Systematic Parasitology 7, 69-73. © 1985, Dr W. Junk Publishers, Dordrecht. Printed in the Netherlands.

Deurithitrema gingae n.g., n.sp. (Digenea: Plagiorchioidea) from the kidneys of a salt-water crocodile (Crocodylus porosus Schneider) from Australia

David BLAIR

Department of Zoology, University of Canterbury, Christchurch, New Zealand

Summary

The name Deurithitrema gingae n. g., n. sp. is proposed for worms from the kidneys of one Crocodylus porosus from Darwin, Northern Territory, Australia. The following combination of characters distinguishes the new genus from all others: prepharynx very short; oesophagus absent; caeca reaching to posterior end of body; testes tandem in middle third of body, contiguous or amost so; cirrus-sac large, over-reaches ventral sucker, contains bipartite seminal vesicle, prostatic regions and ejaculatory duct with spines around its opening into genital atrium; genital pore immediately in front of ventral sucker; uterus coiled to posterior end of body; vitellaria lateral from ventral sucker to slightly behind testes; excretory vesicle small, receiving a single ventro-lateral duct from each side behind end of uterine loops. Deurithitrema belongs to the superfamily Plagiorchioidea Dollfus, 1930. It superficially resembles a number of genera, but its relation- ships within the superfamily are obscure.

Introduction

Twenty-one specimens of the new trematode were received from Mrs. Jenny Purdie of the Northern Territory Department of Primary Production. They were from the kidneys of a male crocodile (Crocodylusporosus) caught in Darwin Harbour in April, 1982 and transferred to the crocodile farm at Noonamah. The crocodile was approximately 1.5 m in length and was estimated to be four to five years old. It was in poor physical condition when caught and continued to deteriorate until its death six weeks later. While at the farm it was fed on minced fish, but received no veterinary treatment. On post-mortem examination, conducted by Dr. G. Best on 2nd June 1982, 200 to 300 worms were noticed in the kidney(s) (whether in one kidney or in both not stated in report). The worms were

mostly free in the medulla and lumen of the larger drainage areas of the medulla. There was no obser- vable gross pathology.

The specimens had been fixed initially in alco- hol. Whole mounts were made of 12 specimens stained with Gower's carmine and mounted in Canada balsam. Sagittal sections were cut of an- other three worms, and transverse sections of a further six, although many of the latter were in- complete specimens. Measurements given in the text were taken from whole mounts in ventral view. Because of their condition, not all measurements could be obtained from each worm. Measurements are therefore given as the range, followed by (in parentheses) the mean and the number of observa- tions upon which each was based.

70 Deurithitrema gingae n.g., n.sp. from Crocodylus porosus in Australia

Deurithitrema n.g.

Diagnosis Body elongate, spinose. Fore-body dorso-ventrally compressed, hind-body cylindrical or subcylindri- cal. Oral sucker subterminal ventral; pharynx pres- ent; pre-pharynx very short;oesophagus absent; caeca reaching posterior end of body. Ventral sucker about one third along body, slightly larger than oral sucker. Testes ovoid, tandem, contiguous or almost so in middle third of body. Genital pore median or almost so, immediately in front of ven- tral sucker. Cirrus sac extending well posterior to ventral sucker, containing seminal vesicle which is usually bipartite, prostatic regions and spines around opening of ejaculatory duct into muscular genital atrium. Ovary ovoid, median or submedian right, between ventral sucker and anterior testis. Seminal receptacle between ovary and anterior tes- tis. Laurer's canal present. Uterus coiled, intercae- cal, reaching posterior end of body; metraterm short. Vitellaria in lateral fields from ventral sucker to slightly behind posterior testis. Excretory open- ing terminal; small bladder appears to receive single ventro-lateral duct from each side posterior to uterine coils. Parasites in kidneys of crocodiles.

Etymology The generic name is derived from the Greek words

Deur'ithi, meaning 'come hither'. This is descrip- tive of the beckoning appearance of the large spines in the genital atrium.

