Ligophorus chelatus, 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 : 253

Ligophorus chelatus , new species

( Fig. 8i, 8A–G )

Type-host. — Liza subviridis Valenciennes

Type-locality. — Off Carey Island , Banting, Malaysia (2°51'N, 101°22'E)

Type specimens. — Holotype: NHMUK 2012.7 .2.8

Paratypes: 5 paratypes NHMUK 2012.7.2.9– 13 in the Natural History Museum , London ; 3 paratypes ( ZRC.PAR.05) and 2 paratypes ( ZRC. PAR.08) in the Raffles Museum of Biodiversity Research , National University of Singapore ; 39 paratypes MZUM (P)2012.278(P)– 316(P) in the University of Malaya collection .

Material studied. — 50 specimens studied; 50 specimens measured.

Etymology. — This species is named after the claw-like accessory piece.

Description. — Body elongate, 610 (382–801) 95 (52–134) (n = 50), pharynx size 31 (24–37) × 31 (24–35) (n = 30). Head-organs, eye-spots and alimentary system as in L. navjotsodhii , new species. Haptor well demarcated; size 92 (55–148) × 115 (63–165) (n = 50); 14 larval type marginal hooks, length 13 (11–16) (n = 50); two pairs of anchors; 2 dorsal anchors, inner length 38 (33–41) (n = 50), outer length 37 (30–40) (n = 50), inner root 14 (12–17) (n = 50), outer root 8 (6–10) (n = 50), point 6 (4–8) (n = 50); 2 ventral anchors, inner length 36 (32–39) (n = 50), outer length 38 (30–41) (n = 50), inner root 14 (11–16) (n = 50), outer root 9 (7–11) (n = 50), point 7 (5–10) (n = 50); 2 connecting bars: V-shaped dorsal bar, 34 (29–41) × 5 (4–7) (n = 50); ventral bar inverted W, 35 (29–40) × 8 (6–10) (n = 50), AMP with two membranous lateral pieces and raised median piece, distance between lateral pieces, 7 (5–11) (n = 50). Soft anatomical male reproductive system as in L. navjotsodhii , new species. Copulatory organ consists of copulatory tube, length 70 (59–80) (n = 50) with bilobed initial part and two opposing accessory pieces; an elongate groove piece 26 (21–31) (n = 50) and similar length non-groove piece with distal claw. Soft anatomical female reproductive system as in L. navjotsodhii , new species except vagina is sclerotised, vaginal opening median at level of recurved portion of ovary, vaginal tube sclerotised, length 34 (30–37) (n = 10), leading to ovoid seminal receptacle.

Differential diagnosis. — Based on the PCA ( Fig. 2 ) and NT analyses ( Table 2), L. chelatus , new species is similar to L. navjotsodhii , new species in having anchors of similar shape and size and two opposing accessory pieces, but the two species are different in the distal end of the non-grooved part of the accessory piece; claw-like in L. chelatus , new species and hook-like in L. navjotsodhii , new species ( Figs. 8F , 7F ). L. chelatus , new species and L. navjotsodhii , new species are grouped with L. funnelus , new species in the PCA scatterplot ( Fig. 2 ) based on similarities in measurements of their anchors, bars and copulatory tube but L. chelatus , new species differs from L. funnelus , new species in having two opposing accessory pieces instead of the funnel-like accessory piece of L. funnelus , new species ( Figs. 8F , 9F ) and from L. navjotsodhii , new species in having a claw-like distal end instead of hook-like distal end of the non-grooved opposing accessory piece ( Figs. 8F , 7F ). The NT analyses grouped L. chelatus , new species with L. careyensis , new species based on similarities in the structure of the anchors, bars and accessory piece, with L. parvicirrus and L. minimus in the anchors and bars and with L. cephali , L. chabaudi , and L. mugilinu s in the structure of the anchors and AMP ( Table 2). However L. chelatus , new species differs from all these abovementioned species in having two opposing accessory pieces and from L. careyensis , new species in having the non-grooved opposing piece with a distal claw ( Fig. 8F ) instead of a distal fork ( Fig. 12F ).

Figures

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. 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. 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. 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.

Fig. 12. Ligophorus careyensis, 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.