Ligophorus fenestrum, 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 : 260

Ligophorus fenestrum , new species

( Fig. 14A–F )

Type-host. — Valamugil buchanani Bleeker

Type-locality. — Off Langkawi Island , Kedah, Malaysia (6°21'N, 99°46'E)

Type-specimens. — Holotype: NHMUK 2012.7 .2.36

Paratypes: 3 paratypes NHMUK 2012.7.2.37– 39 in the Natural History Museum , London ; 2 paratypes ( ZRC.PAR.12) in the Raffles Museum of Biodiversity Research , National University of Singapore ; 21 paratypes MZUM (P)2012.1050(P)–1070(P) in the University of Malaya collection .

Materials studied. — 27 specimens studied; 27 specimens measured.

Etymology. — This species is named after the fenestration or windows on the anchors. Note that ‘fenestrum’ is a noun in apposition.

Description. — Body elongate, 1727 (1418–2027) × 270 (210–361) (n = 27), pharynx size 92 (77–105) × 94 (75–106) (n = 27). Head-organs, eye-spots and alimentary system as in L. navjotsodhii , new species. Haptor well demarcated, size 141 (104–192) × 129 (84–171) (n = 27); 14 larval type marginal hooks, similar, length 12 (11–14) (n = 27); two pairs of anchors; 2 dorsal anchors, inner length 38 (33–41) (n = 27), outer length 35 (31–37) (n = 27), inner root 19 (16–23) (n = 27), outer root 12 (8–16) (n = 27), point 11 (8–14) (n = 27); 2 ventral anchors, inner length 38 (34–40) (n = 27), outer length 36 (32–39) (n = 27), inner root 19 (14–22) (n = 27), outer root 13 (8–16) (n = 27), point 11 (9–13) (n = 27); 2 connecting bars: dorsal bar broad inverted U, 50 (41–57) × 7 (5–10) (n = 27); ventral bar horizontally straight 47 (43–52) × 8 (6–10) (n = 27), bifurcated median piece with no lateral pieces, distance between bifurcated piece, 4 (2–6) (n = 27). Copulatory organ consists of copulatory tube, length 86 (73–95) (n = 27) with bilobed initial part, ornamented on smaller lobe and boat-like simple grooved accessory piece, 34 (29–38) (n = 27). Vaginal opening and tube not observed.

Differential diagnosis. — L. fenestrum , new species is different from the other seven species as indicated by the PCA scatterplot ( Fig. 2 ). It is larger than L. kedahensis , new species, and in fact is the largest of the present Ligophorus species. This species is unique in possessing anchors with fenestrations, AMP is composed only of a bifurcated median piece without lateral pieces, a boat-like accessory piece and having the longest dorsal bar among all eight species ( Fig. 14A–D, F ). The NT analyses indicate that L. fenestrum , new species is similar to L. leporinus in the structure of the bars, grooved accessory piece and an AMP with bifurcated median piece without lateral pieces but L. leporinus lacks fenestrated anchors as in L. fenestrum , new species ( Fig. 14A, C ).

dorsal bar; C, ventral anchors; D, ventral bar; E, marginal hook; F,

male copulatory organ.

Figures

Fig. 14. Ligophorus fenestrum, new species: A, dorsal anchors; B, dorsal bar; C, ventral anchors; D, ventral bar; 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.