Deurithitrema gingae n.sp. (Figs. 1A, B, C, D)

Description Body elongate, 4.51-6.34 (5.47; n = 12) long, 0.31- 0.43 (0.37; n = 10) wide at ventral sucker. Fore- body dorso-ventrally compressed, tapering slightly anteriorly; hind-body cylindrical or subcylindrical, with sides almost parallel but widest slightly ante- rior to truncate, often indented posterior end. Tegument with spines which are smaller and more numerous towards anterior end. Oral sucker termi- nal 0.12-0.19 (0.15; n = 10) long, 0.15-0.18 (0.16; n = 8) wide, with mouth directed antero-ventrally;

prepharynx very short and difficult to detect; phar- ynx 0.069-0.084 (0.079; n = 10) long, 0.077-0.089 (0.083; n=10) wide; oesophagus absent; caeca simple, diverging gradually from midline to pass laterally of other organs and terminating close to posterior end of body. Ventral sucker at end of first quarter or first third of body, 0.21-0.35 (0.3; n = 11) long, 0.25-0.32 (0.29; n = 10) wide. Testes a pair, ovoid, tandem, contiguous or almost so, occupying almost entire width of body in middle third of body length. Anterior testis 0.45-0.56 (0.52; n =11) long, 0.29-0.40 (0.35; n = 11) wide; posterior testis 0.43-0.64 (0.55; n = l l ) long, 0.30-0.42 (0.35; n = 11) wide. Sperm duct arising from antero-ven- tral region of each testis; ducts passing separately to base of cirrus-sac which they enter together. Genital pore small, inconspicuous, median, im- mediately in front of ventral sucker. Cirrus-sac generally submedian, left, large, 0.50-0.76 (0.66; n = 10) long, extending posteriorly behind ventral sucker, its base dorsal to ovary. Cirrus-sac thin- walled, divided into two unequal portions by a slight constriction dorsal to right margin of ventral sucker. Basal portion about 4 times as long as distal and containing a seminal vesicle, usually bipartite, 0.27-0.55 (0.45; n=10) long, 0.12-0.18 (0.15; n = 10) wide within most of its length, then glandu- lar cells surrounding ejaculatory duct distally. Dis- tal portion of cirrus-sac generally globular and con- taining glandular cells only around distal end of ejaculatory duct which opens into a pocket in right side of genital atrium. A large curved spine embed- ded in muscular wall of atrium on each side of opening of ejaculatory duct. Smaller spines, 7-10 in number, protrude from wall of atrium in a semicir- cle ventral and posterior to bases of large hooks. Ovary ovoid, 0.22-0.30 (0.25; n = 10) long, 0.15- 0.21 (0.18; n = 10) wide, in midline or slightly to right of it, approximately midway between anterior testis and ventral sucker. Mehlis' gland posterior to ovary. Oviduct arising dorsally, receiving Laurer's canal from dorsal surface and then yolk duct before entering ootype. Seminal receptacle large, elong- ate, undulating, posterior to Mehlis' gland, oc- cupying most of body length between ovary and anterior testis. Vitellaria follicular, in field lateral or dorso-lateral to caecum on each side; slightly

D. Blair 71

B C ~ GP,

I

CS _ . ~

x til '/ i - ' * ~ ; ,0.05 mm~'----1~ ~ . . . . . ~ . . ~ ~ '~

, O.05mm ,

CS YD LC SR

~ .d..-:C..~. -d..<- ~ ~-'~..s..F.~ ~..~.~.<..<A..< .-". . . . . . . . . . . . . . . . . . . . . . .

: ~::,¢~_-- ...... ; \ .z]-. ~ <.

_

D , 0 . 1 m m , 0 M~

Fig. 1. D e u r i t h i t r e m a g i n g a e n. sp. (A) whole mount in ventral view (composite diagram). (B) Ventral view of terminal genitalia (wholemount in C.I.P. Collection)). (C) Transverse section through genital atrium. (D) Semi-diagrammatic view of female organs and proximal ducts from left side. The following have been omitted from the drawing; gut caeca, vitellaria, sperm ducts leading to base of cirrus sac, excretory ducts.

