Overview of South African Dendromonocotyle (Monogenea: Monocotylidae), with descriptions of 2 new species from stingrays (Dasyatidae) kept in public aquaria Author Vaughan, David Author Chisholm, Leslie Author Christison, Kevin text Zootaxa 2008 1826 26 44 journal article 10.5281/zenodo.183100 5553f72c-9d53-4d71-a444-ea5c80c0c7de 1175-5326 183100 Dendromonocotyle ukuthena n. sp. ( Figs. 2 A, 4C–4E, 4G, 5–7) Type host: Himantura gerrardi (Gray) . Additional host: Himantura uarnak (Forsskål) . Type locality: uShaka Sea World, Durban, South Africa . Site on host: Dorsal skin surface. Etymology: This species is named after the Zulu word “ ukuthena ” which is the ritual of becoming-of-age, in recognition of the opening of uShaka Marine World in KwaZulu Natal . Materials examined: SAMCTA 29455 ( holotype ), SAMCTA 29456 (18 paratypes ), SAMCTA 29457 ( paratype with spermatophore), SAMCTA 29458 ( paratype with missing distal portion of male copulatory organ), AHC 29290 (5 paratypes ), BMNH 2008.6.25.1-5 (5 paratypes ). Description. Based on 17 flattened adult specimens. Total body length 1946 ± 750.5 (1250–3290, n = 6). Body-proper length 1957 ± 634.3 (1000–3580, n = 17), and 1522 ± 395.2 (790–2110, n = 17) maximum width ( Fig. 5 A). Circular haptor, 1540 ± 455.8 (810–2110, n = 14) in diameter ( Fig. 5 B), large in proportion to body, with edge of marginal valve extending beyond anterior section of ovary. Haptor with 8 peripheral and 1 central loculus and 56 marginal haptoral papillae, each with between 5 and 6 sclerites including the terminal papillary sclerite ( Figs 5 F, 5G). Outer ring, inner ring and septal sclerites as illustrated ( Figs 5 C–E). Tripartite sclerites at junction of radial septa and inner-ring septum in most specimens. Anterior loculus pair associated each with 6 marginal haptoral papillae, anterolateral and posterolateral loculi each associated with 7 marginal haptoral papillae, and posterior-most loculus pair each associated with 8 marginal haptoral papillae. Hamuli present ( Figs 5 B, 5H), 73 ± 3.7 (68–80, n = 11) long. Fourteen marginal hooklets ( Fig. 5 I), 15 ± 0.5 (14–15, n = 10) long distributed in marginal value between every 4 marginal haptoral papillae ( Figs 2 A, 5B). Mouth anterior to pharynx. Subterminal groove anterior to mouth. Six anterior gland duct openings open laterally on anterior end of worm as illustrated ( Fig. 5 A). Eye spots likely present but only observed in juvenile specimens, obscured by heavily pigmented branches of intestinal caecum. Pharynx 247 ± 75 (110–360, n = 12) long, and 200 ± 53.4 (120–300, n = 13) wide. Dendritic intestinal caecum dense, heavily pigmented. Branches extend from anterior end of body-proper, dorsal and anterior to pharynx, and extend to end of body-proper. Testis 181 ± 28.2 (150–240, n = 11) long, and 365 ± 59.7 (290–450, n = 11). Vas deferens runs dorsal to vagina, ventral to male copulatory organ before swelling to form seminal vesicle. Ejaculatory bulb situated left to centre of body-proper, 171 ± 28.8 (140–220, n = 10) long, and 161 ± 26.4 (110–200, n = 10) wide. Male copulatory organ 486 ± 32 (440–530, n = 10) long, and 11 ± 1.1 (10–14, n = 15) wide; surrounded by muscular sheath, 76 ± 2.5 (75–80, n = 4) wide ( Figs 4 C, 5A). Distal portion of male copulatory organ sclerotised with criss-crossed sperm duct ( Fig. 4 D). Distal portion of male copulatory organ absent in 5 specimens ( Figs 4 C, 4E). Possible breakage point and area of regrowth on distal portion of male copulatory organ seen in a number of specimens ( Fig. 4 G). Ovary ovoid, 154 ± 25.7 (110–190, n = 12) long, 543 ± 57.2 (460–640, n = 12) wide. Ootype 223 ± 15 (210–240, n = 4) long with tetrahedral egg side length 88 ± 5 (80–90, n = 4). Short filament 43 ± 5.8 (40–50, n = 3) extends from 1 pole, ending in blunt, rounded butt ( Fig. 7 A). Muscular