Ligophorus grandis, Oym & Wb & Lhs, 2015

Oym, Soo, Wb, Tan & Lhs, Lim, 2015, Three new species of Ligophorus Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae) from Moolgarda buchanani (Bleeker) off Johor, Malaysia based on morphological, morphometric and molecular data, Raffles Bulletin of Zoology 63, pp. 49-65 : 61

Ligophorus grandis , new species

( Figs. 4E, F , 6A–F )

Type host. Moolgarda buchanani (Bleeker, 1853) .

Type locality. Straits of Johor, Peninsular Malaysia (01°2′6″N 103°5′4″E)

Materials examined. All specimens collected from the Straits of Johor, Peninsular Malaysia. Holotype: NHMUK 2014.11 .10.9, coll. Liew Kim Seng, 19 December 2013 . Paratypes: NHMUK 2014.11.10.10– 2014.11.12 , ZRC. PAR.45– ZRC.PAR.47 and MZUM (P) 2014.108(P)– 2014.122(P), coll. Liew Kim Seng, 19 December 2013 .

Etymology. This species is named after its size, being the largest Malaysian Ligophorus species.

Description. Body elongate, 1966 (1355–2167) × 321 (200–379), three pairs of head organs, two pairs pigmented eye spots, posterior with lenses and bigger than anterior pair. Mouth subterminal, ventral. Haptor well demarcated, size 96 (74–105) × 145 (123–159); 14 larval-type marginal hooks, similar, length 12 (10–13); two pairs of anchors; two dorsal anchors, inner length 44 (42–45), outer length 35 (34–37), inner root 21 (18–23), outer root 10 (7–12), point 11 (10–13); two ventral anchors, inner length 41 (39–43), outer length 39 (37–42), inner root 20 (18–22), outer root 12 (8–14), point 10 (8–10); two connecting bars: dorsal bar broad V, 54 (51–57) × 8 (6–9); ventral bar inverted V, 45 (43–49) × 12 (9–14), AMP consists of single bifurcated piece, distance between bifurcations, 3 (1–4). Testis single, elongate, ovoid, comparatively large, postero-dorsal to ovary, spermatozoa observed in anterior region. Single prostatic reservoir with prostatic duct leaving reservoir to enter bigger lobe of bilobed initial of copulatory tube. Male copulatory organ consists of copulatory tube, length 59 (52–63) with bilobed initial part and a grooved accessory piece with an expanded hook-shaped distal end 34 (31–40). Ovary J-shaped, large, elongate with recurved posterior region. Vaginal opening and tube not observed. 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. Ligophorus grandis , new species, is the largest Ligophorus species collected from Malaysian waters ( Table 1). Ligophorus grandis , new species, is most similar to L. johorensis , new species, and L. kedahensis based on NT analysis ( Fig. 2 ) but it can be differentiated from L. kedahensis and L. johorensis , new species, in the morphology of its AMP and accessory piece of the copulatory organ. Ligophorus grandis , new species, possesses a single bifurcating AMP ( Fig. 6D ), compared to a raised median piece with membranous lateral pieces in both L. kedahensis ( Soo & Lim, 2012) and L. johorensis , new species ( Fig. 5J ). In terms of the morphology of the accessory piece, L. grandis , new species, has a grooved accessory piece with an expanded hook-shaped distal end ( Fig. 6F ), compared to a simple grooved boat-like accessory piece in both L. kedahensis ( Soo & Lim, 2012) and L. johorensis , new species ( Fig. 5L ). Ligophorus grandis , new species, also differs from L. fenestrum in having non-fenestrated anchors ( Figs. 6A, C ) despite forming sister group with L. fenestrum in the MP trees ( Fig. 3 ). Ligophorus grandis , new species, is most similar to L. bykhowskyi in possessing similar anchors, dorsal bar and male accessory piece. However, L. grandis , new species, differs in possessing a single bifurcating AMP, a shorter ventral bar 45 (43–49), longer dorsal anchor points 11 (10–13) and longer ventral anchor points 10 (8–10) as compared to an AMP consisting of two membranous lateral pieces + a raised median piece, a longer ventral bar 49 (45–52), shorter dorsal anchor points 10 (9–10) and shorter ventral anchor points 7 (6–7) in L. bykhowskyi . It is also observed that L. grandis , new species, has a morphologically similar ventral bar to L. bipartitus but differs in having larger anchors, a longer male copulatory tube 59 (52-63) and longer accessory piece 34 (31–40) compared to smaller anchors, a shorter male copulatory tube 42 (38–45) and shorter accessory piece 24 (23–26) in L. bipartitus .

Figures

Fig. 4. Photomicrographs of the sclerotised hard parts Ligophorus liewi, new species (A & B), L. johorensis, new species (C & D) and L. grandis, new species (E & F). A, C & E, anchors and bars; B, D & F, male copulatory organ.

Fig. 6. Sclerotised hard parts of L. grandis, new species: A, dorsal anchors; B, dorsal bar; C, ventral anchors; D, ventral bar (dorsal view); E, marginal hook; F, male copulatory organ.

Fig. 2. Dendrogram of 62 Ligophorus species based on characteristics of all hard parts (anchors, bars and copulatory organ). The arrows on the far right indicate the positions of the three new species: L. liewi, L. johorensis and L. grandis.

Fig. 5. Sclerotised hard parts of L. liewi, new species (A–F) and L. johorensis, new species (G–L): A & G, dorsal anchors; B & H, dorsal bar; C & I, ventral anchors; D & J, ventral bar (dorsal view); E & K, marginal hook; F & L, male copulatory organ.

Fig. 3. Maximum-parsimony (MP) trees generated from (A) 28S dataset and (B) 28S+ITS1 dataset using PAUP* with Ergenstrema mugilis as the outgroup. Percentages of the bootstrap values are shown along the branches. *denotes new species