Sasala nolani, Bray, Rodney A., Cribb, Thomas H. & Littlewood, Timothy J., 2012

Bray, Rodney A., Cribb, Thomas H. & Littlewood, Timothy J., 2012, Sasala nolani gen. n., sp. n. (Digenea: Aporocotylidae) from the body-cavity of the guineafowl puffer fish Arothron meleagris (Lacepède) (Tetraodontiformes: Tetraodontidae) from off Moorea, French Polynesia, Zootaxa 3334, pp. 29-41 : 31

Sasala nolani sp. n.

( Figs. 1–7 )

Syns: ‘Unidentified sanguinicolid’ of Olson et al. (2003); ‘Sanguinicolid sp.’ of Lockyer et al. (2003) and Holzer et al. (2008); ‘unnamed blood flukes’ of Chen et al. (2008); ‘Sanguinicolid sp. Moorea–DTJL–2002’ of Alama-Bermejo et al. (2011); ‘DTJL 2000 ex Arothron ’ of Cribb et al. (2011).

Type-host. Arothron meleagris (Lacepède) ( Tetraodontiformes : Tetraodontidae ), guineafowl puffer fish.

Site. Body-cavity.

Type-locality. Off northern Moorea, French Polynesia (17°30’S, 149°50’W, 9/xii/1999; 19/xi/2009, 25/xi/ 2009 – eggs only).

Prevalence. 2 of 3 with worms.

Type-specimens. Holotype: MNHN HEL236, Paratypes MNHN HEL237–247, QM G 231091 - 231094, BMNH 2003.1.17.1-8.

GenBank numbers. ssrDNA AY157184 ; lsrDNA AY157174 .

Etymology. The specific name is for our colleague Dr Matthew J. Nolan of the University of Melbourne in recognition of his major contributions to aporocotylid systematics and phylogeny.

Description. Based on 22 specimens, measurements in Table 1 . Body lanceolate, willow leaf-like, thin (Figures 1, 3). Row of comb-like spines along ventral surface close to margins, no other spination ( Figure 4 ). Oral sucker small, without spines. Mouth ventrally subterminal. Oesophagus long, sinuous, anterior 25% (about) thinwalled ensheathed in narrow layer of gland-cells, about posterior 75% (about) thick-walled, middle 50% (about) ensheathed in distinct layer of gland-cells, posterior 25% (about) weakly ensheathed. Intestine X-shaped, anterior caeca shorter than posterior (but not greatly), in anterior half of body.

Testis single, large, reaches anteriorly between posterior caeca almost to intestinal bifurcation, intercaecal in this region, bulk posterior to caeca, wider in post-caecal region, margins irregular, texture reticulate (in 2 specimens testis overlaps posterior part of posterior caeca, where they curve inwards, in 1 specimen testes overlaps entire posterior-caeca). Vas deferens sinuous, passes from posterior part of testis, ventrally over ovary, into about mid-postovarian region, where it divides, one branch leads to cirrus-sac and other passes in arcuate course to close to posterior extremity, forming oval (apparently blind) auxiliary seminal vesicle ( Figures 2 , 5 ). Cirrus-sac elongate oval, internal duct may be swollen with sperm or narrow and sinuous. Short cirrus may protrude from genital pore. Male pore dorsal, sinistrally submedian, in anterior part of posterior half of post-ovarian region.

Ovary just post-testicular, multilobate, perforated probably by muscle bundles, deep indention at posterior margin. Oviduct arises from base of posterior indentation of ovary, small amounts of spermatozoa seen in distal part, passes posteriorly close to auxiliary seminal vesicle, recurved through Mehlis’ gland-cells, passing anteriorly becoming uterus. Uterus passes anteriorly almost to ovary, then recurves reaching to female pore, may be surrounded by gland-cell sheath distally, no distinct muscular metraterm developed. Eggs few, weakly tanned, become smaller with maturity, collapsed in stained and mounted specimens. Female pore dorsal, just anterior to male pore. Vitellarium follicular, follicles very numerous, anterior extent about 20% of oesophagus length from anterior extremity, posterior extent just posterior to ovary on poral side, further aporally, reaches close to margins, overlies intestine, testis and ovary ventrally, but not dorsally. Vitelline duct originates at about level of ovary, runs parallel and directly ventrally to oviduct before uniting with it close to its posterior extremity.

Excretory pore terminal. Small claviform excretory vesicle seen posterior to auxiliary seminal vesicle, remain- der of system not seen. Two ganglia lateral to oesophagus at about 25% of its length from anterior extremity, joined by wide ventral commissure.

Molecular phylogenetic analyses. For the data partitions the following proportion (number) of original alignment positions were retained by Gblocks: lsrDNA 49% (693), ssrDNA 70% (1397), ssrDNA+lsrDNA 68% (2245). The number of aporocotylids included in each analysis was lsrDNA:20, ssrDNA:9, ssrDNA_lsrDNA:8. The topology of each of the BI trees was consistent with respect to the relative placement of Sasala nolani , and thus here we show only the lsrDNA tree ( Fig. 7 ), since it includes the greatest taxonomic coverage. Nodal support was reasonably high (posterior probability> 0.95) throughout the lsrDNA phylogeny.

Figures

FIGURES 1 – 2. Sasala nolani n. gen., n. sp. 1. Ventral view of holotype, eggs stylized. 2. Terminal genitalia of paratype, vitelline follicles omitted, vitelline duct on top of oviduct, eggs stylized. Scale bars: 1, 500 µm, 2, 200 µm.

FIGURES 3 – 7. Sasala nolani n. gen., n. sp. 3. Wholemount. 4. Marginal spines. 5. Posterior extremity. 6. Lining of host gut, showing welts filled with aporocotylid eggs. 7. Section of welt showing enclosed eggs (arrowed). Abbreviations: asv, auxiliary seminal vesicle; cs, cirrus-sac; ee, early egg; ev, excretory vesicle; mt, metraterm; vd, vitelline duct, on top of oviduct. Scale bars: Scale bars: 3, 500 µm, 4, 20 µm, 5, 100 µm, 7, 50 µm.