Key to lettering: AU, ascending arm of uterus; CS, cirrus-sac; GA, genital atrium; GP. genital pore; LC, Laurer's canal; M, metraterm; MG, Mehlis' gland; O, ovary; SR, seminal receptacle; YD, transverse yolk duct.

72 Deurithitrema gingae n.g., n.sp. from Crocodylus porosus in Australia

overlapping or almost reaching level of ventral sucker at anterior end, terminating posterior to level of posterior testis. Fields on opposite sides of body do not always terminate at same level. Trans- verse yolk duct postero-dorsal to ovary where it is sometimes dilated as a small yolk reservoir. Uterus running posteriad dorsal to testes, then tightly coiled between caeca, occupying almost entire body posterior to testes; ascending arm passing anteriad ventral to testes and ovary. Metraterm muscular, short, commencing dorsal or dorso-lat- erai to ventral sucker, surrounded by glandular cells, especially distally, before opening into left side of genital atrium which is partially surrounded by similar glandular cells. Eggs operculate. Eggs dissected from uterus 0.030-0.037 (0.034; n = 10) long, 0.019-0.021 wide. Excretory pore terminal; excretory bladder small, posterior to uterine loops. Courses of excretory ducts not clearly seen in sec- tions, but apparently a single ventro-lateral duct on each side enters bladder posterior to end of uterine loops. Single duct on each side possibly divides into two parallel ducts in region of ventral sucker.

Host

Crocodylus porosus

Site in host Kidney

Geographical information and date Darwin crocodile farm, Noonamah, Northern Ter- ritory, Australia, 2.vi.1982; coll. G. Best.

Specimens deposited In South Australian Museum, Adelaide, South Australia: Holotype (wholemount(V 3541) and six paratypes (3 as wholemounts (V 3542-44), 2 as serial transverse sections (V 3545-46), one as serial saggital sections (V 3547)). In Commonwealth In- stitute of Parasitology Collection: 3 paratypes (2 as wholemounts; one as serial transverse section) (S 1069).

Etymology The specific name is derived from 'ginga/kinga', a

Northern Territory Aboriginal name for the croco- dile.

Discussion

On the basis of adult morphology, Deurithitrema belongs within the superfamily Plagiorchioidea Dollfus, 1930, but its relationships within the group are not clear. Stunkard & Gandal (1966) com- mented that the plagiorchioids 'have undergone extensive modifications from their invasion of di- verse hosts and varied locations, and evaluation of their taxonomic relations is very difficult'. That there are taxonomic difficulties with the group can clearly be seen by a comparison of the classifica- tions proposed by Skrjabin (1958), by Odening (1964) and by Yamaguti (1971) together with com- ments by Gupta & Sharma (1973). On the basis of adult morphology, Deurithitrema appears most closely allied with the group of genera placed by Yamaguti (1971) within the families Macrodero- ididae McMullen, 1937 and Plagiorchiidae (Ltihe, 1901) Ward, 1917. These two families are separated by details of cercarial structure and especially the form of the excretory bladder (generally club- or I-shaped in the former; Y-shaped in the latter). Bladder shapes in adult worms are generally simi- lar to those in their cercariae, but may alter during development. For example, McMullen (1935) dem- onstrated that the cercaria of Macroderoides typ- icus (Winfield, 1929) Van Cleave & Mueller, 1932 has an elongate I-shaped bladder which becomes short and bag-shaped in the adult. This led McMullen (1937) to transfer Macroderoides Pearse, 1924 from the Allocreadiidae to the Macro- deroididae. The bladder in Deurithitrema is very small and difficult to compare with bladders of genera within the Plagiorchiidae and Macrodero- ididae. It is unfortunate that the specimens avail- able were not suitable for more detailed observa- tions on the excretory system. In the absence of appropriate life-cycle information, it is best to re- gard Deurithitrema as a genus incertae sedis within the superfamily Plagiorchioidea but probably be- longing to the Macroderoididae or the Plagi- orchiidae.