vagina distinct 648 ± 23.8 (610–670, n = 5) long. Vaginal pore on left side of body at level of posterior portion of pharynx; leading to vaginal chamber with inner-ring of sclerotised spines embedded in thick musculature ( Figs 5 A, 6A, 6B). Vagina narrows then swells slightly to enter ovoid seminal receptacle 110 ± 12.2 (100–130, n = 5) long, and 145 ± 39.3 (100–190, n = 5) wide. Duct from seminal receptacle to oviduct not seen. Transverse vitelline duct inconspicuous, running just anterior to ovarian loop, crossing over proximal portion of vagina. A spermatophore 230 (n = 1) long, and 60 (n = 1) wide, with distal portion resembling the distal tip of the male copulatory organ present in 1 specimen (SAMCTA 29457) ( Fig. 6 C). FIGURE 5. Dendromonocotyle ukuthena n. sp. A. Ventral view of body-proper, composite; note vaginal sclerites (vs). B. Haptor with hamulus (ham). C. Outer ring sclerites. D. Inner ring sclerite. E. Septal sclerites. F. Papillary sclerites. G. Terminal papillary sclerite. H. Hamulus. I. Marginal hooklet. Scale bars: A = 500μm; B = 300μm; C–I = 10μm. FIGURE 6. Dendromonocotyle ukuthena n. sp. A. Vagina showing inner-ring of vaginal sclerites (vs). B. Single vaginal sclerite (vs) with muscle attachment (m). C. Spermatophore within the vagina (iv). Note the criss-crossed sperm duct (sd) at the distal end of the spermatophore. Scale bars: A = 500μm; B = 200μm; C = 100μm. FIGURE 7. Dendromonocotyle ukuthena n. sp. egg and oncomiracidium. A. Single egg with club-shaped filament. B. Egg with forming oncomiracidium; note eyespot (es) development. C. Egg with fully embryonated oncomiracidium. D. Hatching oncomiracidium. E. Oncomiracidium: F. Refringent droplets in ciliated epithelial cells. Abbreviations: ab, anterior band of ciliated cells; cl, crystalline lens; hb, haptoral band of ciliated cells; mp, median patch of ciliated cells; p, pharynx; pb, pigmented band. Scale bars = 30μm. TABLE 1. Comparative measurements of Dendromonocotyle citrosa n. sp. from Dasyatis chrysonota kept at Two Oceans Aquarium, Cape Town and D. citrosa from Himantura gerrardi kept at uShaka Sea World, Durban. Measurements (µm) are expressed as the mean ± the standard deviation followed, in parenthesis, by the range and the number of structures measured.

Structure Measured	D. citrosa ex . Dasyatis chrysonota	D. citrosa ex . Himantura gerrardi
Total body length	2998 ± 563.4 (2390–3600, n = 6)	1373 ± 281.2 (1090–1710, n = 4)
Body length	2280 ± 290.7 (2000–2550, n = 4)	1162 ± 208.0 (900–1460, n = 5)
Body width	1568 ± 102.3 (1500–1750, n = 6)	888 ± 261.3 (500–1150, n = 5)
Hooklets	9 ± 1.1 (8–10, n = 5)	11 ± 0.6 (11–12, n = 3)
Hamuli	absent	absent
Haptor diameter	2195 ± 89.6 (1330–2800, n = 6),	914 ± 233.2 (560–1120, n = 5)
Number of marginal papillae	56	56
Pharynx length	286 ± 19.6 (189–368, n = 6)	133 ± 35.6 (90–185, n = 5)
Pharynx width	179 ± 33.6 (129–229, n = 6)	130 ± 36.6 (80–175, n = 5)
Male copulatory organ length	327 ± 7.3 (315–337, n = 6)	329 ± 19.5 (310–360, n = 5)
Male copulatory organ width	9 ± 0.6 (8–9, n = 4)	7 ± 1.1 (6–8, n = 5)
Male copulatory organ sheath width	58 ± 5.0 (50–60, n = 4)	56 ± 5.9 (50–62, n = 5)
Ejaculatory bulb diameter	190 ± 21.6 (170–220, n = 4)	137 ± 12.0 (125–150, n = 5)
Testis length	243 ± 22.2 (210–260, n = 4)	110 (n = 1)
Testis width	364 ± 32.0 (312–390, n = 5)	225 (n = 1)
Seminal receptacle length	153 ± 27.3 (129–229, n = 6)	45 ± 14.1 (35–55, n = 2)
Seminal receptacle width	103 ± 18.3 (80–131, n = 5)	98 ± 31.8 (75–120, n = 2)
Ootype length	342 ± 69.2 (262–387, n = 3)	186 ± 31.1 (145–220, n = 5)
Ovary length	220 ± 101.5 (110–310, n = 3)	198 ± 31.8 (175–220, n = 2)
Ovary width	540 ± 50.3 (470–590, n = 4)	396 ± 48.8 (350–450, n = 4)
Vagina length	378 ± 28.8 (360–410, n = 3)	350 ± 21.1 (335–365, n = 2)
Egg side length	95 ± 18.0 (80–115, n = 3).	75 ± 4.1 (70–80, n = 4)
