Neopolystoma grossi, PREEZ, LOUIS H. DU & MORRISON, CHRISTA, 2012

PREEZ, LOUIS H. DU & MORRISON, CHRISTA, 2012, Two new polystomes (Monogenea: Polystomatidae) from the eyes of North American freshwater turtles, Zootaxa 3392 (1), pp. 47-59 : 52-55

Neopolystoma grossi n. sp.

( Figs. 5–7 )

Specimens studied: Three sexually mature worms. The holotype (NMB P341) and two paratypes (NMB P342– P343) are deposited in the Parasitic Worm Collection, National Museum, Aliwal Street, Bloemfontein, South Africa.

Type host: Pseudemys concinna floridana , sexually mature individual deposited in the Florida Museum of Natural History, Division of Herpetology, Museum Road, Dickinson Hall, University of Florida, Gainesville, Florida 32611 as a type host. Museum number: UF 141647.

Type locality: Pond at the United States Geological Survey USGS-BRD facility, Florida Integrated Science Centres, 7920 NW 71st Street, Gainesville FL 32653, USA (29.725278N; 82.417778W).

Site: Conjunctival cavity of the eye.

Etymology: This parasite is named after Dr. Timothy Gross who facilitated this study.

Description: Based on three egg-producing adults; measurements are given in micrometers. The average measurement is followed by the range given in parentheses. No larval measurements or characters are given, and although many eggs were harvested from the host, no development took place.

Adult: General characteristics given of mature, egg-producing parasite ( Figure 5 ). Body elongate, some stretched out, total length 4018 (3298–4873), greatest width 988 (911–1130), width at vagina 983 (900–1125), haptor length 769 (707–819), haptor width 891 (709–989); haptor length to body length ratio 0.2 (0.15–0.24); haptoral suckers 6, mean diameter 241 (208–244). Mouth subterminal, ventral. False oral sucker 403 (369–436) wide; pharynx length 222 (205–232), width 229 (209–246). Intestine bifurcate with no diverticula, right caecum 2453 (1877–3003) in length, left caecum 2290 (1923–2804) in length. No anastomoses; caeca do not join posteriorly and do not extend into the haptor. Testis compact, mid-ventral, medial, and posterior to ovary ( Figure 5 ). Seminal vesicle packed with sperm. Genital atrium median, ventral, posterior to intestinal bifurcation, 21 (12–24) in length with 6–8 spines, 8 (8–9) long. Ovary dextral, 25% from anterior end, ovary length 218 (210–222), width 128 (118–135). Short tubular uterus anterior to ovary, containing only one egg; egg capsule length 293 (288–301), width 139 (137–140). No intrauterine development, eggs operculate. Vitellarium situated in the first 70% of the body, forming no prehaptoral or haptoral anastomoses. Genito-intestinal canal obscured by the testis, located on the same side as ovary, joining intestinal caecum posterior to ovary ( Figure 5 ).

Remarks: Neopolystoma grossi n. sp. differs from N. elizabethae and N. fentoni by a combination of characteristics ( Table 1 ). With an average length of 4018 and a minimum length of 3298, N. grossi n. sp. is significantly longer than N. fentoni (with a maximum length of 2450), and even also N. elizabethae (with a maximum length of 3675). Neopolystoma grossi n. sp., with an average width of 988, is wider than N. fentoni , which has a maximum width of 760, and also possesses a slightly larger haptor. Neopolystoma grossi n. sp., with an average ovary size of 218 × 128, also differs from N. fentoni (with an average ovary size of 103 × 105), which is significantly smaller. N. grossi n. sp. can also be distinguished from N. elizabethae and N. fentoni by slightly smaller genital spines. Neopolystoma elizabethae , with a length of 322–367, possesses more elongated eggs than those of N. grossi n. sp. (with a length of 288–301). Neopolystoma grossi n. sp. can also be distinguished from N. elizabethae by a smaller haptoral sucker size of 241, as opposed to 372. Finally, N. grossi n. sp. has a smaller maximum haptor length to body length ratio of 0.20 that distinguishes it further from N. elizabethae (0.28) and N. fentoni (0.29).

Figures

FIGURE 5. Neopolystoma grossi n. sp. Ventral view of the holotype; the dotted line indicates the outline of the vitelline system. Abbreviations: eg, egg; gb, genital bulb; gi, genito-intestinal canal; hp, haptor; ic, intestinal caecum; mo, mouth; ov, ovary; ph, pharynx; su, sucker; te, testis; vd, vas deferens; vg, vagina; vi, vitellarium; vt, vitelline duct. Scale bar: 1 mm.

FIGURE 6. Neopolystoma grossi n. sp. A, marginal hooklets 1 from holotype and paratypes; B, marginal hooklets 2 - 8 from holotype and paratypes. Scale-bars: 10 µm.

FIGURE 7. Paratypes of Neopolystoma grossi n. sp., demonstrating its ability to stretch. Scale bar: 1 mm.