The new genus does not seem very close to any of those genera included in the Macroderoididae or Plagiorchiidae by Yamaguti (1971) and may be dis- tinguished from all of them by the following com- bination of characters: prepharynx very short; oesophagus absent; caeca reaching posterior end of body; testes tandem in middle third of body, con- tiguous or almost so; cirrus-sac large, containing bipartite seminal vesicle, prostatic regions and ejaculatory duct; genital pore immediately in front of ventral sucker; uterus coiled to posterior end of body; vitellaria lateral, extending from ventral sucker to slightly behind posterior testis; excretory bladder small, receiving tributary ducts posterior to uterine coils.

In addition, Deurithitrema is unique in the ar- rangement of spines in the terminal genitalia. Some genera in the group under discussion have spines associated with their terminal genitalia (Plagi- orchis L/ihe, 1899 (e.g., P. noblei Park, 1936); Enodiotrema Looss, 1900; Oistosomum Odhner, 1902; Travtrema Pereira, 1929; Spinometra Mehra, 1931; Glossimetra Mehra, 1931 (syn. of Allopharynx (Shtrom, 1928) according to Acholonu, 1976); Paralepoderma Dollfus, 1950 (e.g., P. osmanii Rao, 1980)) but in none of these genera does the spination resemble that in Deurithitrema.

Few plagiorchioids of the families Macrodero- ididae or Plagiorchiidae are known from the urino- genital system of reptiles. Those that are, members of the genera Lechriorchis Stafford, 1905, Mano- distomurn Stafford, 1905, Paurophyllum Byrd, Par- ker & Reiber, 1940 and Styphlodora Looss, 1899, are not close to Deurithitrema in their morphology.

Acknowledgements

The author wishes to thank all those whose interest in crocodiles and their parasites led to the prep-

D. Blair 73

aration of this paper. Dr. D.M. Spratt, CSIRO Division of Wildlife Research, Canberra, provided the initial liaison with workers in Darwin. Mrs. Jenny Purdie forwarded the specimens and rele- vant information. Dr. G. Best performed the post- mortem examination of the crocodile and found the worms. Thanks are also due to Dr. G. Zanker, University of Canterbury, for assistance with the Greek name chosen for the genus.

References

Acholonu, A.A. (1976) Helminth fauna of saurians from Puerto Rico with observations on the life-cycle of Lueheia inscripta (Westrumb, 1821) and description of Allopharynx puerto- ricensis sp.n. Proceedings of the Helminthological Society of Washington, 43, 106-116.

Gupta, A.N. & Sharma, P.N. (1973) Status of the genus Glossi- metra Mehra, 1937 (Family Plagiorchidae (Lfihe, 1901) Ward, 1917) in Styphlotrematinae Baer, 1924, Astiotrematinae Baer, 1924 and Styphlodorinae Dollfus, 1937 complex. Re- search Bulletin of the Meguro Parasitological Museum, 7, 8-11.

McMullen, D.B. (1935) The life histories and classification of two allocreadiid-like plagiorchids from fish, Macroderoides typicus (Winfield) and Alloglossidium corti (Lamont). Jour- nal of Parasitology, 21, 369-380.

McMullen, D.B. (1937) A discussion of the taxonomy of the family Plagiorchiidae Ltihe, 1901, and related trematodes. Journal of Parasitology, 23, 244--258.

Odening, K. (1964) Zur Taxonomie der Trematodenunter- ordnung Plagiorchata. Monatsbericht der Deutschen Akademie der Wissenschaftlichen zu Berlin, 6, 191-198.

Skrjabin, K.I. (1958) [Trematodes of animals and man.] Moscow: Akademiya Nauk, Vol. 14,934 pp. [in Russian].

Stunkard, H.W. & Gandal, C.P. (1966) A digenetic trematode, Parahaplometroides basiliscae Thatcher, 1963, from the mouth of the crested lizard, Basiliscus basiliscus. Zoologica, 51, 91-95.

Yamaguti, S. (1971) Synopsis of digenetic trematodes of verte- brates. Tokyo, Japan: Keigaku Publishing Co., 1074 pp.

Accepted for publication 12th December, 1983.