Egg filament length	120 ± 14.1 (110–130, n = 2)	84 ± 33.5 (50–130, n = 4)

Egg hatching. Eggs of D. ukuthena are laid singly. Eggs incubated in a LD 12:12 light regime at 23°C contained larvae with eyes ( Fig. 7 B) after 5 days. Eggs incubated at 26°C and 30°C contained larvae with eyes after 3 days. Spontaneous hatching ( Fig. 7 D) commenced at 14, 5 and 4 days after laying at 23, 26 and 30°C, respectively. FIGURE 8. Dendromonocotyle colorni . A. Ventral view body-proper, composite. B. Haptor including hamulus (ham). C. Outer ring septal sclerite. D. Septal sclerites. E. Inner-ring tripartite sclerite. F. Outer-ring tripartite sclerite. G. Papillary sclerites. H. Terminal papillary sclerites. I. Hamulus. J. Marginal hooklet. Scale bars: A, B = 500μm; C–J = 10μm. Description of oncomiracidium. Observations based on 2 freshly hatched, living oncomiracidia. Larva 168 ± 4.2 (165–171, n = 2) long and 89 ± 1.4 (88–90, n = 2) wide. Ciliated cells in 3 zones; 1 anterior band, 2 median patches (1 on each side of body) and 1 haptoral band ( Fig. 7 E). Refringent droplets in ciliated epidermal cells ( Fig. 7 F). FIGURE 9. Dendromonocotyle colorni . A. Hamulus. B. Haptoral papilla showing papillary sclerites (ps) and terminal papillary sclerite (tps). C. Tripartite sclerite (otp) at junction of radial septum and outer-ring septum; papillary sclerites (ps) can also be seen. D. Terminal papillary sclerite (tps). E. Anterior end showing distinct anterolateral gland duct openings (alg). Scale bars: A = 10μm; B = 100μm; C = 50μm; D = 20μm; E = 200μm. Two pairs of pigmented eyes with crystalline lenses arranged as shown ( Fig. 7 E); pairs very close together. Light brown pigment in body distributed in 2 short distinct longitudinal bands on either side of body from level just posterior pharynx ( Fig. 7 E). Mouth not observed. Pharynx muscular, 20 ± 3.1 (17–24, n = 2) in diameter. Glands associated with pharynx not observed. Gut immediately posterior to pharynx, bilobed. Two anteromedian gland cells containing granular secretion just anterior to pharynx; single duct from each gland cell runs anteriorly opening at anterior end. Glands containing needle-like secretion present on either side of pharynx. Protonephridial system not investigated. FIGURE 10. Dendromonocotyle colorni . A. Male reproductive system. B. Distal portion of male copulatory organ showing sclerotised accessory flange (af). C. Female reproductive system; note translucent coiled duct (tcd) of vagina. Scale bars = 100μm. Haptor with 14 hooklets, each of similar shape and size, 12 ± 0.4 (12–13, n = 5) long with domus. Hamuli not observed. Remarks. Dendromonocotyle ukuthena can be distinguished from all other species of Dendromonocotyle by the morphology of the vagina, which possesses a ring of spines embedded within the thick musculature near the vaginal pore ( Figs 5 A, 6A, 6B). Dendromonocotyle taeniurae is the only other species with spines associated with the vaginal pore but the 2 species are clearly differentiated by the morphology of the distal portion of the male copulatory organ. In addition, D. taeniurae lacks hamuli. A spermatophore was present in the vagina of 1 specimen . The distal end of the spermatophore resembles the distal end of the male copulatory organ (c.f. Figs 6 C and 4D) complete with the criss-crossed sperm duct. We also observed that the distal part of the male copulatory organ was missing in 5 of the 17 specimens examined. It is possible that the distal end of the male copulatory organ breaks off during mating to form the spermatophore (see Discussion). Dendromonocotyle ukuthena was found on the same ray specimens as D. citrosa at uShaka. Sea World, Durban. Eyespots were observed in the larvae and juvenile D. ukuthena but were obscured by the darkly pigmented intestinal caeca in adult specimens.