Polystoma floridana, Du, Louis H., Verneau, Olivier & Gross, Timothy S., 2007

Du, Louis H., Verneau, Olivier & Gross, Timothy S., 2007, Polystoma floridana n. sp. (Monogenea: Polystomatidae) a parasite in the green tree frog, Hyla cinerea (Schneider), of North America, Zootaxa 1663, pp. 33-45 : 37-39

Polystoma floridana n. sp.

( Figs. 1–3 )

Specimens studied: Twenty four sexually mature worms and 30 oncomiracidia. Holotype (USNPC 100411) and 6 paratypes (USNPC 100412 - 100417) deposited in the US National Parasite Collection, Beltsville, Maryland, USA; 6 paratypes (NMB P303-308) in the Parasitic Worm Collection, National Museum, Aliwal Street, Bloemfontein, South Africa; remaining specimens in the collection of first author.

Type host: Hyla cinerea Schneider, 1799 sexually mature male ( NMB A 7517) deposited in the Amphibian Collection, National Museum, Bloemfontein 9300, South Africa.

Type locality: Small pond in Deer Run neighbourhood, Gainesville, Florida, USA (29o 42' 12" N 82o 23' 52” W).

Other records: Infected specimens of H. cinerea were found killed on the road at the United States Geological Survey USGS-BRD facility, 7920 N.W. 71st St., Gainesville, Florida, USA (29o 43' 31" N 82o 25' 04” W).

Site: Urinary bladder.

Etymology: The specific name floridana refers to the state Florida.

Description. Based on egg-producing adults (n = 24); measurements given in micrometres. The average measurement is followed by the range in parenthesis. Larval sclerite characters based on oncomiracidia (n = 30) hatched from eggs released by the holotype, paratypes and other specimens.

Adult: General characteristics of mature, egg-producing parasite ( Figure 1 ) typical of Polystoma . Body elongate, total length 6881 (4680–9080), greatest width 2415 (1480–2940), haptor length 917 (640–1300), width 1569 (640–1880); haptor length to body length ratio 0.14 (0.09 – 0.22); haptoral suckers 6, mean diameter 340 (241–420); hamuli 281 (202–350); hamulus hook or blade 40 (33–51). Mouth subterminal, ventral. Oral sucker 239 (155–303) wide; pharynx length 247 (163–311), width 209 (156–319). Intestine bifurcate with small lateral diverticula averaging 22 (10–29) and medial diverticula 9 (4–12). All specimens with 0 – 6 (2.9) or anastomoses; caeca confluent posteriorly, extending into haptor.

Testis follicular, ventral, medial and posterior to ovary ( Figure 1 ). Seminal vesicle packed with sperm. Genital atrium median, ventral, posterior to intestinal bifurcation; genital bulb with (8 – 11) spines 22 (21–24) long. Ovary sinistral, 25 % from anterior end, ovary length 906 (606–1151), width 460 (326–591). Short tubular uterus only anterior to ovary, containing only one egg; egg capsule length 195 (185–210), width 163 (161– 169). No indication of intrauterine development, eggs operculated. Vitellaria throughout most of body. Genito-intestinal canal prominent, on same side as ovary, joining intestinal caecum posterior to ovary ( Figure 1 ).

Oncomiracidium: Ciliated larva with narrow cylindrical body and circular cup-shaped opisthaptor bearing 16 marginal hooklets. Marginal hooklet C1 24.4 (23.3–25.7); hamulus primordial 10.6 (9.0 – 10.6) ( Figure 2 ). Remarks. Polystoma floridana n. sp. differs from other members of the genus by a combination of characters. Polystoma floridana n. sp. with an average length of 6881 and a maximum of 9080 is twice the size of P. nearcticum with an average length of 3600. The smallest specimen recorded in the present study was longer than the largest specimen reported for P. nearcticum . In a plot of the products of the total length (a in Figure 3 ) and the width at the level of the guard (c in Figure 3 ) versus the product of the total length versus the length of a tangent between the tip of the blade to the guard (b in Figure 3 ) of marginal hooklet C1 ( Du Preez and Maritz 2006), P. floridana n. sp. occupies a distinct position separate from P. nearcticum ( Figure 3 ). Polystoma floridana n. sp. is distinguished from other nearctic and neotropical Polystoma species by a combination of characters. With its body length of (4680 – 9080) it is distinguished by size from P. cuvieri (2400 – 4200), P. napoensis (3120 – 3470) and P. touzeti (4180). Polystoma praecox has no anastomoses, while P. floridana n. sp. has up to six. Based on a hamulus length of 202 – 350 P. floridana n. sp. can be distinguished from P. andinum (370 – 480), P. borelli (350 – 530), P. diptychi (890 – 970) and P. lopezromani (544 – 606). The haptor length of (640–1300) for P. floridana n. sp. separates it from P. naevius (1460 – 1890) and the haptor length as percentage of body length of 13% separates P. floridana n. sp. from P. stellai (20%).

Note. H.m. refers to Hemisus marmoratus . P. dawiekoki specimens, i.e. numbers 5 and 6, are from South Africa and Tanzania respectively. All specimens of W. almae , i.e. numbers 8, 9 and 10, are from the same area in French Guiana but 9 was collected in 1994 and 8 and 10 were in 2003. All specimens of P. floridana n.sp, i.e. numbers 15, 16 and 17, are from the same area in USA (Florida), but 15 and 17 were collected in 2003 and 16 in 2004.

1 2 3 4 5 6 7 8 9 16 P.floridana n.sp. 54 56 50 50 53 53 50 49 61 17 P. floridana n.sp. 54 56 50 50 53 53 50 49 61 18 P. floridana n.sp. 54 56 50 50 53 53 50 49 61

continued. Note. H.m. refers to Hemisus marmoratus P. m a r m o r a t i specimens, i.e. numbers 3 and 4, are from South Africa. P. dawiekoki specimens, i.e. numbers 6 and 7, are from South Africa and Tanzania respectively. All specimens of W. almae , i.e. numbers 9, 10 and 11, are from the same area in French Guiana but 10 was collected in 1994 and 9 and 11 were in 2003. All specimens of P. sp (H.c.), i.e. numbers 16, 17 and 18, are from the same area in USA (Florida), but 16 and 18 were collected in 2003 and 17 in 2004.

Figures

FIGURE 1. Polystoma floridana n. sp. Ventral view of holotype; dotted line indicates the outline of the vitelline system. Abbreviations: gb, genital bulb; gi, genito-intestinal canal; ha, hamulus; hp, haptor; ic, intestinal caecum; mg, Mehlis’ gland; mo, mouth; ot, ootype; ov, ovary; ph, pharynx; su, sucker; vg, vagina; vd, vas deferens; vi, vitellaria; vt, vitelline duct. Scale bar: 1 mm.

FIGURE 2: Polystoma floridana n. sp. A, hamuli; B, marginal hooklets 1 from holotype and paratypes; C, marginal hooklets 2 from holotype and paratypes; D, marginal hooklets 8 from holotype and paratypes; E, hamulus primordia. Scale-bars: A, 500 µm; B – E, 20 µm.

FIGURE 3: Scatter diagram of a x b plotted against a x c for P. floridana n. sp. and P. nearcticum. Measurements for oncomiracidia of P. nearcticum were obtained from specimens in the collection of Prof. R. C. Tinsley and the US National Parasite Collection in Beltsville, Maryland, USA.