the distal end of the non-grooved part of the accessory piece; hook-like in
L. navjotsodhii
,
new species
and claw-like in
L. chelatus
,
new species
(
Figs. 7F
,
8F
).
L. navjotsodhii
,
new species
differs from
L. funnelus
,
new species
in having two opposing accessory pieces compared to the single funnel-shaped accessory piece in
L. funnelus
,
new species
(
Figs. 7F
,
9F
). The NT analyses (
Table 2
) also show that
L. navjotsodhii
,
new species
is similar to
L. careyensis
,
new species
in having similar
types
of anchors, accessory piece and AMP, to
L. llewellyni
in the structure of the anchors, bars and AMP, to
L. euzeti
in anchors and bars, to
L. zhangi
in bars and AMP and to
L. heteronchus
,
L. imitans
,
L. macrocolpos
,
L. minimus
,
L. mediterraneus
,
L. parvicirrus
,
L. pilengas
,
L. saladensis
, and
L. uruguayense
in the structure of the anchors and AMP (
Table 2
).
L. navjotsodhii
,
new species
however differs from all these abovementioned species mainly in possessing a hook-like distal end of the non-grooved piece of the accessory piece (
Fig. 7F
).