Ligophorus navjotsodhii, Lim, 2012

Lim, O. Y. M. Soo L. H. S., 2012, Eight New Species Of Ligophorus Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae) From Mugilids Off Peninsular Malaysia, Raffles Bulletin of Zoology 60 (2), pp. 241-264 : 251-253

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.

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 ).

Figures

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.

Fig. 2. Principle Component Analysis (PCA) scatterplot of 318 Ligophorus specimens.The vertical and horizontal bar plots indicate one-dimensional summary of the principle component axes.

Fig. 8. Ligophorus chelatus, new species. 8i, composite illustration of entire worm (dorsal view). A–G, sclerotised hard parts: A, dorsal anchors; B, dorsal bar; C, ventral anchors; D, ventral bar (two forms); E, marginal hook; F, male copulatory organ; G, vaginal opening and seminal receptacle.

Fig. 9. Ligophorus funnelus, new species: A, dorsal anchors; B, dorsal bar; C, ventral anchors; D, ventral bar (two forms); E, marginal hook; F, male copulatory organ; G, vaginal opening and seminal receptacle.